Allied Health & Imaging · Independent exam preparation
ARRT Computed Tomography Examination: Free Preparation Guide Study Guide
Practise contrast safety, dose calculations, reconstruction choices and regional CT protocols with 60 focused concepts, 20 explained questions and recall cards.
By CertMedbry · Updated 14 October 2026
Learn to distinguish contrast emergencies, interpret CT dose indices, select useful reconstructions and match regional protocols to the clinical question. This guide targets entry-level CT knowledge for ARRT certification and registration through the postprimary pathway, using the specifications effective September 1, 2026. Its 60 concepts are selective: the official ARRT examination content outline defines the full scope. Use the cases to explain decisions, then test those explanations with independent questions and flashcards.
Try 20 free practice questionsWhat is the exam format?
Check the question types, timing and outline before planning your revision.
Which examination and credential pathway does this guide cover?
This guide covers ARRT's Computed Tomography Examination for certification and registration in CT through the postprimary eligibility pathway. The examination assesses knowledge underlying entry-level CT practice. CT requires an approved supporting credential together with applicable education, clinical experience, ethics and examination requirements. Different supporting credentials lead to this CT pathway; they do not create separate CT examination variants.
ARRT Computed Tomography (CT) · ARRT Computed Tomography Examination Content Specifications
Which blueprint applies, and what changed?
The applicable specifications were board approved in July 2025, carry version V2025.09.15, and took effect September 1, 2026. The issuer's change notice highlights time-out, injection and scanning techniques, adverse-event reporting, informatics, expanded cardiac content, and additional gastrointestinal and urinary studies. Earlier specifications are historical for this guide. Examination specifications, structured-education requirements and structured self-assessment specifications are separate documents.
ARRT Computed Tomography Examination Content Specifications · ARRT Updated CT Documents · ARRT Reference Documents by Discipline
How many scored and pilot questions are included?
The examination contains 165 scored questions and 30 additional unscored pilot questions, totaling 195. ARRT states that pilot questions appear randomly and cannot be distinguished from scored questions. Treat every question as worthy of your best answer.
ARRT Computed Tomography Examination Content Specifications · Exam Duration and Length - ARRT
How are the scored questions distributed?
Patient Care has 21 scored questions, Safety 21, Image Production 52 and Procedures 71. These correspond to approximately 12.73%, 12.73%, 31.52% and 43.03%. Image Production divides into Image Formation 30 and Image Evaluation and Archiving 22. Procedures divides into Head, Spine, and Musculoskeletal 25; Neck and Chest 22; and Abdomen and Pelvis 24. This guide uses 8, 8, 19 and 25 concepts; its questions and cards each use 3, 2, 6 and 9 items.
What duration should candidates plan for?
The 2026 ARRT postprimary handbook lists 195 minutes of CT test time and a 215-minute appointment. The additional 20 minutes comprise eight minutes for the tutorial, two minutes for the nondisclosure agreement and ten minutes for the post-examination survey. Distinguish the time available for answering examination questions from the complete appointment duration.
What delivery and question formats are described?
ARRT exams are computer-based and begin with a tutorial containing practice questions. The 2026 handbook explains that most questions require one best answer. Other possible formats include selecting multiple answers, ordering responses, selecting an image and answering questions following video clips. These possibilities do not establish that every CT examination contains every format or that delivery is adaptive. This guide's 20 questions are independent four-option, single-best-answer drills; they do not reproduce the complete examination interface or its range of possible item styles.
Does the September 2026 passing-standard update establish a raw passing percentage?
No. ARRT's August 27, 2026 notice states that the updated CT passing standard applies to candidates testing on or after September 1, 2026. That implementation date does not establish a raw percentage of correct answers. This guide makes no raw passing-percentage claim and its practice scores do not predict passing.
ARRT Updates Passing Standard for the Computed Tomography Examination
How does ARRT certification differ from state licensing?
ARRT certification and registration and state licensing have different requirements. A state examination score does not by itself confer ARRT certification, and an ARRT credential does not automatically authorize practice in every state. This guide selects the ARRT postprimary CT certification and registration pathway; candidates seeking state authorization must separately determine the applicable jurisdiction's requirements.
ARRT's Computed Tomography Examination assesses CT technologist knowledge and cognitive skills. This independent educational guide approximates its domain weighting and connects acquisition physics with patient care and procedure selection. It is not an official ARRT question bank or a prediction of examination performance.
Outline used: ARRT Computed Tomography Examination Content Specifications, board approved July 2025, effective September 1, 2026; document V2025.09.15. The assigned workbook label maps to this examination for ARRT certification and registration in CT; the assigned slug is preserved.
60 key concepts: understand, apply and avoid the traps
Work through the questions by exam domain. Explain the answer in your own words, try the example, then check the common pitfall.
Patient Care21/165 scored questions (approximately 12.73%)
1.Which contrast history most strongly changes reaction-risk assessment?
A previous allergic-like reaction to the same class of contrast is a major predictor of another reaction. Ask what agent was administered, which symptoms occurred, their severity and how they were treated. Warmth or brief nausea represents a different mechanism from urticaria, bronchospasm or airway swelling. Shellfish allergy does not uniquely predict iodinated contrast reactions. The discriminating cue is the patient's actual contrast-reaction history, rather than an imprecise label such as iodine allergy.
Apply it
Two patients report allergies: one had wheezing after iodinated contrast, while the other develops hives after eating shrimp. Identify the previous contrast-associated wheezing as the history requiring specific reaction-risk planning before injection.
Common pitfall: Treating every reported allergy as equivalent obscures the most relevant history. A vague allergy label should be clarified rather than converted automatically into a contrast contraindication.
2.How do renal function and metformin affect contrast preparation?
Renal assessment distinguishes stable chronic impairment from acute kidney injury; creatinine alone can conceal differences in filtration. Metformin does not itself increase contrast-associated kidney injury, but accumulation during significant renal dysfunction raises concern for lactic acidosis. Under ACR guidance, patients without acute kidney injury and with eGFR at least 30 mL/min/1.73 m² generally need not stop metformin for intravenous iodinated contrast or undergo obligatory postprocedure renal reassessment solely because of metformin. In patients with acute kidney injury or eGFR below 30, discontinue metformin at or before the procedure, withhold it for 48 hours afterward and reassess renal function before restarting. ACR also places arterial catheter studies that could embolize the renal arteries in this precaution category. These medication precautions do not constitute an absolute prohibition on necessary contrast imaging.
Apply it
A patient taking metformin has stable eGFR 58 and no acute kidney injury before an intravenous contrast examination. Explain why metformin alone does not require interruption under ACR guidance. For a second patient with acute kidney injury, identify withholding through the next 48 hours and renal reassessment before restart as essential parts of medication planning.
Common pitfall: Automatically withholding metformin from every contrast recipient confuses medication accumulation risk with contrast nephrotoxicity. Conversely, completing 48 hours does not by itself establish that restarting is appropriate. ACR guidance and FDA labeling may differ in their precaution criteria.
3.How do allergic-like and physiologic reactions differ, and which treatments match their mechanisms?
Allergic-like reactions include urticaria, angioedema and bronchospasm; physiologic reactions include warmth, nausea and vasovagal episodes. Hypotension with bradycardia suggests a vasovagal pattern; hypotension with tachycardia and airway symptoms suggests anaphylaxis. Stop contrast administration, assess airway and circulation, preserve IV access, provide oxygen and activate emergency assistance for severe features. Isotonic IV fluid supports circulation during hypotension. Epinephrine is central treatment for anaphylaxis and laryngeal edema; it supports vascular tone and bronchodilation. Atropine treats refractory vasovagal bradycardia by opposing vagal effects. An inhaled beta-2 agonist such as albuterol treats bronchospasm; severe or unresponsive bronchospasm may require epinephrine. Antihistamines can address skin symptoms but do not replace epinephrine for anaphylaxis. Appropriately authorized personnel administer medications using current treatment guidance, with route, concentration and monitoring matched to the situation.
Apply it
Diffuse hives, wheezing and hypotension with tachycardia after injection indicate anaphylaxis: activate emergency assistance and anticipate epinephrine, oxygen and fluid support. Contrast this with persistent hypotension and bradycardia despite supportive measures, where atropine addresses the vasovagal mechanism. As an adult dose calculation from the ACR reaction card, 0.3 mL of 1 mg/mL epinephrine contains 0.3 mg for the specified IM regimen; this concentration must not be confused with an IV preparation.
Common pitfall: Calling all post-injection symptoms allergy can misdirect treatment. Atropine does not treat anaphylaxis, and antihistamines or an inhaler alone do not adequately treat systemic shock. Epinephrine concentration and route errors can cause serious harm.
ACR Manual on Contrast Media · Contrast-Reaction-Card-Adult.pdf
4.When does contrast extravasation require urgent escalation?
Extravasation places injected contrast outside the vessel, where swelling and tissue pressure can cause injury. Stop injection and obtain clinical assessment of pain, swelling, sensation, movement and perfusion. Severe or progressive pain, impaired capillary refill, sensory change, reduced active or passive movement, blistering or ulceration warrant urgent surgical evaluation. Escalation is driven by clinical findings rather than a fixed extravasated-volume threshold. Patients discharged after assessment need clear instructions about worsening symptoms.
Apply it
An injection infiltrates the hand. Although the estimated volume is modest, the patient develops increasing pain, numbness and reduced finger movement. Escalate urgently because neurovascular and movement abnormalities matter more than the volume estimate.
Common pitfall: A small volume does not exclude serious injury in a confined location. Waiting for a large-volume threshold can miss evolving tissue compromise.
5.Which vascular access can safely support power injection?
Power injection requires an access device and connected components that are suitable for the intended pressure and flow. Central location alone does not establish suitability. For a PICC or central venous catheter, verify the specific device's power-injection designation, authorized lumen, pressure and flow limits, patency and appropriate positioning. Peripheral access also requires assessment of the site and catheter. A saline check can assess function, but successful flushing does not establish a device's pressure rating.
Apply it
A patient has a PICC that flushes easily, but its model and power-injection rating are unknown. Do not infer suitability from patency; identify the device and its limits before choosing it for a CTA injection.
Common pitfall: A central catheter is not automatically power injectable. Increasing injector pressure to overcome resistance can endanger the access device and the patient.
6.Why is hand hygiene required even when gloves are used?
Gloves reduce direct contact with contaminants but do not replace hand hygiene. Hands can become contaminated during glove removal, and glove defects can permit exposure. Perform hand hygiene before appropriate patient contact or aseptic tasks and after glove removal. Alcohol-based hand sanitizer is preferred for most routine clinical situations when hands are not visibly soiled. Soap and water are necessary when hands are visibly dirty and in additional circumstances specified by infection-control guidance.
Apply it
After removing gloves used during venipuncture, a technologist immediately reaches for clean injector supplies. Pause for hand hygiene before handling those supplies, even though the hands appear clean and gloves were worn during patient contact.
Common pitfall: Changing gloves without cleaning hands can transfer contamination to the next pair. Visible cleanliness does not establish microbiologic cleanliness after glove removal.
7.How do contrast route and composition determine what becomes visible?
Contrast must reach the compartment being examined. Intravenous iodinated contrast enhances vessels and tissues according to circulation and scan timing; oral or rectal agents outline gastrointestinal contents; intrathecal agents enter the subarachnoid space. Positive agents increase attenuation, whereas water and gas provide different luminal backgrounds. Route-specific formulation matters, especially for intrathecal administration. Iodinated contrast exposure during breastfeeding generally does not require interruption because infant systemic exposure through milk is extremely small.
Apply it
A patient scheduled for CT myelography asks whether the usual intravenous contrast injection is sufficient. Explain that myelography introduces an approved contrast formulation into the subarachnoid space to outline structures around the spinal cord and nerve roots. In a separate hypothetical IV calculation, 100 mL at 350 mg iodine/mL contains 35 g iodine; at 4 mL/s, iodine delivery is 1.4 g/s and injection duration is 25 seconds. These calculations describe the stated injection, rather than prescribe a universal dose.
Common pitfall: An agent's iodine content does not make every formulation interchangeable across routes. Intravenous labeling cannot be assumed to authorize intrathecal use. Distinguish contrast volume, iodine concentration and total iodine mass when calculating an injection.
ACR Manual on Contrast Media · ACR/RSNA RadiologyInfo: Myelography
8.What makes monitoring and emergency readiness effective during contrast studies?
Effective monitoring connects observed changes with personnel able to assess and treat them. New dyspnea, altered consciousness, hypotension or worsening swelling requires prompt evaluation. For virtual physician supervision, ACR recommends at least one qualified licensed practitioner on site in addition to the radiology technologist. That practitioner must have relevant training in patient assessment, physical examination and medication administration; maintain competency in differentiating reactions; recognize intervention needs; administer appropriate prescription medications, including IV medications, within authorized practice; and activate emergency assistance. The supervising physician must communicate directly and bidirectionally with the responsible on-site individual, without another off-site supervisory layer. These are ACR professional recommendations subject to applicable law and facility policy, rather than universal regulatory authorization. A time-out confirms the intended patient and procedure, and monitoring extends through the relevant post-administration period.
Apply it
During a contrast study under virtual physician supervision, a patient develops respiratory distress. Activate the emergency response and engage the additional qualified on-site licensed practitioner immediately while maintaining direct physician communication. Before administration, confirm that the staffing arrangement includes both reaction assessment and medication competencies.
Common pitfall: A video connection cannot provide hands-on treatment. Having only the radiology technologist on site does not satisfy the additional-practitioner condition in ACR's virtual-supervision recommendation. Professional guidance does not supersede jurisdictional restrictions.
Statement from Drugs and Contrast Media Committee on Supervision of Contrast Material Administration · ARRT Computed Tomography Examination Content Specifications
Safety21/165 scored questions (approximately 12.73%)
9.How should pediatric CT balance diagnostic benefit and radiation exposure?
Justification asks whether CT is needed for the clinical question; optimization asks how to obtain adequate diagnostic information with appropriate exposure. Children are more radiosensitive and have more remaining years in which radiation-associated effects could appear. Adjust technique to patient size, restrict coverage to necessary anatomy and avoid additional phases that do not answer a distinct question. The goal is adequate diagnostic quality, not the lowest possible dose regardless of whether the study remains useful.
Apply it
A child needs CT for a defined abdominal question. Review whether an adult multiphase protocol adds useful information; select a size-adjusted examination with justified coverage and phases rather than retaining every adult acquisition by default.
Common pitfall: Using adult settings because the scanner permits them can deliver unnecessary exposure. Reducing technique until images become nondiagnostic also defeats optimization and may lead to repetition.
NCI Radiation Risks and Pediatric Computed Tomography · NCI Computed Tomography Scans and Cancer
10.What does CTDIvol measure, and what does it omit?
CTDIvol is a standardized scanner-output index expressed in milligray, based on measurements using a reference phantom and accounting for acquisition spacing or pitch. It is useful for comparing output under specified conditions, but it is not an individual patient's absorbed dose. Interpretation requires knowing whether the reference phantom is 16 or 32 cm in diameter. Patient size and anatomy affect actual dose, so identical displayed CTDIvol values do not establish identical patient exposures.
Apply it
Two body studies display CTDIvol 8 mGy, but one uses a 16-cm reference phantom and the other a 32-cm phantom. Confirm the phantom basis before comparing output or drawing conclusions about the patients' doses.
Common pitfall: Calling CTDIvol the patient's dose ignores reference-phantom and size differences. The same numerical index can represent different output conditions when phantom bases differ.
AAPM Reports - Size-Specific Dose Estimates (SSDE) in Pediatric and Adult Body CT Examinations · RPT_96.pdf
11.How does scan length affect dose-length product?
Dose-length product, or DLP, equals CTDIvol multiplied by scan length and is expressed in mGy·cm. For constant CTDIvol, extending coverage increases DLP proportionally even when the output index remains unchanged. Examination DLP combines contributions from separate acquisitions, so extra phases can increase total exposure substantially. DLP describes output integrated over length in a reference condition; it does not directly establish organ dose or an individual's radiation risk.
Apply it
A constant-output acquisition has CTDIvol 9 mGy and length 32 cm. Calculate DLP as 288 mGy·cm. Extending the same acquisition to 40 cm raises DLP to 360 mGy·cm without changing CTDIvol.
Common pitfall: An unchanged CTDIvol does not mean unchanged total exposure. Adding anatomy or phases increases DLP even when every acquisition uses the same technique.
RPT_96.pdf · AAPM Reports - Size-Specific Dose Estimates (SSDE) in Pediatric and Adult Body CT Examinations
12.Why does SSDE use patient size and water-equivalent diameter?
Size-specific dose estimate adjusts CTDIvol using a size-related conversion factor matched to the reference phantom. Water-equivalent diameter incorporates attenuation as well as geometric dimensions, making it more informative than external width alone. A thorax and abdomen with equal dimensions do not attenuate identically because the lungs contain air. Image-based calculations should include the patient's cross section while excluding unrelated structures such as the table. SSDE remains an estimate rather than a complete map of individual organ doses.
Apply it
A chest and abdominal cross section have similar external dimensions. Explain why an attenuation-based size measure can distinguish them, and calculate SSDE 12 mGy when the supplied matching factor is 1.5 and CTDIvol is 8 mGy.
Common pitfall: Geometric diameter alone can overestimate attenuation-based size in the thorax. A conversion factor must also match the phantom underlying the displayed CTDIvol.
RPT_220.pdf · AAPM Reports - Size-Specific Dose Estimates (SSDE) in Pediatric and Adult Body CT Examinations
13.When does changing pitch change radiation output?
At fixed kVp, scanner configuration and actual mAs per rotation, CTDIvol varies approximately inversely with pitch because higher pitch spreads irradiation over more table travel. This relationship changes when software increases tube current to maintain effective mAs or a noise target. Effective mAs is actual mAs divided by pitch. Therefore, a pitch change alone cannot guarantee dose reduction: inspect whether actual mAs and the displayed output index also changed.
Apply it
A protocol changes pitch from 1.0 to 1.5 while keeping actual mAs fixed. Predict lower CTDIvol under the stated assumptions. If the scanner raises actual mAs by the same factor, recognize that the expected reduction may disappear.
Common pitfall: Assuming higher pitch always lowers dose ignores automatic compensation. Distinguish actual mAs per rotation from effective mAs before applying an inverse-pitch calculation.
14.Why does centering matter for automatic exposure control?
Automatic exposure control uses attenuation information to adjust tube current for the intended image-quality target. Patient position affects localizer magnification and the relationship between anatomy and the beam-shaping filter. Off-centering can therefore distort size assessment and alter exposure or image quality. Centering is a physical setup decision, not merely a cosmetic adjustment. Confirm position before the localizer used for planning, and reassess positioning if the patient moves before acquisition.
Apply it
A small adult is positioned substantially above the gantry center before the planning localizer. Correct the table position before acquiring the relevant localizer so the exposure-control system receives geometry consistent with the planned examination.
Common pitfall: Assuming exposure control corrects every setup error overlooks its dependence on input geometry. A technically successful localizer can still provide misleading size information.
15.How do filtration, photon energy and tissue interactions influence CT exposure?
An x-ray beam contains a spectrum of photon energies. Filtration preferentially removes lower-energy photons that are more likely to be absorbed without reaching the detectors. Beam-shaping filters distribute output across the patient's cross section. Tube voltage changes the spectrum rather than simply scaling photon number, affecting penetration, iodine contrast and dose differently from mAs. Photoelectric absorption removes the incident photon and transfers energy to an electron; Compton interaction transfers part of the energy and produces a scattered photon traveling in a different direction. Their differing dependence on material and photon energy underlies spectral CT material discrimination. Coherent scattering changes direction without ionization and contributes less than the other two mechanisms at CT energies. See [AAPM Task Group 291](https://aapm.onlinelibrary.wiley.com/doi/10.1002/mp.14157).
Apply it
A protocol review considers lowering kVp for an iodine-enhanced study in a small patient. Explain that energy-dependent attenuation may increase iodine conspicuity, but penetration and noise must still be assessed. Identify a deflected photon that retains only part of its incident energy as a Compton-scattered photon.
Common pitfall: Treating kVp and mAs as interchangeable dose controls misses their different effects on beam quality. Photoelectric absorption and Compton scattering both attenuate the primary beam, but only the latter leaves a lower-energy scattered photon.
RPT_96.pdf · Siemens Healthineers Academy: CT Basics · ARRT Computed Tomography Examination Content Specifications
16.How do absorbed dose and effective dose differ?
Absorbed dose describes energy deposited per unit mass and is expressed in gray, commonly milligray in CT. Effective dose combines weighted tissue doses to provide a population-based radiation-protection quantity expressed in sievert. It can support broad comparisons between exposure types, but it is not a measured personal risk or a specific organ dose. DLP-to-effective-dose conversion factors depend on examination region and assumptions; they cannot convert a scanner index into an exact individual outcome. Personnel protection also requires controlling access and limiting exposure to patient-generated scatter. During necessary in-room procedures, use appropriate shielding, maximize practical distance and minimize irradiation time; protective garments do not justify placing hands in the primary beam. See the [joint CIRSE/SIR occupational protection guideline](https://pmc.ncbi.nlm.nih.gov/articles/PMC2841268/).
Apply it
A report lists CTDIvol in mGy and an estimated effective dose in mSv. Explain that the quantities answer different questions and should not be compared as if the numerical values described the same physical measurement. For CT-guided intervention, identify the patient as the principal scatter source and position shielding between that source and personnel where practical.
Common pitfall: A value in mSv is not interchangeable with one in mGy. Effective-dose estimates should not be presented as precise predictions of an individual patient's cancer risk. A low patient dose index does not remove the need for personnel protection.
RPT_96.pdf · ARRT Computed Tomography Examination Content Specifications
Image Production52/165 scored questions (approximately 31.52%)
17.How do slip rings, detectors and the DAS enable CT acquisition?
Slip rings allow continuous gantry rotation without repeatedly winding and unwinding electrical connections. Multiple detector rows sample transmitted x-rays across the longitudinal direction, while the data acquisition system converts detector signals into data suitable for reconstruction. Detector configuration determines how signals are collected or combined into channels. Continuous rotation plus table movement permits helical acquisition. The number of physical detector elements, acquired channels and reconstructed images should not be treated as automatically identical.
Apply it
A scanner collects narrow detector-channel data but produces fewer thick review images. Explain that channels may contribute to thicker reconstructions; the displayed image count does not directly reveal the number of independently acquired detector channels.
Common pitfall: Equating reconstructed slice count with detector-row count hides signal grouping and reconstruction choices. Continuous rotation is enabled by slip rings, not by reconstruction software.
18.Which acquisition mode matches spatial or time-dependent information?
Sequential acquisition samples anatomy at discrete table positions; helical acquisition combines rotation with continuous table travel to sample a volume. Wide-area volumetric acquisition can cover a longitudinal region within a rotation. Cine or shuttle approaches repeatedly sample anatomy over time, supporting studies such as perfusion. Dual-energy acquisition adds information from different energy spectra rather than merely repeating the same scan. Choose the mode according to required coverage, temporal sampling and material information.
Apply it
A study must measure contrast passage through a brain region over successive time points. Recognize that repeated time sampling is required; one routine helical pass through the head cannot provide the complete time-attenuation information.
Common pitfall: A fast volumetric scan is not automatically a dynamic study. Temporal assessment requires successive measurements, while dual-energy information requires appropriate spectral acquisition.
Siemens Healthineers Academy: Advanced CT Concepts for Hybrid Imaging Technologists · ACR/RSNA RadiologyInfo: CT Perfusion Imaging of the Head
19.How is multidetector CT pitch calculated?
Multidetector pitch equals table travel per rotation divided by total nominal beam collimation. The denominator is the combined longitudinal acquisition width, not the thickness of one detector channel or reconstructed image. Pitch below one indicates overlapping irradiation; pitch above one indicates greater table travel than beam width per rotation. This geometric definition supports meaningful protocol comparison, but its effect on image quality and dose also depends on interpolation and scanner compensation.
Apply it
A detector configuration provides total nominal beam width 24 mm, and the table advances 30 mm per rotation. Calculate pitch as 30 divided by 24, or 1.25, without using the thickness of a single channel.
Common pitfall: Dividing by one reconstructed slice thickness produces the wrong multidetector pitch. Reconstruction choices do not redefine the physical acquisition width.
RPT_96.pdf · Siemens Healthineers Academy: Advanced CT Concepts for Hybrid Imaging Technologists
20.Why are raw data different from reconstructed image data?
Raw projection data contain attenuation measurements used to calculate images. Reconstructed image data contain the resulting voxel values and can support reformations, rendering and display changes. Retrospective reconstruction from retained raw data can change appropriate reconstruction parameters without another exposure. However, a thick reconstructed image cannot recover all spatial information lost through averaging. Before considering rescanning, determine whether suitable raw data or a sufficiently thin existing image series is still available.
Apply it
A study was acquired with narrow channels but only thick soft-tissue images were initially sent. Request an appropriate thin reconstruction from retained raw data for reformations rather than assuming a second acquisition is necessary.
Common pitfall: Changing display magnification or reformatting thick images cannot recreate missing fine detail. Retrospective reconstruction depends on the information actually acquired and retained.
21.How do filtered backprojection and iterative reconstruction differ?
Filtered backprojection applies mathematical filtering and backprojection to measured data to create an image. Iterative methods repeatedly estimate an image and refine it using data consistency and modeled system or noise behavior. Iterative reconstruction can reduce noise or artifacts, but changes in texture and task performance matter as well as appearance. A smoother image is not automatically more diagnostically accurate. Dose reduction should be evaluated with the reconstruction method and diagnostic task together.
Apply it
A low-dose series reconstructed iteratively looks smoother than a conventional reconstruction. Assess whether the small low-contrast target remains detectable instead of judging suitability only by the lower visible graininess of the image.
Common pitfall: Noise suppression cannot guarantee preservation of every lesion or edge. Reconstruction strength should not be treated as an unlimited substitute for adequate acquisition information.
22.How does slice thickness affect noise and partial-volume averaging?
A reconstructed voxel averages attenuation within its volume. Thick slices combine more longitudinal information, generally reducing noise but increasing averaging of small structures and mixed tissues. Thin slices improve longitudinal detail and reduce partial-volume effects, while usually appearing noisier at unchanged acquisition conditions. Choose thickness according to the feature being evaluated. A small dense structure mixed with adjacent low-attenuation tissue may have an intermediate measured CT number rather than its true material attenuation.
Apply it
A tiny calcification appears faint on thick images but clear on a thin reconstruction from the same acquisition. Explain that reduced partial-volume averaging improves its visibility, despite the thin images having greater background noise.
Common pitfall: The least noisy slice is not always the most informative. Thick averaging can hide small structures or distort measured attenuation even when the image looks smooth.
Siemens Healthineers Academy: CT Essentials—Reconstruction Parameters Part 2
23.What is the difference between reconstruction thickness and interval?
Thickness describes the longitudinal extent represented by each reconstructed image; interval describes the distance between successive image centers. When interval is smaller than thickness, images overlap. Overlap can improve continuity in reformations and rendering without another acquisition. It does not make each individual image thinner or create new acquired resolution. An interval greater than thickness creates gaps in the reconstructed series that can omit small features between displayed sections.
Apply it
A series uses 2-mm thickness and 1-mm interval. Recognize overlapping reconstructions, useful for continuous reformations. Changing only the interval to 0.5 mm increases sampling density and image count without making each image 0.5 mm thick.
Common pitfall: Calling the interval the slice thickness confuses sampling with averaging. More overlapping images do not automatically add radiation exposure or improve intrinsic acquired resolution.
Siemens Healthineers Academy: Advanced CT Concepts for Hybrid Imaging Technologists
24.How do display field of view and matrix determine pixel size?
For a square reconstruction, in-plane pixel size equals display field of view divided by matrix dimension. Reducing reconstruction field of view at the same matrix produces smaller pixels, provided the anatomy lies within acquired coverage. Display zoom simply enlarges existing pixels and does not add spatial information. Scan field of view defines acquisition-related coverage, while display field of view selects the reconstructed region. Pixel sampling is one contributor to resolution, alongside detector, focal-spot and reconstruction factors.
Apply it
With a 512 matrix and 256-mm display field of view, calculate 0.5-mm pixels. A 128-mm reconstruction field gives 0.25-mm pixels, whereas enlarging the first image on the monitor leaves its original sampling unchanged.
Common pitfall: Monitor magnification is not equivalent to reconstructing smaller pixels. A small display field cannot restore anatomy or measurements absent from the acquired data.
Siemens Healthineers Academy: Advanced CT Concepts for Hybrid Imaging Technologists
25.How do window width and level control displayed contrast?
Window level sets the center of the displayed attenuation range, while window width sets its span. Approximate lower and upper limits are level minus half the width and level plus half the width. Narrow windows make small attenuation differences more conspicuous but saturate a larger proportion of tissues. Wide windows display a broader range with less visible contrast between nearby values. Window changes alter presentation rather than the stored Hounsfield values or the acquired radiation exposure.
Apply it
A soft-tissue display uses level 50 HU and width 300 HU. Calculate approximate limits of −100 and 200 HU. Narrowing the width emphasizes nearby soft-tissue differences while clipping more very low and very high values.
Common pitfall: Changing the window cannot correct photon noise or recover lost anatomy. A saturated display value does not mean the underlying stored CT number has changed.
Siemens Healthineers Academy: CT Essentials—Reconstruction Parameters Part 2
26.What do Hounsfield values and ROI statistics reveal?
Hounsfield units express attenuation relative to water: water is approximately zero and air approximately −1000 under the conventional scale. An ROI mean summarizes included attenuation values; its standard deviation describes their spread. In a uniform phantom, standard deviation is a useful noise measure. In heterogeneous patient tissue, it also reflects actual tissue variation. Keep the ROI away from edges, mixed structures and artifacts when estimating a material's attenuation or comparing image noise.
Apply it
An ROI intended to measure fluid overlaps its enhancing wall. Reposition it within homogeneous fluid before interpreting the mean. For a noise comparison, use comparable uniform phantom regions rather than different heterogeneous organs.
Common pitfall: A high ROI standard deviation is not necessarily pure noise. Tissue heterogeneity, partial-volume averaging and artifacts can increase spread and bias the mean.
Siemens Healthineers Academy: CT Basics · AAPM CT Image Quality—A Summary
27.How does the square-root relationship guide noise calculations?
Under quantum-noise-dominated conditions with other factors unchanged, image noise varies approximately inversely with the square root of mAs. Doubling mAs reduces noise to about 71% of its original value, rather than halving it. Halving noise requires approximately four times the mAs. These calculations assume comparable reconstruction, thickness, patient attenuation and tube voltage. They describe foundational behavior and should not be generalized across changing iterative algorithms or automatic exposure-control settings.
Apply it
A uniform phantom has noise 16 HU at 100 mAs. Predict approximately 8 HU at 400 mAs when kVp, thickness, kernel and all other relevant conditions remain unchanged under the stated quantum-noise assumption.
Common pitfall: A linear noise calculation underestimates the exposure increase needed. Changing reconstruction or slice thickness invalidates a comparison attributed solely to mAs.
28.Which reconstruction kernel suits fine edges or low-contrast tissue?
A sharp kernel emphasizes high-frequency detail and improves visibility of small edges, typically at the cost of greater image noise. A smoother kernel suppresses high-frequency variation and can improve assessment of low-contrast soft tissue, while blurring fine structures. These are different diagnostic tasks, so one reconstruction may not serve both well. When the acquisition permits, complementary bone or lung and soft-tissue series can answer different questions without another exposure.
Apply it
A fracture study also needs assessment of adjacent soft tissue. Reconstruct a sharp series for cortical detail and a smoother series for soft-tissue review from the same suitable raw data, rather than forcing one kernel to serve both.
Common pitfall: The sharpest image is not universally best. Increased edge detail can come with noise that makes subtle low-contrast differences harder to assess.
Siemens Healthineers Academy: Advanced CT Concepts for Hybrid Imaging Technologists
29.Why is temporal resolution different from spatial resolution?
Spatial resolution concerns separating nearby structures; temporal resolution concerns limiting blur from motion during the data contributing to an image. Smaller pixels or thinner slices cannot by themselves freeze a moving coronary artery. Rotation speed, acquisition geometry and ECG-based selection affect cardiac temporal performance. Breathing and patient movement also produce inconsistency among projections. Match the solution to the cause: improve relevant time sampling or motion control rather than simply increasing spatial sampling.
Apply it
Coronary edges remain blurred despite thin slices and a small display field of view. Identify cardiac motion as a temporal problem and review acquisition and ECG synchronization, rather than assuming further pixel-size reduction will resolve it.
Common pitfall: Fine spatial sampling does not compensate for motion occurring during acquisition. A sharper kernel can emphasize motion edges without restoring the structure's true position.
Siemens Healthineers Academy: Advanced CT Concepts for Hybrid Imaging Technologists · ACR/RSNA RadiologyInfo: Coronary CTA
30.How do multiplanar reformations improve anatomic assessment?
Multiplanar reformation resamples a reconstructed volume into coronal, sagittal or oblique planes. It helps follow structures whose course is difficult to appreciate on isolated axial images, such as the spine or a long bone. Thin, appropriately sampled source images improve continuity and reduce stair-step appearance. Reformations use existing image data and do not independently expose the patient. Their quality remains limited by acquisition resolution, motion and the source reconstruction.
Apply it
An oblique fracture line is difficult to follow on axial images. Create coronal and sagittal reformations from the thin source series to evaluate its extension and alignment without obtaining another CT acquisition.
Common pitfall: Reformation cannot erase motion or recreate detail averaged out of thick source images. Poor source sampling can produce convincing-looking but inaccurate step-like boundaries.
Siemens Healthineers Academy: Advanced CT Concepts for Hybrid Imaging Technologists · ACR/RSNA RadiologyInfo: CT Scan of the Spine
31.When are MIP and volume rendering useful?
Maximum-intensity projection displays the highest attenuation encountered along each viewing ray, making enhanced vessels or dense structures conspicuous. It can also superimpose calcium or bone over a vessel and obscure lower-attenuation information. Volume rendering combines voxel contributions using selected color and opacity assignments to show three-dimensional relationships. Both are presentations of source data rather than independent proof of a finding. Review source images and suitable reformations whenever overlap or rendering choices could mislead.
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A CTA MIP appears to show an interrupted vessel next to dense bone. Inspect thin source images and change slab or viewing orientation before interpreting the interruption, because high-attenuation overlap can obscure the lumen.
Common pitfall: A striking three-dimensional display can hide relevant structures through overlap or opacity settings. Rendered appearance must be checked against the source images.
Siemens Healthineers Academy: Advanced CT Concepts for Hybrid Imaging Technologists · ACR/RSNA RadiologyInfo: CT Angiography
32.How do beam hardening and metal artifacts alter images?
As a polychromatic beam passes through matter, preferential loss of lower-energy photons changes its effective spectrum. This beam hardening can cause shading, cupping or streaks that do not represent true tissue attenuation. Metal adds severe attenuation, photon starvation and other inconsistencies, so its artifacts are not explained by one mechanism alone. Appropriate positioning, acquisition choices and artifact-reduction reconstruction can help, but the underlying source images and remaining distortion still require careful evaluation.
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Dark bands cross soft tissue between dense structures, while a hip prosthesis produces more extensive streaking. Recognize attenuation-related artifacts and review available reduction reconstructions before treating every dark region as a true tissue abnormality.
Common pitfall: Artifact-reduction software can change the appearance of nearby anatomy and introduce new distortions. A cleaner-looking reconstruction should not replace evaluation of residual limitations.
Siemens Healthineers Academy: CT Basics · ARRT Computed Tomography Examination Content Specifications
33.How do rings and phantom tests distinguish equipment problems?
A persistent detector-response inconsistency can map into a ring artifact in rotating CT geometry. A uniform phantom helps distinguish a repeatable equipment pattern from patient anatomy, motion or heterogeneous tissue. Compare the pattern across appropriate tests and follow equipment-quality procedures rather than repeatedly scanning patients to investigate it. Phantom evaluation also permits consistent assessment of noise, uniformity and CT-number stability. Trends are more informative when test setup and reconstruction conditions remain comparable.
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Concentric shading appears in unrelated patient studies and persists in a uniform phantom. Identify an equipment or calibration concern and initiate the relevant quality-control response rather than attributing the pattern to a shared patient finding.
Common pitfall: Repeating patient examinations does not diagnose a reproducible scanner defect efficiently. Changing phantom technique each time can conceal whether image-quality performance has actually changed.
Siemens Healthineers Academy: CT Basics · AAPM CT Image Quality—A Summary · ARRT Computed Tomography Examination Content Specifications
34.What establishes DICOM storage interoperability?
DICOM defines structured information and services for medical imaging communication. Interoperability depends on compatible service-object pair classes, transfer syntaxes and service roles, rather than a generic statement that both systems support DICOM. A conformance statement describes implemented capabilities and limitations. Successful transmission also differs from confirming correct patient association and complete availability in the archive. Evaluate the specific objects being sent and the receiving system's declared support when troubleshooting storage.
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A workstation sends ordinary CT images successfully but fails with a different image-object type. Compare sender and receiver conformance statements for the affected SOP class and transfer syntax instead of assuming all DICOM objects are interchangeable.
Common pitfall: A network connection alone does not establish image-service compatibility. Broad DICOM branding cannot guarantee support for every object, encoding or service role.
35.How must CT data be de-identified for secondary use?
De-identification must address identifying attributes and any identifying information embedded in pixel data or related graphics. Removing Patient Name alone is insufficient. DICOM confidentiality profiles and options define treatments for different information categories and permitted retention needs. Under the Clean Pixel Data Option, identifying burned-in text must be removed from stored pixel values; a removable overlay or display shutter is insufficient. Ordinary CT images may lack burned-in names, but exported secondary images still require evaluation.
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A teaching export has anonymized headers but retains a patient's name burned into a screenshot image. Remove the identifying stored pixels and inspect the complete export before sharing; covering the name with an overlay is insufficient.
Common pitfall: Header anonymization does not guarantee pixel confidentiality. A covering graphic may disappear in another viewer, exposing identifying text that remains in the stored image.
6.9 Attribute Confidentiality Profiles · E.3 Basic Application Level Confidentiality Options
Procedures71/165 scored questions (approximately 43.03%)
36.Why is noncontrast head CT useful for acute intracranial bleeding?
Head CT rapidly depicts intracranial structures and is useful for assessing acute bleeding, mass effect and traumatic injury. Noncontrast acquisition permits evaluation of intrinsic attenuation without administered iodine. Identify the third ventricle between the paired thalami and the posterior limb of the internal capsule along the lateral thalamic border; these relationships orient deep-brain review. Assess ventricular compression and displacement with surrounding anatomy when evaluating mass effect. Brain and bone presentations answer different questions. A normal noncontrast examination does not establish normal perfusion or exclude every early ischemic abnormality. The anatomic relationships are illustrated in [University of Texas Neuroanatomy Online](https://nba.uth.tmc.edu/neuroanatomy/L7/Lab07p17_index.html).
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An emergency request asks about intracranial hemorrhage. Review noncontrast brain images for bleeding and mass effect, identify the thalami and intervening third ventricle, and compare ventricular position and caliber across adjacent sections rather than interpreting one isolated image.
Common pitfall: No visible hemorrhage is not equivalent to normal cerebral blood flow. Patient rotation can complicate apparent symmetry, so assess suspected displacement in relation to the cranial midline and neighboring images.
ACR/RSNA RadiologyInfo: Head CT · ACR/RSNA RadiologyInfo: CT Perfusion Imaging of the Head
37.How does brain perfusion CT differ from routine head CT?
Perfusion CT repeatedly measures changes in attenuation as intravenous contrast passes through cerebral tissue. Analysis provides information about blood delivery and passage through the sampled brain region. This is physiologic information rather than only a static anatomic image or a view of a large artery. Repeated time sampling, motion control and correctly coordinated contrast administration are therefore central. Coverage and interpretive limitations depend on the acquisition and processing used; perfusion maps require clinical and anatomic correlation.
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A routine head CT shows no hemorrhage, but the clinical team needs information about cerebral tissue perfusion. Explain why a dynamic contrast acquisition supplies a different measurement from repeating another static noncontrast image.
Common pitfall: A patent large artery does not prove normal tissue perfusion. A single enhanced image cannot substitute for the time-dependent measurements used to construct perfusion information.
38.Which hearing-loss pattern points toward temporal-bone CT?
Temporal-bone CT is particularly useful for detailed evaluation of bony structures involved in conductive hearing loss. Conductive loss concerns transmission of sound through the external or middle ear, whereas sensorineural loss concerns the inner ear or auditory neural pathway. This distinction helps explain why high-resolution bone CT and MRI are not interchangeable. Fine source sampling and appropriate bone reconstruction support assessment of small temporal structures, but CT does not replace MRI when the principal question concerns relevant neural soft tissue.
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An adult has conductive hearing loss and suspected ossicular abnormality. Identify dedicated temporal-bone CT as a study suited to the bony middle-ear question rather than choosing a routine thick-slice brain examination.
Common pitfall: Treating all hearing loss as one indication ignores the affected pathway. Routine head CT may not supply the detailed temporal-bone assessment the clinical question requires.
ACR/RSNA RadiologyInfo: Hearing Loss and/or Vertigo · Siemens Healthineers Academy: Advanced CT Concepts for Hybrid Imaging Technologists
39.How should orbital and facial CT separate bone and soft-tissue questions?
Orbital and maxillofacial studies involve closely adjacent bones, air spaces and soft tissues. The lamina papyracea separates the ethmoid air cells from the orbit and forms the thin medial orbital wall. Recognizing this boundary helps localize a medial-wall fracture or extension of adjacent sinus disease. A sharp reconstruction reveals cortical detail, while complementary soft-tissue images evaluate neighboring tissue. Coronal reformations show the orbital–ethmoid relationship clearly, and requested anatomy determines coverage. Contrast use follows the soft-tissue or vascular indication rather than being assumed necessary for every bone assessment. See [UConn's sinus CT teaching material](https://health.uconn.edu/graduate-medical-education/wp-content/uploads/sites/20/2024/05/FESS-Elective-3_24.pdf).
Apply it
A facial-trauma study shows a suspected break in the medial orbital wall. Locate the lamina papyracea between orbital contents and ethmoid air cells, then review thin bone images, coronal reformations and complementary soft-tissue images for the full injury.
Common pitfall: A sharp bone series can make soft tissue difficult to assess. A routine head-study name does not guarantee dedicated coverage or reconstruction of every facial structure.
ACR/RSNA RadiologyInfo: Head CT · Siemens Healthineers Academy: Advanced CT Concepts for Hybrid Imaging Technologists · ARRT Computed Tomography Examination Content Specifications
40.Why is sinus CT valuable for surgical planning?
Sinus CT depicts air-filled cavities, bony boundaries and drainage pathways. The ostiomeatal complex serves drainage of the maxillary, frontal and anterior ethmoid sinuses; obstruction can therefore affect several connected regions. Recognize the lamina papyracea at the orbit–ethmoid boundary and the cribriform plate and ethmoid roof at the skull-base boundary. Coronal images help map these relationships and asymmetry; thin source data support additional planes. Surgical planning requires identifying vulnerable boundaries and drainage anatomy, rather than simply documenting opacity. See [UConn's FESS and sinus CT teaching material](https://health.uconn.edu/graduate-medical-education/wp-content/uploads/sites/20/2024/05/FESS-Elective-3_24.pdf).
Apply it
Before sinus surgery, trace the ostiomeatal drainage region and examine the lamina papyracea and ethmoid roof. Use coronal reformations to recognize orbital and skull-base boundaries and describe where disease or anatomic variation affects the operative route.
Common pitfall: Detecting opacity alone does not complete surgical mapping. Thick routine head images may show disease while inadequately demonstrating small bony relationships or asymmetry.
ACR/RSNA RadiologyInfo: CT of the Sinuses · Siemens Healthineers Academy: Advanced CT Concepts for Hybrid Imaging Technologists
41.How do spine anatomy and reformations clarify fracture and alignment?
A typical vertebra has a body and an arch; paired pedicles connect the body to the arch, and laminae form its posterior portion. The body and arch enclose the vertebral canal. On axial images, distinguish anterior body injury from posterior-element injury and follow the canal boundary. Sagittal reformations show vertebral height and alignment across levels, while coronal and oblique views clarify fracture extension. Thin source data support these tasks. Positioning must preserve clinically required immobilization, and strong bony assessment does not fully characterize every cord or ligament injury. See [Texas Tech's back anatomy tables](https://anatomy.ttuhscep.edu/schemes/back_tables.html).
Apply it
An axial cervical image shows a fracture near a pedicle. Identify the body, pedicle, lamina and canal, then use reformations to determine extension into adjacent elements and assess alignment while preserving immobilization.
Common pitfall: One axial view can underrepresent a fracture's extent. Clear bone images do not automatically exclude injuries whose principal abnormality lies in spinal soft tissue.
42.What makes CT myelography a distinct spine procedure?
Myelography introduces a suitable contrast agent into the subarachnoid space, generally through a lumbar puncture. Subsequent CT can depict the contrast-filled space around the spinal cord and nerve roots in detail. This differs from intravenous enhancement of spinal tissues and from routine noncontrast bone CT. Route-specific agent selection and coordinated procedural care are essential. The indication is assessment of structures outlined by intrathecal contrast, often when other imaging is inadequate or cannot be performed.
Apply it
A patient proceeds from fluoroscopic myelography to CT. Recognize that the spinal canal's contrast appearance comes from intrathecal administration and tailor the CT coverage to the requested postmyelogram assessment.
Common pitfall: Intravenous contrast does not reproduce a myelogram's compartmental opacification. Intrathecal administration requires an appropriate formulation and cannot be inferred from an agent's general iodinated identity.
ACR/RSNA RadiologyInfo: Myelography · ACR Manual on Contrast Media
43.How does musculoskeletal CT support complex fracture planning?
Complex fractures require assessment of cortical breaks, fragment position and relationships to an articular surface. Thin source data, a suitable bone reconstruction and multiplanar views provide complementary information. Three-dimensional rendering can communicate overall fragment relationships, but overlap or opacity settings may hide a small component. Diagnostic review therefore remains anchored in source images and reformations. Additional angiographic or soft-tissue questions require their own contrast and timing considerations rather than being answered automatically by the bone study.
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An intra-articular lower-extremity fracture needs operative planning. Review thin bone images and reformations for joint-surface involvement, then use a three-dimensional presentation to communicate fragment relationships without relying on the rendered view alone.
Common pitfall: A three-dimensional image can omit small fragments through rendering settings. Excellent cortical detail does not establish that associated vascular or soft-tissue questions have been answered.
Siemens Healthineers Academy: Advanced CT Concepts for Hybrid Imaging Technologists · ARRT Computed Tomography Examination Content Specifications
44.How does postarthrogram CT differ from intravenous enhancement?
Postarthrogram CT evaluates a joint after contrast has been introduced into its joint space. Direct injection both opacifies and distends that compartment, separating and outlining small internal structures such as cartilage and the labrum. This differs from blood-borne tissue enhancement after an intravenous injection. The targeted joint determines coverage and useful planes. Fine spatial sampling supports assessment of contrast-outlined interfaces. A routine enhanced limb CT does not reproduce direct joint distention and opacification.
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A request specifies postarthrogram shoulder CT. Confirm the preceding intra-articular procedure and create joint-focused reconstructions to assess contrast-outlined internal structures rather than substituting a routine intravenous contrast shoulder acquisition.
Common pitfall: Enhancing tissue around a joint is different from filling and distending its joint space. An intravenous injection cannot be assumed equivalent to direct intra-articular contrast administration.
Direct Arthrography · ARRT Computed Tomography Examination Content Specifications · ACR Manual on Contrast Media
45.How do neck soft-tissue and arterial studies differ?
A soft-tissue neck study evaluates structures such as the airway and surrounding tissues; a carotid CTA focuses on arterial anatomy and requires appropriately timed arterial enhancement. Both may use intravenous iodine, but their principal targets and timing are different. Trace each common carotid artery into its internal and external branches rather than classifying a vessel from one cross section alone. The internal jugular vein commonly lies anterolateral to the carotid artery, with positional variation; following continuity helps prevent vessel misidentification. This relationship is documented in a [primary carotid-sheath anatomy study](https://pubmed.ncbi.nlm.nih.gov/18595678/). Vascular reformations support lumen assessment.
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For suspected carotid narrowing, follow the artery through the bifurcation on thin arterial images and reformations. Distinguish the adjacent jugular vein by its course and phase-dependent opacification instead of assuming every rounded enhancing structure is arterial.
Common pitfall: Any enhanced neck scan is not automatically a carotid angiogram. Anatomic position varies, so a single positional rule cannot replace tracing vessel continuity.
ACR/RSNA RadiologyInfo: CT Angiography · ARRT Computed Tomography Examination Content Specifications
46.Which anatomy and reconstruction priorities distinguish lung from mediastinal assessment?
Lung assessment depends on fine air–tissue interfaces, making thin images and high-detail reconstruction useful. Mediastinal assessment emphasizes soft tissues and may require a smoother presentation and indication-specific contrast. Recognize the carina as the tracheal bifurcation separating the right and left main bronchi, then follow the airways into the lungs. This landmark anchors central-airway review and localization of nearby abnormalities. See [Texas Tech's carina teaching example](https://anatomy.ttuhscep.edu/cardiovascular_system/sup_med_questions/sup_med_15_feedback.html). Complementary reconstructions can serve both regions. Low-dose screening has a different purpose from symptomatic vascular imaging and does not establish diagnostic pulmonary arterial enhancement.
Apply it
A chest study needs interstitial lung and central-airway assessment. Review thin lung images, identify the carina and trace both main bronchi; use a complementary soft-tissue series to assess nearby mediastinal tissue.
Common pitfall: A lung-focused or screening examination cannot be assumed to answer a vascular question. Sharp reconstruction helps fine interfaces but can impair low-contrast soft-tissue assessment.
ACR/RSNA RadiologyInfo: Chest CT · Siemens Healthineers Academy: Advanced CT Concepts for Hybrid Imaging Technologists
47.Why must pulmonary CTA target pulmonary arterial enhancement?
Pulmonary CTA evaluates the pulmonary arterial lumen for emboli, so acquisition must coincide with adequate enhancement of the pulmonary circulation. Bolus tracking obtains monitoring images during the diagnostic contrast injection and measures attenuation in a target-vessel region of interest (ROI). When attenuation reaches the configured threshold, the system initiates acquisition after the configured post-trigger delay. For pulmonary CTA, place the ROI within the main pulmonary arterial blood pool, avoiding the vessel wall, thrombus, adjacent vessels, and partial volume effects. Threshold definitions, including absolute attenuation versus increase above baseline, and subsequent delays depend on the scanner and protocol. A timing bolus instead uses a separate small test injection and serial measurements to produce a time-attenuation curve. The measured contrast arrival and peak enhancement inform the timing of the subsequent diagnostic injection and acquisition. Neither method makes routine delayed enhanced chest CT equivalent to pulmonary CTA.
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Compare two workflows. One monitors a main pulmonary artery ROI during the full diagnostic injection and starts acquisition after a threshold and delay: this is bolus tracking. The other measures a time-attenuation curve after a separate small injection and uses that curve to plan the diagnostic scan: this is a timing bolus. In either workflow, review pulmonary arterial opacification and respiratory motion before accepting an apparent low-attenuation region as an embolus.
Common pitfall: A tracking ROI over the vessel wall or thrombus can underestimate blood-pool enhancement and delay or prevent triggering. A threshold crossing identifies a configured enhancement event; it does not automatically identify peak enhancement throughout every pulmonary artery. Incorrect timing, mixing of enhanced and unenhanced blood, and motion can mimic or obscure filling defects. Reformating poorly opacified images cannot restore missing vascular enhancement.
ACR/RSNA RadiologyInfo: CT Angiography · ARRT Computed Tomography Examination Content Specifications
48.How does aortic CTA support assessment of dissection?
Aortic dissection involves blood separating layers of the aortic wall, creating a false lumen alongside the true lumen. The intervening dissection flap is a defining image-review finding. Arterially timed CTA and multiplanar reformations help follow the flap longitudinally, determine whether the ascending aorta is involved, and assess extension into branch vessels. Branch compromise matters because narrowing or obstruction can reduce blood supply to organs or limbs. Assess branch origins and luminal patency rather than assuming that visible contrast excludes impaired perfusion. Cardiac motion at the aortic root and ascending aorta can produce blurred or duplicated boundaries resembling a flap. ECG synchronization coordinates acquisition or reconstruction with the cardiac cycle to reduce this motion artifact. Within suspected acute aortic syndrome, a noncontrast acquisition has a distinct purpose: identifying intrinsically hyperattenuating blood within the aortic wall, often crescentic, that supports intramural hematoma. Intramural hematoma may lack the classic flap and two flowing lumens. Acquisition phases must answer defined diagnostic questions rather than be prescribed universally.
Apply it
Compare a sharp flap that continues through contiguous source images and reformations into a narrowed branch artery with a short, blurred line confined to the root on a nongated scan. The continuous flap and branch extension support dissection; the isolated root finding remains uncertain because pulsation can mimic a flap. Promptly communicate the suspicious finding and technical uncertainty. ECG-synchronized assessment can reduce root-motion ambiguity, while appropriate coverage establishes longitudinal and branch-vessel involvement.
Common pitfall: Do not diagnose or dismiss dissection from a single linear root finding. Multiplanar continuity and branch relationships provide stronger evidence, but clinically important uncertainty still requires resolution. Bright luminal contrast can make subtle wall hematoma harder to recognize, explaining the separate value of noncontrast imaging. Additional phases cannot replace missing anatomic coverage, and reformations alone cannot reliably eliminate motion already present in the acquired data.
ACR/RSNA RadiologyInfo: CT Angiography · ARRT Computed Tomography Examination Content Specifications
49.How do coronary CTA and TAVR planning differ in targets, coverage and reconstruction?
Coronary CTA emphasizes moving coronary arteries, their lumen and plaque, requiring arterial enhancement, ECG coordination and vessel-focused reconstructions. TAVR planning requires aortic root and annular measurements for valve sizing plus vascular-access assessment. Define the annular plane through the lowest attachment points of the three aortic cusps and use double-oblique reformations for area, perimeter and diameter measurements. Cardiac phase also matters: annular dimensions are generally largest in systole, so acquisition must include systolic information. Review available phases and select the phase showing the largest annular dimensions with adequate image quality; no single ECG percentage is appropriate for every patient. Root assessment also includes coronary ostial heights. Broader aortic and iliofemoral coverage evaluates access caliber, calcification and tortuosity. These measurement principles follow the [SCCT TAVI/TAVR consensus](https://cdn.ymaws.com/scct.org/resource/resmgr/docs/guidelines/scct_tavi_tavr_ecd_2019.pdf).
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For coronary-stenosis assessment, prioritize coronary enhancement, motion control and vessel reconstructions. For transfemoral TAVR planning, review cardiac phases, align the annular plane in each phase being compared, and select the largest adequately visualized annular dimensions. For example, if properly aligned, diagnostic images show an annular area of 480 mm² in systole and 440 mm² in diastole, use the larger systolic measurement for the sizing assessment. Include the root, aorta, iliac arteries and common femoral access vessels.
Common pitfall: Correct annular-plane alignment alone does not establish an appropriate sizing measurement. Selecting a smaller diastolic annulus can underestimate its maximum dimensions and cause valve undersizing. Conversely, motion-blurred boundaries cannot provide reliable measurements merely because they occur in systole. Thin routine chest images do not establish adequate cardiac temporal resolution, and diagnostic root images do not establish suitability of an unexamined vascular-access route.
ACR/RSNA RadiologyInfo: Coronary CTA · ARRT Computed Tomography Examination Content Specifications
50.What does coronary calcium scoring establish?
Coronary calcium scoring uses a noncontrast cardiac CT examination to measure calcified coronary plaque burden. It provides information different from contrast-enhanced assessment of the arterial lumen. A calcium score of zero does not demonstrate the absence of all coronary plaque because noncalcified plaque is outside the score's target. Interpret the result according to the examination's purpose and the patient's clinical assessment. Do not convert a noncontrast calcium measurement into a comprehensive coronary angiographic conclusion.
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A patient interprets a zero calcium score as proof that no coronary plaque exists. Explain that the examination detects calcified plaque; assessment of noncalcified plaque and lumen involves a different clinical and imaging question.
Common pitfall: Zero detected calcium is not identical to zero atherosclerosis. Calcium scoring cannot be treated as a contrast angiogram or a complete exclusion of coronary disease.
ACR/RSNA RadiologyInfo: Cardiac CT for Calcium Scoring · ACR/RSNA RadiologyInfo: Coronary CTA
51.How do prospective and retrospective ECG approaches differ?
Prospective ECG-triggered acquisition targets a planned portion of the cardiac cycle, while retrospective ECG synchronization associates continuously acquired data with cardiac phase for later reconstruction. Prospective approaches can restrict exposure, whereas retrospective approaches offer broader phase selection but may involve greater exposure. Rhythm, the diagnostic task and scanner capabilities affect suitability. Neither label alone guarantees motion-free images or a particular dose; examine the actual acquisition window, modulation and reconstruction requirements.
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A cardiac protocol needs only anatomic images at a suitable phase in a patient with a stable rhythm. Explain why a restricted prospective acquisition may avoid exposure for phases that do not contribute to that task.
Common pitfall: Prospective acquisition is not universally suitable for every rhythm or functional question. Retrospective synchronization does not eliminate the need to review dose and phase requirements.
ACR/RSNA RadiologyInfo: Coronary CTA · RPT_96.pdf · ARRT Computed Tomography Examination Content Specifications
52.How can CT esophagram assess suspected esophageal leakage?
For suspected esophageal leakage, administered enteric contrast must opacify the relevant esophageal lumen during imaging. Contrast outside that lumen demonstrates leakage; surrounding mediastinal or pleural findings help assess its consequences. IV contrast enhances tissues but does not substitute for luminal opacification. Water-soluble iodinated contrast is generally preferred initially when perforation is suspected because extraluminal barium can cause serious complications. Assess swallowing ability and aspiration risk before administration; low- or iso-osmolar agents have lower aspiration-related pulmonary risk than hyperosmolar agents. A negative examination with poor opacification cannot exclude a leak, and a small or contained leak may remain undetected despite apparently adequate imaging. Persistent suspicion warrants further directed evaluation. The [AATS esophagography primer](https://www.aats.org/tsra-primer-contrast-esophagography-and-post-esophagectomy-care) explains agent selection and false-negative limitations.
Apply it
A patient develops chest symptoms after an esophageal procedure. For an ordered CT leak assessment, review procedure location, ability to swallow, aspiration precautions and any fasting instructions; coordinate the ordered small-volume enteric contrast administration with imaging. Trace contrast within the lumen and inspect for extraluminal escape at the suspected site. Do not apply a routine fluoroscopic swallow volume or a prolonged oral-preparation schedule automatically to an urgent CT study.
Common pitfall: A negative result is weak evidence when contrast never reached the suspected segment. Water-soluble contrast does not eliminate aspiration risk, and a routine enhanced chest CT cannot establish that an adequate luminal leak assessment occurred.
ARRT Computed Tomography Examination Content Specifications · ACR Manual on Contrast Media
53.How do selected organ questions determine useful CT phases?
Phases must answer organ-specific questions. For a liver lesion in an appropriate HCC-risk population, late arterial images assess enhancement greater than liver, while portal venous or delayed images assess a subsequent relative reduction to hypoenhancement, termed washout; one phase cannot establish that temporal pattern. These features require the complete applicable diagnostic criteria, rather than diagnosing every enhancing lesion as HCC. See [ACR LI-RADS Core](https://www.acr.org/-/media/ACR/Files/RADS/LI-RADS/LI-RADS-2018-Core.pdf). For suspected chronic pancreatitis, a pancreatic parenchymal phase emphasizes pancreatic enhancement, while portal venous images add assessment of complications and surrounding tissues; recognize calcifications, atrophy and ductal abnormalities. See [ACR Chronic Pancreatitis](https://acsearch.acr.org/list/TopicNarrativePdf?topicId=352). For an indeterminate adrenal nodule, unenhanced attenuation assesses lipid-rich composition; enhanced and delayed images permit washout assessment when indicated. A homogeneous nodule at or below 10 HU on unenhanced CT supports a lipid-rich adenoma, whereas that cutoff cannot be applied to enhanced images. See [ACR Adrenal Mass Evaluation](https://acsearch.acr.org/list/TopicNarrativePdf?topicId=30). In stable renal trauma, arterial images assess vascular injury or active bleeding, nephrographic images demonstrate contusions and lacerations, and delayed excretory images reveal collecting-system leakage. These examples illustrate phase purposes, not universal acquisition delays.
Apply it
For renal trauma, explain why a parenchymal laceration on nephrographic images does not establish whether urine is leaking: delayed excreted contrast supplies that distinction. For adrenal characterization, recognize that a 20-HU measurement on an enhanced image cannot answer the unenhanced lipid question. For liver review, compare the same lesion with surrounding liver across phases rather than labeling one low-attenuation image as washout.
Common pitfall: More phases do not automatically improve diagnosis. Patient circulation and renal excretion affect phase adequacy, and each added acquisition requires a defined benefit. Liver washout appearance and quantitative adrenal washout are different assessments; a delayed adrenal measurement alone is insufficient for a washout calculation.
ACR/RSNA RadiologyInfo: Abdominal and Pelvic CT · RPT_96.pdf · EAU Guidelines on Urological Trauma - UROGENITAL TRAUMA GUIDELINES · ARRT Computed Tomography Examination Content Specifications
54.How does CT urography depict the urinary tract?
CT urography evaluates renal tissues and contrast passing into the collecting systems, ureters and bladder. Trace the collecting system into the renal pelvis and ureter, then follow each ureter to the bladder; a short unopacified segment is not equivalent to an absent ureter. Proximally, the ureters descend anterior to the psoas muscles, useful landmarks for identifying their course on axial images and reformations. See [Texas Tech's CT nephrolithiasis anatomy case](https://anatomy.ttuhscep.edu/clinicalcases/nephrolithiasis/nephrolithiasis.html). Excretory information differs from early vascular enhancement or noncontrast stone imaging. Coverage, timing and breath control influence whether the intended urinary structures are adequately shown.
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A referral concerns collecting systems and ureters. On excretory images, identify renal pelvis continuity and trace the ureters anterior to the psoas toward the bladder using thin images and coronal reformations. Document limitations where opacification or motion prevents assessment.
Common pitfall: Contrast-enhanced kidney images alone do not prove that the ureters are adequately assessed. Renal excretion varies, and one universal delay cannot ensure complete opacification in every patient.
55.Which initial CT approach fits uncomplicated suspected stone disease?
For a nonpregnant adult with acute flank pain, suspected stone disease and no or remote stone history, ACR rates CT abdomen and pelvis without intravenous contrast as usually appropriate. Noncontrast assessment depicts urinary calculi without requiring contrast administration or an excretory phase. This recommendation belongs to that defined clinical variant. Pregnancy changes the initial imaging hierarchy, and an inconclusive noncontrast examination creates a different decision than the initial straightforward stone scenario.
Apply it
A nonpregnant adult has new acute flank pain and suspected urinary calculus with no prior stone diagnosis. Identify noncontrast abdomen and pelvis CT as the usually appropriate CT option for this specified initial presentation.
Common pitfall: A stone protocol should not be applied indiscriminately to every flank-pain patient. Pregnancy and an inconclusive prior study require consideration of different clinical variants.
56.How do anatomic localization and pregnancy affect suspected appendicitis imaging?
The appendix arises from the posteroinferior cecum near the ileocecal region. Identify the cecum and trace the appendix from its origin instead of assuming any right-lower-quadrant tubular structure is the appendix; its distal position varies. Multiplanar review helps follow continuity and surrounding abnormalities. See [Texas Tech's intestinal anatomy tables](https://anatomy.ttuhscep.edu/gastrointestinal_system/peritoneum_tables.html). For right lower quadrant pain with fever and leukocytosis in a nonpregnant adult, ACR rates CT abdomen and pelvis with IV contrast as usually appropriate. In pregnancy, ultrasound and MRI without IV contrast are usually appropriate initial options, with CT potentially appropriate according to circumstances.
Apply it
For an adult CT appendicitis assessment, locate the cecum and trace the appendix on axial and coronal images, keeping the full abdomen and pelvis question in view. For a pregnant patient with the same symptoms, recognize ultrasound or noncontrast MRI as usually appropriate initial approaches.
Common pitfall: An assumed textbook appendix position can cause a localization error. Pregnancy changes initial options but does not establish an absolute prohibition against clinically necessary CT.
57.What distinguishes CT enterography from routine abdominal CT?
CT enterography combines ingested liquid to distend the small bowel with intravenous contrast to evaluate bowel-wall enhancement and surrounding tissues. A neutral or low-attenuation luminal background helps distinguish enhancing mucosa and wall from the contents; dense positive oral contrast may obscure this assessment. Distention separates opposing walls, while enhancement supports assessment of inflammatory or other abnormalities. Oral preparation and intravenous timing serve complementary mechanisms. Inadequate distention can limit interpretation despite a technically successful injection and acquisition.
Apply it
A patient needs evaluation of small-bowel inflammatory disease. Explain why the ordered liquid preparation matters: it distends bowel for wall assessment, while intravenous contrast supplies enhancement information that drinking liquid alone cannot provide.
Common pitfall: Strong IV enhancement does not compensate for collapsed bowel. Dense positive luminal opacification is not equivalent to neutral distention when assessing subtle mural enhancement.
ACR/RSNA RadiologyInfo: CT Enterography · ACR Manual on Contrast Media
58.Why does CT colonography require distention and possible follow-up colonoscopy?
CT colonography uses a prepared, gas-distended colon and CT images to assess the colonic lumen. Distention separates opposing walls and supports detection of protruding lesions; collapsed segments can limit evaluation. Computer-generated endoluminal views supplement cross-sectional review. The examination can detect a significant polyp but cannot remove it or obtain a tissue sample. A finding requiring treatment therefore leads to conventional colonoscopy, which performs a function CT colonography cannot provide.
Apply it
CT colonography identifies a significant polyp in an adequately distended segment. Explain that conventional colonoscopy is needed for removal or tissue sampling, even though CT has already supplied a detailed view of its location.
Common pitfall: A virtual endoluminal view is not a therapeutic endoscope. Poorly distended bowel also cannot be assumed normal simply because no convincing lesion is displayed.
59.How do excretory bladder imaging and retrograde cystography differ in injury assessment?
Delayed excretory imaging shows contrast entering the bladder after IV administration and renal filtration. Retrograde CT cystography actively fills and distends the bladder through a urinary catheter, creating the filling conditions needed to demonstrate leakage from an injured wall. Passive excretory filling, even with catheter clamping, cannot exclude bladder injury. For an adult with pelvic fracture and visible hematuria, EAU recommends cystography and specifies active retrograde filling with 300–350 mL of dilute contrast. Intraperitoneal leakage produces free contrast outlining bowel loops or abdominal viscera; extraperitoneal leakage typically appears as flame-shaped contrast in perivesical soft tissues. These volume and technique recommendations belong to the EAU guideline and this injury scenario, rather than every bladder examination.
Apply it
A stable adult has a pelvic fracture and gross hematuria, with some excreted contrast visible in the bladder on trauma CT. Explain why that finding does not replace active retrograde CT cystography. During review, distinguish contrast outlining bowel from contrast confined to tissues around the bladder.
Common pitfall: Visible bladder contrast does not establish adequate distention or exclude a wall defect. Do not generalize an adult injury filling volume to children or assume catheter placement is appropriate before possible urethral injury has been assessed.
EAU Guidelines on Urological Trauma - UROGENITAL TRAUMA GUIDELINES · ARRT Computed Tomography Examination Content Specifications · ACR/RSNA RadiologyInfo: Urography
60.How does CT guidance support biopsy and drainage?
CT guidance depicts a target and surrounding anatomy so a needle or catheter can be directed toward the intended location. Biopsy obtains tissue, whereas drainage removes material from a collection; these are different procedural goals despite sharing imaging guidance. Planning considers the target's location and intervening structures, while repeated localization confirms instrument position. Patient communication, monitoring and procedural confirmation complement image acquisition. Diagnostic CT identification of a lesion does not by itself complete an image-guided intervention.
Apply it
A CT-detected abdominal collection is scheduled for drainage. Identify the collection and intervening anatomy for procedural planning, and distinguish placement of a drainage catheter from obtaining a diagnostic tissue specimen through a biopsy procedure.
Common pitfall: Biopsy and drainage are not interchangeable just because both use a needle. A diagnostic scan shows anatomy, while intervention requires coordinated instrument localization and procedural care.
ACR/RSNA RadiologyInfo: Abdominal and Pelvic CT · ARRT Computed Tomography Examination Content Specifications
What to focus on during revision
The following are CertMedbry study suggestions. Use the official outline to check the full scope of your examination.
- Prioritize Procedures and Image Production while maintaining contrast-emergency and radiation-safety competence; the official scored allocations are 71, 52, 21 and 21.
- For each regional study, identify the target anatomy, contrast compartment, required enhancement phase, useful planes and a limitation that could invalidate the result.
- Recognize the third ventricle and thalami, orbital–ethmoid boundary, vertebral elements, carina, carotid bifurcation, ureteral course and cecal origin of the appendix, then connect those landmarks to image review.
- Practise CTDIvol, DLP, pitch, pixel-size, window-limit, SSDE, iodine-delivery, medication-volume and constrained noise calculations with units and explicit assumptions.
- Distinguish allergic-like reactions, physiologic reactions and extravasation using respiratory, circulatory and neurovascular cues, and explain the treatment mechanism that matches each pattern.
- Connect artifacts and image-quality problems to their physical causes before choosing reconstruction changes or considering another acquisition.
- Include the September 2026 additions, especially injection and scanning techniques, informatics, cardiac approaches, esophagram and urinary and colorectal protocols.
- Use the official outline to extend beyond these selected concepts, including additional anatomy, medications, radiation physics, personnel protection and every listed regional study.
A practical preparation plan
1. Map the full CT outline
Use the specifications effective September 1, 2026 as your coverage map. Mark each topic as explainable, partly understood or unfamiliar. Keep examination scope separate from education and clinical-experience eligibility documents.
2. Build regional protocol comparisons
Compare noncontrast head CT with perfusion, calcium scoring with coronary CTA, coronary CTA with TAVR planning, stone CT with urography, and enterography with colonography. For each pair, explain what anatomy, contrast route, timing and reconstruction change.
3. Work the physics in units
Calculate DLP, pitch, pixel size, window limits and injection quantities without referring to answer options. For noise and dose relationships, state what remains fixed and check whether automatic compensation changes the expected result.
4. Rehearse complication recognition
Use short cases to identify anaphylaxis, vasovagal patterns, unsafe access-device assumptions and extravasation escalation criteria. Explain the decisive finding, the matching treatment mechanism and the role of authorized response personnel.
5. Complete and explain the drills
Answer all 20 questions independently. For every item, explain the correct option and why each alternative is weaker. Record errors by mechanism, such as phase confusion, unit error or missing patient-specific criteria.
6. Recall, revisit and expand
Use the flashcards for spaced recall, including anatomic relationships, then revisit concepts you cannot explain without cues. Return to the official outline to study topics absent from this selective guide rather than treating completion of the drills as complete examination coverage.
Use your sample score as a starting point
The free set contains 20 original practice questions. It is a small learning sample, not an official examination or a validated pass prediction. Review each explanation and its source before moving to another topic.
Start the free sampleOfficial sources and updates
- ARRT Reference Documents by Discipline
- ARRT Computed Tomography Examination Content Specifications
- ARRT Computed Tomography (CT)
- ARRT Updated CT Documents
- ARRT Updates Passing Standard for the Computed Tomography Examination
- ACR Manual on Contrast Media landing page
- ACR Manual on Contrast Media
- CDC Clinical Safety: Hand Hygiene for Healthcare Workers
- NCI Radiation Risks and Pediatric Computed Tomography
- NCI Computed Tomography Scans and Cancer
- AAPM Report 96: The Measurement, Reporting, and Management of Radiation Dose in CT
- AAPM Report 220: Water Equivalent Diameter and Size-Specific Dose Estimates in CT
- AAPM CT Image Quality—A Summary
- Siemens Healthineers Academy: CT Basics
- Siemens Healthineers Academy: Advanced CT Concepts for Hybrid Imaging Technologists
- Siemens Healthineers Academy: CT Essentials—Reconstruction Parameters Part 2
- DICOM PS3.1: Referencing the DICOM Standard
- DICOM PS3.15: Attribute Confidentiality Profiles
- ACR/RSNA RadiologyInfo: Head CT
- ACR/RSNA RadiologyInfo: Hearing Loss and/or Vertigo
- ACR/RSNA RadiologyInfo: CT Scan of the Spine
- ACR/RSNA RadiologyInfo: CT Angiography
- ACR/RSNA RadiologyInfo: Coronary CTA
- ACR/RSNA RadiologyInfo: Chest CT
- ACR/RSNA RadiologyInfo: Urography
- ACR/RSNA RadiologyInfo: Acute Onset Flank Pain—Suspicion of Stone Disease
- ACR/RSNA RadiologyInfo: CT Colonography
- ACR/RSNA RadiologyInfo: CT Enterography
- ACR/RSNA RadiologyInfo: CT Perfusion Imaging of the Head
- ACR/RSNA RadiologyInfo: CT of the Sinuses
- ACR/RSNA RadiologyInfo: Myelography
- ACR/RSNA RadiologyInfo: Cardiac CT for Calcium Scoring
- ACR/RSNA RadiologyInfo: Abdominal and Pelvic CT
- postprimary-handbook.pdf
- About the Exam - ARRT
- Exam Duration and Length - ARRT
- RPT_96.pdf
- AAPM Reports - Size-Specific Dose Estimates (SSDE) in Pediatric and Adult Body CT Examinations
- Statement from Drugs and Contrast Media Committee on Supervision of Contrast Material Administration
- RPT_220.pdf
- Preview
- Preview
- 6.9 Attribute Confidentiality Profiles
- arrt-postprimary-handbook.pdf
- E.3 Basic Application Level Confidentiality Options
- Contrast-Reaction-Card-Adult.pdf
- E.3 Basic Application Level Confidentiality Options
- Direct Arthrography
- EAU Guidelines on Urological Trauma - UROGENITAL TRAUMA GUIDELINES
- Neuroanatomy Online: Lab 7 (ƒ6) - Auditory, Vestibular, Gustatory and Olfaction Systems - Midbrain and Diencephalon
- FESS-Elective-3_24.pdf
- Anatomy Tables - Back & Spinal Cord
- Anatomy Tables - Peritoneal Cavity & Intestines
- Clinical Cases - Nephrolithiasis
- Feedback
- TopicNarrativePdf
- TopicNarrativePdf
- scct_tavi_tavr_ecd_2019.pdf
- Contrast… | The American Association for Thoracic Surgery | AATS
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