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Tomography CT Ultimate Exam
Question 1. Which of the following patient history items is most essential to screen for before administering iodinated contrast in a CT study? A) Hypertension B) Diabetes mellitus C) History of severe asthma D) Prior allergic reaction to iodinated contrast Answer: D Explanation: Prior allergic reactions to iodinated contrast are a strong predictor of future contrast reactions and must be identified before administration. Question 2. A patient scheduled for a contrast-enhanced CT of the abdomen has a serum creatinine of 2.8 mg/dL and an estimated GFR of 30 mL/min/1.73 m². The most appropriate action is to: A) Proceed with standard contrast dose B) Use a reduced-dose, low-osmolar contrast agent C) Cancel the study and request an MRI D) Administer a diuretic before contrast injection Answer: B Explanation: In patients with reduced renal function, a low-osmolar, reduced-dose contrast protocol minimizes the risk of contrast-induced nephropathy. Question 3. Which of the following statements best describes the difference between ionic and non-ionic iodinated contrast media? A) Ionic agents have lower viscosity than non-ionic agents. B) Non-ionic agents are hyperosmolar compared with blood. C) Ionic agents are more likely to cause severe adverse reactions. D) Non-ionic agents contain no iodine. Answer: C
Tomography CT Ultimate Exam
Explanation: Ionic contrast media have higher osmolality and are associated with a higher incidence of severe hypersensitivity reactions. Question 4. During a power injector contrast injection, the recommended maximum pressure limit for most CT injectors is: A) 150 psi B) 300 psi C) 500 psi D) 700 psi Answer: B Explanation: Most modern CT power injectors are rated for a maximum pressure of 300 psi to prevent catheter rupture and extravasation. Question 5. The first step in managing a moderate contrast reaction (e.g., urticaria, mild bronchospasm) is to: A) Immediately stop the contrast injection and administer epinephrine. B) Continue the injection and observe. C) Stop the injection, place the patient in a supine position, and give antihistamines. D) Perform cardiac resuscitation. Answer: C Explanation: For moderate reactions, the injection should be stopped, the patient positioned supine, and antihistamines (and possibly corticosteroids) administered. Question 6. Which of the following is a typical sign of extravasation of iodinated contrast during a CT scan? A) Sudden drop in blood pressure B) Swelling and erythema at the injection site C) Increased heart rate D) Development of a rash on the chest Answer: B
Tomography CT Ultimate Exam
Question 10. The CT Dose Index (CTDI) is measured in: A) Millisieverts (mSv) B) Milligrays (mGy) C) Gray (Gy) D) Sieverts (Sv) Answer: B Explanation: CTDI is expressed in milligrays (mGy) and represents the dose from a single axial scan. Question 11. Which of the following dose-reduction technologies uses adaptive modulation of the tube current based on patient size? A) Iterative reconstruction B) Smart mA (or CareDose) C) Dual-energy scanning D) High-pitch helical mode Answer: B Explanation: Smart mA or CareDose adjusts the tube current (mA) in real time according to patient attenuation, reducing dose while maintaining image quality. Question 12. In helical (spiral) CT scanning, the pitch is defined as: A) Table feed per rotation divided by detector width B) Tube voltage divided by tube current C) Slice thickness multiplied by reconstruction interval D) Number of detector rows activated per rotation Answer: A Explanation: Pitch = (table movement per rotation) / (total nominal detector width). It influences scan speed and dose.
Tomography CT Ultimate Exam
Question 13. Which reconstruction algorithm is most appropriate for evaluating lung parenchyma? A) Bone kernel B) Soft-tissue kernel C) Lung kernel (high-frequency) D) Edge-enhancement kernel Answer: C Explanation: A high-frequency lung kernel emphasizes fine detail and air-tissue interfaces, improving visualization of pulmonary structures. Question 14. Iterative reconstruction (IR) differs from filtered back-projection (FBP) primarily by: A) Using a higher kVp B) Reducing image noise through repeated modeling of the acquisition process C) Increasing the slice thickness automatically D) Eliminating the need for contrast agents Answer: B Explanation: IR algorithms iteratively compare the acquired data with a model of the imaging system, reducing noise and improving low-dose image quality. Question 15. Which post-processing technique best displays the vascular tree of the pulmonary arteries in a CTA? A) Maximum intensity projection (MIP) B) Minimum intensity projection (MinIP) C) Volume rendering (VR) with opacity mapping D) Surface shading Answer: A Explanation: MIP displays the highest attenuation voxels along each line of sight, highlighting contrast-filled vessels.
Tomography CT Ultimate Exam
Question 19. Which of the following is a contraindication to the use of oral barium sulfate contrast? A) Suspected small-bowel obstruction B) Known iodine allergy C) Pregnancy D) Chronic kidney disease Answer: A Explanation: Barium can exacerbate an obstruction or perforation; water-soluble contrast is preferred in such cases. Question 20. In CT imaging, the term “partial-volume averaging” refers to: A) Averaging multiple scans to reduce noise B) Blurring of small structures when a voxel contains more than one tissue type C) The effect of beam hardening in dense objects D) The use of overlapping slices to increase resolution Answer: B Explanation: Partial-volume averaging occurs when a voxel includes multiple tissue densities, resulting in an averaged attenuation value and loss of detail. Question 21. Which DICOM attribute is essential for ensuring proper patient identification across modalities? A) Study Instance UID B) Patient’s Name (0010,0010) C) Series Number (0020,0011) D) Image Position (Patient) (0020,0032) Answer: B Explanation: The Patient’s Name tag is a primary identifier used to match images to the correct individual.
Tomography CT Ultimate Exam
Question 22. A 65-year-old male with a known pacemaker requires a chest CT. Which precaution is most appropriate? A) Use a high-dose protocol to ensure image quality. B) Perform the scan without any radiation shielding. C) Verify that the pacemaker is MRI-compatible before proceeding. D) Document the device, use lowest reasonable dose, and monitor for device malfunction. Answer: D Explanation: Documenting the device and employing dose-reduction strategies while monitoring for any malfunction is standard practice for patients with implanted cardiac devices. Question 23. Which of the following is the most accurate description of the term “effective dose” in CT? A) The dose absorbed by the skin during a scan. B) The dose measured at the center of the phantom. C) A weighted sum of organ doses reflecting stochastic risk. D) The total amount of contrast media administered. Answer: C Explanation: Effective dose (measured in mSv) combines organ doses using tissue weighting factors to estimate overall cancer risk. Question 24. During a CT scan of the cervical spine, a patient experiences a sudden drop in oxygen saturation. The immediate action should be to: A) Continue the scan to finish the study. B) Administer a bolus of contrast immediately. C) Stop the scan, assess airway, and provide supplemental oxygen. D) Increase the tube current to improve image quality. Answer: C Explanation: Patient safety supersedes imaging; stopping the scan and addressing hypoxia is the correct response.
Tomography CT Ultimate Exam
Explanation: Although shellfish allergy does not directly predict iodinated contrast reaction, premedication with steroids and antihistamines is often employed for any prior severe contrast reaction. Question 28. Which of the following infection-control precautions is required when performing a CT-guided biopsy? A) Airborne precautions only B) Contact precautions for all patients C) Standard precautions plus sterile field preparation D) Droplet precautions only Answer: C Explanation: Standard precautions plus aseptic technique (sterile field) are essential for invasive procedures like CT-guided biopsies. Question 29. In CT image quality assessment, “uniformity” refers to: A) The consistency of noise across the image. B) The ability to differentiate two low-contrast objects. C) The constancy of CT numbers across a homogeneous phantom. D) The spatial resolution measured in line pairs per cm. Answer: C Explanation: Uniformity evaluates whether the CT number remains consistent across a uniform material, indicating proper scanner performance. Question 30. When scanning a pediatric patient, the most important principle to apply is: A) Use the highest possible kVp for better penetration. B) ALARA (As Low As Reasonably Achievable) to minimize radiation dose. C) Increase slice thickness to speed up acquisition. D) Avoid using any contrast agents. Answer: B
Tomography CT Ultimate Exam
Explanation: Pediatric imaging demands strict adherence to ALARA to limit radiation exposure while maintaining diagnostic quality. Question 31. Which of the following is a typical indication for a CT pulmonary angiography (CTPA)? A) Evaluation of mediastinal lymphadenopathy B) Assessment of pulmonary embolism C) Screening for lung cancer in smokers D) Measurement of diaphragmatic excursion Answer: B Explanation: CTPA is the gold-standard imaging test for detecting acute pulmonary embolism. Question 32. The term “bolus tracking” is most closely associated with which of the following parameters? A) Automatic exposure control B) Timing of scan initiation based on contrast arrival C) Real-time adjustment of pitch D) Patient positioning on the table Answer: B Explanation: Bolus tracking monitors contrast density in a region of interest and triggers the scan when a preset threshold is reached. Question 33. When performing a CT of the abdomen with oral water-soluble contrast, the typical volume administered is: A) 10–20 mL B) 50–100 mL C) 500–1000 mL over several hours D) 2000 mL in a single dose Answer: C
Tomography CT Ultimate Exam
Explanation: Ring artifacts arise from defective or miscalibrated detector elements producing concentric rings in the image. Question 37. In a CT angiography of the abdomen, the optimal timing for arterial phase imaging after contrast injection is approximately: A) 10–15 seconds B) 30–40 seconds C) 60–70 seconds D) 90–120 seconds Answer: B Explanation: The arterial phase typically peaks around 30–40 seconds post-injection, allowing optimal visualization of arterial structures. Question 38. The primary advantage of using a “low-kVp” protocol for contrast-enhanced CT of the abdomen is: A) Reduced patient motion artifacts. B) Increased iodine attenuation, improving contrast conspicuity. C) Decreased image noise without any dose penalty. D) Shorter scan time. Answer: B Explanation: Lower kVp increases the photoelectric effect, enhancing iodine attenuation and improving contrast resolution, though it may increase noise. Question 39. Which of the following is NOT a component of the CT gantry? A) X-ray tube B) Detector array C) Patient table D) Rotating collimator Answer: C Explanation: The patient table is separate from the gantry; the gantry houses the tube, detector, and collimator.
Tomography CT Ultimate Exam
Question 40. When performing a CT of the cervical spine, the most appropriate slice thickness for evaluating bony detail is: A) 5 mm B) 3 mm C) 1 mm D) 0.5 mm Answer: C Explanation: Thin slices (≈1 mm) provide high spatial resolution necessary for detailed assessment of cervical vertebrae. Question 41. In CT imaging, “noise” is best described as: A) Random variation in pixel values unrelated to true attenuation. B) The sharpness of edge transitions. C) The degree of beam hardening. D) The contrast between bone and soft tissue. Answer: A Explanation: Noise refers to stochastic fluctuations in measured signal that manifest as graininess in the image. Question 42. A patient with a known allergy to iodine is scheduled for a CT angiogram. The safest alternative imaging modality is: A) MRI with gadolinium contrast B) Ultrasound with Doppler C) Non-contrast CT D) Nuclear medicine perfusion scan Answer: A Explanation: MRI with gadolinium avoids iodinated contrast and can provide vascular imaging, though renal function must be considered.
Tomography CT Ultimate Exam
Question 46. During a CT scan, the technologist observes a sudden increase in the displayed dose-length product (DLP). The most likely explanation is: A) The patient moved out of the scan field. B) The scanner automatically increased mA due to higher attenuation. C) The contrast injector failed. D) The reconstruction algorithm changed. Answer: B Explanation: Automatic exposure control raises tube current when the system detects increased patient attenuation, resulting in higher DLP. Question 47. Which of the following is the best method to verify correct patient positioning before a CT head scan? A) Visual inspection of the laser crosshair only. B) Use of a scout (localizer) image to confirm the anatomy is centered. C) Relying on the technologist’s memory of prior scans. D) Positioning based on external landmarks alone. Answer: B Explanation: A scout image allows the technologist to ensure the region of interest is correctly centered and aligned before acquiring diagnostic images. Question 48. In CT of the thorax, the “lung window” typically uses a window width (WW) of about: A) 400–500 HU and level (WL) of –600 HU B) 1500–2000 HU and level of 0 HU C) 80–120 HU and level of 40 HU D) 200–300 HU and level of 100 HU Answer: A Explanation: Lung windows have a wide WW (400–500) to display the low-attenuation lung parenchyma, with a WL around – 600 HU.
Tomography CT Ultimate Exam
Question 49. Which of the following is a key advantage of dual-source CT scanners? A) Ability to acquire two simultaneous energy spectra for dual-energy imaging. B) Reduced need for contrast agents. C) Automatic patient positioning without technologist input. D) Lower radiation dose than single-source scanners in all protocols. Answer: A Explanation: Dual-source CT uses two independent X-ray tubes and detectors, enabling simultaneous acquisition of two energy spectra for dual-energy applications. Question 50. The most appropriate action when a patient’s blood glucose is >250 mg/dL before a contrast-enhanced CT of the abdomen is: A) Cancel the exam. B) Proceed without contrast. C) Administer insulin and recheck glucose before proceeding. D) Dilute the contrast with saline. Answer: C Explanation: High glucose can increase the risk of contrast-induced nephropathy; correcting hyperglycemia before contrast administration is recommended. Question 51. In a CT urography protocol, the “excretory phase” is typically obtained at what time after contrast injection? A) 5–10 seconds B) 30–45 seconds C) 70–90 seconds D) 10–15 minutes Answer: D Explanation: The excretory phase captures contrast excreted into the collecting system, usually 10–15 minutes post-injection.
Tomography CT Ultimate Exam
Question 55. In CT of the temporal bone, the optimal reconstruction kernel to evaluate fine bony structures is: A) Soft-tissue kernel B) Bone kernel (high-frequency) C) Lung kernel D) Standard kernel Answer: B Explanation: A high-frequency bone kernel enhances edge definition, critical for visualizing the intricate osseous anatomy of the temporal bone. Question 56. Which of the following is NOT a standard precaution for preventing contrast extravasation? A) Using a large-gauge (18- 20 G) IV catheter. B) Verifying catheter placement before injection. C) Injecting contrast at the highest possible pressure. D) Monitoring the injection site during administration. Answer: C Explanation: High injection pressures increase the risk of extravasation; pressures should stay within manufacturer-specified limits. Question 57. In CT imaging, the term “pitch factor” of 1.5 indicates that: A) The table moves 1.5 mm per rotation. B) The table moves 1.5 times the detector width per rotation. C) The tube voltage is increased by 50 %. D) The scan time is reduced by 50 %. Answer: B Explanation: Pitch = table travel per rotation / total detector width. A pitch of 1. means the table moves 1.5 × detector width each rotation.
Tomography CT Ultimate Exam
Question 58. Which of the following is the most appropriate method for reducing metal artifacts in a CT angiogram of the lower extremity with a metallic knee prosthesis? A) Increase kVp to 140 kVp B) Use a metal-artifact reduction (MAR) algorithm during reconstruction C) Decrease mAs to lower dose D) Apply a lung kernel Answer: B Explanation: MAR algorithms are specifically designed to correct beam-hardening and photon-starvation artifacts caused by metal implants. Question 59. The primary purpose of a “non-contrast” CT of the head in the setting of acute stroke is to: A) Detect early ischemic changes and exclude hemorrhage. B) Visualize the cerebral vasculature. C) Assess the blood-brain barrier integrity. D) Measure intracranial pressure directly. Answer: A Explanation: Non-contrast CT quickly identifies intracranial hemorrhage and early signs of ischemia, guiding acute stroke management. Question 60. Which of the following best describes “dose modulation” in CT? A) Changing the contrast concentration during the scan. B) Adjusting tube current (mA) in real time based on patient anatomy. C) Varying the slice thickness automatically. D) Switching between axial and helical acquisition modes. Answer: B Explanation: Dose modulation (e.g., automatic exposure control) varies mA according to patient size and attenuation to optimize dose.
