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Practice Exam
Question 1. Which physical property of ultrasound determines its ability to resolve small structures? A) Frequency B) Amplitude C) Velocity D) Wavelength Answer: A Explanation: Higher frequency ultrasound has shorter wavelength, which improves axial and lateral resolution, allowing visualization of smaller structures. Question 2. The acoustic impedance of a tissue is calculated by which formula? A) Density × Speed of sound B) Density ÷ Speed of sound C) Speed of sound ÷ Density D) Density + Speed of sound Answer: A Explanation: Acoustic impedance (Z) = ρ × c, where ρ is tissue density and c is the speed of sound in that tissue. Question 3. When an ultrasound beam encounters a boundary between two tissues with different impedances, what phenomenon primarily creates the image? A) Refraction B) Scattering C) Reflection D) Diffraction Answer: C
Practice Exam
Explanation: The difference in acoustic impedance causes part of the wave to be reflected back to the transducer, forming the basis of B‑mode imaging. Question 4. In decibel (dB) notation, an increase of 6 dB corresponds approximately to: A) Doubling the intensity B) Halving the intensity C) Tenfold increase in intensity D) No change in intensity Answer: A Explanation: A 6 dB increase represents roughly a two‑fold increase in acoustic intensity (10 log₁₀(2) ≈ 3 dB per factor of √2, so 6 dB ≈ 2 ×). Question 5. Which transducer type is most commonly used for superficial vascular imaging of the carotid arteries? A) Curved array B) Phased array C) Linear array D) Endocavitary Answer: C Explanation: Linear array transducers provide a rectangular field of view with high resolution at shallow depths, ideal for carotid and extremity vessels. Question 6. The purpose of the matching layer in a piezoelectric transducer is to: A) Increase the transducer’s weight B) Reduce acoustic impedance mismatch with tissue C) Provide electrical shielding
Practice Exam
B) Depth‑dependent attenuation of the ultrasound beam C) Differences in patient body habitus D) Operator hand pressure on the probe Answer: B Explanation: TGC allows the user to increase gain selectively at deeper depths to counteract attenuation, producing a uniformly bright image. Question 10. Spatial resolution is most directly affected by: A) Dynamic range setting B) Transducer frequency C) Doppler angle D) Pulse repetition frequency (PRF) Answer: B Explanation: Higher transducer frequencies produce shorter wavelengths, which improve spatial (axial and lateral) resolution. Question 11. According to the Doppler shift equation, an increase in the angle between the ultrasound beam and the direction of flow will: A) Increase the measured Doppler shift B) Decrease the measured Doppler shift C) Have no effect on the shift D) Reverse the direction of the shift Answer: B Explanation: The Doppler shift is proportional to cos θ; as the angle approaches 90°, cos θ decreases, reducing the observed frequency shift.
Practice Exam
Question 12. Pulsed‑wave (PW) Doppler is limited by aliasing because: A) The PRF is too low to sample high velocities accurately B) The beam is too wide C) The transducer cannot emit continuous waves D) The gain is set too high Answer: A Explanation: PW Doppler uses a finite PRF; if the blood velocity exceeds the Nyquist limit (PRF/2), the frequency shift wraps around, causing aliasing. Question 13. Continuous‑wave (CW) Doppler can measure very high velocities without aliasing because: A) It uses a very low PRF B) It transmits and receives simultaneously on separate crystals C) It employs a high‑frequency probe D) It relies on color mapping rather than spectral analysis Answer: B Explanation: CW Doppler continuously transmits and receives, allowing unlimited sampling of high velocities, thus avoiding aliasing, though it loses range specificity. Question 14. Which artifact is most commonly seen in color flow Doppler when the transducer is placed too close to the vessel wall? A) Mirror image B) Flash artifact C) Shadowing D) Reverberation Answer: B
Practice Exam
D) Elastic lamina Answer: C Explanation: The intima is the innermost layer and consists mainly of a single layer of endothelial cells lining the lumen. Question 18. According to Poiseuille’s law, which factor has the greatest effect on blood flow through a vessel, assuming all other variables are constant? A) Blood viscosity B) Vessel length C) Vessel radius D) Pressure gradient Answer: C Explanation: Flow is proportional to the fourth power of the radius (r⁴); thus, small changes in radius dramatically affect flow. Question 19. In the Bernoulli principle, an increase in blood velocity results in: A) An increase in pressure B) A decrease in pressure C) No change in pressure D) An increase in both pressure and velocity Answer: B Explanation: Bernoulli’s equation states that when velocity increases, static pressure decreases, assuming incompressible, non‑viscous flow. Question 20. High‑resistance vascular beds, such as the internal carotid artery, typically demonstrate which spectral waveform pattern?
Practice Exam
A] Low systolic peaks with continuous diastolic flow B] High systolic peaks with minimal diastolic flow C] Flat waveform throughout the cardiac cycle D] Triphasic waveform with reversal in diastole Answer: B Explanation: High‑resistance vessels have a sharp systolic upstroke and a rapid drop to low or absent diastolic flow. Question 21. A parabolic flow profile is characteristic of: A) Turbulent flow B) Laminar flow in a straight, non‑branching vessel C) Flow through a stenotic segment D) Flow in a highly compliant vein Answer: B Explanation: In laminar flow within a uniform tube, velocity is highest at the center and decreases toward the walls, forming a parabolic shape. Question 22. Which of the following is the most reliable criterion for grading carotid artery stenosis on duplex ultrasound? A) Peak systolic velocity (PSV) alone B) End‑diastolic velocity (EDV) alone C) ICA/CCA PSV ratio combined with absolute PSV D) Color Doppler mosaic pattern only Answer: C Explanation: The combination of ICA/CCA PSV ratio and absolute PSV provides a more accurate assessment of stenosis severity than either measurement alone.
Practice Exam
D) High‑resistance downstream bed Answer: B Explanation: Vasospasm reduces diastolic flow, producing a high‑resistance, blunted waveform pattern. Question 26. The Ankle‑Brachial Index (ABI) is calculated by: A) Dividing brachial systolic pressure by ankle systolic pressure B) Dividing ankle systolic pressure by brachial systolic pressure C) Adding ankle and brachial pressures together D) Subtracting brachial from ankle pressure Answer: B Explanation: ABI = (ankle systolic pressure) / (brachial systolic pressure). Values <0.9 suggest peripheral arterial disease. Question 27. In segmental arterial pressure testing of the lower extremities, the “four‑cuff” method involves: A) Simultaneous measurement of brachial, radial, ankle, and toe pressures B) Cuffs placed on the thigh, calf, ankle, and toe C) Cuffs on the thigh, calf, dorsalis pedis, and posterior tibial arteries D) Cuffs on both arms and both legs Answer: B Explanation: The four‑cuff technique uses cuffs on the proximal thigh, distal thigh (or calf), ankle, and toe to obtain segmental pressures. Question 28. A post‑exercise ankle‑brachial index that drops from 0.95 at rest to 0.68 after treadmill testing suggests:
Practice Exam
A) Normal arterial function B) Mild arterial disease C) Moderate to severe peripheral arterial disease D) Venous insufficiency Answer: C Explanation: A post‑exercise ABI drop >0.15–0.20 indicates significant flow limitation due to arterial disease. Question 29. In pulse volume recording (PVR), a “triphasic” waveform indicates: A) Normal arterial compliance B) Severe arterial stenosis C) Venous reflux D) Arteriovenous fistula presence Answer: A Explanation: A triphasic waveform (sharp systolic upstroke, brief reversal, and diastolic forward flow) is typical of healthy peripheral arteries. Question 30. Which duplex finding is most characteristic of a true aneurysm of the femoral artery? A) Focal narrowing with high velocity jet B) Saccular outpouching with turbulent color flow and a “yin‑yang” pattern C) Uniformly increased PSV throughout the segment D) Absence of flow on color Doppler Answer: B Explanation: True aneurysms appear as saccular or fusiform dilatations with turbulent, swirling color flow often described as a yin‑yang pattern.
Practice Exam
Explanation: Acute DVT appears as a non‑compressible vein containing hypoechoic or mixed‑echogenic thrombus; the vein cannot be flattened with probe pressure. Question 34. Venous reflux is defined sonographically as a reverse flow lasting longer than: A) 0.5 seconds B) 1.0 seconds C) 1.5 seconds D) 2.0 seconds Answer: C Explanation: Reflux time > 0.5 seconds is often used for superficial veins, but for deep veins and standard guidelines, > 1.0–1.5 seconds is considered abnormal; many vascular labs use 1.0 second for superficial and 1.5 seconds for deep. Question 35. In evaluating a hemodialysis arteriovenous fistula (AVF), which duplex parameter indicates a functional outflow vein? A) Low arterial PSV (< 30 cm/s) B) High venous PSV (> 200 cm/s) with low resistance index C) Absence of color flow in the vein D) Reversal of flow direction in the artery Answer: B Explanation: A mature AVF shows high flow velocities in the outflow vein and a low resistance arterial waveform due to the low‑resistance circuit. Question 36. The most common cause of a false aneurysm (pseudoaneurysm) after a femoral arterial puncture is: A) Atherosclerotic plaque rupture B) Infection of the arterial wall
Practice Exam
C) Incomplete hemostasis leading to a contained hematoma D) Congenital arterial wall weakness Answer: C Explanation: A pseudoaneurysm forms when blood leaks through a puncture site but is confined by surrounding tissue, creating a pulsatile sac. Question 37. In abdominal aortic aneurysm (AAA) surveillance, an endoleak after endovascular repair is best identified by which duplex finding? A) Uniform low‑velocity flow throughout the graft B) High‑velocity jet within the aneurysm sac on color Doppler C) Absence of flow in the graft lumen D) Normal PSV in the proximal aorta only Answer: B Explanation: Endoleaks appear as focal areas of high‑velocity color flow within the aneurysm sac, indicating persistent perfusion despite graft placement. Question 38. The renal‑aortic ratio (RAR) used to diagnose renal artery stenosis is calculated by: A) Renal artery PSV ÷ Aortic PSV B) Aortic PSV ÷ Renal artery PSV C) Renal artery EDV ÷ Aortic EDV D) Renal artery acceleration time ÷ Aortic acceleration time Answer: A Explanation: RAR = (renal artery peak systolic velocity) / (abdominal aortic PSV). A ratio > 3. suggests ≥ 60 % stenosis.
Practice Exam
Answer: B Explanation: MALS causes extrinsic compression of the celiac artery; inspiratory diaphragmatic descent relieves the compression, reducing PSV. Question 42. In portal hypertension, duplex ultrasound typically shows: A) Decreased portal vein diameter and flow reversal B) Increased portal vein diameter (> 13 mm) with hepatofugal (away from liver) flow C) Normal portal vein velocity but increased hepatic artery flow D) Absence of flow in the portal vein Answer: B Explanation: Portal hypertension leads to portal vein dilation and often hepatofugal flow due to elevated upstream pressure. Question 43. A transjugular intrahepatic portosystemic shunt (TIPS) is evaluated by duplex ultrasound primarily to assess: A) Hepatic artery stenosis B) Patency of the shunt and flow direction through the portal vein C) Biliary duct dilation D) Gallbladder wall thickness Answer: B Explanation: Post‑TIPS surveillance focuses on shunt patency, flow velocity, and direction to ensure adequate decompression of portal pressure. Question 44. Budd‑Chiari syndrome on hepatic duplex is characterized by: A) Absence of hepatic vein flow or reversed flow B) Increased arterial flow in the hepatic artery
Practice Exam
C) Normal portal vein velocity D) Dilated bile ducts Answer: A Explanation: Budd‑Chiari results from hepatic venous outflow obstruction, producing absent or reversed hepatic vein flow on Doppler. Question 45. The “flip‑flop” artifact in color Doppler is most commonly seen when: A) The transducer is angled too steeply relative to the vessel B) The patient holds breath during acquisition C) The gain is set too low D) The color box includes a highly reflective surface such as bone Answer: D Explanation: The flip‑flop (or “color bleed”) artifact occurs when strong reflections from bone or calcification cause color to appear in adjacent tissue. Question 46. In a high‑resolution linear transducer, decreasing the focal depth will: A) Increase the field of view B) Decrease lateral resolution at deeper structures C) Reduce the near‑field resolution D) Increase frame rate Answer: B Explanation: A shallower focus improves resolution near the focal zone but degrades lateral resolution at deeper depths. Question 47. Which of the following adjustments will most effectively reduce aliasing in a PW Doppler spectrum?
Practice Exam
Explanation: After a high‑grade stenosis, distal flow slows, producing a dampened waveform with reduced peak and prolonged systolic component. Question 50. The optimal angle for accurate Doppler velocity measurement is: A) 0° B) 30° C) 45° D) 60° Answer: C Explanation: While 0° provides the most accurate measurement, in practice an angle ≤ 60° is acceptable; 45° is the commonly recommended compromise to balance accuracy and feasibility. Question 51. In a duplex study of the lower extremity, an ankle systolic pressure of 70 mmHg with a normal brachial pressure of 130 mmHg yields an ABI of: A) 0. B) 0. C) 0. D) 1. Answer: A Explanation: ABI = 70 / 130 ≈ 0.54, indicating moderate peripheral arterial disease. Question 52. Which of the following describes the “windkessel” effect in arterial hemodynamics? A) Constant flow throughout systole and diastole B) Elastic recoil of large arteries that maintains diastolic flow C) Turbulent flow at arterial bifurcations
Practice Exam
D) Pressure drop across a stenosis proportional to velocity Answer: B Explanation: The windkessel model describes how the elastic storage of energy during systole sustains flow during diastole. Question 53. In an upper‑extremity arterial duplex, a subclavian artery PSV of 250 cm/s with a normal distal axillary PSV of 80 cm/s suggests: A) Normal flow B) Subclavian artery stenosis C) Axillary artery occlusion D) Venous thrombosis Answer: B Explanation: Elevated PSV in the subclavian artery with normal downstream velocities indicates a proximal stenosis. Question 54. A “mirror image” artifact in vascular ultrasound most commonly occurs when imaging: A) Superficial veins B) Deep arterial branches adjacent to bone C) The carotid bifurcation near the jawline D) The liver near the diaphragm Answer: B Explanation: Strong reflectors such as bone can cause a duplicate image of a structure on the opposite side of the reflector, producing a mirror artifact. Question 55. During a transcranial Doppler study, a mean flow velocity (MFV) of 120 cm/s in the middle cerebral artery is considered:
