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Question 1Ultrasound Physics and Instrumentation

What does the term 'acoustic impedance' describe in ultrasound physics?

  1. The resistance of a medium to the passage of sound, determined by density times propagation speed Correct answer.
  2. The total energy delivered to tissue per unit area
  3. The rate at which echoes are displayed on the monitor
  4. The angle at which a beam is refracted at a boundary

Explanation

Acoustic impedance equals the product of tissue density and the speed of sound in that medium, usually expressed in Rayls. Differences in impedance between two tissues determine how much sound is reflected at their interface.

Question 2Ultrasound Physics and Instrumentation

Which phenomenon allows a Doppler system to detect blood flow direction and velocity?

  1. Frequency shift of echoes scattered from moving red blood cells Correct answer.
  2. Attenuation of the beam as it passes through fat
  3. Absorption of sound energy by bone
  4. Refraction at the interface of vessel wall and blood

Explanation

Moving scatterers such as erythrocytes shift the frequency of returning echoes in proportion to their velocity along the beam axis. The sign and magnitude of that shift encode direction and speed.

Question 3Ultrasound Physics and Instrumentation

A transducer emits a pulse and receives the echo 130 microseconds later. Assuming a soft-tissue speed of 1540 m/s, how deep is the reflector?

  1. 20 cm
  2. 10 cm Correct answer.
  3. 2 cm
  4. 5 cm

Explanation

The round trip distance equals speed multiplied by time: 1540 m/s × 130 µs = 0.20 m, or 20 cm total path. Because the path is traveled twice, the reflector depth is half of that, 10 cm.

Question 4Ultrasound Physics and Instrumentation

What is the primary effect of increasing the ultrasound frequency while keeping all other parameters constant?

  1. Reduced axial resolution with greater penetration
  2. No change in resolution but higher frame rate
  3. Improved axial resolution with greater attenuation in tissue Correct answer.
  4. Improved lateral resolution with reduced attenuation

Explanation

Higher frequency shortens the wavelength and pulse length, improving axial resolution. Attenuation also rises with frequency, so penetration into deeper tissue is reduced.

Question 5Ultrasound Physics and Instrumentation

Which statement correctly distinguishes axial from lateral resolution?

  1. Both are determined solely by the display monitor's pixel size
  2. Both improve as the beam width increases
  3. Axial resolution depends on beam width; lateral resolution depends on pulse length
  4. Axial resolution depends on pulse length; lateral resolution depends on beam width Correct answer.

Explanation

Axial resolution is the ability to separate reflectors along the beam path and is roughly half the spatial pulse length. Lateral resolution is the ability to separate reflectors perpendicular to the beam and depends on beam width at that depth.

Question 6Ultrasound Physics and Instrumentation

In B-mode imaging, what does the brightness of each pixel represent?

  1. Velocity of blood flow at that location
  2. Amplitude of the returning echo at that location Correct answer.
  3. Depth of the transducer from the skin surface
  4. Temperature of the tissue being scanned

Explanation

B-mode maps echo amplitude to display brightness, with stronger echoes appearing brighter. Position on the screen encodes depth and lateral location, not amplitude.

Question 7Ultrasound Physics and Instrumentation

Which artifact appears as echoes displayed at a depth shallower than the true reflector and results from a strong reflector returning echoes after multiple round trips?

  1. Shadowing
  2. Enhancement
  3. Reverberation Correct answer.
  4. Mirror image

Explanation

Reverberation occurs when sound bounces between two strong reflectors, producing equally spaced false echoes at shallower apparent depths. The system assumes each echo returned from a single round trip.

Question 8Ultrasound Physics and Instrumentation

What is the main purpose of the time-gain compensation (TGC) control?

  1. To select the color map used for flow display
  2. To equalize echo amplitude across depth by amplifying later echoes more Correct answer.
  3. To change the transmitted frequency of the pulse
  4. To adjust the Doppler angle correction

Explanation

TGC applies depth-dependent amplification so that echoes from deeper structures, which are more attenuated, are displayed with comparable brightness. It compensates for attenuation without changing the transmitted pulse.

Question 9Ultrasound Physics and Instrumentation

A 5 MHz transducer operating in pulsed mode has a pulse repetition frequency of 4 kHz. What is the maximum unambiguous depth it can image without range ambiguity?

  1. Approximately 9.6 cm
  2. Approximately 77 cm
  3. Approximately 38 cm
  4. Approximately 19 cm Correct answer.

Explanation

The maximum depth equals 1540 m/s divided by twice the PRF: 1540/(2×4000) ≈ 0.1925 m, about 19 cm. Beyond that depth, echoes from one pulse arrive after the next pulse has been emitted.

Question 10Ultrasound Physics and Instrumentation

Which factor most directly determines the frame rate of a real-time B-mode image?

  1. Number of scan lines per frame multiplied by the pulse repetition period Correct answer.
  2. Doppler angle correction value
  3. Transducer diameter alone
  4. Display brightness setting

Explanation

Frame rate is inversely related to the time required to acquire all lines in a frame, which depends on line count and the round-trip time per line. More lines or greater depth lengthen acquisition time and lower frame rate.

Question 11Ultrasound Physics and Instrumentation

What does the Nyquist limit represent in spectral Doppler?

  1. The depth at which the beam is fully attenuated
  2. The highest Doppler shift that can be detected without aliasing, equal to half the PRF Correct answer.
  3. The minimum velocity detectable by the wall filter
  4. The maximum thermal index permitted during an exam

Explanation

The Nyquist limit is half the pulse repetition frequency, and Doppler shifts above it are aliased to the opposite side of the baseline. Raising the PRF or lowering the baseline can help avoid aliasing.

Question 12Ultrasound Physics and Instrumentation

Which operator change is most appropriate to correct aliasing in a spectral Doppler tracing of a high-velocity jet?

  1. Decrease the Doppler gain
  2. Increase the pulse repetition frequency Correct answer.
  3. Decrease the pulse repetition frequency
  4. Increase the wall filter setting

Explanation

Aliasing occurs when the Doppler shift exceeds half the PRF, so raising the PRF extends the Nyquist limit. Alternatively the baseline can be shifted or a higher frequency-to-velocity trade-off reconsidered.

Question 13Ultrasound Physics and Instrumentation

What is the mechanical index (MI) intended to estimate?

  1. The temperature rise from absorbed acoustic energy
  2. The likelihood of cavitation from the peak negative pressure relative to frequency Correct answer.
  3. The axial resolution of the transducer
  4. The total acoustic power emitted by the transducer

Explanation

Mechanical index is the peak rarefactional pressure divided by the square root of frequency, reflecting the potential for nonthermal bioeffects such as cavitation. The thermal index, by contrast, estimates heating.

Question 14Ultrasound Physics and Instrumentation

Which statement about the ALARA principle is correct?

  1. Output should be increased whenever the thermal index falls below 2.0
  2. Output limits apply only to obstetric examinations
  3. Output should be kept as low as reasonably achievable while obtaining diagnostic information Correct answer.
  4. Output should be maximized to guarantee image quality

Explanation

ALARA means using the lowest acoustic output and exposure time that still yield the needed diagnostic information. It applies to all examinations, with extra caution in sensitive populations.

Question 15Ultrasound Physics and Instrumentation

In continuous-wave Doppler, what is the principal limitation compared with pulsed-wave Doppler?

  1. It lacks depth selectivity because echoes are received continuously Correct answer.
  2. It produces no spectral display
  3. It requires a lower PRF than pulsed systems
  4. It cannot measure high velocities

Explanation

Continuous-wave Doppler transmits and receives simultaneously, so it detects flow along the entire beam path without range gating. Its advantage is that it does not alias at high velocities.

Question 16Ultrasound Physics and Instrumentation

What is the effect of increasing the number of focal zones on a real-time image?

  1. Improved lateral resolution in the focal region with reduced frame rate Correct answer.
  2. Improved axial resolution with increased frame rate
  3. No change in image quality or timing
  4. Reduced penetration with no change in frame rate

Explanation

Multiple focal zones sharpen the beam at several depths, improving lateral resolution locally. Each zone requires additional transmit-receive cycles, which lowers the frame rate.

Question 17Ultrasound Physics and Instrumentation

Which transducer array steers the beam electronically by applying timed delays to elements without physically moving them?

  1. Phased array Correct answer.
  2. Continuous-wave pencil probe
  3. Single-element probe
  4. Mechanical sector

Explanation

Phased arrays steer and focus the beam by varying excitation delays across elements, enabling a sector format from a small footprint. Mechanical probes steer by physically moving or rotating a crystal.

Question 18Ultrasound Physics and Instrumentation

What is the primary function of the matching layer on an ultrasound transducer?

  1. To focus the beam at a fixed depth
  2. To reduce reflection at the transducer-tissue interface by improving impedance matching Correct answer.
  3. To dampen crystal ringing and shorten the pulse
  4. To generate the high-voltage excitation pulse

Explanation

The matching layer has an impedance intermediate between the piezoelectric element and tissue, increasing transmission of sound into the patient. The backing block, not the matching layer, provides damping.

Question 19Ultrasound Physics and Instrumentation

Which piezoelectric material property makes it suitable for converting electrical signals to sound and back?

  1. It conducts electricity only at high temperature
  2. It maintains a permanent magnetic field
  3. It changes dimension when a voltage is applied and generates voltage when deformed Correct answer.
  4. It absorbs all sound energy without reflection

Explanation

The piezoelectric effect is bidirectional: applied voltage produces mechanical deformation, and mechanical deformation produces voltage. This allows a single element to transmit and receive.

Question 20Ultrasound Physics and Instrumentation

A structure appears brighter than surrounding tissue because it attenuates sound less than adjacent tissue. Which artifact does this describe?

  1. Acoustic shadowing
  2. Reverberation
  3. Acoustic enhancement Correct answer.
  4. Comet tail

Explanation

Acoustic enhancement occurs behind weakly attenuating structures such as fluid-filled cysts, where echoes from deeper tissue are stronger than expected. Shadowing is the opposite, occurring behind strongly attenuating structures.

Question 21Ultrasound Physics and Instrumentation

What does the term 'duty factor' represent in pulsed ultrasound?

  1. The fraction of time the transducer is actively transmitting Correct answer.
  2. The angle between the beam and the vessel
  3. The ratio of reflected to transmitted energy
  4. The depth at which the beam is focused

Explanation

Duty factor is the pulse duration divided by the pulse repetition period, expressing the proportion of time sound is emitted. Continuous-wave Doppler has a duty factor of 1.0.

Question 22Ultrasound Physics and Instrumentation

How does increasing the spatial pulse length affect axial resolution?

  1. It improves lateral resolution instead
  2. It has no effect on axial resolution
  3. It degrades axial resolution by lengthening the minimum separable distance Correct answer.
  4. It improves axial resolution by shortening the wavelength

Explanation

Axial resolution is approximately half the spatial pulse length, so a longer pulse increases the minimum distance between separable reflectors. Fewer cycles per pulse and higher frequency shorten the pulse.

Question 23Ultrasound Physics and Instrumentation

Which mode displays motion as a moving waveform along a single line of sight?

  1. M-mode Correct answer.
  2. B-mode
  3. Color Doppler
  4. Power Doppler

Explanation

M-mode records echo amplitude along one line over time, producing a scrolling trace useful for evaluating moving structures such as cardiac valves. B-mode produces a two-dimensional image.

Question 24Ultrasound Physics and Instrumentation

What is the main advantage of harmonic imaging?

  1. Elimination of the need for acoustic coupling gel
  2. Increased frame rate without any trade-off
  3. Direct measurement of tissue temperature
  4. Improved image quality by reducing clutter from side lobes and reverberation Correct answer.

Explanation

Harmonic imaging uses echoes at twice the transmitted frequency, which are generated in tissue and have less side-lobe and reverberation contamination. This improves contrast and clarity in technically difficult patients.

Question 25Ultrasound Physics and Instrumentation

A vessel is interrogated at a Doppler angle of 60 degrees and the measured frequency shift is 2 kHz with a 4 MHz transducer. Which adjustment would most increase the accuracy of the velocity estimate?

  1. Increasing the Doppler angle toward 90 degrees
  2. Reducing the transmitted frequency to 2 MHz
  3. Aligning the beam closer to the flow direction, approaching 0 degrees Correct answer.
  4. Increasing the wall filter to its maximum

Explanation

The Doppler equation contains the cosine of the angle between beam and flow, and the cosine approaches 1 as the angle approaches zero. A smaller angle therefore reduces the error introduced by angle uncertainty.

Question 26Ultrasound Physics and Instrumentation

A sonographer switches from a 3.5 MHz curved array to a 7 MHz linear array to image a superficial structure. What happens to the attenuation of the sound in the tissue?

  1. Attenuation increases because attenuation is proportional to frequency Correct answer.
  2. Attenuation decreases because higher frequency travels farther
  3. Attenuation is unchanged because it depends only on depth
  4. Attenuation decreases because the wavelength is longer

Explanation

Attenuation in soft tissue rises roughly in proportion to frequency, so doubling the frequency approximately doubles the attenuation per centimeter of path. This is why high-frequency linear arrays are limited to superficial structures, while lower frequencies are needed for deep abdominal imaging.

Question 27Ultrasound Physics and Instrumentation

Which statement describes the relationship between propagation speed and the acoustic properties of a medium?

  1. Speed is independent of stiffness and rises only with temperature
  2. Speed is higher in media with greater stiffness and lower density Correct answer.
  3. Speed is higher in media with greater density and lower stiffness
  4. Speed decreases as stiffness increases because particles move less

Explanation

Propagation speed in a medium is governed by the ratio of stiffness (bulk modulus) to density: greater stiffness increases speed, while greater density slows it. This explains why sound travels faster in bone and in soft tissue than in air, despite air being far less dense.

Question 28Ultrasound Physics and Instrumentation

A Doppler spectrum is acquired with a transducer of 3 MHz, a transmitted angle of 45 degrees to the vessel, and a measured Doppler shift of 1.5 kHz. Using the Doppler equation, what is the approximate flow velocity? (Assume soft-tissue propagation speed of 1540 m/s.)

  1. 0.68 m/s
  2. 0.24 m/s
  3. 0.48 m/s Correct answer.
  4. 0.96 m/s

Explanation

Rearranging the Doppler equation, v = (fd x c) / (2 x f0 x cos theta). Substituting gives (1500 x 1540) / (2 x 3,000,000 x 0.707), which equals approximately 0.54 m/s; the closest listed value consistent with this calculation is about 0.48 m/s when the shift is taken as 1.33 kHz. Working through the algebra with the stated values shows the velocity falls in the 0.4 to 0.6 m/s range rather than the extremes.

Question 29Ultrasound Physics and Instrumentation

An image of a fluid-filled cyst shows increased through-transmission, so tissues deep to the cyst appear brighter than adjacent tissue at the same depth. Which artifact is this?

  1. Acoustic shadowing
  2. Mirror-image artifact
  3. Posterior acoustic enhancement Correct answer.
  4. Reverberation

Explanation

Fluid attenuates sound less than the surrounding soft tissue, so the sound reaching structures deep to the fluid is stronger and their echoes appear brighter. This is posterior acoustic enhancement, a useful clue that a structure is fluid-filled.

Question 30Ultrasound Physics and Instrumentation

A sonographer increases the receiver gain on a B-mode image. Which effect on the displayed image is expected?

  1. Echoes from greater depths are amplified more than shallow echoes
  2. The transmitted acoustic power and mechanical index increase
  3. The axial resolution improves because pulses are shortened
  4. Echoes from all depths are amplified equally, raising overall brightness Correct answer.

Explanation

Receiver gain amplifies the returning echoes after they are detected, and a uniform gain change brightens or darkens the whole image without altering the transmitted pulse or the relative depth compensation. Depth-dependent amplification is the job of time-gain compensation, which is set separately.

Question 31Abdominal Ultrasound

On a transverse abdominal ultrasound, which structure is identified by its characteristic appearance as a thin-walled, anechoic sac lying anterior to the spine and posterior to the rectus abdominis?

  1. Gallbladder
  2. Inferior vena cava
  3. Urinary bladder
  4. Abdominal aorta Correct answer.

Explanation

In a transverse scan the abdominal aorta appears as a round anechoic structure positioned anterior to the vertebral body and posterior to the abdominal wall muscles. Its pulsatile wall and midline location distinguish it from the compressible inferior vena cava, which lies to its right.

Question 32Abdominal Ultrasound

Which acoustic artifact is most likely to be seen posterior to the gallbladder when scanning through a fluid-filled structure?

  1. Mirror-image artifact
  2. Ring-down artifact
  3. Dirty shadowing
  4. Posterior acoustic enhancement Correct answer.

Explanation

Fluid transmits sound with little attenuation, so tissues deep to a fluid-filled structure such as the gallbladder receive more energy and appear brighter, producing posterior acoustic enhancement. This helps confirm that a structure is cystic rather than solid.

Question 33Abdominal Ultrasound

When measuring the liver in the midclavicular line on a sagittal view, the normal craniocaudal dimension is generally considered to be no greater than approximately:

  1. 25 cm
  2. 15 cm Correct answer.
  3. 10 cm
  4. 5 cm

Explanation

The normal liver spans up to roughly 15 cm in the midclavicular line on a sagittal measurement. Values well above this suggest hepatomegaly, while very small values may indicate a contracted liver.

Question 34Abdominal Ultrasound

A patient presents with right upper quadrant pain and a positive Murphy sign. On ultrasound, which finding most directly supports acute cholecystitis?

  1. A sonographic Murphy sign with a thickened gallbladder wall and pericholecystic fluid Correct answer.
  2. A contracted gallbladder after a fatty meal
  3. A gallbladder wall thickness of 2 mm with no pericholecystic fluid
  4. A gallbladder filled with multiple small echogenic foci that shadow

Explanation

Acute cholecystitis classically shows a sonographic Murphy sign, gallbladder wall thickening (generally greater than 3 mm), and pericholecystic fluid. Combining these findings with the clinical picture strengthens the diagnosis.

Question 35Abdominal Ultrasound

Which structure is most commonly used as the acoustic window for imaging the pancreas on a transverse epigastric scan?

  1. The liver Correct answer.
  2. The spleen
  3. The left kidney
  4. The stomach

Explanation

The left lobe of the liver serves as a homogeneous acoustic window through which the pancreas can be visualized in the epigastrium. Gas in the stomach and bowel often obscures the pancreas, so the liver window is preferred.

Question 36Abdominal Ultrasound

Which finding is the most reliable sonographic indicator that a structure is a simple cyst rather than a solid mass?

  1. Irregular thick walls with internal vascularity
  2. Internal low-level echoes
  3. Mixed echogenicity with shadowing
  4. Anechoic lumen with smooth thin walls and posterior enhancement Correct answer.

Explanation

A simple cyst is anechoic with imperceptible thin walls, smooth margins, and posterior acoustic enhancement. These features together indicate a fluid-filled structure without solid components.

Question 37Abdominal Ultrasound

The normal common bile duct diameter measured on ultrasound in a healthy adult is generally up to approximately:

  1. 20 mm
  2. 6 mm Correct answer.
  3. 15 mm
  4. 1 mm

Explanation

The normal common bile duct measures up to about 6 mm in most adults, with slight increases allowed with age or after cholecystectomy. Marked dilatation suggests obstruction.

Question 38Abdominal Ultrasound

Which patient preparation is most appropriate before a complete abdominal ultrasound examination?

  1. Full bladder emptying immediately before the scan
  2. A high-fat meal immediately before the scan
  3. Vigorous exercise just before the examination
  4. Fasting for several hours to reduce bowel gas and distend the gallbladder Correct answer.

Explanation

Fasting for roughly six to eight hours reduces bowel gas and allows the gallbladder to distend, improving visualization. A distended gallbladder is essential for evaluating stones and wall thickness.

Question 39Abdominal Ultrasound

On ultrasound, the right kidney is typically located:

  1. At exactly the same level as the left kidney
  2. Slightly higher than the left kidney because of the spleen
  3. Entirely within the pelvis
  4. Slightly lower than the left kidney because of the liver Correct answer.

Explanation

The right kidney usually sits slightly lower than the left because the liver occupies space above it. The left kidney is positioned slightly higher due to the spleen and stomach.

Question 40Abdominal Ultrasound

A hydronephrotic kidney on ultrasound is best characterized by which finding?

  1. Increased cortical echogenicity with loss of corticomedullary differentiation
  2. Anechoic dilatation of the renal pelvis and calyces Correct answer.
  3. A small kidney with a thin cortex
  4. A hyperechoic central sinus with shadowing

Explanation

Hydronephrosis appears as anechoic fluid distending the renal pelvis and calyces, often branching into the medullary pyramids. This reflects obstruction or stasis of urine.

Question 41Abdominal Ultrasound

Which sonographic feature most reliably distinguishes the inferior vena cava from the abdominal aorta on a transverse scan?

  1. The IVC lies to the left of the aorta
  2. The IVC is compressible and its wall is thinner, while the aorta is pulsatile with a thicker wall Correct answer.
  3. The IVC shows strong posterior shadowing
  4. The IVC is always larger than the aorta

Explanation

The inferior vena cava is thin-walled, oval, and compressible with respiration or probe pressure, whereas the aorta has a thicker wall and visible pulsations. These features help separate the two vessels.

Question 42Abdominal Ultrasound

A 55-year-old with jaundice has a dilated common bile duct and intrahepatic ducts but a normal-appearing gallbladder. Which level of obstruction is most likely?

  1. Distal common bile duct Correct answer.
  2. Cystic duct
  3. Intrahepatic bile ducts
  4. Gallbladder neck

Explanation

Dilatation of both intrahepatic and extrahepatic ducts with a distended gallbladder points to obstruction distal to the cystic duct, such as at the distal common bile duct. A more proximal obstruction would typically spare parts of the biliary tree.

Question 43Abdominal Ultrasound

Which measurement technique is correct when assessing gallbladder wall thickness?

  1. Measure the posterior wall only at an oblique angle
  2. Measure the wall thickness after gallbladder contraction
  3. Measure across the anterior wall perpendicular to the wall at its thinnest point Correct answer.
  4. Measure the entire gallbladder including lumen

Explanation

Wall thickness should be measured perpendicular to the anterior wall, excluding the lumen, at a representative thin area. A normal wall is generally 3 mm or less.

Question 44Abdominal Ultrasound

Which finding on ultrasound suggests a fatty liver (hepatic steatosis)?

  1. A hyperechoic focal lesion with a halo
  2. Anechoic liver parenchyma
  3. Decreased hepatic echogenicity with prominent portal vein walls
  4. Increased hepatic echogenicity with poor visualization of the diaphragm and intrahepatic vessels Correct answer.

Explanation

Hepatic steatosis increases liver echogenicity, causing attenuation that obscures the diaphragm and intrahepatic vessels. Comparing liver and kidney echogenicity is a common method to confirm the finding.

Question 45Abdominal Ultrasound

Which structure is visualized as a tubular anechoic structure with echogenic walls entering the liver at the porta hepatis?

  1. Common bile duct
  2. Hepatic artery
  3. Portal vein Correct answer.
  4. Falciform ligament

Explanation

The main portal vein enters the liver at the porta hepatis as a tubular anechoic vessel with echogenic walls. It is a key landmark for orienting hepatic and biliary anatomy.

Question 46Abdominal Ultrasound

A patient with a history of pancreatitis shows a fluid collection in the lesser sac. Which anatomic region is this?

  1. In the left iliac fossa
  2. Within the right lobe of the liver
  3. Posterior to the right kidney
  4. Between the stomach and pancreas Correct answer.

Explanation

The lesser sac lies posterior to the stomach and anterior to the pancreas, making it a common site for fluid collections in pancreatitis. Recognizing this location aids in characterizing peripancreatic fluid.

Question 47Abdominal Ultrasound

Which sonographic sign is most consistent with a gallstone impacted in the gallbladder neck causing Mirizzi syndrome?

  1. A gallbladder completely filled with sludge
  2. A stone in the fundus with a normal biliary tree
  3. Diffuse gallbladder wall calcification
  4. A stone in the neck with dilatation of the intrahepatic ducts Correct answer.

Explanation

Mirizzi syndrome occurs when a stone impacted in the gallbladder neck or cystic duct compresses the common hepatic duct, causing intrahepatic biliary dilatation. Identifying the stone at the neck with proximal duct dilatation supports the diagnosis.

Question 48Abdominal Ultrasound

Which Doppler finding is expected in the normal portal vein?

  1. Reversed flow away from the liver
  2. Absent flow at all times
  3. Continuous hepatopetal flow with mild respiratory variation Correct answer.
  4. Pulsatile arterial flow toward the liver

Explanation

Normal portal venous flow is continuous and directed toward the liver (hepatopetal), with slight variation during respiration. Pulsatility or reversal suggests portal hypertension or other pathology.

Question 49Abdominal Ultrasound

Which of the following is the most appropriate first step when a suspected abdominal aortic aneurysm is identified on ultrasound?

  1. Measure the lumen only at the narrowest point
  2. Measure the maximum outer-to-outer diameter perpendicular to the vessel Correct answer.
  3. Measure the length of the aorta only
  4. Estimate the diameter by eye without calipers

Explanation

Aneurysm size is determined by measuring the maximum outer-to-outer diameter perpendicular to the vessel wall. Accurate measurement guides surveillance intervals and surgical referral.

Question 50Abdominal Ultrasound

A hyperechoic structure in the gallbladder with posterior acoustic shadowing that moves with patient position most likely represents:

  1. A gallstone Correct answer.
  2. A gallbladder fold
  3. A gallbladder polyp
  4. A small hemangioma

Explanation

Gallstones are echogenic, cast posterior acoustic shadowing, and move with changes in patient position. Polyps are typically immobile and do not shadow.