Which outcome would be present if the sample volume gate is larger than the examined vessel?
Correct Answer: C
When the sample volume (gate) is too large, it captures signals from both the vessel and surrounding tissues or adjacent flows. This leads to a broadening of the spectral waveform and produces "spectral noise" or "spectral broadening," reducing the accuracy of velocity measurements and waveform analysis. Aliasing results from high velocity relative to the Nyquist limit, not from gate size. According to Zwiebel's Introduction to Vascular Ultrasound: "Increasing the sample volume beyond the vessel size causes spectral broadening, resulting in spectral noise and inaccurate Doppler measurements." Reference: Zwiebel WJ, Pellerito JS. Introduction to Vascular Ultrasound. 6th ed. Elsevier, 2019. AIUM Practice Parameter for Spectral Doppler Ultrasound, 2021. -
Question 52
Which characteristic is associated with complex pleural effusion?
Correct Answer: D
A complex pleural effusion often contains internal septations or fibrin strands, distinguishing it from simple anechoic effusion. These septations suggest exudative processes such as infection, malignancy, or hemothorax. According to Rumack's Diagnostic Ultrasound: "Complex pleural effusions demonstrate internal septations or loculations, often related to infection or malignancy." Reference: Rumack CM, Wilson SR, Charboneau JW, Levine D. Diagnostic Ultrasound. 5th ed. Elsevier, 2017. AIUM Practice Parameter for Thoracic Ultrasound, 2020. -
Question 53
What is the location of the left lobe of the thyroid gland?
Correct Answer: C
The left lobe of the thyroid is located anterolateral to the esophagus. On transverse ultrasound imaging, the esophagus can often be seen posterior to the left thyroid lobe as a circular structure with echogenic mucosa and hypoechoic muscular layer. The longus colli muscle lies posterior to the thyroid. The thyroid is anterior to the trachea but this refers more to the isthmus or midline portion. According to Rumack's Diagnostic Ultrasound: "The esophagus is seen as a target-shaped structure posterior to the left thyroid lobe; thus, the thyroid lobe is anterolateral to the esophagus." Reference: Rumack CM, Wilson SR, Charboneau JW, Levine D. Diagnostic Ultrasound. 5th ed. Elsevier, 2017. AIUM Practice Parameter for Thyroid Ultrasound, 2020. -
Question 54
Which clinical finding is most likely associated with the pathology in this image?
Correct Answer: A
The ultrasound image shows a classic longitudinal view of a markedly thickened pyloric muscle with an elongated pyloric channel. This finding is consistent with hypertrophic pyloric stenosis (HPS), a condition most commonly seen in male infants between 2 and 8 weeks of age. The most characteristic clinical finding associated with HPS is an "olive-shaped" palpable mass in the right upper quadrant or epigastric region, which represents the hypertrophied pylorus. Clinical presentation of HPS includes: * Non-bilious projectile vomiting (due to gastric outlet obstruction) * Dehydration and weight loss * A palpable "olive" mass on physical exam * Visible peristalsis may be noted on the abdominal wall Sonographic diagnostic criteria for HPS: * Pyloric muscle thickness # 3 mm * Pyloric channel length # 15-17 mm * "Cervix sign" or "target sign" (transverse view) * Failure of gastric contents to pass through the pylorus on real-time imaging Differentiation from other options: * B. Fever of unknown origin: Not characteristic of HPS. * C. Red currant jelly stools: Classic for intussusception. * D. Bilious vomiting: Seen in distal duodenal or jejunal obstruction, not in pyloric stenosis (vomiting is non-bilious in HPS). References: Rumack CM, Wilson SR, Charboneau JW, Levine D. Diagnostic Ultrasound. 5th Edition. Elsevier, 2018. Chapter: Gastrointestinal Tract, pp. 474-479. American College of Radiology (ACR). Appropriateness Criteria - Vomiting in Infants Up to 3 Months of Age. Radiopaedia.org. Hypertrophic pyloric stenosis:https://radiopaedia.org/articles/hypertrophic-pyloric-stenosis
Question 55
Which artifact is seen within the gallbladder in this image?
Correct Answer: D
The ultrasound image demonstrates multiple parallel echogenic lines within the gallbladder lumen, extending distally and diminishing in intensity. These equidistant lines are classic for a reverberation artifact. Reverberation occurs when the ultrasound beam reflects multiple times between two strong reflectors (such as the anterior gallbladder wall and the transducer), creating repeating echoes that appear as equally spaced lines. This is frequently seen in: * The gallbladder (especially when collapsed or near the wall) * Near air-filled structures * With metallic objects or surgical clips Reverberation does not represent a true anatomical structure and should be distinguished from real pathology. Comparison of answer choices: * A. Banding refers to speed displacement or slice-thickness artifacts and typically does not appear as repetitive lines. * B. Shadowing is a dark band posterior to highly attenuating structures like gallstones or bone, not present here. * C. Attenuation is a general term for the reduction in sound energy as it travels-posterior acoustic shadowing is one type. * D. Reverberation - Correct. The characteristic bright, parallel lines within the gallbladder lumen confirm this artifact. References: Kremkau FW. Sonography Principles and Instruments, 9th ed. Elsevier; 2015. Rumack CM, Wilson SR, Charboneau JW, Levine D. Diagnostic Ultrasound, 5th ed. Elsevier; 2017. Hagen-Ansert SL. Textbook of Diagnostic Sonography, 8th ed. Elsevier; 2017.
