Ultrasound — MCQs

Ultrasound Indian Medical PG Practice Questions and MCQs

Question 191: Acoustic shadow is produced by the following except

A. Calculus
B. Bone
C. Gas
D. Fat (Correct Answer)

Explanation: ***Fat*** - Fat has a **low acoustic impedance** and typically allows ultrasound waves to pass through with minimal reflection, thus it does not produce an **acoustic shadow**. - Instead of shadowing, fat often appears **hyperechoic** or **isoechoic** to surrounding tissues with good sound transmission. *Calculus* - **Calculi** (e.g., gallstones, kidney stones) are extremely dense and highly reflective, causing almost all ultrasound waves to be **absorbed or reflected**. - This leads to a distinct **anechoic area** (shadow) behind the calculus, as no sound waves penetrate beyond it. *Bone* - **Bone** is a hard, dense structure with high acoustic impedance, causing significant **reflection and attenuation** of ultrasound waves. - This blockage of sound waves results in a prominent **acoustic shadow** posterior to the bone, making structures behind it difficult to visualize. *Gas* - **Gas** (e.g., in bowel loops) has a very low acoustic impedance compared to soft tissue, creating a large **impedance mismatch** that leads to almost complete **reflection of ultrasound waves**. - The rapid scattering and reflection of sound waves by gas create a "dirty" or **"reverberation" shadow**, characterized by multiple bright echoes and lack of posterior visualization.

Question 192: The recommended Doppler angle for accurate velocity measurement in Doppler ultrasound is

A. 45-60 degrees (Correct Answer)
B. 60-80 degrees
C. 90 degrees
D. 80-110 degrees

Explanation: ***45-60 degrees*** - This range provides the best **practical compromise** between maximizing the Doppler shift signal and minimizing angle-related errors in clinical practice. - Within this angle, a significant component of the blood flow is detected, allowing for accurate **velocity measurements** while maintaining good acoustic access. - While 0 degrees is theoretically optimal (maximum Doppler shift), **45-60 degrees** represents the **clinically recommended range** that balances signal strength with practical probe positioning. *60-80 degrees* - While occasionally acceptable, angles above 60 degrees lead to a more significant decrease in the **Doppler shift magnitude**, making measurements more sensitive to small angling errors. - This range can lead to underestimation of **blood flow velocity** due to the cosine function approaching zero at higher angles, with **errors exceeding 50%** beyond 60 degrees. *90 degrees* - At 90 degrees, the cosine of the angle is zero, meaning there is theoretically **no Doppler shift** detected. - This angle results in complete loss of the **Doppler signal**, making it impossible to measure blood flow velocity. *80-110 degrees* - This range includes angles close to or beyond 90 degrees, where the **Doppler signal** becomes extremely weak or non-existent, leading to highly inaccurate or impossible velocity measurements. - Such angles should be strictly avoided in **Doppler ultrasound** for quantitative velocity analysis.

Question 193: Which of the following is false with regards to ultrasonography?

A. Interpretation only possible during the examination
B. Inexpensive
C. No radiation
D. Not good for soft tissue (Correct Answer)

Explanation: ***Not good for soft tissue*** - This statement is **false** because ultrasonography is exceptionally good for imaging **soft tissues**, such as muscles, tendons, ligaments, and organs, providing detailed real-time visualization. - It excels in differentiating between solid and cystic structures and assessing blood flow within soft tissues. *Interpretation only possible during the examination* - This statement is **true** for many basic ultrasound examinations, where the dynamic nature of the scan often requires the sonographer or radiologist to interpret findings in **real-time**. - While images can be saved, the ability to manipulate the probe and observe structures in motion during the scan is crucial for a comprehensive diagnosis. *Inexpensive* - This statement is generally **true** when compared to other advanced imaging modalities like MRI or CT scans, making it a more **cost-effective** option for many diagnostic purposes. - The equipment and operational costs of ultrasound are lower, contributing to its affordability. *No radiation* - This statement is **true** as ultrasonography uses **sound waves** (high-frequency mechanical waves) rather than ionizing radiation, making it a safe imaging modality, especially for pregnant women and children. - The absence of radiation exposure is a significant advantage, allowing for repeated examinations without cumulative risk.

Question 194: Which of the following is the best in-vivo screening choice for carotid artery stenosis?

A. Digital Subtraction Angiography (DSA)
B. CT
C. MRI
D. USG (Correct Answer)

Explanation: ***USG*** - **Ultrasound** (USG), specifically **carotid duplex ultrasonography**, is the **safest**, most cost-effective, and readily available initial screening tool for carotid artery stenosis due to its non-invasive nature and ability to visualize blood flow and vessel morphology. - It combines **B-mode imaging** with **Doppler flow analysis** to provide real-time images and flow velocity measurements, allowing for assessment of the degree of **stenosis** and plaque characteristics without radiation or contrast agents. - Sensitivity and specificity exceed 85-90% for detecting significant stenosis, making it the preferred first-line screening modality. *Digital Subtraction Angiography (DSA)* - **DSA** is the **gold standard** for anatomical detail and remains the most accurate method for quantifying carotid stenosis, but it is **invasive** and requires arterial catheterization. - It involves **ionizing radiation** and **iodinated contrast agents**, carrying risks of stroke (0.5-1%), arterial dissection, nephrotoxicity, and contrast allergic reactions. - Due to its invasive nature and associated risks, DSA is reserved for **pre-surgical planning** or when non-invasive imaging is inconclusive, not for initial screening. *CT* - **Computed tomography angiography (CTA)** involves **ionizing radiation** and typically requires an **iodinated contrast agent**, which carries risks of allergy and nephrotoxicity. - Though CTA provides excellent anatomical detail and can visualize vessel wall calcification, it is generally reserved for confirmation or surgical planning rather than initial screening due to its higher cost, radiation exposure, and contrast-related risks. *MRI* - **Magnetic resonance angiography (MRA)** can visualize carotid arteries well but is more expensive, less accessible than ultrasound, and may require a **gadolinium-based contrast agent**, which can have adverse effects (nephrogenic systemic fibrosis in renal impairment). - It is often used when ultrasound findings are equivocal or in cases where CTA is contraindicated, but it's not the preferred initial screening method due to its complexity, cost, longer examination time, and contraindications (pacemakers, metallic implants).

Question 195: According to endoscopic ultrasound (EUS) criteria for chronic pancreatitis, the main pancreatic duct is considered dilated when its diameter is:

A. >1 mm
B. >2 mm
C. 1.5 mm
D. >3 mm (Correct Answer)

Explanation: A main pancreatic duct diameter **greater than 3 mm** is a significant endoscopic ultrasound (EUS) criterion for the diagnosis of **chronic pancreatitis**. This dilation indicates advanced disease and is often accompanied by other EUS features like **lobularity**, **hyperechoic foci/stranding**, and cysts. While a dilated pancreatic duct is indicative of chronic pancreatitis, a diameter of **>1 mm** is generally too small to be considered a definitive EUS criterion for significant disease. A main pancreatic duct diameter greater than 2 mm is often considered abnormal [1], but it's **not the established threshold** used in EUS criteria for chronic pancreatitis. A diameter of 1.5 mm is usually considered within the **normal range** for the main pancreatic duct in many clinical contexts.

Question 196: Focal and diffuse thickening of gallbladder wall with high amplitude reflections and 'comet tail' artifacts on USG suggest the diagnosis of –

A. Carcinoma of gall bladder
B. Adenomyomatosis (Correct Answer)
C. Cholesterolosis
D. Xanthogranulomatous cholecystitis

Explanation: ***Adenomyomatosis*** - This condition is characterized by **hyperplasia of the muscular layer** and **outpouchings of the mucosa** through the muscular wall (Rokitansky-Aschoff sinuses). - The thickened wall with **Rokitansky-Aschoff sinuses** containing bile or cholesterol crystals causes **high-amplitude reflections** and **comet tail artifacts** on ultrasound. *Carcinoma of gall bladder* - While carcinoma can also cause focal or diffuse thickening of the gallbladder wall, it typically appears as a **mass lesion** and **does not usually demonstrate comet-tail artifacts**. - **Comet-tail artifacts** are pathognomonic for **adenomyomatosis**, indicating gas, cholesterol crystals, or inspissated bile within Rokitansky-Aschoff sinuses. *Cholesterolosis* - This condition, also known as **strawberry gallbladder**, involves the deposition of **cholesterol esters in the lamina propria** of the gallbladder wall. - It usually presents as **multiple small polyps** on ultrasound, without the diffuse wall thickening or classic "comet tail" artifact seen with adenomyomatosis. *Xanthogranulomatous cholecystitis* - This is a rare, severe form of chronic cholecystitis characterized by **lipid-laden macrophages** and significant **fibrosis** in the gallbladder wall. - It causes **marked, diffuse mural thickening** or **nodular lesions** which can mimic carcinoma, but it typically **lacks the specific acoustic shadowing and comet tail artifacts** associated with adenomyomatosis.

Question 197: All are sonological features of Budd Chiari syndrome, EXCEPT:

A. Intraluminal echogenicity of hepatic vein
B. Stenosis and proximal dilatation of the hepatic veins
C. Thickened walls of hepatic vein
D. Diffusely dilated hepatic veins (Correct Answer)

Explanation: ***Diffusely dilated hepatic veins*** - **Diffusely dilated hepatic veins** are *not* a sonological feature of **Budd-Chiari syndrome**, as the primary pathology is **hepatic venous obstruction**, which leads to *narrowing, stenosis, or absence of flow* rather than generalized dilatation. - In Budd-Chiari syndrome, hepatic veins are typically **compressed, thrombosed, or stenotic**, not uniformly dilated throughout their course. - While **focal proximal dilatation** can occur upstream of a stenotic segment (see option below), **diffuse dilatation** of all hepatic veins is not characteristic of this condition. *Intraluminal echogenicity of hepatic vein* - **Intraluminal echogenicity** within the hepatic veins indicates the presence of **thrombus** or **fibrin**, which is a direct cause of **Budd-Chiari syndrome**. - This finding is crucial for diagnosing **acute hepatic venous thrombosis** and is a classic sonographic feature. *Stenosis and proximal dilatation of the hepatic veins* - **Stenosis** (narrowing) of the hepatic veins is a hallmark finding due to **thrombus formation**, **webs**, or **fibrosis** causing obstruction. - **Proximal dilatation** refers to localized dilation of the vein segment *upstream* from the point of obstruction as blood backs up, which is a classic sign of venous outflow obstruction. - This combination of focal stenosis with proximal dilatation is characteristic and different from diffuse dilatation of all veins. *Thickened walls of hepatic vein* - **Thickened walls** of the hepatic veins can be seen in **chronic Budd-Chiari syndrome** due to **inflammation** and **fibrosis** resulting from long-standing venous congestion and remodeling. - This finding suggests a more established or advanced stage of the disease.

Question 198: The four points of probe placement in focused abdominal sonogram for trauma (FAST) in thoracoabdominal trauma are

A. Hypogastrium, (R) and (L) lumbar region, (R) lower chest
B. Epigastrium, (R) and (L) lumbar region, (R) lower chest
C. Subxiphoid, (R) upper quadrant, (L) upper quadrant, suprapubic (Correct Answer)
D. Epigastrium, (R) and (L) hypochondria, (R) iliac fossa

Explanation: ***Subxiphoid, (R) upper quadrant, (L) upper quadrant, suprapubic*** - These four areas represent the standard views for a **FAST exam**, designed to detect **free fluid** in the most gravity-dependent and common spaces for accumulation within the abdomen and pericardium. - The **subxiphoid view** assesses the pericardial sac, the **right upper quadrant** evaluates Morrison's pouch, the **left upper quadrant** examines the splenorenal recess, and the **suprapubic view** checks the rectovesical or uterovesical pouch. *Hypogastrium, (R) and (L) lumbar region, (R) lower chest* - The **lumbar regions** are not primary or standard FAST windows due to anatomical complexity and lower fluid accumulation likelihood. - While the lower chest can be part of an extended FAST, the specified regions (right and left lumbar) are not the typical, most critical points for initial trauma assessment. *Epigastrium, (R) and (L) lumbar region, (R) lower chest* - The **epigastrium** is not a standard primary FAST window for free fluid; the subxiphoid view specifically targets the pericardium. - Again, the **lumbar regions** are not part of the core four FAST views for rapid detection of intraperitoneal hemorrhage. *Epigastrium, (R) and (L) hypochondria, (R) iliac fossa* - The terms **hypochondria** and **iliac fossa** are less precise than the specific anatomical spaces targeted by FAST (Morrison's pouch, splenorenal recess, pelvic cul-de-sac). - The **epigastrium** is not one of the four established primary FAST windows for free fluid in trauma.

Question 199: Ultrasound is the investigation of choice for

A. Somatostatinoma
B. Intraductal Pancreatic calculi
C. Urethral stricture
D. Blunt abdominal trauma (Correct Answer)

Explanation: ***Blunt abdominal trauma*** - **Focused Assessment with Sonography for Trauma (FAST) exam** is the initial imaging modality of choice for rapidly detecting **intra-abdominal free fluid** (hemoperitoneum) in hemodynamically unstable patients with blunt abdominal trauma due to its speed, portability, and non-invasiveness. - It helps guide the need for further imaging or surgical intervention, making it critical in the acute setting. *Somatostatinoma* - Diagnosed primarily through biochemical tests (elevated **somatostatin levels**) and imaging like **CT, MRI, or somatostatin receptor scintigraphy (SRS)**, which are superior for localizing these rare neuroendocrine tumors. - Although ultrasound can sometimes detect pancreatic masses, it is not the **investigation of choice** for definitive diagnosis or staging of somatostatinomas. *Intraductal Pancreatic calculi* - Often best visualized with **Endoscopic Retrograde Cholangiopancreatography (ERCP)** or **Magnetic Resonance Cholangiopancreatography (MRCP)**, which provide detailed imaging of the pancreatic and bile ducts. - While transabdominal ultrasound can sometimes detect dilated ducts or large calculi, **Endoscopic Ultrasound (EUS)** is more sensitive and specific for intraductal pathologies, making routine transabdominal ultrasound not the primary choice. *Urethral stricture* - The gold standard for diagnosing urethral strictures is **urethrography** (retrograde urethrogram), which directly visualizes the stricture and its extent. - While ultrasound can sometimes be used to assess the urethra, it is less effective than urethrography for defining the length and severity of a stricture.

Question 200: Best advantage of doing transcranial Doppler ultrasound?

A. Detect brain blood vessels stenosis
B. Detect AV malformation
C. Detect emboli
D. Detect vasospasm (Correct Answer)

Explanation: ***Detect vasospasm*** - **Transcranial Doppler (TCD) ultrasound** is highly effective for monitoring and detecting **cerebral vasospasm**, particularly after a **subarachnoid hemorrhage**. - It allows for non-invasive, continuous, and dynamic assessment of **blood flow velocities** in the **intracranial arteries**, which increase significantly during vasospasm. *Detect brain blood vessels stenosis* - While TCD can indicate increased flow velocities suggestive of **stenosis**, it is less accurate for precise anatomical localization and quantification compared to **CTA** or **MRA**. - Its ability to directly visualize the vessel lumen and the degree of stenosis is limited by its reliance on **flow dynamics**. *Detect AV malformation* - TCD can sometimes detect altered flow patterns associated with **arteriovenous malformations (AVMs)**, but it lacks the spatial resolution to definitively diagnose or characterize these complex vascular structures. - **Cerebral angiography** or **MRA** are the gold standards for diagnosing and mapping **AVMs**. *Detect emboli* - TCD can detect **microembolic signals (MES)**, which are transient high-intensity signals indicating the passage of emboli through the cerebral circulation. - However, while it can detect emboli, it is not its *best* or primary advantage compared to its utility in monitoring **vasospasm**, which directly impacts patient management and prognosis in certain acute conditions.

Practice by Chapter

Physics of Ultrasound

Practice Questions

Instrumentation and Techniques

Practice Questions

Abdominal Ultrasonography

Practice Questions

Pelvic Ultrasonography

Practice Questions

Obstetric Ultrasonography

Practice Questions

Small Parts Ultrasonography

Practice Questions

Musculoskeletal Ultrasonography

Practice Questions

Vascular Ultrasonography

Practice Questions

Pediatric Ultrasonography

Practice Questions

Contrast-Enhanced Ultrasound

Practice Questions

Ultrasound-Guided Interventions

Practice Questions

Doppler Ultrasound Principles and Applications

Practice Questions

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free

Ultrasound — MCQs

Ultrasound — MCQs

On this page

Practice by Chapter

Want unlimited practice?