Ultrasound — MCQs

Ultrasound Indian Medical PG Practice Questions and MCQs

Question 241: In acute pyelonephritis, which of the following is NOT a USG finding:

A. Increased vascularity (Correct Answer)
B. Renal enlargement
C. Increased echogenicity
D. Compression of the renal sinuses

Explanation: ***Increased vascularity*** - On **grayscale ultrasound**, vascularity assessment is limited, and acute pyelonephritis typically appears as areas of altered echogenicity without direct visualization of blood flow. - However, on **color Doppler ultrasound**, acute pyelonephritis typically shows **increased vascularity** (hyperemia) due to inflammatory response, NOT decreased vascularity. - The question likely refers to **conventional grayscale USG findings** where direct vascularity assessment is not the primary diagnostic feature, unlike CT or Doppler studies. - This option is considered "NOT a typical finding" in the context of **standard grayscale ultrasound examination** where other findings are more reliably demonstrated. *Renal enlargement* - **Renal enlargement** is a common and characteristic finding in acute pyelonephritis due to **edema and inflammation** of the renal parenchyma. - This enlargement is often diffuse but can be focal (focal pyelonephritis or lobar nephronia). *Increased echogenicity* - **Increased echogenicity** of the renal parenchyma is commonly observed in acute pyelonephritis due to **interstitial edema** and inflammatory cell infiltration. - May appear as focal or diffuse areas of altered echogenicity. *Compression of the renal sinuses* - **Compression of the renal sinuses** occurs in acute pyelonephritis as the **inflamed and swollen parenchyma** expands, compressing the echogenic fatty tissue within the central renal sinus. - This finding indicates significant **parenchymal swelling** and is a characteristic feature on ultrasound.

Question 242: In a clinical ultrasound assessment, what is considered the normal thickness of the stomach wall?

A. 2 mm
B. 5 mm (Correct Answer)
C. 8 mm
D. 10 mm

Explanation: ***5 mm*** - A stomach wall thickness of **5 mm** is generally considered the upper limit of normal in a clinical ultrasound assessment. - Measurements exceeding **5 mm** may indicate the presence of pathology such as inflammation, edema, or malignancy. *2 mm* - A stomach wall thickness of **2 mm** is typically considered at the lower end of the normal range, or even slightly thinner than average, especially in a distended stomach. - While not necessarily abnormal, it does not represent the upper limit for normal thickness. *8 mm* - A stomach wall thickness of **8 mm** is usually considered significantly thickened and indicative of an underlying pathological process. - This measurement would prompt further investigation for conditions like gastritis, ulceration, or neoplastic changes. *10 mm* - A stomach wall thickness of **10 mm** is a definite sign of abnormal thickening and strongly suggests a significant infiltrative or inflammatory process. - This degree of thickening is rarely, if ever, a normal finding and warrants immediate clinical attention.

Question 243: What is the main advantage of transesophageal echocardiography (TEE)?

A. Lung tumors can be diagnosed with TEE.
B. TEE can guide ECG procedures.
C. TEE is useful for lung biopsy procedures.
D. Superior imaging of cardiac structures for thrombus detection. (Correct Answer)

Explanation: ***Superior imaging of cardiac structures for thrombus detection.*** - TEE provides much **clearer images** of the heart, particularly the **atria** and **valves**, due to the proximity of the esophagus to these structures. - This enhanced visualization allows for the reliable detection of **intracardiac thrombi**, especially in the **left atrial appendage**, which is crucial before procedures like cardioversion. *Lung tumors can be diagnosed with TEE.* - While TEE can occasionally visualize mediastinal structures adjacent to the esophagus, it is **not the primary or most effective tool** for diagnosing **lung tumors**. - **CT scans** or **bronchoscopy** are superior imaging modalities for lung pathology. *TEE can guide ECG procedures.* - **ECG (electrocardiogram)** is a diagnostic tool that measures the electrical activity of the heart; it is not a procedure to be guided by imaging. - TEE is often used to guide certain **interventional cardiology procedures**, but not ECG. *TEE is useful for lung biopsy procedures.* - TEE is an **imaging technique for cardiac structures** and has no direct role in guiding **lung biopsy procedures**. - **CT-guided biopsy** or **bronchoscopy** are the standard methods for lung biopsies.

Question 244: What is the primary advantage of using sector scanning in neonates?

A. Cost-effective imaging technique
B. Higher resolution images
C. Allows for better imaging through open fontanelles (Correct Answer)
D. Increased cooperation from patients

Explanation: ***Allows for better imaging through open fontanelles*** - **Sector scanning** utilizes a small footprint transducer that can fit through the **open fontanelles** of neonates, providing an acoustic window to the brain. - This method is crucial for **neurosonography** in infants, as the fontanelles allow the ultrasound waves to bypass the calcified skull, which would otherwise block the sound waves. *Cost-effective imaging technique* - While **ultrasound** can be cost-effective compared to other modalities like MRI, this is a general advantage of ultrasound and not the **primary advantage specific to sector scanning in neonates**. - The main benefit in neonates is the anatomical access provided by the transducer shape through fontanelles, rather than just cost. *Higher resolution images* - **Higher resolution** generally correlates with higher frequency transducers, but sector scanners themselves aren't inherently superior in resolution compared to other types of transducers (e.g., linear array) for all applications. - The resolution depends more on the transducer frequency and imaging technology rather than the **sector scanning** method's primary advantage in neonates, which is access. *Increased cooperation from patients* - **Infants** and neonates often have limited cooperation regardless of the imaging technique. - The ability to image through fontanelles reduces the need for extensive patient cooperation, but this is a consequence of the technical advantage rather than the primary goal or mechanism of **sector scanning**.

Question 245: What is the frequency range of ultrasonic sound waves used in medical sonography?

A. 2 - 20 MHz (Correct Answer)
B. Less than 1 MHz
C. 20 - 20,000 Hz
D. Greater than 100 MHz

Explanation: ***2 - 20 MHz*** - Medical sonography utilizes **ultrasound waves**, which are sound waves with frequencies **above the human hearing range**. - The typical frequency range for diagnostic medical applications is between **2 and 20 megahertz (MHz)**, balancing penetration depth and image resolution. *Less than 1 MHz* - Frequencies **below 1 MHz** would offer very high penetration but **poor resolution**, making them unsuitable for detailed diagnostic imaging. - These lower frequencies are more characteristic of **therapeutic ultrasound** applications, which aim to heat tissues, rather than create images. *20 - 20,000 Hz* - This range represents the **audible spectrum of human hearing** and is not used for medical imaging. - Sound waves within this range are detected by the human ear and are too low in frequency to generate medically useful images. *Greater than 100 MHz* - While offering extremely high resolution, frequencies **above 100 MHz** have **very limited penetration** into biological tissues. - These ultra-high frequencies are primarily used in **research settings** for microscopic imaging of superficial structures, not for general diagnostic sonography.

Question 246: Investigation of choice for hypertrophic pyloric stenosis is

A. USG (Correct Answer)
B. X-ray
C. CT
D. MRI

Explanation: ***USG*** - **Ultrasound** is the preferred imaging modality for diagnosing **hypertrophic pyloric stenosis** due to its non-invasive nature, lack of radiation, and ability to directly visualize the thickened pyloric muscle. - Diagnostic criteria on ultrasound include a **pyloric muscle thickness** greater than 3-4 mm and a **pyloric channel length** greater than 14-17 mm. *X-ray* - An **X-ray** may show a dilated stomach with a **small amount of gas** in the distal bowel, but it is not specific for hypertrophic pyloric stenosis and cannot directly visualize the pylorus. - Barium studies (upper GI series) were historically used but have largely been replaced by ultrasound due to **radiation exposure** and diagnostic inferiority. *CT* - **CT scans** involve significant **radiation exposure** and are generally not recommended for infants due to risks, especially when a definitive diagnosis can be made effectively with ultrasound. - While CT can visualize the pylorus, it offers no significant advantage over ultrasound for this specific condition and carries **higher risks**. *MRI* - **MRI** is a sophisticated imaging technique that offers excellent soft tissue contrast, but it is **time-consuming**, expensive, and often requires sedation in infants. - It is not the investigation of choice for hypertrophic pyloric stenosis where **ultrasound is readily available** and provides sufficient diagnostic information without sedation or radiation.

Question 247: Which of the following is typically seen on ultrasound in acute pyelonephritis?

A. Decreased vascularity
B. Enlarged kidney with diffuse swelling (Correct Answer)
C. Localized hypoechogenic areas in the kidney
D. Fluid collection around the kidney

Explanation: ***Enlarged kidney with diffuse swelling*** - In **acute pyelonephritis**, the **most consistent ultrasound finding** is **renal enlargement** with **diffuse swelling** of the affected kidney. - This occurs due to **inflammatory edema** and increased fluid content within the renal parenchyma, representing the body's inflammatory response to infection. - **Diffuse enlargement** is present in the majority of cases and is often the **earliest sonographic manifestation**, making it the most typical finding. *Localized hypoechogenic areas in the kidney* - **Focal or multifocal hypoechoic areas** are indeed **highly characteristic** of acute pyelonephritis and represent zones of **parenchymal edema and inflammation**. - These are seen in approximately **20-80% of cases** and are considered a hallmark feature. - However, they may not be present in all cases, particularly in early or mild disease, whereas **renal enlargement is more consistently present**. - When visible, these areas have high specificity for the diagnosis. *Fluid collection around the kidney* - **Perinephric fluid collections** or abscesses indicate **complicated pyelonephritis** with extension of infection beyond the renal capsule. - These are **not typical findings in uncomplicated acute pyelonephritis** and suggest more severe or advanced infection requiring aggressive management. *Decreased vascularity* - Acute pyelonephritis typically shows **increased vascularity** on color Doppler due to **hyperemia and inflammatory vasodilation**. - **Decreased vascularity** is associated with **renal infarction**, severe ischemia, or chronic scarring—not acute bacterial infection.

Question 248: What is the investigation of choice for an 8-year-old child presenting with an acute abdomen?

A. USG (Correct Answer)
B. CT Scan
C. X-ray
D. MRI

Explanation: ***USG*** - An **ultrasound (USG)** is the preferred initial imaging modality in pediatric acute abdomen due to its **lack of ionizing radiation**, ease of use, and ability to visualize common causes like appendicitis and intussusception. - It is particularly useful for assessing **fluid collections**, inflammation, and obstruction in a non-invasive manner suitable for children. *CT Scan* - While it offers detailed anatomical views, **CT scans** involve significant **ionizing radiation**, which is a concern in children due to increased lifetime cancer risk. - It is typically reserved for cases where **USG is inconclusive** or if there is a high suspicion of conditions not well visualized by ultrasound. *X-ray* - **X-rays** provide limited information for soft tissue pathologies and are primarily useful for detecting **bowel obstruction (air-fluid levels)** or **free air** (perforation). - They lack the resolution to diagnose many common causes of acute abdomen in children, such as appendicitis or intussusception. *MRI* - **MRI** provides excellent soft tissue contrast without ionizing radiation but often requires **sedation** in young children due to the long scan times and need for stillness. - It is less readily available and more expensive than USG, making it a less practical first-line investigation for an acute presentation.

Question 249: What is the investigation of choice for evaluating biliary pathology?

A. Contrast enhanced CT abdomen
B. Duplex Doppler of the abdomen
C. MRI scan of the abdomen
D. USG of abdomen (Correct Answer)

Explanation: ***USG of abdomen*** - **Ultrasound (USG)** of the abdomen is the initial and often definitive investigation for biliary pathology due to its **non-invasiveness**, **accessibility**, and ability to visualize gallstones, duct dilation, and inflamed gallbladder walls. - It is highly sensitive for detecting **cholelithiasis**, **cholecystitis**, and common bile duct obstruction, making it the preferred first-line imaging modality. *Contrast enhanced CT abdomen* - While useful for evaluating solid organ pathology and detecting complications, **CT scans** are less sensitive than USG for visualizing gallstones and assessing subtle biliary duct changes. - CT involves **ionizing radiation** and the use of contrast agents, which are not ideal for initial screening or if radiation exposure is a concern. *Duplex Doppler of the abdomen* - **Duplex Doppler** primarily assesses **vascular flow** and is useful for evaluating conditions like portal hypertension or vascular anomalies. - It has limited utility for directly visualizing the biliary tree or detecting gallstones, and thus is not the investigation of choice for biliary pathology. *MRI scan of the abdomen* - **MRI** is an excellent tool for detailed imaging of the biliary tree, especially with **Magnetic Resonance Cholangiopancreatography (MRCP)**, which provides detailed images of the bile ducts without contrast. - However, MRI is typically reserved for cases where USG findings are inconclusive or when more detailed anatomical information is required, as it is more expensive and less readily available than USG.

Question 250: Which of the following structures is LEAST suitable for ultrasound visualization?

A. Lungs
B. Bone marrow
C. Bone (Correct Answer)
D. Air

Explanation: ***Bone*** - The dense, calcified matrix of bone causes significant **reflection and attenuation** of ultrasound waves. - This property prevents sound waves from penetrating into or through bone, making internal structures like **bone marrow** or features within the bone itself **impossible to visualize**. - Bone is the **LEAST suitable structure** for ultrasound because it completely blocks visualization of anything deeper, and only its superficial surface can be seen as a bright echogenic line. *Air* - Air is a very poor conductor of ultrasound waves, causing almost complete **reflection** (~99.9%) at an air-tissue interface. - This creates strong **acoustic impedance mismatch** and produces reverberation artifacts. - This principle is why acoustic gel is used during ultrasound exams – to eliminate the air interface between the transducer and the skin. - While air creates severe artifacts, it's more of an **interface problem** than a structural visualization challenge. *Lungs* - The presence of air within the lung parenchyma significantly **scatters ultrasound waves**, limiting direct visualization of normal aerated lung tissue. - While ultrasound can be used to assess the **pleura**, detect **pleural effusions**, **pneumothorax**, or **consolidation**, it's generally poor for imaging normal aerated lung tissue. - Lung ultrasound has specific clinical applications despite these limitations. *Bone marrow* - While bone marrow is surrounded by bone making direct ultrasound visualization challenging, it's the bone cortex that blocks the ultrasound, not the marrow itself. - Direct, detailed imaging of marrow abnormalities is usually performed using **MRI** or **CT**. - Bone marrow is inaccessible primarily because of the surrounding bone barrier.

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Physics of Ultrasound

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Instrumentation and Techniques

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Abdominal Ultrasonography

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Pelvic Ultrasonography

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Obstetric Ultrasonography

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Small Parts Ultrasonography

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Musculoskeletal Ultrasonography

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Vascular Ultrasonography

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Pediatric Ultrasonography

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Contrast-Enhanced Ultrasound

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Ultrasound-Guided Interventions

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Doppler Ultrasound Principles and Applications

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Ultrasound — MCQs

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