Abdominal Ultrasonography — MCQs
Which of the following structures is LEAST suitable for ultrasound visualization?
A patient with known cirrhosis presents with jaundice and abdominal distention. Ultrasound reveals ascites and splenomegaly. What is the most likely cause of his ascites?
Which of the following is best assessed by FAST USG?
What is the investigation of choice for blunt abdominal trauma in an unstable patient?
Which is not echogenic while doing ultrasonography:
An ultrasound examination shows dilated intrahepatic biliary channels with a small gallbladder. The most likely possibility is
Best diagnostic aid in blunt trauma abdomen is -
What is the Diagnosis based on the CT Scan given below?
In an ultrasound of the abdomen, which structure is best seen posterior to the stomach?
Ultrasound is the investigation of choice for
Abdominal Ultrasonography Indian Medical PG Practice Questions and MCQs
Question 1: 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.
Question 2: A patient with known cirrhosis presents with jaundice and abdominal distention. Ultrasound reveals ascites and splenomegaly. What is the most likely cause of his ascites?
- A. Portal hypertension (Correct Answer)
- B. Peritoneal carcinomatosis
- C. Nephrotic syndrome
- D. Congestive heart failure
Explanation: ***Portal hypertension*** - In cirrhosis, **fibrosis** and **regenerative nodules** increase resistance to blood flow through the liver, leading to **portal hypertension** [1]. - This increased pressure in the portal venous system, combined with **splanchnic vasodilation** and **renal sodium retention**, drives the transudation of fluid into the peritoneal cavity, forming ascites [1]. *Peritoneal carcinomatosis* - This would typically result in **exudative ascites**, often with a high protein content and positive cytology for malignant cells [1]. - While it can cause abdominal distention, it is not directly linked to the pathology of **cirrhosis** and **splenomegaly** as the primary cause of ascites in this context. *Nephrotic syndrome* - Characterized by **massive proteinuria**, **hypoalbuminemia**, and **generalized edema**, including ascites. - While it causes fluid retention, the clinical picture of **jaundice** and **splenomegaly** strongly points to liver pathology rather than primary renal disease [1]. *Congestive heart failure* - Can cause **dependent edema** and ascites due to elevated systemic venous pressures, but typically presents with other signs like **dyspnea**, orthopnea, and pulmonary edema [1]. - The patient's history of **cirrhosis** and the presence of **splenomegaly** make portal hypertension a significantly more likely cause of ascites [1].
Question 3: Which of the following is best assessed by FAST USG?
- A. Liver
- B. Pericardium (Correct Answer)
- C. Spleen
- D. Pleural cavity
Explanation: ***Pericardium*** - FAST USG is **most clinically significant** for detecting **pericardial effusions** and **cardiac tamponade** in trauma patients. - The **subxiphoid view** provides **excellent direct visualization** of the heart and pericardial space with minimal interference. - **Small volumes** of pericardial fluid (as little as 50-100 mL) are **clinically significant** and potentially life-threatening, requiring immediate intervention. - Cardiac tamponade is an **immediately reversible cause of shock** that demands urgent diagnosis and pericardiocentesis. - **Sensitivity >90%** for clinically significant pericardial effusions in the trauma setting. *Liver* - FAST assesses the **hepatorenal space (Morison's pouch)** for free fluid, not the liver parenchyma itself. - Requires **larger volumes of free fluid** (>200-500 mL) to be reliably detected in the peritoneal cavity. - Detailed assessment of actual liver injury requires **contrast-enhanced CT imaging**. *Spleen* - FAST evaluates the **splenorenal recess** for free fluid surrounding the spleen, not splenic parenchymal injury. - Detection depends on adequate volume of free fluid being present. - **CT scanning** is superior for defining splenic lacerations, hematomas, and grading injury severity. *Pleural cavity* - While Extended FAST (eFAST) can assess **pleural spaces** for effusion or pneumothorax, this is an **extension** of the standard 4-view FAST protocol. - Standard FAST focuses on the **four primary windows**: pericardial, perihepatic, perisplenic, and pelvic. - **Chest X-ray** and **CT** remain primary modalities for comprehensive thoracic assessment.
Question 4: What is the investigation of choice for blunt abdominal trauma in an unstable patient?
- A. X-ray abdomen
- B. MRI
- C. USG (Correct Answer)
- D. Diagnostic Peritoneal Lavage (DPL)
Explanation: ***USG (FAST Exam)*** - In an **unstable patient** with blunt abdominal trauma, **Focused Assessment with Sonography for Trauma (FAST) exam** is the investigation of choice. - It is **rapid, non-invasive, and bedside**, allowing immediate detection of **free fluid** (blood) in the peritoneal cavity, pericardium, and pleural spaces without transporting the patient. - Guides immediate decision for **laparotomy** in hemodynamically unstable patients. - **Note:** In **stable patients**, **CT abdomen** is the gold standard as it provides detailed anatomical information, but it requires patient transport and time. *X-ray abdomen* - Provides limited information in blunt trauma, primarily showing **free air** (bowel perforation) or **bony fractures**. - **Not sensitive** for detecting intraperitoneal bleeding, which is the primary concern in unstable patients. *MRI* - Offers excellent soft tissue detail but is **time-consuming** and requires the patient to be **hemodynamically stable**. - **Impractical** for unstable trauma patients requiring rapid assessment and intervention. *Diagnostic Peritoneal Lavage (DPL)* - An **invasive procedure** that is sensitive for detecting intra-abdominal hemorrhage. - Has largely been **replaced by FAST exam** in most trauma centers due to FAST being non-invasive, rapid, and repeatable. - DPL has a **higher false-positive rate** and cannot identify the source of bleeding.
Question 5: Which is not echogenic while doing ultrasonography:
- A. Bile (Correct Answer)
- B. Bone
- C. Gas
- D. Gall stones
Explanation: ***Bile*** - Bile is largely composed of **water**, which allows ultrasound waves to pass through it with minimal reflection, appearing **anechoic** (black) on ultrasound. - This property makes the gallbladder lumen, when filled with bile, appear anechoic, which is crucial for identifying structures like gallstones. *Bone* - **Bone** is highly dense and reflects a significant portion of ultrasound waves, making it appear very **echogenic** (bright) on ultrasonography. - Due to its high reflectivity, bone often produces a strong **acoustic shadow** behind it, obscuring deeper structures. *Gas* - **Gas** (air) is a strong reflector of ultrasound waves and appears brightly echogenic, often with a characteristic **dirty shadowing** or **reverberation artifact**. - The presence of gas can significantly hinder visualization of underlying tissues due to its strong reflection and scatter of the ultrasound beam. *Gall stones* - **Gallstones** are solid concretions that are highly reflective of ultrasound waves, appearing as bright, **echogenic foci** within the gallbladder lumen. - A classic ultrasound sign of gallstones is an echogenic structure with strong **posterior acoustic shadowing**.
Question 6: An ultrasound examination shows dilated intrahepatic biliary channels with a small gallbladder. The most likely possibility is
- A. Carcinoma of the head of the pancreas
- B. Pancreatic calculus
- C. Gallbladder stones
- D. Common bile duct stone (Correct Answer)
Explanation: ***Common bile duct stone*** - A **common bile duct (CBD) stone** obstructing flow can cause **intrahepatic biliary dilation** as bile backs up into the liver. - A **small, non-distended gallbladder** suggests that the obstruction is distal to the cystic duct, preventing bile entry into the gallbladder or causing it to contract in response to a partial obstruction. *Carcinoma of the head of the pancreas* - Pancreatic head carcinoma typically causes **Courvoisier's sign**, characterized by a **palpable, non-tender, distended gallbladder** due to chronic, progressive obstruction of the distal CBD. - While it causes intrahepatic ductal dilation, the gallbladder usually appears distended, not small. *Pancreatic calculus* - A pancreatic calculus typically causes **pancreatitis** or **pain**, and may lead to **dilation of the pancreatic duct**, not primarily the biliary tree. - Unless directly causing CBD obstruction, it would not explain dilated intrahepatic biliary channels with a small gallbladder. *Gallbladder stones* - **Gallbladder stones** typically cause **cholecystitis** or **biliary colic**, and if they obstruct the cystic duct, they can cause a **distended gallbladder**. - They do not typically cause widespread intrahepatic biliary dilation unless they migrate into the common bile duct and cause obstruction there.
Question 7: Best diagnostic aid in blunt trauma abdomen is -
- A. Peritoneal lavage
- B. Ultrasound (Correct Answer)
- C. 4 quadrant aspiration
- D. CT scan
Explanation: ***Ultrasound (FAST)*** - **Focused Assessment with Sonography for Trauma (FAST)** is considered the **best initial diagnostic aid** in blunt abdominal trauma due to its **speed, availability, and versatility**. - It is **rapid, non-invasive, repeatable**, and can be performed **at the bedside** during resuscitation without moving the patient. - Highly sensitive for detecting **free intraperitoneal fluid** (blood) and **pericardial effusion**, which are critical in hemodynamically unstable patients. - Can be performed by **emergency physicians and surgeons** with minimal training, making it universally applicable in trauma settings. - **ATLS protocol** recommends FAST as the primary screening tool in the trauma bay. *CT scan* - **CT scan** provides the **most detailed anatomical information** and is the gold standard for evaluating **solid organ injuries** and **retroperitoneal hemorrhage** in **hemodynamically stable** patients. - However, it requires **patient transport**, involves **radiation exposure**, is **time-consuming**, and is **not suitable for unstable patients**. - Reserved for stable patients where detailed injury characterization is needed for non-operative management decisions. *Peritoneal lavage* - **Diagnostic peritoneal lavage (DPL)** was historically used but is **highly invasive** with a high rate of **non-therapeutic laparotomies**. - Largely **replaced by FAST ultrasound** due to better specificity and non-invasive nature. - Still occasionally used when FAST and CT are unavailable or inconclusive. *4 quadrant aspiration* - **Four-quadrant aspiration** (diagnostic paracentesis) has **poor sensitivity** for detecting intra-abdominal injuries. - **Rarely used** in modern trauma care due to **limited diagnostic yield** and risk of **iatrogenic injury**. - Superseded by more reliable modalities like FAST and CT.
Question 8: What is the Diagnosis based on the CT Scan given below?
- A. Renal cyst
- B. Renal tumor
- C. Renal polycystic kidney disease (Correct Answer)
- D. Renal angiomyolipoma
Explanation: ***Polycystic kidney disease*** - The CT scan images show **enlarged kidneys** replaced by numerous **cysts of varying sizes**, which is the hallmark appearance of polycystic kidney disease. - The presence of multiple cysts **bilaterally** and diffusely throughout the renal parenchyma is characteristic of this genetic disorder. *Renal cyst* - A single renal cyst is a common benign finding, appearing as a **well-defined, fluid-filled** structure. - The images clearly demonstrate **multiple cysts** affecting both kidneys, ruling out a solitary renal cyst. *Renal tumor* - A renal tumor (e.g., renal cell carcinoma) typically appears as a **solid mass**, often with heterogeneous enhancement after contrast. - The lesions seen in the image are predominantly **cystic** and multifocal, which is inconsistent with a typical renal tumor. *Renal angiomyolipoma* - Renal angiomyolipomas are benign tumors containing **fat, smooth muscle, and blood vessels**, and they characteristically show **macroscopic fat** on CT scans. - While they can be multiple, especially in tuberous sclerosis, the dominant feature in the image is widespread cystic transformation, not fat-containing solid masses.
Question 9: In an ultrasound of the abdomen, which structure is best seen posterior to the stomach?
- A. Pancreas (Correct Answer)
- B. Gallbladder
- C. Spleen
- D. Liver
Explanation: ***Pancreas*** - The **pancreas** is retroperitoneal and lies transversely across the posterior abdominal wall, making it located directly posterior to the stomach. - In ultrasound, the stomach, when filled with fluid, can act as an acoustic window to visualize the pancreas behind it. *Gallbladder* - The **gallbladder** is typically nestled in a fossa on the inferior surface of the liver, anterior to the duodenum and often anterior or inferior to the stomach [1]. - It is not positioned directly posterior to the stomach, but rather more to the right and inferior [1]. *Spleen* - The **spleen** is located in the left upper quadrant, superior and posterior to the stomach, but typically more lateral and posterior than directly behind it. - While it has a close relationship with the stomach, it is usually not considered "best seen posterior to the stomach" in the same straight-on fashion as the pancreas. *Liver* - The **liver** is primarily located in the right upper quadrant, largely anterior and superior to the stomach. - While a small portion of the left lobe of the liver can be anterior to the stomach, the bulk of the liver is not posterior to it.
Question 10: 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.
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