Abdominal and Pelvic Radiology Practice Questions

Q: A 25-year-old female presents with abdominal pain. An MRI shows a lesion with high T2 signal intensity and low T1 signal in the liver. What is the most likely diagnosis?

Hepatic cyst. ***Hepatic cyst*** - A **hepatic cyst** is a benign, fluid-filled lesion that typically demonstrates **high signal intensity on T2-weighted MRI** sequences and **low signal intensity on T1-weighted MRI** sequences due to its simple fluid content. - The absence of internal septations, solid components, or enhancement on post-contrast imaging further supports the diagnosis of a simple cyst. *Hepatic hemangioma* - While often showing **high signal on T2-weighted MRI**, hemangiomas typically exhibit a characteristic **peripheral nodular enhancement** during the arterial phase, with progressive filling in on delayed phases. - They tend to have **intermediate to high signal on T1-weighted MRI**, which is not consistent with the low T1 signal described. *Hepatocellular carcinoma* - **Hepatocellular carcinoma (HCC)** usually presents with **variable signal intensity** on both T1 and T2-weighted MRI, and classically shows **arterial phase hyperenhancement with venous washout**. - Its appearance is much more complex, often with internal heterogeneity, unlike the simple fluid signal described. *Focal nodular hyperplasia* - **Focal nodular hyperplasia (FNH)** typically has **isointense to slightly hyperintense signal** on both T1 and T2-weighted MRI and features a characteristic **central scar** that becomes hyperintense on delayed T2 images. - FNH shows bright, homogeneous enhancement in the arterial phase with rapid washout, and the central scar enhances late.

Q: A patient presents with symptoms of bowel obstruction. An abdominal X-ray shows multiple air-fluid levels. Which of the following additional imaging studies is most appropriate to determine the cause?

CT scan of the abdomen and pelvis. ***CT scan of the abdomen and pelvis*** - A **CT scan** is the gold standard for diagnosing the cause and level of bowel obstruction due to its detailed imaging capabilities. - It can identify the specific **etiology** (e.g., adhesions, tumor, hernia) and differentiate between partial and complete obstruction. *MRI of the abdomen* - While MRI provides excellent soft tissue contrast, it is generally less accessible and more time-consuming than CT for an acute presentation like bowel obstruction. - MRI is often reserved for special cases, such as in pregnant patients to avoid **radiation exposure**, or for evaluating complex pelvic pathologies. *Barium enema* - A **barium enema** is a fluoroscopic study primarily used to visualize the **colon** and **rectum**, and is useful for detecting distal obstructions like colonic strictures or tumors. - It is less effective for evaluating the small bowel or identifying the cause of obstruction in the upper gastrointestinal tract, and can be contraindicated in cases of suspected perforation. *Ultrasound of the abdomen* - **Ultrasound** can detect dilated bowel loops and some causes of obstruction (e.g., intussusception in children, gallstone ileus), but it is often limited by **bowel gas** and operator dependency. - It is generally not as comprehensive as CT for definitively identifying the precise location and cause of an adult small or large bowel obstruction.

Q: What is the imaging finding of barium studies in Crohn's disease?

String sign. ***String sign*** - The **string sign** is a classic finding in Crohn's disease on barium studies, representing severe narrowing of the bowel lumen due to **mural inflammation and fibrosis**. - This appearance is often seen in the **terminal ileum**, which is a common site of Crohn's involvement, and indicates a stenosis that resembles a thin string of barium. *Apple core lesion* - An **apple core lesion**, or napkin-ring sign, is characteristic of an **annular constricting carcinoma of the colon**. - It describes a circumferential narrowing of the bowel lumen with overhanging edges, distinct from the linear narrowing of Crohn's. *Bird beak sign* - The **bird beak sign** is typically associated with **achalasia**, a disorder of esophageal motility. - It describes the smooth, tapered narrowing of the distal esophagus, resembling a bird's beak, due to failure of the lower esophageal sphincter to relax. *Coiled spring appearance* - The **coiled spring appearance** is a classic radiographic sign of **intussusception**, where one segment of the bowel telescopes into another. - This finding is seen on barium or air enema studies and reflects the barium trapped between the layers of intussuscepted bowel.

Q: The initial imaging investigation for suspected intestinal obstruction is?

X-ray abdomen. ***Correct: X-ray abdomen*** - An **X-ray of the abdomen** is usually the **initial imaging investigation** due to its widespread availability, low cost, and ability to quickly identify signs of obstruction like **dilated bowel loops** and **air-fluid levels**. - While not as sensitive or specific as a CT scan, it serves as a crucial **first-line diagnostic tool** to determine the presence of an obstruction and guide further workup. *Incorrect: Ultrasound* - Ultrasound can be useful, especially in specific scenarios like suspected **intussusception** in children or **pyloric stenosis**. - However, its diagnostic accuracy for general intestinal obstruction in adults is often limited by **bowel gas** and operator dependence, making it less ideal as the initial test compared to X-ray. *Incorrect: CT scan* - A **CT scan with intravenous and oral contrast** is considered the **gold standard** for diagnosing intestinal obstruction, precisely localizing the obstruction, and identifying its cause. - It is typically performed **after an initial X-ray** has confirmed suspicion or as a primary investigation if an X-ray is inconclusive or complex pathology is suspected from the outset. *Incorrect: Barium study* - **Barium studies** (e.g., small bowel follow-through) involve administering contrast orally or rectally to visualize the bowel lumen. - While historically used, they are generally **avoided in suspected acute obstruction** due to the risk of barium impaction proximal to the obstruction or peritonitis if a perforation is present.

Q: A 70-year-old male presents with a pulsatile abdominal mass. Which diagnostic study is most appropriate to confirm the presence of an abdominal aortic aneurysm?

Abdominal ultrasound. ***Abdominal ultrasound*** - An abdominal ultrasound is the **initial and most appropriate diagnostic study** due to its non-invasive nature, accessibility, and high accuracy in visualizing the **aorta's diameter** and presence of a pulsatile mass. - It can effectively **measure the size of the aneurysm**, detect its presence, and monitor its progression over time. *CT angiography* - While **CT angiography** provides detailed anatomical information, it involves **ionizing radiation** and **contrast dye**, making it a less preferred initial diagnostic tool compared to ultrasound for screening or initial confirmation. - It is typically reserved for **surgical planning** or in cases where ultrasound findings are inconclusive, or more detailed vascular mapping is required. *MRI* - **MRI** is an excellent imaging modality for soft tissue and vascular structures but is generally **more expensive and time-consuming** than ultrasound, and less readily available, making it less suitable as a first-line diagnostic test for AAA. - Its use is often limited to patients who cannot undergo CT due to **renal insufficiency** or **contrast allergy**. *Plain X-ray* - A **plain X-ray** of the abdomen is **not sensitive** or specific enough to accurately diagnose or rule out an abdominal aortic aneurysm. - It may incidentally show **aortic calcification**, but it cannot reliably measure the aortic diameter or confirm an aneurysm.

Q: A 50-year-old female presents with abdominal pain and jaundice. An MRI reveals multiple liver lesions with a 'target' appearance. What is the most likely diagnosis?

Liver metastases. ***Liver metastases*** - The "target" or "bull's eye" appearance on MRI is a **classic radiological sign** for **liver metastases**, particularly from colon, lung, or breast cancers [1]. - **Abdominal pain** and **jaundice** in a 50-year-old female are significant symptoms that raise concern for advanced disease, potentially obstructive due to metastatic involvement of the biliary tree [1], [2]. *Hepatic cysts* - Hepatic cysts typically appear as well-defined, **anechoic (fluid-filled)** lesions on ultrasound or T2-hyperintense with thin walls on MRI, without a "target" appearance. - They are usually **asymptomatic** unless very large, or causing obstruction, and do not typically present with jaundice unless compressing the bile ducts directly. *Hepatocellular carcinoma* - HCC often presents as a **solitary mass** or multifocal lesions, typically showing characteristic **arterial enhancement** and **venous washout** on dynamic imaging, not usually a "target" appearance. - While HCC can cause abdominal pain and jaundice, the "target" sign is far more suggestive of metastatic disease [1]. *Focal nodular hyperplasia* - FNH is a **benign liver lesion** characterized by a **central stellate scar** and typically shows homogeneous enhancement on arterial phase with iso- or hyperintensity on portal venous phase, distinct from a "target" appearance. - It is usually **asymptomatic** and discovered incidentally; therefore, it is less likely to cause abdominal pain and jaundice.

Q: Which imaging technique is essential for evaluating a suspected perforation of the gastrointestinal tract?

CT scan with IV contrast. ***CT scan with IV contrast*** - A **CT scan with intravenous (IV) contrast** is the most sensitive and specific imaging modality for detecting **gastrointestinal (GI) perforation**. - It can visualize **free air**, fluid collections, and the site of perforation, providing crucial information for surgical planning. *Abdominal ultrasound* - While useful for detecting **free fluid** or abscesses, **abdominal ultrasound** is less sensitive for identifying **free air** in the abdomen, which is a hallmark of perforation. - Its diagnostic accuracy depends heavily on the operator's skill and patient body habitus. *X-ray using oral contrast* - An **X-ray using oral contrast** (e.g., gastrografin) can demonstrate a leak if the contrast extravasates, but it is less sensitive for small perforations and can be time-consuming. - Oral contrast is contraindicated if there's a risk of aspiration in an unstable patient, or if there is a known large perforation where the contrast could enter the peritoneal cavity and cause peritonitis. *MRI of the abdomen* - **MRI of the abdomen** is generally not the first-line imaging technique for acute GI perforation due to its longer acquisition times and higher cost. - Although it can detect **free fluid** and inflammation, it is not as readily available or as rapid as a CT scan, which is critical in an emergency setting.

Q: A patient with fever, back pain, and difficulty walking is diagnosed with a psoas abscess. Which imaging modality is the most effective for confirming the diagnosis?

CT scan. ***CT scan*** - **CT scan** is the **most effective** imaging modality for diagnosing a psoas abscess due to its superior ability to visualize deep soft tissue structures and precisely delineate the abscess. - It clearly shows the **inflammation**, fluid collection, and extension of the abscess, guiding potential drainage. *Ultrasound* - While useful for superficial collections, **ultrasound** has limited penetration and is often obscured by bowel gas, making it less effective for deep structures like the psoas muscle. - It may be used as a **bedside tool** for initial assessment or guided aspiration if the abscess is readily accessible. *X-ray* - **X-rays** have very limited utility in diagnosing psoas abscesses as they primarily visualize bony structures and cannot effectively delineate soft tissue collections. - They might show indirect signs like **loss of the psoas shadow**, but this is non-specific and insensitive. *MRI* - **MRI** provides excellent soft tissue contrast and is highly sensitive for detecting abscesses, but it is typically reserved for cases where CT is inconclusive or when there is a need to rule out spinal involvement. - It is **more expensive** and less readily available than CT, making it a secondary option for initial diagnosis.

Q: What is the first-line imaging modality for suspected appendicitis in a young adult?

Ultrasound of the abdomen. ***Ultrasound of the abdomen*** - **Ultrasound** is often the first-line imaging modality for suspected appendicitis, especially in young adults and children, due to its **non-invasive nature** and **lack of ionizing radiation**. - It can effectively visualize a **dilated, non-compressible appendix** with target sign, periappendiceal fluid, and increased vascularity. *X-ray abdomen* - **X-rays** are generally not useful for diagnosing appendicitis as they cannot visualize the appendix directly and offer **limited soft tissue detail**. - They may show secondary signs like a **fecalith** or localized ileus but are not diagnostic for appendicitis itself. *CT scan of the abdomen* - While highly sensitive and specific for appendicitis, **CT scans** involve significant **ionizing radiation**, making them a second-line option, especially for young adults where radiation exposure should be minimized. - CT is typically reserved for cases where ultrasound findings are inconclusive or when complications like **abscess formation** are suspected. *MRI of the abdomen* - **MRI** is an excellent modality for visualizing the appendix without radiation but is generally **less available**, more expensive, and **time-consuming** than ultrasound. - It is typically reserved for pregnant patients or those with **contraindications to CT contrast**, rather than as a first-line option in young adults.

Question 1

A 25-year-old female presents with abdominal pain. An MRI shows a lesion with high T2 signal intensity and low T1 signal in the liver. What is the most likely diagnosis?

Accepted Answer

Hepatic cyst

Answer

Hepatic hemangioma

Answer

Hepatocellular carcinoma

Answer

Focal nodular hyperplasia

Question 2

A patient presents with symptoms of bowel obstruction. An abdominal X-ray shows multiple air-fluid levels. Which of the following additional imaging studies is most appropriate to determine the cause?

Accepted Answer

CT scan of the abdomen and pelvis

Answer

MRI of the abdomen

Answer

Barium enema

Answer

Ultrasound of the abdomen

Question 3

What is the imaging finding of barium studies in Crohn's disease?

Accepted Answer

String sign

Answer

Apple core lesion

Answer

Bird beak sign

Answer

Coiled spring appearance

Question 4

The initial imaging investigation for suspected intestinal obstruction is?

Accepted Answer

X-ray abdomen

Answer

Ultrasound

Answer

CT scan

Answer

Barium study

Question 5

A 70-year-old male presents with a pulsatile abdominal mass. Which diagnostic study is most appropriate to confirm the presence of an abdominal aortic aneurysm?

Accepted Answer

Abdominal ultrasound

Answer

MRI

Answer

Plain X-ray

Answer

CT angiography

Question 6

A 50-year-old female presents with abdominal pain and jaundice. An MRI reveals multiple liver lesions with a 'target' appearance. What is the most likely diagnosis?

Accepted Answer

Liver metastases

Answer

Hepatic cysts

Answer

Hepatocellular carcinoma

Answer

Focal nodular hyperplasia

Question 7

Which imaging technique is essential for evaluating a suspected perforation of the gastrointestinal tract?

Accepted Answer

CT scan with IV contrast

Answer

Abdominal ultrasound

Answer

X-ray using oral contrast

Answer

MRI of the abdomen

Question 8

A patient with fever, back pain, and difficulty walking is diagnosed with a psoas abscess. Which imaging modality is the most effective for confirming the diagnosis?

Accepted Answer

CT scan

Answer

Ultrasound

Answer

X-ray

Answer

MRI

Question 9

What is the first-line imaging modality for suspected appendicitis in a young adult?

Accepted Answer

Ultrasound of the abdomen

Answer

X-ray abdomen

Answer

CT scan of the abdomen

Answer

MRI of the abdomen

Question 10

Which imaging modality is preferred for diagnosing placenta accreta in a 25-year-old pregnant woman at 20 weeks with a history of a previous cesarean delivery?

Accepted Answer

Transabdominal ultrasound

Answer

MRI

Answer

Transvaginal ultrasound

Answer

CT scan

Abdominal and Pelvic Radiology — MCQs

Abdominal and Pelvic Radiology — MCQs

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