Abdominal and Pelvic Radiology — MCQs

Abdominal and Pelvic Radiology Indian Medical PG Practice Questions and MCQs

Question 41: Three-dimensional localization of a tooth in the maxillary sinus is best achieved with which imaging combination?

A. Intraoral periapical radiograph + maxillary occlusal radiograph
B. Lateral cephalogram + maxillary occlusal radiograph
C. Orthopantomogram + maxillary occlusal radiograph
D. Water's view radiograph + maxillary occlusal radiograph (Correct Answer)

Explanation: **Explanation:** To achieve **three-dimensional localization** of an object (like an ectopic tooth) using conventional radiography, one must apply the principle of **orthogonal imaging**. This requires two views taken at right angles (90 degrees) to one another to provide spatial data in the sagittal, coronal, and axial planes. **Why Option D is correct:** * **Water’s View (Occipitomental view):** This is the gold standard plain film for visualizing the maxillary sinuses. It provides a clear **coronal/frontal** perspective, showing the mediolateral and superoinferior position of the tooth without interference from the petrous temporal bones. * **Maxillary Occlusal Radiograph:** This view provides an **axial (top-down)** perspective. * **Combination:** Together, they allow the clinician to determine if the tooth is anterior/posterior (Occlusal) and medial/lateral or superior/inferior (Water’s), effectively localizing it in 3D space. **Analysis of Incorrect Options:** * **Option A:** IOPA films have a limited field of view and often fail to capture the superior extent of the maxillary sinus. * **Option B:** A Lateral Cephalogram provides a sagittal view but suffers from significant superimposition of the right and left maxillary structures, making side-specific localization difficult. * **Option C:** An OPG (Orthopantomogram) is a 2D tomographic slice. While it shows the whole jaw, it provides poor depth perception and is often distorted in the maxillary region. **NEET-PG High-Yield Pearls:** * **Water’s View:** Best for Maxillary Sinuses; the patient’s head is tilted back at 37° to the film. * **Caldwell’s View:** Best for Frontal and Ethmoid sinuses. * **SLOB Rule (Same Lingual, Opposite Buccal):** The primary radiographic principle used for localizing objects using two different horizontal tube angulations. * **Gold Standard:** While this question focuses on plain films, **CBCT (Cone Beam Computed Tomography)** is the modern gold standard for 3D localization in maxillofacial imaging.

Question 42: A 10-year-old female presented with recurrent attacks of cholangitis. CECT was done; what is the most likely diagnosis based on CECT findings?

A. Type 1 choledochal cyst
B. Type 3 choledochal cyst
C. Type 4 choledochal cyst
D. Type 5 choledochal cyst (Correct Answer)

Explanation: ***Type 5 choledochal cyst*** - Recurrent **cholangitis** in a child with **multiple intrahepatic biliary dilatations** on CECT is pathognomonic of **Type 5 choledochal cyst (Caroli disease)**. - CECT shows the characteristic **central dot sign** representing portal vein branches within dilated intrahepatic bile ducts, confirming the diagnosis. *Type 1 choledochal cyst* - Presents as **fusiform dilatation of the common bile duct** with normal intrahepatic ducts on imaging. - Would not show **multiple intrahepatic cystic dilatations** as seen in this case with recurrent cholangitis. *Type 3 choledochal cyst* - Involves **choledochocele** - cystic dilatation of the **distal common bile duct** within the duodenal wall. - CECT would show a **small cystic lesion** in the pancreaticoduodenal region, not intrahepatic changes. *Type 4 choledochal cyst* - Features **both extrahepatic and intrahepatic** bile duct dilatations with **fusiform CBD dilatation**. - Differs from Type 5 as it includes **extrahepatic involvement** and lacks the pure intrahepatic cystic pattern seen here.

Question 43: In cholangiography, how does a common bile duct (CBD) stone typically appear?

A. Meniscus sign (Correct Answer)
B. Cutoff sign
C. Slight flow of dye from the sides
D. Ability to absorb water

Explanation: **Explanation:** In cholangiography (ERCP, MRCP, or T-tube cholangiography), a **Common Bile Duct (CBD) stone** typically appears as a **filling defect** within the contrast-filled duct. Because stones are usually rounded or oval, the contrast medium flows around the upper convexity of the stone, creating a characteristic concave, crescentic border known as the **Meniscus sign**. This sign is highly suggestive of an intraluminal filling defect like a calculus. **Analysis of Options:** * **A. Meniscus sign (Correct):** The rounded superior margin of a stone creates a "crescent" or "meniscus" appearance of the contrast, similar to the meniscus of fluid in a graduated cylinder. * **B. Cutoff sign:** This refers to an abrupt, complete termination of the contrast column. While a stone can cause an obstruction, a "rat-tail" or "abrupt" cutoff is more characteristic of **malignancy** (e.g., Cholangiocarcinoma or Pancreatic head cancer). * **C. Slight flow of dye from the sides:** While contrast may trickle past a non-obstructing stone, this is a descriptive finding rather than a named radiological sign. * **D. Ability to absorb water:** Gallstones are typically composed of cholesterol, bile pigments, and calcium salts; they do not "absorb" water or contrast in a way that defines their radiological appearance. **Clinical Pearls for NEET-PG:** * **Gold Standard:** MRCP is the non-invasive gold standard for diagnosing CBD stones (choledocholithiasis), showing them as signal voids on T2-weighted images. * **ERCP:** Remains the gold standard for **therapeutic** intervention (sphincterotomy and stone extraction). * **Differential Diagnosis:** A "Shouldering effect" or "Rat-tail appearance" on cholangiography should immediately raise suspicion for **malignant strictures**.

Question 44: What is the investigation of choice for posterior urethral valve?

A. Micturition cystourethrogram (Correct Answer)
B. Retrograde urethrography
C. Ultrasound
D. Intravenous pyelogram (IVP)

Explanation: **Explanation:** **Posterior Urethral Valve (PUV)** is the most common cause of lower urinary tract obstruction in male infants. It involves obstructing mucosal folds in the prostatic urethra. **1. Why Micturition Cystourethrogram (MCUG/VCUG) is the Correct Answer:** MCUG is the **gold standard** and investigation of choice because it captures the anatomy during the voiding phase. The classic findings on MCUG include: * **Dilatation and elongation of the posterior urethra** (proximal to the valve). * A sharp transition to a narrow caliber in the anterior urethra. * Secondary changes like a "Christmas tree" bladder (trabeculations) and **vesicoureteral reflux (VUR)**, which is seen in approximately 50% of cases. **2. Why Other Options are Incorrect:** * **Retrograde Urethrography (RGU):** This is primarily used to evaluate anterior urethral strictures in adults. It involves injecting dye against the flow of urine, which may fail to demonstrate the valve mechanism or the dilated posterior urethra effectively. * **Ultrasound:** While often the initial screening tool (showing bilateral hydronephrosis or a thick-walled bladder), it cannot definitively diagnose the valve or its exact location. The "keyhole sign" on prenatal USG is suggestive but not confirmatory. * **Intravenous Pyelogram (IVP):** This is rarely used in neonates due to immature renal concentrating ability and poor visualization. It does not provide the necessary detail of the urethral anatomy. **Clinical Pearls for NEET-PG:** * **Initial Management:** Catheterization (using a small feeding tube) to decompress the bladder. * **Definitive Treatment:** Endoscopic primary valve ablation (Fulguration). * **Keyhole Sign:** Refers to the dilated posterior urethra and thick-walled bladder seen on ultrasound. * **Most common cause** of chronic kidney disease (CKD) in children.

Question 45: A liver lesion showing multiseptate cystic areas with eggshell or mural calcifications on CT scan is suggestive of?

A. Hemangioma
B. Hydatid Cyst (Correct Answer)
C. Amebic Liver abscess
D. Hepatocellular Carcinoma (HCC)

Explanation: **Explanation:** The correct answer is **Hydatid Cyst** (caused by *Echinococcus granulosus*). The CT findings described—multiseptate cystic areas and mural calcification—are classic hallmarks of this parasitic infection. **Why Hydatid Cyst is correct:** * **Multiseptate/Daughter Cysts:** As the mother cyst matures, internal budding produces daughter cysts, giving a "cyst-within-a-cyst" or "spoke-wheel" appearance. * **Eggshell Calcification:** Calcification occurs in the ectocyst (pericyst). While it can be seen in about 20-30% of cases, curvilinear or "eggshell" calcification is highly suggestive of a Hydatid cyst. * **Water Lily Sign:** Detachment of the endocyst membrane results in the "floating membrane" appearance on imaging. **Why other options are incorrect:** * **Hemangioma:** The most common benign liver tumor. On CT, it shows **peripheral globular enhancement** with centripetal fill-in (delayed enhancement). It is typically solid, not multiloculated cystic. * **Amebic Liver Abscess:** Usually presents as a single, poorly defined hypodense collection (often in the right lobe) with a "shaggy" wall. It lacks internal daughter cysts and eggshell calcification. * **Hepatocellular Carcinoma (HCC):** A solid tumor characterized by **arterial phase enhancement** and **venous phase washout**. While it can undergo central necrosis, it does not present as a multiseptate calcified cyst. **High-Yield Clinical Pearls for NEET-PG:** * **WHO Classification:** Uses the **Gharbi Classification** for ultrasound staging. * **Serology:** ELISA for IgG antibodies is the screening test of choice. * **Treatment:** PAIR (Puncture, Aspiration, Injection, Re-aspiration) is used for certain stages, always covered by **Albendazole** to prevent anaphylaxis from spillage.

Question 46: A patient presents with recent loss of hypertension control and a creatinine of 4.2 mg/dL. Renal ultrasound shows size discrepancy in the kidneys and no signs of obstruction. What should be the next investigation?

A. Intravenous pyelography (IVP)
B. Magnetic resonance angiography (MRA)
C. Retrograde pyelography
D. Ultrasound Doppler (Correct Answer)

Explanation: **Explanation:** The clinical presentation of sudden loss of blood pressure control (suggestive of renovascular hypertension) combined with a significant size discrepancy between the kidneys and elevated creatinine (4.2 mg/dL) strongly points toward **Renal Artery Stenosis (RAS)** leading to ischemic nephropathy. **Why Ultrasound Doppler is correct:** In a patient with advanced renal failure (Creatinine > 3.0 mg/dL), the choice of imaging is dictated by safety. **Color Doppler Ultrasound** is the initial investigation of choice because it is non-invasive, does not require contrast, and carries no risk of nephrotoxicity. It can evaluate peak systolic velocity (PSV) and the resistive index to diagnose stenosis. **Why other options are incorrect:** * **Intravenous Pyelography (IVP):** This is contraindicated in patients with elevated creatinine due to the high risk of contrast-induced nephropathy (CIN). Furthermore, it is a poor modality for evaluating vascular structures. * **Magnetic Resonance Angiography (MRA):** While excellent for visualizing renal arteries, gadolinium-based contrast agents are contraindicated in patients with a GFR < 30 mL/min (Creatinine 4.2 mg/dL) due to the risk of **Nephrogenic Systemic Fibrosis (NSF)**. * **Retrograde Pyelography:** This is used to visualize the collecting system and ureters when there is an obstruction. Since the ultrasound already ruled out obstruction (hydronephrosis), this procedure is not indicated. **Clinical Pearls for NEET-PG:** * **Gold Standard for RAS:** Digital Subtraction Angiography (DSA). * **Screening Test for RAS:** Renal Doppler. * **Size Discrepancy:** A difference of >1.5 cm in renal longitudinal length is a significant indicator of unilateral renal artery stenosis. * **ACE Inhibitors:** These are contraindicated in bilateral renal artery stenosis as they can precipitate acute renal failure.

Question 47: A lobulated mass extending into the gastric bubble with rat tail tapering of the lower esophagus in a barium swallow is indicative of which condition?

A. Diffuse esophageal spasm
B. Hypertrophic pyloric stenosis
C. Esophageal cancer (Ca esophagus) (Correct Answer)
D. Gastroesophageal reflux

Explanation: ### Explanation The correct answer is **Esophageal cancer (Ca esophagus)**. **1. Why it is correct:** The description provided is a classic radiological presentation of a malignant growth at the gastroesophageal (GE) junction. * **Rat-tail tapering:** This refers to an irregular, eccentric, and abrupt narrowing of the esophageal lumen caused by an infiltrating circumferential tumor. This is in contrast to the "bird-beak" appearance seen in Achalasia, which is smooth and symmetrical. * **Lobulated mass in the gastric bubble:** This indicates that the esophageal tumor has extended inferiorly into the cardia or fundus of the stomach, creating a filling defect within the normal air-filled gastric bubble on a barium swallow. **2. Why the other options are incorrect:** * **Diffuse esophageal spasm:** Characterized by a **"Corkscrew esophagus"** or "Rosary bead" appearance due to tertiary non-peristaltic contractions. It does not present with a mass or rat-tail tapering. * **Hypertrophic pyloric stenosis:** This is a pediatric condition affecting the gastric outlet (pylorus), not the esophagus. Classic signs include the **"String sign"** or "Double track sign" on barium studies. * **Gastroesophageal reflux (GERD):** Chronic GERD may lead to peptic strictures, which typically show smooth, tapered narrowing, or Barrett’s esophagus, but not a lobulated mass or irregular rat-tail tapering. **3. NEET-PG Clinical Pearls:** * **Bird-beak appearance:** Achalasia Cardia (Smooth tapering). * **Rat-tail/Shouldering effect:** Esophageal Carcinoma (Irregular tapering). * **Corkscrew esophagus:** Diffuse Esophageal Spasm. * **Bread crumb appearance:** Seen in a barium swallow in cases of esophageal candidiasis. * **Most common histological type:** Squamous cell carcinoma (worldwide), though Adenocarcinoma is rising in the West due to Barrett’s esophagus.

Question 48: The finding of a single umbilical artery on ultrasound is an indicator of what in the fetus?

A. Considerably increased incidence of major malformations (Correct Answer)
B. Occurs in 10% of newborns
C. Insignificant
D. Equally common in newborns of diabetic and nondiabetic mothers

Explanation: **Explanation:** The umbilical cord normally contains **two arteries and one vein**. A **Single Umbilical Artery (SUA)**, also known as a 2-vessel cord, occurs due to either primary agenesis of one artery or the secondary atrophy of a previously present vessel. **1. Why Option A is Correct:** SUA is a significant sonographic marker because it is associated with a **considerably increased incidence of major congenital malformations** (found in approximately 20–30% of affected fetuses). The most common associations include **genitourinary anomalies** (e.g., renal agenesis), cardiovascular defects, and gastrointestinal issues. It is also linked to chromosomal trisomies (especially Trisomy 18 and 13) and Intrauterine Growth Restriction (IUGR). **2. Why Other Options are Incorrect:** * **Option B:** SUA is not found in 10% of newborns; its incidence is much lower, occurring in approximately **0.5% to 1%** of singleton pregnancies and about 5% of twin pregnancies. * **Option C:** It is far from insignificant. While an "isolated" SUA in the absence of other markers often has a good prognosis, its discovery necessitates a detailed Level II anomaly scan and fetal echocardiography. * **Option D:** SUA is significantly **more common** (3–4 times higher incidence) in infants of **diabetic mothers** compared to non-diabetic mothers. **High-Yield Clinical Pearls for NEET-PG:** * **Best View:** SUA is best visualized in the **perivesical view** (axial section of the fetal pelvis) using color Doppler, showing only one artery flanking the fetal bladder. * **Most Common Association:** Renal anomalies are the most frequent systemic association. * **Management:** If SUA is detected, perform a thorough structural survey. If isolated, serial growth scans are recommended due to the risk of IUGR.

Question 49: Micturating cystourethrogram is not used in which of the following conditions?

A. Renal tumours (Correct Answer)
B. Hydronephrosis
C. Urinary obstruction
D. Recurrent UTI

Explanation: **Explanation:** A **Micturating Cystourethrogram (MCUG)**, also known as a Voiding Cystourethrogram (VCUG), is a dynamic fluoroscopic study used primarily to evaluate the **lower urinary tract** (bladder and urethra) and the presence of **vesicoureteral reflux (VUR)**. **Why Renal Tumours is the Correct Answer:** Renal tumours (such as Wilms' tumour or Renal Cell Carcinoma) are pathologies of the **renal parenchyma**. The gold standard for evaluating renal masses is **Contrast-Enhanced CT (CECT)** or MRI. Since MCUG involves filling the bladder via a catheter to visualize the outflow tract, it provides no diagnostic information regarding the solid tissue of the kidney. **Analysis of Incorrect Options:** * **Hydronephrosis:** MCUG is a first-line investigation in pediatric hydronephrosis to rule out VUR or Posterior Urethral Valves (PUV) as the underlying cause. * **Urinary Obstruction:** It is the definitive test for diagnosing infravesical obstructions, most notably **Posterior Urethral Valves (PUV)** in male infants, showing a dilated posterior urethra. * **Recurrent UTI:** In children, recurrent UTIs necessitate an MCUG to check for VUR, which predisposes the kidneys to scarring and pyelonephritis. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard:** MCUG is the gold standard for diagnosing **Vesicoureteral Reflux (VUR)** and **Posterior Urethral Valves (PUV)**. * **Timing:** It should ideally be performed 4–6 weeks after a UTI has resolved to avoid false positives due to bladder inflammation. * **Key Finding:** A "Christmas tree bladder" on MCUG/cystography suggests a **neurogenic bladder**. * **Prophylaxis:** Antibiotic coverage is mandatory before performing the procedure to prevent iatrogenic sepsis.

Question 50: Which of the following imaging techniques is NOT used for the evaluation of uterine anomalies?

A. Hysterosalpingography (HSG)
B. MRI guided HSG
C. CT guided HSG (Correct Answer)
D. Ultrasonography (USG)

Explanation: **Explanation:** The evaluation of uterine anomalies (Müllerian duct anomalies) focuses on visualizing the external contour of the uterus and the internal shape of the endometrial cavity. **Why CT guided HSG is the correct answer:** Computed Tomography (CT) is **not** a standard modality for evaluating uterine anomalies. It provides poor soft-tissue contrast for the myometrium compared to MRI and involves significant ionizing radiation to the pelvis, which is contraindicated in women of reproductive age seeking fertility evaluation. There is no clinical procedure termed "CT guided HSG" used for this purpose. **Analysis of other options:** * **Hysterosalpingography (HSG):** Traditionally the first-line test for assessing the uterine cavity and tubal patency. While it cannot visualize the external uterine contour (making it difficult to differentiate between a septate and bicornuate uterus), it remains a core diagnostic tool. * **MRI (and MRI guided/enhanced techniques):** MRI is the **Gold Standard** for diagnosing uterine anomalies. It provides excellent soft-tissue characterization, allowing for clear visualization of both the internal cavity and the external fundal contour without radiation. * **Ultrasonography (USG):** 2D-USG is often the initial screening tool. **3D-USG** is highly accurate and is now considered comparable to MRI for classifying Müllerian duct anomalies. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard for Uterine Anomalies:** MRI. * **Best Initial Investigation:** USG (specifically 3D-USG if available). * **Differentiating Septate vs. Bicornuate:** Look at the fundal contour. A fundal cleft >1 cm indicates a bicornuate uterus; a flat or convex fundus indicates a septate uterus. * **Most common anomaly associated with renal agenesis:** Didelphys uterus. * **Most common Müllerian anomaly:** Septate uterus (also associated with the highest rate of infertility/miscarriage).

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Renal and Urinary Tract Imaging

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Adrenal Imaging

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Male Pelvic Imaging

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