Abdominal and Pelvic Radiology Practice Questions

Q: Which is the best imaging modality for pheochromocytoma?

MRI abdomen. **Explanation:** The correct answer is **MRI abdomen**. In the diagnostic workup of pheochromocytoma, imaging is performed only after biochemical confirmation (elevated catecholamines/metanephrines). **Why MRI is the Best Modality:** MRI is considered the imaging modality of choice for localizing a pheochromocytoma due to its superior contrast resolution and ability to characterize tissue. A classic diagnostic feature is the **"Light Bulb Sign"**—marked hyperintensity on **T2-weighted images** due to high water content/vascularity. MRI is preferred over CT because it avoids ionizing radiation and does not require iodinated contrast, which theoretically carries a risk of triggering a hypertensive crisis (though this is less common with modern non-ionic contrast). **Analysis of Incorrect Options:** * **MIBG Scintigraphy (I-123/I-131):** While highly specific, it is a functional imaging technique used primarily for detecting **extra-adrenal (paragangliomas)**, metastatic, or recurrent disease, rather than initial localization. * **Somatostatin Scintigraphy:** Used for neuroendocrine tumors, but it is less sensitive than MIBG or PET for pheochromocytoma. * **PET DOPA:** This is the most sensitive functional imaging for certain genetic syndromes (like SDHB mutations), but it is not the first-line "best" modality for initial anatomical localization in a standard clinical setting. **High-Yield Clinical Pearls for NEET-PG:** * **Rule of 10s:** 10% bilateral, 10% malignant, 10% extra-adrenal, 10% pediatric, 10% familial. * **CT Appearance:** Pheochromocytomas show high attenuation (>20 HU) on non-contrast CT and delayed washout. * **Associated Syndromes:** MEN 2A/2B, von Hippel-Lindau (VHL), and NF-1. * **Management:** Always give **Alpha-blockers (Phenoxybenzamine)** before Beta-blockers to avoid unopposed alpha-receptor stimulation.

Q: Which imaging modality is best for detecting focal liver lesions?

MRI. **Explanation:** **MRI (Magnetic Resonance Imaging)** is the gold standard for detecting and characterizing focal liver lesions. Its superiority lies in its **high soft-tissue contrast resolution** and the ability to use **Hepatobiliary-specific contrast agents** (e.g., Gadoxetate disodium/Primovist). These agents are taken up by functional hepatocytes, allowing for the differentiation between lesions containing hepatocytes (like FNH) and those that do not (like metastases or HCC), significantly increasing sensitivity and specificity. **Why other options are incorrect:** * **CT (Computed Tomography):** While excellent for staging and rapid assessment, CT has lower soft-tissue contrast than MRI. It relies heavily on vascularity patterns (Triple-phase CT) but may miss small or isodense lesions that MRI can easily detect. * **USG (Ultrasonography):** This is the **initial screening modality** of choice due to its cost-effectiveness and lack of radiation. However, it is operator-dependent and has limited sensitivity for very small lesions or lesions in cirrhotic livers. * **PET Scan:** Primarily used for detecting metabolic activity (metastases or recurrence). It is not the primary modality for initial detection or anatomical characterization of primary liver lesions. **High-Yield Clinical Pearls for NEET-PG:** * **Best Initial Investigation:** USG. * **Best Modality for Characterization:** MRI. * **IOC for Hemangioma:** MRI (shows peripheral globular enhancement with "filling in"). * **IOC for HCC:** Triple-phase CT or Dynamic MRI (shows arterial enhancement with venous "washout"). * **Steatosis:** MRI (In-phase and Out-of-phase imaging) is the most sensitive for quantifying hepatic fat.

Q: What condition is characterized by a "bird beak" appearance?

Achalasia cardia. **Explanation:** **Achalasia Cardia (Correct Answer):** Achalasia is a primary esophageal motility disorder characterized by the failure of the Lower Esophageal Sphincter (LES) to relax and the absence of peristalsis in the distal esophagus. On a **Barium Swallow**, the classic finding is the **"Bird Beak" or "Rat Tail" appearance**. This represents a smooth, symmetric, tapered narrowing of the distal esophagus at the level of the gastroesophageal junction, with proximal esophageal dilatation (mega-esophagus). **Analysis of Incorrect Options:** * **Carcinoma Esophagus:** Typically presents with an **"Irregular Apple Core" appearance** or a "Shouldering effect." The narrowing is asymmetric, irregular, and has mucosal destruction, unlike the smooth tapering seen in Achalasia. * **Hiatus Hernia:** Characterized by the protrusion of the stomach through the diaphragmatic hiatus. Radiologically, it appears as a bulbous sac of barium above the diaphragm, often showing gastric mucosal folds. * **Diffuse Esophageal Spasm (DES):** Presents with uncoordinated, non-propulsive contractions. On Barium Swallow, this creates a **"Corkscrew Esophagus" or "Rosary Bead" appearance**. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Esophageal Manometry (shows incomplete LES relaxation and aperistalsis). * **Heller’s Myotomy:** The definitive surgical treatment. * **Chagas Disease:** A common secondary cause of Achalasia (caused by *Trypanosoma cruzi*). * **Sigmoid Esophagus:** The term used for the advanced, tortuous stage of esophageal dilatation in chronic Achalasia.

Q: Which is not a usual feature of Ulcerative colitis on barium enema?

Colovesical fistula. **Explanation:** The correct answer is **Colovesical fistula**. Ulcerative Colitis (UC) is a mucosal disease characterized by continuous inflammation limited to the mucosa and submucosa. Because it does not involve transmural inflammation, the formation of fistulae (such as colovesical or perianal fistulae) is extremely rare. Fistula formation is a hallmark of **Crohn’s Disease**, which involves transmural inflammation. **Analysis of Options:** * **Fine mucosal granularity (A):** This is the earliest radiological sign of UC on a double-contrast barium enema. It represents edema and hyperemia of the mucosa. * **Pseudopolyps (B):** These are islands of regenerating or normal mucosa surrounded by areas of extensive mucosal ulceration and depletion. They are a common feature of chronic UC. * **Lead pipe colon (C):** This refers to a featureless, narrowed, and shortened colon. It occurs in chronic stages due to the loss of haustral markings, longitudinal shortening, and muscular hypertrophy. **High-Yield Clinical Pearls for NEET-PG:** * **Earliest sign on Barium Enema:** Fine mucosal granularity. * **Collar-button ulcers:** Deep ulcers formed when the inflammatory process undermines the mucosa (also seen in UC). * **Backwash Ileitis:** Involvement of the terminal ileum in UC (occurs in ~10% of cases of pancolitis); unlike Crohn's, the ileocecal valve is usually patent/incompetent. * **Toxic Megacolon:** A life-threatening complication of UC where the transverse colon diameter exceeds **6 cm** on plain X-ray.

Q: All of the following are signs of Hydatid Cyst except?

Mercedes Benz sign. **Explanation:** The **Mercedes Benz sign** is the correct answer because it is a characteristic radiological feature of **cholelithiasis (gallstones)**, not hydatid disease. It represents the presence of triradiate, nitrogen-filled gas fissures within a gallstone, seen on a plain X-ray or CT scan. **Analysis of Hydatid Cyst Signs (Echinococcus granulosus):** * **Camalote sign (Water Lily sign):** This occurs when the endocyst ruptures, causing the germinal membrane to detach and float on the surface of the remaining cyst fluid. It is a classic sign seen on imaging (USG/CT/MRI). * **Floating membrane sign:** This is essentially the same mechanism as the Camalote sign, where detached membranes are seen undulating within the cyst cavity. * **Cartwheel (Ca wheel) appearance:** This occurs when multiple daughter cysts are arranged peripherally within the mother cyst, separated by internal septations (hydatid sand and matrix). This is characteristic of a **Type II hydatid cyst** (Gharbi classification). **High-Yield Clinical Pearls for NEET-PG:** * **Gharbi Classification:** Used to stage hydatid cysts (Type I: Pure fluid; Type II: Split wall/Membranes; Type III: Daughter cysts; Type IV: Solid/Heterogeneous; Type V: Calcified wall). * **Eggshell Calcification:** A common finding in the wall of a chronic hydatid cyst (Type V). * **Treatment:** The **PAIR** technique (Puncture, Aspiration, Injection of scolicidal agent, Re-aspiration) is a minimally invasive treatment option. * **Serology:** ELISA for Echinococcus IgG is the most common screening test.

Q: What is the characteristic appearance of a "Ca-wheel" on ultrasound?

Hydatid cyst. **Explanation:** The **"Cartwheel appearance"** (also known as the "spoke-wheel" or "honeycomb" appearance) is a classic radiological sign of a **Hydatid cyst** (caused by *Echinococcus granulosus*) on ultrasonography. This appearance occurs during the **WHO Stage CE2** (Active stage). It is produced by the presence of multiple **daughter cysts** separated by internal septations (representing the collapsed germinal membranes) within a larger mother cyst. **Why the other options are incorrect:** * **Intussusception:** Characteristically shows a **"Target sign"** or **"Donut sign"** on transverse sections and a **"Pseudokidney sign"** on longitudinal sections due to the telescoping of bowel loops. * **Hydatidiform mole:** Displays a characteristic **"Snowstorm appearance"** on ultrasound, caused by multiple hydropic villi appearing as tiny echogenic foci with interspersed cystic spaces. **High-Yield Clinical Pearls for NEET-PG:** 1. **Gharbi Classification:** Used for staging Hydatid cysts on USG. * **Type I:** Pure fluid collection (Anechoic). * **Type II:** Fluid collection with a split wall (**Water-lily sign** - detached endocyst). * **Type III:** Daughter cysts with septations (**Cartwheel/Honeycomb appearance**). * **Type IV:** Heterogeneous mass (Solid pattern). * **Type V:** Calcified wall (Inactive/Dead cyst). 2. **Treatment of Choice:** PAIR (Puncture, Aspiration, Injection, Re-aspiration) or surgical excision, usually covered with Albendazole. 3. **Serology:** ELISA is the most sensitive screening test for Hydatid disease.

Q: A 43-year-old woman presents with right upper quadrant abdominal pain and vomiting. She has had three children. The white blood cell count is 14.3x10^9/L and liver function tests are normal. What is the test of choice to establish the diagnosis in this patient?

Ultrasound. **Explanation:** The clinical presentation of right upper quadrant (RUQ) pain, vomiting, and leukocytosis in a middle-aged woman (fitting the "4F" profile: Female, Forty, Fertile, Fat) is highly suggestive of **Acute Cholecystitis** or symptomatic cholelithiasis. **Why Ultrasound is the Correct Answer:** Ultrasound (USG) is the **initial investigation of choice** for suspected gallbladder disease. It has high sensitivity (>90%) and specificity for detecting gallstones and signs of inflammation. Key sonographic findings of acute cholecystitis include gallbladder wall thickening (>3 mm), pericholecystic fluid, and the **Sonographic Murphy’s sign** (maximal tenderness over the gallbladder when compressed by the probe), which has a high positive predictive value. **Analysis of Incorrect Options:** * **A. CT Scan:** While useful for detecting complications (like perforation or gangrene) or alternative diagnoses, it is less sensitive than USG for detecting gallstones and involves ionizing radiation. * **C. HIDA Scan (Hepatobiliary Iminodiacetic Acid):** This is the **most sensitive (Gold Standard)** test for diagnosing acute cholecystitis (showing non-visualization of the gallbladder). However, it is not the *initial* test of choice because it is time-consuming, expensive, and involves nuclear medicine. * **D. MRI/MRCP:** These are excellent for visualizing the biliary tree (choledocholithiasis) but are not first-line due to cost and lack of immediate availability. **NEET-PG High-Yield Pearls:** * **Initial test for RUQ pain:** Ultrasound. * **Most sensitive/Gold Standard for Acute Cholecystitis:** HIDA Scan. * **Best test for Choledocholithiasis (CBD stones):** MRCP (Non-invasive) or ERCP (Invasive/Therapeutic). * **WES Triad on USG:** Wall-Echo-Shadow (indicates a gallbladder packed with stones).

Q: Cobra head deformity in the lower end of ureter is seen in which of the following conditions?

Ureterocele. **Explanation:** The **Cobra Head sign** (also known as the Adder head sign) is a classic radiological finding seen on an Intravenous Pyelogram (IVP) or Contrast CT, diagnostic of an **orthotopic ureterocele**. 1. **Why Ureterocele is correct:** A ureterocele is a congenital cystic dilatation of the distal-most intramural portion of the ureter. On a contrast study, the dilated ureter is filled with contrast (the "head"), which is surrounded by a thin, radiolucent halo representing the wall of the ureterocele and the bladder mucosa. This appearance mimics the hood of a cobra. 2. **Why other options are wrong:** * **Vesical diverticula:** These appear as contrast-filled outpouchings from the bladder wall (Hutch diverticulum), not as a filling defect within the bladder. * **Carcinoma of the urinary bladder:** This typically presents as an irregular, fixed filling defect. If it involves the ureteric orifice, it may cause hydroureter, but not the smooth, cystic "cobra head" appearance. * **Urethral stricture:** This is a narrowing of the urethra, best visualized on a Retrograde Urethrogram (RGU), and does not affect the distal ureteric morphology. **High-Yield Clinical Pearls for NEET-PG:** * **Simple (Orthotopic) Ureterocele:** Located at the normal vesicoureteric junction; usually seen in adults and produces the Cobra Head sign. * **Ectopic Ureterocele:** Located at the bladder neck or urethra; more common in children and often associated with a **duplicated collecting system** (Weigert-Meyer Law). * **Negative Cobra Head Sign:** If the radiolucent halo is thick or irregular, suspect a "pseudoureterocele," which can be caused by a stone impacted at the UVJ or a bladder tumor infiltrating the ureteric orifice.

Q: Radio-lucent renal stones are typically composed of which substance?

Uric acid. ### Explanation The radiopacity of a renal stone on a plain X-ray (KUB) depends on its effective atomic number. Stones containing elements with high atomic numbers, like Calcium, appear **radio-opaque** (white), while those composed of organic compounds without heavy metals appear **radiolucent** (black/invisible). **1. Why Uric Acid is Correct:** Uric acid stones are composed of carbon, nitrogen, oxygen, and hydrogen. These elements have low atomic numbers, making the stones **radiolucent** on conventional radiography. However, they are easily visualized as "hyperdense" on a Non-Contrast CT (NCCT) scan, which is the gold standard for diagnosis. **2. Analysis of Incorrect Options:** * **Calcium Phosphate (Option B):** These are the most radio-opaque stones due to the high atomic number of Calcium. * **Cysteine (Option A):** These stones contain sulfur atoms. While they are less opaque than calcium stones, they are described as **"ground-glass"** or **faintly radio-opaque**, not radiolucent. * **All of the above (Option D):** Incorrect, as the degree of opacity varies significantly between chemical compositions. **3. Clinical Pearls for NEET-PG:** * **Mnemonic for Radiolucent Stones (PU):** **P**urine (Uric acid) and **U**ndissolved medications (like Indinavir). * **Gold Standard Investigation:** NCCT KUB (detects all stones except Indinavir stones). * **Struvite Stones (Triple Phosphate):** Associated with Proteus infections; they are radio-opaque and often form **Staghorn calculi**. * **Management Tip:** Uric acid stones are unique because they can often be dissolved via **urinary alkalinization** (maintaining pH > 6.5).

Q: What is the diagnosis based on the ultrasound findings of an early pregnancy?

Complete mole. ***Complete mole*** - Shows the classic **"snowstorm"** or **"Swiss cheese"** appearance on ultrasound due to multiple **cystic spaces** representing hydropic villi. - **No fetal parts** or **fetal heart activity** are visualized, and **beta-hCG levels** are markedly elevated (>100,000 mIU/mL). *Partial mole* - Ultrasound shows **mixed echogenic pattern** with **focal cystic changes** and **fetal parts** may be present. - Associated with **triploid karyotype** (69,XXX or 69,XXY) and **lower beta-hCG levels** compared to complete mole. *Invasive mole* - **Cannot be diagnosed** by ultrasound alone as it appears similar to complete mole initially. - Diagnosis requires **histopathological evidence** of **myometrial invasion** and **persistently elevated beta-hCG** after evacuation. *Choriocarcinoma* - Ultrasound shows **heterogeneous mass** with **areas of hemorrhage** and **necrosis**, not the classic snowstorm pattern. - Develops after **any type of pregnancy** and shows **rapid metastatic spread** with **very high beta-hCG levels**.

Question 1

Which is the best imaging modality for pheochromocytoma?

Accepted Answer

MRI abdomen

Answer

MIBG Scintigraphy

Answer

Somatostatin Scintigraphy

Answer

PET DOPA

Question 2

Which imaging modality is best for detecting focal liver lesions?

Accepted Answer

MRI

Answer

CT

Answer

USG

Answer

PET scan

Question 3

What condition is characterized by a "bird beak" appearance?

Accepted Answer

Achalasia cardia

Answer

Carcinoma esophagus

Answer

Hiatus hernia

Answer

Diffuse esophageal spasm

Question 4

Which is not a usual feature of Ulcerative colitis on barium enema?

Accepted Answer

Colovesical fistula

Answer

Fine mucosal granularity

Answer

Pseudopolyps

Answer

Lead pipe colon

Question 5

All of the following are signs of Hydatid Cyst except?

Accepted Answer

Mercedes Benz sign

Answer

Camalote sign

Answer

Floating membrane sign

Answer

Ca wheel appearance

Question 6

What is the characteristic appearance of a "Ca-wheel" on ultrasound?

Accepted Answer

Hydatid cyst

Answer

Intussusception

Answer

Hydatidiform mole

Answer

All of the above

Question 7

A 43-year-old woman presents with right upper quadrant abdominal pain and vomiting. She has had three children. The white blood cell count is 14.3x10^9/L and liver function tests are normal. What is the test of choice to establish the diagnosis in this patient?

Accepted Answer

Ultrasound

Answer

Computerized axial tomography scan

Answer

Hydroxy iminodiacetic acid scan

Answer

Magnetic resonance imaging scan

Question 8

Cobra head deformity in the lower end of ureter is seen in which of the following conditions?

Accepted Answer

Ureterocele

Answer

Vesical diverticula

Answer

Carcinoma of the urinary bladder

Answer

Urethral stricture

Question 9

Radio-lucent renal stones are typically composed of which substance?

Accepted Answer

Uric acid

Answer

Cysteine

Answer

Calcium phosphate

Answer

All of the above

Question 10

What is the diagnosis based on the ultrasound findings of an early pregnancy?

Accepted Answer

Complete mole

Answer

Partial mole

Answer

Invasive mole

Answer

Choriocarcinoma

Abdominal and Pelvic Radiology — MCQs

Abdominal and Pelvic Radiology — MCQs

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