Abdominal and Pelvic Radiology Practice Questions

Q: A previously healthy 61-year-old woman presents with a 3-week history of altered bowel habit and rectal bleeding. She refuses to undergo colonoscopy. Which of the following is the next best investigation?

CT colonography. **Explanation:** The clinical presentation of altered bowel habits and rectal bleeding in a 61-year-old is highly suspicious for **Colorectal Carcinoma (CRC)**. While colonoscopy is the gold standard for diagnosis and biopsy, **CT Colonography (CTC)**, also known as "Virtual Colonoscopy," is the preferred alternative when a patient refuses or cannot tolerate conventional colonoscopy. **Why CT Colonography is the Correct Choice:** * **High Sensitivity:** CTC uses thin-slice CT data and 3D reconstruction to detect polyps and masses >10mm with sensitivity comparable to optical colonoscopy. * **Non-Invasive:** It does not require sedation and carries a much lower risk of perforation compared to traditional colonoscopy. * **Staging Capability:** Unlike barium studies, CTC can simultaneously evaluate the bowel wall, extraluminal extension, and distant metastases (TNM staging). **Analysis of Incorrect Options:** * **B. CT Abdomen and Pelvis:** A standard contrast-enhanced CT without specific colonic distension (air/CO2) has poor sensitivity for detecting small mucosal lesions or early-stage tumors. * **C. Barium Enema:** Historically used, but now largely replaced by CTC. It has lower sensitivity for small polyps and cannot provide information regarding extraluminal spread or lymphadenopathy. * **D. Barium Meal Follow-Through:** This is used to evaluate the **small intestine** (e.g., Crohn’s disease). It is not an appropriate investigation for suspected rectal or colonic pathology. **High-Yield Clinical Pearls for NEET-PG:** * **Apple Core Sign:** The classic radiological appearance of annular constricting colorectal carcinoma on barium studies. * **Screening:** In average-risk individuals, screening for CRC should begin at age 45. * **Contraindication:** CTC is contraindicated in patients with acute diverticulitis or recent bowel surgery due to the risk of perforation during insufflation.

Q: A 40-year-old male complains of recurrent urinary tract infections. An X-ray KUB shows a radio-opaque shadow. What is the most likely diagnosis?

Ureteric pathology. ### Explanation **Correct Option: A. Ureteric pathology** The presence of a **radio-opaque shadow** on an X-ray KUB (Kidney, Ureter, Bladder) in a patient with recurrent urinary tract infections (UTIs) most commonly signifies a **urinary calculus**. Since the ureter lies within the anatomical field of a KUB film, a stone lodged in the ureter (ureterolithiasis) will appear as an opacity. Recurrent UTIs are a frequent complication of urolithiasis due to urinary stasis and nidus formation for bacteria. **Why other options are incorrect:** * **B. Prostate pathology:** While prostatic calculi exist, they are usually small, multiple, and located behind the symphysis pubis. Most common prostate pathologies (like BPH or Cancer) are soft-tissue changes not visible as distinct radio-opaque shadows on a standard X-ray. * **C. Testicular pathology:** The testes are located in the scrotum, which is generally outside the primary field of a standard KUB. Testicular pathologies (like tumors or torsion) are evaluated via Ultrasound/Doppler, not X-ray. * **D. Stricture urethra:** A stricture is a narrowing of the urethral lumen. It is a soft-tissue abnormality and is **radiolucent**. It requires a Retrograde Urethrogram (RGU) for visualization, not a plain X-ray. **High-Yield Clinical Pearls for NEET-PG:** * **90% of urinary stones** are radio-opaque (Calcium oxalate > Calcium phosphate > Magnesium ammonium phosphate/Struvite). * **Pure Uric Acid, Xanthine, and Indinavir stones** are radiolucent (not seen on X-ray). * **Phleboliths** (calcified pelvic veins) are the most common mimics of ureteric stones; they often have a "lucent center." * **Investigation of Choice:** Non-contrast CT (NCCT) KUB is the gold standard for detecting all types of urinary stones.

Q: What do the arrows on an abdominal radiograph indicate?

Small bowel obstruction. ***Small bowel obstruction*** - The arrows typically point to **dilated small bowel loops** with prominent **valvulae conniventes** (complete circular folds crossing the entire bowel width). - Classic radiographic features include **air-fluid levels** on upright films and **central distribution** of dilated loops, indicating mechanical obstruction. *Crohn's disease* - Plain radiographs are usually **normal** in early disease or show non-specific findings like mild bowel wall thickening. - **Skip lesions** and **terminal ileal involvement** are better demonstrated on **CT** or **contrast studies**, not plain X-rays. *Ulcerative colitis* - Plain abdominal X-rays typically show **colonic dilatation** rather than small bowel changes, especially in toxic megacolon. - The disease primarily affects the **colon** starting from the rectum, with **loss of haustral markings** ("lead pipe" appearance) on barium enema. *Ileocaecal Tuberculosis* - Plain radiographs are often **non-specific** and may appear normal in early stages. - Diagnosis requires **contrast studies** or **CT** to demonstrate **ileocaecal thickening**, **strictures**, and **lymphadenopathy**.

Q: A 45-year-old patient is found to have an incidental adrenal mass on routine imaging. The lesion is shown above. Which MRI sequence is best suited for characterizing this adrenal lesion?

Chemical shift imaging MRI. ***Chemical shift imaging MRI*** - **In-phase/out-of-phase imaging** is the gold standard for characterizing **adrenal adenomas** by detecting **intracellular lipid content**. - **Signal drop** on out-of-phase images compared to in-phase images strongly supports a lipid-rich adrenal adenoma, confirming the presence of **microscopic fat**. *T2W* - Provides good **anatomical detail** but lacks specificity for differentiating **benign adenomas** from **malignant lesions**. - Both adenomas and metastases can appear **hyperintense** on T2-weighted images, making differentiation difficult. *DWI* - Useful for detecting **restricted diffusion** in malignant lesions but has **limited specificity** for adrenal adenomas. - **ADC values** can overlap between benign and malignant adrenal masses, reducing diagnostic accuracy. *STIR* - Excellent for **fluid detection** and **edema** but suppresses **fat signal**, making it unsuitable for lipid-rich adenoma characterization. - Cannot differentiate between **lipid-poor adenomas** and **malignant masses** due to similar signal characteristics.

Q: The "string sign" on imaging is suggestive of which of the following conditions?

Hypertrophic Pyloric Stenosis (HPS). ### Explanation **Correct Answer: B. Hypertrophic Pyloric Stenosis (HPS)** The **"String Sign"** is a classic radiological finding in Hypertrophic Pyloric Stenosis (HPS). It is seen on a Barium swallow study when the contrast passes through a severely narrowed and elongated pyloric canal. The hypertrophy of the circular muscle of the pylorus causes luminal constriction, leaving only a thin "string" of contrast visible. **Analysis of Incorrect Options:** * **A. Toxic Megacolon:** Characterized by massive colonic dilation (usually >6 cm) and loss of haustral markings. The classic sign is a "distended, air-filled colon" on a plain X-ray, not a string sign. * **C. Ulcerative Colitis:** Chronic inflammation leads to the loss of haustral folds and shortening of the colon, resulting in the **"Lead Pipe"** appearance. (Note: A "String Sign" can be seen in **Crohn’s Disease** due to terminal ileum narrowing, but it is not a feature of Ulcerative Colitis). * **D. Irritable Bowel Syndrome (IBS):** This is a functional disorder; imaging is typically normal and does not show structural narrowing or the string sign. **High-Yield Clinical Pearls for NEET-PG:** * **HPS Presentation:** Typically occurs in first-born males (3–6 weeks old) with **non-bilious, projectile vomiting**. * **Physical Exam:** A palpable, firm, mobile mass in the epigastrium known as the **"Olive sign."** * **Metabolic Profile:** Hypochloremic, hypokalemic metabolic alkalosis (due to loss of HCl from vomiting). * **Other HPS Signs:** * **Beak Sign:** Contrast entering the proximal end of the narrowed canal. * **Shoulder Sign:** Bulging of the pyloric muscle into the antrum. * **Double Track Sign:** Two thin streaks of barium separated by a radiolucent mucosal fold. * **Investigation of Choice:** Ultrasound (Criteria: Pyloric muscle thickness >3-4 mm or length >14-16 mm).

Q: A middle-aged patient presents with a complaint of right hypochondrial pain. An X-ray shows an elevated right hemidiaphragm. Which of the following is NOT a possible diagnosis?

Acute cholecystitis. **Explanation:** The elevation of a hemidiaphragm on a chest or abdominal X-ray is typically caused by either **phrenic nerve palsy**, **intrathoracic volume loss** (e.g., collapse), or **intra-abdominal pathology** that exerts upward pressure or causes reactive irritation of the diaphragmatic muscle. **Why Acute Cholecystitis is the Correct Answer:** In **Acute Cholecystitis**, the inflammation is localized to the gallbladder, which is situated on the inferior surface of the liver, well away from the diaphragmatic pleura. While it causes significant right hypochondrial pain and tenderness (Murphy’s sign), it typically does not involve the superior surface of the liver or the subphrenic space. Therefore, it does not cause the mass effect or diaphragmatic irritation required to elevate the hemidiaphragm. **Analysis of Incorrect Options:** * **Subphrenic Abscess (Option A):** An accumulation of infected fluid between the liver and the diaphragm directly pushes the diaphragm upward and causes reactive paralysis/splinting. * **Pyogenic & Amoebic Liver Abscesses (Options C & D):** Large abscesses, especially those located in the superior segments of the right lobe of the liver, cause hepatomegaly and localized inflammatory changes that frequently result in an elevated right hemidiaphragm and occasionally a reactive pleural effusion. **NEET-PG High-Yield Pearls:** * **Eventration of Diaphragm:** A congenital condition where the diaphragm is thin/weak (muscular aplasia), leading to permanent elevation. * **Phrenic Nerve Palsy:** Most common cause of a newly elevated hemidiaphragm; confirmed by the **Sniff Test** (paradoxical upward movement of the paralyzed side during inspiration under fluoroscopy). * **Amoebic Liver Abscess:** Classically presents with "anchovy sauce" pus; elevation of the right hemidiaphragm is a classic radiological sign.

Q: Thumb printing on imaging is characteristic of which of the following conditions?

Ischemic colitis. **Explanation:** **Thumbprinting** is a classic radiologic sign seen on plain abdominal X-rays or barium studies. It represents **submucosal edema and hemorrhage**, which causes the bowel wall to bulge into the lumen, creating indentations that resemble thumbprints. **Why Ischemic Colitis is Correct:** In **Ischemic Colitis**, sudden hypoperfusion leads to capillary leakage and intramural hemorrhage. This most commonly occurs at "watershed areas" like the splenic flexure (Griffith’s point) or the rectosigmoid junction (Sudeck’s point). The resulting focal submucosal thickening produces the characteristic thumbprinting appearance. **Analysis of Incorrect Options:** * **Crohn's Disease:** Characterized by transmural inflammation, "skip lesions," and a "string sign" (due to strictures) or "cobblestone appearance" (due to deep longitudinal ulcers). * **Ulcerative Colitis:** Typically presents with a "lead pipe" appearance in chronic stages due to the loss of haustral markings and shortening of the colon. * **Lymphogranuloma venereum (LGV):** A sexually transmitted infection that primarily causes proctocolitis and strictures in the rectum, but does not typically present with acute submucosal edema/thumbprinting. **NEET-PG High-Yield Pearls:** 1. **Most common site for Ischemic Colitis:** Splenic flexure (Griffith’s point). 2. **Other causes of Thumbprinting:** While ischemic colitis is the classic answer, it can also be seen in severe ulcerative colitis (toxic megacolon), pseudomembranous colitis, and bowel wall hematomas. 3. **Clinical Presentation:** Typically an elderly patient with sudden onset left-sided abdominal pain followed by bloody diarrhea (hematochezia).

Question 1

What is the investigation of choice for retroperitoneal soft tissue sarcomas?

Accepted Answer

CT Scan

Answer

MRI

Answer

USG

Answer

PET scan

Question 2

A previously healthy 61-year-old woman presents with a 3-week history of altered bowel habit and rectal bleeding. She refuses to undergo colonoscopy. Which of the following is the next best investigation?

Accepted Answer

CT colonography

Answer

CT abdomen and pelvis

Answer

Barium enema

Answer

Barium meal follow-through

Question 3

A 40-year-old male complains of recurrent urinary tract infections. An X-ray KUB shows a radio-opaque shadow. What is the most likely diagnosis?

Accepted Answer

Ureteric pathology

Answer

Prostate pathology

Answer

Testicular pathology

Answer

Stricture urethra

Question 4

A contrast enema in this 82-year-old patient with diabetes mellitus who had undergone a total hip replacement 10 years previously demonstrates passage of contrast into the urinary bladder. What is the most likely underlying diagnosis responsible for this finding?

Accepted Answer

Diverticular disease

Answer

Crohn disease

Answer

Colon cancer

Answer

Prior pelvic radiation

Question 5

What do the arrows on an abdominal radiograph indicate?

Accepted Answer

Small bowel obstruction

Answer

Crohn's disease

Answer

Ulcerative colitis

Answer

Ileocaecal Tuberculosis

Question 6

All are true about the radiological features of intestinal obstruction except?

Accepted Answer

Volvulus and mesenteric ischemia have characteristic signs on abdominal films.

Answer

The small intestines are said to be dilated if the loops of bowel have a diameter of > 3 cm.

Answer

The large bowel is said to be dilated if it is > 5 cm for distal bowel and > 9 cm for proximal bowel.

Answer

The absence of air-fluid levels on plain supine radiographs does not rule out the presence of an obstruction.

Question 7

A 45-year-old patient is found to have an incidental adrenal mass on routine imaging. The lesion is shown above. Which MRI sequence is best suited for characterizing this adrenal lesion?

Accepted Answer

Chemical shift imaging MRI

Answer

STIR

Answer

T2W

Answer

DWI

Question 8

The "string sign" on imaging is suggestive of which of the following conditions?

Accepted Answer

Hypertrophic Pyloric Stenosis (HPS)

Answer

Toxic Megacolon

Answer

Ulcerative Colitis

Answer

Irritable Bowel Syndrome (IBS)

Question 9

A middle-aged patient presents with a complaint of right hypochondrial pain. An X-ray shows an elevated right hemidiaphragm. Which of the following is NOT a possible diagnosis?

Accepted Answer

Acute cholecystitis

Answer

Subphrenic abscess

Answer

Pyogenic liver abscess

Answer

Amoebic liver abscess in the right lobe

Question 10

Thumb printing on imaging is characteristic of which of the following conditions?

Accepted Answer

Ischemic colitis

Answer

Crohn's disease

Answer

Lymphogranuloma venereum (LGV)

Answer

Ulcerative colitis

Abdominal and Pelvic Radiology — MCQs

Abdominal and Pelvic Radiology — MCQs

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