Body imaging spans GI, hepatobiliary, and genitourinary radiology — a high-yield, high-volume area in NEET SS and INI-SS. These free samples from the RadioQBank published set cover abdominal CT and MRI with full explanations, exam pearls, and references. Read each stem, commit to an answer, then check the reasoning.
Question 1 · Appendix · easy
Regarding the CT diagnosis of acute appendicitis, ALL of the following are recognised CT features EXCEPT:
- a. Appendix outer diameter >6 mm
- b. Periappendiceal fat stranding
- c. Appendicolith
- d. Free air in the right hemidiaphragm region
Answer: D. Free air under the right hemidiaphragm suggests a perforated viscus — however, a small subphrenic pneumoperitoneum is not a direct feature of acute appendicitis per se. Pneumoperitoneum does not occur in uncomplicated appendicitis, and even in perforated appendicitis, free air is seen in the right lower quadrant or perihepatic region, not specifically as a 'right subphrenic free air' in the typical teaching of appendicitis CT features. The recognised CT features are: appendix >6 mm, non-filling on CT, periappendiceal fat stranding, appendicolith, wall thickening, and (in perforation) pericecal fluid/abscess/extraluminal gas.
Exam pearl: Appendicitis CT triad = diameter >6 mm + periappendiceal stranding + non-opacification of lumen.
Radiographics 2007;27(4):1003–1021; AIIMS-MAMC-PGI Radiology Guide
Question 2 · Kidney · easy
A 50-year-old male undergoes CT abdomen showing a well-defined, homogeneous, fat-density mass (-20 to -120 HU) arising from the left kidney without enhancement or calcification. The most likely diagnosis and next step is:
- a. Angiomyolipoma — follow-up imaging
- b. Renal cell carcinoma — nephrectomy
- c. Liposarcoma — wide excision
- d. Lipoma — no further action
Answer: A. A well-defined renal mass with macroscopic fat (negative HU values on CT) is virtually diagnostic of angiomyolipoma (AML). AMLs are the most common benign renal neoplasm containing fat, and macroscopic fat detection on CT is considered pathognomonic (with rare exceptions of fat-containing RCC). For AMLs <4 cm with classic imaging features, active surveillance with follow-up imaging is appropriate. AMLs ≥4 cm or those with aneurysmal vascular components are at risk of hemorrhage and may warrant prophylactic embolization.
Exam pearl: Fat in renal mass = AML until proven otherwise. Exception: fat-containing RCC (very rare, look for calcification + fat). AML >4cm → risk of hemorrhage → consider embolization.
RadioGraphics 2017;37(3):803-818; AJR 2010;194(6):1470-1478
Question 3 · Oesophagus · moderate
A 50-year-old woman presents with progressive dysphagia. CT chest shows a posterior mediastinal mass at the level of T4-T6 with well-defined margins, no calcification, and intimate contact with the oesophagus. MRI shows a cystic lesion with T2 hyperintensity and T1 intermediate signal without enhancement. Endoscopy shows extrinsic compression with intact mucosa. What is the most likely diagnosis?
- a. Oesophageal leiomyoma
- b. Bronchogenic cyst
- c. Oesophageal duplication cyst
- d. Neurogenic tumour (schwannoma)
Answer: C. Oesophageal duplication cyst is a congenital foregut malformation sharing the same embryologic origin as the oesophagus. It typically occurs in the posterior mediastinum, most commonly on the right side, and is intimately associated with the oesophageal wall. MRI characteristics: T2 hyperintense, T1 variable (depends on protein content), no enhancement. Endoscopy shows extrinsic compression with intact mucosa. The wall may contain all oesophageal layers.
Exam pearl: T2 bright cystic lesion adherent to oesophageal wall = duplication cyst; no enhancement; CT cannot exclude haemorrhagic/proteinaceous content — MRI preferred.
Radiographics 2015; Grainger & Allison 7th ed
Question 4 · Spleen · moderate
A 48-year-old immunocompromised patient (post-renal transplant on tacrolimus) presents with fever and rigors. CT shows multiple 3–8 mm hypodense foci throughout the spleen, liver, and kidneys with a 'bull's-eye' pattern (central hypodense with surrounding rim) on post-contrast CT. No lymphadenopathy. What is the most likely diagnosis?
- a. Splenic lymphoma with miliary deposits
- b. Disseminated candidiasis (hepatosplenic candidiasis)
- c. Miliary tuberculosis
- d. Peliosis hepatis with splenic involvement
Answer: B. Hepatosplenic candidiasis (disseminated candidiasis) classically occurs in immunocompromised patients (especially post-transplant, haematological malignancy) and produces the characteristic 'bull's-eye' or 'target' pattern on CT — a central hypodense focus (fungal nidus) with a surrounding ring (inflammatory reaction) in the liver and spleen. Multiple organ involvement (liver, spleen, kidney) is typical. The temporal association with immunosuppression and multi-organ 'bull's-eye' lesions is diagnostic.
Exam pearl: Immunocompromised + bull's-eye liver/spleen lesions = hepatosplenic candidiasis; MRI = central dark T1/T2 core with bright ring = target sign.
Radiographics 2011;31:543; AJR 1994;162:341
Question 5 · Adrenal · hard
A 61-year-old woman with known breast carcinoma undergoes FDG PET-CT. An adrenal mass shows maximum SUV of 8.2. Unenhanced CT density is 32 HU. Contralateral adrenal and liver appear normal. What is the most appropriate next step to guide systemic therapy decisions?
- a. Adrenal washout CT in 3 months
- b. Laparoscopic adrenalectomy
- c. CT-guided adrenal biopsy after phaeochromocytoma exclusion
- d. Accept as adrenal metastasis and commence systemic therapy
Answer: C. FDG avid adrenal mass (SUV 8.2) with unenhanced HU of 32 in a patient with known breast cancer is highly suspicious for adrenal metastasis, but histological confirmation is mandatory before changing systemic therapy, especially if it is the only site of apparent progression. Adrenal biopsy is safe and accurate, but biochemical exclusion of phaeochromocytoma must precede any needle intervention to prevent hypertensive crisis. Once phaeochromocytoma is excluded, CT-guided core biopsy provides tissue for receptor profiling and confirms the nature of the metastasis.
Exam pearl: Always exclude phaeochromocytoma biochemically before adrenal biopsy — needle puncture of an unsuspected phaeochromocytoma can cause fatal hypertensive crisis.
ACR Adrenal Incidentaloma 2022; Radiographics 2020;40(4):1079
Question 6 · Adrenal · hard
A 44-year-old man with hypertension and headaches has a 3 cm right adrenal mass and elevated 24-hour urine normetanephrines. He has a germline SDHB mutation. Which imaging modality has the highest sensitivity for detecting additional lesions in SDHB-associated paraganglioma/phaeochromocytoma?
- a. 123I-MIBG scintigraphy
- b. 68Ga-DOTATATE PET-CT
- c. FDG PET-CT
- d. CT chest/abdomen/pelvis
Answer: B. SDHB-mutated paragangliomas/phaeochromocytomas overexpress somatostatin receptors (SSTR2), making 68Ga-DOTATATE PET-CT the most sensitive modality for detection and staging. DOTATATE PET-CT has >90% sensitivity for SDH-mutated tumours, detects multi-focal and metastatic disease not seen on MIBG or CT, and guides treatment selection (PRRT eligibility). SDHB mutations carry the highest risk of malignancy (30–40%) among hereditary phaeochromocytoma/paraganglioma syndromes.
Exam pearl: SDHB mutation = highest malignant risk (30–40%) among hereditary PPGL syndromes. Best imaging: 68Ga-DOTATATE PET-CT (SSTR overexpression). DOTATATE also guides PRRT eligibility.
Radiographics 2018;38(4):1174; AJR 2020;214(2):405