Chest X-Ray Signs
Air bronchogram: Air-filled bronchus visible through consolidated lung. Sign of consolidation (pneumonia).
Silhouette sign: Loss of normal border between two structures of similar density. Right heart border lost = right middle lobe collapse.
Bat wing appearance: Bilateral perihilar infiltrates. Classic for pulmonary edema.
Kerley B lines: Horizontal lines at lung bases. Sign of interstitial pulmonary edema.
Abdominal Radiology
- Riglers sign: Both sides of bowel wall visible = pneumoperitoneum
- Coffee bean sign: Sigmoid volvulus
- Hausser sign: Multiple air-fluid levels = small bowel obstruction
MRI Sequences
T1-weighted: Fat = bright, water = dark. Good for anatomy.
T2-weighted: Water = bright, fat = bright. Good for pathology.
DWI: Restricted diffusion = bright (acute stroke, abscess).
Key CT Findings
Hyperdense = acute hemorrhage. Hypodense = infarct, cyst, edema.
References & further reading
Every clinical claim in this article is anchored to a primary source. Click through to verify, and use the same habit in your revision.
Revision history
- 19 September 2026 — Initial publication
Frequently asked questions
How is radiology tested in UPSC CMS?
As image-based questions showing X-rays, CT or MRI images. Questions ask you to identify the modality, the finding, or the diagnosis. Chest X-rays are the most common.
What are the most common X-ray signs to know?
Air bronchogram, silhouette sign, Kerley B lines, eggshell calcification, tram track appearance, honeycombing, bat wing appearance, reverse pulmonary vascularity.
Do I need to know MRI sequences?
Know the basics: T1 (fat bright), T2 (water bright), FLAIR (suppresses CSF), DWI (acute stroke). These appear in questions about CNS imaging.
Related reading
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