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Gallbladder and bile duct imaging
US is the first test for right upper quadrant pain: a mobile shadowing stone, a thick wall and a "sonographic Murphy sign" diagnose cholecystitis; a polyp does not move and does not shadow; then MRCP, EUS or ERCP is chosen by the risk of a duct stone.
Why it matters in the exam
A gallstone on US: echogenic, with posterior shadow and moving with position change. A contracted gallbladder full of stones gives the WES sign (wall-echo-shadow). Sludge — echogenic without shadow. A polyp — attached to the wall, immobile and without shadow; a polyp of 10 mm or more — cholecystectomy; 6–9 mm with a risk factor (age above 60, PSC, Indian ethnicity, sessile polyp) — consider cholecystectomy; otherwise follow-up. Acute cholecystitis (Tokyo 2018): thickened wall, pericholecystic fluid, distension, and a "sonographic Murphy sign" — pain when the probe presses on the gallbladder. If US is equivocal — HIDA. Gangrenous cholecystitis: asymmetric wall, membranes in the lumen, and sometimes no Murphy sign; emphysematous cholecystitis — gas in the wall, mainly in a diabetic man, and this is urgent.
Adenomyomatosis: fundal wall thickening with "comet-tail" artefact from crystals in Rokitansky-Aschoff sinuses — benign. Gallbladder carcinoma: older woman, large stones (above 3 cm), "porcelain" gallbladder, PSC and an anomalous pancreaticobiliary junction; it spreads early into the liver (segments IV and V). Xanthogranulomatous cholecystitis — mimics tumour, with hypoechoic nodules within the wall. Mirizzi syndrome: a stone lodged in the cystic duct or gallbladder neck presses on the common hepatic duct and causes jaundice.
Common bile duct stone (ASGE 2019): high risk (stone seen on US, cholangitis, or bilirubin above 4 with a dilated duct) — ERCP; intermediate risk — MRCP or EUS; low risk — cholecystectomy. Normal common duct diameter up to about 6 mm, a little wider in the elderly and after cholecystectomy. PSC — alternating strictures and dilatations ("beading"), associated with ulcerative colitis. Caroli disease — saccular dilatations of the intrahepatic ducts with a "central dot" (a portal branch within the duct). Hilar cholangiocarcinoma (Klatskin) — a stricture at the hilum with delayed enhancement. Rising bilirubin after cholecystectomy — bile leak or retained stone: HIDA for the leak, MRCP for the stone.
Key points
- US first in the right upper quadrant.
- Stone — shadow and movement; polyp — neither.
- Polyp 10 mm or more — resection.
- Duct stone: high risk ERCP, intermediate MRCP or EUS.
- Mirizzi — a stone in the neck compresses the hepatic duct.
Summary table
| Condition | US finding | Distinguishing feature | Next step |
|---|---|---|---|
| Gallstone | Echogenic, shadow, mobile | WES in a contracted gallbladder | Cholecystectomy if symptomatic |
| Polyp | Attached to the wall, immobile, no shadow | 10 mm or more — resection | Follow-up for a small polyp |
| Acute cholecystitis | Thick wall, fluid, sonographic Murphy | Gangrenous: membranes, asymmetric wall | HIDA if equivocal |
| Adenomyomatosis | Fundal thickening, comet tail | Benign | No treatment |
| Carcinoma | Mass or asymmetric thickening, liver invasion | Large stone, porcelain gallbladder | CT or MRI for staging |
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Sources
- Tokyo Guidelines 2018: Diagnostic Criteria and Severity Grading of Acute Cholecystitis, 2018 — Imaging findings
- ASGE Guideline on the Role of Endoscopy in the Evaluation and Management of Choledocholithiasis, 2019 — Risk stratification
- ESGAR/EAES/EFISDS/ESGE Joint Guideline on Gallbladder Polyps, 2022 — Size thresholds and follow-up
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.