Gallbladder Wall and Lumen Findings
| Finding | Recommendation |
|---|---|
| GB wall thickening (>3 mm), no symptoms | Ultrasound for characterization; clinical correlation for cholecystitis, hepatitis, CHF, portal hypertension |
| Gallstones (incidental, asymptomatic) | No follow-up; counsel patient; cholecystectomy only if symptomatic |
| Porcelain gallbladder (calcified wall) | Cholecystectomy referral — historically associated with malignancy; risk now debated but surgical referral remains standard |
| GB adenomyomatosis (focal/diffuse) | Ultrasound to confirm; no follow-up if classic appearance; surgery if symptomatic |
Gallbladder Polyps — SRU 2022 Guidelines
SRU 2022 replaced the prior ACR 2013 polyp thresholds. Risk factors for malignant polyps drive the approach: age >60, primary sclerosing cholangitis (PSC), familial adenomatous polyposis (FAP), symptomatic polyp, sessile morphology, or solitary polyp.
| Polyp Size | No Risk Factors | Risk Factors Present |
|---|---|---|
| <6 mm | No follow-up | US in 1 year |
| 6–9 mm | US in 6 months, then 1 year; if stable × 2 yr → discontinue | Cholecystectomy referral |
| ≥10 mm | Cholecystectomy referral | Cholecystectomy referral |
| Any size, sessile, growing >2 mm | Cholecystectomy referral | Cholecystectomy referral |
Cholesterol polyps are the most common gallbladder polyp type and are not premalignant — they appear as small, pedunculated, echogenic foci without acoustic shadow. True adenomas are much less common but have malignant potential, which is why size and morphology are the primary triage criteria.
Biliary Findings
| Finding | Recommendation |
|---|---|
| CBD dilation >6 mm (or >10 mm post-cholecystectomy), no obstructing cause found | MRCP or EUS to exclude choledocholithiasis or stricture; GI/surgery referral if etiology unclear |
| Intrahepatic biliary dilation without identifiable cause | MRCP; hepatobiliary referral |
| Bile duct wall thickening / periductal enhancement | MRCP with hepatobiliary contrast; IgG4/PSC workup; hepatobiliary surgery referral |
Post-cholecystectomy CBD dilation up to 10 mm can be a normal finding (compensatory dilation). The threshold for concern is >10 mm in asymptomatic post-cholecystectomy patients, or any new dilation with symptoms.
Why This Matters
Gallstones are found incidentally in 10–15% of the general population. The key message is that asymptomatic gallstones are managed expectantly — prophylactic cholecystectomy is not recommended. Gallbladder polyps require size-based follow-up because the malignancy risk of true adenomas scales with size; the SRU 2022 update raised the no-follow-up threshold for low-risk patients to <6 mm based on data showing near-zero malignancy risk below that size.
References
Sebastian S, Araujo C, Neitlich JD, Hooker CM, Silverman SG. Managing Incidental Findings on Abdominal and Pelvic CT and MRI, Part 4: White Paper of the ACR Incidental Findings Committee II on Gallbladder and Biliary Findings. J Am Coll Radiol. 2013;10(12):953–956.
Wiles R, Thoeni RF, Barbu ST, et al. Management and Follow-Up of Gallbladder Polyps. Radiology. 2022;305(2):277–289. [SRU 2022 Consensus]