← Issue №11/ week of Sep 13, 2026/Endoscopy

Greener Choices in Biliary Imaging: A Prospective Carbon Footprint Comparison of EUS versus MRCP for Intermediate-Likelihood Choledocholithiasis.

From GI Signals issue №11: what this paper found, what it changes, and where it sits against the current standard of care, reviewed by Simon Mathews, MD.

Endoscopy prospective cohort · n=108 · Sep 8, 2026 · Clin Transl Gastro · IF 3.4

Greener Choices in Biliary Imaging: A Prospective Carbon Footprint Comparison of EUS versus MRCP for Intermediate-Likelihood Choledocholithiasis.

New evidencecholedocholithiasisEUShealth services
Clinical takeawayFor intermediate-likelihood CBD stones, EUS and MRCP remain diagnostically equivalent per guidelines. On carbon-intensive grids, EUS reduces per-procedure emissions 4.2-fold compared to MRCP (4.53 vs 18.90 kg CO2e), adding environmental impact to the accuracy, safety, and cost decision. On low-carbon grids, this advantage narrows and may not apply. Where available and suitable, consider EUS accounting for local grid carbon intensity, patient preference, and local expertise.
What it foundEUS generated 4.53 kg CO2e per procedure versus MRCP 18.90 kg CO2e (4.2-fold difference); MRCP's continuous cryocooler standby was the largest single contributor to emissions (23.4%).
ContextConfirms diagnostic equivalence of EUS and MRCP per guidelines. Introduces environmental footprint as a new decision discriminator; this is the first direct carbon comparison of these two biliary imaging modalities. Environmental advantage is greatest on carbon-intensive grids.
Refinessuggested applicable standard· American Society for Gastrointestinal Endoscopy (ASGE), "ASGE guideline on the role of endoscopy in the evaluation and management of choledocholithiasis" (Buxbaum JL et al., Gastrointest Endosc 2019;89(6):1075-1105), 2019

Decision at stakeWhich confirmatory imaging modality to use for intermediate-likelihood choledocholithiasis

No single passage of this standard matched the paper closely enough to quote, so none is shown. The standard is cited above.

Our full summary of this standard

Risk-stratify suspected choledocholithiasis (high >50%, intermediate 10-50%, low <10% probability). HIGH-risk criteria, any of which should directly prompt ERCP: (1) CBD stone on ultrasound or cross-sectional imaging; (2) ascending cholangitis; (3) total bilirubin >4 mg/dL AND dilated CBD (>6 mm in adults with gallbladder in situ, >8 mm after cholecystectomy). Gallstone pancreatitis was deliberately REMOVED as a high-risk criterion in the 2019 revision. INTERMEDIATE risk (abnormal liver biochemical tests, age >55 y, or bile-duct dilation on imaging): the panel suggests confirmation with either EUS or MRCP (conditional recommendation, low-quality evidence; choice by patient preference, local expertise, availability), laparoscopic intraoperative cholangiography (IOC) or intraoperative US are equally sanctioned alternatives. LOW risk: cholecystectomy with or without IOC/intraoperative US if indicated for symptomatic cholelithiasis; no ERCP and no mandatory advanced biliary imaging. In gallstone pancreatitis WITHOUT cholangitis or biliary obstruction/choledocholithiasis, the panel recommends AGAINST urgent (<48 h) ERCP (strong recommendation, low-quality evidence). Same-admission cholecystectomy is recommended for patients with MILD gallstone pancreatitis (consensus, PONCHO-based); ERCP with prophylactic sphincterotomy should not be used as an alternative to cholecystectomy unless surgery is absolutely contraindicated (e.g., recurrent pancreatitis in end-stage liver disease). For large bile-duct stones, the panel suggests endoscopic sphincterotomy followed by large-balloon dilation (ES-LBD) rather than sphincterotomy alone (conditional, moderate); for large AND difficult stones, it suggests intraductal therapy (cholangioscopy-guided EHL or laser lithotripsy) or conventional therapy with papillary dilation, chosen by local expertise, cost, and patient/physician preference (conditional, very low). Timing versus cholecystectomy: pre- or postoperative ERCP or laparoscopic bile-duct clearance for patients at high risk or with positive IOC, depending on local surgical and endoscopic expertise (consensus).

American Society for Gastrointestinal Endoscopy (ASGE), "ASGE guideline on the role of endoscopy in the evaluation and management of choledocholithiasis" (Buxbaum JL et al., Gastrointest Endosc 2019;89(6):1075-1105), 2019 · reviewed 2026-07-19 ↗
Rughwani H … Reddy DN · Clinical and Translational Gastroenterology · IF 3.4 · PubMed ↗Permalink
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