# Predictive Value of Transabdominal Ultrasonography in Detecting Extrahepatic Bile Duct Obstructive Lesions Compared with Endoscopic Retrograde Cholangiopancreatography

## TL;DR

This study shows that transabdominal ultrasonography is a reliable, non-invasive method for detecting bile duct blockages, with results comparable to the more invasive ERCP procedure.

## Contribution

The study provides empirical evidence of the high diagnostic accuracy of TAUS compared to ERCP for bile duct obstructive lesions.

## Key findings

- TAUS and ERCP showed strong agreement in detecting bile duct obstructions (Cohen’s Kappa = 0.748).
- TAUS demonstrated high sensitivity and positive predictive value for bile duct stones and pancreatic cancer.
- TAUS is a safe, non-invasive alternative with minimal risk for diagnosing bile duct obstruction causes.

## Abstract

Transabdominal ultrasonography (TAUS) remains the initial imaging modality in diagnosis of bile duct obstructive lesions. The purpose of this study was to investigate the predictive value of TAUS in detecting bile duct obstructive lesions in comparison with endoscopic retrograde cholangiopancreatography (ERCP) as the standard method.

This retrospective descriptive study analyzed the electronic records of the patients diagnosed with obstructive jaundice from April 2017 to November 2022 at Alsafwa Consultative Medical Center in Almukalla City, Hadhramout, Yemen. All patients involved were diagnosed by TAUS and the diagnosis was confirmed by ERCP. A comparison of the diagnoses was performed.

TAUS and ERCP demonstrated high compatibility in bile duct obstructive lesions, with substantial agreement in detecting cholangiocarcinoma, bile duct stricture, stones, pancreatic cancer, and ampulla of Vater mass (compatibility ranging from 71.4% to 100%, Cohen’s Kappa = 0.748, p < 0.001). Pearson correlation indicated strong agreement between the two methods (r=0.856). TAUS showed high sensitivity, and positive predictive value (PPV), particularly for bile duct stones (99.4% sensitivity, 86.7% PPV), and pancreatic carcinoma (94.3% sensitivity, 82.5% PPV), with significant effectiveness in identifying other conditions like bile duct stricture (42.6% sensitivity, 88.5% PPV) and cholangiocarcinoma (70.6% sensitivity, 100% PPV). (p<0.001). Overall, TAUS and ERCP displayed excellent compatibility across various diagnoses, with near-perfect agreement in determining the causes in the ampulla of Vater and bile duct (Kappa= 0.899, p<0.001)

TAUS is a reliable and highly valuable imaging modality for detecting and determining the cause and level of bile duct obstruction in patients with obstructive jaundice which offers a non-invasive approach, radiation free, with minimal risk of serious complications.