Source: DGNews  |  Posted 6 years ago

By Paula Moyer

HONOLULU, HI -- November 11, 2005 -- Endoscopic ultrasound is more accurate for diagnosing gallstones and other benign biliary disease than for malignant disease, according to research presented here at the American College of Gastroenterology (ACG).

However, better results might be obtained with endoscopic ultrasound for detecting malignancies when fine needle aspiration is used," said principal investigator Donald Garrow, MD, Clinical Instructor in the Division of Gastroenterology and Hepatology at the Medical University of South Carolina in Charleston, South Carolina, United States.

"The lack of radiation and lower procedure-related morbidity make endoscopic ultrasound an attractive option for diagnosing biliary disease," Dr. Garrow said during a presentation on November 2[^]nd[].

His research team studied this approach because endoscopic ultrasound gets high-resolution images of the bile duct and pancreas and yet avoids the risks of endoscopic retrograde cholangiopancreatography.

Although the sonographic approach might yield results that are comparable to magnetic resonance cholangiopancreatography, ultrasound is not use as widely. The investigators conducted a meta-analysis to assess the modality's performance in suspected biliary disease.

The investigators conducted a Medline search of studies published from 1988 to 2004, along with citation indexing. All studies were direct comparisons of endoscopic ultrasound to standard imaging modalities involving direct biliary opacification, such as endoscopic retrograde cholangiopancreatography or intraoperative or percutaneous cholangiography, and all had adequate clinical follow-up.

The investigators then adjusted for sample size, prevalence of disease, publication year, and study quality and used a random-effects model to estimate the pooled sensitivity and specificity. Two independent observers graded the study quality by whether it was blinded, patients were enrolled consecutively, the control used a single or composite standard, and direct cholangiography was used in more than or fewer than 90% of patients.

The investigators assessed the effects on diagnostic performance of each study's disease and sample size, clinical context, type of echoendoscope used, and publication year. They then analyzed the performance regarding overall presence of obstruction, diagnosis of choledocholithiasis, and whether obstruction was due to benign or malignant disease.

The investigators identified 31 eligible, non-overlapping studies that involved 3186 patients.

Pooled data showed that endoscopic ultrasound had a sensitivity of 87% and specificity of 92% for biliary obstruction, with an area-under-the-curve of ?0.92. The procedure had a sensitivity of 89% for choledocholithiasis and specificity of 95%. For malignancy, the sensitivity was 79%, and the specificity was 82%.

The investigators concluded that endoscopic ultrasound has excellent overall accuracy for diagnosing choledocholithiasis, but may have less accurate results for identifying malignancy.

However, they noted that these findings do not include the use of fine needle aspiration with endoscopic ultrasound. They suggested that the accuracy of the modality might increase when fine needle aspiration is used along with endoscopic ultrasound.

[Presentation title: Endoscopic Ultrasound: a Meta-Analysis of Test Performance in Suspected Biliary Disease. Abstract 65]