Current issues of ACP Journal Club are published in Annals of Internal Medicine


Diagnosis

Biliary scintiscan had high sensitivity and specificity for predicting pathologic findings in the common bile duct

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ACP J Club. 2000 Sept-Oct;133:65. doi:10.7326/ACPJC-2000-133-2-065


Source Citation

Mathur SK, Soonawalla ZF, Shah SR, Goel M, Shikare S. Role of biliary scintiscan in predicting the need for cholangiography. Br J Surg. 2000 Feb;87:181-5. [PubMed ID: 10671924]


Abstract

Question

In patients with symptomatic gallstone disease, can biliary scintiscan predict the presence of pathologic findings in the common bile duct (CBD)?

Design

A blinded comparison of scintiscan and ultrasonography alone or combined with clinical or standard criteria (history of jaundice or acute pancreatitis, elevated serum bilirubin and alkaline phosphatase levels, and visualization of a stone or presence of dilated bile ducts on ultrasonography) and modified criteria (jaundice within the past 3 mo, elevated serum bilirubin and alkaline phosphatase levels, and visualization of a stone or presence of dilated bile ducts on ultrasonography).

Setting

A tertiary referral center in Bombay, India.

Patients

75 consecutive patients (mean age 46 y, 61% women) with symptomatic gallstone disease. Patients with acute cholecystitis, acute pancreatitis, or cholangitis were excluded.

Description of tests and diagnostic standard

Biliary scintigraphy was done using intravenous injection of 5 µCi 99mTc-radio-labeled mebrofenin with a recording at baseline and at 1 and 2 hours. Reading of recordings was blinded using predetermined criteria (standard and modified) for pathologic findings in the CBD. Positive ultrasonographic criteria were visualization of a CBD stone, presence of intrahepatic bile duct dilatation, or common hepatic duct or CBD size > 7 mm. The diagnostic standard was endoscopic or preoperative cholangiography; if calculi were found, endoscopic sphincterotomy or open surgical exploration of the CBD was done.

Main outcome measures

Sensitivity and specificity of features of biliary scintiscan, ultrasonography, and clinical criteria for predicting pathologic findings in the CBD.

Main results

Sensitivity and specificity for biliary scintiscan alone and combined with ultrasonography were high (Table). The sensitivity and specificity of other features or parameters are listed in the table.

Conclusion

Sensitivity and specificity for biliary scintiscan alone and combined with ultrasonography were high.

Source of funding: Not stated.

For correspondence: Dr. S.K. Mathur, 3rd Floor, Assistant Dean’s Bungalow, Dr. S.S. Rao Road, Bombay, 400 012, India. FAX 91-22-413-3435.


Table. Diagnostic findings and tests for predicting common bile duct (CBD) pathology in patients with symptomatic gallstone disease*

Diagnostic findings and tests Sensitivity Specificity +LR -LR
Abnormal findings on biliary scintigraphy 93% 94% 15 0.07
CBD > 9 mm with ultrasonography 63%† 100%† Infinity 0.4
CBD stone with ultrasonography 46%† 100%† Infinity 0.5
Abnormal bile duct with ultrasonography 67%† 96% 17 0.3
All standard criteria combined 89% 48%† 1.7 0.23
Modified standard criteria 89% 71%† 3 0.2
Ultrasonography and scintiscan 96% 98% 48 0.04

*Likelihood ratios defined in Glossary and calculated from data in article.
†Statistically different when compared with biliary scintigraphy (P ≤ 0.05)


Commentary

Cholangiography is considered the diagnostic standard in detecting CBD stones. Endoscopic retrograde and perioperative (intraoperative) cholangiography are 2 widely used methods. Both, however, are invasive and entail some risk. Finding a noninvasive or risk-free method of confirming or excluding CBD stones has always been frustrating. Mathur and colleagues have evaluated biliary scintigraphy and other noninvasive methods and criteria. Biliary scintigraphy was found to be superior to many of the noninvasive criteria used by the authors.

The best use of biliary scintigraphy to diagnose choledocolithiasis is probably in patients at high risk for cholangiography-related complications and with low probability for choledocolithiasis. In such patients, more information is needed to justify the risks and costs of cholangiography, especially if experts who can do the procedures are not readily available.

Potential criticisms of the study include a lack of clearly stated patient inclusion criteria, a lack of clearly stated criteria for biliary obstruction as seen on scintigraphy, and a methods section that requires several readings to be understood. Finally, all of the tests evaluated are highly operator dependent. Individual expertise should be considered when deciding to apply the results of this study.

The authors have re-explored and given new life to a widely available, safe, and relatively inexpensive tool. They are to be commended. Their results should spur others to further investigate the use of biliary scintigraphy.

William B. Silverman, MD
University of Iowa Hospitals and Clinics
Iowa City, Iowa, USA