Diagnostic accuracy of multidetector-row computed tomography for common bile duct calculi: is it necessary to add non-contrast-enhanced images to contrast-enhanced images?

OBJECTIVE

To evaluate the diagnostic accuracy of 16-slice multidetector-row computed tomography (MDCT) for the detection of common bile duct (CBD) stones and to compare the diagnostic values between contrast-enhanced axial with multiplanar reformation (MPR) images and contrast-enhanced combined with non-contrast-enhanced axial images.

MATERIALS AND METHODS

Fifty-four patients with suspected CBD stones underwent MDCT and endoscopic retrograde cholangiopancreatography (ERCP). Two radiologists independently evaluated contrast-enhanced axial with MPR images for the presence of CBD stones. Two weeks later, they performed a second review of contrast-enhanced and non-contrast-enhanced axial images. The ERCP was used as the criterion standard to confirm the presence of CBD stones. The McNemar test and receiver operating characteristic curve analysis were used to assess the differences in accuracy for detecting CBD stones.

RESULTS

The ERCP identified bile duct stones in 27 patients and no stones in the other 27. Contrast-enhanced axial with MPR images had a sensitivity of 88.9%, specificity of 92.6%, and diagnostic accuracy of 90.7%. Contrast-enhanced combined with non-contrast-enhanced axial images had a sensitivity, specificity, and diagnostic accuracy of 88.9%. However, the difference between the 2 groups was not statistically significant. The areas under the receiver operating characteristic curve of the 2 groups were 0.929 and 0.905, respectively.

CONCLUSIONS

The MDCT provides high accuracy in diagnosis for CBD stones. Adding non-contrast-enhanced images to contrast-enhanced images did not improve diagnostic accuracy, and therefore, additional non-contrast-enhanced images are not necessary.