Limitations of CT in the prediction of gallstone composition

Gallstones from 87 patients were harvested at cholecystectomy and selected for thin-section specimen CT and crystallographic analysis. A peripheral rim of density different from the center of the stone was noted in 32 (37%) of 87. The relative attenuations (HU) of the stone rim and stone core were recorded as the difference in attenuation from that of the distilled water bath. The correlation of these measurements with the percent cholesterol content in both the rim and core were poor (r = .57, 0.34, respectively). This paper reports the predictive ability of CT examined by defining predominantly cholesterol stones as having a relative core HV ≥ (62 of 87) and core cholesterol content ≥ 80% (59 of 87). Ct correctly predicted the composition as predominantly cholesterol or pigment in 68 of 87 (78%)