Helical CT of the local spread of carcinoma of the gallbladder: Evaluation according to the TNM system in patients who underwent surgical resection

OBJECTIVE. Our aim was to evaluate the performance of helical CT as an aid in the preoperative diagnosis of the spread of carcinomas of the gallbladder. MATERIALS AND METHODS. Two radiologists retrospectively reviewed both hardcopy and soft-copy (on a monitor with multiplanar reconstruction capability) versions of helical CT scans (3-mm collimation and 3-mm reconstruction) of 21 patients who had undergone surgical resection for carcinomas of the gallbladder. The local spread of the disease was evaluated according to the TNM system, and the results were correlated to the pathologic findings. Inter- and intraobserver differences were checked with kappa statistics. Results of the consensus interpretations were used to calculate sensitivity, specificity, and accuracy of helical CT. RESULTS. No significant inter- or intraobserver differences were found in any T category evaluation. The sensitivities of the hard-copy consensus interpretations in the diagnosis of T1, T2, T3, and T4 lesions were 33%, 64%, 80%, and 100%, respectively; specificities of hard-copy interpretations were 94%, 80%, 81%, and 95%, respectively. For soft-copy (monitor) consensus interpretations, the sensitivities for the diagnosis of T1, T2, T3, and T4 lesions were 33%, 73%, 80%, and 100%, respectively; the specificities of soft-copy interpretations were 94%, 80%, 88%, and 95%, respectively. Overall accuracy of the hard-copy interpretation was 83%; the overall accuracy of the soft-copy interpretation was not significantly different - 86%. CONCLUSION. Helical CT provided 83-86% accuracy in the diagnosis of the local extent of carcinomas of the gallbladder, showing acceptable sensitivity and specificity for the T2 and more advanced lesions but poor sensitivity for the T1 lesions. Use of a monitor with multiplanar reconstructions of the CT data did not significantly improve the diagnostic accuracy.