Preoperative differentiation between T1a and ≥T1b gallbladder cancer: combined interpretation of high-resolution ultrasound and multidetector-row computed tomography.

OBJECTIVES: To determine the diagnostic value of combined interpretation of high-resolution ultrasound (HRUS) and multidetector-row computed tomography (MDCT) for preoperative differentiation between T1a and ≥T1b gallbladder (GB) cancer.
METHODS: Eighty-seven patients with pathologically confirmed GB cancers (T1a, n = 15; ≥T1b, n = 72), who preoperatively underwent both HRUS and MDCT, were included in this retrospective study. Two reviewers independently determined the T-stages of the GB cancers on HRUS and MDCT using a five-point confidence scale (5, definitely T1a; 1, definitely ≥T1b). For individual modality interpretation, the lesions with scores ≥4 were classified as T1a, and, for combined modality interpretation, the lesions with all scores ≥4 in both modalities were classified as T1a. The McNemar test was used to compare diagnostic performance.
RESULTS: The diagnostic accuracy of differentiation between T1a and ≥T1b GB cancer was higher using combined interpretation (90.8% and 88.5% for reviewers 1 and 2, respectively) than individual interpretation of HRUS (82.8% and 83.9%) or MDCT (74.7% and 82.8%) (P < 0.05, reviewer 1). Combined interpretations demonstrated 100% specificity for both reviewers, which was significantly higher than individual interpretations (P < 0.05, both reviewers).
CONCLUSIONS: Combined HRUS and MDCT interpretation may improve the diagnostic accuracy and specificity for differentiating between T1a and ≥T1b GB cancers. KEY POINTS: • Differentiating between T1a and ≥T1b gallbladder cancer can help surgical planning. • HRUS and MDCT are useful for local staging of gallbladder cancer. • HRUS and MDCT may be synergistic for T-staging of gallbladder cancer.