Gadoxetic acid-enhanced MRI for T-staging of gallbladder carcinoma: Emphasis on liver invasion

Objective: To evaluate the diagnostic performance of gadoxetic acid-enhanced MRI with an emphasis on the usefulness of the hepatobiliary phase (HBP) in T-staging of gallbladder carcinoma. Methods: 66 patients with surgically confirmed gallbladder carcinoma underwent MRI. Two radiologists independently reviewed two sets of gadoxetic acid-enhanced MRI without and with the HBP. Local tumour spread was evaluated according to T-staging, and the results were compared with pathological findings. The diagnostic performance of two image sets to differentiate each T-stage was compared. Results: The sensitivities of MRI with the HBP to differentiate T1 vs $T2 lesions, #T2 vs $T3 lesions and #T3 vs T4 lesions were 96.3%, 85.7% and 100% for Observer 1 and 92.6%, 95.2% and 100% for Observer 2, respectively (p,0.0001). By adding the HBP, the sensitivities to differentiate #T2 vs $T3 lesions were increased from 66.7% to 85.7% for Observer 1 and from 81.0% to 95.2% for Observer 2, although there was no ignificant difference (p.0.05). The overall accuracies for T-staging were increased from 80.3% to 86.4% for Observer 1, a statistically significant degree (p50.046), and from 83.8% to 87.9% for Observer 2 (p.0.05). The k-value for the two observers indicated excellent agreement. Conclusion: Gadoxetic acid-enhanced MRI provided acceptable diagnostic performance for T-staging of gallbladder carcinoma. Addition of the HBP aids in the detection of liver invasion. Advances in knowledge: In the T-staging of gallbladder carcinoma, gadoxetic acid-enhanced MRI with the HBP may enhance detection of liver invasion.