Dynamic gadolinium-enhanced MR imaging of recurrent inverted papilloma

To evaluate the usefulness of dynamic Gd-enhanced MR imaging in distinguishing recurrent inverted papilloma (IP) from postoperative changes. Ten patients with 13 surgical proved lesions were examined. T1-weighted (pre- and postcontrast), proton-density, and T2-weighted spin-echo images were evaluated. A total of nine dynamic FSE (fast spin-echo) images were obtained at 0, 5, 30, 60, 90, 120, 150, 180, and 300 seconds after bolus Gd-DTPA injection. Signal-time curves were obtained from dynamic scan. Reading of the T2-weighted images yielded a sensitivity of 75%, a specificity of 80%, and an accuracy of 77%. The contrast T1-weighted studies yielded a sensitivity of 63%, a specificity of 60%, and an accuracy of 67%. With a relative signal increase (RSI) of 2.0 or higher, a 60-second imaging time provided the sensitivity of 87% for the detection of recurrence and a specificity of 80%. There were significant differences in the RSI at 30, 60, 90, 120, 150, and 180 seconds (P < 0.01) between recurrent tumor and postoperative changes. Dynamic MR imaging can increase the diagnostic accuracy in the local recurrence of IP, and help differentiate recurrence and postoperative changes.