Preoperative renal tumor evaluation by three-dimensional magnetic resonance imaging: Staging and detection of multifocality

Objectives To evaluate, retrospectively, the staging accuracy of three-dimensional magnetic resonance imaging (3D-MRI) in our institution as a prelude to a prospective comparison of 3D-MRI and 3D computed tomography (CT) for preoperative planning of partial nephrectomy. In recent years, the use of 3D-CT for preoperative evaluation and surgical planning in patients undergoing nephron-sparing surgery has gained considerable popularity. Methods The images of 26 consecutive patients evaluated by 3D-MRI as part of the preoperative imaging studies for renal tumor were evaluated retrospectively and compared with the surgical pathologic findings to evaluate the ability of 3D-MRI to predict tumor multifocality, tumor stage, collecting system invasion, and venous invasion. Results 3D-MRI accurately predicted tumor multifocality in 1 of 2 cases. Imaging identified five of seven multifocal lesions. Two subcentimeter lesions were missed. Preoperative staging was correct in 29 of 30 lesions (97% accuracy). One T3b tumor was incorrectly staged as T2. Venous invasion was identified in 2 of 3 cases (67% sensitivity), but no false-positive results were seen. 3D-MRI had 100% sensitivity and 88% specificity in the prediction of collecting system invasion. Conclusions The staging accuracy of 3D-MRI appears to be quite good. Given the accuracy of this technique, along with the popularity of 3D imaging before renal surgery, these results provide the impetus for a future study directly comparing 3D-CT with 3D-MRI in the capacity of surgical preoperative planning.