OBJECTIVETo review the preliminary clinical experience with high-field-strength intra-operative magnetic resonance imaging (iMRI) in the endoscopic chordoma operation with transsphenoidal or transoral approach.

METHODSFrom January 2009 to December 2010, 23 patients [range, 29 - 64 years, mean age (42 ± 3) years] of chordoma were operated with endoscopic transsphenoidal or transoral approach and examined intraoperatively with a movable 1.5 T iMRI magnet. Tumor size range was 2.0 - 5.7 cm, mean (3.5 ± 0.8) cm. A navigation system based on iMRI was used in 20 cases.

RESULTSiMRI scan were performed in each operation from 1 time to 5 times. Neuronavigation system were used in 20 operations and the data renewed in 12 cases by the information from iMRI. In 15 of 23 patients, iMRI had revealed residual lesions and resulted in 12 cases further treatment, eventually, 9 tumors were totally removed and 3 tumors were further removed. The ratio of total removal tumor was enhanced to 73.9% (17/23) from 34.8% (8/23). Among 15 cases of partial chordoma removal detected by scanning in operation, 9 were huge chordoma. The residual of huge chordoma detected by scanning in operation was 9/11, and other chordoma contributed to 6/12. There were no iMRI related safety issue or accident recorded in this study.

CONCLUSIONSHigh-field-strength iMRI provide high-quality images of tumor resection that allows intraoperative modification of the surgical strategy. Combined with the navigation system, iMRI is helpful to maximize the resection of the chordoma and benefit for the safety of endoscopic operation.