gms | German Medical Science

Objective: The aim of this study was to evaluate brain surface reformatted imaging (BSRI) in a neuronavigation system for localizing brain tumors.

Method: Eight patients suffering from perirolandic tumors were preoperatively studied with high resolution magnetic resonance imaging (MRI) and navigated transcranial magnetic stimulation (nTMS). In a second step, high resolution MRI were loaded in a neuronavigation software (Brainlab^®) which automatically transformed these data into BSR images. One experienced neuroradiologist, one experienced neurosurgeon and two residents determined hand representation areas ipsilateral to each tumor on conventional two-dimensional (2D) MR images and on BSR images. All results were compared to nTMS results. In addition, time needed for hand representation area determination on standard MR images and BSR images was recorded in every case, and observers judged wheter localization was difficult or easy.

Results: When compared to nTMS results, hand representation areas were correctly determined by BSRI in all but six cases (84.4%). However, on 2D-MR images only two respective incorrect localizations occured. In a subgroup analysis, experienced observers showed significantly more familiarity with BSRI than residents (93.8% vs 68.8% correct answers, p=0.001), with an equal error rate for 2D-MR images. Time required to define hand representation areas was significantly shorter using BSRI than using conventional 2D-MRI (mean 40.4 vs. 27.4 seconds, p=0.04). Judgement of difficulty in determining the precentral gyrus did not differ between 2D-MRI and BSRI.

Conclusions: BSRI enables fast and easy intraoperative localization of distinct brain regions, such as the precentral gyrus in tumor-associated distortions of brain anatomy. Thus, with BSRI a new and reliable intraoperative method for neuronavigation is now available.