gms | German Medical Science

Objective: The identification of the central sulcus is crucial for any surgical approach. However, detection of the precentral gyrus on magnetic resonance imaging (MRI) is often difficult in perirolandic lesions due to perilesional edema and lesion expansion. Therefore, we analyzed the additional benefits of brain surface reformatted imaging (BRSI). After reformatting 3D-MR images, BRSI is able to visualize the entire central sulcus in one view.

Methods: For identifying the precentral gyrus on MRI, we used the following 6 landmarks: the conjunction of superior frontal gyrus and precentral gyrus in the shape of the capital letter L, the handknob, the thinner postcentral gyrus compared to the precentral gyrus, the pars bracket sign, the M-shaped inferior frontal gyrus merging with the precentral gyrus and the U-shaped connection of pre- and postcentral gyrus adjacent to the sylvian fissure. Conventional MRI and BRSI were evaluated by both an experienced neurosurgeon and neuroradiologist in 58 patients. The thus identified anatomical structures were compared to functional MRI (fMRI) and intraoperative electrophysiological findings.

Results: In the conventional MRI, a median of 2 landmarks (SD 1.5) on the lesion side could be identified compared to 5 landmarks (SD 1.2) in the BRSI (P<0.0001). Using conventional MRI, the precentral gyrus could be identified in 41/58 patients (71%). Evaluating the BRSI, the precentral region could be identified in 57 out of 58 patients (98%, P<0.0001). The number of landmarks for identification of the precentral gyrus was at least 3 out of 6 in conventional MRI versus 2 out of 6 signs in BRSI.

Conclusions: BRSI is easy to perform and it facilitates the identification of the precentral gyrus in perirolandic lesions with a high positive predictive value.