FUNCTIONAL MRI - PRIMARY MOTOR CORTEX LOCALIZATION IN PATIENTS WITH BRAIN-TUMORS

Purpose: Our goal was (a) to test the ability of functional MRI (fMRI) to localize the hand primary motor cortex in patients with brain neop lasms using a conventional scanner and (b) to compare within the same subject the location and morphology of the activated motor areas in th e affected hemisphere with the contralateral ones. Method: Seventeen r ight-handed patients with frontoparietal intra- and extraaxial tumors were studied. Hand motor performance ranged from normal to slight impa irment of finger dexterity. The fMRI study was based on a series of FL ASH images. Two or three contiguous slices parallel to the bicommissur al plane were acquired through the level of frontoparietal cortex. Eac h patient was requested to perform with each hand a finger-tapping tas k or a simpler repetitive flexion-extension of the last four fingers. Pseudo-color activation maps were then calculated by a Z-score method and superimposed on high resolution images. Results: Five patients wer e excluded because of gross motion artifacts. In all other patients, a reas of significant signal increase were detected on the precentral gy rus. They had a spot-like appearance, and no substantial side-to-side differences in shape or extension could be observed. In the presence o f severe compression of the gyri, a displacement of the activated area s in the affected hemisphere with respect to the contralateral ones wa s noticeable. Conclusion: fMRI localization of the primary motor area using a conventional scanner can be obtained also in patients with bra in tumors, although with a lower success rate than in normal volunteer studies, mainly because of subject compliance problems. Areas of sign ificantly increased signal are detectable even in cortex where normal anatomical patterns are lost.