[Application of functional MR-images acquired at low field in planning of neurosurgical operation close to an eloquent brain area].

Aim Of The Study: Presentation of functional MRI performed at low magnetic field (1 Tesla) for planning microsurgical operation in a patient suffering from tumor close to an eloquent brain area.

Methods: Microsurgical removal navigated by frameless stereotaxy of an intrinsic tumor located in eloquent area is indicated if speech function is not damaged, i.e. exact localisation and relationship of the tumor and speech area can be defined. Before operation an optimized EPI based 2D sequence was applied to yield functional MR images. At the planning of the operation the paradigm used for the localization of the sensory language cortex contained passive listening to a text. Control investigations were performed one month postoperatively. A specific psychological test, as an additional investigation to estimate the accurate level of the sensory language function, was also conducted.

Results: Low resolution (matrix of 64x 64) functional MR images visualized sensory speech center and auditory cortex satisfactorily. The scans showed clearly that the Wernicke's region was situated just above the tumor (WHO grade II glioma), and this finding increased the safety of intraoperative localization and reduced the risk of morbidity. Control examinations revealed minimal decrease in sensory language function, however, it was not noticeable for either the patient or her surroundings.

Conclusion: Optimized functional MR imaging performed at low magnetic field can support planning of neurosurgical operations and reduce the morbidity of microsurgical interventions.