Presurgical evaluation of the motor hand area with functional MR imaging in patients with tumors and dysplastic lesions.

PURPOSE: To test an optimized functional magnetic resonance (MR) imaging procedure to depict the motor hand representation area (HRA) in patients with epilepsy lesions near the central sulcus.

MATERIALS AND

METHODS

Fast low-angle shot MR imaging was performed with an oblique single-section imaging technique in eight control subjects (10 hemispheres) and six patients (12 hemispheres). Three series of five activation images (obtained while subjects performed repetitive finger-to-thumb opposition movements) and five rest images were acquired. Each hemisphere was studied in three adjacent sections. Difference maps (obtained with simple subtraction between activation and rest images) were compared with t-test maps.

RESULTS

In control subjects, the HRA was visible in 27 of 30 sections. Qualitatively, activation was seen better on t-test maps in 14 and on difference maps in four of these sections. In all patients, motor activation could be seen in the hemisphere that contained the lesion. This activation was considered normal in four patients. In two patients, the HRA was deformed. Functional MR imaging activation in the motor area was confirmed with Penfield stimulation in five patients.

CONCLUSION

Functional MR imaging findings in the preoperative assessment of dysplastic lesions around the central sulcus are the same as for tumors. t-test maps are superior to difference maps in the treatment of motor functional MR imaging data.