Clinical applications of functional MRI at 1.0 T: motor and language studies in healthy subjects and patients

In this article we describe clinical applications of functional MRI (fMRI) at 1.0 T. All experiments were performed on a commercially available 1.0-T system (Magnetom Impact Expert, Siemens AG, Erlangen, Germany) using a blood oxygen level-dependent (BOLD)-sensitive multi-slice EPI technique (TE 66 ms, 4 mm slice thickness, 210 mm field of view, 64 x 64 acquisition matrix). Different paradigms for localization of the motor cortex and for language lateralization were tested in healthy subjects and patients. Methodological considerations concerning the development of the paradigms are also described. In all healthy subjects, motor activation elicited BOLD signal changes in the sensorimotor cortex, permitting identification of primary motor and sensory cortical areas. Furthermore, focal activation of different cortical areas by a language task was possible in 6 of 10 subjects. Nineteen motor studies were performed in 18 patients with supratentorial lesions, in most cases prior to neurosurgical procedures. In 14 studies, fMRI results demonstrated the localization of the motor hand areas relative to the lesion. The results proved valuable for preoperative planning and contributed to therapeutical decisions. We conclude that functional MRI for clinically relevant applications, such as localization of motor and language function, is feasible even at a field strength of 1.0 T without dedicated equipment.