Use of functional MRI to guide decisions in a clinical stroke trial

Background and Purpose - An investigational trial examined safety and efficacy of targeted subthreshold cortical stimulation in patients with chronic stroke. The anatomical location for the target, hand motor area, varies across subjects, and so was localized with functional MRI ( fMRI). This report describes the experience of incorporating standardized fMRI into a multisite stroke trial. Methods - At 3 enrollment centers, patients moved (0.25 Hz) the affected hand during fMRI. Hand motor function was localized at a fourth center guiding intervention for those randomized to stimulation. Results - The fMRI results were available within 24 hours. Across 12 patients, activation site variability was substantial ( 12, 23, and 11 mm in x, y, and z directions), exceeding stimulating electrode dimensions. Conclusion - Use of fMRI to guide decision-making in a clinical stroke trial is feasible.