An improved method for spinal functional MRI with large volume coverage of the spinal cord

Purpose: To develop a spinal functional MRI (fMRI) method with three-dimensional coverage of a large extent of the spinal cord with minimal partial volume effects Materials and Methods: fMRI data of the cervical spinal cord were obtained at 1.5 T with a single-shot fast spin-echo imaging method, from thin contiguous sagittal slices spanning the cord. Thermal stimulation was applied to the palm of the hand in a block pattern with 15 degrees C for stimulation and 32 degrees C during baseline periods. Prior to analysis, the image data at each time point were reformatted into three-dimensional volumes and resliced perfectly transverse to the spinal cord. Smoothing was applied only in the superior-inferior (S/I) direction across uniform tissue types. Active voxels were then identified by means of a correlation to a model paradigm. Results: The resulting activity maps demonstrate activity primarily in ipsilateral sensory areas and in some motor areas, consistent with the spinal cord neuroanatomy. These data also demonstrate detail of the subsegmental organization of the spinal cord, as well as anatomical detail of the spinous processes and positions of nerve roots. Conclusion: The spinal fMRI method described enables large volume coverage of the spinal cord in three dimensions, with reliable and reproducible results.