What are the gray and white matter volumes of the human spinal cord?

Abstract

The gray matter of the spinal cord is the seat of somata of various types of neurons devoted to the sensory and motor function of the limbs and trunk. The volume of the spinal gray matter is an indicator of the local neuronal processing and this can decrease due to atrophy associated with degenerative diseases and injury. Nevertheless, the absolute volume of the human spinal cord has rarely been reported, if ever. Here, we use high-resolution magnetic resonance imaging, with a cross-sectional resolution of 50 x 50m2, to estimate the total gray and white matter volume of two post mortem human spinal cords. Segregation of gray and white matter was accomplished using deep learning image segmentation. The gray and white matter volumes were found to be 2.87 and 11.33 ml, respectively for a female and 3.55 and 19.33 ml, respectively for a male. The gray and white matter profiles along the vertebral axis were found to be strikingly similar and the volumes of the cervical, thoracic and lumbosacral sections were almost equal. NEW AND NOTEWORTHYHere, we combine high field MRI (9.4T) and deep learning for a post-mortem reconstruction of the gray and white matter in a human spinal cord. We report a minuscule total volume of the gray matter of 2.87 ml for a female and 3.55 ml for a male. The gray matter volumes are unexpectedly small. For comparison, these volumes correspond approximately to the distal digital of the little finger.