Microanatomy of the excised human spinal cord and the cervicomedullary junction examined with high-resolution MR imaging at 9.4 Tesla.

PURPOSE To study in detail the MR anatomy of the spinal cord and the cervicomedullary junction that could serve as a reference for clinical MR studies.

METHODS Specimens of fresh human spinal cord and formalin-fixed cervicomedullary transition zones were imaged with a 9.4-T vertical bore magnet. Using a multisection spin-warp pulse sequence the parameters were selected to produce essentially proton density images.

RESULTS The images obtained depict the microanatomical organization of the spinal cord and cervicomedullary junction. In the spinal cord, the central gray has the expected higher signal intensity compared with the white matter, which is, apart from its darker general appearance, characterized by the presence of a dense radially structured neuroglial framework of high signal intensity. Anatomically more complex regions such as the dorsal root entry zone, the adjacent posterior horn complex, and the crossing fibers of the cervicomedullary junction are seen as well as parts of the microvascular system.

CONCLUSION Although cellular details are still beyond the limits of this investigation, the images at 9.4 T show the spinal cord and cervicomedullary junction with detail comparable to low-power microscopic images of fixed sections, especially with respect to distinguishing gray and white matter, nuclei, tracts, and angioarchitecture.