頚髄症における MRI 髄内輝度変化と臨床成績の関係

抄録

Sixty-four patients with cervical myelopathy underwent spinous process-splitting laminoplasty. In terms of recovery rate, there were no significant differences between patients showing a high T2 without a low T1 signal and those showing no change, when compared using the JOA scoring system for cervical myelopathy. However, the recovery rate in patients showing a high T2 with a low T1 signal was significantly lower than that in patients showing a high T2 without a low T1 signal. Patients showing regression of the change in intramedullary signal intensity had a significantly better outcome in terms of recovery rate than patients without regression. The intramedullary signal changes in cervical myelopathy generally indicate myelomalacia and cord gliosis. The stages of myelomalacia can be divided into early, intermediate and late stages. In the early stage, a high T2 signal indicates reversible changes such as cord edema, inflammation, vascular ischemia, or demyelination. In the intermediate stage, cystic necrosis occurs gradually as the lesion progresses, a low T1 change appears, and in the last stage irreversible pathological changes occur, such as cavitation, a decrease of cellular density, and motor neuron loss. Thus, a high T2 signal change does not indicate a poor prognosis, and reflects a broad spectrum of spinal cord reparative potential. However, a low T1 change indicates a poor prognosis.