MRI and magnetization transfer imaging changes in the brain and cervical cord of patients with Devic's neuromyelitis optica

Objectives: To assess MRI and magnetization transfer (MT) imaging changes in the brain and cervical cord from patients with Devic's neuromyelitis optica (DNO), and to compare them with those from patients with MS. Background: In MS, MT imaging detects changes within the normal-appearing brain tissue (NABT). MS lesions in the ord usually are isointense on T1-weighted images. No study has investigated these two aspects in patients with DNO. Methods: The authors obtained dual echo, fast fluid-attenuated inversion recovery, T1-weighted, and MT scans of the brain from 8 DNO patients, 10 MS patients, and 9 healthy volunteers. T2-weighted, short-tau inversion recovery, T1-weighted, and MT scans of the cervical cord also were obtained. The authors identified lesions visible on the different scans and quantified the volumes for those in the brain. MT ratio (MTR) histogram analysis of the NABT and of the entire cervical cord also was performed. Results: No brain abnormalities were found on the T2-weighted scans from healthy volunteers and from seven DNO patients. No significant difference was found for any of the NABT-MTR histogram metrics between DNO patients and controls, whereas MS patients had a significantly lower histogram average MTR and peak height. No abnormalities were seen on any of the scans of the cervical cord from healthy volunteers. All DNO patients had a single lesion longer than two vertebral segments. Five of them were hypointense on T1-weighted scans. The authors identified 24 cord lesions from MS patients: 22 were shorter than two vertebral segments and none was hypointense. There was no difference in cervical cord MTR histogram metrics between DNO and MS patients. Conclusions: This study demonstrates that patients with Devic's neuromyelitis optica (DNO) and MS have different imaging characteristics of the brain and cervical cord. This provides further evidence that DNO is a clinical entity separate from MS.