Serial quantitative MR assessment of optic neuritis in a case of neuromyelitis optica, using Gadolinium- "enhanced" STIR imaging

Quantitative Contrast-Enhanced MR Imaging of the Optic Nerve

During the acute stages of optic neuritis damage to the blood-optic nerve barrier can be detected using i.v. paramagnetic contrast-enhanced MR imaging. Quantification of the enhancement pattern of the optic nerve, intraorbital fat and muscle was determined in 15 normal subjects using 3 fat-suppression MR imaging methods: T1-weighted spin-echo and spoiled gradient-echo sequences preceded by a fat-frequency selective pulse (FATSAT + SE and FATSAT + SPGR, respectively) and a pulse sequence combining CHOPPER fat suppression with a fat-frequency selective preparation pulse (HYBRID). Pre- and postcontrast-enhanced studies were acquired for FATSAT + SE and FATSAT + SPGR. There was no significant enhancement of the optic nerve by either method (mean increase of 0.96% and 5.3%, respectively), while there was significant enhancement in muscle (mean 118.2% and 108.2%), respectively; p < 0.005) and fat (mean increase of 13% and 37%, respectively; p < 0.05). Postcontrast optic nerve/muscle signal intensity ratios (mean, SD) were 0.51 (0.07), 0.58 (0.05) and 0.75 (0.05) for FATSAT + SE, FATSAT + SPGR and HYBRID, respectively. These results suggest a practical methodology and range of values for normal signal intensity increases and ratios of tissue signal that can be used as objective measures of optic neuritis for natural history studies and treatment trials.

Spinal-cord MRI in multiple sclerosis: conventional and nonconventional MR techniques

Multiple sclerosis is a diffuse disease of the central nervous system, and MRI of the spinal cord is highly recommended in the clinical evaluation of patients suspected of having multiple sclerosis. Within the new diagnostic criteria, spinal cord MRI increases sensitivity and possibly specificity for MS, but further work is needed to investigate other criteria that may give greater weight to the presence of cord lesions in patients with clinically isolated syndromes or suspected relapsing-remitting multiple sclerosis. Techniques should be further studied and validated in studies comparing these techniques with clinical status and histopathology, however.

Demyelinating and infectious diseases of the spinal cord

Spinal cord diseases generally have distinctive clinical findings that reflect dysfunction of particular sensory or motor tracts. The abnormalities on MR images reflect the pathologic changes that occur in the affected pathways. The complexity and the wide spectrum of diseases affecting the spinal cord require a profound knowledge of neuropathology and exactly tuned imaging strategies. This article describes and illustrates the clinical and imaging characteristics in various demyelinating and infectious conditions of the spinal cord.

MRI of neuromyelitis optica: evidence for a distinct entity

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