Magnetic Resonance Imaging to Detect Brain Damage in Patients With Multiple Sclerosis

OBJECTIVE: Among the factors contributing to the poor identification of grey and white matter pathology of multiple sclerosis (MS) patients, the low signal-to-noise ratio and consequential poor resolution of magnetic resonance imaging (MRI) obtained at conventional magnetic fields (i.e. 1.5 Tesla) play a significant role. Preliminary results suggest that 7T-MRI has the capability to disclose characteristics of chronic white matter lesions' heterogeneity in MS, not seen at lower field MRI. We now aim to extend those results by investigating whether lesions' heterogeneous appearance pertain not only to chronic lesions, i.e. those studied thus far, but also to newly formed lesions, i.e. those enhancing upon gadolinium injection. The latter can be identified only by imaging at 7T with contrast injection those MS patients known to already have active lesions.

STUDY POPULATION: Up to 145 patients (age range: 18-65, range in the Expanded Disability Status Scale: 0-4.5) with definite MS according to Poser criteria or other diseases of the central nervous system resembling MS from an imaging stand point and up to 120 age/gender-matched healthy volunteers will be enrolled.

DESIGN: Patients previously shown to meet both the clinical and MRI criteria for MS and an equivalent number of gender- and age-matched healthy volunteers will be studied. Initially, both patients and healthy individuals will have conventional 1.5Tesla MRI T1-weighted scans without contrast, whereas patients will also have post-contrast scans. Next, both groups of subjects will be imaged on both the 3 Tesla and 7 Tesla MRIs in a random order. In each 3 Tesla and 7 Tesla MRI study the examination will include the following sequences: 3 dimensional inversion-recovery-prepared fast spoiled gradient recalled images, 3D-fluid-attenuated inversion recovery and double inversion recovery in addition to T1 and T2 conventional weighted images.

A second group of 15 patients with or without clinical relapse who are known to be in an active stage of MS as seen by post-contrast MRI will be imaged. Each patient may undergo a standard 3T MRI within the two weeks before the 7T MRI (if needed, as no information regarding his/her disease status are otherwise available from 3T MRI performed under other NIB protocols). The former will allow ascertaining in advance his/her status of lesions activity, thus providing an adequate number of patients with active lesions imaged at 7T. Each patient may need to repeat his/her scan three times in case of magnetic instability during image acquisition. Additional 3T and 7T MRIs will be performed after 1 and 6 months to follow active lesions evolution over time.

A third group of patients with MS or any other disease of the central nervous system manifesting in magnetic resonance imaging with lesions of the white matter and grey matter which could mimic MS will be included. Each patient will undergo a 3T MRI inclusive of post-contrast sequences as well as a 7T MRI.

OUTCOME MEASURES: The number of cortical lesions as well as white matter and deep grey abnormalities will be computed on images obtained at 1.5, 3 and 7 Tesla MRIs. The study will not aim at conducting a formal comparison of cortical or white matters lesions seen on 3 Tesla and 7 Tesla. Instead, the goal is to provide preliminary information that can be used to design a formal analysis of the sensitivities of the two platforms in studying those abnormalities seen in MS. Active lesions found to be conspicuous upon contrast injection will be compared between T1 and gradient echo images at 7T. Additionally, the evolution of active lesions over time at 7T will be evaluated.