Conventional magnetic resonance sequences in multiple sclerosis

The role of magnetic resonance imaging (MRI) in multiple sclerosis (MS) has received considerable attention in recent years. MRI has the potential to provide indices of disease activity and progression in clinical trials. Moreover, there is now widespread agreement that conventional MRI sequences are useful not only in diagnosing the disease but also in evaluating the natural course of the disease and the response to therapy. Conventional spin echo (CSE) sequences are widely accepted as sensitive techniques for the evaluation and quantification of brain MS lesions. Fast spin echo (FSE) sequences are now used as an alternative to CSE. They have the advantage of a considerable reduction in imaging time. Fast-fluid attenuation inversion recovery (fast-FLAIR) sequences, in which the signal from cerebrospinal fluid is suppressed, also provide a reliable means to evaluate the total lesion burden in patients with MS. Despite some limitations in the detection of infratentorial lesions, Fast-FLAIR sequences are useful in clinical studies. Compared with lesions load on conventional T2-weighted sequences, an increase in hypointense lesion load on CSE T1-weighted sequences correlates more strongly with increased disability in MS patients. This might be an additional useful MRI parameter to monitor disease progression in long-term studies. Gadolinium-enhanced T1-weighted images provide highly sensitive markers for detecting MRI activity, which represent the primary MRI endpoint for screening promising disease-modifying therapies, especially in phase II trials.