Imaging neuronal and axonal degeneration in multiple sclerosis.

Neuronal and axonal damage has become an important issue in multiple sclerosis. This has been emphasised by recent magnetic resonance imaging (MRI) studies that have shown evidence of axonal damage in both lesional and non-lesional white matter and in grey matter. In this respect, proton MR spectroscopy (by monitoring levels of Nacetylaspartate, a putative marker of axonal integrity) and computed measurements of cerebral volumes have been particularly illuminating. Recent studies using these MRI measures have demonstrated that cerebral neuro-axonal damage begins and contributes to disability from the earliest stages of the disease. This implies that the apparently primary role of neuronal pathology in the pathogenesis of the disease should be given due importance and argues for the early treatment of multiple sclerosis with agents directed not only against inflammation, but also towards neuronal protection.