Appraisal of cerebral atrophy in multiple sclerosis by means of the corpus callosum index

The course of multiple sclerosis is characterised by the development of cerebral atrophy. It is of interest to monitor it in order to evaluate the treatment response, and the preferred technique consists in performing brain volume analyses, which are currently restricted to the field of research. To analyse the corpus callosum index (CCI) as a possible alternative to the methods based on brain segmentation. Our sample was made up of 109 patients with recently diagnosed demyelinating diseases (90 relapsing-remitting multiple sclerosis, 7 primary progressive forms and 12 isolated demyelinating syndromes), and the CCI was calculated in their first magnetic resonance brain scan, together with 101 healthy controls. The sequences of the patients were submitted to a volumetric analysis using the software package MSmetrix. The mean value of the CCI was 0.377 in patients and 0.411 in the controls, and the difference was statistically significant (p < 0.001). The CCI also showed a statistically significant correlation with the brain volume (p < 0.001; r = 0.444) and with the lesional volume in the FLAIR sequence (p < 0.001; r = -0.521), while no association was observed with the volume of grey matter (p = 0.058). The CCI is related to the overall brain volume obtained by volumetric techniques and may reflect the presence of atrophy in the initial stages of demyelinating diseases, which makes it a fast and easy to calculate alternative.