Choroid plexus volume is enlarged in clinically isolated syndrome patients with optic neuritis

Abstract

Objectives: People with Multiple Sclerosis (MS) have a larger choroid plexus (CP) volume than healthy controls. We investigated CP volume in early MS by quantitatively assessing brain MRI scans in patients presenting with optic neuritis (ON) as a clinically isolated syndrome (CIS), compared to a cohort with established Relapsing Remitting Multiple Sclerosis (RRMS) and healthy controls. Methods: Pre- and post-gadolinium 3D-T1, 3D FLAIR and diffusion tensor images were acquired from 44 CIS ON patients at baseline, 1, 3, 6 and 12 months after the onset of ON. Fifty RRMS patients and 50 healthy controls were also included for comparison. Results: ANOVA revealed significantly larger CP volumes in both ON CIS and RRMS groups compared to healthy controls (p<0.001 for both), but no difference between ON CIS and RRMS patients (p=0.9) Twenty-three ON CIS patients who converted to CDMS during 10 years of follow-up demonstrated CP volume similar to RRMS patients, but significantly larger compared to healthy controls (p<0.001). Increased CP volume was identified even in a sub-group of patients without MS-like lesions at baseline (p<0.001). A significant (~6%) transient increase of CP volume was observed following a new bout of inflammation, which, however, returned to pre-inflammatory state few months later. CP volume was not associated with the severity of acute inflammation of the optic nerve or long-term optic nerve axonal loss, not with brain lesion load or severity of tissue damage within lesions. Interpretation: Our data demonstrate that enlarged CP can be observe very early in a disease, transiently reacts to acute inflammation, but not associated with the degree of tissue destruction.