Detection of cortical inflammatory lesions by double inversion recovery magnetic resonance imaging in patients with multiple sclerosis

Background: A significant inflammatory pathologic disorder in the cortex of patients with multiple sclerosis ( MS) has been demonstrated by ex vivo studies. Objective: To determine the frequency, time of appearance, and clinical relevance of intracortical lesions (ICLs) in MS in vivo. Design: Double inversion recovery sequence study. Setting: Multiple Sclerosis Centre of the Veneto Region. Patients: We enrolled 380 patients (116 with clinically isolated syndrome [CIS], 163 with relapsing-remitting MS [RRMS], and 101 with secondary progressive MS [SPMS]) and 40 age- and sex-matched healthy volunteers between May 1, 2005, and December 31, 2006. Main Outcome Measures: We assessed the frequency and number of ICLs and brain parenchyma fraction, white matter T2 lesion volume, and clinical disability. Results: Although never observed in healthy volunteers, ICLs were detected in 58% of patients (36% of patients with CIS, 64% of patients with RRMS, and 73% of patients with SPMS). The number of ICLs was higher in patients with SPMS than in those with CIS or RRMS (P <.001), and patients with ICLs had a higher Expanded Disability Status Scale score (P=.004), a higher white matter T2 lesion volume (P=. 008), a lower brain parenchyma fraction (P=. 009), and a higher frequency of IgG oligoclonal bands (IgGOBs) (P <. 001) than patients without ICLs. Patients positive for IgGOBs had more ICLs than patients negative for IgGOBs (P=.02). The number of ICLs correlated with the Expanded Disability Status Scale score (r=0.48, P <.001), white matter T2 lesion volume (r=0.38, P=.001), and brain parenchyma fraction (r=-0.47, P=.001). A significant association between ICLs and male sex was observed. Conclusions: Although more frequent in patients with SPMS, ICLs were observed from the early disease stages. The ICLs were more frequently detected in patients with IgGOBs and were associated with a higher clinical disability score and male sex. The ICLs may help to define MS clinical heterogeneity and prognosis in clinical settings.