Evaluation of the ‘ring sign’ and the ‘core sign’ as a magnetic resonance imaging marker of disease activity and progression in clinically isolated syndrome and early multiple sclerosis

Abstract

Background: Brain lesions with a hypointense ring or core were described in multiple sclerosis on susceptibility weighted imaging. Objective: The purpose of this study was to study the evolution and prognostic relevance of susceptibility weighted imaging hypointense lesions in clinically isolated syndrome and early multiple sclerosis. Methods: Sixty-six early multiple sclerosis and clinically isolated syndrome patients were followed over a median period of 2.9 years (range 1.6-4.6 years) and underwent 3T magnetic resonance imaging including 3D susceptibility weighted imaging and T2-weighted fluid-attenuated inversion recovery. We assessed the presence of susceptibility weighted imaging hypointense core or ring lesions, and Expanded Disability Status Scale at baseline and follow-up. Results: Of 611 lesions at baseline, 64 (10.5%) had a susceptibility weighted imaging hypointense core, and 28 (4.6%) had a susceptibility weighted imaging hypointense ring. Hypointense ring lesions were larger (p < 0.001) and more T1w hypointense (p ¼ 0.002) than others. During follow-up, hypointense core lesions became susceptibility weighted imaging isointense (52 lesions, 81%); few developed into hypointense ring lesions (two lesions, 3%). Hypointense ring lesions did not shrink on T2-weighted fluid-attenuated inversion recovery images (p ¼ 0.077, trend towards more enlargement compared to others), while hypointense core lesions more often shrunk in comparison to lesions without a hypointense core (p ¼ 0.002). The number of susceptibility weighted imaging hypointense ring lesions at baseline correlated with Expanded Disability Status Scale progression at follow-up (p ¼ 0.021, R ¼ 0.289). Conclusion: In our cohort of patients with clinically isolated syndrome or early multiple sclerosis, susceptibility weighted imaging hypointense ring lesions were only rarely detectable, but did not shrink and were associated with future disability progression.

Iron Rims as an Imaging Biomarker in MS: A Systematic Mapping Review

“…Sixteen papers reported the presence of IRLs in MS subtypes [ 14 , 16 , 19 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ]. Most of the publications examined patients with RRMS [ 22 , 24 , 29 , 31 , 32 , 35 , 36 , 37 ].…”

“…The highest rate of IRL presence was found in RRMS (36%) followed by SPMS (27%) while the benign MS and clinically isolated syndrome (CIS) had the lowest percentage of (5%). One study each was found reporting on benign MS [ 32 ] and radiologically isolated syndrome (RIS) [ 34 ] while RRMS was most frequently reported in eight studies [ 22 , 23 , 24 , 26 , 29 , 31 , 32 , 36 ] followed by SPMS in six studies [ 16 , 23 , 28 , 29 , 30 , 31 ]. Interestingly, IRLs were absent in NMOSD [ 19 ], Susac’s syndrome [ 20 ] and ischemic lesions [ 21 ].…”

“…IRLs presence was related to poor cognitive performance and disability in 9 of 10 papers [ 14 , 17 , 27 , 29 , 32 , 34 , 40 , 41 , 42 , 43 ]. However, Kilsdonk et al (2014) reported the lack of relationship between IRLs and physical disability [ 28 ].…”

“…The total lesion counts across studies ranged from 44 to 3211 lesions. Four studies showed similar prevalence of IRLs presence, approximately ~10% [ 17 , 28 , 34 , 44 ]. However, Absinta et al (2013) using 7T scanner found IRLs in acute gadolinium-enhancing lesions and found their presence in 75% (33/44 lesions), but in 2018 the same group reported in their 3T and 7T longitudinal study the presence of IR in chronic lesions was 50% (27/54 lesions) [ 45 , 46 ].…”

“…However, Absinta et al (2013) using 7T scanner found IRLs in acute gadolinium-enhancing lesions and found their presence in 75% (33/44 lesions), but in 2018 the same group reported in their 3T and 7T longitudinal study the presence of IR in chronic lesions was 50% (27/54 lesions) [ 45 , 46 ]. Both Danial and Blindenbacher shared a similar prevalence of 5% (16/306; 28/611 respectively) in acute lesions [ 17 , 34 ]. The MRI techniques used to detect rims in these studies were different, namely, Quantitative Susceptibility Mapping, (QSM), SWI, R2*, FLAIR with the mixed-use of both 3T and 7T MRI scanners.…”