Prevalence of Radiologically Isolated Syndrome and White Matter Signal Abnormalities in Healthy Relatives of Patients with Multiple Sclerosis

Abstract

BACKGROUND AND PURPOSE:The exact prevalence of WM signal abnormalities in healthy relatives of MS patients and their impact on disease development has not been fully elucidated. The purpose of this study was to compare WM signal abnormality characteristics and the prevalence of radiologically isolated syndrome in healthy control subjects selected randomly from the population with the healthy relatives of patients with MS.

Incidence of Radiologically Isolated Syndrome: A Population-Based Study

“…The few studies conducted have been hospital-based or studied the prevalence of RIS in selected cohorts such as in MS relatives. 17,22,28 In a study of unexpected MR imaging findings suggestive of MS in a tertiary hospital in Pakistan, a frequency of 0.7% was reported in the age group 15-40 years. 22 In a hospital-based study performed by us at a tertiary hospital in Stockholm, Sweden, we found an RIS fre- quency of 0.05% in all ages and 0.15% in the same age range as that in the study in Pakistan.…”

“…Meanwhile, the study from Pakistan showed a higher frequency of RIS, despite a lower incidence and prevalence of MS in the region. 23,24,30,31 Gabelic et al 28 showed, in a smaller study in relatives of patients with MS, that 3% fulfilled the RIS criteria by using the DIS-Barkhof criteria, and 10%, with the DIS-Swanton criteria. In healthy volunteers, they found RIS in 2.4% according to the DIS-Barkhof and 3.7% by using DIS-Swanton criteria.…”

“…The Okuda criteria for RIS, summarized in On-line Table 1, were used. 3 Similar to a previous study, 28 radiologic DIS was assessed according to both the original implementation with the Barkhof classification (DIS-Barkhof) 4 and with the more recent Swanton classification (DIS-Swanton) 26,27 to study the effect of the 2 different classifications on the RIS incidence. Table 1 compares the 2 DIS classifications. The screening of all patients was conducted in several steps, illustrated in Fig 1. First, all brain MR imaging scans obtained in 2013 were anonymized and systematically evaluated by a senior radiologist (A.A.).…”

Evoked potentials and other guiding factors of conversion from radiologically isolated syndrome to definite multiple sclerosis

“…Studies have been published in which demyelinating lesions were reported in less than 0.5% of the radiological scans of asymptomatic patients without any complaints (13)(14)(15). RIS is seen more frequently in people with family members with MS than those without (16). Data of the twin studies also support this statement.…”

Radiologically Isolated Syndrome: An Overview

“…In a recent study using 3 T MR imaging, about 3% of healthy relatives of MS patients and 2.4% of non-familial healthy control subjects showed white matter lesions suggestive of demyelination according to Barkhof criteria. 5 In another study, the prevalence of white matter lesions was 7% in asymptomatic first degree relatives of MS patients using Barkhof and other MRI diagnostic criteria for MS. 6 The clinical significance and prognostic implication of subclinical lesions in patients with RIS remains controversial. There is some evidence to suggest that the patients with RIS are at increased risk of developing MS over time with approximately two thirds showing radiological progression and one 7 In a study of 44 patients diagnosed with RIS and followed longitudinally, more than half (24 of 41) showed radiological progression within an average of 2.7 years and 30% (10 of 30) went on to develop clinical symptoms leading to the diagnosis of clinically isolated syndrome (CIS) or clinically definite MS (CDMS).…”