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Updated: Nov 2, 2025
Magnetic Resonance Imaging of Multiple Sclerosis at 7.0 Tesla
Published on: February 19, 2021
Nonlesional diffusely abnormal appearing white matter in clinically isolated syndrome: Prevalence, association with
R Davis Holmes1, Irene M Vavasour1, Jamie Greenfield2
1Department of Radiology, University of British Columbia, Vancouver, British Columbia, Canada.
Background And Purpose:
While diffusely abnormal white matter (DAWM) is a nonlesional MRI abnormality identified in ∼25% of patients with multiple sclerosis (MS), it has yet to be investigated in patients at an earlier disease stage, namely clinically isolated syndrome (CIS). The goals of this study were to (1) determine the prevalence of DAWM in patients with a CIS suggestive of MS, (2) evaluate the association between DAWM and demographic, clinical, and MRI features, and (3) evaluate the prognostic significance of DAWM on conversion from CIS to MS.
Methods:
One hundred and forty-two CIS participants were categorized into DAWM and non-DAWM groups at baseline and followed for up to 24 months or until MS diagnosis. The primary outcome was conversion to MS (2005 McDonald criteria) within 6 months.
Results:
DAWM was present in 27.5% of participants, and was positively associated with brainstem symptom onset, receiving corticosteroids, dissemination in space, and T2 lesion volume. DAWM was associated with an increased risk of conversion to MS over 6 months after adjustment for age and disability (hazard ratio [HR] = 2.24, p = 0.004). This association remained at a trend-level after adjustment for high-risk imaging features (HR = 1.68, p = 0.10).
Conclusions:
DAWM is present in a similar proportion of patients with CIS and clinically definite MS, and it is associated with increased risk of conversion to MS over 6 months.
Insights
Diffusely abnormal white matter (DAWM) is common in clinically isolated syndrome (CIS) and increases the risk of conversion to multiple sclerosis (MS). This finding suggests DAWM is an early indicator of MS progression.
Area of Science:
- Neuroimaging
- Neurology
- Radiology
Background:
- Diffusely abnormal white matter (DAWM) is a nonlesional MRI finding in approximately 25% of multiple sclerosis (MS) patients.
- DAWM has not been previously studied in patients with clinically isolated syndrome (CIS), an earlier stage of MS.
Purpose of the Study:
- Determine the prevalence of DAWM in CIS patients suggestive of MS.
- Assess the association between DAWM and demographic, clinical, and MRI characteristics.
- Evaluate the prognostic value of DAWM for conversion from CIS to MS.
Main Methods:
- 142 CIS participants were classified into DAWM and non-DAWM groups.
- Participants were followed for up to 24 months or until MS diagnosis.
- Conversion to MS (2005 McDonald criteria) within 6 months was the primary outcome.
Main Results:
- DAWM was identified in 27.5% of CIS participants.
- DAWM correlated with brainstem symptom onset, corticosteroid treatment, dissemination in space, and T2 lesion volume.
- DAWM significantly increased the risk of conversion to MS within 6 months (HR=2.24, p=0.004), even after adjusting for high-risk imaging features (HR=1.68, p=0.10).
Conclusions:
- DAWM occurs in a similar proportion of patients with CIS and clinically definite MS.
- DAWM is associated with an elevated risk of conversion to MS within 6 months in CIS patients.
