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Demonstrating neurological damage over time, referred to as dissemination in time (DIT), may not be required to diagnose multiple sclerosis (MS) in all patients, according to research published in Neurology.

 For patients with a typical MS presentation and an MRI showing high fulfillment of dissemination in space (DIS) criteria, the diagnosis of MS “could be established and treatment started without the need for further testing,” study authors noted. A diagnosis of MS could be made in patients at very high intuitive risk, such as those with lesions in four or more typical regions, who also have no gadolinium enhancement and are unable or unwilling to undergo a lumbar puncture.

“Using DIS alone could simplify the workup of patients with suspected MS,” Wallace J. Brownlee, MD, and colleagues wrote, highlighting the potential for earlier intervention in diagnosed cases.

The researchers recruited 244 patients with a first demyelinating event who were examined with brain and spinal cord MRI within 3 months of onset. They retrospectively applied DIS criteria to baseline scans requiring lesions in at least two of the four regions. They also investigated the performance of each set of DIS criteria under the 2017 McDonald criteria, requiring both DIS plus DIT on MRI or cerebrospinal fluid-specific oligoclonal bands.

DIT May Not be Needed to Confirm MS Diagnosis

Baseline scans showed that 66% of patients met the standard DIS criteria, with lesions in at least two of the four regions. Specifically, 45% had lesions in at least three regions and 20% had lesions in all four. DIT on MRI or positive oligoclonal bands was evident in 43% of patients.

Over a mean follow-up of 11.2 years, 77% of patients were diagnosed with MS using the McDonald criteria, with 49% having a second clinical attack and 70% exhibiting new lesions on MRI.

Dr. Brownlee and colleagues also assessed whether various DIS criteria independently could support a diagnosis without needing evidence of neurologic damage over time. Sensitivity was 84% when two DIS regions were required, decreasing to 58% for three groups and 26% for four regions. In contrast, specificity rose from 91% with two regions involved to 98% for three regions, reaching 100% when all four regions were affected.

A subgroup analysis including the optic nerve as a fifth DIS region demonstrated a similar trend—sensitivity declined as the number of regions increased, but specificity increased to 100% when four or five regions were needed.

“DIT … may not be necessary to confirm a diagnosis of MS in patients with typical clinical presentations and DIS in [at least] four regions, facilitating the application of the criteria in clinical practice and streamlining MS diagnosis,” the authors wrote.