A new study led by an Austrian team of researchers and published in Neurology measured the clinical utility of using optical coherence tomography (OCT) to assess the optic nerve and demonstrate dissemination in space (DIS) in diagnostic criteria of multiple sclerosis (MS).
First … what does dissemination in space mean?
A diagnosis of MS requires the demonstration of dissemination in space (DIS) and time, meaning lesions occur in more than one place in the central nervous system and at different times.
One MS diagnostic criteria includes finding lesions in at least two separate regions (out of four) of the central nervous system (CNS).
This study investigated whether adding the optic nerve region as a fifth region of the DIS criteria improves the 2017 diagnostic criteria.
Now give me some background.
These findings build on past results from a 2022 study that showed MS relapse-related damage to the retina displays the degree of damage caused to the patient’s brain.
Researchers proved that a 5-micrometer reduction in the retinal layer thickness following optic neuritis (ON) indicated a doubled risk of permanent disability after the following relapse.
And the study?
In this prospective observational study, investigators analyzed 267 MS patients, with a mean age of 31.3 years (standard deviation 8.1) and 69% female, over the course of a median observation period of 59 months (range 13-98 months).
Go on…
Investigators constructed modified DIS criteria (DIS+OCT) by adding OCT of the optic nerve to the current DIS regions based on validated thresholds for OCT inter-eye differences.
The primary endpoint of the study was the time to the second clinical attack.
Who was included in the study?
Patients with a first demyelinating event, complete information to assess DIS, and who had obtained spectral-domain OCT scans within 180 days.
Findings?
Including the optic nerve improved the diagnostic performance by increasing accuracy (DIS+OCT 81.2% vs. DIS 65.6%) and sensitivity (DIS+OCT 84.2% vs. DIS 77.9%), all without lowering specificity (DIS+OCT 52.2% vs. DIS 52.2%).
Anything else?
Fulfilling DIS+OCT criteria, defined as >2 of 5 DIS+OCT regions involved, indicated a similar risk of a second clinical attack (hazard ratio [HR] 3.6, confidence interval [CI] 1.4-14.5) compared to a 2.5-fold increased risk when fulfilling DIS criteria (HR 2.5, CI 1.2-11.8).
When the analysis was conducted according to the topography of the first demyelinating event, DIS+OCT criteria performed similarly in both ON and non-ON.
Expert opinion?
According to Gabriel Bsteh, first author of the study, “If we use [OCT] alongside the current criteria to diagnose MS, we obtain significantly more accurate results at a much earlier stage.”
“This means we can initiate treatment measures sooner, which considerably improves the long-term prognosis for patients,” he added.
Take home.
As such, adding OCT evaluation of the optic nerve as a fifth region in the current DIS criteria for MS improves diagnostic performances by increasing sensitivity without lowering specificity.
Bigger picture?
Due to the fact that early detection and diagnosis of MS play a key role in managing the disease, these findings provide medical researchers with a new avenue for improving detection modalities to prevent MS progression, such as impaired mobility and blindness.
What’s next?
The next steps for the research team will be to focus on evaluating the value of retinal layer thickness in measuring responses to MS treatment.