Low-Field (64 mT) Portable MRI for Rapid Point-of-Care Diagnosis of Dissemination in Space in Patients Presenting with Optic Neuritis
Bibliographic record
Abstract
ABSTRACT BACKGROUND AND PURPOSE: Low-field 64mT portable brain MRI (pMRI) has recently shown diagnostic promise for MS. This study aimed to evaluate the utility of pMRI in assessing dissemination in space (DIS) in patients presenting with optic neuritis and determine whether deploying pMRI in the MS clinic can shorten the time from symptom onset to MRI. MATERIALS AND METHODS: Newly diagnosed optic neuritis patients referred to a tertiary academic MS center from July 2022 to January 2024 underwent both point-of-care pMRI and subsequent conventional 3T MRI (cMRI). Images were evaluated for periventricular (PV), juxtacortical (JC) and infratentorial (IT) lesions. DIS was determined on brain MRI per 2017 McDonald criteria. Test characteristics were computed using cMRI as the reference. Interrater and intermodality agreement between pMRI and cMRI were evaluated using Cohen’s kappa. Time from symptom onset to pMRI and cMRI during the study period was compared to the preceding 1.5 years before pMRI implementation using Kruskal-Wallis with post-hoc Dunn’s tests. RESULTS: Twenty patients (median age: 32.5 [IQR, 28-40]; 80% females) were included, of whom 9 (45%) and 5 (25%) had DIS on cMRI and pMRI, respectively. Median time interval between pMRI and cMRI was 7 days (IQR, 3.5-12.5). Interrater agreement was very good for PV (95%, κ=0.89), and good for JC and IT lesions (90%, κ=0.69 for both). Intermodality agreement was good for PV (90%, κ=0.80) and JC (85%, κ=0.63), and moderate for IT lesions (75%, κ=0.42) and DIS (80%, κ=0.58). pMRI had a sensitivity of 56% and specificity of 100% for DIS. The median time from symptom onset to pMRI was significantly shorter (8.5 days [IQR 7-12]) compared to the interval to cMRI before pMRI deployment (21 days [IQR 8-49], n=50) and after pMRI deployment (15 days [IQR 12-29], n=30) (both p<0.01). Time from symptom onset to cMRI in those periods was not significantly different (p=0.29). CONCLUSIONS: In optic neuritis patients, pMRI exhibited moderate concordance, moderate sensitivity and high specificity for DIS compared to cMRI. Its integration into the MS clinic reduced the time from symptom onset to MRI. Further studies are warranted to evaluate the role of pMRI in expediting early MS diagnosis and as an imaging tool in resource-limited settings. ABBREVIATIONS: pMRI = portable MRI; cMRI = conventional MRI; pwMS = patients with MS; PV = periventricular; JC= juxtacortical; IT = infratentorial; DIS = dissemination in space
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".