From the Division of Neuroradiology, Department of Medical Imaging (T.R.L., S.S., A.W.L., Y.A.C., S.M. A.B.), St Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.
Department of Ophthalmology and Vision Sciences (J.M.), University of Toronto, Toronto, Ontario, Canada.
AJNR Am J Neuroradiol. 2024 Nov 7;45(11):1819-1825. doi: 10.3174/ajnr.A8395.
Low-field 64 mT portable brain MRI has recently shown diagnostic promise for MS. This study aimed to evaluate the utility of portable MRI (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.
Newly diagnosed patients with optic neuritis referred to a tertiary academic MS center from July 2022 to January 2024 underwent both point-of-care pMRI and subsequent 3T conventional 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 by using cMRI as the reference. Interrater and intermodality agreement between pMRI and cMRI were evaluated by using the Cohen κ. Time from symptom onset to pMRI and cMRI during the study period was compared with the preceding 1.5 years before pMRI implementation by using Kruskal-Wallis with post hoc Dunn tests.
Twenty patients (median age: 32.5 years [interquartile range {IQR}, 28-40]; 80% women) 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 with the interval to cMRI before pMRI deployment (21 days [IQR 8-49], = 50) and after pMRI deployment (15 days [IQR 12-29], = 30) (both < .01). Time from symptom onset to cMRI in those periods was not significantly different (= .29).
In patients with optic neuritis, pMRI exhibited moderate concordance, moderate sensitivity, and high specificity for DIS compared with 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.
最近，低场 64mT 便携式脑部 MRI 已显示出在 MS 诊断方面的潜力。本研究旨在评估便携式 MRI（pMRI）在评估视神经炎患者空间性弥散（DIS）方面的效用，并确定在 MS 诊所中部署 pMRI 是否可以缩短从症状出现到 MRI 的时间。
2022 年 7 月至 2024 年 1 月，三级学术 MS 中心新诊断为视神经炎的患者接受了床边 pMRI 和随后的 3T 常规 MRI（cMRI）检查。评估了脑室周围（PV）、皮质下（JC）和颅后窝（IT）病变。根据 2017 年 McDonald 标准在脑 MRI 上确定 DIS。通过使用 cMRI 作为参考，计算了测试特征。使用 Cohen κ 评估 pMRI 和 cMRI 之间的组内和组间一致性。通过使用 Kruskal-Wallis 检验和事后 Dunn 检验，比较了在研究期间从症状出现到 pMRI 和 cMRI 的时间与 pMRI 实施前 1.5 年的时间。
共纳入 20 名患者（中位年龄：32.5 岁[四分位距 {IQR}，28-40]；80%为女性），其中 9 名（45%）和 5 名（25%）患者在 cMRI 和 pMRI 上分别存在 DIS。pMRI 和 cMRI 之间的中位时间间隔为 7 天（IQR，3.5-12.5）。PV 的组内一致性非常好（95%，κ=0.89），JC 和 IT 病变的组内一致性良好（90%，κ=0.69 ）。PV（90%，κ=0.80）和 JC（85%，κ=0.63）的组间一致性良好，而 IT 病变（75%，κ=0.42）和 DIS（80%，κ=0.58）的组间一致性为中度。pMRI 对 DIS 的敏感性为 56%，特异性为 100%。与 pMRI 部署前（21 天[IQR，8-49]，=50）和部署后（15 天[IQR，12-29]，=30）相比，从症状出现到 pMRI 的中位时间明显缩短（8.5 天[IQR，7-12]，=50）（均<.01）。在此期间，从症状出现到 cMRI 的时间无显著差异（=0.29）。
在视神经炎患者中，与 cMRI 相比，pMRI 对 DIS 的组内一致性、敏感性和特异性中等。它在 MS 诊所中的整合缩短了从症状出现到 MRI 的时间。需要进一步的研究来评估 pMRI 在加速 MS 早期诊断中的作用以及在资源有限的情况下作为影像学工具的作用。
