Marshall Madeleine, Aphiwatthanasumet Kingkarn, Mougin Olivier, Stadelmann Christine, Morgan Paul S, Dineen Rob A, Gowland Penny, Evangelou Nikos, Clarke Margareta A
Mental Health and Clinical Neurosciences Academic Unit, School of Medicine, University of Nottingham, Nottingham, UK.
Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK.
J Neuroimaging. 2025 May-Jun;35(3):e70044. doi: 10.1111/jon.70044.
Chronic active multiple sclerosis (MS) lesions represent a particularly destructive subset of lesions on pathology. However, their imaging correlates, including paramagnetic rim lesions (PRLs) detected on susceptibility-weighted imaging, lack sensitivity and are difficult to implement in clinical practice. This exploratory, longitudinal study investigates the prevalence and temporal dynamics of a novel imaging marker, T-dark rims, and their relationship with PRLs observed on quantitative susceptibility mapping (QSM).
Four untreated people with MS underwent 7-Tesla MRI scanning six times over a period of 36 weeks. New and pre-existing lesions were analyzed for the presence and temporal evolution of T-dark and QSM rims. Quantitative T values were derived using B maps, and the relationship between rim status and lesion size was evaluated.
Of the 159 baseline lesions, 22 (14%) had T-dark rims, 11 (7%) had QSM rims, and five lesions had both. T-dark and QSM rims showed temporal changes, with T-dark rims preceding new QSM rim appearance in three out of four (75%) lesions. Eleven out of 20 (55%) newly formed lesions had T-dark rims, with a T-dark rim present in all new lesions over 100 mm. Small new lesions lacked discernible rims, but their overall T values aligned with those of larger lesion T-dark rims implying shared pathological processes.
T-dark rims were more common than QSM rims, with greater prevalence in newly formed lesions. We propose they represent edema and inflammation associated with early stages of chronic active lesion formation visible despite, not because of, iron accumulation.
慢性活动性多发性硬化（MS）病灶在病理学上是一类具有特别破坏性的病灶亚群。然而，其影像学相关表现，包括在磁敏感加权成像上检测到的顺磁性边缘病灶（PRL），缺乏敏感性且在临床实践中难以应用。这项探索性纵向研究调查了一种新型影像学标志物——T暗边的患病率和时间动态变化，以及它们与在定量磁敏感图谱（QSM）上观察到的PRL的关系。
4名未经治疗的MS患者在36周内接受了6次7特斯拉MRI扫描。对新出现的和既往存在的病灶分析T暗边和QSM边的存在情况及时间演变。使用B图得出定量T值，并评估边缘状态与病灶大小之间的关系。
在159个基线病灶中，22个（14%）有T暗边，11个（7%）有QSM边，5个病灶两者都有。T暗边和QSM边显示出时间变化，在四分之三（75%）的病灶中，T暗边先于新的QSM边出现。20个新形成的病灶中有11个（55%）有T暗边，所有直径超过100mm的新病灶都有T暗边。小的新病灶没有可辨别的边缘，但它们的总体T值与较大病灶的T暗边一致，这意味着存在共同的病理过程。
T暗边比QSM边更常见，在新形成的病灶中患病率更高。我们认为它们代表与慢性活动性病灶形成早期阶段相关的水肿和炎症，尽管可见但并非由于铁沉积。
