Toubasi Ahmad A, Cutter Gary, Gheen Caroline, Vinarsky Taegan, Yoon Keejin, AshShareef Salma, Adapa Pragnya, Gruder Olivia, Taylor Stephanie, Eaton James E, Xu Junzhong, Bagnato Francesca
Neuroimaging Unit, Neuroimmunology Division, Department of Neurology, Vanderbilt University Medical Center (VUMC), Nashville, TN (A.A.T., C.G., T.V., K.Y., S.A., P.A., F.B.).
Department of Biostatistics, School of Public Health, The University of Alabama at Birmingham, Birmingham, AL (G.C.).
Acad Radiol. 2025 Feb;32(2):1002-1014. doi: 10.1016/j.acra.2024.08.048. Epub 2024 Sep 14.
Several quantitative magnetic resonance imaging (MRI) methods are available to measure tissue injury in multiple sclerosis (MS), but their pathological specificity remains limited. The multi-compartment diffusion imaging using the spherical mean technique (SMT) overcomes several technical limitations of the diffusion-weighted image signal, thus delivering metrics with increased pathological specificity. Given these premises, here we assess whether the SMT-derived apparent axonal volume (V) provides a better tissue classifier than the diffusion tensor imaging (DTI)-derived axial diffusivity (AD) in the white matter (WM) of MS brains.
Forty-three treatment-naïve people with newly diagnosed MS, clinically isolated syndrome, or radiologically isolated syndrome and 18 healthy controls (HCs) underwent a 3.0 Tesla MRI inclusive of T-weighted (T-w) and T-w fluid-attenuated inversion recovery (FLAIR) sequences, and multi-b shell diffusion-weighted imaging. In patients only, pre- and post-gadolinium diethylenetriamine penta-acetic acid T-w sequences were obtained for the evaluation of contrast-active lesions (CELs). V and AD were calculated in T-lesions, chronic black holes (cBHs), and normal appearing (NAWM) in patients and normal WM (NWM) in HCs. V and AD values were compared across all the possible combinations of these regions. CELs were excluded from the analyses.
V differed in all comparisons (p ≤ 0.047 by paired t-test); AD differed in most comparisons (p < 0.001) except between NAWM and NWM, and between cBHs and T-lesions. V had higher accuracy (p ≤ 0.029 by DeLong test) and larger effect size (p ≤ 0.038 by paired t-test) than AD in differentiating areas with even minimal tissue injury.
V provides a better radiological quantitative discriminator of different degrees of axonal-mediated tissue injury even between areas with expected minimal pathology. Our data support further studies to assess the readiness of V as a measure of outcome for clinical trials on neuroprotection in MS.
有几种定量磁共振成像（MRI）方法可用于测量多发性硬化症（MS）中的组织损伤，但其病理特异性仍然有限。使用球面均值技术（SMT）的多室扩散成像克服了扩散加权图像信号的几个技术限制，从而提供了具有更高病理特异性的指标。基于这些前提，我们在此评估在MS脑白质（WM）中，SMT衍生的表观轴突体积（V）是否比扩散张量成像（DTI）衍生的轴向扩散率（AD）提供更好的组织分类器。
43例新诊断为MS、临床孤立综合征或放射学孤立综合征且未接受过治疗的患者以及18名健康对照（HC）接受了3.0特斯拉MRI检查，包括T加权（T-w）和T-w液体衰减反转恢复（FLAIR）序列以及多b值壳扩散加权成像。仅在患者中，获取钆双醋二胺五乙酸前后的T-w序列以评估对比增强病灶（CEL）。在患者的T病灶、慢性黑洞（cBH）和正常表现脑白质（NAWM）以及HC的正常脑白质（NWM）中计算V和AD。比较这些区域所有可能组合的V和AD值。分析中排除CEL。
所有比较中V均有差异（配对t检验，p≤0.047）；除NAWM与NWM之间以及cBH与T病灶之间外，大多数比较中AD有差异（p<0.001）。在区分即使有最小组织损伤的区域时，V比AD具有更高的准确性（DeLong检验，p≤0.029）和更大的效应量（配对t检验，p≤0.038）。
即使在预期病理最小的区域之间，V也能更好地对不同程度的轴突介导组织损伤进行放射学定量鉴别。我们的数据支持进一步研究，以评估V作为MS神经保护临床试验结果指标的适用性。
