Medical Imaging Research Center, Shiraz University of Medical Sciences, Shiraz, Iran; Department of Radiology, Nemazee Hospital, Shiraz University of Medical Sciences, Shiraz, Iran; Epilepsy Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
Department of Radiology, Nemazee Hospital, Shiraz University of Medical Sciences, Shiraz, Iran.
J Med Imaging Radiat Sci. 2021 Mar;52(1):121-126. doi: 10.1016/j.jmir.2020.12.001. Epub 2021 Jan 11.
One of the most common demyelinating disorders is Multiple Sclerosis (MS), which can lead to extensive disability in patients. Appearance of active lesions can be an important sign of disease development. The correlation between the restriction of DWI signal, contrast-enhancement, and demyelinated plaque's signals were evaluated in this study.
34 MS patients with 1043 MS-plaques who had acute attacks took part in this study. Three MRI pulse-sequences, FLAIR, DWI, and post-contrast enhanced T1 weighted, were compared. Using the signal intensity of MS-lesions and normal brain tissue in FLAIR images, lesion/noise ratio (LNR) and lesion/white-matter ratio (LWR) were calculated. Sensitivity and specificity of LNR and LWR were estimated to determine a cut off value.
7.86% of MS-plaques were enhanced in T1 contrast-enhanced MRI. 2.4% showed DWI restriction. 0.77% showed both diffusion-restriction and T1 contrast-enhancement, 1.63% indicated diffusion-restriction but no contrast-enhancement and 7.09% showed contrast-enhancement but no diffusion-restriction. Among diffusion-restricted plaques, 32% were enhanced in T1-weighted post-contrast enhanced images and it should be noted that diffusion-restriction was seen in 9.76% of enhanced plaques. The sensitivity and specificity of the DWI restriction and its effectiveness in detecting active-plaques were calculated as 12.31% and 98.26%, respectively. The accuracy of this method in detecting the active MS-plaques estimated as 92.91%. The cut-off value for LWR and LNR was between 0.9-1 and 24-28.
By calculating LNR and LWR, the FLAIR images can be evaluated to detect new MS-plaques. LWR had higher sensitivity and specificity in comparison to LNR so it is a better index in the detection of active-plaques. Although post contrast T1 is the gold standard for evaluating active plaques, in the case of a contraindication to gadolinium, DWI can offer supplemental information on the diffusion restriction of MS plaques in a non-contrast protocol.
最常见的脱髓鞘疾病之一是多发性硬化症（MS），它可导致患者广泛残疾。活跃病变的出现可能是疾病进展的重要标志。本研究评估了弥散加权成像（DWI）信号受限、对比增强与脱髓鞘斑块信号之间的相关性。
本研究纳入了 34 名有 1043 个 MS 斑块的急性发作 MS 患者。比较了 FLAIR、DWI 和对比增强 T1 加权的 3 种 MRI 脉冲序列。利用 FLAIR 图像中 MS 病变和正常脑组织的信号强度，计算了病变/噪声比（LNR）和病变/白质比（LWR）。为了确定截断值，评估了 LNR 和 LWR 的敏感性和特异性。
在 T1 对比增强 MRI 中，7.86%的 MS 斑块增强，2.4%的 MS 斑块出现 DWI 受限，0.77%的 MS 斑块同时出现弥散受限和 T1 对比增强，1.63%的 MS 斑块出现弥散受限但无对比增强，7.09%的 MS 斑块出现对比增强但无弥散受限。在弥散受限的斑块中，32%在 T1 加权对比增强后图像中增强，值得注意的是，9.76%的增强斑块存在弥散受限。DWI 受限及其检测活跃斑块的有效性的敏感性和特异性分别计算为 12.31%和 98.26%。该方法检测活跃 MS 斑块的准确性估计为 92.91%。LWR 和 LNR 的截断值在 0.9-1 和 24-28 之间。
通过计算 LNR 和 LWR，可以评估 FLAIR 图像以检测新的 MS 斑块。与 LNR 相比，LWR 的敏感性和特异性更高，因此它是检测活跃斑块的更好指标。虽然 T1 对比增强是评估活跃斑块的金标准，但在对钆有禁忌症的情况下，DWI 可以在非对比方案中提供 MS 斑块弥散受限的补充信息。
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