Paramagnetic Rim Lesions in Multiple Sclerosis: Comparison of Visualization at 1.5-T and 3-T MRI.
Paramagnetic Rim Lesions in Multiple Sclerosis: Comparison of Visualization at 1.5-T and 3-T MRI.
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多发性硬化症的顺磁边缘病变：1.5-T和3-T磁共振成像的可视化比较。
DOI：
10.2214/ajr.21.26777
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发表时间：
2022-07
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多发性硬化症（MS）的特征是急性和慢性鞘内炎症。MS病变的一个子集在磁共振成像序列上显示顺磁性边缘，反映了小胶质细胞中的铁积累。这些顺磁边缘病变已被提出作为一个标志的区室化阴燃病。顺磁边缘病变已显示在7 T，最近，在3 T。由于在较低场强下磁化率效应较弱，因此尚不清楚在1.5 T下是否可见顺磁边缘病变。本研究的目的是比较MS患者在1.5-T和3-T MRI下使用磁敏感加权成像的顺磁边缘病变的可视化。本回顾性研究包括9例MS患者（5例女性，4例男性;平均年龄46.8岁），这些患者使用相同制造商的可比磁敏感加权血管造影（SWAN）序列进行1.5-T和3-T MRI。对测量大于3 mm的病变进行注释。两名审查员在单独的会议中独立评估了每个场强下的图像，并将注释的病变分类为等强度、弥漫顺磁性或顺磁性边缘病变。在包括第三位评审员在内的共识会议上讨论了不确定性。使用kappa系数评估一致性。基于3-T一致读数，140个注释病灶中的115个（82%）为等信号病灶，16个（11%）为弥漫性顺磁性病灶，9个（6%）为顺磁性边缘病灶;基于1.5-T一致读数，115例（82%）为等信号病变，14例（10%）为弥漫性顺磁性病变，11例（8%）为顺磁性边缘病变。顺磁性边缘病变的平均病变直径为11.9 mm，弥漫性顺磁性病变为6.4 mm（p = 0.006），等信号病变为7.8 mm（p = 0.003）。在1.5 T（κ = 0.65）和3 T（κ = 0.70）下，评估者将病变分类为顺磁性边缘病变的一致性很高。在两种场强下的共识读数之间，顺磁边缘病变的一致性也很高（κ = 0.79）。我们发现，在1.5 T和3 T MRI下，顺磁边缘病变的识别具有可比性，两种场强下的评估者间一致性和场强之间的一致性。顺磁性边缘病变可能是MS慢性神经炎症的一个新兴标志物。它们在1.5 T下的可见性支持顺磁性边缘病变识别在更广泛的临床环境中的转化潜力，其中1.5 T扫描仪是普遍的。
Multiple sclerosis (MS) is characterized by both acute and chronic intrathecal inflammation. A subset of MS lesions show paramagnetic rims on susceptibility-weighted MRI sequences, reflecting iron accumulation in microglia. These paramagnetic rim lesions have been proposed as a marker of compartmentalized smoldering disease. Paramagnetic rim lesions have been shown at 7 T and, more recently, at 3 T. As susceptibility effects are weaker at lower field strength, it remains unclear if paramagnetic rim lesions are visible at 1.5 T. The purpose of our study was to compare visualization of paramagnetic rim lesions using susceptibility-weighted imaging at 1.5-T and 3-T MRI in patients with MS. This retrospective study included nine patients (five women, four men; mean age, 46.8 years) with MS who underwent both 1.5-T and 3-T MRI using a comparable susceptibility-weighted angiography (SWAN) sequence from the same manufacturer. Lesions measuring greater than 3 mm were annotated. Two reviewers independently assessed images at each field strength in separate sessions and classified the annotated lesions as isointense, diffusely paramagnetic, or paramagnetic rim lesions. Discrepancies were discussed at consensus sessions including a third reviewer. Agreement was assessed using kappa coefficients. Based on the 3-T consensus readings, 115 of 140 annotated lesions (82%) were isointense lesions, 16 (11%) were diffusely paramagnetic lesions, and nine (6%) were paramagnetic rim lesions; based on the 1.5-T consensus readings, 115 (82%) were isointense lesions, 14 (10%) were diffusely paramagnetic lesions, and 11 (8%) were paramagnetic rim lesions. The mean lesion diameter was 11.9 mm for paramagnetic rim lesions versus 6.4 mm for diffusely paramagnetic lesions (p = .006) and 7.8 mm for isointense lesions (p = .003). Interrater agreement for lesion classification as a paramagnetic rim lesion was substantial at 1.5 T (κ = 0.65) and 3 T (κ = 0.70). Agreement for paramagnetic rim lesions was also substantial between the consensus readings at the two field strengths (κ = 0.79). We show comparable identification of paramagnetic rim lesions at 1.5-T and 3-T MRI with substantial interrater agreement at both field strengths and substantial consensus agreement between the field strengths. Paramagnetic rim lesions may be an emerging marker of chronic neuroinflammation in MS. Their visibility at 1.5 T supports the translational potential of paramagnetic rim lesion identification to more widespread clinical settings, where 1.5-T scanners are prevalent.