研究发现，全身 MRI 提高 ALS 诊断确定性

Assessing muscle swelling from scans improves accuracy

通过扫描评估肌肉肿胀可提高准确性

Incorporating muscle assessments from whole-body MRIs (WB-MRIs) into the diagnostic process for amyotrophic lateral sclerosis (ALS) may help identify the condition with a greater degree of certainty, according to a study from France.

法国一项研究显示，将全身 MRI（WB-MRI）的肌肉评估纳入肌萎缩侧索硬化症（ALS）的诊断流程，可能有助于以更高的确定性识别这种疾病。

ALS causes damage to specialized nerve cells called motor neurons. Some criteria for diagnosing ALS require signs of problems with the motor neurons that run from the brain to the spinal cord (upper motor neurons, or UMNs) and those that run from the spinal cord to muscles (lower motor neurons, or LMNs). However, it can be difficult to identify LMN involvement with common diagnostic techniques, reducing the certainty of diagnosis.

ALS 会损伤被称为运动神经元的特殊神经细胞。一些 ALS 诊断标准要求存在从大脑延伸至脊髓的运动神经元（上运动神经元，或 UMN）以及从脊髓延伸至肌肉的运动神经元（下运动神经元，或 LMN）出现问题的迹象。然而，使用常见诊断技术可能难以识别 LMN 受累，从而降低诊断的确定性。

The researchers found that assessing muscle swelling (edema) on WB-MRI can improve the detection of LMN dysfunction and increase the certainty of an ALS diagnosis.

研究人员发现，在 WB-MRI 上评估肌肉肿胀（水肿）可改善对 LMN 功能障碍的检测，并提高 ALS 诊断的确定性。

“These findings suggest that muscle edema may represent a relevant surrogate marker of LMN involvement for integration into MRI-based diagnostic assessment of ALS,” they wrote.

他们写道：“这些发现提示，肌肉水肿可能代表一种与 LMN 受累相关的替代标志物，可纳入基于 MRI 的 ALS 诊断评估。”

The study, “ Whole-body muscle MRI improves diagnostic certainty in amyotrophic lateral sclerosis ,” was published in Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration .

这项题为“全身肌肉 MRI 提高肌萎缩侧索硬化症的诊断确定性”的研究发表于 Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration。

Diagnosing ALS is often complex because there is no definitive biological marker of the condition. One commonly used diagnostic framework is the Awaji criteria, which classify a case as possible, probable, or definite ALS depending on the amount of evidence. This includes evidence of UMN and LMN dysfunction.

ALS 的诊断通常很复杂，因为目前没有这种疾病的确定性生物标志物。一个常用的诊断框架是 Awaji 标准，该标准根据证据量将病例分类为可能、很可能或明确 ALS。这包括 UMN 和 LMN 功能障碍的证据。

The main method for testing LMN dysfunction is electromyography (EMG), which measures the electrical activity of muscles at rest and with movement. Because the technique is invasive, only a limited number of muscles are assessed, potentially underestimating LMN involvement.

检测 LMN 功能障碍的主要方法是肌电图（EMG），它测量肌肉在静息和运动时的电活动。由于该技术具有侵入性，因此只评估有限数量的肌肉，可能低估 LMN 受累。

WB-MRI may provide an alternate method for assessing LMN dysfunction. Unlike EMG, which requires separate testing for each muscle, WB-MRI captures data from muscles throughout the body.

WB-MRI 可能提供一种评估 LMN 功能障碍的替代方法。与需要对每块肌肉分别进行检测的 EMG 不同，WB-MRI 可采集全身各处肌肉的数据。

The researchers set out to test whether adding WB-MRI to the diagnostic workup improved the diagnostic certainty in 47 people with suspected ALS.

研究人员着手测试，在 47 名疑似 ALS 患者的诊断检查中加入 WB-MRI 是否能提高诊断确定性。

When using only information from a neurological examination and EMG, the team classified 51.1% of cases as possible ALS, 40.4% as probable ALS, and 8.5% as definite ALS based on the Awaji criteria. Over two years of follow-up, no alternative diagnoses emerged for any participants, supporting the ALS diagnosis.

当仅使用神经系统检查和 EMG 信息时，团队根据 Awaji 标准将 51.1% 的病例分类为可能 ALS，40.4% 分类为很可能 ALS，8.5% 分类为明确 ALS。在两年的随访中，任何参与者均未出现其他诊断，这支持了 ALS 诊断。

Next, the researchers used WB-MRI data to complement clinical assessments and EMG and repeated the classification process. They considered muscle edema (swelling due to fluid buildup) and fatty infiltration (replacement of muscle cells with fat cells) signs of potential LMN dysfunction.

随后，研究人员使用 WB-MRI 数据补充临床评估和 EMG，并重复分类流程。他们将肌肉水肿（因液体积聚导致的肿胀）和脂肪浸润（肌肉细胞被脂肪细胞替代）视为潜在 LMN 功能障碍的迹象。

When edema and fatty infiltration were both required as evidence of LMN problems, the diagnostic certainty increased for about 15% of participants. This included possible cases redefined as probable or definite and probable cases redefined as definite.

当水肿和脂肪浸润都被要求作为 LMN 问题的证据时，约 15% 参与者的诊断确定性提高。这包括可能病例被重新定义为很可能或明确，以及很可能病例被重新定义为明确。

When only muscle edema was considered, the diagnostic certainty increased for about one-quarter of cases. After this reclassification, 17% of participants had a definite ALS diagnosis.

当仅考虑肌肉水肿时，约四分之一病例的诊断确定性提高。此次重新分类后，17% 的参与者获得明确 ALS 诊断。

“The addition of MRI findings as a surrogate marker of LMN involvement resulted in a shift toward higher diagnostic categories,” they wrote.

他们写道：“将 MRI 发现作为 LMN 受累的替代标志物加入后，诊断类别向更高确定性转移。”

Additional analyses showed that edema tended to correlate with signs of LMN problems on EMG. However, it also identified areas of potential LMN dysfunction that EMG did not catch, suggesting that swelling may reflect early patterns of nerve loss in ALS.

进一步分析显示，水肿往往与 EMG 上 LMN 问题的迹象相关。然而，它也识别出 EMG 未能发现的潜在 LMN 功能障碍区域，提示肿胀可能反映 ALS 中早期神经丧失模式。

In contrast, fatty infiltration had low correlations with EMG findings. This could reflect more advanced muscle involvement, according to the team.

相比之下，脂肪浸润与 EMG 发现的相关性较低。团队表示，这可能反映更晚期的肌肉受累。

Based on these findings, they concluded that muscle edema is likely a more useful metric in the ALS diagnostic process.

基于这些发现，他们得出结论，肌肉水肿很可能是 ALS 诊断流程中更有用的指标。

The study had several limitations. For example, WB-MRI analyses relied on clinician judgment rather than quantitative metrics, which could influence results. And while edema could be a marker of LMN dysfunction, it isn’t necessarily specific to ALS.

该研究存在若干局限性。例如，WB-MRI 分析依赖临床医生判断，而非定量指标，这可能影响结果。此外，尽管水肿可能是 LMN 功能障碍的标志物，但它并不一定对 ALS 具有特异性。

“Muscle edema should be interpreted cautiously and within the appropriate clinical and electrophysiological context rather than as evidence of disease specificity,” the researchers wrote.

研究人员写道：“应谨慎解读肌肉水肿，并将其置于适当的临床和电生理背景中，而不是将其视为疾病特异性的证据。”

The scientists recommended that future studies attempt to replicate these findings in larger groups of participants from more clinical centers. Further research could also help determine if WB-MRI provides useful information for monitoring ALS progression or predicting prognosis, they said.

科学家建议，未来研究应尝试在来自更多临床中心、更大规模的参与者群体中重复这些发现。他们表示，进一步研究还可帮助确定 WB-MRI 是否能为监测 ALS 进展或预测预后提供有用信息。