Paoletti M, Monforte M, Barzaghi L, Tasca G, Bergsland N, Faggioli A, Solazzo F, Manco G, Bortolani S, Torchia E, Ravera B, Deligianni X, Santini F, Ballante E, Figini S, Tartaglione T, Ricci E, Pichiecchio A
Advanced Imaging and Artificial Intelligence, Neuroradiology Department, IRCCS Mondino Foundation, Pavia, Italy.
Dipartimento di Neuroscienze, Organi di Senso e Torace, UOC di Neurologia, Fondazione Policlinico Universitario A. Gemelli IRCCS, Largo Agostino Gemelli, 8, 00168, Rome, Italy.
J Neurol. 2025 Apr 2;272(4):306. doi: 10.1007/s00415-025-13062-8.
Facioscapulohumeral muscular dystrophy (FSHD) is a genetic disorder characterized by progressive skeletal muscle wasting. Longitudinal muscle magnetic resonance imaging (MRI) studies demonstrated that the risk of developing irreversible fatty replacement is higher in muscles showing edematous lesions. The quantification of this phenomenon is an understudied topic in FSHD and intramuscular water content can also represent a potential biomarker sensitive to the effect of investigational drugs. We applied a multiparametric quantitative muscle MRI protocol to assess disease progression quantifying fatty replacement and muscle edema over 2 years, using fat fraction (FF) and water-T2 (wT2) metrics.
Thirty FSHD patients with at least one muscle showing signs of edema on conventional MRI were enrolled. FF and wT2 maps were assessed in 12 thigh and 6 leg muscles for each side, and a linear mixed model was employed to explore their variations over time. The measurements were acquired at baseline, 12, and 24 months. Quantitative MRI parameters were also correlated with clinical scales and functional assessments collected at baseline.
The average yearly increase in FF was 2 ± 0.6% at thigh level and 1.9 ± 0.7% at leg level. No significant longitudinal changes in wT2 were observed. Muscles with intermediate FF (15-30%) at baseline and those with baseline wT2 values above 41 ms showed the highest increase in fat replacement. Both FF and wT2 showed significant correlations with clinical scales and functional assessments.
Our longitudinal study identified muscles and compartments more likely to show FF increase in FSHD subjects. Multiparametric quantitative MRI metrics should be incorporated into clinical trial frameworks to explore their potential in detecting early therapeutic effects.
面肩肱型肌营养不良症（FSHD）是一种以进行性骨骼肌萎缩为特征的遗传性疾病。纵向肌肉磁共振成像（MRI）研究表明，在出现水肿性病变的肌肉中，发生不可逆脂肪替代的风险更高。在FSHD中，对这一现象的量化是一个研究较少的课题，肌肉内含水量也可能是一种对研究药物效果敏感的潜在生物标志物。我们应用多参数定量肌肉MRI方案，通过脂肪分数（FF）和水T2（wT2）指标，在2年时间里评估疾病进展，量化脂肪替代和肌肉水肿。
招募了30例FSHD患者，这些患者至少有一块肌肉在传统MRI上显示出水肿迹象。对每侧的12块大腿肌肉和6块小腿肌肉进行FF和wT2图谱评估，并采用线性混合模型来探讨它们随时间的变化。测量在基线、12个月和24个月时进行。定量MRI参数还与基线时收集的临床量表和功能评估进行了关联。
大腿水平FF的年均增加率为2±0.6%，小腿水平为1.9±0.7%。未观察到wT2有显著的纵向变化。基线时FF中等（15 - 30%）的肌肉以及基线wT2值高于41毫秒的肌肉，脂肪替代增加最多。FF和wT2均与临床量表和功能评估显著相关。
我们的纵向研究确定了FSHD患者中更可能出现FF增加的肌肉和部位。多参数定量MRI指标应纳入临床试验框架，以探索其在检测早期治疗效果方面的潜力。
