目的:尚未对面肩肱型肌营养不良症(FSHD)进行肌肉扩散张量成像研究。我们评估了FSHD受试者与健康对照(HC)相比的扩散率参数,关于它们在任何脂肪替代或水肿之前的能力。
方法:脂肪分数(FF),水T2(wT2),意思是,径向,轴向扩散系数(MD,RD,AD),计算了10名FSHD受试者和15名HC的大腿肌肉各向异性分数(FA)。比较FSHD和对照组的所有参数,也探索它们沿着肌肉主轴的梯度。在亚组分析中测试了扩散率参数,作为具有不同FF和wT2程度的肌肉区室疾病受累的预测因子,并且还与临床严重程度评分相关。
结果:我们发现MD,RD,FSHD受试者的AD显著低于对照组,而我们未能发现FA的差异。相比之下,我们发现FF和FA之间存在显著正相关,MD之间存在负相关,RD,AD和FF。与wT2没有发现相关性。在我们的亚组分析中,我们发现与对照组相比,没有明显脂肪替代或水肿的肌肉区室(FF<10%,wT2<41ms)显示出降低的AD和FA。较少涉及的隔室比更多涉及的隔室显示出不同的扩散率参数。
结论:我们的探索性研究能够证明即使在没有明显脂肪替代或水肿的肌肉中也存在扩散参数异常。需要更大的队列来确认这些初步发现。
OBJECTIVE: Muscle diffusion tensor imaging has not yet been explored in facioscapulohumeral muscular dystrophy (FSHD). We assessed diffusivity parameters in FSHD subjects compared with healthy controls (HCs), with regard to their ability to precede any fat replacement or edema.
METHODS: Fat fraction (FF), water T2 (wT2), mean, radial, axial diffusivity (MD, RD, AD), and fractional anisotropy (FA) of thigh muscles were calculated in 10 FSHD subjects and 15 HCs. All parameters were compared between FSHD and controls, also exploring their gradient along the main axis of the muscle. Diffusivity parameters were tested in a subgroup analysis as predictors of disease involvement in muscle compartments with different degrees of FF and wT2 and were also correlated with clinical severity scores.
RESULTS: We found that MD, RD, and AD were significantly lower in FSHD subjects than in controls, whereas we failed to find a difference for FA. In contrast, we found a significant positive correlation between FF and FA and a negative correlation between MD, RD, and AD and FF. No correlation was found with wT2. In our subgroup analysis we found that muscle compartments with no significant fat replacement or edema (FF < 10% and wT2 < 41 ms) showed a reduced AD and FA compared with controls. Less involved compartments showed different diffusivity parameters than more involved compartments.
CONCLUSIONS: Our exploratory study was able to demonstrate diffusivity parameter abnormalities even in muscles with no significant fat replacement or edema. Larger cohorts are needed to confirm these preliminary findings.