基于IDEAL-IQ技术定量评估特发性炎症性肌病下肢肌肉脂肪浸润的研究

IDEAL-IQ Technique in the Quantitative Assessment of Muscle Fat Infiltration in Lower Limbs of Idiopathic Inflammatory Myopathies

目的利用最小二乘法估计和不对称回波迭代分解水和脂肪成像(IDEAL-IQ)序列定量评估特发性炎症性肌病(IIM患者大腿肌肉脂肪浸润程度,分析脂肪分数(FF)与临床指标的相关性。资料与方法回顾性收集2020年1月—2022年8月宁夏医科大学总医院经临床及病理证实的32例IIM患者和年龄、性别相匹配的32名健康志愿者(对照组),行双侧大腿T1WI、T2WI及IDEAL-IQ序列横轴位扫描,于IDEAL-IQ序列生成的FF图上测量双侧大腿前外侧肌群、内侧肌群及后侧肌群各组肌肉的FF值。比较IIM组与对照组间、不同肌群间肌肉FF值的差异,分析大腿肌肉FF值与IIM患者体重指数、病程、肌力的相关性。结果IIM组大腿前外侧肌群、内侧肌群及后侧肌群FF值分别为16.60±3.67、6.77±4.92、17.32±4.01,显著高于对照组各肌肉FF值(2.58±2.57、1.40±0.64、1.57±0.19),差异均有统计学意义(t=-7.29、-6.91、-4.85,P均<0.05)。IIM组大腿肌肉平均FF值与病程呈正相关(r=0.587,P<0.001),前外侧肌群、后侧肌群及内侧肌群FF值均与肌力呈负相关(r=-0.885、-0.761、-0.594,P<0.001)。结论基于IDEAL-IQ技术的FF值能量化和客观分析IIM患者大腿肌肉脂肪浸润程度,且与肌力呈负相关,FF值是监测IIM患者大腿肌肉功能障碍的影像学标志物,为临床诊断和治疗提供客观依据。

Purpose To evaluate the fatty infiltration of lower limbs by using iterative decomposition of water and fat with asymmetry and least squares estimation quantitative fat imaging(IDEAL-IQ)technique in idiopathic inflammatory myopathy(IIM)patients,and to analyze the correlation between muscle fat fraction(FF)and clinical assessments.Materials and Methods Thirty-two patients with IIM were diagnosed by muscle biopsy and 32 age-,gender-matched healthy volunteers(control group)were recruited.T1WI,T2WI in axial view and IDEAL-IQ sequence of thighs were scanned on each subject.FF values of the anterior,interior and posterior thigh muscles were measured on the FF image generated in the IDEAL-IQ sequence,and medical research council scale score of the IIM group were collected.The difference of muscle FF value between the IIM group and control group was compared,the correlation between FF value and muscle strength of thigh muscles was also analyzed.Results The mean FF values of anterior,interior and posterior thigh muscles in IIM group were 16.60±3.67,6.77±4.92 and 17.32±4.01,respectively,which were significantly higher than those in control group(2.58±2.57,1.40±0.64 and 1.57±0.19),with statistically significant differences(t=-7.29,-6.91,-4.85;all P<0.05).Spearman test showed that the mean FF value was significantly correlated with course of disease(r=0.587,P<0.001).The mean FF values of anterior,interior and posterior thigh muscles were significantly correlated with muscle strength(r=-0.885,-0.761,-0.594;all P<0.001).Conclusion The IDEAL-IQ technique can quantitatively and objectively analyze the severity of muscle fat infiltration in IIM patients,and its degree is correlated with the muscle strength,which has significant clinical application value.