流入血管空间MRI评估皮肌炎患者肌肉小动脉血容量

Inflow-based vascular-space-occupancy MRI for evaluation of arteriolar muscular blood volume in dermatomyositis patients

目的探讨流入血管空间(iVASO)-MRI测量肌肉小动脉血容量(MBVa)的可重复性和对皮肌炎患者的潜在临床价值。方法前瞻性连续收集南方医科大学南方医院自2018年12月至2019年4月的15例皮肌炎患者,并同期纳入15例正常志愿者,采用3.0 T MR扫描系统进行大腿T1WI、短时反转恢复(STIR)T2WI和iVASO-MRI扫描,根据T1WI、STIR T2WI表现,将大腿肌肉分为正常肌肉、未受累肌肉、水肿肌肉和萎缩或脂肪浸润肌肉,由两名医师基于iVASO-MRI数据独立测量最大MBVa(MBVamax)和平均MBVa(MBVamean)。为评估iVASO的可重复性,随机抽取17名受试者(12名健康志愿者和5名皮肌炎患者)3 d后再次进行扫描并由同1名医师测量MBVa值,计算组内相关系数(ICC)。采用Kruskal-WallisH检验比较不同类型肌肉的MBVamax和MBVamean差异,两两比较采用Mann-Whitney U检验。结果观察者间MBVamax和MBVamean的ICC分别是0.95和0.96。重复扫描MBVamax和MBVamean的ICC分别为0.87和0.89。正常肌肉、未受累肌肉、水肿肌肉及萎缩或脂肪浸润肌肉间MBVamax和MBVamean总体差异有统计学意义(P<0.001)。不同类型肌肉间MBVamax和MBVamean两两比较结果显示,与正常肌肉相比,未受累肌肉、水肿肌肉及萎缩或脂肪浸润肌肉均显著降低(P<0.05);未受累肌肉与水肿肌肉间MBVamax和MBVamean差异均无统计学意义(P值均为0.99),二者均高于萎缩或脂肪浸润肌肉(P<0.05)。结论iVASO-MRI技术可以可靠地评估大腿肌肉的MBVa,对诊断皮肌炎具有潜在临床价值。

Objective To investigate the reproducibility of inflow-based vascular-space-occupancy(iVASO)-MRI in quantifying skeletal muscle perfusion and its potential clinical value in patients with dermatomyositis(DM).Methods Totally 15 consecutive patients with DM and 15 healthy volunteers were enrolled in this prospective study from December 2018 to April 2019 at Nanfang Hospital,Southern Medical University.All subjects underwent T1WI,short-tau inversion recovery(STIR)T2WI,and iVASO-MRI of thigh on a 3.0 T MR scanner.According to findings on T1WI and STIR T2WI,the muscles were divided into normal,unaffected,edematous and atrophic or fat-infiltrated groups.Maximum arteriolar muscular blood volume(MBVa_max)and mean MBVa(MBVa_mean)of these 4 groups of muscles were obtained by 2 radiologists independently.In order to evaluate the reproducibility of iVASO,the repeated scan was performed 3 days later in 17 subjects(12 healthy volunteers and 5 DM patients),and the MBVa values were measured to calculate the intraclass correlation coefficients(ICC).The MBVa_max and MBVa_mean among the 4 groups were compared by using Kruskal-Wallis H test and the differences of each 2 groups was compare by using Mann-Whitney U test.Results The ICC between the 2 observers was 0.95 and 0.96 for MBVa_max and MBVa_mean,respectively.The ICC between repeated tests was 0.87 and 0.89 for MBVa_max and MBVa_mean,respectively.There was significant difference among normal muscles,unaffected muscles,edematous muscles and atrophic or fat-infiltrated muscles(P<0.001).Post hoc comparisons of MBVa_max and MBVa_mean showed that compared to normal muscles,unaffected muscles,edematous muscles and atrophic or fat-infiltrated muscles had a significant decrease of MBVa(P<0.05).Unaffected muscles and edematous muscles showed no significant difference in terms of MBVa_max and MBVa_mean(both P=0.99),which were significantly higher than those of atrophic or fat-infiltrated muscles(P<0.05).Conclusions iVASO-MRIcan reliably quantify the MBVa of thigh muscular arteriolar,and it is potentially valuable in the diagnosis of DM.