Abstract:

Objective  Use T₂ mapping to evaluate the fatty infiltration of thigh muscles in Duchenne muscular dystrophy (DMD) patients, so as to analyze the value of T₂ mapping and T₂ relaxation time in the diagnosis of DMD.  Methods  Sixteen DMD patients who were admitted from January 2004 to January 2013 in our hospital and were diagnosed by clinical confirmation and gene detection have participated into this study. These 16 male patients formed the DMD group. Six age- and sex-matched healthy boys were selected as control group. Clinical functional scale, thigh axial T₁WI-turbo spin echo (TSE), T₂WI-TSE, spectral attenuated inversion recovery (SPAIR)-T₂WI and T₂ mapping were performed in both 2 groups. T₁WI fatty infiltration scale and T₂ relaxation time were assessed in adductor magnus, gracilis, adductor longus, sartorius, rectus femoris, vastus intermedius, vastus medialis, vastus lateralis, biceps femoris, semitendinosus and semimembranosus. Spearman rank correlation was conducted to assess the correlation between T₂ relaxation time and T₁WI fatty infiltration scale or clinical functional scale.  Results  Compared with control group, the T₂ relaxation time of 8 muscles (adductor magnus, adductor longus, rectus femoris, vastus intermedius, vastus medialis, vastus lateralis, biceps femoris and semimembranosus) in DMD group were prolonged (P < 0.05, for all). The longest average T₂ relaxation time was found in adductor magnus. The T₂ relaxation time of adductor magnus, vastus intermedius, vastus lateralis, biceps femoris, rectus femoris, adductor longus and vastus medialis was positively correlated with T₁WI fatty infiltration scale (P < 0.05, for all), and the T₂ relaxation time of adductor magnus and semimembranosus was positively correlated with clinical funetional scale (P < 0.05, for all). A positive correlation was found in adductor magnus between T₂ relaxation time and both T1WI fatty infiltration scale (r_s = 0.867, P = 0.000) and clinical functional scale (r_s = 0.651, P = 0.005).  Conclusions  T₂ relaxation time could be used in the quantitative and objective analysis of DMD clinical severity, and adductor magnus was considered to be the most valuable muscle to reflect the clinical severity of DMD.

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摘要：

目的 采用T₂ mapping 成像测定Duchenne 型肌营养不良症患儿大腿肌肉T₂ 弛豫时间，以评价T₂ mapping 成像在Duchenne 型肌营养不良症诊断中的价值。方法 共16 例Duchenne 型肌营养不良症患儿，均行临床严重程度分级，常规MRI（横断面T₁WI、T₂WI、频谱衰减反转恢复序列-T₂WI脂肪抑制像）行大腿肌肉T₁WI脂肪浸润分级，T₂ mapping 成像测定T₂弛豫时间。Spearman 秩相关分析评价T₂弛豫时间与T₁WI脂肪浸润程度和临床严重程度的相关性。结果 与正常对照者相比，Duchenne 型肌营养不良症患儿大收肌、长收肌、股直肌、股中间肌、股内侧肌、股外侧肌、股二头肌和半膜肌共8 块肌肉T2 弛豫时间延长（均P < 0.05），其中大收肌、股中间肌、股外侧肌、股二头肌、股直肌、长收肌和股内侧肌T₂ 弛豫时间与T₁WI 脂肪浸润程度呈正相关（均P < 0.05），大收肌和半膜肌T₂ 弛豫时间与临床严重程度呈正相关（均P < 0.05）；T₂ 弛豫时间与T₁WI 脂肪浸润程度和临床严重程度均呈正相关者仅大收肌（r_s = 0.867，P = 0.000；r_s = 0.651，P = 0.005）。结论 T₂ 弛豫时间测定可用于量化和客观分析Duchenne 型肌营养不良症的严重程度，大收肌是反映临床严重程度的最理想肌肉。

关键词: 肌营养不良, 杜氏, 腿, 磁共振成像