Characteristics of fatty infiltration and edema of muscle MRI in Duchenne muscular dystrophy patients

Abstract

Objective To summarize the characteristics of fatty infiltration and edema of muscle MRI in Duchenne muscular dystrophy (DMD) patients. Methods A total of 70 DMD patients underwent Clinical Functional Scale and muscle MRI of the pelvic (gluteus maximus, gluteus medius, gluteus minimus, iliopsoas, piriformis, obturator internus, obturator externus, tensor fasciae latae, pectineus, erector spinae, psoas major muscle, iliacus), thigh (adductor magnus, gracilis, adductor longus, sartorius, rectus femoris, vastus intermedius, vastus medialis, vastus lateralis, biceps femoris, semitendinosus, semimembranosus) and leg (gastrocnemius, soleus, peroneus longus, tibialis posterior, tibialis anterior, flexor hallucis longus, extensor hallucis longus, extensor digitorum longus). T₁WI fatty infiltration grade and fat suppression T₂WI edema grade were performed to analyze the imaging features of fatty infiltration and edema. Results In 31 muscles, 30 muscles (96.77% ) presented fatty infiltration and 23 (74.19% ) presented edema. The occurrence rate of fatty infiltration was higher than that of edema. A total of 21 muscles including gluteus maximus, were found T₁WI fatty infiltration grades greater than 2, and 10 muscles including tibialis posterior, were less than 1. Five muscles including soleus were found fat suppression T₂WI edema grade 3. Spearman rank correlation analysis showed positive correlations between T₁WI fatty infiltration grade and Clinical Functional Scale in 7 pelvic muscles [gluteus maximus (r_s = 0.518, P = 0.016), gluteus medius (r_s = 0.528, P = 0.014), gluteus minimus (r_s = 0.528, P = 0.014), iliopsoas (r_s = 0.695, P = 0.000), piriformis (r_s = 0.451, P = 0.040), pectineus (r_s = 0.567, P = 0.009), erector spinae (r_s = 0.499, P = 0.025)], 7 thigh muscles [adductor magnus (r_s = 0.607, P = 0.005), adductor longus (r_s = 0.547, P = 0.013), rectus femoris (r_s = 0.614, P = 0.004), vastus intermedius (r_s = 0.566, P = 0.009), vastus medialis (r_s = 0.522, P = 0.018), vastus lateralis (r_s = 0.503, P = 0.024), biceps femoris (r_s = 0.508, P = 0.022)] and 3 leg muscles [gastrocnemius (r_s = 0.715, P = 0.001), peroneus longus (r_s = 0.571, P = 0.017), tibialis posterior (r_s = 0.514, P = 0.035)]. There was no correlation between T₁WI fatty infiltration grade and Clinical Functional Scale in other muscles (P > 0.05, for all). There was no correlation between fat suppression T₂WI edema grade and Clinical Functional Scale in all muscles (P > 0.05, for all). Conclusions Fatty infiltration grade can be well used to assess the severity of DMD. The role of muscle edema on assessing clinical severity should be analyzed according to individual muscle characteristics.

DOI: 10.3969/j.issn.1672-6731.2018.07.006