“Target” and “Sandwich” Signs in Thigh Muscles have High Diagnostic Values for Collagen VI-related Myopathies

• Published in: Chinese medical journal Vol. 129; no. 15; pp. 1811 - 1816
• Main Authors: Fu, Jun, Zheng, Yi-Ming, Jin, Su-Qin, Yi, Jun-Fei, Liu, Xiu-Juan, Lyn, He, Wang, Zhao-Xia, Zhang, Wei, Xiao, Jiang-Xi, Yuan, Yun
• Format: Journal Article
• Language: English
• Published: China Wolters Kluwer - Medknow Publications 05.08.2016; Medknow Publications and Media Pvt. Ltd; Lippincott Williams & Wilkins Ovid Technologies; Department of Neurology, Peking University First Hospital, Beijing 100034, China; Medknow Publications & Media Pvt Ltd; Wolters Kluwer
• Subjects: Adolescent; Adult; Child; Child, Preschool; Collagen Type VI - genetics; Collagen Type VI - metabolism; Collagen VI-related Myopathies; Gene Mutation; Muscle Magnetic Resonance Imaging; Sensitivity; Specificity; Diagnosis; Female; Humans; Infant; Infant, Newborn; Magnetic Resonance Imaging; Male; Muscle, Skeletal - pathology; Muscular diseases; Muscular Diseases - genetics; Muscular Diseases - metabolism; Muscular Diseases - pathology; Mutation - genetics; Original; Risk factors; Sensitivity and Specificity; Thigh - pathology; Thigh muscles; Young Adult; 三明治; 基因突变; 肌病; 肌肉疾病; 肌肉脂肪; 胶原蛋白; 诊断价值; Collagen Ⅵ-related Myopathies; Gene Mutation; Sensitivity; Specificity; Muscle Magnetic Resonance Imaging
• ISSN: 0366-6999; 2542-5641
• DOI: 10.4103/0366-6999.186638

Background： Collagen Vl-related myopathies are autosomal dominant and recessive hereditary myopathies, mainly including Ullrich congenital muscular dystrophy （UCMD） and Bethlem myopathy （BM）. Muscle magnetic resonance imaging （MRI） has been widely used to diagnosis muscular disorders. The purpose of this study was to evaluate the diagnostic value of thigh muscles MRI for collagen VI-related myopathies. Methods： Eleven patients with collagen VI gene mutation-related myopathies were enrolled in this study. MRI of the thigh muscles was performed in all patients with collagen VI gene mutation-related myopathies and in 361 patients with other neuromuscular disorders （disease controls）. Tl-weighted images were used to assess fatty infiltration of the muscles using a modified Mercuri＇s scale. We assessed the sensitivity and specificity of the MRI features of collagen Vl-related myopathies. The relationship between fatty infiltration of muscles and specific collagen VI gene mutations was also investigated. Results： Eleven patients with collagen VI gene mutation-related rnyopathies included six UCMD patients and five BM patients. There was no significant difference between UCMD and BM patients in the fatty infiltration of each thigh muscle except sartorius （P = 0.033）： theretbre, we combined the UCMD and BM data. Mean fatty infiltration scores were 3.1 and 3.0 in adductor magnus and gluteus maximus, while the scores were 1.3, 1.3, and 1.5 in gracilis, adductor longus, and sartorius, respectively. A “target” sign in rectus femoris （RF） was present in seven cases, and a “sandwich” sign in vastus lateralis （VL） was present in ten cases. The “target” and “sandwich” signs had sensitivities of 63.6% and 90.9% and specificities of 97.3% and 96,9% for the diagnosis of collagen Vl-related myopathies, respectively. Fatty infiltration scores were 2.0-3.0 in seven patients with mutations in the triple-helical domain, and 1.0-1.5 in three of four patients with mutations in the N- or C-domain of the collagen VI genes. Conclusions： The “target” sign in RF and “sandwich” sign in VL are common MRI features and are useful for the diagnosis of collagen VI-related myopathies. The severity of fatty infiltration of muscles may have a relationship with the mutation location of collagen VI gene.