title: Skeletal muscle imaging in facioscapulohumeral muscular dystrophy, pattern and asymmetry of individual muscle involvement.
abstract: To better understand postural and movement disabilities, the pattern of total body muscle fat infiltration was analyzed in a large group of patients with facioscapulohumeral muscular dystrophy. Additionally, we studied whether residual D4Z4 repeat array length adjusted for age and gender could predict the degree of muscle involvement. Total body computed tomography scans of 70 patients were used to assess the degree of fat infiltration of 42 muscles from neck to ankle level on a semi-quantitative scale. Groups of muscles that highly correlated regarding fat infiltration were identified using factor analysis. Linear regression analysis was performed using muscle fat infiltration as the dependent variable and D4Z4 repeat length and age as independent variables. A pattern of muscle fat infiltration in facioscapulohumeral muscular dystrophy could be constructed. Trunk muscles were most frequently affected. Of these, back extensors were more frequently affected than previously reported. Asymmetry in muscle involvement was seen in 45% of the muscles that were infiltrated with fat. The right-sided upper extremity showed significantly higher scores for fat infiltration compared to the left side, which could not be explained by handedness. It was possible to explain 29% of the fat infiltration based on D4Z4 repeat length, corrected for age and gender. Based on our results we conclude that frequent involvement of fat infiltration in back extensors, in addition to the abdominal muscles, emphasizes the extent of trunk involvement, which may have a profound impact on postural control even in otherwise mildly affected patients.
authors.affiliation: Department of Rehabilitation, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: N H M
authors.initials: NH
authors.lastname: Rijken
authors.affiliation: Department of Neurology, Medical Centre Leeuwarden, Leeuwarden, The Netherlands.
authors.forename: E L
authors.initials: EL
authors.lastname: van der Kooi
authors.affiliation: Department for Health Evidence, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: J C M
authors.initials: JC
authors.lastname: Hendriks
authors.affiliation: Department of Neurology, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: R J G P
authors.initials: RJ
authors.lastname: van Asseldonk
authors.affiliation: Department of Neurology, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: G W
authors.initials: GW
authors.lastname: Padberg
authors.affiliation: Department of Rehabilitation, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: A C H
authors.initials: AC
authors.lastname: Geurts
authors.affiliation: Department of Neurology, Radboud University Medical Center, Nijmegen, The Netherlands. Electronic address: Baziel.vanEngelen@radboudumc.nl.
authors.forename: B G M
authors.initials: BG
authors.lastname: van Engelen
mesh_terms: D000273:Adipose Tissue / Q000000981:diagnostic imaging; D000328:Adult; D000367:Age Factors; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging* / Q000503:physiopathology; D020391:Muscular Dystrophy, Facioscapulohumeral / Q000000981:diagnostic imaging* / Q000235:genetics / Q000503:physiopathology; D012737:Sex Factors; D014057:Tomography, X-Ray Computed; D051598:Whole Body Imaging
keywords: Computer tomography; FSHD; Fatty infiltration; Muscle imaging; Neuromuscular disorders