title: MRI quantification of fatty infiltration and muscle atrophy in a mouse model of rotator cuff tears.
abstract: Rotator cuff pathology is the most common shoulder problem seen by orthopedic surgeons. Rotator cuff muscle fatty infiltration and muscle atrophy are common in larger tears and are considered predicting factors for the prognosis of cuff repair. Clinically, MRI is the gold standard in determining fatty infiltration and muscle atrophy; however, analysis for MRI imaging is primarily qualitative in nature with the results lacking further validation. We have recently developed a mouse model of rotator cuff tears. The goal of this study is to quantify and verify rotator cuff muscle atrophy and fatty infiltration using high-resolution MRI in our mouse model. The rotator cuff muscles were analyzed for fat using a triglyceride quantification assay (TQA), muscle volume was measured through water displacement (WD), and histology. The study revealed that MRI had a high correlation with fat as measured with histology and TQA (R(2)  =098). MRI also correlated well with atrophy measured with WD and wet weight. This suggests that MRI is a reliable modality in evaluating the progression of fatty infiltration and muscle atrophy following rotator cuff tears in a small animal model.
authors.affiliation: Department of Veterans Affairs, San Francisco Veterans Affairs Medical Center, San Francisco, California, USA.
authors.forename: Sanjum P
authors.initials: SP
authors.lastname: Samagh
authors.forename: Erik J
authors.initials: EJ
authors.lastname: Kramer
authors.forename: Gerd
authors.initials: G
authors.lastname: Melkus
authors.forename: Dominique
authors.initials: D
authors.lastname: Laron
authors.forename: Blake M
authors.initials: BM
authors.lastname: Bodendorfer
authors.forename: Kyle
authors.initials: K
authors.lastname: Natsuhara
authors.forename: Hubert T
authors.initials: HT
authors.lastname: Kim
authors.forename: Xuhui
authors.initials: X
authors.lastname: Liu
authors.forename: Brian T
authors.initials: BT
authors.lastname: Feeley
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism / Q000473:pathology*; D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D008279:Magnetic Resonance Imaging / Q000379:methods*; D051379:Mice; D008810:Mice, Inbred C57BL; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology; D009133:Muscular Atrophy / Q000473:pathology*; D009929:Organ Size; D017006:Rotator Cuff / Q000473:pathology*; D000070636:Rotator Cuff Injuries; D013708:Tendon Injuries / Q000473:pathology*; D014280:Triglycerides / Q000378:metabolism; D014867:Water / Q000378:metabolism
chemical_list: D014280:Triglycerides; D014867:Water