Quantifying skeletal muscle volume and shape in humans using MRI: A systematic review of validity and reliability
Aims The aim of this study was to report the metrological qualities of techniques currently used to quantify skeletal muscle volume and 3D shape in healthy and pathological muscles. Methods A systematic review was conducted (Prospero CRD42018082708). PubMed, Web of Science, Cochrane and Scopus databases were searched using relevant keywords and inclusion/exclusion criteria. The quality of the articles was evaluated using a customized scale. The results of this systematic review help the choice
... ew help the choice of appropriate segmentation techniques, according to the purpose of the measurement. In healthy populations, techniques that greatly simplified the process of manual segmentation yielded greater errors in volume and shape estimations. Reduction of the number of manually segmented slices was possible with appropriately chosen segmented slices or with DPSO. Other automatic techniques showed promise, but data were insufficient for their validation. More data on the metrological quality of techniques used in the cases of muscle pathology are required. Quantifying skeletal muscle volume and shape in humans using MRI: Validity and reliability PLOS ONE | https://doi. Our first hypothesis was that manual slice by slice segmentation would have good metrological properties but would need a large amount of time. The second was that while providing valid and reliable results, automatic segmentation techniques would require less time. Materials and methods This systematic review adheres to the PRISMA guidelines. A PRISMA checklist was completed (S1 Table) and the review protocol was published in Prospero (CRD42018082708). Database search and selection process Articles were identified through a comprehensive search of the following online bibliographic databases: PubMed, Web of Science, The Cochrane Library and Scopus. In order to ensure the search was exhaustive, the following Medical Subject Headings (MeSH) and keyword combinations were used (I) MRI, magnetic resonance imaging, (II) muscle, skeletal muscle, muscul � (III) (keywords relating to segmentation) volum � , cross sectional area, three dimension � , 3D, shape, segmentation, organ size and (IV) (keywords relative to metrological properties) reliability, reproducibility, repeatability, validity, accuracy, measur � , metrologic � , validation stud � . Search strings were formulated and tailored to the search syntax of each database to ensure a common search strategy (S1 Text). Neither publication year nor language limits were imposed. The last search was performed in January 2018. Inclusion criteria were: I) studies in which the main aim was to describe and/or evaluate a method to determine skeletal muscle (or functional groups) volume and/or shape using MRI data, II) the study was on human subjects and III) the study included an evaluation of the metrological qualities of the method. Studies that evaluated head and neck muscles or that evaluated muscle groups that were not functionally grouped [33, 34] and conference papers were excluded. Articles that compared ultrasonography (USG) with MRI to evaluate MRI validity were also excluded  . The references of the selected articles were screened to complete the review process. The titles, abstracts and whole texts of the articles identified by the search were independently evaluated by two examiners (CP and ML). Any disagreements were resolved by discussion between the two examiners.