Towards defining muscular regions of interest from axial magnetic resonance imaging with anatomical cross-reference: a scoping review of lateral hip musculature

Abstract

Background Measures of hip muscle morphology and composition (e.g., muscle size and fatty infiltration) are possible with magnetic resonance imaging (MRI). Standardised protocols or guidelines do not exist for evaluation of hip muscle characteristics, hindering reliable and valid inter-study analysis. This scoping review aimed to collate and synthesise MRI methods for measuring lateral hip muscle size and fatty infiltration to inform the future development of standardised protocols. Methods Five electronic databases (Medline, CINAHL, Embase, SportsDISCUS and AMED) were searched. Healthy or musculoskeletal pain populations that used MRI to assess lateral hip muscle size and fatty infiltration were included. Lateral hip muscles of interest included tensor fascia late (TFL), gluteus maximus, gluteus medius, and gluteus minimus. Data on MRI parameters, axial slice location, muscle size and fatty infiltrate measures were collected and analysed. Cross referencing for anatomical locations were made between MRI axial slice and E-12 anatomical plastinate sections. Results From 2684 identified publications, 78 studies contributed data on volume (n = 31), cross sectional area (CSA) (n = 24), and fatty infiltration (n = 40). Heterogeneity was observed for MRI parameters and anatomical boundaries scrutinizing hip muscle size and fatty infiltration. Seven single level axial slices were identified that provided consistent CSA measurement, including three for both gluteus maximus and TFL, and four for both gluteus medius and minimus. For assessment of fatty infiltration, six axial slice locations were identified including two for TFL, and four for each of the gluteal muscles. Conclusions Several consistent anatomical levels were identified for single axial MR slice to facilitate muscle size and fatty infiltration muscle measures at the hip, providing the basis for reliable and accurate data synthesis and improvements in the validity of future between studies analyses. This work establishes the platform for standardised methods for the MRI assessment of lateral hip musculature and will aid in the examination of musculoskeletal conditions around the hip joint. Further studies into whole muscle measures are required to further optimise methodological parameters for hip muscle assessment.

Sex-Specific Differences in Hip Muscle Cross-sectional Area and Fatty Infiltration in Patients With Femoroacetabular Impingement Syndrome

“…Indeed, muscle CSA is just an estimate of the total muscle size. Mean CSA measures on consecutive MRI slices over the whole muscle length or volumetric muscle analysis is recommended for future studies, 28 also to adjust for possible skewness of the axial MRI slices. The multicenter origin of the MRI scans did not allow this procedure to be conducted in the current study.…”

The Cross-Sectional Area Assessment of Pelvic Muscles Using the MRI Manual Segmentation among Patients with Low Back Pain and Healthy Subjects

“…Additionally, manual segmentation appeared to be the most appropriate method in cases of abundant infiltration of adipose tissue especially relevant in gluteal muscles. Therefore, manual segmentation method appeared to be the most precise method for determining their volume, serving as the gold standard for segmentation [ 10 , 15 , 24 ]. Additionally, manual segmentation is a conventional method for obtaining CSA [ 10 , 11 , 12 , 13 , 14 ].…”

“…Magnetic resonance imaging (MRI) is a standard method in the diagnosis of patients with symptoms of LBP but constitutes rather unproductive in patients with chronic low back pain with the exception of muscle segmentation of acquired resonance images [ 10 , 11 , 12 , 13 , 14 ]. Patients with chronic LBP present morphological changes, such as alterations in muscle activity and strength associated with variations in volume and cross-sectional area (CSA) of the lumbopelvic region.…”

“…Manual segmentation, which is considered the “gold standard” in medical image segmentation, allows the most precise analysis of magnetic resonance images. Moreover, cross-sectional area parameter can be obtained faster than volumetric measurement, which is especially important in time consuming manual segmentation [ 3 , 10 , 12 , 14 , 23 ].…”

Intra-operator Repeatability of Manual Segmentations of the Hip Muscles on Clinical Magnetic Resonance Images

“…Despite new imaging sequences, such as Dixon scans, have been developed to highlight specific features (e.g. fat infiltration) in soft-tissues and muscles, T1-weighted MRI images are typically preferred to assess muscle size and morphology, and fat infiltration [ 14 , 25 ]. Indeed, T1-weighted images are characterized by excellent anatomical detail and high signal-to-noise ratio (compared to other MRI sequences), which makes them ideal to assess muscles [ 26 , 27 ].…”