Fatty Infiltration Of Supraspinatus Muscle Research Articles

High-accuracy detection of supraspinatus fatty infiltration in shoulder MRI using convolutional neural network algorithms.

The supraspinatus muscle fatty infiltration (SMFI) is a crucial MRI shoulder finding to determine the patient's prognosis. Clinicians have used the Goutallier classification to diagnose it. Deep learning algorithms have been demonstrated to have higher accuracy than traditional methods. To train convolutional neural network models to categorize the SMFI as a binary diagnosis based on Goutallier's classification using shoulder MRIs. A retrospective study was performed. MRI and medical records from patients with SMFI diagnosis from January 1st, 2019, to September 20th, 2020, were selected. 900 T2-weighted, Y-view shoulder MRIs were evaluated. The supraspinatus fossa was automatically cropped using segmentation masks. A balancing technique was implemented. Five binary classification classes were developed into two as follows, A: 0, 1 v/s 3, 4; B: 0, 1 v/s 2, 3, 4; C: 0, 1 v/s 2; D: 0, 1, 2, v/s 3, 4; E: 2 v/s 3, 4. The VGG-19, ResNet-50, and Inception-v3 architectures were trained as backbone classifiers. An average of three 10-fold cross-validation processes were developed to evaluate model performance. AU-ROC, sensitivity, and specificity with 95% confidence intervals were used. Overall, 606 shoulders MRIs were analyzed. The Goutallier distribution was presented as follows: 0 = 403; 1 = 114; 2 = 51; 3 = 24; 4 = 14. Case A, VGG-19 model demonstrated an AU-ROC of 0.991 ± 0.003 (accuracy, 0.973 ± 0.006; sensitivity, 0.947 ± 0.039; specificity, 0.975 ± 0.006). B, VGG-19, 0.961 ± 0.013 (0.925 ± 0.010; 0.847 ± 0.041; 0.939 ± 0.011). C, VGG-19, 0.935 ± 0.022 (0.900 ± 0.015; 0.750 ± 0.078; 0.914 ± 0.014). D, VGG-19, 0.977 ± 0.007 (0.942 ± 0.012; 0.925 ± 0.056; 0.942 ± 0.013). E, VGG-19, 0.861 ± 0.050 (0.779 ± 0.054; 0.706 ± 0.088; 0.831 ± 0.061). Convolutional neural network models demonstrated high accuracy in MRIs SMFI diagnosis.

Beige fibro-adipogenic progenitor transplantation reduces muscle degeneration and improves function in a mouse model of delayed repair of rotator cuff tears

Muscle atrophy and fatty infiltration (FI) are common occurrences following rotator cuff (RC) tears. Tears of all sizes are subject to muscle degeneration. The degree of muscle degeneration following RC tears is highly correlated with repair success and functional outcomes. We have recently discovered that muscle fibro-adipogenic progenitors (FAPs) can differentiate into uncoupling protein 1 (UCP-1)-expressing beige adipocytes and induce muscle regeneration. This study evaluated the potential of local cell transplantation of beige adipose FAPs (BAT-FAPs) to treat RC muscle degeneration in a murine model of RC repair. BAT-FAPs were isolated from muscle in UCP-1 reporter mice by flow cytometry as UCP-1+/Sca1+/PDGFR+/CD31-/CD45-/integrin α7-. C57/BL6J mice underwent supraspinatus tendon tear with suprascapular nerve transection followed by repair 2or 6 weeks after the initial injury. At the time of repair, mice received either no additional treatment, phosphate-buffered saline injection, or BAT-FAP injection. Functional outcomes were assessed by gait analysis. Mice were humanely killed at 6 weeks after cell transplantation. Supraspinatus muscle FI, fibrosis, muscle fiber size, and vascularity were analyzed and quantified via ImageJ. Analysis of variance with post hoc Tukey test and P <.05 was used to determine statistical significance. Cell transplantation diminished fibrosis, FI, and atrophy and enhanced vascularization in both delayed repair models. Cell transplantation resulted in improved shoulder function as assessed with gait analysis in both the delayed repair models. BAT-FAPs significantly reduced muscle degeneration and improved shoulder function after RC repair. BAT-FAPs hold significant promise as a therapeutic adjunct to repair for patients with advanced RC pathology.

Rotator Cuff Tear Morphologic Parameters at Magnetic Resonance Imaging: Relationship With Muscle Atrophy and Fatty Infiltration and Patient-Reported Function and Health-Related Quality of Life.

The aim of this study was to determine the relationship between rotator cuff tear (RCT) morphologic parameters and muscle atrophy and fatty infiltration, and patient-reported outcome measures, in patients with symptomatic full-thickness RCT. Rotator cuff tear location, length, width, thickness, and musculotendinous junction position were assessed in 57 magnetic resonance imaging scans and correlated to the outcome measures using multivariate regression analysis. Supraspinatus tendon tear length (odds ratio [OR], 2.218; 95% confidence interval [CI], 1.460-3.370), supraspinatus musculotendinous junction position (OR, 2.037; 95% CI, 1.322-3.137), and infraspinatus tendon tear width (OR, 2.371; 95% CI, 1.218-4.615) were identified as the strongest determinants of supraspinatus muscle atrophy, supraspinatus muscle fatty infiltration, and infraspinatus muscle fatty infiltration, respectively. The extent of supraspinatus tendon and musculotendinous junction retraction influences the development of supraspinatus muscle atrophy and fatty infiltration, whereas the extent of infraspinatus tendon tear width influences the development of infraspinatus muscle fatty infiltration. Morphologic parameters defining RCT at magnetic resonance imaging did not correlate with clinical shoulder function scores.

ARTHROSCOPIC REPAIR OF LARGE AND MASSIVE ROTATOR CUFF TEARS: CLINICAL OUTCOMES AND POSTOPERATIVE MRI FINDINGS

Purpose of the study – to identify incidence rate of recurrent rotator cuff (RC) tears, to evaluate outcomes of arthroscopic bone-tendon anchor suture, to determine the factors influencing arthroscopic treatment outcomes.Materials and methods. Medical history data, pre-operative x-rays and MRI of shoulder joints of 305 patients (main group) who underwent arthroscopic bone-tendon anchor suture repair of large or massive RC tears during 2010-2016 were included in the study. Follow up period ranged from 1 to 6 years postoperatively with mean value of 25,6±4,5 months. Telephone survey of patients was conducted after the surgery as well as a single examination of patients with evaluation by functional scales – UCLA, ASES, CS, VAS, DN4. Preoperative standard x-rays in AP and axial views were done in all patients. Arthropathy severity was evaluated by K.Hamada classification. Comparison of patient specific data, features of RC lesions and surgical treatment was made by Kruskal-Wallis test.Results. Good outcomes by ASES, CS and UCLA functional scales were obtained in 15 (5%) of patients, satisfactory – in 213 (69.8%), poor – in 77 (25.2%). Postoperative MRI data provided the following sub-distribution of patients: 49 (41.1%) patients with complete repair of RC tendons lesions, 38 (31.9%) patients with partial repair and 33 (27.0%) patients with recurrent tear of reconstructed tendon. Correlation analysis allowed to establish the limits for achieving good outcomes of arthroscopic bone-tendon anchor suturing for significant association with infraspinatus muscle atrophy (not exceeding 40%) and fatty infiltration of supraspinatus muscle (not exceeding 23.5%).

Effect of age on fatty infiltration of supraspinatus muscle after experimental tendon release in rats

BackgroundRotator cuff tendon tear is a leading cause for atrophy, fibrosis and fatty infiltration of the rotator cuff muscles. The pathophysiology of fatty muscle infiltration is not well understood. An animal model suited to study cellular and molecular mechanisms would therefore be desirable. While a rat model has been established for chronic rotator cuff tendon pathology, sufficient and easily identifiable fatty infiltration of the muscle has not yet been shown in rats. As younger animals regenerate better, we hypothesized that the absence of a sufficient amount of fatty infiltration in previous experiments was due to the selection of young animals and that older animals would exhibit higher amounts of fatty infiltration after tendon tear.FindingsThe supraspinatus tendon was released using tenotomy in 3 young (6 weeks old) and in 3 aged (24 months old) Sprague Dawley rats (group I and II). Another 3 aged (24 months old) rats underwent sham surgery and served as a control group (group III). In group I and II retraction of the musculotendinous unit was allowed for 6 weeks. All animals were sacrificed 6 weeks after surgery and the supraspinatus muscles were harvested. Each sample was examined for fatty infiltration of the muscle by histological methods and micro-CT. In histology, fat cells were counted with a 10-fold magnification in 6 fields of view twice. An adjusted measurement setup was developed for the use of micro-CT to quantify the absorption coefficient of the muscle as a reciprocal indicator for fatty infiltration, based on the established procedure for quantification of fatty infiltration on CT in humans.Tenotomy resulted in an insignificant increase of fat cells in histological sections in both, aged and young rats. Micro-CT was able to quantify small differences in the absorption coefficients of muscle samples; the absorption coefficient was 8.1% ± 11.3% lower in retracted muscles (group I and II) compared with the control (group III), indicating a tendency towards a higher amount of intra- and/or extracellular fat. Absorption was 4.28% ± 3.2% higher in aged compared with young muscles; however, this difference could not be confirmed by histology.ConclusionsSubstantial fatty muscle infiltration following chronic retraction after supraspinatus tenotomy could be documented histologically neither in young nor aged rats. Although micro-CT was able to reveal minor differences in absorption between the studied groups, the differences were too small to make the rat supraspinatus model interesting to study fatty infiltration of the chronically retracted muscle.