Muscle Magnetic Resonance Imaging in Patients with Various Clinical Subtypes of LMNA-Related Muscular Dystrophy

Background： LMNA-related muscular dystrophy can manifest in a wide variety of disorders, including Emery-Dreifuss muscular dystrophy （EDMD）, limb-girdle muscular dystrophy （LGMD）, and LMNA-associated congenital muscular dystrophy （L-CMD）. Muscle magnetic resonance imaging （MRI） has become a useful tool in the diagnostic workup of patients with muscle dystrophies. This study aimed to investigate whether there is a consistent pattern of MRl changes in patients with LMNA mutations in various muscle subtypes. Methods： Twenty-two patients with LMNA-related muscular dystrophies were enrolled in this study. M RI of the thigh and/or calf muscles was performed in them. The muscle MRI features of the three subtypes were compared by the Mann-Whitney U-test. The relationship between the clinical and MRI findings was also investigated by Spearman＇s rank analyses. Results： The present study included five EDMD, nine LGMD, and eight L-CMD patients. The thigh muscle MRI revealed that the fatty infiltration of the adductor magnus, semimembranosus, long and short heads of the biceps femoris, and vasti lnuscles, with relative sparing of the rectus femoris, was the predominant change observed in the EDMD, LGMD, and advanced-stage L-CMD phenotypes, ahhough the involvement of the vasti muscles was not prominent in the early stage of L-CMD. At the level of the call; six patients （one EDMD, four LGMD, and one L-CMD） also showed a similar pattern, in which the soleus and the medial and lateral gastrocnemius muscles were most frequently observed to have fatty infiltration. The fatty infiltration severity demonstrated higher scores associated with disease progression. with a corresponding rate of 1.483 ＋ 0.075 × disease dnration （X） （r = 0.444, P - 0.026）. It was noteworthy that in six L-CMD patients with massive inflammatory cell infiltration in muscle pathology, no remarkable edema-like signals were observed in muscle MRI. Conclusions： EDMD, LGMD and advanced-staged L-CMD subtypes showed similar pattern of muscle MRI changes, while early-staged L-CMD showed somewhat different changes. Muscle MRI of L-CMD with a nluscular dystrophy pattern in MRI provided important clues for differentiating it from childhood inflammatory myopathy. The fatty infiltration score could be used as a reliable biomarker for outcome measure of disease progression.

Immune-mediated necrotizing myopathy:Report of two cases

BACKGROUND Immune-mediated necrotizing myopathy is a rare autoimmune myopathy characterized by muscle weakness and elevated serum creatine kinase,with unique skeletal muscle pathology and magnetic resonance imaging features.CASE SUMMARY In this paper,two patients are reported:One was positive for anti-signal recognition particle antibody,and the other was positive for anti-3-hydroxy-3-methylglutaryl coenzyme A reductase antibody.CONCLUSION The clinical characteristics and treatment of the two patients were analysed,and the literature was reviewed to improve the recognition,diagnosis,and treatment of this disease.

Magnetic resonance imaging： a valuable method for diagnosing chronic lumbago caused by lumbar muscle strain and monitoring healingprocess

Background Magnetic resonance imaging （MRI） is the most sensitive technique for evaluating the healing process and should be performed before the patients return to their exercise routines. The aim of this research was to diagnose chronic lumbago associated with lumbar muscle strain and to monitor healing process by MRI. Methods Sixty-five symptomatic cases of chronic lumbago caused by lumbar muscle strain were collected from March 2009 to October 2011. MRI was used to examine, diagnose and monitor the healing process. The control group included 65 random cases of asymptomatic volunteers. MRI methods included routine sequences of GRE TlWl, TSE T2WI and special sequences of T2-STIR-FS, combined with DWI. We compared the MRI characteristics of symptomatic cases before and after healing and with asymptomatic controls. Results The important MRI characteristics of chronic lumbago with lumbar muscle strain included： （1） The low back muscle showed edema. （2） The low back intermuscular spaces showed edema and/or fluid. （3） The low back spaces beside the spinous process showed edema and/or fluid. （4） The low back vertebral articular process fossae or transverse process fossae showed fluid. Of these image characteristics, the intermuscular space edema provided the best diagnostic sensitivity, Se=83%, with Y1=0.63, Tr=74%. The low back muscle edema provided the best diagnostic specificity, Sp=100%, with Y1=0.66, Tr=83%. And the spaces edema beside the spinous process provided the best diangnostic accuracy, Tr=86%, with YI = 0.71, Se=80%, Sp=91%. The diagnosis accurate could be improved by combining multiple MRI characteristics. The diagnostic accuracy could achieve n=93%, with Y1=0.86, Se=100% and Sp=86% when two characteristics were combined. After rehabilitation care, the edema disappeared on the repeated MRI. Conclusions MRI may well be a useful diagnostic method for lumbago with lumbar muscle strain. Combining routine sequences with T2-STIR-FS and DWI sequences could demonstrate the pathological changes of lumbar muscle strain and monitor the healing.

An Automated Deep Learning Based Muscular Dystrophy Detection and Classification Model

Muscular Dystrophy (MD) is a group of inherited muscular diseases that are commonly diagnosed with the help of techniques such asmuscle biopsy, clinical presentation, and Muscle Magnetic Resonance Imaging(MRI). Among these techniques, Muscle MRI recommends the diagnosis ofmuscular dystrophy through identification of the patterns that exist in musclefatty replacement. But the patterns overlap among various diseases whereasthere is a lack of knowledge prevalent with regards to disease-specific patterns.Therefore, artificial intelligence techniques can be used in the diagnosis ofmuscular dystrophies, which enables us to analyze, learn, and predict forthe future. In this scenario, the current research article presents an automated muscular dystrophy detection and classification model using SynergicDeep Learning (SDL) method with extreme Gradient Boosting (XGBoost),called SDL-XGBoost. SDL-XGBoost model has been proposed to act as anautomated deep learning (DL) model that examines the muscle MRI dataand diagnose muscular dystrophies. SDL-XGBoost model employs Kapur’sentropy based Region of Interest (RoI) for detection purposes. Besides, SDLbased feature extraction process is applied to derive a useful set of featurevectors. Finally, XGBoost model is employed as a classification approach todetermine proper class labels for muscle MRI data. The researcher conductedextensive set of simulations to showcase the superior performance of SDLXGBoost model. The obtained experimental values highlighted the supremacyof SDL-XGBoost model over other methods in terms of high accuracy being96.18% and 94.25% classification performance upon DMD and BMD respectively. Therefore, SDL-XGBoost model can help physicians in the diagnosis of muscular dystrophies by identifying the patterns of muscle fatty replacementin muscle MRI.

“Target” and “Sandwich” Signs in Thigh Muscles have High Diagnostic Values for Collagen VI-related Myopathies

Background： Collagen Vl-related myopathies are autosomal dominant and recessive hereditary myopathies, mainly including Ullrich congenital muscular dystrophy （UCMD） and Bethlem myopathy （BM）. Muscle magnetic resonance imaging （MRI） has been widely used to diagnosis muscular disorders. The purpose of this study was to evaluate the diagnostic value of thigh muscles MRI for collagen VI-related myopathies. Methods： Eleven patients with collagen VI gene mutation-related myopathies were enrolled in this study. MRI of the thigh muscles was performed in all patients with collagen VI gene mutation-related myopathies and in 361 patients with other neuromuscular disorders （disease controls）. Tl-weighted images were used to assess fatty infiltration of the muscles using a modified Mercuri＇s scale. We assessed the sensitivity and specificity of the MRI features of collagen Vl-related myopathies. The relationship between fatty infiltration of muscles and specific collagen VI gene mutations was also investigated. Results： Eleven patients with collagen VI gene mutation-related rnyopathies included six UCMD patients and five BM patients. There was no significant difference between UCMD and BM patients in the fatty infiltration of each thigh muscle except sartorius （P = 0.033）： theretbre, we combined the UCMD and BM data. Mean fatty infiltration scores were 3.1 and 3.0 in adductor magnus and gluteus maximus, while the scores were 1.3, 1.3, and 1.5 in gracilis, adductor longus, and sartorius, respectively. A “target” sign in rectus femoris （RF） was present in seven cases, and a “sandwich” sign in vastus lateralis （VL） was present in ten cases. The “target” and “sandwich” signs had sensitivities of 63.6% and 90.9% and specificities of 97.3% and 96,9% for the diagnosis of collagen Vl-related myopathies, respectively. Fatty infiltration scores were 2.0-3.0 in seven patients with mutations in the triple-helical domain, and 1.0-1.5 in three of four patients with mutations in the N- or C-domain of the collagen VI genes. Conclusions： The “target” sign in RF and “sandwich” sign in VL are common MRI features and are useful for the diagnosis of collagen VI-related myopathies. The severity of fatty infiltration of muscles may have a relationship with the mutation location of collagen VI gene.

Muscle mass loss and intermuscular lipid accumulation were associated with insulin resistance in patients receiving hemodialysis

Background An accelerated muscle wasting was the pivotal factor for protein-energy wasting in end stage renal disease. However, very few researches have examined the skeletal muscle quantity and quality in clinical patients. This study investigated the muscle morphologic changes by magnetic resonance imaging （MRI） and analyzed the related factors in hemodialysis patients. Methods Fifty-eight patients receiving maintenance hemodialysis （HD） were investigated and 28 healthy adults with gender and age matched were used as controls （Control）. Anthropometry, cytokine factors, and laboratory data were measured. The muscle and intermuscular adipose tissues （IMAT） were analyzed via a Thigh MRI. The bicep samples were observed after HE staining. Homeostatic model assessment of insulin resistance （HOMA-IR） was measured and their association with muscle wasting was analyzed. Results HD patients tended to have a lower protein diet, anthropometry data, and serum albumin, but the C reactive protein and interleukin-6 increased significantly. The MRI showed that HD patients had less muscle mass and a lower muscle/total ratio, but the fat/muscle and IMAT was higher when compared to the Control group. The muscle fiber showed atrophy and fat accumulation in the biceps samples come from the HD patients. Moreover, we found that the HD patients presented with a high level of plasma fasting insulin and increased HOMA-IR which negatively correlated with the muscle/ total ratio, but positively with the fat/muscle ratio. Conclusions Muscle wasting presented early before an obvious malnutrition condition emerged in HD patients. The main morphological change was muscle atrophy along with intermuscular lipid accumulation. Insulin resistance was associated with muscle wasting in dialysis patients.