Background/Objectives: Post-polio syndrome (PPS) affects former polio patients, manifesting decades after initial infection with progressive symptoms like pain, fatigue, and muscle weakness. Diagnosis relies on the clinical criteria and exclusion of other probable causes. The purpose of this study is to determine the scope and new diagnostic value of magnetic resonance imaging (MRI) in identifying muscle involvement in PPS and distinguishing it from prior poliomyelitis (PPM). Methods: This study was approved by the Koç University Ethics Committee with Approval No. 2023.409.IRB2.090. Electronic medical archives from two academic institutions were searched for records tagged with ICD code B-91 for poliomyelitis sequalae. The resulting search query of 291 records was manually sorted for PPS and PPM, medical history, clinical examination findings, and lumbar MR images down to 32 patients. Two independent radiologists evaluated the paraspinal musculature in the MRIs using the Mercuri scale. Inter-rater agreement, comparison of the paraspinal musculatures between groups, and their relationship to leg involvement were assessed with the resulting data. Results: Inter-rater agreement was found to be almost perfect across all muscles, except for the multifidus muscle. When clinical examination findings were included for these muscles, quadratus lumborum (QL) degradation was found in both right-side (p = 0.017) and left-side (p = 0.002) leg involvement. Conclusions: QL muscle deterioration may serve as a diagnostic marker for PPS, potentially guiding lumbar pain treatment through rehabilitation.

Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant epigenetic disorder with highly variable muscle involvement and disease progression. Ongoing clinical trials, aimed at counteracting muscle degeneration and disease progression in FSHD patients, increase the need for reliable biomarkers. Muscle magnetic resonance imaging (MRI) studies showed that the appearance of STIR-positive (STIR+) lesions in FSHD muscles represents an initial stage of muscle damage, preceding irreversible adipose changes. Our study aimed to investigate fibrosis, a parameter of muscle degeneration undetectable by MRI, in relation to disease activity and progression of FSHD muscles. We histologically evaluated collagen in FSHD1 patients\' (STIR+ n = 27, STIR- n = 28) and healthy volunteers\' (n = 12) muscles by picrosirius red staining. All patients (n = 55) performed muscle MRI before biopsy, 45 patients also after 1 year and 36 patients also after 2 years. Fat content (T1 signal) and oedema/inflammation (STIR signal) were evaluated at baseline and at 1- and 2-year MRI follow-up. STIR+ muscles showed significantly higher collagen compared to both STIR- (p = 0.001) and healthy muscles (p < 0.0001). STIR- muscles showed a higher collagen content compared to healthy muscles (p = 0.0194). FSHD muscles with a worsening in fatty infiltration during 1- (P = 0.007) and 2-year (P < 0.0001) MRI follow-up showed a collagen content of 3.6- and 3.7-fold higher compared to FSHD muscles with no sign of progression. Moreover, the fibrosis was significantly higher in STIR+ muscles who showed a worsening in fatty infiltration in a timeframe of 2 years compared to both STIR- (P = 0.0006) and STIR+ muscles with no sign of progression (P = 0.02). Fibrosis is a sign of muscle degeneration undetectable at MRI never deeply investigated in FSHD patients. Our data show that 23/27 of STIR+ and 12/28 STIR- muscles have a higher amount of collagen deposition compared to healthy muscles. Fibrosis is higher in FSHD muscles with a worsening in fatty infiltration thus suggesting that its evaluation with innovative non-invasive techniques could be a candidate prognostic biomarker for FSHD, to be used to stratify patients and to evaluate the efficacy of therapeutic treatments.

UNASSIGNED: Rimmed vacuolar myopathies (RVMs) are a group of genetically heterogeneous diseases that share histopathological characteristics on muscle biopsy, including the aberrant accumulation of autophagic vacuoles. However, the presence of non-coding sequences and structural mutations, some of which remain undetectable, confound the identification of pathogenic mutations responsible for RVMs. Therefore, we assessed the clinical profiles and muscle magnetic resonance imaging (MRI) changes in 36 Chinese patients with RVMs, emphasizing the role of muscle MRI in disease identification and differential diagnosis to propose a comprehensive literature-based imaging pattern to facilitate improved diagnostic workup.
UNASSIGNED: All patients presented with rimmed vacuoles with varying degrees of muscular dystrophic changes and underwent a comprehensive evaluation using clinical, morphological, muscle MRI and molecular genetic analysis. We assessed muscle changes in the Chinese RVMs and provided an overview of the RVMs, focusing on the patterns of muscle involvement on MRI.
UNASSIGNED: A total of 36 patients, including 24 with confirmed distal myopathy and 12 with limb-girdle phenotype, had autophagic vacuoles with RVMs. Hierarchical clustering of patients according to the predominant effect of the distal or proximal lower limbs revealed that most patients with RVMs could be distinguished. GNE myopathy was the most prevalent form of RVMs observed in this study. Moreover, MRI helped identify the causative genes in some diseases (e.g., desminopathy and hereditary myopathy with early respiratory failure) and confirmed the pathogenicity of a novel mutation (e.g., adult-onset proximal rimmed vacuolar titinopathy) detected using next-generation sequencing.
UNASSIGNED: Collectively, our findings expand our knowledge of the genetic spectrum of RVMs in China and suggest that muscle imaging should be an integral part of assisting genetic testing and avoiding misdiagnosis in the diagnostic workup of RVM.

The objective of this research was to study the clinical features, genetic characteristics, muscle imaging, and muscle pathological changes of a cohort of Chinese patients with mutations in the valosin-containing protein (VCP) gene.
Nine patients from seven Chinese pedigrees were recruited. Variants were detected by next-generation sequencing and confirmed by Sanger sequencing. Thigh muscle MRIs were performed in five patients. All the patients received muscle biopsies.
Seven variants in VCP were identified, and two were novel. All the patients presented with adult-onset muscle weakness. The appearance of \"isolated island sign\" or \"contra-isolated island sign\" was observed in four of the five the patients on muscle MRIs. Muscle biopsies demonstrated the combination of neuropathic and myopathic changes in seven patients and muscle dystrophic changes in two patients. Notably, rimmed vacuoles and cytoplasmic VCP and p62-positive protein aggregates were observed in all the patients.
Our finding of novel variants expanded the mutational spectrum of the VCP gene. This cohort of Chinese patients with VCP mutations mainly present with inclusion body myopathy with predominant limb-girdle distribution. The characteristic pattern of fatty infiltration, especially the \"isolated island\" and \"contra-isolated island\" on muscle MRI, along with rimmed vacuoles in muscle biopsy, provides valuable clues for guiding genetic diagnostic workup.

Filamin C is a large dimeric actin-binding protein, most prevalent in skeletal and cardiac muscle Z-discs, where it participates in sarcomere mechanical stabilization and intracellular signaling, interacting with numerous binding partners. Dominant heterozygous mutations of Filamin C gene cause several forms of myopathy and structural or arrhythmogenic cardiomyopathy. In this report we describe clinical and molecular findings of two Italian patients, in whom we identified two novel missense variants located within the Filamin C actin binding domain. Muscle imaging, histological and ultrastructural findings are also reported. Our results underline the extreme inter- and intrafamilial variability of clinical manifestations, hence the need to extend the investigation also to asymptomatic relatives, and the relevance of a broad diagnostic approach involving muscle electron microscopy, skeletal muscle magnetic resonance imaging and next generation sequencing techniques.

LAMA2-related muscular dystrophy (LAMA2-MD) is classified into congenital muscular dystrophy type 1A (MDC1A) and autosomal recessive limb-girdle muscular dystrophy-23 (LGMDR23). The purpose of this study was to identify the involvement pattern of thigh muscles of LAMA2-MD patients on magnetic resonance imaging. Fourteen MDC1A and 3 LGMDR23 patients were included, with 21 known and 8 novel LAMA2 disease-causing variants. In LAMA2-MD, the gluteus maximus, anterior (quadriceps femoris) and posterior (adductor magnus and biceps femoris) thigh muscles were extensively and severely affected with fatty infiltration, with relatively sparing of the adductor longus. The pattern of muscle involvement was similar between MDC1A and LGMDR23, but more severe in MDC1A, as well as in LAMA2-MD patients without ambulation. The rather peculiar pattern of the adductor magnus and long head of the biceps femoris first and severely affected in the mid-thigh level was found in LGMDR23. Strong correlation between fatty infiltration and age as well as disease duration was observed for the adductor longus in MDC1A. Edema and atrophy selectively involved in some muscles. The pattern of fatty infiltration on thigh muscle MRI of LAMA2-MD could provide important information for the diagnosis, differential diagnosis and assessment of clinical severity.

Thyroid storm (TS) is a rare hyperthyroidism associated multisystem decompensation and can mimic a systemic inflammatory response syndrome. It is diagnosed in the presence of fever with cardiovascular, central nervous system, and gastrointestinal complications. Only a few reports of acute flaccid quadriplegic thyrotoxic myopathy (TM) with TS have been reported. However, muscle magnetic resonance imaging (MRI) findings in TM have not been yet been reported. Our patient underwent muscle MRI and showed some unusual features. These are discussed in this article.

BACKGROUND: the study of paraspinal muscles is pivotal for the diagnosis and staging of Amyotrophic Lateral Sclerosis (ALS), and is usually performed by electromyography.
OBJECTIVE: to evaluate the role of paraspinal muscle MRI as a diagnostic biomarker in ALS.
METHODS: we evaluated T1-w images of newly diagnosed ALS patients (n = 14), age-matched healthy controls (n = 11), patients affected by inflammatory myopathy (n = 10), and lumbar radiculopathy (n = 19), and compared them semiquantitatively by using the Mercuri Scale.
RESULTS: a significant difference in the appearance of the psoas muscle was observed between ALS patients and patients with radiculopathy (p = 0.003); after stratifying ALS patients into spinal and bulbar onsets, we found a significant difference in the appearance of the longissimus dorsi muscle between the spinal onset ALS subgroup and bulbar onset ALS subgroup (p = 0.0245), while no difference was found for multifidus (p = 0.1441), iliocostal (p = 0.0655), and psoas muscles (p = 0.0813) between the cohort subgroups.
CONCLUSIONS: paraspinal T1-w MRI could help to distinguish spinal ALS patients from healthy and pathological controls. Specifically, the study of longissimus dorsi could play the role of a diagnostic ALS biomarker.

Mutations in the BICD2 gene cause autosomal dominant lower extremity-predominant spinal muscular atrophy 2A (SMALED2A), a condition that is associated with a specific pattern of thigh and calf muscle involvement when studied by magnetic resonance imaging (MRI). Patients may present minor clinical sensory impairment, but objective sensory involvement has yet to be demonstrated.
We collected clinical data from 11 patients from five different families carrying mutations in BICD2. Genetic diagnosis was achieved using gene panel testing and skin biopsies were taken from two patients to study the epidermal nerve fiber density.
In the studied patients, three new pathogenic mutations were detected as well as the already defined pathogenic p.Ser107Leu mutation. The most frequent clinical picture was characterized by lower-limb weakness in combination with foot deformities. One patient manifested clinical and electrophysiological sensory impairment, and the epidermal nerve fiber density study of another patient revealed the existence of a small-fiber neuropathy. Muscle MRI showed a common pattern of fat deposition including selective involvement of gluteus medius and minimus at the pelvic level, the anterior compartment of the thigh and the posterior compartment of the calf, with only mild or no involvement of the intrinsic foot muscles.
We report three new pathogenic mutations in the BICD2 gene. Muscle MRI confirms the existence of a selective pattern of thigh and leg muscle involvement in SMALED2A, providing additional information regarding pelvic and foot muscles. Moreover, our results raise the possibility of sensory involvement in the disease.

Limb-girdle muscular dystrophy (LGMD) type 2A (calpainopathy) is an autosomal recessive disease caused by mutation in the CAPN3 gene. The aim of this study was to examine genetic and phenotypic features of Serbian patients with calpainopathy. The study comprised 19 patients with genetically confirmed calpainopathy diagnosed at the Neurology Clinic, Clinical Center of Serbia and the Clinic for Neurology and Psychiatry for Children and Youth in Belgrade, Serbia during a ten-year period. Eighteen patients in this cohort had c.550delA mutation, with nine of them being homozygous. In majority of the patients, disease started in childhood or early adulthood. The disease affected shoulder girdle - upper arm and pelvic girdle - thigh muscles with similar frequency, with muscles of lower extremities being more severely impaired. Facial and bulbar muscles were spared. All patients in this cohort, except two, remained ambulant. None of the patients had cardiomyopathy, while 21% showed mild conduction defects. Respiratory function was mildly impaired in 21% of patients. Standard muscle histopathology showed myopathic and dystrophic pattern. In conclusion, the majority of Serbian LGMD2A patients have the same mutation and similar phenotype.