الفهرس 
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Abstract
LGMD is an umbrella term given to a group of rare, highly heterogeneous, autosomal neuromuscular disorders (Murphy & Straub, 2015). Over the last few years, new studies have been published on LGMD. As of today more than 30 different genetic subtypes of LGMD have been identified (Straub et al., 2018).
Diagnosis of LGMD subtypes is considered challenging due to a variety of clinical phenotypes, low specificity of diagnostic tools and complex approaches of molecular genetics (Straub & Bushby., 2006).
In recent years, MRI has been increasingly used in clinical practice to aid in the diagnosis of inherited myopathies (Pichiecchio et al., 2017). The identification of patterns of muscle involvement and sparing in different types of muscular dystrophy suggests that muscle MRI could be used in a diagnostic capacity (Leung, 2017).
Neuromuscular imaging in LGMD is used for identification of pattern and degree of muscle involvement, which can limit differential diagnosis and aid clinical diagnosis, as well as monitoring treatment and disease progression (Leung et al., 2017).
This study is an exploratory diagnostic accuracy study conducted on 103 LGMD patients; to evaluate the role of muscle MRI of to be used as a tool for diagnosis and differentiation of patients with LGMD and as a guidance for the needed immunological and genetic studies to confirm their diagnosis.
The mean age of the patients was (25.69 ± 10.22), (50.5%) of patients were males, while (74.8%) of patients had consanguineous parents.
The final diagnosis of all the patients of LGMD group (N=103) was, confirmed Dysferlinopathy patients (25.2%), probable Dysferlinopathy (3.9%), confirmed GNE (5.8%), probable GNE (1%), confirmed Sarcoglycanopathy (22.3%), probable Sarcoglycanopathy (9.7%), confirmed Calpainopathy (11.7%), probable Calpainopathy (7.8%), confirmed rare subtypes (9.7%) and probable rare subtypes cases (2.9%). The total number of cases with confirmed final diagnosis was 77 patients, (33.8%) were Dysferlinopathy, (29.9%) were Sarcoglycanopathy, (15.6%) were Calpainopathy, (13%) belonged to the rare subtypes and (7.8%) were GNE. Which means that the most frequent subtypes in our cohort are Dysferlinopathy then Sarcoglycanopathies.
The most affected muscles by fatty infiltration in confirmed Sarcoglycanopathy group in the pelvis were Gluteus Maximus, Medius and Minimus. In the thigh were Adductors, Biceps Femoris, Semimembranosus, Semitendinosus. In the leg were Medial and Lateral head of Gastrocnemius, Soleus. In the trunk were Erector Spinea, Serratus Anterior. In the upper limbs were Subscapularis, Biceps Brachii. This distribution was similar between the confirmed and probable cases and agreed with Wang et al. (2018) and Tasca et al. (2018).
The most affected muscles by fatty infiltration in confirmed Dysferlinopathy group in the thigh were Semimembranosus, Adductors, Semitendinosus. In the leg were Medial head of Gastrocnemius and Lateral heads of Gastrocnemius and Soleus. In the pelvis were Gluteus Maximus and Minimus. In the trunk were Erector Spinea, Anterior abdominal wall muscles. In the upper limbs were Biceps Brachii and Triceps. This distribution was slightly different between the confirmed and probable cases and agreed with Arrigoni et al. (2018) and Diaz-Manera et al. (2018).
The most affected muscles by fatty infiltration in confirmed Calpainopathy group in the thigh were Adductors, Biceps Femoris, Semimembranosus, Semitendinosus. In the leg were Medial and Lateral heads of Gastrocnemius and Soleus. In the pelvis were Gluteus Maximus, Medius and Minimus. In the trunk were Erector Spinea then Serratus Anterior and Iliopsoas muscles. In the upper limbs were Brachioradialis, Biceps Brachii and Subscapularis. This distribution was similar between confirmed and probable cases and agreed with Stramare et al., (2010), Arrigoni et al., (2018) and Aivazoglou et al., (2022).
The most affected muscles by fatty infiltration in confirmed GNE group in the thigh were the Adductor Magnus, Semimembranosus and Semitendinosus, Biceps Femoris. In the leg were Tibialis Anterior, Tibialis Posterior and Medial head of Gastrocnemius. In the pelvis were Gluteus Maximus then Minimus. In the trunk was Erector Spinea. In the upper limbs were Subscapularis, Brachioradialis and Wrist Flexors. This distribution agreed with Liu et al. (2021).
The muscle edema in MRI was positive in 13 patients (12.6%) of the LGMD group.
Comparative study between the 6 groups revealed highly significant difference as regards total Mercuri scale, total MRC score, total inverted MRC score, percentage of muscle edema in MRI (p > 0.05).
We have found a good correlation between the clinical evaluation (inverted MRC score) and the imaging evaluation (Mercuri scale) in the Dysferlinopathy and GNE groups, and a strong correlation in the Sarcoglycanopathy and Calpainopathy groups and in total LGMD patients, yet there was no correlation in the rare subtypes group.
Spearman’s correlation analysis shows that; total muscle power scale had a highly significant negative correlation with total MRI fatty infiltration grade (p < 0.01).