الفهرس 
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Abstract
MRI is the diagnostic modality of choice for the characterization and full assessment of the extent and distribution of muscle diseases. MRI has the advantage of being an entirely safe non invasive diagnostic modality particularly for children and patients who need repeated study for follow up after treatment.
Although some muscles are easily evaluated clinically using physical function testing, imaging would likely be required for others to accurately determine the extent of involvement. We recommend the following pulse sequences for qualitative analysis of muscle signal: T1, T2, STIR and FLAIR. T1WIs for dystrophic changes such as fatty degeneration owing to the T1 shortening effect. T2 for edematous changes which display increased signal intensity on T2WIs caused by prolongation of T2 relaxation time. Muscle edema can be quite subtle; STIR is the fluid sensitive sequence for the early detection and grading of muscle edema.
FLAIR sequence can be used as a valuable tool for the discrimination between both signals due to its fluid attenuating capability. This role is important particularly in inflammatory muscle diseases (IIMs and autoimmune myopathy) as both pathologies are seen in the same muscle. This helps in accurate grading of edema and fatty changes
Semi Quantitative analysis is a reliable method for grading of fatty infiltration and edematous changes of hereditary and inflammatory muscle diseases respectively. Our results show significant correlation with the clinical grade and helped in the full assessment of disease progression as well as response to therapy.
Quantitative assessment can play an important role in the anticipated future treatment and follow up of muscle diseases. This role is through the identification of the most severely affected muscles which could be relied upon for the accurate quantitative assessment and disease follow up. Also, this role can be improved through continuous upgrading of the MRI software with the techniques that could separate muscles from lipid and water contents.
Proton MR spectroscopy can be used to quantify the fat content of muscle noninvasively and follow up the disease progression and response to treatment. It can be relied upon as a tool to investigate tumor metabolism in the musculoskeletal system.
MRI offers potential to study energy metabolism through 31P spectroscopy. By performing 31P spectroscopy we can study muscle energy metabolism and we can design and monitor new therapies.
It is recommended to use color MRI in future investigation which may add more achievements in the diagnosis of muscle diseases. However, colour MRI and color CT are still under trial.