الفهرس 
Physics Of Magnetic Resonance Spectroscopy (MRS)Only 14 pages are availabe for public view
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Abstract
From our study we observed that; • Conventional MRI is useful in diagnosing some types of soft tissue tumors and tumor like masses with no need for further assessment, such as lipoma, hemangioma and abscess. • In most cases, we can depend on conventional MRI in differentiating benign from malignant tumors by the size of the tumors, extension, invasion to the surrounding structures, SI and pattern of enhancement, in addition to clinical data we can reach diagnosis in most cases. • MRS is a simple non invasive technique which can help in tumor differentiation, characterization, grading and in follow up after treatment as it takes short time (maximum 7 minutes) and could be corporate with the routine MRI examination in the same setting. • CSI should be performed for large lesions as it provide data from all area and can be used for comparison between the tumor and the surrounding. • SVS should be carried in certain situations including; small lesions (less than 2cm), very superficial lesions and in lesions at inhomogeneous field like the neck. • For controversial lesions, 1H MRS may helpful at least for differentiating benign from malignant tumors by the detection of high cho peak and estimation of cho/cr. • High cho peak is helpful in most cases, taking in mind that the presence of large areas of cystic degeneration, malignant tumors of low cellularity will give false negative peak. On the other hand, rapidly proliferating cells as in inflammatory process may give false positive cho peak. • Cho/cr ratio is more reliable than intensity of cho signal only as it differs from tumor to other of same pathology and according to the matrix size used but cr is more constant and can be used as a reference peak. • Other metabolites can help in differentiating certain tumors such as NAA in tumors of neurogenic origin. • Unassigned signals can also be used such as strong signals at 0.9, 1.3 ppm in adipocytic tumors. • 1H MRS can help in follow up of malignant soft tissue tumors after treatment by differentiating recurrence from post operative or post radiation changes. • MRS is still in need of further study upon its application in musculoskeletal system as regard the optimum technique for best results as well as spectral analysis. Finally, from the present work we concluded that the combination of different imaging modalities side by side with clinical data of the patient is helpful to approach accurate diagnosis. MRI is enough in many cases and the need of 1H MRS should be limited to the controversial cases only which could not be identified. That means; the suspected lesions which need further assessment either to define whether it is benign or malignant or if in need to narrow the differential diagnosis, MRS will be helpful