الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Magnetic resonance imaging (MRI) has gained an important role in the diagnosis, staging and followup of musculoskeletal diseases due to its precise visualization of degenerative changes, tumors and inflammatory diseases, yet it is not capable of providing relevant clues to the diagnosis of malignancy. New techniques of functional MRI can now extract physiological information while presenting the high anatomic specificity, opening up new possibilities in diagnostic imaging. Examples of such functional imaging modalities include; diffusionweighted MR imaging (DWI) of microscopic water motion and direct imaging of metabolites using magnetic resonance spectroscopy (MRS). Recently DWI and spectroscopy has a further aid in accurate diagnosis of malignant tumor, and provide reliable and adequate information for differentiation benign from malignant tumors. The purpose of this study was to provide an understanding of the basic techniques and applications of new functional MRI modalities in assessment of musculoskeletal neoplasms specially to differentiate between benign & malignant. In this study, 41 patients with bone and soft tissue tumors were enrolled, all patients underwent thorough history taking, full clinical examination, Xray, CT, as well as conventional and functional MR examination. <U+DBC0><U+DCC2> Results of this study show; <U+DBC0><U+DC88> In differentiation between malignant and benign lesions; quantitative ADC map was more accurate than qualitative DWIs. ADC map could significantly differentiate between benign and malignant musculoskeletal tumors. Furthermore, ADC values were highly statistically significance in group of bone tumors. On contrary, ADC map is of no value in soft tissue tumors. There was no statistical significance difference in differentiation between benign and malignant soft tissue tumors. ADC map could provide valuable information in differentiation between benign and malignant tumors of no especial component (e.g; osteiod osteoma, GCT, ABC, osteosarcoma, Ewing, lymphoma, myeloma and metastasis). ADC map could not differentiate between tumors containing special components (myxomatous, cartilaginous and fibrous components): As, no significant difference could be detected between benign and malignant cartilaginous tumors, also myxomatous tumors had high ADC values similar to cystic components. ADC is not valid for detection of any bone changes (calcification, ossification, osteoprotic and osteolytic changes). DWI could correctly differentiate solid from cystic lesion. <U+DBC0><U+DC88> In differentiation between malignant and benign lesions; qualitative detection of choline peak was more accurate than quantitative approach using the integral ratios. Identification of choline peak in proton MR spectroscopy of a mass highly favors its malignancy (specificity 82%), however it can not be used to confirm benign nature of a mass due to its low sensitivity (66%). CSI provides valuable information by its ability to assess whole tumor areas and surrounded tissues. Obtaining adequate spectra is not guaranteed in all cases, several factors are affecting the obtained signal due to technical or individual inhomogeneity, which is relevant outside the brain. No special significance value was found on observing NAA peak on some tumor spectra. from this study it can be concluded that: <U+DBC0><U+DC80> The combination of proton DWI and/or MRS with the conventional MRI improve the diagnosis of musculoskeletal tumors. However, the use of functional MRI should be complementary to conventional MRI and not used alone. Diffusionweighted imaging is an ideal additional imaging technique. It is a rapid imaging technique, requires very short time (about 120 seconds). It is cheap noninvasive imaging modality (with the same requirements of conventional MR imaging and needs no contrast). Data derived from diffusion study would change the way of radiological evaluation of a mass, tumor characterization, treatment planning and monitoring of response to therapy. Magnetic resonance spectroscopy offers a non invasive technique for evaluating biochemical and metabolic changes in tissues, yet the homogeneity needed to obtain adequate spectral curve without artifact is not always available in all assessed regions. Also the relatively long time needed to perform it (710 min.) makes its introduction into the routine work still not practical.