الفهرس 
Introduction
AIM OF WORKOnly 14 pages are availabe for public view
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Abstract
Despite the excellent soft tissue contrast provided by MRI, the sensitivity and specificity with which this modality defines tumor type and grade is limited, Overcoming these problems requires the development of new imaging modalities that highlight functional or metabolic properties of the tumor.
Advanced magnetic resonance imaging (MRI) techniques, such as MR spectroscopy, diffusion and perfusion MR imaging techniques can give important in vivo physiologic and metabolic information, complementing morphologic findings from conventional MRI in the clinical setting.
Magnetic Resonance Spectroscopy (MRS) provides, beside the definition of extent of changes, the metabolic fingerprint of a lesion which can be further enhanced by the analysis of the quantitative ratio of tissue metabolites such as N-acetylaspartate (NAA), creatine, choline and lactate.
Perfusion-weighted imaging (PWI) is a new tool which provides information about the hemodynamics of anatomic tissue or lesions and is mainly used in the assessment of disturbed cerebral hemodynamics. Diffusion-weighted imaging (DWI) provide information about physiological properties of the tumor that have been linked to, cellularity, structural integrity, MR diffusion imaging has become a powerful, multifaceted tool both for very basic clinical needs and for advanced, specialized diagnosis and treatment planning.With the appearance of MR spectroscopy, contrast enhanced perfusion and diffusion imaging, a step towards obtaining radiological base line data, nearly equivalent to the histopathological results. This study aimed to assess the role of MR perfusion in evaluation and differentiation of intra axial malignant brain tumours.
The study included 53 patients with different lesions at conventional MRI. All the patients underwent conventional MR study and advanced neuro image package including MR spectroscopy, perfusion and diffusion examination. all lesions were histopathologically proven and matching with the diagnosis. The use of Advanced neuro-imaging had an important role in the grading of brain gliomas a threshold value of 1.8 for Cho/NAA ratio gave a sensitivity of 100% and a specificity of 76.2%, 1.7 for rCBV ratio gave a sensitivity of 96.8% and a specificity of 95.2% and 0.8 X 10-3mm2/sec for ADC value gave a sensitivity is 81.2% and specificity is 95.2%.Differentiation between metastasis and high grade gliomas, by using multi-voxel sequence with intermediate TE for elevation of Cho level in the peri-lesional edema, if elevated in the lesion and peri-lesional area, a high grade glioma is suggested. a threshold value of 6 for Cho/NAA ratio for the mass gave a sensitivity of 80% and a specificity of 100%, for the edema 0.8 gave a sensitivity of 92% and a specificity of 100%.
Also the same idea for perfusion in the peri-lesional edema , if low perfusion , a metastasis is suggested. 5.3 for rCBVt ratio gave a sensitivity of 90% and a specificity of 100% , 0.6 for rCBVp gave a sensitivity of 94% and a specificity of 100%. Finally advanced neuro-imaging including MR spectroscopy, perfusion and diffusion imaging in this study were of great benefit in the diagnosis of single malignant brain tumor.