الفهرس 
Acknowledgement
Aim of the WorkOnly 14 pages are availabe for public view
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Abstract
Summary
Lesion detection at contrast material–enhanced breast magnetic resonance (MR) imaging is primarily based on a lesion’s vascularity relative to normal breast tissue.
Although MR imaging has demonstrated sensitivity for the demonstration of invasive breast cancer has approached 100% in several series . this modality has demonstrated variable specificity. ,MR imaging may be still be advantageous because it can be used not only to characterize the lesion in question but also to evaluate the remainder of the breast, potentially leading to identification of unsuspected multifocal disease.
The potentially limited specificity of MR imaging has been attributed to the fact that, in addition to cancer, many benign lesions as well as presumably normal breast tissue may enhance after administration of contrast material. Enhancement of benign lesions along with presumably normal breast tissue has demonstrated overlap with enhancement of malignant lesions, both in terms of kinetic measurements and morphologic appearances, which precludes complete differentiation of benign from malignant lesions.
The primary benefit of a noninvasive test such as MR imaging undertaken prior to tissue diagnosis(ie, with core biopsy or excisional biopsy)is that it can be used to determine which lesions are likely to be benign, so that mammographic or clinical follow-up could be used in place of tissue diagnosis. When a test is used in this capacity, it must be sufficiently sensitive that the negative predictive value is very high without sacrificing specificity
Standard evaluation criteria have not been optimized for evaluating dynamic contrast enhanced breast MRI (DCE-MRI). Most evaluation criteria, especially morphologic criteria and TIC type, are subjectively interpreted. To reduce the subjectivity, quantitative analysis of the perfusion parameters may be of value in differentiation between benign and malignant breast lesions which is the aim of this study.
This study included 46 female patients ,who underwent breast MRI using the DCE- study which detect 50 lesions those lesions were analyzed using CAD software to reproduce qualitative and quantitative kinetic data and the results correlated with histopathological results.
The qualitative (curve type ) assessment shows high sensitivity 90.9% ,with specificity 52.9 % using type I curve as indicator for benign lesions and type II&III curve as indicator for malignancy with overall performance about 78%.
The quantitative assessment of 7 parameters shows that there is a significant difference between the benign and malignant lesions in ME,MRE , and wash out rate that all of them show significant higher values in malignancy than in benign lesions .TTP shows significantly lower value (earlier enhancement peak ) in malignant lesions than benign do.
The best TTP cut-off value calculated in our study using ROC curve to differentiate between benign and malignant lesions <286.5s with area under curve 0.838, and cut-off value for wash out rate about >0.22 i/s with AUC 0.857 0both parameters show higher specificity compared with the curve type assessment about 76.5 % and82.4 % for both parameters respectively with accuracy 80%. the best cut –off value for wash in rate >3.27 i/s with AUC 0.697 with higher specificity than qualitative assessment (70.6% )but lower sensitivity (69.7%) and accuracy about 70%.
The calculated sensitivity ,specificity ,NPV and PPV for previous cut –off values used for differentiation between benign and malignant lesions show highest sensitivity for TTP and wash out rate about 83.33% and80% respectively. the highest specificity was detected for wash out rate and MRE being 82.4% and 94.1%.