الفهرس 
List of AbbreviationsOnly 14 pages are availabe for public view
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Abstract
Dynamic MRI of the breast has been found to be a new modality in the diagnosis of different breast masses. The aim of this work is to study MRI pattern of different breast lesions and the value of MRI compared to ultrasound and mammography in diagnosis of breast lesions. The practical work included 28 female patients presented with palpable breast masses. Dynamic MRI examination of the breast was done to 24 patients and non contrast study was done to 4 patients only. The MRI examination was preceded by clinical evaluation of the cases as well as mammographic and sonographic examination of all cases . The results obtained by mammography, ultrasound as well as MRI examination of the breast were compared with the histopathological results and the value of MRI of the breast was assessed. The architectural pattern of breast masses as detected by MRI are very important in the correct diagnosis of breast lesions where the benign lesions are characterized by rounded or lobulated mass with regular borders. After contrast injection, they show mild homogenous enhancement with non enhancing internal septations which is present only in fibroadenoma while the malignant lesions are characterized by irregular or spiculated borders with heterogeneous or ring enhancement after contrast administration. This study confirms that MRI is helpful in the differentiation between benign and malignant breast masses based on the time / signal intensity curve where benign masses showed slow sustained increase in signal intensity while malignant masses showed rapid initial increase in signal intensity with rapid wash. So time / signal intensity curve only is insufficient for the differentiation between benign and malignant breast masses without full study of architectural pattern of breast masses. In our study , 90% of benign breast tumors showed relative percentage increase signal intensity less than 60% and about 72.2% of malignant breast tumors showed relative percentage increase signal intensity more than 60% within the first minute. The sensitivity , specificity and accuracy of MRI compared to ultrasound and mammography revealed that MRI has more accuracy and sensitivity but lower specificity. This is due to that some benign breast lesions and normal breast tissue during different times of the menstrual cycle may show enhancement similar to malignant lesions. This study showed significant improvement in diagnostic accuracy when the interpretation based on combined quantitative and qualitative parameters. Dynamic MRI of the breast has many advantages including absence of radiation hazards, safety of its contrast media, in addition to locoregional staging of malignant masses and detection of multifocal breast lesions. Disadvantages of MRI examination of breast include its high cost, its long examination time and its low specificity. Based on our results , MR imaging of the breast is recommended in the following situations : -Differentiation between benign and malignant breast masses where the role of breast MRI is complementary rather than competitive to ultrasound and mammography in diagnosis of breast masses . - Detection of recurrence in the residual breast parenchyma after breast conserving surgery . - Detection of suspected chest wall involvement in cases of malignant breast lesions near the chest wall - Detection of malignant breast masses in patients with free mammographic and sonographic examination in whom the axilla is involved by suspected malignant lymph nodes . - For exclusion of multicentricity and exact determination of the tumor size, if conservative surgery is documented. In conclusion, dynamic MRI has proved to be a precious technique in differentiation between benign and malignant breast masses based on both quantitative and qualitative assessment . We advice the use of dynamic MRI whenever there is problematic cases by mammography and / or ultrasonography .