الفهرس 
Normal Anatomy and MRI Anatomy of the BreastOnly 14 pages are availabe for public view
 |  | from | 177 |  |  |
| | | from | 177 | | |
Abstract
Breast cancer is the most common female malignancy, counting for 32 % of all female cancers. The incidence is increasing and a woman now has a 1 in 8 chance of developing breast cancer in her lifetime.
The exact cause or causes of breast cancer remain unknown. Yet scientists have identified a number of risk factors that increase a person’s chance of getting this disease, some of these risk factors are family history of breast cancer, moderate alcoholic consumption, obesity, exposure to the ionizing radiation and hormone therapy.
While all women over the age of 40 should undergo routine screening for breast cancer, women who are at a high risk for developing cancer may want to begin this process at an earlier age and with greater frequency. Increasing surveillance can increase the possibility that cancer could be found at an early stage when treatment is most likely to produce a cure.
Although, conventional imaging modalities as mammography and ultrasound remain the method of choice for routine screening programs and is the 1st imaging aid, but Conventional assessment have well-known limitations, such as inaccurate differentiation between benign and malignant lesions and estimation of the size of malignant tumors.
The sensitivity of breast MRI for the detection of cancer is the greatest of all imaging techniques, ranging from 90–100% and when the findings of conventional imaging are inconclusive (i.e. BI-RADS 0), MRI can be used as a problem-solving modality, it is also better at identifying the true extent of cancer when multifocal disease or ductal carcinoma in situ is present.
Although contrast material–enhanced magnetic resonance (MR) imaging of the breast is exquisitely sensitive for detection of invasive breast cancer, its reported specificity is variable. Two principal strategies have evolved to improve specificity: rapid dynamic imaging of gadolinium enhancement and high-spatial-resolution imaging. Although the former technique provides valuable diagnostic information, whole breast rapid dynamic MR imaging produces large, unwieldy data sets that are difficult to correlate with separately acquired high-spatial-resolution images.
High spatial resolution is important because some of the most powerful diagnostic criteria that are in use for differential diagnosis are based on lesion morphology specifically, margins and internal architecture.
Most researchers agree that high spatial resolution and rapid imaging are mandatory. Evaluation of the morphology of the lesion has to be done on the early postcontrast image, for the optimal discrimination between lesion enhancement and enhancement of the surrounding tissue.
The morphological signs of the qualitative analysis of the MR images for malignant tumors include the early enhancement of the lesion, irregularity of the borders , peripheral enhancement of the lesion, the inhomogencity of enhancement, the converging vessels toward the tumor and the signs of spread of malignancy . While the quantitative analysis include the high amplitude of enhancement curve and the early wash out of the contrast from the enhanced lesion. In addition, Patterns of time intensity curves may enable us to predict the histologic type.
Although breast MRI is highly sensitive, its disadvantages include cost, variations in technique and interpretation, imperfect specificity, variation in parenchymal enhancement during the menstrual cycle (the midcycle is optimal).
We can conclude that MRI detection, localization, characterization and staging of breast tumors offer a cost effective method for improving the effectiveness of treatment and lowering the cost and morbidity associated with unnecessary therapies.