الفهرس 
-Anatomy of the breastOnly 14 pages are availabe for public view
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Abstract
Breast cancer is the most common cancer, and is the second leading cause of cancer-related mortality in women. Thus, prevention and screening have become important health issues. Early detection and treatment at proper time lead to good prognosis.
Diagnosis of breast cancer is made primarily on the basis of mammographic and ultrasonographic (US) results, with good specificity but low sensitivity, also have some limitations such as inaccurate differentiation between benign and malignant lesions and estimation of the size of malignant tumors.
The MR imaging has a very high sensitivity for detection of breast cancer with most studies reporting sensitivity of 90% or greater.
Dynamic contrast-enhanced MRI (DCE-MRI) of the breast has a high sensitivity for breast cancer detection and has recently been shown to be the most sensitive breast screening technique for women at high risk, and is also more accurate than mammography or ultrasound for the delineation of the extent of disease in patients with a recent diagnosis of cancer
Contrast material–enhanced MR imaging of the breast is known for high sensitivities of 71%–100%. However, variable specificity (75%–98%) may lead to unnecessary biopsies, However, dynamic-enhanced breast MRI has some disadvantages such as being time-consuming and costly and the possible side effects of the contrast media.
The breast imaging lexicon — Breast Imaging Reporting and Data System (BI-RADS) enables a standardized and consistent description of the morphologic and kinetic characteristics of breast lesions. However, many challenges are still present when interpreting breast enhancement patterns and kinetics. To decrease the number of unnecessary biopsies, a more precise way to differentiate between false-positive enhancing lesions and true-positive malignancies is needed.
Diffusion-weighted (DW) MR imaging has been investigated as a means of overcoming the limitations of conventional MR imaging assessment, which is reliant on inherent unique tissue contrast mechanism. DW imaging makes use of the variability of brownian motion of water molecules in tissue. DWI is a powerful imaging tool that provides unique information related to tumor cellularity and the integrity of the cellular membrane.
With respect to breast DWI a potential role for the apparent diffusion coefficient (ADC), a quantitative measure that is directly proportional to the diffusion of water and inversely proportional to the tumor cellular density, has been reported to be useful for characterizing breast tumors and distinguishing malignant tissues from benign tissues.
So use of DWI as a diagnostic tool can increase the specificity of breast MR imaging and can reduce the number of false-positive results and associated unnecessary biopsies.
The technique can be applied widely for tumor detection and tumor characterization and for the monitoring of response to treatment. In addition, DWI appears to have the ability to predict treatment response to chemotherapy and radiation treatment. The chemotherapy causes cell lysis that leads to increase in the extracellular water and so increase in the apparent diffusion coefficient (ADC).
Evaluation of peri- tumor tissues and assessment of axillary lymph nodes as well as differentiation of cancer recurrence from surgical scar are also application of diffusion imaging in the breast. Although DWI is not currently recommended as a stand-alone diagnostic tool, future studies without injection of contrast agents may support the use of DWI in this capacity.