الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Performing dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) of the breast has increased in the past few years due to its high sensitivity (68-100%) for detecting and evaluating abnormal breast lesions. There are various indications for breast MRI such as screening for high-risk patients with a 20% or greater lifetime risk of developing breast cancer, assessment of extent of disease and screening of the contralateral breast in patients who are newly diagnosed with primary breast cancer. Evaluation of residual disease post Breast Conserving Surgery (BCS) with positive margins, loco-regional recurrence detection, as well as response to neoadjuvant chemotherapy are also well visualized by breast MRI. In addition, assessment of inconclusive mammography findings without a sonographic correlate, suspicious nipple discharge without a sono-mammographic correlate and evaluation of metastatic axillary lymphadenopathy in case of unknown primary tumor are all indications in which breast MRI has shown high sensitivity. In some patients newly diagnosed with breast cancer, breast MRI can detect additional lesions that was not found in mammography or breast ultrasound in the ipsilateral or the contralateral breast. These additional breast lesions are classified into focus, mass, and non-mass enhancement (NME) on MRI.NME is defined as an enhancing abnormality that is not associated with the three-dimension volume, shape and outline of a mass, and they are separate from the background parenchymal enhancement (BPE). The fifth edition of the American College of Radiology (ACR) Breast Imaging-Reporting and Data System (BI-RADS) lexicon has erased some ambiguities, and modified terminologies from the fourth edition to provide more precise evaluation in descriptions of the distribution and Internal Enhancement Patterns (IEPs) of NME, with contributes to quality assurance, better communication with physicians, and enhances patient care.For morphological assessment of NME, distribution is described as focal, linear, segmental, regional, multiple regions, and diffuse. Furthermore, the IEPs are characterized as homogeneous, heterogeneous, clumped, and clustered ring. NME may be benign as pseusoangiomatous stromal hyperplasia (PASH), apocrine metaplasia, radiation effect, atypical ductal hyperplasia (ADH,) flat epithelial atypia, intraductal papilloma, radial scar or complex sclerosing lesion, or malignant like ductal carcinoma in situ (DCIS), invasive ductal carcinoma (IDC), and invasive lobular carcinoma (ILC).