الفهرس 
Anatomy of the BreastOnly 14 pages are availabe for public view
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Abstract
Summary
Magnetic resonance (MR) imaging is commonly
performed in the preoperative setting for breast cancer to
identify the extent of disease, and to assess for both ipsilateral
foci of multifocal or multicentric involvement and contralateral
disease. This can significantly alter the course of treatment,
from breast-conserving surgery to more extensive surgery or
mastectomy.
Prior to the dynamic contrast-enhanced series,precontrast
imaging are performed to improve the specificity of lesion
characterization by means of evaluation of blood-, fat-, and
fluid-containing lesions, and depiction of susceptibility
artifact–causing structures such as postbiopsy markers or clips
DCIS can be hypo- to isointense on precontrast T1-
weighted and fat-saturated T2-weighted images.
The most commonly reported MR imaging manifestation
of DCIS is clumped nonmasslike enhancement in a ductal,
linear, segmental, or regional distribution.
The most frequent enhancement pattern is clumped
enhancement, followed by heterogeneous, homogeneous,
reticular, and punctate.
Summary & Conclusion
161
High-grade DCIS more frequently manifests as an
enhancing mass than does intermediate or low-grade DCIS.
Low-grade DCIS frequently shows non masslike enhancement
or no enhancement.
Two distinct patterns of neovascularization may occur in
DCIS: periductal and stromal. The periductal pattern manifests
as a dense rimlike network of micro-vessels adjacent to the
basement membrane of a duct. The stromal pattern is
characterized by a more diffuse increase in vascularity of the
stroma between DCIS lesions.
There is wide variability in the reported enhancement
kinetic curve of DCIS, with the most common pattern being
early enhancement with plateau kinetics, the plateau
enhancement kinetic curve is more commonly seen than
washout or progressive enhancement kinetics.
No kinetic pattern is pathognomonic of a particular
nuclear grade of DCIS.
Thus, the image interpretation and final recommendations
should be based on the morphologic characteristics instead of
the enhancement kinetics of the lesion.
Summary & Conclusion
161
Diffusion-weighted MRI (DWI) is an unenhanced MRI
sequence that has shown promise for discriminating benign
from malignant breast lesions and may yield information
different from and complementary to that obtained with DCEMR.
Pure DCIS lesions have higher signal intensity on DWI
than normal breast tissue and have a lower mean ADC value
than normal breast tissue. Non high grade lesions exhibit
greater DWI signal intensity and DWI CNR than high grade
lesions.
MR spectroscopy appears to have a bright future in the
field of breast imaging. Its role in differentiating benign from
malignant lesions and in improving the specificity of breast
MR imaging may result in fewer breast biopsies.
Some means of MR imaging–guided biopsy is essential in
a screening program to maximally benefit its sensitivity.
Thus, the role of MRI in the evaluation of ductal
carcinoma in situ (DCIS) has focused on two specific clinical
applications. The first is the performance of MRI in the
evaluation of the extent of the disease in patients with a
diagnosis of DCIS, before therapeutic planning. The second
Summary & Conclusion
161
application is early detection of DCIS in breast cancer
screening programs. These studies have focused on patients at
high risk for breast cancer in whom both mammography and
MRI are recommended for screening.
Conclusion:
The ability of MRI to detect the presence and extent of
DCIS In unequivocally significantly exceeds that of mammography
or ultrasound and is associated with acceptable
specificity. This improved sensitivity is particularly robust for
high-grade DCIS lesions. The improved diagnostic accuracy
will affect outcomes in patients at risk for and with breast
cancer warrants carefulinvestigation.