Breast ImagingE2329. Breast MRI in Ductal Carcinoma in Situ With Emphasis on DWI
Porembka J, Kulkarni S, Dogan B. University of Texas Southwestern Medical Center, Dallas, TX
Address correspondence to J. Porembka (firstname.lastname@example.org)
Background Information: Ductal carcinoma in situ (DCIS) accounts for approximately 20% of all breast cancers. Mammography is the primary imaging modality used to identify, stage, and preoperatively guide the localization of pure DCIS. In select DCIS cases, however, mammography may be insufficient to evaluate for an associated occult invasive component, possible ipsilateral nipple involvement, and noncalcified multifocal and multicentric disease. Furthermore, there has been increasing identification of mammographically occult noncalcified DCIS with the more prevalent use of screening breast ultrasound in dense breasts and molecular breast imaging (MBI). Dynamic contrast-enhanced breast MRI (DCE MRI) used in conjunction with conventional imaging improves the accuracy of preoperative imaging and can alter surgical management in select cases of DCIS with nipple involvement and noncalcified multifocal and multicentric disease. However, DCE MRI has moderate-to-low specificity, and its routine use in patients with DCIS has not been associated with improved surgical outcomes. Advances in functional MRI such as DWI, an unenhanced MRI technique that measures the movement of water molecules in vivo, has led to its widespread use, and may help improve the specificity of breast MRI in patients with DCIS.
Educational Goals/Teaching Points: Goals for this exhibit are to understand the indications and role of preoperative breast MRI in the evaluation of selected cases of DCIS, recognize the characteristic imaging appearance of DCIS on DCE MRI and DWI, and distinguish DCIS extent from background parenchymal enhancement using DWI.
Key Anatomic/Physiologic Issues and Imaging Findings/Techniques: DCIS most commonly appears as nonmass enhancement in a ductal, linear, segmental, or regional distribution on DCE MRI. DCE MRI helps in surgical planning and in determining the eligibility of patients who are candidates for accelerated partial breast radiotherapy or nipple sparing surgery. Although there is overlap in DWI signal and apparent diffusion coefficient (ADC) values for benign and malignant lesions, breast malignancies typically have high cellular density related to cellular proliferation resulting in increased diffusion restriction and decreased ADC values compared to benign breast lesions and normal breast tissue. Using DWI to look for linear or regional areas of diffusion restriction can help to successfully determine DCIS extent in patients with significant background parenchymal enhancement.
Conclusion: First, In select cases of DCIS, DCE MRI is useful in preoperative planning. Preoperative DCE MRI can also help in the selection of patients who are eligible for accelerated partial breast irradiation or nipple-sparing mastectomy. Second, DCIS can be identified on DWI as a linear or regional area of diffusion restriction. Third, utilization of DWI as a stand-alone DCIS detection tool is still under investigation. Finally, future development of more evolved multichannel coils, ultrafast echoplanar imaging, and stronger gradients may help DWI utilization in lieu of DCE MRI for identification of DCIS.