Breast vascular mapping obtained with contrast-enhanced MR imaging: implications for cancer diagnosis, treatment, and risk stratification

Abstract

The value of breast vascular maps obtained using contrast-enhanced MR imaging has recently been explored. Additional information is obtained only by evaluating maximum intensity projections of the first dynamic subtraction to achieve a form of MR angiography of the breast. No increase in acquisition time and no dedicated contrast injections are needed. Four studies have been performed to evaluate the one-sided (asymmetric) increase in vascularity associated with ipsilateral cancer in a total of 404 patients with a cancer prevalence ranging from 38% to 80%. Sensitivity ranged from 72% to 88%, specificity from 57% to 100%, positive predictive value from 85% to 100%, negative predictive value from 38% to 88%, and overall accuracy from 73% to 87%. An asymmetric increase in breast vascularity ipsilateral to a cancer may be due to reduced flow resistance in the tumour, to a high metabolic rate (more likely in large tumours) or to angiogenic stimulation of the whole breast harbouring the lesion (more likely in small tumours). Tumour size could play a specific role in determining the ipsilaterally increased vascularity, and invasive cancers might be more frequently associated with ipsilaterally increased vascularity than in situ cancers. Moreover, while a reduction in breast vasculature has anecdotically been observed in breasts with locally advanced cancers treated with neoadjuvant chemotherapy, especially when taxanes are used, the higher incidence of breast cancer in patients with size asymmetry between the breasts as determined on screening mammography suggests that a role for breast MR vascular mapping in breast cancer risk stratification should be explored. Finally, arteries and veins might be differentiated with dedicated techniques. High-relaxivity agents may be used with advantage in these future investigations.

Variation of Breast Vascular Maps on Dynamic Contrast-Enhanced MRI After Primary Chemotherapy of Locally Advanced Breast Cancer

“…In our study, before primary chemotherapy, we found an increased number of vessels in the breast harboring the cancer with respect to the contralateral one, confirming the results of previous studies [1][2][3][4][5][6]. Medical neoadjuvant treatments are aimed at downsizing the cancer and exploring the in vivo chemosensitivity of the tumor cells [10,11,15,16].…”

“…Future studies in this realm should include the introduction of computer-assisted software performing a standardized and highly reproducible quantification of breast vessels. Third, the temporal resolution of our technical protocol ranged between 60 and 90 seconds, in agreement with technical requirements recommended in the literature [22] and adequate for an angiographic study [1,3]. As a consequence, mixed arterial and venous vessels are also enhanced as a result of contrast material administration, which may be a study limitation.…”

“…More recently, several studies with DCE-MRI revealed a different whole-breast vasculature associated with malignancy as the result of a higher number of larger vascular structures identified in the breast harboring the cancer compared with the contralateral healthy breast [1][2][3][4][5][6].…”

“…As a consequence, our results should be considered as preliminary and require further investigation, including the study of the early predictive role of variations of vascular maps during primary chemotherapy. Second, the method adopted in our study to quantify the whole-breast vascular map [1], even though it was previously shown to give a diagnostic gain in breast lesion characterization [3,5,6], should be verified in terms of reproducibility. As a matter of fact, artifacts, especially those due to misregistration, may limit the vessel analysis.…”

Whole-body MRI: comprehensive evaluation on a 48-channel 3T MRI system in less than 40 minutes. Preliminary results

“…Our technique of breast MRI was limited because it did not include serial thin section imaging to generate enhancement curves. However it did show morphological detail, which is important for breast imaging (36) and also can reveal dilated veins that have been reported as consistently present in breast cancer (37) . It should also be feasible to add a more dedicated breast MR study, including a second injection of A B C D gadolinium contrast.…”