MRI in pre-operative NAC vascular map

Abstract

Objective: NAC’s blood supply may convey essential information for surgery planning. This study’s aim was to evaluate breast blood supply using MRI and to compare it between oncological and non-oncological subjects. The risk factors for NAC necrosis in nipple sparing mastectomy were analyzed. Methods: Breast MRI exams in one month at a single institution were evaluated. The considered inclusion criteria focused on patients with: ductal carcinoma in situ, invasive carcinoma (IC) or high-risk screening (HRS) without previous breast surgery. Subtraction reconstructions from dynamic acquisitions obtained at 60 s post-contrast administration were used. Results: 166 breasts were evaluated (12 pre op DCIS; 42 HRS; 112 pre op IC) - 71% of the NAC’s had a dominant blood supply. Tumors were localized in the upper outer quadrant (UOQ) in 46% of cases. In the NAC vascularization analysis, there was a tendency for a higher number of vessels vascularizing the NAC in the IC group (p=0.056) and there was a difference in the quadrant analysis mainly at the UOQ that had a dominant blood supply in 18% of the IC group and only 2% in the HRS (p=0.048). 16 patients performed NSM, three had NAC necrosis. The number of vessels supplying the NAC was the only factor with correlation with this outcome (p=0.01). There was not a single NAC with a dominant blood vessel from the lower outer quadrant (LOQ). Conclusion: Using MRI to pre-operatively evaluate breast blood supply is feasible without adding extra MRI time or contrast. 71% had dominant supply to the NAC, so every effort should be made to preserve it. The LOQ appears to be an optimal site for skin incisions. There is an asymmetry between cancer and HRS breasts mainly at the NAC’s level with neovascularization of that area. Patients with a single vessel supplying the NAC are at improved risk for necrosis.