Quantitative assessment of nipple perfusion with near-infrared fluorescence imaging

Abstract

Preserving the nipple-areolar complex with a nipple-sparing mastectomy improves cosmesis compared with skin-sparing mastectomy. However, complications such as necrosis of the nipple-areolar complex significantly affect cosmetic outcome. Many factors influence nipple-areolar perfusion, and no consensus currently exists on optimal incisional choice. This study evaluates 2 nipple-sparing mastectomy incision models using near-infrared fluorescence to assess perfusion quantitatively. The periareolar and radial incisions were compared with 2 control models in Yorkshire pigs (N = 6). Methylene blue and indocyanine green were injected intravenously, and near-infrared fluorescence images were recorded at 3 time points: before surgery, immediately after (0 hour), and 3 days postoperatively. Contrast-to-background ratio was used to assess perfusion. At 72 hours, radial incisions showed a statistically significantly higher perfusion compared with periareolar incisions (P < 0.05). Based on our findings, radial incisions for nipple-sparing mastectomy may be preferable due to higher perfusion; however, clinical trials are necessary for further assessment.

Figures

Figure 1. Schematic drawings of the surgical models

Skin incision schemas are shown. Surgery was not performed on the control nipple (N). In Model 1 (pedicle circumareolar), the underlying pedicle and perforators were preserved. In Model 2 (periareolar incision) and Model 3 (radical incision), perforators were dissected and wide undermining was performed.

Figure 2. NIR imaging of blood flow, nipple, and skin during the arterial phase of NIR fluorophore administration

10 ml of MB solution (0.14 mg/kg) or 10 ml of ICG (0.018 mg/kg) was injected as a rapid bolus into the external jugular vein. The images are obtained preoperatively (top row), at the end of surgery: 0 h (middle row), and at 72 h (bottom row). At 72 h, Model 2 shows skin necrosis around nipple (arrow). Shown are the color video (left), the 700 nm NIR fluorescence from MB (middle; FLARE NIR channel #1), and the 800 nm NIR fluorescence from ICG (right; FLARE NIR channel #2). Ctrl: Control, M-1: Model 1, M-2: Model 2, M-3: Model 3. Scale bar = 3 cm.

Figure 3. Quantitative assessment of nipple imaging using NIR fluorescence

Direct comparison of CBR (mean ± SEM) between different fluorophores (MB and ICG) or all models (black line, control; red line, model 1; green line, model 2; and blue line, model 3) using MB (upper left, preoperative; lower left, 0 h; and lower right, 72 h) and ICG (upper right, preoperative). The statistical assessment was from linear mixed effects models with variance-covariance structure of compound symmetry. P values for the indicated statistical comparisons are as follows: * = P < 0.05.