Assessment of Breast Tumors Using Multispectral Optoacoustic Tomography in a Surgical Setting

In breast-conserving surgery, wire or seed localization and ultrasound are limited by lack of margin detection and contrast imaging, respectively. Handheld multispectral optoacoustic tomography (MSOT) allows for contrast imaging using endogenous or exogenous agents. This trial evaluated the safety and performance of MSOT for imaging breast masses intraoperatively. Methods: Imaging with MSOT was performed on 45 women preoperatively and postoperatively. The temperature and appearance of the skin were recorded before and after imaging. Levels of deoxyhemoglobin, oxyhemoglobin, total hemoglobin, and microvascular oxygen saturation were recorded for malignant and benign breast tissue using MSOT. In patients undergoing sentinel lymph node biopsy, the ipsilateral axilla was imaged with MSOT. For analysis, patients were categorized by Fitzpatrick skin type. Results: All breast masses were successfully imaged as cancers using MSOT. In preoperative and postoperative imaging, patients' skin temperatures did not exceed 37 °C, and no adverse effects were observed after imaging across all Fitzpatrick skin types. The findings in breast tumor images using deoxyhemoglobin (mean, 0.0782), oxyhemoglobin (mean, 0.0833), and total hemoglobin (mean, 0.161) were each significantly different from those of contralateral breast presurgery (P < 0.0001). Microvascular oxygen saturation did not significantly differ between breast tumors and contralateral breast tissue (P = 0.704). The average imaging time before and after surgery was 3 min. No adverse events were recorded. All 3 positive sentinel lymph nodes identified intraoperatively using isosulfan blue injection were successfully imaged by MSOT preoperatively, and no false-positives were obtained with MSOT. Conclusion: MSOT is safe for use in image-guided breast cancer detection and has not been shown to increase patient skin temperature. MSOT can successfully distinguish between cancer and benign tissue using endogenous contrast agents and identify sentinel lymph nodes using isosulfan blue.