Medical hyperspectral imaging to facilitate residual tumor identification during surgery.

INTRODUCTION: Adequate evaluation of breast tumor resection at surgery continues to be an important issue in surgical care, as over 30% of postoperative tumors recur locally unless radiation is used to destroy remaining tumor cells in the field. Medical Hyperspectral Imaging (MHSI) delivers near-real time images of biomarkers in tissue, providing an assessment of pathophysiology and the potential to distinguish different tissues based on spectral characteristics. METHODS: We have used an experimental DMBA-induced rat breast tumor model to examine the intraoperative utility of MHSI, in distinguishing tumor from normal breast and other tissues. Rats bearing tumors underwent surgical exposure and MHSI imaging, followed by partial resection of the tumors, then MHSI imaging of the resection bed, and finally total resection of tumors and of grossly normal-appearing glands. Resected tissue underwent gross examination, MHSI imaging, and histopathological evaluation. RESULTS: An algorithm based on spectral characteristics of tissue types was developed to distinguish between tumor and normal tissues. Tissues including tumor, blood vessels, muscle, and connective tissue were clearly identified and differentiated by MHSI. Fragments of residual tumor 0.5-1 mm in size intentionally left in the operative bed were readily identified. MHSI demonstrated a sensitivity of 89% and a specificity of 94% for detection of residual tumor, comparable to that of histopathological examination of the tumor bed (85% and 92%, respectively). CONCLUSION: We conclude that MHSI may be useful in identifying small residual tumor in a tumor resection bed and for indicating areas requiring more extensive resection and more effective biopsy locations to the surgeon.

The use of medical hyperspectral technology to evaluate microcirculatory changes in diabetic foot ulcers and to predict clinical outcomes.

OBJECTIVE: Foot ulceration is a serious complication of diabetes, and new techniques that can predict wound healing may prove very helpful. We tested the ability of medical hyperspectral technology (HT), a novel diagnostic scanning technique that can quantify tissue oxy- and deoxyhemoglobin to predict diabetic foot ulcer healing. RESEARCH DESIGN AND METHODS: Ten type 1 diabetic patients with 21 foot ulcer sites, 13 type 1 diabetic patients without ulcers, and 14 nondiabetic control subjects were seen up to 4 times over a 6-month period. HT measurements of oxyhemoglobin (HT-oxy) and deoxyhemoglobin (HT-deoxy) were performed at or near the ulcer area and on the upper and lower extremity distant from the ulcer. An HT healing index for each site was calculated from the HT-oxy and -deoxy values. RESULTS: Hyperspectral tissue oxygenation measurements observed changes in tissue immediately surrounding the ulcer when comparing ulcers that heal and ulcers that do not heal (P < 0.001). The sensitivity, specificity, and positive and negative predictive values of the HT index for predicting healing were 93, 86, 93, and 86%, respectively, when evaluated on images taken at the first visit. Changes in HT-oxy among the three risk groups were noted for the metatarsal area of the foot (P < 0.05) and the palm (P < 0.01). Changes in HT-deoxy and the HT healing index were noted for the palm only (P < 0.05 and P < 0.01, respectively). CONCLUSIONS: HT has the capability to identify microvascular abnormalities and tissue oxygenation in the diabetic foot and predict ulcer healing. HT can assist in the management of foot ulceration.