SnapshotNIR: a handheld multispectral imaging system for tissue viability assessment

Tissue survival depends on the hemoglobin in blood to deliver oxygen to support cellular respiration. Without oxygenated blood surrounding tissue dies. Oxygenated hemoglobin has a distinct visible – near infrared absorption spectrum compared to deoxygenated hemoglobin. A hand-held multispectral reflectance imaging device, SnapshotNIR, was designed to provide a measure of the relative attenuation of reflected light from oxygenated and deoxygenated hemoglobin. The device combines the use of near real-time image classification / segmentation and regression to effectively determine the ratio of oxygenated to deoxygenated hemoglobin in the superficial vascular bed being imaged. This measurement of hemoglobin oxygen saturation can help detect local deficits in oxygen delivery to tissue. This simple, hand-held, battery-powered imaging device can quickly survey large areas of tissue in a complete non-invasive fashion. It is easy to use and suitable for use in the operating room or clinics that have limited infrastructure. Examples are given on the performance of the device in general surgery and in the assessment of peripheral circulation.