Visible Reflectance Hyperspectral Imaging:  Characterization of a Noninvasive, in Vivo System for Determining Tissue Perfusion

• Published in: Analytical chemistry (Washington) Vol. 74; no. 9; pp. 2021 - 2028
• Main Authors: Zuzak, Karel J, Schaeberle, Michael D, Lewis, E. Neil, Levin, Ira W
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.05.2002
• Subjects: Biological and medical sciences; Blood Gas Monitoring, Transcutaneous - instrumentation; Blood Gas Monitoring, Transcutaneous - methods; Cell physiology; Chemistry; Diagnostic Equipment; Erythrocytes - chemistry; Fundamental and applied biological sciences. Psychology; Hand - blood supply; Hemerythrin - analogs & derivatives; Hemerythrin - analysis; Humans; Hyperemia - blood; Hyperemia - diagnosis; Image Processing, Computer-Assisted; Ischemia - blood; Ischemia - diagnosis; Light sources; Medical research; Miscellaneous; Models, Cardiovascular; Molecular and cellular biology; Oxyhemoglobins - analysis; Reperfusion; Spectrum Analysis; Tungsten; Hyperspectral imaging sensor; Tissue; Investigation method; Imagery; Perfusion
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac011275f

We characterize a visible reflectance hyperspectral imaging system for noninvasive, in vivo, quantitative analysis of human tissue in a clinical environment. The subject area is illuminated with a quartz−tungsten−halogen light source, and the reflected light is spectrally discriminated by a liquid crystal tunable filter (LCTF) and imaged onto a silicon charge-coupled device detector. The LCTF is continuously tunable within its useful visible spectral range (525−725 nm) with an average spectral full width at half-height bandwidth of 0.38 nm and an average transmittance of 10.0%. A standard resolution target placed 5.5 ft from the system results in a field of view with a 17-cm diameter and an optimal spatial resolution of 0.45 mm. The measured reflectance spectra are quantified in terms of apparent absorbance and formatted as a hyperspectral image cube. As a clinical example, we examine a model of vascular dysfunction involving both ischemia and reactive hyperemia during tissue reperfusion. In this model, spectral images, based upon oxyhemoglobin and deoxyhemoblobin signals in the 525−645-nm region, are deconvoluted using a multivariate least-squares regression analysis to visualize the spatial distribution of the percentages of oxyhemoglobin and deoxyhemoglobin in specific skin tissue areas.