Intraoperative video-rate hemodynamic response assessment in human cortex using snapshot hyperspectral optical imaging

Abstract

Intraoperative video-rate hemodynamic response assessment in human cortex using snapshot hyperspectral optical imaging," Neurophoton. Abstract. Using light, we are able to visualize the hemodynamic behavior of the brain to better understand neurovascular coupling and cerebral metabolism. In vivo optical imaging of tissue using endogenous chromophores necessitates spectroscopic detection to ensure molecular specificity as well as sufficiently high imaging speed and signal-to-noise ratio, to allow dynamic physiological changes to be captured, isolated, and used as surrogate of pathophysiological processes. An optical imaging system is introduced using a 16-bands on-chip hyperspectral camera. Using this system, we show that up to three dyes can be imaged and quantified in a tissue phantom at video-rate through the optics of a surgical microscope. In vivo human patient data are presented demonstrating brain hemodynamic response can be measured intraoperatively with molecular specificity at high speed.

Illumination-robust multispectral demosaicing

“…Multispectral images are acquired in different illumination conditions for various application fields such as medical imaging [1], precision agriculture [2], art studies [3], vision inspection for food quality control [4] or waste sorting [5]. The information available in each channel of a multispectral image results from a spectral integration of the product between the scene reflectance, illumination, camera filter transmittances and sensor sensitivity.…”

Intraoperative quantitative functional brain mapping using an RGB camera

“…The intrinsic signal refers to the cortical reflectance changes 14,17 due to hemodynamic response. A hyperspectral camera, 18,19 or a single-wavelength illumination in conjunction with a low-noise CCD camera, 16,20 can be used to acquire the intrinsic signal. The time course of this signal is characterized by the early hemodynamic responses in brain tissue related to neuronal activity (initial dip) followed by a larger response that corresponds to the BOLD signal in fMRI studies.…”

“…21,22 In some studies, a spectroscopic analysis of the intrinsic signal is computed to assess the cortical hemoglobin concentration changes. New approaches consist in using an RGB 21,23 or hyperspectral 18 camera with a continuous wave white light source 18,21,24 or pulsed narrow bandpass illumination sources. 23,25 These setups have the main advantages of being usable in real time 18,25 and directly in the operative room.…”

“…New approaches consist in using an RGB 21,23 or hyperspectral 18 camera with a continuous wave white light source 18,21,24 or pulsed narrow bandpass illumination sources. 23,25 These setups have the main advantages of being usable in real time 18,25 and directly in the operative room. Steimers et al 23 analyzed an exposed rat cortex with an RGB-LED light source and an RGB camera.…”

“…Inhomogeneities of the optical properties were not taken into consideration since an averaged path length provided by Monte-Carlo simulation was used in the model. Pichette et al 18 used a hyperspectral camera and continuous wave white light illumination to assess in real time the absorbance changes. In their study, the blood vessels and the gray matter pixels were automatically segmented by comparing measured reflectance spectra to blood and gray matter simulated reflectance spectra.…”