A multispectral medical imaging device comprising: a plurality of illumination devices arranged to illuminate a target tissue, the plurality of illumination devices configured to emit light of different near-infrared wavelength bands; an objective lens; a near-infrared image sensor positioned to sequentially capture image frames reflected from the target tissue through the objective lens; a visible-light image sensor positioned to capture image frames reflected from the target tissue through the objective lens; an image capture buffer to store the image frames sequentially captured by the near-infrared image sensor and the image frames captured by the visible-light image sensor; a processor connected to the near-infrared image sensor, the visible-light image sensor, and the plurality of illumination devices, the processor configured to modulate near-infrared light output of the plurality of illumination devices to illuminate the target tissue, perform rolling processing on the image frames sequentially captured by the near-infrared image sensor that are stored in the image buffer to form output frames, each output frame comprising a combination of image frames sequentially captured by the near-infrared image sensor for each one of the different near-infrared wavelength bands emitted by the near-infrared sensor; determine reflectance intensities from the image frames captured by the near-infrared image sensor, wherein each image frame corresponds to illumination of the target tissue by one of the different near-infrared wavelength bands; and apply an oxygen saturation computation to the reflectance intensities to generate a dynamic tissue oxygen saturation map of the target tissue using the reflectance intensities; and an output device connected to the processor for displaying the dynamic tissue oxygen saturation map. a plurality of illumination devices arranged to illuminate a target tissue, the plurality of illumination devices configured to emit light of different near-infrared wavelength bands; an objective lens; a near-infrared image sensor positioned to sequentially capture image frames reflected from the target tissue through the objective lens; a visible-light image sensor positioned to capture image frames reflected from the target tissue through the objective lens; an image capture buffer to store the image frames sequentially captured by the near-infrared image sensor and the image frames captured by the visible-light image sensor; a processor connected to the near-infrared image sensor, the visible-light image sensor, and the plurality of illumination devices, the processor configured to modulate near-infrared light output of the plurality of illumination devices to illuminate the target tissue, perform rolling processing on the image frames sequentially captured by the near-infrared image sensor that are stored in the image buffer to form output frames, each output frame comprising a combination of image frames sequentially captured by the near-infrared image sensor for each one of the different near-infrared wavelength bands emitted by the near-infrared sensor; determine reflectance intensities from the image frames captured by the near-infrared image sensor, wherein each image frame corresponds to illumination of the target tissue by one of the different near-infrared wavelength bands; and apply an oxygen saturation computation to the reflectance intensities to generate a dynamic tissue oxygen saturation map of the target tissue using the reflectance intensities; and an output device connected to the processor for displaying the dynamic tissue oxygen saturation map.