A multispectral medical imaging device includes illumination devices arranged to illuminate target tissue. The illumination devices emit light of different near-infrared wavelength bands. The device further includes an objective lens, a near-infrared image sensor positioned to capture image frames reflected from the target tissue, and a visible-light image sensor positioned to capture image frames reflected from the target tissue. A processor is configured to modulate near-infrared light output of the plurality of illumination devices to illuminate the target tissue. The processor is further configured to determine reflectance intensities from the image frames captured by the near-infrared image sensor and to generate a dynamic tissue oxygen saturation map of the target tissue using the reflectance intensities. The device further includes an output device connected to the processor for displaying the dynamic tissue oxygen saturation map.