In vivo integrated photoacoustic and confocal microscopy of hemoglobin oxygen saturation and oxygen partial pressure

摘要

We developed dual-modality microscope integrating photoacoustic microscopy (PAM) and fluorescence confocal microscopy (FCM) to noninvasively image hemoglobin oxygen saturation (sO_(2)) and oxygen partial pressure (pO_(2)) in vivo in single blood vessels with high spatial resolution. While PAM measures sO_(2) by imaging hemoglobin optical absorption at two wavelengths, FCM quantifies pO_(2) using phosphorescence quenching. The variations of sO_(2) and pO_(2) values in multiple orders of vessel branches under hyperoxic (100percent oxygen) and normoxic (21percent oxygen) conditions correlate well with the oxygen-hemoglobin dissociation curve. In addition, the total concentration of hemoglobin is imaged by PAM at an isosbestic wavelength.