A confocal microscope for nondestructive quantification of microvascular flow

To quantify the effects of biomaterial implants on the local microvasculature, an imaging system is needed to nondestructively measure blood flow, in vivo, in three dimensions. To meet this need a confocal microscope was built based on the Texas Instruments Digital Micromirror Device (DMD). The DMD confocal microscope operates by simultaneously scanning a multitude of confocal spots in the specimen plane thus achieving high pixel dwell time and thus requiring lower light power. The lower light power permits nondestructive imaging of live tissue. The 3-D resolution of the microscope was quantified for in vivo scanning in thick tissue. Image processing and cell tracking algorithms were implemented to measure flow velocities of fluorescently labeled erythrocytes in thin optical sections. The resulting 3-D blood flow data was used to measure perfusion at various depths from implants in hamster dorsal skin fold chambers.