Photoacoustic imaging of the microvasculature with a high-frequency ultrasound array transducer.

Visualization of microvascular networks could provide new information about function and disease. We demonstrate the capabilities of a 30-MHz ultrasound array system for photoacoustic microscopy of small (< or = 300 microm) vessels in a rat. 3D images obtained by translating the array in the elevation direction are compared with photographs of excised skin. The system is shown to have 100-microm lateral resolution, 25-microm axial resolution, and 3-mm imaging depth. To our knowledge this is the first report on photoacoustic microscopy of the microvasculature with a high-frequency array transducer. It is anticipated that the system can be used for studying and diagnosing a number of diseases including cancer, atherosclerosis, dermatological disorders, and peripheral microvascular complications in diabetes.