Visualization of myocardial cellular architecture using acoustic microscopy

The resolution of an ultrasound transducer depends on its frequency. The resolution improves when higher frequency transducers are used. A 1000 MHz transducer has a resolution of approximately 1 μm. Acoustic microscopy utilizes very high-frequency ultrasound (600 to 1000 MHz) to visualize structures on a microscopic level. Unstained, deparaffinized, 5 μm sections of myocardial biopsy specimens from 10 patients were placed on a slide and imaged using an Olympus UH3 scanning acoustic microscope. To compare with light microscopy, the section used for acoustic microscopy was subsequently stained with hematoxylin and eosin and a serial section from the paraffin block was stained with PTAH stain. Myocytes, myofibrils, and interstitial tissue were accurately imaged. Pathologic phenomena such as cell fallout, interstitial fibrosis, and lymphocytic infiltration were identified by acoustic microscopy. Intramural vessels, nuclei of endothelial cells, and the media were clearly identified by this technique. There was close correlation between findings by acoustic microscopy and light microscopy. Acoustic microscopy permitted the visualization of cardiac cellular detail with a resolution similar to that of light microscopy. Unlike light microscopy, acoustic microscopy requires no staining of the specimen.