Pulmonary imaging with a scanning acoustic microscope discriminates speed-of-sound and shows structural characteristics of disease.

Tissue elasticity can be detected using a scanning acoustic microscope (SAM), whereby acoustic images are created from the speed of sound through tissues. This system discriminated pulmonary tissue components and demonstrated distinct acoustic images of the lung; these results corresponded well to those obtained using the conventional microscope. SAM provides the following benefits: (1) images are acquired in only few minutes without requirement for staining, (2) basic data is obtained for low-frequency ultrasonic examination, and (3) speed of sound from each lesion is digital and comparable among diseases. Comparative analysis of cancer invasion, post-inflammatory fibrosis, and deposition disease was possible using the data obtained with the system, and the results showed good correlation with those using the conventional microscope and by clinical diagnosis. The SAM system is applicable not only to pulmonary diseases but also to various diseases in other organs.