Speed of sound in diseased liver observed by scanning acoustic microscopy with 80 MHz and 250 MHz

Abstract

In this study, the speed of sound (SOS) of two types of rat livers (eight normal livers, four cirrhotic livers) was measured with a scanning acoustic microscope using two transducers, one of which had an 80-MHz and the other a 250-MHz center frequency. The 250-MHz transducer had a better spatial resolution adapted to studying fiber or hepatic parenchymal cells. In normal livers, averages of the SOS values were from 1598 to 1677 m/s at 80-MHz and from 1568 to 1668 m/s at 250-MHz. In the fiber tissue of cirrhotic livers, averages of the SOS values were from 1645 to 1658 m/s at 80-MHz and from 1610 to 1695 m/s at 250-MHz, while the SOS values in the other tissue of cirrhotic livers ranged from 1644 to 1709 m/s at 80-MHz and from 1641 to 1715 m/s at 250-MHz. In one liver, SOS in fiber tissue was larger than that of tissues without fiber while in others it was lower. The resulting two-dimensional SOS maps provide a unique quantitative insight of liver acoustic microstructures in a healthy liver and in a cirrhotic ones. This study would be helpful to understand the complex relationship between acoustic properties and liver disease including fiber tissue.

Approximate Message Passing Reconstruction of Quantitative Acoustic Microscopy Images

“…To date, our group and others have successfully used QAM to investigate a wide range of soft biological tissues such as liver samples, lymph nodes, retina, and even living cells [1]- [5]. Several of these recent studies were performed using QAM systems equipped with spherically focused single-element transducers having center frequencies of 250 MHz or 500 MHz which yielded 2D maps of acoustic properties with spatial resolutions of 7 and 4 µm, respectively [2], [3]. Currently, QAM requires a complete 2D raster scan of the sample to form images, thus yielding a large amount of RF data when using a conventional spatial sampling scheme (e.g., 2 and 1 µm steps at 250 and 500 MHz, respectively).…”

Examination of Cerebral Aneurysm by Scanning Acoustic Microscopy

“…Ultrasound signals are used to define the elastic properties of biological tissues by calculating sound speed through tissues [7-9] or acoustic impedance of the tissues [10]. When compared with the techniques previously mentioned, SAM has the advantage of micro-meter level resolution, the capability of non-destructive monitoring, no requirement of a special sampling, the ability of quick measurement (less than 2 minutes for a 4.8 mm x 4.8 mm area) [11] and the applicability to tissues [12][13][14][15] or cell populations [16][17][18][19][20]. Besides, a SAM probe would enable its use in clinics [21].…”

Improved High-Frequency Ultrasound Corneal Biometric Accuracy by Micrometer-Resolution Acoustic-Property Maps of the Cornea

“…SAM has been applied successfully to characterize various soft tissues such as skin, coronary artery, lymph node, prostate, tendon, liver, and muscle tissue. 12 – 20 However, very few studies have reported SAM measurements for ocular tissues. 21 – 23 Using SAM, Beshtawi et al 21 found a 5% increase of speed of sound of cross-linked corneal tissue compared to cryosectioned corneas and found good agreement between histology and speed of sound in the treated cases.…”