Liver fatty change classification using 25MHz high frequency ultrasound
Journal
Proceedings - IEEE Ultrasonics Symposium
Journal Volume
3
Pages
2169-2172
Date Issued
2004
Author(s)
Abstract
Liver fatty change (steatosis), the accumulation of fat within liver cells, is a common histological finding in liver biopsies. The histological changes of steatosis such as the distribution of fatty droplets cannot be resolved by conventional ultrasound. High frequency ultrasound (≧20 MHz), on the other hand, has the potential to reveal more detail of steatosis. In this study, B-mode images of high frequency ultrasound of 19 fresh human liver samples were obtained to evaluate ultrasound's ability in determining the steatosis grade. B-mode images were acquired by a mechanically controlled 25MHz single crystal probe. Image features derived from gray level concurrence and non-separable wavelet transform were extracted to classify steatosis grade using a classifier known as the support vector machine. Each liver sample subsequently underwent histological examination and liver steatosis was graded from 0 to 3 (0: no fatty change; 1: less than 33% of hepatocytes affected; 2: 33% to 66% of hepatocytes affected; and 3: more than 66% of hepatocytes affected). The four grades were then combined into 2 classes- grade 0 and grades 1-3 (non-steatosis and steatosis); 3 classes- grade 0, grade 1 and grades 2-3 (non-steatosis, mild steatosis, and prominent steatosis); and 4 classes (all different grades). Classification results were correlated with histology. It is shown that the best classification accuracy of 2, 3 and 4 classes were 90.5%, 85.8% and 82.6%, respectively. Compared with the results acquired from conventional ultrasound at 7 MHz (the best classification accuracy of 2, 3 and 4 classes were 81.6%, 75.8% and 74.2%, respectively), the classification accuracy was clearly better at 25 MHz. Thus, liver steatosis can be more accurately characterized using high frequency B-mode ultrasound. Limitations and potential solutions of liver steatosis using high frequency ultrasound are also discussed. ? 2004 IEEE.
SDGs
Other Subjects
B-mode images; High frequency ultrasounds; Liver cells; Liver fatty changes; Biopsy; Cells; Diseases; Histology; Image processing; Low pass filters; Mathematical models; Scanning; Tissue; Transducers; Vectors; Wavelet transforms; Ultrasonic imaging
Type
conference paper