Correlations Between B-Mode Ultrasonic Image Texture Features and Tissue Temperature in Microwave Ablation

Abstract

The purpose of this study was to find the correlations between B-mode ultrasonic tissue texture features and tissue temperature in microwave ablation. A total of 20 in vitro porcine liver samples were used for microwave ablation experiments. B-mode ultrasonic images under various temperatures were acquired. The texture features of the differential images based on the gray level histogram, including the mean of the gray scale (MGS), standard deviation of the gray scale, and entropy of the gray scale (ENT), and those based on the gray level co-occurrence matrix, including the contrast (CON), angular second moment (ASM), inverse difference moment (IDM), and correlation, were extracted. Correlations between the features and liver sample temperature were analyzed. In addition, water bath heating experiments were also performed on 15 in vitro porcine liver samples for analysis validation. The correlation coefficients across the MGS, ENT, and ASM in 4 directions (0°, 45°, 90°, and 135°), the CON and IDM in 3 directions (45°, 90°, and 135°), and a temperature range of 15°C to 90°C were high and greater than 0.9 during microwave ablation. All texture features of the differential B-mode ultrasonic images changed with rising temperature from 25°C to 60°C during water bath heating. Changes in image features reflect changes in tissue temperature during microwave ablation.