H-scan ultrasound imaging for the preclinical assessment of liver cancer treatment with transarterial chemoembolization

H-scan ultrasound (US) is a new imaging technique based on a simplified framework for characterizing the relative size of acoustic scatterers and visualizing the results as a color overlay onto the registered B-scan US image. The purpose of this research was to explore H-scan US imaging of liver cancer-bearing animals after receiving transarterial chemoembolization (TACE) treatment. Radiofrequency (RF) data was collected using a preclinical US system (Vevo 3100, FUJIFILM VisualSonics Inc) integrated with a MX201 linear array transducer. US imaging was performed at a center frequency of 15 MHz with a single focal position. The H-scan US analysis involved use of two convolutional filters composed of 2nd and 8th-order Gaussian-weighted Hermite polynomial functions that were applied in parallel to the RF data sequence to assess the relative strength of the backscattered US signals. Filter outputs were combined and color coded to form the final H-scan US image. A total of nine Sprague-Dawley rats (Charles River Laboratories) were used in this study. All animals were imaged at baseline and one week after receiving TACE treatment. Texture analysis was also performed on the H-scan US images, and features such as contrast (CON), homogeneity (HOM), sum average (SA), and sum variance (SV) were projected onto spatial maps. Mean changes in H-scan US image intensity and textural parameters were quantified and compared with pathologically determined tumor response. Experimental results indicated that the SA feature significantly distinguished between the responder and non-responder TACE group animals. Overall, H-scan US imaging with texture analysis has the potential to improve detection of early liver cancer response to TACE treatment.