Harmonic imaging is a widely utilized technique in abdominal ultrasonography due to its ability to reduce ultrasound artifacts. In this study, a novel version of harmonic ultrasound software, 3rd Harmonic Imaging, (3HLI), is compared to an earlier harmonic imaging version (d5.5i) to quantify user image detectability of tubular/liquid organ structures in the abdominal cavity between operators. A retrospective analysis was performed on a Canon ultrasound scanner (Aplio i800). In B- mode ultrasound, image quality was assessed by pixel intensity (histogram) and Contrast-to-Noise Ratio (CNRs) measurements. Regions of Interest (Target ROIs) included the lumen of common bile duct, gall bladder, and portal vein which were compared against Reference ROI, the liver parenchyma. Images acquired using both 3HLI and d5.5i software were analyzed across three different operators using a paired two-tailed paired t-test. 37 total pairs (3Hii and d5.5i) of B-mode ultrasound images were analyzed. A t-test was conducted to compare pixel intensity mean (M) and standard deviation (SD) of the Target ROI and Reference ROI. Contrast-to-Noise-Ratio (CNR) was then analyzed between the two software platforms. At a 95% confidence interval, significant differences were observed in the Target ROI (mean and SD) and CNR (P < 0.001) but not the mean nor the SD in the Reference ROI. CNR of 3Hii was significantly higher than d5.5i. These findings suggest that 3HLI software provides convincing evidence for improved visibility of tubular/liquid structures compared to d5.5i. Improved operator visibility and lesion detectability via 3rd harmonic imaging may provide greater diagnostic accuracy and patient outcomes. Though large-scale prospective studies using 3HLI software are recommended to confirm its clinical significance.
