Second-Generation Differential Tissue Harmonic Imaging Improves the Visualization of Renal Lesions

Objectives To compare to three nonlinear imaging techniques to conventional, grayscale ultrasound imaging of renal lesions. Methods Twenty adults with a known renal lesion and a body mass index >25 kg/m(2) were enrolled in this prospective, institutional review board approved study. Each subject was imaged with an Aplio 500 scanner (Canon Medical Systems, Tokyo, Japan) using grayscale ultrasound, tissue harmonic imaging (THI) and two dual-frequency, differential tissue harmonic imaging modes (DTHI and DTHI-II, respectively). In total 184 images were scored by three independent and blinded observers for detail resolution, image quality, margin delineation, and depth penetration. Quantitative contrast-to-noise ratios (CNRs) were also calculated. Results Readers and CNR values showed that nonlinear imaging was superior to grayscale ultrasound (P < .0014). DTHI-II outperformed DTHI, THI, and grayscale ultrasound with respect to detail resolution, image quality, and margin delineation (P < .012). The depth penetration of DTHI and DTHI-II was similar (P = .16), but superior to grayscale ultrasound and THI (P < .001). Two observers saw improvements in detail resolution with DTHI-II over DTHI (P < .05), while image quality and margin delineation were considered similar by two readers (P > .07) and improved with DTHI-II by one (P < .017). Conclusions DTHI-II improves the imaging of renal lesions compared to DTHI, THI, and grayscale ultrasound, albeit based on a limited sample size.