In vitro feasibility of next generation non-linear beamforming ultrasound methods to characterize and size kidney stones

• Published in: Urolithiasis Vol. 47; no. 2; pp. 181 - 188
• Main Authors: Tierney, Jaime E., Schlunk, Siegfried G., Jones, Rebecca, George, Mark, Karve, Pranav, Duddu, Ravindra, Byram, Brett C., Hsi, Ryan S.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.04.2019; Springer Nature B.V
• Subjects: Algorithms; Feasibility Studies; Humans; Image Processing, Computer-Assisted - methods; Kidney - diagnostic imaging; Kidney Calculi - diagnostic imaging; Kidney stones; Medical Biochemistry; Medicine; Medicine & Public Health; Nephrology; Original Paper; Sensitivity and Specificity; Ultrasonic imaging; Ultrasonography - methods; Urogenital system; Urology; Kidney calculi; Kidney; Ultrasonography
• ISSN: 2194-7228; 2194-7236; 2194-7236
• DOI: 10.1007/s00240-018-1036-z

Ultrasound imaging for kidney stones suffers from poorer sensitivity, diminished specificity, and overestimation of stone size compared to computed tomography (CT). The purpose of this study was to demonstrate in vitro feasibility of novel ultrasound imaging methods comparing traditional B-mode to advanced beamforming techniques including plane wave synthetic focusing (PWSF), short-lag spatial coherence (SLSC) imaging, mid-lag spatial coherence (MLSC) imaging with incoherent compounding, and aperture domain model image reconstruction (ADMIRE). The ultrasound techniques were evaluated using a research-based ultrasound system applied to an in vitro kidney stone model at 4 and 8 cm depths. Stone diameter sizing and stone contrast were compared among the different techniques. Analysis of variance was used to analyze the differences among group means, with p  < 0.05 considered significant, and a Student’s t  test was used to compare each method with B-mode, with p  < 0.0025 considered significant. All stones were detectable with each method. MLSC performed best with stone sizing and stone contrast compared to B-mode. On average, B-mode sizing error ± SD was > 1 mm (1.2 ± 1.1 mm), while those for PWSF, ADMIRE, and MLSC were < 1 mm (− 0.3 ± 2.9 mm, 0.6 ± 0.8, 0.8 ± 0.8, respectively). Subjectively, MLSC appeared to suppress the entire background thus highlighting only the stone. The ADMIRE and SLSC techniques appeared to highlight the stone shadow relative to the background. The detection and sizing of stones in vitro are feasible with advanced beamforming methods with ultrasound. Future work will include imaging stones at greater depths and evaluating the performance of these methods in human stone formers.