Ultrasound Shear Wave Elastography: A Novel Method to Evaluate Bladder Pressure

Sturm, R. M.; Yerkes, E. B.; Nicholas, J. L.; Snow-Lisy, D.; Diaz Saldano, D.; Gandor, P. L.; Halline, C. G.; Rosoklija, I.; Rychlik, K.; Johnson, E. K.; Cheng, E. Y.

J Urol. 2017 Apr 4

Abstract

PURPOSE: Children with bladder dysfunction leading to increased storage pressure are at risk for renal deterioration. The current gold standard evaluation is urodynamics, an invasive test requiring catheterization. The aim of this study was to evaluate ultrasound shear wave elastography (SWE) as a novel means to assess bladder biomechanical properties associated with elevated bladder pressure. METHODS: Concurrent SWE and urodynamics were performed. Ultrasound SWE images were obtained of the anterior and posterior wall when empty, at 25, 50, 75, 100% expected bladder capacity (EBC) and end fill volume. Regions of interest were confirmed by a pediatric radiologist. Bladder cohorts were defined as compliant (capacity detrusor pressure <25cm/H20) versus noncompliant (>/=25). Pearson correlation coefficients and mixed effects model evaluated the relationship between shear wave speed (SWS) and intravesical pressure, compliance and normalized compliance. An unpaired t-test was utilized for between cohort analyses. RESULTS: In all 23 subjects, mean SWS of the anterior and posterior bladder walls significantly correlated with pressure throughout filling. When comparing compliant versus noncompliant bladders, mean SWS and detrusor SWS of the anterior wall significantly increased with filling of noncompliant bladders; SWS remained at baseline levels in compliant bladders. Mean SWS of the anterior wall was significantly correlated with compliance and normalized compliance. CONCLUSIONS: Ultrasound SWE bladder measurements correlate well with bladder pressures, and SWS measurements differ in compliant versus non-compliant bladders. This is the first study to demonstrate that SWE is promising as a bedside modality for the assessment of bladder dysfunction in children.

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