Reductions in bladder compliance are common in spinal cord injured patients with neurogenic bladder and are associated with multiple adverse outcomes ranging from bothersome lower urinary tract symptoms to dangerously high detrusor storage pressures with the potential for renal failure. Cystometry, a component of Urodynamic Study (UDS) is the current gold standard for assessing bladder compliance, but these studies are invasive, expensive, time intensive, can be extremely uncomfortable, and carry a risk of clinical side effects. There is a need for the development of alternate, noninvasive methods for measuring bladder compliance. Such a method would be useful both clinically and for research. Thus, the goal of this study is to develop a noninvasive, quantitative, rapid, and sensitive method for evaluation of bladder wall elasticity where this information can be used to assess bladder compliance. To address this problem, we propose a technique called Ultrasound Bladder Vibrometry (UBV) for noninvasive assessment of bladder. This study includes the following two Specific Aims:
Aim 1. Estimate concordance between UBV measures and cystometry measures of bladder compliance. The general hypothesis in this Aim is the proposed UBV method can provide new, useful information that relates to bladder compliance in human subjects. To test this hypothesis, UBV will be performed on a select group of spinal cord injured neurogenic patients undergoing UDS. Results of elasticity measures by UBV will be used to correlate to the UDS measures of bladder compliance.
Aim 2. Evaluate the clinical value of UBV measures as a predictor of bladder non-compliance trend using a longitudinal study approach in patients with new spinal cord injury. The goal of this Aim is to test the hypothesis that viscoelastic parameters of the bladder and their variations versus bladder volume, as measured by UBV, can predate noncompliance or poor function of bladder. To test this hypothesis, a longitudinal study will be conducted in which UBV will be performed periodically on a group of new spinal cord injured patients who have compliant bladder but are at risk for developing non-compliant bladder, and for this reason, they are scheduled for periodic (annual or semiannual) bladder evaluations including UDS. Compiled UBV results will be compared against the clinical findings to determine if variations in UBV measures predict bladder dysfunction earlier than clinical findings. A positive outcome means that UBV can be used for early detection and hence enhanced treatment of bladder dysfunction. The proposed UBV method is novel, noninvasive, quantitative, fast, low cost, portable, and adaptable to current ultrasound technology with only software changes, all of which mean that this technique can be readily translated into clinical practice and become available to a large patient population worldwide. Additionally, this UBV provides a unique set of information about bladder that has not been available before. This information can potentially lead to earlier detection and improved management of bladder dysfunction. Thus, successful completion of this project may have a significant impact in diagnosis and management of bladder dysfunction.
Patients with spinal cord injury often develop a condition known as neurogenic bladder. These patients have changes to their bladder structure such that the bladder becomes noncompliant. For this reason, these patients must undergo frequent testing (known as cystometry) to make sure that life-threatening kidney conditions do not develop. Cystometry tests are invasive, uncomfortable, and expensive. In this study, we propose to develop and test a technique called Ultrasound Bladder Vibrometry as a safe, inexpensive, noninvasive tool for measuring bladder compliance.