MR imaging-based Quantitative Analysis of Bladder Anatomy and Function in BPH/LUTS

摘要 在患有良性前列腺增生症和下尿路症状(BPH/LUTS)的男性中，膀胱收缩能力减弱是一个关键但没有得到很好解决的因素。我们建议验证这一假设，即MRI可以用于确定和量化BPH/LUTS患者膀胱解剖和排尿功能的具体变化。BPH手术包括切除增大的尿道周围前列腺组织，以减少排尿过程中的尿流阻力。然而，在许多BPH/LUTS患者中，膀胱收缩功能减弱，并极大地影响术后血流和排空的改善程度，与膀胱出口梗阻无关。在我们最近发表的研究中，我们使用基于MRI的成像来量化膀胱和前列腺解剖的指标，膀胱壁厚度和血流的区域差异。此外，我们发现，排尿过程中的实时成像结合计算模型可以量化膀胱收缩的指标，如逼尿肌缩短率和尿流动力学参数，如速度、压力和涡度。我们将使用它们来比较健康的年轻男性和患有BPH/LUTS的男性的膀胱排尿功能。我们将确定膀胱解剖的变化和损害排尿功能的具体机制，并描述每种机制对尿流量减少和膀胱排空障碍的相对贡献。这种基于MR图像的策略使用了已被广泛使用的技术来评估心血管功能。这项提议的新奇之处在于将这些技术应用于研究膀胱。据我们所知，从来没有人做过这样的事情。其科学影响是实施和验证MRI，以实现对健康的年轻男性和患有BPH/LUTS的男性下尿路解剖和功能的全面评估。磁共振成像获得的膀胱解剖和功能指标将在整个提案中得到验证，通过超声波确定的膀胱壁厚度和由多通道尿动力学确定的压力、流量、膀胱出口梗阻指数(BOOI)和膀胱收缩指数(BCI)等标准指标将得到验证。验证我们核磁共振技术的保真度对于临床实施至关重要。这些MRI协议可以使用大多数医院提供的标准MRI机器来实施。临床影响是，这些方法和经过验证的膀胱功能受损指标为医生提供了一种单一的非侵入性测试，同时描绘了下尿路的解剖和功能。这将使个性化的医学方法成为咨询和选择治疗的基础上，明确了解特定的解剖学特征和功能变化，损害个人的排尿的BPH/LUTS患者。

ABSTRACT Diminished bladder contractility is a critical but poorly addressed factor in men with benign prostatic hyperplasia and lower urinary tract symptoms (BPH/LUTS). We propose to test the hypothesis that MRI can be used to identify and quantify specific changes in bladder anatomy and voiding function in men with BPH/LUTS. BPH surgery involves removal of enlarged peri-urethral prostate tissue to reduce resistance to urine flow during the voiding effort. However, diminished bladder contractility is present in many patients with BPH/LUTS and greatly influences the degree of improvement of flow and emptying postoperatively, independent of bladder outlet obstruction. In our recently published studies, we used MRI based imaging to quantify metrics of bladder and prostate anatomy, regional differences in bladder wall thickness, and blood flow. Further, we showed that real-time imaging during voiding combined with computational modeling can quantify metrics of bladder contraction such as the rate of detrusor muscle shortening and urinary flow dynamics parameters such as velocity, pressure, and vorticity. We will use these to compare bladder voiding function in healthy young men and men with BPH/LUTS. We will identify changes in bladder anatomy and the specific mechanisms that impair voiding function and delineate the relative contribution of each mechanism to reduced urine flow and impaired bladder emptying. This MR image-based strategy employs techniques that have been used extensively to assess cardiovascular function. The novelty of the proposal is the adaptation of these techniques to study the bladder. To our knowledge, nothing like it has ever been done. The scientific impact is the implementation and validation of MRI to achieve comprehensive assessment of lower urinary tract anatomy and function in healthy young men and men with BPH/LUTS. Metrics of bladder anatomy and function obtained by MRI will be validated throughout the proposal with measurement of bladder wall thickness determined by ultrasound and the canonical metrics of pressure, flow, bladder outlet obstruction index (BOOI), and bladder contractility index (BCI) determined by multi-channel urodynamics. Validation of the fidelity of our MRI techniques is critical for clinical implementation. These MRI protocols can be implemented using standard MRI machines available in most hospitals. The clinical impact is that these methods and validated metrics of normal and impaired bladder function provide physicians with a single, non-invasive test that simultaneously delineates both anatomy and function of the lower urinary tract. This will enable a personalized medicine approach to counseling and selection of treatment based upon a clear understanding of the specific anatomic features and functional changes that impair voiding in individual patients with BPH/LUTS.