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

摘要 膀胱收缩力下降是良性前列腺增生和下尿路症状（BPH/LUTS）男性的一个关键因素，但解决得不好。我们建议测试的假设，MRI可以用来识别和量化的具体变化，膀胱解剖结构和排尿功能的男性BPH/LUTS。BPH手术包括切除尿道周围增大的前列腺组织，以减少排尿过程中对尿流的阻力。然而，许多BPH/LUTS患者存在膀胱收缩力减弱，并极大地影响了术后流量和排空的改善程度，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结构、膀胱壁厚度和血流的区域差异的指标。此外，我们表明，排尿期间的实时成像结合计算建模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。我们将使用这些来比较健康年轻男性和BPH/LUTS男性的膀胱排尿功能。我们将确定膀胱解剖结构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受损的相对贡献。这种基于MR图像的策略采用了已广泛用于评估心血管功能的技术。该提案的新奇在于将这些技术用于研究膀胱。据我们所知，从来没有这样做过。其科学影响是MRI的实施和验证，以实现对健康年轻男性和BPH/LUTS男性下尿路解剖结构和功能的全面评估。通过MRI获得的膀胱解剖结构和功能的测量将在整个提案中通过超声确定的膀胱壁厚度的测量以及通过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）的规范度量进行验证。验证我们的MRI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中可用的标准MRI机器来实现。临床影响是，这些方法和经验证的正常和受损膀胱功能的指标为医生提供了一个单一的，非侵入性的测试，同时描绘下尿路的解剖结构和功能。这将使个性化的医疗方法，咨询和选择治疗的基础上，明确了解具体的解剖特征和功能变化，损害排尿的个体患者与BPH/LUTS。

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.