Nagle Anna S, Cullingsworth Zachary E, Li Rui, Carucci Laura R, Klausner Adam P, Speich John E
Department of Mechanical & Nuclear Engineering, Virginia Commonwealth University College of Engineering Richmond, VA, USA.
Department of Radiology, Virginia Commonwealth University School of Medicine Richmond, VA, USA.
Am J Clin Exp Urol. 2021 Feb 15;9(1):44-52. eCollection 2021.
Rhythmic contractions of the bladder wall during filling result from the synchronization of bladder wall micromotion and are often observed in the urodynamic tracings of individuals with urinary overactive bladder (OAB). This study's objective was to develop a novel, non-invasive method to measure bladder wall micromotion and to conduct an initial study to test the hypothesis that elevated micromotion is associated with OAB.
This prospective study enrolled women with OAB and asymptomatic volunteers as measured by the ICIQ-OAB survey. After filling the bladder to 40% cystometric capacity, 85 second cine-loops were obtained using a GE Voluson E8 ultrasound system with an 8 MHz curved, abdominal probe. A custom correlation-based texture tracking MATLAB algorithm was used to measure changes in the bladder wall thickness over time and correlate with changes in vesical pressure. Significant bladder wall micromotion was defined as changes in wall thickness with amplitudes higher than 0.1 mm in the frequency range of 1.75-6 cycles/minute as calculated from Fast Fourier Transform (FFT) analysis. The micromotion algorithm was tested on 30 women including 17 with OAB and 13 asymptomatic volunteers.
Micromotion was identified in 41% of subjects with OAB and 0% of asymptomatic volunteers, indicating a significant association of micromotion with OAB (Fisher's exact test, P=0.010). Micromotion was also found to have a significant association with a clinical diagnosis of detrusor overactivity (Fisher's exact test, P=0.031). Frequencies with elevated micromotion correlated with frequencies of vesical pressure fluctuations.
The feasibility of a non-invasive method to measure bladder wall micromotion was demonstrated using transabdominal anatomical motion mode (M-mode) ultrasound. Presence of micromotion was significantly associated with OAB and with urodynamic-identified rhythm.
膀胱充盈期间膀胱壁的节律性收缩源于膀胱壁微运动的同步，且常在膀胱过度活动症（OAB）患者的尿动力学描记图中观察到。本研究的目的是开发一种新型非侵入性方法来测量膀胱壁微运动，并开展初步研究以检验微运动增强与OAB相关的假设。
本前瞻性研究纳入了经ICIQ-OAB调查测量的OAB女性患者和无症状志愿者。使用配备8MHz腹部弯阵探头的GE Voluson E8超声系统，在膀胱充盈至膀胱测压容量的40%后，获取85秒的电影环路图像。使用基于相关性的自定义纹理跟踪MATLAB算法测量膀胱壁厚度随时间的变化，并与膀胱压力变化相关联。根据快速傅里叶变换（FFT）分析，显著的膀胱壁微运动定义为在1.75 - 6次/分钟频率范围内壁厚变化幅度高于0.1mm。该微运动算法在30名女性中进行了测试，其中包括17名OAB患者和13名无症状志愿者。
在41%的OAB患者中识别出微运动，而无症状志愿者中这一比例为0%，表明微运动与OAB存在显著关联（Fisher精确检验，P = 0.010）。还发现微运动与逼尿肌过度活动的临床诊断存在显著关联（Fisher精确检验，P = 0.031）。微运动增强的频率与膀胱压力波动频率相关。
使用经腹解剖运动模式（M型）超声证明了测量膀胱壁微运动的非侵入性方法的可行性。微运动的存在与OAB以及尿动力学确定的节律显著相关。
