Lee Su-Lin, Tan Emile, Khullar Vik, Gedroyc Wladyslaw, Darzi Ara, Yang Guang-Zhong
Royal Society/Wolfson Foundation Medical Image Computing Laboratory, Department of Computing, Imperial College London, London SW7 2AZ, UK.
IEEE Trans Med Imaging. 2009 Jun;28(6):926-36. doi: 10.1109/TMI.2009.2012894. Epub 2009 Jan 19.
The levator ani is the main muscular support of the pelvic floor organs and damage caused by childbirth can affect its function. The full functionality of this muscle group is still unknown but it is essential for effective surgical planning. To elucidate its functional significance, a physical-based statistical shape model was built from the levator ani surfaces of 15 subjects scanned in an open access scanner. Simulation of dynamic exercises was performed on the resulting surfaces with finite element analysis. Statistical shape modeling was performed on the training set consisting of the original and simulated shapes along with thickness and strain distributions. Simulation results are presented on 15 subjects. The statistical shape model shows good correspondence to inter- and intra-subject shape variability, with the modes of variation highlighting movement in the posterior of the levator ani as well as in the levator arms. Strain distribution plots and the modes of variation show results that correspond to clinical findings. Further validation of the technique and a repeatability test were performed on four subjects with internal global pressure readings taken from a perineometer and five patients suffering from minor pelvic floor disorders due to obstructed defaecation. A Mann-Whitney nonparametric test was used to compare the normal model fitting to the two subject groups.
肛提肌是盆底器官的主要肌肉支撑，分娩造成的损伤会影响其功能。该肌群的全部功能仍不明确，但对于有效的手术规划至关重要。为阐明其功能意义，利用在开放式扫描仪中扫描的15名受试者的肛提肌表面构建了基于物理的统计形状模型。使用有限元分析对所得表面进行动态运动模拟。对由原始形状、模拟形状以及厚度和应变分布组成的训练集进行统计形状建模。在15名受试者上展示了模拟结果。统计形状模型与受试者间和受试者内的形状变异性具有良好的对应关系，变异模式突出了肛提肌后部以及提肌臂的运动。应变分布图和变异模式显示的结果与临床发现相符。对4名通过会阴压力计获取内部整体压力读数的受试者以及5名因排便梗阻患有轻度盆底疾病的患者进行了该技术的进一步验证和重复性测试。使用曼-惠特尼非参数检验比较正常模型与两个受试者组的拟合情况。
