静态和动态盆底MRI及扩散张量成像评估女性压力性尿失禁患者尿道形态及功能的应用研究

Evaluation of urethral morphology and function in female patients with stress urinary incontinence by static and dynamic pelvic floor MRI and diffusion tensor imaging

目的探讨静态和动态盆底MRI及扩散张量成像(DTI)评估压力性尿失禁(SUI)患者尿道形态及功能的价值。方法前瞻性收集2020年7月至2021年2月郑州大学第一附属医院经临床诊断的28例女性SUI患者作为SUI组,同期选取年龄匹配的女性健康志愿者45例作为对照组。对所有受试者行静态和动态盆底MRI和DTI。在静态MRI上测量尿道中段内、外括约肌厚度和功能尿道长度(FUL),在动态最大力排相上测量FUL并计算静动态FUL差值,观察静动态MRI上是否存在膀胱颈漏斗征及尿道开放征。对DTI原始图像进行后处理获得尿道括约肌复合体肌纤维束图像,观察图像并测量尿道中段环形括约肌、中央纵行肌肌纤维的各向异性分数(FA)、表观扩散系数(ADC)及3个特征值(λ1,λ2,λ3)。采用独立样本t检验比较SUI组与对照组间静态和动态MRI测量值、DTI参数的差异,采用χ^(2)检验比较2组MRI征象的差异。结果SUI组尿道中段外括约肌厚度、静态及动态FUL均小于对照组(t=-3.95、-5.72、-8.41,P均<0.001);SUI组静动态FUL差值大于对照组(t=4.41,P<0.001);SUI组静动态膀胱颈漏斗征及动态尿道开放征出现率高于对照组(χ^(2)=23.09、22.25、26.59,P均<0.001)。SUI组尿道中段环形括约肌FA值小于对照组(t=-3.48,P=0.001),ADC、λ2、λ3值大于对照组(t=3.19、2.15、2.06,P=0.002、0.038、0.046);2组间尿道中段纵行肌DTI各参数差异均无统计学意义(P均>0.05)。结论静态和动态MRI及DTI能够客观评估SUI患者尿道形态和功能的变化,尿道中段外括约肌厚度变薄,FUL缩短及环形括约肌纤维束微结构被破坏是SUI患者尿道的主要变化。

Objective To explore the value of the static and dynamic pelvic floor MRI and diffusion tensor imaging(DTI)in evaluating the morphology and function of urethra in patients with stress urinary incontinence(SUI).Methods From July 2020 to February 2021,a total of 28 patients with SUI and 45 age-matched healthy controls were prospectively collected at the First Affiliated Hospital of Zhengzhou University.The static and dynamic pelvic floor MRI and DTI were performed for all subjects.The thickness of internal and external sphincter of middle urethra were measured on static MRI images.The functional urethral length(FUL)was measured both on static and maximal strain phase of dynamic MRI images,then the difference of FUL was calculated.The presence of bladder neck funneling and urethra opening were observed on static and dynamic MRI.The muscle fiber bundle image of urethral sphincter complex was obtained by post-processing of DTI original images.The anisotropy fraction(FA),apparent diffusion coefficient(ADC)and three eigenvalues(λ1,λ2,λ3)of annular sphincter and central longitudinal muscle in middle urethra were measured.The independent sample t test and chi-square test were used to analyse the difference of measured parameters in MRI,parameters of DTI and imaging signs between the two groups.Results Compared with healthy controls,the SUI patients showed that the thickness of external sphincter in middle urethral and FUL in static status and maximal strain phase were significantly decreased(t=-3.95,-5.72,-8.41,all P<0.001),the difference of FUL between static status and maximal strain phase was significantly increased(t=4.41,P<0.001).The positive rate of bladder neck funneling in static status and maximal strain phase,urethral opening in maximal strain phase of SUI group increased significantly(χ^(2)=23.09,22.25,26.59,all P<0.001).In SUI group,the FA value of middle urethral annular sphincter decreased significantly(t=-3.48,P=0.001),while the ADC,λ2 andλ3 values increased significantly(t=3.19,2.15,2.06,and P=0.002,0.038,0.046,respectively).There was no significant difference in DTI parameters of middle urethral longitudinal muscle between the two groups(all P>0.05).Conclusions Static and dynamic MRI and DTI techniques can objectively evaluate the changes of urethral morphology and function of SUI patients.The thinning of the external sphincter in the middle urethra,shortening of the FUL and the destruction of the microstructure of the annular sphincter fiber bundle were the main alterations of SUI patients.