【作者】 徐国萍；

【导师】 韩悦； 白玫；

【作者基本信息】 天津医科大学 ， 影像医学与核医学， 2010， 硕士

【摘要】 目的：压力性尿失禁(SUI)属于盆底功能障碍性疾病(PFD),绝大多数见于女性。关于SUI的发病机制有诸多理论,主要包括压力传导理论、“吊床”假说、盆底整体理论等,这些理论均认为SUI发生直接或间接地与尿道周围支持结构薄弱有关。尿道支持韧带及肛提肌共同作用以维持控尿,同时尿道的活动度与尿道支持韧带及肛提肌密切相关,而目前对于尿道支持韧带组成仍然存在争议。MRI具有多方位、高软组织分辨率的成像优势,可直接显示尿道支持结构,从而利于评价尿道支持韧带的形态学改变。利用MRI技术观察正常的尿道支持韧带的组成、形态及走行,进而与SUI患者的尿道支持韧带的形态学变化进行对照研究；同时采用动态MRI成像技术观察、比较正常健康女性和SUI患者的肛提肌的功能状态及尿道活动度的变化,以评价MRI在SUI诊断中的作用。另外,通过对进行经闭孔尿道吊带术(TOT)治疗的SUI患者术前及术后1周的MRI检查结果的对比分析,以明确MRI对SUI患者术后尿道支持韧带及尿道活动度改变的评价作用,即MRI对手术短期疗效的评价作用。材料与方法：本研究利用MRI检查技术,对28例健康女性志愿者和16例SUI患者(其中7例伴有盆腔脏器脱垂)行静息及屏气用力状态下的盆腔MRI研究,采用常规轴位、矢状位、冠状位扫描。静息状态下的MRI用于观察正常健康女性及SUI患者尿道支持韧带的形态学表现；屏气用力状态下的MRI用于观察用力前后肛提肌及尿道活动度变化情况；同时测量二种状态下H线、M线、盆膈裂孔横径、尿道长度、尿道倾斜角、尿道膀胱后角、耻骨后间隙、膀胱尿道连接部至耻尾线距离及提肌板角,并对测量结果组间进行统计学分析。研究中测量数据距离单位为毫米(mm),角度单位为度(°),数据满足正态性分布,用均数±标准差进行描述；组间用配对t检验和两组独立样本t检验进行比较；非正态性资料用中位数M、第25百分位数P25和第75百分位数P75进行统计描述；组间比较用两组独立样本秩和检验。所有假设检验的检验水准为a=0.05。结果：1、正常人静息状态下尿道支持结构MRI表现尿道的四组支持韧带包括尿道周围韧带、尿道旁韧带、耻骨尿道韧带和尿道下韧带,其在T1WI和T2WI上均表现为偏低信号,以T2WI更为显著,形态总体呈细条状,边缘锐利,围绕尿道分别呈“弧形”及“斜线”样走行。尿道周围韧带两端起自耻骨直肠肌的内侧面,经尿道的腹侧走行；尿道旁韧带为一对连接尿道侧壁和尿道周围韧带的斜线样结构：耻骨尿道韧带由尿道腹侧发出止于耻骨后方,呈悬带样；尿道下韧带为尿道背侧吊带样结构,向前侧方延伸与盆侧壁盆筋膜腱弓相连。尿道的支持韧带是固定尿道,防止尿失禁的重要结构。肛提肌主要由耻骨直肠肌、耻骨尾骨肌及髂骨尾骨肌构成,在T2WI像上均呈中等信号,包绕在尿道、阴道及直肠两侧,横断面白上由至下分别呈“扇形”、“V”、“U”形,三对肌肉之间没有明确分界。肛提肌能主动收缩对抗腹压增高,参与维持脏器的正常功能及位置。2、正常人屏气用力状态下尿道支持结构的MRI改变屏气用力状态下的MRI显示正常健康女性用力前后尿道支持韧带及肛提肌各组成部分形态无明显变化,盆膈裂孔横径平均增大2mm H线、M线用力后可有轻度增大分别为52.7mm、11.0mm(用力后H线<6cm、M线<2cm),提肌板用力前后与耻尾线基本平行,尿道倾斜角、尿道膀胱后角用力后轻度增大,分别为7.0°、4.0°,尿道长度平均缩短2.00mm。3、SUI患者尿道支持结构的静态及屏气用力状态下的MRI改变静息状态下SUI患者尿道的四组支持韧带有不同程度的形态学改变,总体上表现为韧带的松弛或断裂,其中尿道周围韧带常呈“波浪状”改变；尿道旁韧带表现为短缩；耻骨尿道韧带表现为与耻骨后盆筋膜腱弓分离；尿道下韧带表现为与盆侧壁的盆筋膜腱弓分离；屏气用力状态下上述改变仍存在,无显著性变化。SUI患者的肛提肌在静息状态下其形态学表现与正常人相近,但在屏气用力状态下肛提肌的形态变化比较明显,表现为耻骨直肠肌及耻骨尾骨肌向外后方膨隆,致使盆膈裂孔呈“O”形增大,髂骨尾骨肌呈“盘状”加深,伴有盆腔脏器脱垂(POP)者上述表现更为显著。屏气用力状态下H线>6cm、M线>2cm,提肌板向尾侧倾斜平均20°；尿道倾斜角增大,甚至呈水平位；尿道膀胱后角增大、消失；尿道长度平均缩短4.80mmm。4、SUI患者术前与TOT术后1周MRI检查结果比较静态及屏气用力状态下MRI上尿道的四组支持韧带及肛提肌形态未见改变；通过测量显示尿道的活动度较术前略有减小,经统计学分析后表明其差异无统计学意义。结论：1、MRI可以较好的显示尿道的四组支持韧带及肛提肌形态学特征,并可客观评价肛提肌的功能性状态及尿道活动度,从而对SUI患者术前诊断提供影像学依据。2、MRI可以反映TOT手术后的SUI患者尿道周围支持结构及尿道活动度的变化情况,对手术近期疗效的评价有一定作用,若增加病例数及延长随访观察时间,有望对手术治疗效果作出客观影像学评价。更多还原

【Abstract】 Objective:Stress urinary incontinence (SUI) is due to pelvic floor disfunction, most found in women. On the pathogenesis of SUI have many theories, including the pressure transmission theory, "hammock" hypothesis,and the integral theory. These theories consider that SUI occurs because of the urethra supporting structure defects. Urethral support ligaments and the ani levator muscles control urine, urethral mobility connects with urethral support ligaments and the levator ani muscles. The composition of the urethral support ligaments is still controversial. MRI can show the urethral support structures well. Using dynamic MRI we observe the composition, morphology and courses of the urethral support ligaments and ani levator muscles, and then compare with the patients with SUI. In addition, the SUI patients who accepeted TOT treatment before and. after operation 1 week had given MRI examination to understand the value of MRI in evaluating postoperative effect. Materials and Methods:28 healthy volunteers and 16 SUI patients in which 7 cases with POP accepted static and dynamic pelvic MRI examination. Static MRI observes urethral ligaments, dynamic MRI observes urethral activity and morphological changes of levator ani muscle, and under two states measure H line, M line, diameter of pelvic diaphragm, urethral length, urethral tilt angle, posterior urethrovesical angle, retropubic space, the distance from urethrovesical junction to the PCL and levator plate angle. The measurement results of groups were statistically analyzed. The datas according with normality using mean±standard deviation descriptions, between two groups using paired t test and two independent sample t test. Non-normal data using the M, P25 and P75 for the statistical description, between two groups using two independent sample rank sum test. All hypothesis testing standards were a= 0.05.Results:1. Normal static MRI performance of urethral support structures The urethral support ligaments in T2WI are slightly low signal. Periurethral ligament originating from the inner side of puborectalis, running close to the ventral urethra; paraurethral ligament connecting the lateral wall of urethra to the periurethral ligament; pubourethral ligament originating from the ventral urethra to the posterior aspect of the pubic bone, was suspended with sample; suburethral ligament lying dorsal urethra hammock-like structure, connecting the urethra and pelvic arcus tendinous fasciae. The urethral support ligaments fix urethra and prevent SUI. Ani levator muscles compose of puborectalis, pubococcygeus and iliococcygeal muscle, in T2WI muscles showed a moderate signal. Levator ani muscle contraction can resist the increased abdominal pressure and maintain normal organ function and location.2. Normal dynamic MRI changes of urethral support structures Healthy women ani levator muscles had no significant morphological changes, diameter of pelvic diaphragm, the H line, M line, posterior urethrovesical angle, retropubic space and the distance from bladder neck to the PCL increased slightly after force, urethral tilt angle, after force increase lightly. Levator plate always parallel to PCL.3. Urethral support structures in static and dynamic MRI in patients with SUI SUI patients urethral support ligament changes, including laxity or rupture.Morphological changes of the levator ani is obviously, diameter of pelvic diaphragm increases, diaphragmatic hiatus was "O" shape in SUI with POP. H line> 6cm, M line> 2cm, levator plate caudal tilt average 20°. In SUI patients after force urethral length shorten, most or all of the urethra below the inferior edge of symphysis pubis; urethral inclination angle and posterior urethrovesical angle increase.4. SUI patients before and after TOT 1 week MRI imaging examination results The modality of urethra support ligaments did not change, postoperative urethral activity improved, but the difference was not statistically significant. Conclusion: 1. MRI can better show the morphology of four urethral support ligaments and levator ani muscles,and can objectively evaluate the functionality status of the levator ani and urethral activity degree, and thus supply imaging evidence for preoperative diagnosis of SUI.2. MRI can reflect the changes of urethral support structure and urethral activity of post-operative patients with SUI. MRI has a role in evaluation of curative effect of surgery. By increasing the number of cases and extending follow-up observation period, MRI is expected to give an objective image evaluation in surgical effect.更多还原