Evaluation Of Functional MRI In Women With Pelvic Floor Dysfunction

Part One Observation of 2D and 3D Images of Pelvic Floor in Healthy Young WomenObjective:The diagnosis and treatment of the Pelvic Floor Dysfunction(PFD)needs support of accurate pelvic floor anatomy.Anatomically,there are different views on parts of the pelvic floor structure.Many pelvic floor structures have not been recognized on MRI.The purpose of this study was to observe the anatomical structure and morphology of the pelvic floor using 2D and 3D MRI.Methods:Twenty-five healthy nulligravid young women[(age 22～33years,mean age(25±2)]were enrolled and underwent MRI.1 volunteers were excluded due to image artifacts.The pelvic floor structure of healthy young women was observed by 2D images and 3D reconstruction model based on 2D images.The vertical diameter in the biggest radian of iliococcygeal muscle is a parameter that can reflect the normal shape of iliococcygeal muscle.The left and right vertical diameter in the biggest radian of iliococcygeal muscle measured by two physicians with above 5 years experiences of MRI diagnosis.Differences between two sides were assessed using t-test or Mann-Whitney U test.Results:We described the three layers of pelvic floor support structure,with emphasis on the morphology of the pubocervical fascia,the arcus tendineus levator ani,the arcus tendineus fasciae pelvis and the perineal body on MRI.We reconstructed the 3D model of the pelvic floor support structure and the perineal body.We observed the relationship between the pelvic floor structure and the pelvic organs from the three-dimensional space.There was no significant difference in the vertical diameter in the biggest radian of iliococcygeal muscle on the both sides(P=0.869).The average vertical diameter in the biggest radian of the left iliococcygeal muscle was0.719±0.211.The average vertical diameter in the biggest radian of the right iliococcygeal muscle was 0.729±0.214.Conclusions:The multidirectional imaging of pelvic floor is helpful to identify the pelvic floor structure.The 3D reconstruction model is helpful to observe the spatial distribution of pelvic floor structure.Part Two The Value of Static and Dynamic MRI in Patients with Pelvic Floor DysfunctionObjective:The diagnosis of Pelvic Floor Dysfunction(PFD)mostly depends on symptoms and physical examinations.Pelvic organ prolapse quantitation(POP-Q)is the international standard for the diagnosis of Pelvic Organ Prolapse(POP).However,POP-Q still has limitations.Pelvic floor MRI can evaluate the damage and abnormal of pelvic floor structure and provide support for the diagnosis of PFD.Methods:Fourteen patients with PFD[age 47～77 years,mean age(60.5±2.4)]underwent static and dynamic MRI scans of the pelvic floor.All subjects underwent POP-Q test and urodynamic examinations.PCL(pubococcygeal line,PCL)and HMO system were used to evaluate organ prolapse and pelvic floor changes on midsagittal dynamic image.The levator ani muscle was evaluated by the injury score of levator ani muscle and the vertical diameter in the biggest radian of the iliococcygeal muscle.The evaluation criteria for fascia and arch tendinous were the presence of morphological changes and abnormalities.Kendall’s tau coefficient was used to compare the correlation in POP-Q,PCL grading and injury score of levator ani muscle.Spearman rank correlation analysis and Kendall’s tau coefficient were used to compare the correlation among injury score of levator ani muscle,the vertical diameter in the biggest radian of the iliococcygeal muscle and the evaluation of fascia and arch tendineus abnormity.Results:Twelve patients successfully completed the evaluation of all indicators,and 2 patients could not be evaluated by PCL and HMO system due to poor coordination of Valsalva maneuver.The results suggested POP-Q was not consistent with PCL grading.Bivariate Correlation statistics showed the correlation between them was strong(r:0.717).There was a moderate correlation between POP-Q,the evaluation of fascia and arch tendineus abnormity and the injury score of levator ani muscle(r:0.582).There was a strong correlation between the injury score of levator ani muscle and PCL grading(r:0.917).There was a strong correlation between the injury score of levator ani muscle and the evaluation of fascia and arch tendineus abnormity(r:0.657).There was a moderate negative correlation between PCL grading and the vertical diameter in the biggest radian of the iliococcygeal muscle(r:-0.596).There was no significant statistical difference in the vertical diameter in the biggest radian of the iliococcygeal muscle on both sides,with P value of0.700.The average vertical diameter in the biggest radian of the left iliococcygeal muscle was-0.805±0.797.The average vertical diameter in the biggest radian of the right iliococcygeal muscle was-0.915±0.692.Conclusions:PCL grading is lower than POP-Q in diagnosis of POP.The correlation analysis verified that levator ani injury was the cause of pelvic organ prolapse.A moderate positive correlation between the fascia and arch tendinous abnormity and the injury score of levator ani muscle indicated they may be some connection.Part Three Clinical application exploration of the healthy nulliparous female pubovisceral muscle and perineal body from diffusional kurtosis imagingObjective:Diffusion Kurtosis Imaging(DKI)is a model reflecting the real microstructure water molecules diffusion displacement of non-gaussian distribution compared with Diffusion Weighted Imaging(DWI).The application of the technology mostly concentrated in the central nervous system.This study aims to explore the feasibility of DKI in the pelvic floor and tries to assess the complexity of the pubovisceral muscle and the perineal body.Methods:Asymptomatic nulligravid young females[(age 22～33 years,mean age(25±2)]were recruited and underwent MRI.Single-shot,spin-echo,echo-planar imaging(EPI)for a total of 15 gradient directions and for 3 b values(0,750,1500 s/mm~2).Three radiologists with above 5 years experiences in MRI diagnosis took image processing and data measurements in a double-blinded manner.Kendall’s coefficient of concordance was used to compare the consistency between observers.Two independent sample T-test was used to compare the differences in all measurements of the left and right pubovisceral muscle.Paired sample T test or non-parametric test was used to compare the difference between AK and RK,AD and RD of left and right pubovisceral muscle and perineal body.Results:Twenty-six volunteers successfully completed the scans and measurements of the bilateral pubovisceral muscles and the perineal body for all metrics.There was a good consistency among the three radiologists.The Kendall’s W of all metrics range 0.848 to 0.976.There was no significant statistical difference in all metrics of DKI,with P values of 0.271～0.931.RK was greater than AK in the bilateral pubovisceral muscles(P<0.001).RK was greater than AK in the perineal body(P=0.01).AD were lower than RD in both side of pubovisceral muscles and perineal body(P<0.001).Conclusions:The application of DKI technology in pelvic floor is feasible.This study obtained DT and DK metrics of the pubovisceral muscle and the perineal body in young healthy nulligravid female.Part Four Diffusion Kurtosis Imaging of the Pubovisceral Muscle in Pelvic Floor DysfunctionObjective:The diagnosis of pelvic floor dysfunction(PFD)in traditional MRI mostly based on morphological changes of the pelvic floor structure and pelvic organs,such as local and entire abnormity of the levator ani muscle,the change of position in pelvic organs,enlarged genital hiatus.Traditional MRI can’t detect the abnormal changes of microenvironment inside the pelvic floor structure,especially for the damage before the morphological changes of the pelvic floor structure.The purpose of this study was to explore the structural complexity of the pubovisceral muscle in women with PFD by using DKI.Methods:Single-shot,spin-echo,echo-planar imaging(EPI)DKI was performed in all subjects.Fourteen women with PFD[age 47～77 years,mean age(60.5±2.4)]as the test group.Twenty-six healthy nulligravid young women[(age 22～33 years,mean age(25±2)]as the control group 1,Seven healthy multiparas volunteers[age 46～69 years,median age 51]as control group 2.Three radiologists with above 5 years experiences in MRI diagnosis took image processing and data measurements in a double-blinded manner.Kendall’s coefficient of concordance was used to compare the consistency between observers.Univariate analysis of variance was used to compare the differences in each metric among the observers.Differences among groups were assessed using t-test or Mann-Whitney U test.Results:The three groups successfully completed measurements of the bilateral pubovisceral muscles for all metrics.There was a good consistency among the three radiologists.The Kendall’s W of all metrics range 0.834 to0.994.There was no significant statistical difference in all metrics of DKI,with P values of 0.155～0.978.There was no significant statistical difference in all metrics of the left and right pubovisceral muscles among three groups,with P values of 0.224～0.957.The DK metrics(MK,AK,RK)of the left and right pubovisceral muscles were significantly different between the test group and the control group 1(P<0.001).Bilateral AK,RK and left MK values were significantly different between test group and control group 2(P<0.05);There were significant differences in bilateral RK values between control group 1and control group 2(P<0.05).Conclusions:DKI can detect the differences of microstructure between patients with PFD and health people.DKI is highly sensitive to changes in the internal structure at an early stage when there is no obvious change in morphology and signal in MRI.