Study Of Tomographic Ultrasound Imaging,Magnetic Resonance Imaging Of Normal And Injury Female Levator Ani Muscle

ObjectiveTo identify the anatomical structures of nulliparous female levator ani muscle by tomographic ultrasound imaging and magnetic resonance imaging.The spatial stereoscopic parameters of the levator ani muscle were measured on the three-dimensional reconstruction model.Methods1.To follow up postpartum women after vaginal delivery in our hospital during December 2015 to October 2016 by perineal three-dimensional ultrasound.To screen out 20 women with levator ani muscle injuries.20 nulliparous women with normal pelvic support were recruited in this study as normal control group.2.Three-dimensional ultrasonography was used to obtain the three-dimensional ultrasonography of the levator ani muscle.Then enable TUI imaging technique to obtain multi-plane ultrasound patterns of levator ani muscle.To identify the composition and walking of the levator ani muscle.LUGs were measured on the slice0,1,2.3.Magnetic resonance imaging scans of levator ani muscle were obtained in thin slices.To identify the composition and walking of the levator ani muscle on the cross section,sagittal,coronal plane.4.The three-dimensional geometric model of the levator ani muscle was reconstructed by medical image reconstruction software Mimics.To study the composition and walking of levator ani muscle in the space and LSG,ICA,ICW,ICHA,ICOIA were measured on three-dimensional models.Results1.Normal female levator ani muscle performance:TUI performanceCross section image: TUI can clearly show the puborectalis,puboperineal,puboanal and part of the shape of iliococcygeus muscle.The puboanal muscle is attached to the anal canal.The puboanal muscle is attached to the anal canal.The puboperineal muscle is attached to the perineum.The origin of the medial margin of the pubic bone of the pubis muscle is closer to the lateral than the pubic muscle,and then bypass the posterior side of the rectum connected to the other side of the pubic branch medial margin,as a sling.Coronal image: Pubovisceral muscle and puborectalis muscle fibers are perpendicular to the scanning plane.They travel together on both sides of the vagina without obvious demarcation.Similarly,the composition of the pubic visceral muscle is also difficult to distinguish on the coronal plane.Sagittal image: The sagittal plane can show the muscles from the medial margin of the pubic branch,but it is difficult to distinguish the muscle fibers of the pubovisceral muscle and puborectalis.MRI performanceCross section image: MRI can clearly show the puborectalis,puboperineal,puboanal and iliococcygeus muscle.Puborectalis,puboperineal,puboanal observed in the MRI cross-section similar to the TUI.Iliococcygeus muscle can be displayed on the MRI.The iliococcygeus originates from the anusual tendon arch covering the muscle surface of the obturator.Coronal image: Pubovisceral muscle and puborectalis muscle fibers are perpendicular to the scanning plane.It is difficult to distinguish the startings and ending points of puborectalis,puboperineal,puboanal muscle on the coronal plane.They travel together on both sides of the vagina without obvious demarcation.Similarly,the composition of the pubic visceral muscle is also difficult to distinguish on the coronal plane.The coronal plane images can be used to observe the iliococcygeus muscle near the dorsal side.It originates from the side of the levator tendon arch and ends in the coccyx,like wing structure.Sagittal image: The biggest advantage of the sagittal plane is that the scanning plane is parallel to the pubovisceral muscle and puborectalis muscle fibers.It can be used to observe the direction of muscle fiber walking.It can clearly show the puboperineal to the head side of the line connected to the perineum.It originate from the medial margin of the pubic branch to the upper side of the anal sphincter walking.But the pubovaginal muscle in this section can not be identified.The fibers of the puborectal muscles are visible because they form "bulge" through the back rectal fibers.The sagittal plane can show the iliococcygeus muscle walking,from the obturator muscle surface of the anusual tendon connected to the dorsal side of the coccyx.Three-dimensional model: The dimensional structures and spatial position relationship of Pelvic bony structures(Pelvis,Coccyx),Pelvic organs(urethra and bladder,vagina and cervix,anal canal and rectum),levator ani muscle(puborectalis,puboperineal,puboanal and iliococcygeus)can be showed.It can also display cross-section,coronal plane,sagittal plane provided on the anatomical information.2.Postpartum women with levator injuries performance:TUI performancePuborectalis,puboperineal avulsion manifested as muscle and pubic branch connection site muscle fiber echo continuous interruption.Iliococcygeus muscle injury can not be shown on TUI.MRI performancePuborectalis,puboperineal avulsion showed muscle and pubic branch of the connection site muscle fiber signal interruption.On MRIs the morphological changes of iliococcygeus could be well-observed,inculding becoming thin but still be attachedto ATLA(n=6),or breaking in the middle part without avulsion(n=2),detaching from the ATLA with obturator muscle injury(n=2)or without obturator muscle injury(n=3).But we recommend if a patient is found with severe injury of the puborectalis,it is necessary to perform a MRI examination to rule out iliococcygeus muscle injuries.3.Comparison of normal and injury female levator ani muscleComparison of ICA: The expression of ICA-L(17.45±3.5°)in the levator ani muscle injury group was higher than that in the normal group(12.28±3.19°),the ICA-R(16.44±4.23°)in the levator ani muscle injury group was higher than that in the normal group(11.54± 3.41°),The difference was statistically significant.Comparison of ICW: The expression of ICW-L(47.22±4.35mm)in the levator ani muscle injury group was smaller than that in the normal group(51.97±3.04mm),the ICA-R(49.47±3.54mm)in the levator ani muscle injury group was smaller than that in the normal group(53.59 ± 3.54mm),The difference was statistically significant.Comparison of ICHA: The expression of ICHA-L(50.74±11.36°)in the levator ani muscle injury group was higher than that in the normal group(40.04±9.86°),the ICHA-R(45.25±9.79°)in the levator ani muscle injury group was higher than that in the normal group(39.74±8.81°),The difference was statistically significant.Comparison of ICOIA: The expression of ICOIA-L(96.97±26.44°)in the levator ani muscle injury group was higher than that in the normal group(71.77±7.03°),the ICOIA-R(95.12±24.96°)in the levator ani muscle injury group was higher than that in the normal group(71.13±5.97°),The difference was statistically significant.Comparison of LSG: The LSG of levator avulsion(37.39±4.11mm)was greater than that of intact levator ani muscle(21.81±2.96mm)(P<0.05).Comparison of LUG: The LUG of levator avulsion(27.94±2.53mm)was greater than that of intact levator ani muscle(19.78±1.35mm)(P<0.05).Conclusion1.TUI and MRI cross-section can identify the various components of the levator ani muscle,starting and ending point.MRI coronal and sagittal plane can also provide anatomical morphology of part of the levator ani muscle.But the cross-section in the identification of levator ani muscle is most effective.2.MRI combined with three-dimensional reconstruction in the spatial perspective to show the three-dimensional configuration of the levator ani muscle,which provides an important imaging basis for clinical pelvic floor reconstruction.3.TUI and MRI can be used for the diagnosis of puborectalis,puboanal muscle avulsion,and MRI can be used to diagnose iliococcygeus injury.4.TUI and MRI are effective examinations to dignose levator avulsion.LUG and LSG are good imaging parameters to evaluate the levator avulsion in postpartum women.5.Levator ani muscle injury lead to ICA,ICOIA increased and ICW decreased.6.ICA,ICOIA,ICW changes in the postpartum levator ani muscle injuries,iliococcygeus muscle's configuration also changes.