The Three-dimensional Reconstruction Of Pelvic Organs And Levator Ani Muscle Based On Rest And Dynamic MRI In Normal And POP Women

Pelvic organ prolapse(pelvic organ prolapse,POP)seriously affects the health and quality of life in middle-aged and elderly women.Previous studies have suggested that POP female pelvic organs have different degrees of downward movement,levator ani muscle have various degrees of damage.Clinically by gynecological examination and POP-Q(pelvic organ prolapse quantification,POP-Q)to determine the degree of pelvic organ prolapse,indirectly reflect the damage of pelvic floor support structure,cannot directly observe and objectively reflect the abnormal pelvic support structure,and can not determine whether with enterocele or peritoneal hernia.With the help of imaging evaluation is an important auxiliary method,perineum 3D/4D ultrasound,have certain value for assessing bladder and urethra,but greatly depends on the experience of operator and soft tissue resolution is limited;magnetic resonance imaging(Magnetic resonance imaging,MRI)has high resolution of soft tissue,no radiation,multi-plane imaging,is the study of female pelvic floor excellent imaging method.Static MRI can observe the structure of the pelvic floor,but the evaluation of the degree of prolapse was significantly lower than the clinical diagnosis.Dynamic(valsalva maneuver)MRI,can reflect the maximum degree of prolapse of POP,but the observation of pelvic floor anatomy is relatively poor.Therefore,POP patients should be evaluated by static and dynamic MRI.In the previous study,the maximum degree of POP and the pelvic floor supporting structure were observed only by 2D axial,sagittal and coronal MRI images.However,the maximum degree of pelvic organ prolapse and the maximum angle of levator ani muscle plate,does not surely fall on the same two-dimensional level.The MRI three-dimensional model of static and dynamic pelvic structure based on the static and dynamic MRI raw data are easier to understand the three dimensional anatomical structure of pelvis;and can realize 3D measurement to solve the problems of two-dimensional measurement.Therefore,the purpose of this study is to use static and dynamic MRI original datas to construct,measure and analyse the static and dynamic MRI pelvic structural three-dimensional model in normal fertile and POP female,reflecting the pelvic organs’ movement,Up or down,left or right,front or back before and after Valsalva maneuver in normal fertile and POP female.Part one The comparative study of the static and dynamic MRI three-dimensional model of the pelvic organs and levator ani muscle in normal fertile female[Objective]Exploring dynamic MRI sequences and parameters fitting for reconstructing the dynamic 3D models of female pelvic organs and levator ani muscle,using Mimics 10.01 3D reconstruction software to construct the static and dynamic MRI 3D models of normal fertile female,analyzing the change of position and shape.[Method]First,16 women who underwent pelvic MRI examination in Nanfang Hospital of Southern Medical University were selected,comparing four commonly used dynamic MRI sequences and parameters,chose the most clear,the shortest time as the most suitable dynamic scanning sequence.Then 20 normal fertile females(without pelvic floor dysfunction symptoms)who underwent pelvic MRI examination in Nanfang Hospital of Southern Medical University were selected.They experienced pelvic static T2W TSE and optimal dynamic sequence scan,using Mimics 10.01 to construct the pelvic organs and levator ani muscle static and dynamic MRI three-dimensional model,measuring the projection distance of pelvic organ indicator points to the pubococcygeal line(PCL),pubic spine line(PIS),ischial spine line(IS).The cranial,medial and ventral sides were positive value,the caudal,lateral,and dorsal sides were negative value;and measuring the levator hiatus width and length,Levator symphasis gap left and right side,and levator plate angle.[Results]1.The SSTSE sequence is most suitable for dynamic pelvic organs and levator ani muscle dynamic 3D reconstruction;2.Static MRI can reconstruct the whole pelvis,small composition of levator ani muscle and perineal muscles,but it cannot reflect the position of pelvic organs and levator ani muscle.3.Dynamic MRI(valsalva maneuver)can obtained the position and morphology of pelvic organs and levator ani muscle in normal fertile females when holding the maximum force,but can only reconstruct part pelvis,small muscles displays are poor.4.Static and dynamic combination:dynamic PCL line increases than rest state,PIS and IS have no obvious change;bladder neck,internal cervix,external cervix,anorectal junction respectively moves down 12.63±12.68mm and 9.41 ± 10.46mm,10.51 ± 11.65mm,9.27±6.51mm(P<0.05);bladder neck,internal cervix,anorectal junction left movel-2mm,no clinical significance;bladder neck,internal cervix,,anorectal junction respectively moves back 9.43±8.74mm,9.95±9.07mm,6.92±7.65mm(P<0.05);5.Static and dynamic combination:dynamic than the rest state,levator ani muscle normal "V shape" are reduced,there are more than 5 cases of "U shape";normal "dome shaped"are also reduced,there are more than 4 cases of "groove shaped".6.Static and dynamic combination:dynamic than the rest state,the levator hiatus width and length,Levator symphasis gap left and rightside,levator plate angle respectively increased by 7.44±9.09 mm,4.37±7.49mm,4.60±7.50mm,4.50±7.50mm,3.68±11.28°,the differences were statistically significant(P<0.05),but the degree of change are small.[Conclusion]SSTSE sequence is most suitable for Normal fertile dynamic 3D reconstruction,Normal fertile female dynamic than resting pelvic organ significantly downward and backward move 1cm,the levator ani muscle parameters tend to relaxation,showing normal fertile female’ pelvic floor function has been weakened.Part two The comparative study of the static and dynamic MRI three-dimensional model of the pelvic organs and levator ani muscle in POP female[Objective]Constructing the static and dynamic MRI 3D models of POP patients,analyzing the position and shape.changement of pelvic organs and levator ani muscle.[Method]From October 2014 to April 2017 in Nanfang Hospital of Southern Medical University,according to the POP-Q quantification,26 patients diagnosed with POP were selected.Performing pelvic T2W static FSE and dynamic T2W SSTSE sequence scan(first part explored the optimal dynamic sequence).Using Mimics 10.01 to reconstruct the pelvic organs and levator ani muscle static and dynamic 3D models,measuring the projection distance of pelvic organ indicator points(or prolapse distal)to the pubococcygeal line(PCL),pubic spine line(PIS),ischial spine line(IS).The cranial,medial and ventral sides were positive value,the caudal,lateral,and dorsal sides were negative value;and measuring the levator hiatus width and length,Levator symphasis gap left and right side,and levator plate angle.[Results]1.4 cases of Valsalva maneuver are not good,which are eliminated,the SSTSE sequence is also suitable for POP patients to reconstruct static and dynamic pelvic organs and levator ani muscle 3D models.2.Static MRI can be used to reconstruct the intact pelvis,thin layer to observe whether there is any breakage at the beginning of levator ani muscle,but it can not reflect the maximum degree of prolapse of pelvic organs.3.Dynamic MRI can show the maximum degree of prolapse in patients with POP,and found that 2 cases of patients with small bowel hernia;but the image clarity than resting state is poorer,the levator ani muscle is not as good as the rest observation.4.Static and dynamic combination:dynamic PCL line increases than rest state,PIS and IS have no obvious change.POP patients with bladder neck,internal cervix,external cervix,anorectal junction average down 31.65±23.98mm,28.4±27.53mm,29.10±27.40mm,10.70±13.93mm(P<0.05);bladder neck,internal cervix move right,anorectal junction move left,but mobility is only 1-3mm,no clinical significance;internal cervix,anorectal junction average move back 10.56±12.02mm、7.54±6.4mm(P<0.05),but the bladder forward(bladder prolapse mainly).5.Static and dynamic combination:dynamic than the rest state,levator ani muscle all lost the normal "V shape",and all lost the normal "dome shaped",static than dynamic more detect 8 cases at the beginning of the lower edge of pubic symphysis defect.6.Static and dynamic combination:dynamic than resting levator ani muscle anterior incline and backward movement,the levator hiatus length and width,Levator symphasis gap left and right side,levator plate angle respectively increased by 10.41 ± 12.05mm、8.91±12.28mm、7.02±7.98mm、8.60±7.83mm、14.21±9.97°;,reflecting the levator ani muscle function was abnormal.[Conclusion]Static MRI image is more clear,observing the defect of levator ani muscle in POP patients are better;(Valsalva maneuver)shows maximum prolapse state in patients with POP,and can identify patients with enterocele or peritoneal hernia.Static and dynamic combination is the most beneficial to the comprehensive evaluation of POP patients.Part three The comparison of the static and dynamic MRI three-dimensional model of the pelvic organs and levator ani muscle in normal and POP female[Objective]To compare the differences of static and dynamic MRI 3D models of normal fertile female and POP patients.[Method]Using the first and the second part of the normal fertile female and POP patients’pelvic organs and levator ani muscle static and dynamic MRI three-dimensional models,the three-dimensional measurement results were compared.[Results]1.Age has a significant difference between the normal and POP groups,BMI、Parity(vaginal delivery)were no significant difference between the two groups.2.POP group static and dynamic levator ani abnormal rate was higher than normal group,but the static and dynamic PCL line,PIS line,IS line length were no statistically significant between two groups.3.At static state,bladder neck,internal cervix,external cervix,anorectal junction from the PCL line vertical distance than normal group respectively increase:13.12±2.21mm、16.96±2.28mm、22.85±2.80mm、13.29±2.69mm(P<0.05);bladder neck,internal cervix,external cervix from PIS line level distance and internal cervix from IS line anteroposterior distance have no significant difference between the two groups(P>0.05);but POP than the normal group,bladder neck,anorectal junction to the IS line move backward 4.32±2.13mm,6.94 ±1.90mm(P<0.05).4.Dynamic(Valsalva maneuver),POP group bladder neck,internal cervix,external cervix,anorectal junction’s from the PCL line vertical distance than normal group increase respectively:32.13±6.88mm、35.96±6.41mm、41.43±6.65mm、14.73±3.57mm(P<0.05);anorectal junction from PIS line horizontal distance and bladder neck,internal cervix from IS line anteroposterior distance have no significant difference between the two groups(P>0.05),.but POP bladder neck,internal cervix from rightly move 4.75±1.34mm、6.83±3.04mm,anorectal junction from IS line backward move 7.56±2.63mm than normal group(P<0.05)5.At static state,POP group levator hiatus length,Levator symphasis gap left and right side increased respectively 7.97±2.06mm、6.05±1.79mm、7.37±1.75mm(P<0.05)than normal group,levator hiatus width and levator plate angle were no statistically significant difference between the two groups.6.Dynamic(At valsalva maneuver):levator hiatus length,Levator symphasis gap left and right side,levator plate angle respectively increased by 11.41±3.46mm、6.05±2.77mm、8.55±2.67mm、10.67±2.74mm、7.89±2.950(P<0.05)than normal group(P<0.05).7.Static and dynamic combination:two groups of organ point indication movement contrast,normal fertile group of bladder neck,internal cervix,external cervix,anorectal junction movement degree is 12.63±12.68mm and 9.41±10.46mm,10.51±11.65mm,9.27±6.51mm(P<0.05);POP group of bladder neck,internal cervix,external cervix,anorectal junction movement degree is 31.65±23.98mm,28.4±27.53mm,29.10±27.40mm,10.70±13.93mm(P<0.05);the normal fertile group after the shift of the bladder neck was 9.43 + 8.74mm,POP group with bladder prolapse is bladder forward,two groups of left and right direction and the internal cervix,anorectal junction back move degree had no significant difference.8.Static and dynamic combination:levator hiatus length and width,Levator symphasis gap left and right side,levator plate angle static and dynamic average change is about 2 times than normal group;POP group levator plate angle static and dynamic average change is about 4 times than normal group.[Conclusion]POP underwent static MRI examination can display abnormal compared with normal group,but the dynamic MRI makes differences in the two groups more obvious and more closer to the real clinical state;normal group will force the organs mainly down and back move,move range are about 1cm;POP patients downward movement degree with Valsalva maneuver are clinical correlation,uterus and rectum backward movement were similar to the normal group.But POP group bladder can move forward(bladder prolapse mainly).