Local Imaging Features Of Perirectal Fascia And Its Clinical Significance

Objective: The anatomical structure and imaging characteristics of rectum and perirectal structures were studied by using MRI imaging technology.By adopting different cross-sectional scanning sequences,the local morphology and course distribution of rectum and perirectal structures were thoroughly understood,and the display rate of rectum and perirectal structures was analyzed,so as to provide more objective imaging basis for the surgical treatment of local surgical diseases.Methods: From June 2018 to September 2018,70 healthy volunteers who came to The First Affitiated Hospital of Hebei North University for physical examination were selected by random sampling.Among them,37 were males and 33 were females.Their age distribution ranged from 22 to 60 years with an average age of 43.5 + 20.8 years.There were no abnormal changes in the appearance of the spine,no displacement and fracture of the spine,and no definite intestine in the past medical history.Pathological changes of the canal system.The Discovery TM MR750 series 3.0 TMRI produced by GE Company was used in this study to perform routine cross-sectional serial scanning of the rectum and surrounding fascia in 70 patients,including sagittal T2WI,T1WI,T2WI,and T2 W SPAIR.After scanning according to the above sequence,the generated image is transmitted to AW Volume Share 4 AW4.5 workstation,and the inspection results are processed by an MRI image processing system.Then,the image obtained from the above sequence is used as the location image for the next inspection,and then the transverse,coronal and sagittal scans of the small FOV T2WI sequence are carried out.After MRI scanning,two imaging professionals above the technical level read the films independently,and evaluated the image quality of all sequences.Through comprehensive analysis of MR images of different sequences of rectum and its surrounding structures in 70 subjects,the display rate and score of rectum and its structure in each case were recorded.SPSS20.0 statistical software was used for statistical analysis of data.In order to reduce the occurrence of errors and improve the accuracy of the study,the data collected from each part of each subject were measured three times,and finally the average value was calculated.Statistical methods of t test and analysis of variance were used to set P < 0.05 with statistical significance.Results:1.There are significant differences in the image quality of rectum and its surrounding tissues on different sequence levels(P<0.05).The clearest image sequence is small FOV coronal and cross-sectional,which can clearly show the anatomical structure of rectum and its surrounding tissues.2.In MR imaging,the rectal wall can be displayed in 1-3 layers.Among them,23 cases(32.86%)could not be stratified in T1 WI sequence,7 cases(10.00%)could not be stratified in T2WI sequence,36 cases(51.43%)could not be stratified in T2 WSPAIR sequence and 6 cases(8.57%)could not be stratified in small FOVT2WI sequence.Statistical analysis showed that small FOVT 2WI sequence had the clearest layered development of rectal wall,which had significant difference with other sequences(X2=10.367,P=0.003).3.In the area of perirectal fascia,the intrarectal structures of 70 subjects can be displayed in the MRI images through the observation of T2 W SPAIR sequence.However,the above five kinds of mesorectal fascia,such as peritoneal reflex,rectal fascia,mesorectal fascia,presacral fascia and Denonvilliers fascia,could not be displayed on the MRI images of T2 W SPAIR sequence.The mesorectal and mesorectal structures can be displayed on MR images on three different routine sequences of small FOV,T2WI,T1WI and T2WI.4.The percentages of normal T1 WI in anterior fascia,posterior fascia,left fascia,right fascia,Denonvilliers fascia,presacral fascia and peritoneal reflex were 56(80.00%),27(38.57),55(78.57%),56(80.00%),55(78.57%),56(80.00%),28(41.43%)and 30(42.86%)respectively.The percentages of normal T2WI in anterior fascia,posterior fascia,left fascia,right fascia,Denonvilliers fascia,presacral fascia and peritoneal reflex were 56(80.00%),28(40.00%),55(78.57%),56(80.00%),56(80.00%),55(78.57%),29(41.28%)and 28(40.00%)respectively.The number of small FOV T2WI sequences in anterior fascia,posterior fascia,left fascia,right fascia,Denonvilliers fascia,presacral fascia and peritoneal reflex was 68(97.14%),70(100.00*),67(95.71%),69(98.57%),66(94.29%),64(91.43%),65(92.86%)61(87.14%).Statistical analysis showed that there was no significant difference between conventional T1 WI sequence and conventional T2WI sequence in the display ratio of MR images in rectum and its surrounding tissues(X2=1.276,P=0.105),while the display ratio of small FOV T2WI sequence in rectum and its surrounding tissues was significantly higher than that of conventional T1 WI sequence and conventional T2WI sequence(X2=13.657,P=0.000).5.The structures of lateral ligaments around rectum and pelvic plexus can not be displayed in conventional T1 WI,T2WI or T2 W SPAIR sequences.On the small FOV T2WI sequence,although the lateral ligaments could not be displayed,the pelvic plexus could be partially displayed.The left pelvic plexus was 57(81.43%)and the right pelvic plexus was 59(84.29%).There was no significant difference between the left and right pelvic plexus(X2=2.017,P=0.084).6.The scores of small FOV T2WI sequence were significantly higher than those of T1 WI sequence,T2WI sequence and T2 WSPAIR sequence(P < 0.05).However,there was no significant difference in the imaging scores of the peripheral rectal ligaments and pelvic plexus between the T2 WSPAIR,T1WI and T2WI sequences(P > 0.05).Conclusion:1.NMR can accurately measure and locate the structure of rectum and its surrounding tissues.It is an important method to study the structure of rectum and its surrounding tissues in vivo.2.Small FOV T2WI sequence can clearly display the MRI images of rectum and its surrounding tissues.The anatomical location of rectum and its surrounding tissues can be clearly determined by magnetic resonance imaging technology.The vivo images and data of human body can be obtained effectively under non-invasive conditions.