Multi-Slice Spiral CT Assisted Morphological Study On Human Pelvic Blood Vessels

ObjectivePelvic cavity is huge and irregular in human body, and the blood vessels distributed in it, just like an inverted tree crown. It seemed all the vessels in this three dimensional space are bending and bringing out offsets endlessly, this result in the systematical morphous of arteries and veins are complicated and changeable, more difficult than those in the limbs, heart and brain. Not only have more difficulties on the morphological study of this arteriovenous system in the cavity, but also have significances should be found out. Most of morphological study methods on pelvic arteries and veins are gross anatomical and section anatomical one, and mainly depend on traditional cadaveric samples, in this way, the findings will be different from those under physiological condition's, we need to carry out the morphological study under physiological condition and find out the regularities in it. With the accelerating scanner speed and enhancive quality of image formation, the multi-slice spiral CT angiography(MSCTA) technique has succeeded in clinical practice in diagnosis on cardiovascular disease, and this bring us the novel method and develop the study on pelvic arteries and veins under the physiological circumstance. We introduced the MSCTA technology into the morphological study on human pelvic blood vessels, based on the investigation of cardiovascular disease, utilizing 16 row 32 slice spiral computed tomography to survey human pelvic arteries and veins under physiological condition, search for the feasibility and specification to fit pelvic angiography and venography. Analyze the shape and the appearance of young people's pelvic blood vessels by using three-dimensional reconstruction method, identify the known arteries and veins, combined with systematic anatomy and imageology, and changed the planar anatomic recognition into three-dimensional one. Arteriosclerosis is the basic character of arteries' pathological change in elderly people; this indicated we should consider the general changes of adult pelvic arteriovenous system in a developing procedure, the arteries gradually changed according to human body's physiological function. Base on the images performed by multi-slice spiral CT, compare the difference between the young people and elderly in pelvic arteries, analysis the variation of elderly pelvic arteries in the appearance and presentation, and find out the general characteristic in them. The pelvic congestion syndrome is a common disease that cursed women, at the aid of MSCT, survey the female pelvic venous system and investigate the anatomic foundation of pelvic congestion syndrome. Scan the cadaveric samples after the pelvic arteries or veins had perfused respectively, reconstruct the vessels and observe the general shape, try to rebuild the graph of arterial and venous system separately.Evaluate the application of MSCTA technique on the morphological study of human pelvic blood vessels, find out the reasonable method to combine the imageology with anatomy together and put into use.Materials and Methods1, General materials: From April to October in 2004, 16 adolescents and 8 elderly people accepted pelvic angiography; all of them are healthy, without coronary artery disease, diabetes mellitus, without pelvic and abdominal cavity disease and surgery history. 8 of the adolescents were young medical members, another 8 were young volunteers in college, were 9 male and 7 female, aged from 19 to 34 years, weight from 51 to 70 kilograms, height 156～175cm. The elderly were people who participate in the regular physical examinations in out-patient clinic, the organizer arranged them undergoing multi-slice spiral CT coronary artery angiography in order to exclude coronary artery pathological changes. Asked for their agreement, we continued the pelvic arteries scanning at the end of heart examination. They were 5 male and 3 female, weight 60～75kg, height 155～170cm. The cadevaric samples were 3 people died for massive blood lost in accident, 1 woman of 32 years for arterial perfusion and 2 men of 35 and 42 years respectively for venous perfusion.2, Administration of contrast medium: All people accepted the iodic sensitivity test, and the results were negative. Established maintenance liquid transfusion for each normal subjects at a median cubital venous venipuncture, transfused the 5% injection glucose liquid, maintained dose was 500ml, prepared adrenaline and dexamethasone for emergency use, in case of supersensitivity happened in iodic injection period. The contrast medium Ultravist 370(Schering Pharmaceutical Ltd, Guangzhou) was injected through median cubital vein at an injection of 3.5ml/s by high pressure syringe. The bodies were perfused for preservation, before the arteries and veins perfused, residual in vessels was washed out by using 1% heparin saline at 37℃. After that, 5% meglucamine diatrizoate and 20% acrylonitrile butadiene styrene resin(ABS) butanone solution was transfused into the abdominal aorta, inferior vena and femoral vein, fill quantity sufficient solidifying agent, red and blue oil into the butanone liquid for arterial and venous perfusion respectively, reperfusion at next day and the day after, until can not fill in. Bodies were immerged in warm water for 6 hours after filled in at each time, when the perfusion finished; they were stored in refrigerator under -30℃for 48 hours.3, Scanning device and technique: Scanning device 16 rows and 32 slice (SOMATOM Sensation 16, Siemens) multi-slice spiral CT applied to the study, manufactured by Siemens in Sep. 2003, put into use in Feb. 2004. Scanning technique Operating voltage was 120 kV; electric current was 54mAs, collimating apparatus 0.75mm, layer thickness 0.75mm, reconstruction layer 0.75mm, pitch 0.75, sweep time of each layer 70ms. The subjects adopted prostration; scanning field was from iliac crest down to a point 3cm under the greater trochanter of femur, scanning direction was from the side of head to the side of feet. Identified and adjusted the scanning boundary by plain scan method, confirmed the abdominal aorta Dot and recorded the whole sweep time. Injected the non-ionic contrast agent(Ultravist 370) and noted time, when computerized tomography number(CTN) of abdominal aorta Dot reached 100Hu, probe executed the arterial period scanning, and noted the time as 0th second, the wholly sweeping time was 10～12s. When the first scan finished, the probe automatic reset, and executed venous period scanning followed the former schedule at the interval of 90 seconds, 130 seconds and 230 seconds respectively, scanned for 4 times. The cadaveric samples scanned for only one time, boundaries same as the subjects.4, Postprocessing: Three dimensional reconstruction performed in Siemens 3D Virtuoso VA31 workstation, cross-section images were reconstructed from iliac crest to the point 3cm under the greater trochanter of femur, the volume rendering technique(VRT) and maximum intensity projection(MIP) were employed, rebuilt the complete pelvic blood vessels graph, analyzed the appearance and the difference of pelvic arteries and veins in different period. Non-parameter measurement tests were used to compare the changes in the quality score of the images, by using Statistical Package for Social Sciences, version 11.5.5, Investigate content: Analyzed the displayed intracavitary arteries and those close to the pelvic cavity, found out the accompanying veins, carried out such study as, 1) Pelvic angiography technique with multi-slice spiral CT; 2) The presentation of young people's pelvic blood vessels after multi-slice spiral CT three dimensional reconstructed; 3) Variability study of pelvic arteries' presentation between adolescents and elderly people with multi-slice spiral CT three dimensional reconstruction; 4) Multi-slice spiral CT assisted anatomic study on pelvic congestion syndrome; 5) Visualized cadaveric pelvic blood vessels with multi-slice spiral CT.ResultsReconstructed young people's 3D images of arterial period displayed well, we can distinguished the 4th lumbar artery, superior rectal artery, common iliac artery, median sacral artery, external iliac artery and the branches of deep iliac circumflex artery, inferior epigastric artery, femoral artery; internal iliac artery and its branches of umbilical artery, inferior vesical artery, superior vesical artery, uterine artery, vaginal artery, obturator artery, iliolumbar artery, superior gluteal artery, inferior gluteal artery and internal pudendal artery. These arteries' appear rate was 100%, the lateral sacral artery's was 75%, and however, the inferior rectal artery didn't display. There were individual differences that the length and diameter of vessels were not same in different people. The arterial fete around the hip joint was abundant in adolescent, principally composed with acetabular branch of superior gluteal artery, inferior gluteal artery and the ascending branch of lateral circumflex femoral artery.Because of the problems in software, the chief veins cannot separated from arteries objectively, need to distinguish at the aid of known arteries; the venous plexus in the pelvic organs appeared clearly. Both arteries and veins were appeared during the 90th second and the 130th second, and the veins showed in a most clear type at 130s in their saturation and contrast(P=0.002). Contrast medium entered in the soft tissue, and gathered in bladder at the 230th second, veins showed with a vague margin but relative independently. The reconstructed VRT 3D images and the MIP figure of young people showed us the complete pelvic arteries, the vessels were smooth and flexible, had plenty of branches, revealed even more than the 4th level vessels, all the branches reached their extremities; but in elderly people, only the 2nd or the 3rd level vessels appeared, the pelvic arteries were inflexible, stiff and had few branches, not smooth as young people, just like a dead tree, only common iliac artery, external iliac artery, inferior epigastric artery, superior gluteal artery, inferior gluteal artery, femoral artery and circumflex femoral artery can be seen. Most of internal iliac artery branches didn't appeared in elderly, however, the arterial rete around the hip joint was ruined, and hardly any 4th level arteries can be seen. In the 2nd level ones, the elderly were significantly constrictive than the younger, at the beginning of common iliac artery and the internal iliac artery, there were calcified plaques exist.In the reconstructed venous VRT 3D images of young woman without childbearing history, we had identified superior rectal anastomotic venous plexus, uterine body venous plexus, parametrial venous plexus, vesicorectal venous plexus; vaginal venous plexus and internal pudendal-parametrial venous anastomose also appeared during the whole period. In the images of young woman who had the childbearing history, the uterine body venous plexus, parametrial venous plexus and vesicorectal venous plexus were not outstanding in the initial stage(90th second), but were in the advanced stage(130th second), there appeared cubic vein communicating between the external iliac veins behind the ramus of pubis.The appearance of the cadaveric pelvic veins was not good as normal one, only presacral venous plexus, femoral vein and its accessory, internal iliae vein and the accessory of superior gluteal veins, inferior gluteal veins and internal pudendal vein appeared. Contrast medium leaked in the major psoas muscle, that deep structure was covered. In the reconstructed pelvic artery VRT images, lots of contrast medium leaked in the muscles, the soft tissue covered the thigh, buttocks and pelvis, interfered the display of pelvic arteries, only the external iliac artery, internal lilac artery, proximate of circumflex femoral artery can be seen at the anterior view, and however, only the internal pudendal artery and part of the inferior gluteal artery appeared, superior gluteal artery was totally covered by intensified images. In the reconstructed pelvic artery MIP images, the VRT color which obscured the blood vessels was removed, the structure of arteries was clear, massive contrast medium was found leaking at some parts of twin superior gluteal artery, inferior gluteal artery and circumflex femoral arteries, without the influence of VRT color, the MIP image revealed exact leakage and the adjacent arteries. Because of dehydration effect, some of the picture element in the sectional images were not correct, thus induced the smoothen degree decreased, caused the integrity of images destroyed, result in the defection of images.ConclusionsMulti-slice spiral CT angiography(MSCTA) technology revealed the detail pelvic blood vessels. The scheduled arterial period scanning should be carried out when computerized tomography number(CTN) of abdominal aorta Dot reached 100Hu, and the venous period scanning should be executed at a interval of 130 second, then dealt the sectional images in workstation, we can obtain the clear 3D reconstructed pelvic arteries and veins images. The morphous of human pelvic arteries are changeable during the growth period, with the aging process, the functional arteries reduced. Young people have the sufficient visible pelvic arteries and their pelvic organs and the tissues might be in good condition; the aged ones have few visible vessels much less than the young people have because their health is in degenerating stage, which implied the function of internal organ also declined, arteriosclerosis was account for the arterial pathological changes, which indicated we need to study the pelvic vessels in some developmental and functional methods. We should concern the pelvic arteries with the human body's physiological functions, and the deterioration of arterial functions could lead to their appearance changing. The pelvic congestion syndrome was relative to the superior rectal anastomotic venous plexus, uterine body venous plexus, parametrial venous plexus, vesicorectal venous plexus, vaginal venous plexus and internal pudendal-parametrial venous anastomose. Diagnosis and treatment rely on these anatomic basics. The cubic vein happened in the woman had bearing history, should be look as a compensation between pelvic veins and external iliac veins during the pregnancy. MSCTA could be a feasible technique of the examinational method for pelvic arteries injuries, and with the upgrade of software, it will distinguish the arteries and veins in pelvic objectively, thus has significant use for pelvic blood vessel disease in future.The noninvasive technique of MSCTA provided the application for morphological study on human pelvic blood vessels, we should introduce the functional anatomy to the morphological study at the aid of this method, develop the anatomic research in a novel discipline, and this will be significantly for analyzing the changes of blood vessels under the functional activity. It is convinced that establish the solid images of pelvic arteries and veins will be helpful for clinical usage, and this method will demonstrate the complexity and differentiation of human pelvic blood vessels better, help the surgeons identify the individual variation, improve the treatment, and reduce the complications.