The Experimental Study On Correlation Of Left Renal Homodynamic Change And Imaging Findings In Nutcracker Syndrome

Object: To establish rabbit model of the nutcracker syndrome (NCS) suitable for imaging with evaluation by multi-slice CT angiography (MSCTA)Material and method: 20 rabbits were randomized into group A(ligation of 50%) and group B(ligation of 75%) with 10 each, 20 rabbits before ligated were as group C(control group).Before extra-luminal ligation on left renal vein (LRV), MSCTA was applied to measure the cross section area of LRV (CSALVR) closest to included angle between abdominal aorta and superior mesenteric artery. Establishment of NCS rabbit model was used extra-luminal ligation on LRV. Rabbits were laparotomized under anesthesia, and LRV was ligated with touch needle compressed externally in varied diameters based on CSALVR×(1-ligation percentage). Then touch needle was removed while LRV was still ligated as estimated using suture silk, and MSCTA was applied afterwards 24 hours to measure the actual post-ligation CSALVR using MPR, CPR and VRT. Analyze the differences between actual and hypothetical post-ligation CSALVR based on CSALVR×(1-ligation percentage) using t-test and between the CSA of proximal and distal LRV segments around the ligation as well.Results: No significant difference was revealed between actual and hypothetical post-ligation CSALVR (P>0.05) for A,B groups, while significant difference was indicated between the CSA of proximal and distal LRV segments around the ligation for A,B groups compared C group(P<0.05),the same between A,B groups as well(P<0.05).Conclusion: (1)Establishment of NCS rabbit model using extra-luminal ligation on LRV in different percentages is easy-performing and effective for imaging study.(2)Establishment of NCS rabbit model simulating different compressions shows further potentials for the study of consequent homodynamic change of left kidney and related pathologic change as well. Objective: To explore the correlations among various left renal homodynamic change and related pathologic change of NCS rabbit model simulating different compressions with MSCTP combined LRV-IVC pressure and pathologic change.To provid theoretical basis for clinical treatment planning and prognosis appraisal.Material and methods: (1)MSCTP examination:expeimental animals and model establishment were same with Part one. 30 rabbits were randomized into group A(ligation of 50%) ,group B(ligation of 75%) and group C(control group)with 10 each. Three groups were all MSCTP examinated.To estimate LRV ligation accuration with MSCTA for groupA,B after ligated 24 hours(Part one),and were undertaked MSCTP examination after liagated 5-6 days for successful models. (1)MSCTP were applied afterwards to measure the BF, BV, MTT and PT in left renal cortex at the level of renal hilus using syngo Body PCT (Siemens, Germany), and the relative time-density curves (TDC) and perfusion maps were studied as well. The parameters were as follows: contrast volume 2ml/kg,flow rate 1ml/s and scanned for 50s at 0.5s interval.(2) the LRV-IVC pressure difference was measured using the left distal renal vein segment after ligation, and the differences among group A,B and C were evaluated using independent t-test.(3)The general shapes and pathobiology observation of left kindney: to observe colour and size of bilateral kidneys after experiment termination. pathological changes of left kidneys were investigated via HE staining, and comparisons with the control group were carried.Results1 Left renal cortex TDC featuresLeft renal cortex TDC in control group: the baseline segment was longer than that in aortic TDC; the rising segment was comaparatively steep, but gradient lower than that of the aorta; when the cure reached its peak, the declining segment first declined fast and slightly, and the it turned into plateau period, maintaining its steadly declining.Left renal cortex TDC in ligation group: the start point of ascending was postoned; the ascending segment of TDC of ligated groups tended to be flat with decreased speed and peak value, peak time lated and peak value lowed, descending segment after peak also indicated decreased speed and tendency to be flat. The above tendencies appeared more significantly in group B than A.2 Left renal cortex CT perfusion paramaters and LRV-IVC pressure: in terms of BF, MTT and PT, significant differences were revealed between group A and B, and group A, B and control as well(P<0.05).No significance was showed on BV between group A and control (P>0.05), while the opposite occurred between group B and control (P<0.05). In terms of LRV-IVC pressure difference, significances were revealed between group A, B and C (P<0.05), and between group A and B as well (P<0.05).(3)Left kidneys appeared enlarged and reddish in group A ,while enlargement and congestion with tensed encapsulation were showed in group B. Verifications of pathology showed glomerulus interstitial capillary dilation and mild congestion in group A, while severe congestion was revealed in group B, with dilation of medullary vessels and glomerulus structure collapsed.Conclusions:(1)as a non-invasive evaluation method, MSCTP accurately revealed homodynamic changes of left kidney in NCS.(2)with compression of 50% in the rabbit NCS model, decreased BF and prolonged MTT were indicated , LRV-IVC pressure differences was up to 5-6cmH2O,left renal mild congestion was showed. Even more significant changes showed with the increased compression to 75%.Clinical Significance/Relevance: Multi-slice CT perfusion on left kidney in NCS rabbit animal model provide further potentials of studying consequent pathological and homodynamic changes of left kidney and promises in clinical treatment planning as well.