Regional perfusion,oxygen metabolism,blood volume and immunoglobulin G accumulation at focal sites of infection in rabbits

Infection causes remarkable changes in extracellular fluid volume, blood flow and oxygen consumption in the region of the lesion. To determine the sequence and magnitude of these changes, we performed serial scintigraphic measurements in 10 rabbits with experimental Escherichia coli abscesses. Positron emission tomography with C¹⁵O₂, ¹⁵O₂ and ¹¹CO was used to measure regional blood flow, oxygen extraction (OEF) and blood volume; extracellular fluid volume was evaluated by single photon scintigraphy with indium-111 immunoglobulin G (IgG). Images were recorded following tracer administration at 1 and 7–10 days after infection. At the first imaging time, blood flow to infected muscle had increased by 40% compared with control sites (7.4±0.6 to 10.8 ± 3.8 ml/min · 100 g), OEF had decreased from 55%±34% to 45%±14%, and the infected-tocontralateral (I/C) ratio of IgG had increased to 3.34±1.85. At the later imaging time, flow had increased by almost threefold compared with day 1 (29.4±9.8 ml/min · 100 g), OEF had decreased to 29%±14%, and the I/C ratio for IgG had remained constant. Although OEF fell,oxygendelivery (OEF × flow) increased from 4.07 ml/min (control value) to 4.86 ml/min on day 1 and 8.64 ml/min on days 7–9. The infected-to-contralateral (IC) ratio of ¹⁵02/C¹⁵O₂ was 0.74±0.15 on day 1 and 0.77±0.10 at 7–9 days. These studies indicate that expansion of the extracellular fluid volume increases early in the evolution of the infection and exceeds changes in regional perfusion and oxygen delivery.     

Accumulation of immunoglobulin G at focal sites of inflammation.

To evaluate the factors responsible for the accumulation of indium-111 immunoglobulin G (111In-IgG) at sites of inflammation, sequential measurements of tissue blood volume, interstitial fluid volume and accumulation of radiolabelled albumin and IgG were made in rats following Escherichia coli infection in the thigh. Compared with normal thigh muscle, there was approximately two-fold increase in interstitial fluid volume and approximately 1.5-fold increase in plasma and red blood cell volumes in infected muscle. For both proteins, there was a fivefold increase in influx rate constant (kin) in infected muscle. In normal muscle, the interstitial fluid concentration of labelled human serum albumin (111In-HSA) was significantly higher than that of 111In-IgG (P less than 0.01). In contrast, the concentrations in infected muscle were nearly identical. The concentration ratios (infected to normal muscle) were 1.7:1 for HSA and 3:1 for IgG. These data suggest that the infection imaging properties of 111In-IgG are related to expansion of the space available to macromolecules in infected tissue and increased transport into this space. At clinically important imaging times (24-48 h after injection), the higher target-to-background ratio of 111In-IgG compared with 111In-HSA is not due to the higher accumulation IgG in infected tissue but rather to the higher accumulation of HSA in normal tissue.     

Accumulation of immunoglobulin G at focal sites of inflammation

To evaluate the factors responsible for the accumulation indium-111 immunoglobulin Gr (¹¹¹InIgG) at sites of inflammation, sequential measurements of tissue blood volume, interstitial fluid volume and accumulation of radiolabelled albumin and IgG were made in rats following Escherichia coli infection in the thigh. Compared with normal thigh muscle, there was two-fold increase in interstitial fluid volume and 1.5-fold increase in plasma and red blood cell volumes in infected muscle. For both proteins, there was a fivefold increase in influx rate constant (kin) in infected muscle. In normal muscle, the interstitial fluid concentration of labelled human serum albumin (¹¹¹In-HSA) was significantly higher than that of ¹¹¹In-IgG (P<0.01). In contrast, the concentrations in infected muscle were nearly identical. The concentration ratios (infected to normal muscle) were 1.7:1 for HSA and 3:1 for IgG. These data suggest that the infection imaging properties of ¹¹¹In-IgG are related to expansion of the space available to macromolecules in infected tissue and increased transport into this space. At clinically important imaging times (24–48 h after injection), the higher target-to-background ratio of ¹¹¹In-IgG compared with ¹¹¹In-HSA is not due to the higher accumulation IgG in infected tissue but rather to the higher accumulation of HSA in normal tissue.Departments of Radiology and Medicine, Harvard Medical School, Boston, Mass., USA Offprint requests to: A.J. Fischman     

Radioactive oxygen-15 in the study of cerebral blood flow, blood volume, and oxygen metabolism

The short half-life of 15O led early observers to believe that it was unsuitable for use as a biological tracer. However, initial studies with this nuclide demonstrated its potential usefulness for in vivo, regional physiologic measurements. Subsequently, techniques were developed to measure cerebral blood flow (CBF), blood volume, and oxygen metabolism using intracarotid injection of 15O-labeled radiopharmaceuticals and highly collimated scintillation probes to record the time course of radioactivity in the brain. The development of positron emission tomography (PET) made possible the in vivo, noninvasive measurement of the absolute concentration of positron-emitting nuclides. A variety of tracer kinetic models were formulated to obtain physiologic measurements from tomographic images of the distribution of 15O-labeled radiopharmaceuticals in the brain. 15O-labeled carbon monoxide, administered by inhalation, binds to hemoglobin in RBCs, and therefore can be used as a intravascular tracer to measure regional cerebral blood volume (rCBV). Several strategies have been developed to measure regional CBF using 15O-labeled water as an inert, diffusible flow tracer. Regional cerebral oxygen metabolism is measured using scan data obtained following the inhalation of 15O-labeled oxygen; independent determinations of local blood flow and blood volume are also required for this measurement. The tracer kinetic models used to measure rCBV, blood flow, and oxygen metabolism will be described and their relative advantages and limitations discussed. Several examples of the use of 15O tracer methods will be reviewed to demonstrate their widespread applicability to the study of cerebral physiology and pathophysiology.     

Regional cerebral blood flow and oxygen metabolism in a patient with Korsakoff syndrome

We report a functional neuroimaging study of a patient clinically diagnosed with Korsakoff syndrome. Positron emission tomography (PET) with the¹⁵O inhalation method showed decreased regional cerebral blood flow (rCBF) and decreased regional cerebral metabolic ratio for oxygen (rCMRO₂) in the bilateral fronto-temporal areas and in the left thalamus. These results suggest that dysfunction of the frontal-thalamic neural network plays a role in the disturbance of Korsakoff syndrome.     

Simultaneous noninvasive determination of regional myocardial perfusion and oxygen content in rabbits: toward direct measurement of myocardial oxygen consumption at MR imaging.

PURPOSE: To determine whether myocardial arterial perfusion and oxygen concentration can be quantified simultaneously from the same images by using spin labeling and the blood oxygenation level-dependent (BOLD) effect with fast spin-echo (SE) imaging. MATERIALS AND METHODS: A T2-weighted fast SE pulse sequence was written to image isolated, arrested, blood-perfused rabbit hearts (n = 6) at 4.7 T. Perfusion images with intensity in units of milliliters per minute per gram that covered the entire left ventricle with 0.39 x 0.39 x 3.00-mm resolution were obtained in less than 15 minutes with a 32-fold reduction in imaging time from that of a previous study. Estimates of oxygen concentration were made from the same images acquired for calculation of perfusion images. RESULTS: Estimates of regional myocardial oxygen content could be made from the perfusion images; this demonstrated the feasibility of three-dimensional calculation of regional oxygen consumption, which requires concomitant measurement of both oxygen content and flow. Fast SE imaging was shown to be as sensitive to hemoglobin desaturation as standard SE imaging. Perfusion abnormalities and oxygen deficits were easily identified and verified qualitatively with gadopentetate dimeglumine on both perfusion and BOLD images obtained after coronary arterial ligation. CONCLUSION: T2-weighted fast SE imaging combined with perfusion-sensitive spin labeling can be used to measure myocardial arterial perfusion and oxygen concentration. This provides the groundwork for calculation of regional myocardial oxygen consumption.     

Regional cerebral blood flow,blood volume,oxygen extraction fraction,and oxygen utilization rate in normal volunteers measured by the autoradiographic technique and the single breath inhalation method

By means of a high resolution PET scanner, the regional cerebral blood flow (rCBF), cerebral blood volume (rCBV), oxygen extraction fraction (rOEF), and metabolic rate of oxygen (rCMRO₂) for major cerebral gyri and deep brain structures were studied in eleven normal volunteers during an eye-covered and ear-unplugged resting condition. Regional CBF was measured by the auto-radiographic method after intravenous administration of H₂ ¹⁵O. Regional OEF and rCMRO₂ were measured by the single inhalation of¹⁵O₂. With MR T₁-weighted images as an anatomical reference, thirteen major cerebral gyri, caudate nucleus, lentiform nucleus, thalamus, midbrain, pons, cerebellum and vermis were defined on the CMRO₂ images. Values were read by using circular regions of interest 16 mm in diameter. The posterior part of the cingulate gyri had the highest rCBF and rCMRO₂ values among brain structures, followed by the lentiform nucleus, the cerebellum, the caudate nucleus, and the thalamus. Parahippocampal gyri had the lowest rCBF and rCMRO₂ values amongthe cortical gyri.RegionalOEFforthepontinenuclei (0.34 ± 0.04), the midbrain (0.35 ± 0.05), the parahippocampal gyri (0.35 ± 0.04 for the right and 0.37 ± 0.05 for the left), and the thalami (0.37 ± 0.05 for the right and 0.36 ± 0.04 for the left) were significantly lower than the mean OEF for the cerebral cortices (0.42 ± 0.04) (p < 0.05 or less). The global CBF and CMRO₂ were consistent with those obtained by the Kety-Schmidt method. Although several limitations to the quantification derived from an inadequate spacial resolution remain unsolved, the performance of the present PET scanner and the method for the quantification employed provide regional estimates of brain circulation and oxygen metabolism more acurately than the PET system and the steady state method previously used.     

Effect of carbohydrate modification on the localization of human polyclonal IgG at focal sites of bacterial infection.

Radiolabeled human polyclonal IgG localizes at focal sites of infection/inflammation. Previous studies have sought to identify the mechanism of localization, but the relative importance of specific antigen recognition by individual antibody molecules, binding to Fc receptors on inflammatory cells and nonspecific processes such as increased tissue permeability remains uncertain. This study was performed to evaluate the specific role of Fc receptor binding as a mechanism of localization. The Fc region of IgG was modified by endoglycosidase-F digestion and periodate oxidation to reduce the binding of IgG to Fc receptors. In-vitro binding was tested in an Fc receptor binding assay using the human monocyte-like cell line, U937. The in-vivo ability of the modified antibodies to localize at focal sites of E. coli infection was tested by biodistribution studied with the 111In-labeled proteins. Modification of the carbohydrate moiety of the Fc region of IgG resulted in a marked decrease in Fc receptor binding in vitro; with antibody concentrations of 1 micrograms/ml (which is presumed to exist at infected sites) showing no binding for endoglycosidase modified IgG and 50% binding for periodate modified IgG. In contrast, in-vivo infection localization as measured by level of accumulation or target-to-background ratio was not significantly effected by carbohydrate modification. These studies suggest that the contribution of Fc receptor binding to IgG localization at sites of infection is minimal.     

Detection of focal renal perfusion defects in rabbits after sulphur hexafluoride-filled microbubble injection at low transmission power ultrasound insonation

The aim of this study was to assess the feasibility of contrast-enhanced ultrasound (US) at low transmission power insonation for diagnosis of focal renal perfusion defects (RPDs) in rabbits. In seven adult New Zealand White rabbits focal RPDs were induced by polyvinyl alcohol embolizing particles (150–250 m in diameter) injected into the abdominal aorta. Three other rabbits that were not subjected to embolization were considered as controls. Both kidneys were insonated at baseline and after injection of sulphur hexafluoride-filled microbubbles at low transmission power (mechanical index 0.09–0.12). One sonologist assessed on-site RPD dimensions and conspicuity (visual score 0–4). Digital cine-clips were also reviewed off-site by two other independent readers, blinded, who assigned a confidence level (grades 1–5) for the RPD diagnosis. At on-site analysis RPDs appeared as focal areas of absent or diminished enhancement with a median visual conspicuity score=4. At off-site analysis RPDs >6 mm in diameter were identified at contrast-enhanced US, and the confidence in RPD diagnosis improved significantly (P<0.05) after microbubble injection (area under receiver operating characteristic curve 0.615 vs 0.972 by reader 1; 0.720 vs 0.953 by reader 2). Contrast-enhanced US at low transmission power insonation effectively identified RPDs with diameters >6 mm in rabbits.Presented as a scientific paper at ECR 2004.     

Developmental changes of cerebral blood flow and oxygen metabolism in children.

BACKGROUND AND PURPOSE: Normal values for cerebral blood flow (CBF) and metabolism in adults are well established, but not for children. Our goal, therefore, was to clarify functional developmental changes of the brain in children in relation to CBF and oxygen metabolism. METHODS: We measured regional CBF (rCBF), regional cerebral metabolic rate for oxygen (rCMRO2), and regional oxygen extraction fraction (rOEF), using positron emission tomography (PET). We performed 30 PET studies in 24 children ages 10 days to 16 years (nine boys, 15 girls), using a steady inhalation method with C(15)O2, (15)O2, and 15CO in order to measure rCBF, rCMRO2, and rOEF, respectively. Regions of interest were set in the primary cerebral areas (sensorimotor, visual, temporal, and parietal cortex), cerebral association areas (frontal and visual association), basal ganglia (lenticular and thalamus), and posterior fossa (brain stem and cerebellar cortex). Subjects were grouped by age (< 1, 1 to < 3, 3 to < 8, and > or = 8 years), and the absolute values of the parameters were compared with those obtained from 10 healthy adults. RESULTS: rCBF and rCMRO2 were lower in the neonatal period than in older children and adults, and increased significantly during early childhood. rCBF was higher as compared with adults, peaking around age 7, whereas rCMRO2 was relatively high, with the last area to increase being the frontal association cortex. Both rCBF and rCMRO2 reached adult values during adolescence. No difference in rCBF was observed between the basal ganglia and the primary cerebral cortex; however, it was prominent in the occipital lobe in every age bracket. No significant changes in rOEF were found during childhood. CONCLUSION: The dynamic changes of rCBF and rCMRO2 observed in children probably reflect the physiologic developmental state within anatomic areas of the brain.     

Dynamic uncoupling and recoupling of perfusion and oxidative metabolism during focal brain activation in man

Changes in glucose consumption, lactate production, and blood oxygenation were measured during prolonged neuronal activation (4–6 min) in human primary visual cortex using dynamic magnetic resonance spectroscopy and imaging. A decrease of steady-state glucose by 40% because of enhanced use by 21% was accompanied by a transient accumulation of lactate with a peak value of 170% 2.5 min after stimulation onset Rapid blood hyperoxygenation indicating ?uncoupling”? of blood flow and oxidative metabolism was followed by a return to basal levels over 3 min. Thus, initial nonoxidative glucose consumption during functional activation is gradually complemented by a slower adjustment of oxidative phosphorylation that ?recouples”? perfusion and oxygen consumption at a new equilibrium.     

高压氧对兔缺血皮瓣模型组织灌注的影响

目的 探索高压氧(HBO)对缺血皮瓣组织灌注的影响.方法 用12只新西兰大白兔建立曾经为文献证实有效的缺血动物皮瓣模型.其中6只兔小进行HBO治疗作为手术对照组.HBO治疗方案为在0.2 MPa压力下吸100%氧气45 min.应用激光多普勒血流仪和经皮测氧仪在手术后即刻、第3天和第7天测定皮瓣的血流、经皮氧分压和二氧化碳分压.用图像分析系统在手术后第3天和第7天评价皮瓣的坏死程度.在术后第3天和第7天切取缺血的皮瓣组织,制成组织切片,HE染色测定新生毛细血管数目.结果 在手术后第3天和第7天,与相应的对照组比较,HBO治疗组的皮瓣坏死面积明显减小(P＜0.05);和对照组比较,在手术后第3天和第7天HBO治疗组皮瓣血流和经皮氧分压明显升高,经皮二氧化碳分压明显降低,差异均有统计学意义(P＜0.05);此外,与相应的对照组比较,皮瓣组织学分析显示HBO组新生毛细血管数目明显增高(P＜0.05).结论 本研究证实,HBO可以促进皮瓣的存活,在挽救缺血皮瓣的过程中,HBO在供给充分的分子氧、促进二氧化碳的排出、促进新生毛细血管的形成、改善皮瓣血流等方面起着重要的作用.     

Cerebral blood flow,blood volume,and vascular permeability of cerebral glioma assessed with dynamic CT perfusion imaging

We report dynamic CT perfusion imaging assessment of hemodynamics in a patient with a high-grade cerebral glioma and compare our results to those of previously published studies.     

Contribution of phagocytic cells and bacteria to the accumulation of technetium-99m labelled polyclonal human immunoglobulin at sites of inflammation

The purpose of this study was to assess the contribution of phagocytic cells and bacteria to the accumulation of technetium-99m labelled polyclonal human immunoglobulin (HIG) at sites of inflammation. Mice were intraperitoneally injected withStaphylococcus aureus (SA animals), with heat-inactivated newborn calf serum (NBCS, to mimic a non-bacterial inflammation) or with physiological saline (controls); 1 h thereafter they received HIG. At various intervals after the administration of HIG the mice were killed, and the percentages of radioactivity in the peritoneal effluent and attached to the cellular and bacterial fraction thereof were established. Furthermore, the total number of cells and that of bacteria in the fluid were quantitated. The percentage of activity in the effluent in the SA animals was (P<0.02) higher than those in the NBCS-injected animals and controls from 4 h onwards. In all groups of mice this percentage was highest at 4 h and decreased (P<0.01) afterwards. The percentage of cell-bound activity and the total number of cells remained fairly constant or increased with time in the SA animals (P<0.01). The bacteria-bound activity remained rather constant throughout the experiment and ranged between 4% and 6%. In the SA-infected animals the percentage of cell-bound activity was correlated with the total number of cells (macrophages but especially neutrophils) but even more strongly with the number of cell-associated bacteria. In the NBCS-injected animals a correlation was demonstrated between the cell-bound activity and the total number of cells (only neutrophils). It is concluded that in both experimental inflammations, phagocytic cells, and especially neutrophils, contributed significantly to the accumulation of label at the site of inflammation. Their impact on this localization is augmented by the phagocytosis of bacteria.     

Reliability of perfusion MR imaging in symptomatic carotid occlusive disease. Cerebral blood volume,mean transit time and time-to-peak

PURPOSE: Perfusion MR imaging offers an easy quantitative evaluation of relative regional cerebral blood volume (rrCBV), relative mean transit time (rMTT) and time-to-peak (TTP). The purpose of this study was to investigate the reliability of these parameters in assessing the hemodynamic disturbance of carotid occlusive disease in comparison with normative data. MATERIAL AND METHODS: Dynamic contrast-enhanced T2*-weighted perfusion MR imaging was performed in 19 patients with symptomatic unilateral internal carotid artery occlusion and 20 control subjects. The three parameters were calculated from the concentration-time curve fitted by gamma-variate function. Lesion-to-contralateral ratios of each parameter were compared between patients and control subjects. RESULTS: Mean +/- SD of rrCBV, rMTT and TTP ratios of patients were 1.089 +/- 0.118, 1.054 +/- 0.031 and 1.062 +/- 0.039, respectively, and those of control subjects were 1.002 +/- 0.045, 1.000 +/- 0.006, 1.001 +/- 0.006, respectively. The rMTT and TTP ratios of all patients were greater than 2 SDs of control data, whereas in only 6 patients (32%), rrCBV ratios were greater than 2 SDs of control data. The three parameter ratios of the patients were significantly high compared with those of control subjects, respectively (p < 0.01 for rrCBV ratios, p < 0.0001 for rMTT ratios, and p < 0.0001 for TTP ratios). CONCLUSION: Our results indicate that rMTT and TTP of patients, in contrast to rrCBV, are distributed in narrow ranges minimally overlapped with control data. The rMTT and TTP could be more reliable parameters than rrCBV in assessing the hemodynamic disturbance in carotid occlusive disease.     

Regional cerebral glucose metabolism and blood flow in a patient with Marchiafava-Bignami disease.

We report functional neuroimaging studies of a 54-year-old man with Marchiafava-Bignami disease (MBD). Glucose metabolic images obtained by [18F]-2-fluoro-2-deoxy-D-glucose positron emission tomography showed diffusely reduced whole brain metabolism and strongly decreased metabolism in the frontal and parietal lobes, orbital gyrus, and thalamus. Cerebral perfusion images showed a similarly decreased radioactivity pattern as the metabolic images. Functional neuroimages would be useful for understanding the pathophysiologic processes of MBD.     

Cerebral blood flow,oxygen and glucose metabolism with PET in progressive supranuclear palsy

Cerebral blood flow, cerebral oxygen metabolic rate and cerebral glucose metabolic rate were measured with positron emission tomography (PET) in four patients with progressive supranuclear palsy (PSP). Decreased blood flow and hypometabolism of oxygen and glucose were found in both subcortical and cortical regions, particularly in the striatum including the head of the caudate nucleus and the frontal cortex. The coupling between blood flow and metabolism was preserved even in the regions which showed decreased blood flow and hypometabolism. These findings indicated the hypofunction, as revealed by decreased blood flow and hypometabolism on PET, both in the striatum and the frontal cortex, and which may underlie the pathophysiological mechanism of motor and mental disturbance in PSP.     

256层CT灌注成像评价兔失神经支配缺血后肢急性期毛细血管床血容量的动态变化

目的 探讨兔失神经支配缺血后肢急性期毛细血管床血容量(blood volume,BV)动态变化及256层CT灌注成像的评估价值.方法 健康成年大耳白兔40只,采用数字表法随机分为联合造模组、缺血组、失神经组和假手术组,每组10只.分别制作右后肢股动脉切除联合股神经离断、单纯股动脉切除、单纯股神经离断及单纯分离股动脉假手术模型.于术后第1、7、14、21和28天行256层CT灌注扫描,计算各组右后肢与左后肢肌肉组织的BV比值(rBV).于术后第14和28天各组采用数字表法随机处死动物4只,分别切取双侧内收肌进行免疫组织化学染色,计算右后肢与左后肢内收肌毛细血管密度比值(rMVD).各组不同时点rBV采用2×2析因设计方差分析,采用Pearson相关分析rBV与内收肌rMVD的相关性.结果 术后第1天,联合造模组、缺血组、失神经组和假手术组rBV分别为0.31 ±0.15(6只)、0.29±0.12(6只)、0.98±0.08(6只)、0.98±0.07(6只),术后第7天分别为1.69±0.45(5只)、1.63±0.43(6只)、0.99±0.07(6只)、1.00±0.08(6只),术后第14天分别为1.58±0.18(5只)、1.49±0.25(6只)、0.94±0.08(6只)、1.01±0.05(6只),术后第21天分别为1.42±0.41(4只)、1.43 ±0.31(4只)、0.94 ±0.05(5只)、1.02±0.05(5只),术后第28天分别为1.00±0.25(4只)、0.99±0.08(4只)、0.92±0.09(5只)、1.02±0.13(5只),除术后第28天外(F(A)=0.214,P>0.05),缺血因素对灌注参数rBV的影响具有主效应(F(A)值分别为274.268、30.044、65.787、18.886,P值均<0.01),而单纯失神经因素在各时点均未表现出主效应,两因素在各时点均无交互作用.各组rMVD支持上述改变;rBV与rMVD的相关系数为r=0.862(P<0.01).结论 兔后肢缺血后急性期毛细血管床血流灌注表现呈动态变化,合并失神经支配时,并未影响此过程.256层CT可以无侵袭性、半定量评估兔失神经缺血后肢急性期毛细血管床的动态变化.     

256层CT灌注成像评价兔失神经支配缺血后肢急性期毛细血管床血容量的动态变化

Objective To investigate the capillary blood volume (BV) changes in acute ischemic denervated hindlimb of rabbits and the value of 256-slice detector computed tomography (CT) perfusion imaging in evaluation.Methods A total of 40 healthy, adult white rabbits underwent either right hindlimb femoral artery excision combined femoral nerve denervation (combined modeling group, n = 10), simple femoral artery excision (iachemia group, n = 10), simple femoral nerve denervation (denervation group,n = 10), or simple femoral artery separation (sham-surgery group, n = 10).At 1,7, 14, 21, and 28 days following surgery, CT perfusion scanning (Philips Brilliance 256-row) was performed and CT perfusion images were processed using maximum-slope method with Function CT software on EBW workstation.The ratio of BV (rBV) in muscle tissue between right and left hindlimbs was calculated in each group.At 14 and 28 days, following sacrifice, rabbit bilateral adductor was harvested for immunohistochemical staining.The ratio of microvessei density (rMVD) in muscle tissue between right and left hindlimbs was calculated.The significance of the difference of rBV at each time point was assessed using analysis of variance of factorial design (2 ×2).Pearson correlation analysis was used to study the relationship between rBV and rMVD.Results After surgery, the 1st day rBV of combined modeling group, combined modeling group,denervation group and sham-surgery group is 0.31 ± 0.15 ( n = 6), 0.29 ± 0.12 (n = 6), 0.98 ± 0.08 ( n =6), 0.98 ± 0.07 ( n = 6) respectively.The 7th day following surgery rBV is 1.69 ± 0.45 ( n = 5 ), 1.63 ±0.43(n=6), 0.99 ±0.07(n =6), 1.00 ±0.08(n =6).The 14th day is respectively 1.58 ±0.18(n=5), 1.49 ±0.25(n =6), 0.94 ±0.08(n =6), 1.01 ±0.05(n =6).The 21th day is 1.42 ±0.41 (n=4),1.43 ±0.31(n=4), 0.94 ±0.05(n =5), 1.02 ±0.05(n =5),and the 28th day is 1.00 ±0.25(n=4),0.99 ±0.08(n=4), 0.92 ±0.09(n =5), 1.02 ±0.13(n=5).At each time point with exception of postoperative 28 days(F(A) =0.214,P>0.05), ischemia produced main effects on rBV(F(A) =274.268,30.044,65.787,18.886 ,P < 0.01 ), while simple denervation did not show main effects on each time point.Ischemia and denervation did not yield interaction effects on each time point, rMVD from each group supported above-mentioned changes.The correlation coefficient of rBV to rMVD was r = 0.862 ( P < 0.01 ).Conclusions BV in acute ischemic denervated hindlimb of rabbits shows a dynamic change, and denervation does not obviously influence this process.256-slice detector CT perfusion imaging can be used to noninvasively and semi-quantitatively evaluate the dynamic changes of capillary bed in acute ischemie denervated hindlimb of rabbits.     

256层CT灌注成像评价兔失神经支配缺血后肢急性期毛细血管床血容量的动态变化

Objective To investigate the capillary blood volume (BV) changes in acute ischemic denervated hindlimb of rabbits and the value of 256-slice detector computed tomography (CT) perfusion imaging in evaluation.Methods A total of 40 healthy, adult white rabbits underwent either right hindlimb femoral artery excision combined femoral nerve denervation (combined modeling group, n = 10), simple femoral artery excision (iachemia group, n = 10), simple femoral nerve denervation (denervation group,n = 10), or simple femoral artery separation (sham-surgery group, n = 10).At 1,7, 14, 21, and 28 days following surgery, CT perfusion scanning (Philips Brilliance 256-row) was performed and CT perfusion images were processed using maximum-slope method with Function CT software on EBW workstation.The ratio of BV (rBV) in muscle tissue between right and left hindlimbs was calculated in each group.At 14 and 28 days, following sacrifice, rabbit bilateral adductor was harvested for immunohistochemical staining.The ratio of microvessei density (rMVD) in muscle tissue between right and left hindlimbs was calculated.The significance of the difference of rBV at each time point was assessed using analysis of variance of factorial design (2 ×2).Pearson correlation analysis was used to study the relationship between rBV and rMVD.Results After surgery, the 1st day rBV of combined modeling group, combined modeling group,denervation group and sham-surgery group is 0.31 ± 0.15 ( n = 6), 0.29 ± 0.12 (n = 6), 0.98 ± 0.08 ( n =6), 0.98 ± 0.07 ( n = 6) respectively.The 7th day following surgery rBV is 1.69 ± 0.45 ( n = 5 ), 1.63 ±0.43(n=6), 0.99 ±0.07(n =6), 1.00 ±0.08(n =6).The 14th day is respectively 1.58 ±0.18(n=5), 1.49 ±0.25(n =6), 0.94 ±0.08(n =6), 1.01 ±0.05(n =6).The 21th day is 1.42 ±0.41 (n=4),1.43 ±0.31(n=4), 0.94 ±0.05(n =5), 1.02 ±0.05(n =5),and the 28th day is 1.00 ±0.25(n=4),0.99 ±0.08(n=4), 0.92 ±0.09(n =5), 1.02 ±0.13(n=5).At each time point with exception of postoperative 28 days(F(A) =0.214,P>0.05), ischemia produced main effects on rBV(F(A) =274.268,30.044,65.787,18.886 ,P < 0.01 ), while simple denervation did not show main effects on each time point.Ischemia and denervation did not yield interaction effects on each time point, rMVD from each group supported above-mentioned changes.The correlation coefficient of rBV to rMVD was r = 0.862 ( P < 0.01 ).Conclusions BV in acute ischemic denervated hindlimb of rabbits shows a dynamic change, and denervation does not obviously influence this process.256-slice detector CT perfusion imaging can be used to noninvasively and semi-quantitatively evaluate the dynamic changes of capillary bed in acute ischemie denervated hindlimb of rabbits.