彩色多普勒血流显像及多普勒能量图在移植肾排斥反应中的应用

目的探讨彩色多普勒血流显像及多普勒能量图在检测移植肾排斥反应中的应用价值。方法对46例肾移植受者术后进行了彩色多普勒血流显像及多普勒能量图检查。根据检测结果将46例肾移植术后受者分为3组,移植肾正常组(30例)、急性排斥组(9例)和慢性排斥组(7例),并与超声引导下肾组织穿刺的病理检查结果进行比较。结果16例急、慢性排斥反应的患者移植肾动脉搏动指数及阻力指数均高于移植肾正常组;急性排斥组肾脏长径及肾皮质厚度明显大于移植肾正常组;慢性排斥反应时肾皮质厚度、肾脏长径、宽径均小于移植肾正常组。结论彩色多普勒血流显像及多普勒能量图对移植肾血流灌注及排斥反应判断有独特的优点,搏动指数、阻力指数以及肾皮质厚度可作为有无移植肾排斥的指标之一。     

Evaluation of renal cortical perfusion by noninvasive power Doppler ultrasound during vascular occlusion and reperfusion

BACKGROUND: Urine output, a frequently used resuscitation end point, is presumed to represent renal cortical perfusion. However, no noninvasive method for direct measurement of renal perfusion exists. Power Doppler ultrasound (PDUS) is a method that reportedly is sensitive to low-velocity and microvascular blood flow and can depict it. This study aimed to develop a quantitative technique for PDUS image analysis, and to evaluate the ability of PDUS to quantify cortical perfusion during renal ischemia induced by vascular occlusion. METHODS: A method was developed to determine the mean gray-scale intensity of PDUS images from within the renal cortex (PDUS image intensity). This index was hypothesized to represent renal cortical microvascular blood flow. Renal cortical blood flow was determined using fluorescent microspheres in five swine. Renal artery flow was measured with an ultrasonic flow probe. Power Doppler ultrasound was performed at baseline; at 75%, 50%, and 25% of baseline renal artery flow; and during reperfusion. RESULTS: Subjectively, PDUS images showed decreases in image intensity corresponding to renal artery occlusion and increases after reperfusion. Cortical blood flow correlated well with renal artery flow (n = 25; r2 = 0.868) and with PDUS image intensity (n = 25; r2 = 0.844). CONCLUSION: Noninvasive power Doppler ultrasound image intensity correlated well with invasively measured renal cortical blood flow, and may be useful during resuscitation of injured and critically ill patients.     

Evaluation of canine renal transplants with pulsed Doppler duplex sonography

Preliminary studies of human renal transplants suggested that pulsed Doppler sonography may complement other studies of renal transplant dysfunction. To further evaluate the Doppler technique, 11 dogs who received renal transplants were examined a total of 50 times. No antirejection chemotherapy was used, and following rejection the kidneys were removed and examined histologically. The canine transplants underwent accelerated acute or hyperacute rejection. A pulsed Doppler index (PDI) was derived to quantitate patterns of renal blood flow and peripheral vascular resistance. Arterial Doppler signals were obtained from renal transplant branch vessels in vivo and the PDI consistently fell as rejection occurred. No arterial signals were obtained from one kidney which was subsequently proven to have arterial thrombosis. Pulsed Doppler analysis provides new information about renal transplant blood flow patterns and may demonstrate evidence of rejection and renal arterial occlusion.     

Intra- and post-operative assessment of renal cortical perfusion by laser Doppler flowmetry in renal transplantation in the rat

Renal blood flow (RBF) in the period immediately following transplantation has an important prognostic value. Here we report for the first time on the use of laser Doppler flowmetry (LDF) for the measurement of renal cortical perfusion (RCP) during all the important steps in renal transplantation. Left orthotopic kidney transplantation was performed in Lewis rats (n = 14) after 2 h of cold ischaemia and preservation in EuroCollins solution. Under baseline conditions, RCP in the donor and recipient kidneys were similar with a coefficient of variability of 11 and 12%, respectively. There was a progressive increase in RCP during the first 60 min after transplantation with a return to normal values 2 weeks later. In conclusion, LDF provides a rapid and continuous measure of RCP without interference to the operative site and may prove a useful tool for the measurement of RBF during kidney transplantation.     

Use of power Doppler ultrasound to monitor renal perfusion during burn shock

BACKGROUND: Renal cortical blood flow can be quantified by means of power Doppler ultrasound (PDUS) image analysis. We hypothesized that renal cortical perfusion, estimated by PDUS image intensity (PDUSII), would decrease during burn shock and improve during resuscitation in a porcine model. METHODS: Eight anesthetized swine sustained a 75% scald injury. Resuscitation began 6h postburn. Renal cortical blood flow was measured directly using fluorescent microspheres (CORFLO), and was estimated noninvasively by PDUSII. PDUSII, CORFLO, and cardiopulmonary data were recorded every 2h. RESULTS: PDUSII decreased significantly from preburn to postburn hour 6, and increased with resuscitation by hour 8. CORFLO correlated well with PDUS image intensity (n=48, r(2)=0.696) but poorly with urine output (n=48, r(2)=0.252). CONCLUSION: PDUS in this study was superior to the urine output in assessing renal cortical microvascular blood flow during shock and resuscitation, and may be useful in the care of injured patients.     

Quantitative estimation of renal blood flow by power Doppler ultrasonography in renovascular hypertensive dogs

BACKGROUND: We estimated the value of power Doppler (PD) imaging analysis for the quantitative assessment of renal cortical blood flow (RCBF) in chronic two-kidney, one-clip (2K-1C) hypertensive dogs. METHODS: To evaluate the correlation between RCBF and PD signals, RCBF and the mean pixel intensity (MPI) of PD signals were simultaneously obtained at same region in renal cortex under progressive constriction of left main renal artery in five mongrel dogs. RCBF was measured by electrolytic hydrogen gas clearance method, and PD images were transferred to computer and analyzed by the image-analysis software Openlab. To assess the value of quantitative PD imaging analysis on RCBF in renovascular hypertension, in six mongrel dogs with chronic 2K-1C hypertension, PD images in both of clipped kidneys (CK) and non-clipped kidneys (NK) were obtained and analyzed before and 60 minutes after the intravenous infusion of captopril or sodium nitroprusside at 10-minute intervals. RESULTS: There was a linear correlation between RCBF and MPI (r= 0.878, P < 0.0001). MPI in both CK and NK significantly increased after the infusion of captopril, while no significant change was observed in both CK and NK after the infusion of sodium nitroprusside, despite similar reduction of mean arterial blood pressure. CONCLUSION: Our data suggest that the acute inhibition of angiotensin-converting enzyme increased RCBF in both CK and NK of chronic 2K-1C dogs. The quantitative analysis of PD flow signals in kidney is noninvasive and a useful method to evaluate regional changes of renal tissue blood flow in various renal diseases.     

Renal blood flow measurement with contrast-enhanced harmonic ultrasonography: evaluation of dopamine-induced changes in renal cortical perfusion in humans

BACKGROUND: An accessible non-invasive method for evaluating renal regional blood flow in real time is highly desirable in the clinical setting. Recent progress in ultrasonography with microbubble contrast has allowed quantification of regional blood flow in animal models. AIMS: Goal ofthis study was to establish a convenient contrast--enhanced harmonic ultrasonography (CEHU) method for evaluating renal cortical blood flow in humans. METHODS: We carried out intermittent second harmonic imaging in 9 healthy volunteers. Pulse interval was progressively decreased from 4 s - 0.2 s during continuous venous infusion of the microbubble contrast agent. RESULTS: Pulse interval versus CEHU-derived acoustic intensity plots provided microbubble velocity (MV) and fractional vascular volume (FVV) during renal cortical perfusion in humans. Low-dose dopamine infusion (2 microg/min/kg) resulted in a significant increase in MV which correlated well with the increase in total renal blood flow (RBF) determined by a conventional study of p-aminohippurate clearance (C(PAH)) (r = 0.956, p < 0.0001). Although FVV was not significantly increased, alterations in CEHU-derived renal cortical blood flow calculated by the products of MV and FVV were also correlated with alterations in total RBF (r = 0.969, p < 0.0001). Thus, low-dose dopamine infusion increases renal cortical blood flow observed in CEHU, mainly by increasing MV. CONCLUSIONS: The present study shows that renal cortical blood flow in humans can be measured non-invasively by CEHU and that CEHU can be used for quantitatively evaluating changes induced by a therapeutic agent such as dopamine in flow velocity and in FVV.     

Predictive value of Doppler ultrasonography in renal transplantation

During a 17-month period, 268 Doppler sonography studies were performed on 46 consecutive renal transplant patients. There were 35 episodes of acute rejection in 10 patients, 8 episodes of delayed function and 47 episodes of high cyclosporine levels (greater than 800 ng/dl by TDX method) in 21 patients. Defining an abnormal resistive index (RI) as greater than 0.8 or a 20% increase above baseline, the test has a specificity of 99% and a sensitivity of 94% in the 1st month post-transplant and had an overall predictive value of 99%. Episodes of high cyclosporine levels ranging from 800 to 1650 ng/dl did not correlate with a high RI except in one circumstance with concurrent acute rejection. Within the 1st month post-transplant, only 1 false-negative study occurred. An additional 8 false-negative studies occurred beyond 1 month post-transplant. Patients with delayed function are separated into three groups based on the Doppler ultrasounds: Group I, patients with an accelerated acute rejection with high RI (N = 2); Group II, patients with true ischemic acute tubular necrosis with normal RI (N = 2); and Group III, patients with possible immunologically-mediated delayed function with intermediate RI between 0.6 and 0.8 (N = 4). Doppler ultrasound is a useful ancillary test to confirm the clinical suspicion of acute rejection. Since high cyclosporine levels do not cause an increase in RI, Doppler ultrasound may help to avoid confusion between acute rejection and cyclosporine toxicity. Additionally, this test may offer insight into the cause of early post-transplant renal dysfunction.     

Value of duplex Doppler ultrasonography in renal colic

OBJECTIVES: The aim of our study was to determine the value of duplex Doppler ultrasonography (DDU) in the patients' evolution with renal colic. The study of the resistive index (RI), difference of the RI (ARI) associated with a DDU intravesical recording (ureteral jets) were compared with renographic findings in renal colic. PATIENTS AND METHODS: Between October 1998 and January 2001 we studied 377 cases with suspected renal colic by intravenous pyelography (IVP), grey-scale ultrasonography and DDU with determination of the RI, the difference between the RI of ipsilateral and contralateral kidneys (ARI) and the amplitude (maximum length of the intravesical ureteral jet), velocity and frequency of the urine bolus. We considered normal values RI < or = 0.70 and ARI < or = 0.06. VP was used as a referee investigation and the ureteral intravesical jets were determined in standard conditions. All patients came to the hospital between 4 and 12 h after the onset of the renal colic. RESULTS: We found four series of patients: 1, acute (complete) obstructed kidney (IVP nonfunctional) and dilatation at normal grey-scale, with normal contralateral kidney (n = 153). In this series we found RI > 0.70 in 87%, RI > 0.06 in 90% and absent ureteral intravesical jet of the obstructed kidney site in 89%; 2, acute (complete) obstructed kidney (IVP nonfunctional) without abnormalities at normal grey-scale, with normal contralateral kidney (n = 57). In this series we found RI > or = 0.70 in 73.5%, deltaRI > 0.06 in 82.5% of patients, absent or asymmetric ureteral intravesical jet in 80.7% of cases; 3, incomplete obstructed kidney (IVP with various degree of ureterohydronephrosis) with normal contralateral kidney (n = 96). In this series we found RI > or = 0.70 in 58.3% and deltaRI > 0.06 in 64.5% of patients, asymmetric ureteral intravesical jets in 74% of cases; 4, normal both kidneys normal IVP) were found in 71 cases (18.8%). In this series we found RI < 0.70 in 80.2%, deltaRI < or = 0.06 in 89% of cases, normal ureteral intravesical jets in 93% of cases. The mean RI was 0.76 (0.05) in 306 obstructed kidneys, significantly higher than the mean RI of 0.62 (0.05) in 448 normal kidneys (P < 0.001). The ARI in patients with obstruction was significantly higher than in patients with normal both kidneys, at 0.08 (0.05) and -0.001 (0.03), respectively (P < 0.001). The RI was sensitive in 75.5% and specific in 92.5% and ARI was sensitive in 80.7% and specific in 95.7% (versus IVP, considered the referee value). The presence of the intravesical ureteral jets of the renal colic side, associated with the values of RI (RI < or = 0.70) and deltaRI (deltaRI < or = 0.06), was followed by spontaneous passage of the stones in 71% of cases. CONCLUSIONS: Renal DDU and consecutively, intravesical evaluation of ureteral jets could detect acute renal obstruction and, as a functional investigation, could have a predictive value regarding the ureteral stones passage. It could replace the IVP, being a sensitive and highly specific test.     

Clinical implications of power Doppler three-dimensional ultrasonography

Power Doppler ultrasonography displays an estimate of the entire power contained in that part of the received radiofrequency ultrasound signal for which a phase shift corresponding to the motion of the target is detected. In contrast, conventional color Doppler imaging displays Doppler frequency shift information. Few reports have been published on the clinical utility of three-dimensional power Doppler ultrasonography in vascular patients. This study analyzed our experience of the clinical utility of this technology. Fifty-three patients selected out of 281 who were referred to our vascular laboratory underwent both conventional color duplex ultrasonography and power Doppler ultrasonography for the following indications: the question of subtotal versus total arterial occlusion, tortuous artery with limited imaging on color duplex ultrasonography, the presence of significant disease by Doppler ultrasonography with limited imaging, deep-lying arteries with an obscure orifice (e.g., renal artery), and heavily calcified arteries. The power Doppler ultrasonography portion of the examination was considered of positive diagnostic value if the final impression was different from that of conventional color duplex ultrasonography. A positive diagnostic value was achieved in 22 of 29 (76%) carotid artery examinations, 10 of 14 (71%) peripheral artery examinations, 4 of 5 (80%) renal artery examinations, and 3 of 5 (60%) aortoiliac examinations. Overall, positive diagnostic value was achieved by adding power Doppler ultrasonography in 39 of 53 patients (74%). Five of six patients (83%) who were felt to have carotid occlusion by color duplex ultrasonography were confirmed to have subtotal occlusion by power Doppler ultrasonography. Similarly, 6 of 8 patients (75%) with questionable subtotal versus total peripheral arterial occlusion by color duplex ultrasonography were confirmed to have subtotal occlusion by power Doppler ultrasonography. Four of five patients' (80%) renal examinations had a positive diagnostic value, which included three patients in whom the orifice of renal arteries was not seen by color duplex ultrasonography. Three-dimensional power Doppler ultrasonography can be more readily applied to clinical practice. Power Doppler ultrasonography is capable of defining the severity or extent of vascular disease, particularly in differentiating subtotal from total arterial occlusion.     

Dynamic tissue perfusion measurement: a novel tool in follow-up of renal transplants

BACKGROUND: The authors applied the novel method of noninvasive dynamic color Doppler sonographic parenchymal perfusion measurement to renal transplants. METHODS: Color Doppler sonographic videos of renal transplants from 38 renal transplant recipients were recorded under defined conditions. Specific tissue perfusion was calculated as mean flow velocity encoded by color Doppler signals of a region of interest during one full heart cycle. RESULTS: The authors could demonstrate significant differences of central versus peripheral cortical perfusion intensity (1.36 vs. 0.60 cm/sec) and a significant loss of perfusion intensity in the posttransplantation period in the peripheral cortex from 1.06 cm/sec in the first year to a minimum of 0.39 cm/sec in the 3- to 5-year interval, with stronger perfusion in longer surviving transplants: 0.71 cm/sec more than 9 years after transplantation. In the central cortex, a similar but less pronounced pattern could be demonstrated. A significant drop of parenchymal perfusion was found in patients with elevated serum creatinine (1.36 cm/sec in cases with normal and 0.82 cm/sec in those with elevated creatinine at the proximal cortical level). The perfusion ratio of the central 50% and the peripheral 50% shows marked changes over time: in the first year, the ratio was 2.99, climbing to 5.56 at the 3- to 5-year interval and declining later on. CONCLUSIONS: Cortical tissue perfusion in renal transplants was quantified noninvasively from color Doppler signal data in an easily accomplishable manner. Renal transplants showed a marked decline in tissue perfusion after transplantation. Perfusion is significantly lower in transplant function loss with elevated serum creatinine.     

Usefulness of power Doppler ultrasonography in evaluating erectile dysfunction

OBJECTIVE: To evaluate deep penile arterial flow after an intracavernosal injection with papaverine in patients with erectile dysfunction (ED). PATIENTS AND METHODS: Twenty patients with ED were evaluated using power Doppler ultrasonography with a linear probe (8 MHz). Diagnostic tests were undertaken after an intracavernosal injection with 40 mg papaverine. The peak systolic velocity (PSV), end-diastolic velocity (EDV) and resistive index (RI) were analysed. RESULTS: After injecting papaverine, seven patients had a normal erection and appropriate waveform patterns; their mean PSV was 30.7 cm/s, the EDV 4.42 cm/s and the RI 0.85. There was tumescence and elongation of the penis with no rigidity in eight patients; their mean PSV was 23.9 cm/s, the EDV 7.34 cm/s and the RI 0.72. There was no erection in five patients. The abnormal flow values showed insufficient arterial vessels in a quarter of the men, venous leakage in 15% and mixed ED in 20%. CONCLUSION: The power Doppler technique allows the accurate location and evaluation of deep penile arteries. Vascular pathology may be differentiated after an intracavernosal injection with a vasomotor agent. Recognising the pathological pattern assists in choosing the best method of treatment.     

彩色多普勒超声诊断肾动脉瘤

目的探讨彩色多普勒超声诊断肾动脉瘤的价值。方法回顾性分析经CTA或手术证实的5例肾动脉瘤超声表现,评价病变大小、边界、位置、内部回声及血流特点。结果 4例经超声检查获得准确定位及诊断,1例误诊为胰尾囊肿;灰阶超声显示动脉局限性扩张呈球形或梭形,内部均匀无回声,其中1例瘤壁附着血栓,呈低回声;CDFI显示瘤体内部血流为涡流;PWD显示瘤体内部为动脉血流频谱。结论肾动脉瘤超声表现具有特征性,灰阶超声结合CDFI及PWD对于诊断肾动脉瘤具有重要价值。     

移植肾术后肾动脉闭塞的彩色多普勒超声表现

目的 探讨彩色多普勒超声对移植肾术后肾动脉闭塞的的诊断价值.方法 回顾分析3例经临床证实的肾移植术后动脉闭塞的彩色多普勒超声表现.结果 1例肾动脉主干及其分支完全闭塞,2例移植肾内多支段动脉及其分支闭塞,仅见一支段动脉充盈.结论 移植肾术后肾动脉闭塞的彩色多普勒超声表现对早期诊断具有重要意义.     

彩色多普勒超声在肾移植后排斥反应诊断中的应用

目的 探讨彩色多普勒超声在移植肾排斥反应监测中的应用价值。方法 对68例肾移植患者采用彩色多普勒超声进行监测，观察移植肾的结构及体积、肾皮质厚度、肾动脉内径、血流灌注情况、血流动力学参数。结果术后随访最长者达4年，45例移植肾功能正常，未发生排斥反应者，其移植肾在彩色多普勒超声下表现为边界清晰，肾内结构清楚，皮、髓质界限分明，血流丰富。13例发生急性排斥反应者，彩色多普勒超声下可见移植肾明显肿大，肾实质血流信号稀少，叶间动脉呈断续闪烁状，弓形动脉几乎无血流信号。10例发生慢性排斥反应者，彩色多普勒超声下可见移植肾体积缩小，皮质变薄，肾皮质与肾髓质界限不清，肾内血管分枝稀疏，血管树不连续，弓形动脉及小叶间动脉往往不显示，为低速高阻血流。血流动力学参数显示，发生急性排斥反应者的肾动脉阻力指数及搏动指数明显增高，舒张期峰值流速减低；发生慢性排斥反应者的肾动脉内径明显缩小，收缩期峰值流速及舒张期峰值流速明显减低，血流灌注量明显减少，阻力指数及搏动指数明显升高，与肾功能正常者比较，差异均有统计学意义。结论对于肾移植患者的术后监测，彩色多普勒超声具有独特的优点，无创、便捷，其所测得的移植肾形态学数据和血流动力学参数对排斥反应的判断具有重要参考价值，可作为肾移植术后的常规峪测手段。     

Effect of graded hemorrhage on renal cortical perfusion in dogs

Renal cortical tissue gas tensions, systemic oxygen supply and some features of energy metabolism and central hemodynamics were recorded in splenectomized dogs during graded hemorrhage and subsequent reinfusion of shed blood. Renal cortical partial pressure of oxygen and carbon dioxide responded rapidly to changes in blood volume and cardiac output. Lowest cortical partial pressure of oxygen values and highest cortical partial pressure of carbon dioxide levels were achieved at a maximal 50 percent blood loss. The decrease in arterial pressure, blood hemoglobin and hematocrit as well as the increase in blood lactate concentration lagged behind blood loss. Renal cortical partial pressure of oxygen, arterial pressure and cardiac output responded rapidly to reinfusions of withdrawn blood, while the cortical partial pressure of carbon dioxide, heart rate, arterial pH and blood lactate concentration returned to initial levels more slowly. Arterial blood gases remained normal throughout the observation period and did not provide an adequate index of tissue oxygenation. In contrast, the partial pressure of oxygen of the renal cortex proved an excellent and sensitive indicator of renal perfusion during hemorrhagic shock and its management.     

Effects of sildenafil on ocular perfusion demonstrated by color Doppler ultrasonography

The aim of this study was to investigate the effects of sildenafil on ocular hemodynamics by color Doppler ultrasonography (CDU). In all, 38 patients with erectile dysfunction diagnosed by International Index of Erectile Function (IIEF) and Sexual Health Inventory of Men (SHIM) scores were included into the study. After taking 100 mg of oral sildenafil citrate, all patients underwent CDU examination of central retinal artery at 60 and 75 min and CDU examination of cavernosal artery at 20, 60 and 75 min. All of the side effects during and after the test were also recorded. The mean cavernous artery peak systolic flow velocity increased significantly after sildenafil. However, no significant change was determined in central retinal artery flow parameters including peak systolic flow velocity, end-diastolic flow velocity, resistive index, pulsatility index, volume and diameter. Five patients experienced ocular side effects. No significant change was observed in retinal artery CDU measurements of patients having ocular side effects. Sildenafil has no effect on ocular hemodynamics on the basis of CDU. Ocular side effects may be the result of other changes in retinal photoreceptors rather than the ocular circulation.