Duplex sonography of normal renal allografts

Thirty-five patients with normal renal allografts as well as 10 healthy volunteers with normal native kidneys were examined by duplex sonography. Blood flow measurements were performed in the main renal artery as well as in segmental, interlobar and arcuate arteries. In both groups the normal range of variation in blood flow was defined by using the resistive index (RI). Doppler wave forms and RI of main renal arteries were both similar to those of their branches. In renal allografts as well as in native kidneys the blood flow pattern showed a rapid up-slope in systole followed by a gradual down-slope in early diastole, with a persistent flow throughout diastole. In addition, there was no significant difference in the RI between allografted and native kidneys. The interobserver variability was less than 10 per cent. The mean RI was 0.68 using all data points. Vascular rejection in 11 patients could be discriminated significantly (p less than 0.001). Duplex sonography is useful in evaluating renal blood flow. This simple and non-invasive technique seems to be useful in long-term follow-up of renal allograft recipients.     

彩色多普勒超声对隐匿性糖尿病肾病各级肾动脉的观察

目的:探讨彩色多普勒超声对隐匿性糖尿病肾病的诊断价值。方法:对隐匿性糖尿病肾病72例(观察组)、临床蛋白尿组63例、肾衰组47例行彩色多普勒超声检查,分别与正常对照组30例对比双肾主动脉、叶间动脉的收缩期峰值流速(Vmax)、舒张期流速(Vmin)、阻力指数(RI)及双肾大小。结果:观察组、临床蛋白尿组及肾衰组的肾主动脉、叶间动脉的阻力指数均较对照组有较大差异(P<0.05,P<0.01),观察组的肾主动脉及叶间动脉的舒张期流速明显降低(P<0.01),临床蛋白尿组的肾主动脉舒张期流速、叶间动脉的收缩期及舒张期流速均降低(P<0.01),肾衰组的肾主动脉、叶间动脉的收缩期及舒张期流速均降低(P<0.01);观察组、临床蛋白尿组双肾大小较对照组测值略大,但差异无统计学意义(P>0.05),肾衰组与各组之间比较均有较大差异(P<0.01)。结论:彩色多普勒超声检测糖尿病患者肾血管血流参数的变化对早期诊断隐匿性糖尿病肾病有一定价值。     

运动过程中人肾脏血流动力学超声特点

目的：探究在运动过程中人肾脏血流动力学的改变。方法选取我军某部216名战士进行5公里越野训练,作为实验组;同时选取60名平静状态下的战士作为对照组。应用彩色多普勒超声仪检查2组受检者的肾脏血流灌注情况及肾脏各级动脉血流动力学参数,包括收缩期峰值血流速度（PSV）、舒张末期血流速度（EDV ）、血管阻力指数（RI）、血管搏动指数（PI）。结果实验组肾主动脉、段动脉、叶间动脉的PSV、RI、PI均较对照组减低,具有统计学意义。结论超声检查可以反映运动条件下人三级肾动脉的血流动力学改变,可为研究人体运动所引起的血流动力学的变化及其与肾功能方面的关系。     

Duplex Doppler analysis of interlobular arteries in transplanted kidneys

The aim of our study was to analyze changes in spectral Doppler waveforms between interlobar and interlobular arteries in renal transplants and to determine whether sampling location at interlobular level can be suitable for intrarenal resistive index (RI) measurements. Paired series of spectral tracings from interlobar arteries and respective interlobular branches were obtained in 62 consecutive renal transplants at 6.5-MHz Doppler frequency. The values of peak systolic velocity (PSV), end diastolic velocity (EDV) and RI were significantly (P < 0.01) reduced when calculated at interlobular level. In 38 % of cases, an interlobar RI higher than 0.70 corresponded to a normal interlobular RI. The values of PSV, EDV, and RI did not differ significantly at interlobular level between allograft subsets with normal and elevated serum creatinine level. Both intra- and interobserver variation were higher at interlobular than at interlobar level when performing the RI. During a conventional study of renal vasculature, an underestimation of abnormal RI findings can be expected from the incidental evaluation of interlobular tracings. We recommend sonologists to pay attention in accurately locating the sample volume at interlobar–arcuate level when evaluating intrarenal RI. Received 30 December 1996; Revision received 16 May 1997; Accepted 3 September 1997     

Doppler evaluation of renal transplants in children: a prospective analysis with histopathologic correlation

Duplex Doppler sonography recently has been used to evaluate renal transplants. Some authors have stated that high resistive indexes (RIs) occur in the presence of acute renal transplant rejection. RIs less than 0.7 are considered as probably excluding acute transplant rejection. We performed a prospective study of duplex sonographic examinations of pediatric patients (mean age, 8 years; 13 boys, two girls) with renal allografts and clinically suspected transplant disease. The results of 22 duplex studies were correlated with histopathologic data obtained between July 1987 and June 1988. RIs of the arcuate arteries in patients with acute rejection (n = 14) averaged 0.62 (range, 0.50-0.80). The RI in patients with chronic rejection (n = 1) was 0.59. RIs in patients with acute tubular necrosis (n = 3) averaged 0.66 (range, 0.59-0.72). RIs in patients with cyclosporine A toxicity (n = 4) averaged 0.66 (range, 0.58-0.79). Tubulointerstitial rejection was predominant, with only two patients showing minimal acute vascular rejection. Thirteen of 14 pediatric patients with histologically proved renal transplant rejection had a resistive index of less than 0.70. This study refutes the concept that resistive indexes of less than 0.7 exclude acute rejection.     

Apparent diffusion coefficient of renal parenchyma and color Doppler ultrasound of intrarenal arteries in patients with cirrhosis related renal dysfunction

Objectives

The aim of this work was to study the renal hemodynamic changes which occur with liver cirrhosis using diffusion weighted magnetic resonance imaging (DW-MRI) and renal color duplex Doppler ultrasound.

Patients and methods

Patients were divided into four groups: Group A: 15 cirrhotic patients with compensated liver cirrhosis, Group B: 15 cirrhotic patients with refractory ascites, Group C: 15 cirrhotic patients with hepatorenal syndrome, Group D: 10 healthy persons as a control. The apparent diffusion coefficient (ADCs) of the kidneys was calculated using low b values (ADC_low) and high b values (ADC_high). Color Doppler ultrasound was performed in interlobar and arcuate arteries to calculate resistive index (RI) and pulsatility index (PI) in all patients.

Results

ADC_low showed a statistically significant difference between patients with hepatorenal syndrome and other groups. Using ADC_high no significant difference between different groups was noted. RI and PI of both interlobar and arcuate arteries were significantly higher in all the patient groups than the control group (P < 0.0001). RI and PI of both interlobar and arcuate arteries were significantly higher in patients with hepatorenal syndrome.

Conclusion

Liver cirrhosis, even in the presence of refractory ascites, did not affect the ADC value of renal parenchyma, however ADC value is affected in renal parenchyma of patients with hepato-renal syndrome. Duplex-Doppler ultrasound of intrarenal arteries enables the early detection of renal hemodynamic disturbances in patients with liver cirrhosis.     

The Usefulness of Pulsatile Flow Detection in Measuring Resistive Index in Renal Doppler US

Objective

To assess the usefulness of pulsatile flow detection (PFD), a newly developed function of color Doppler US, in measuring resistive index (RI) in renal Doppler US and to compare it with conventional color Doppler (CCD).

Materials and Methods

Fifty-six kidneys in 31 patients were randomly selected and divided into two groups. In group A, RI was measured first with the aid of CCD, and then with PFD. In group B, data were obtained in the reverse order. The time required for each RI measurement was recorded in seconds. The quality of the Doppler spectral waveform was subjectively graded as 0, 1, or 2 and examination time and waveform quality were compared between PFD and CCD.

Results

The time required to measure RI with PFD (PFD time) was less than with CCD (CCD time) (mean 42.7 secs vs. mean 70.3 secs; p = 0.031). There was no significant difference in PFD time between group A and B, but CCD time was shorter in group B (70.3 secs vs. 24.6 secs; p = 0.0004). Spectral waveform quality was not significantly different between PFD and CCD.

Conclusion

The time required to measure RI in kidneys can be shortened with the aid of the PFD function in color Doppler US without affecting the quality of the examination.     

Renal Doppler indices and their correlation with laboratory indices of human immunodeficiency virus sero-positive adult individuals

IntroductionRenal Doppler resistive index (RI) and pulsatility index (PI) values are potentially more sensitive at detecting renal abnormalities when compared to standard laboratory indices in patients with HIV/AIDS. To the best of our knowledge, there are no published research articles on renal Doppler indices and their correlation with laboratory indices of HIV sero-positive adult individuals. This study aimed to assess the renal function of HIV-sero-positive adults using RI and PI, and correlating these indices against laboratory values.MethodsA prospective cross-sectional study was conducted from July 2019 to April 2020. A purposive sampling method was employed and included 396 HIV sero-positive adult individuals. Sampling for the renal RI and PI was performed at the level of the inter-lober arteries, in between the medullary pyramids. An RI value above 0.70 and a PI value above 1.56 were consider abnormal. Serum creatine and urea together with evidence of proteinuria were recorded at the time of scanning.ResultsForty-three (10.9%) men had an abnormal RI, 32 (8.1%) had abnormal PI, five (2.5%) had abnormal creatinine, two (1%) abnormal urea and eight (4.1%) with proteinuria. In women, 29 (7.3%) had abnormal RI, 22 (5.6%) abnormal PI, four (2%) abnormal creatinine and urea and six (3%) had proteinuria. There was a statistically significant weak positive correlation between RI and PI and serum creatinine and urea (r > 0.2, P < 0.05).ConclusionThe proportion of patients with abnormal RI and PI was higher than the proportion of participants with abnormal serum urea, creatinine and proteinuria. Renal Doppler indices could be used be used in the early assessment of renal function in HIV sero-positive adults individuals.Implications for practiceSerum creatinine and urea are routinely used to evaluate renal function in patients with HIV/AIDS. Findings from this initial study show that RI and PI could be used detecting early renal abnormalities when compared to standard laboratory values.     

The distinction between acute renal transplant rejection and cyclosporine nephrotoxicity: value of duplex sonography

Although sonography is useful in the evaluation of renal transplants, there are no objective sonographic findings for reliably differentiating acute rejection from cyclosporine nephrotoxicity. This study was undertaken to determine the role of pulsed Doppler flow analysis (duplex sonography) in making this distinction. Duplex Doppler sonography was performed in 106 patients with normally functioning transplanted kidneys and in 34 patients with renal transplant dysfunction who underwent percutaneous biopsy. Renal vascular impedance was estimated in the segmental, interlobar, and arcuate arteries by calculating the ratio of end-diastolic minimum velocity to systolic peak velocity (diastolic/systolic ratio). In the healthy control subject, the diastolic/systolic velocity ratios varied in the different arterial segments, ranging from a mean of 0.23 in the segmental arteries to a mean of 0.32 in the arcuate arteries. Seventeen patients experienced acute rejection: eight of the nine with acute vascular rejection had abnormal Doppler ratios; eight patients with acute cellular rejection had normal ratios. Nine patients with cyclosporine nephrotoxicity all had normal duplex scans. Seven patients with chronic rejection had normal ratios. One patient with hemolytic-uremic syndrome had an abnormal flow pattern. These findings indicate that duplex sonography may be useful in differentiating acute vascular rejection from cyclosporine nephrotoxicity in the transplanted kidney.     

肾血流动力学改变在窒息新生儿肾损伤中的诊断价值

目的 探讨肾血流动力学改变在窒息新生儿肾损伤中的早期诊断价值.资料与方法 根据Apgar评分标准将60例新生儿分成轻、重度窒息组及健康对照组,每组20例.运用彩色多普勒超声检测肾主动脉收缩期峰值速度(Vs)、舒张期末血流速度(Vd)及阻力指数(Rl),并测定血清尿素氮(BUN)、肌酐(Cr)及尿内皮素-1 (ET-1)水平.依据健康对照组设立正常参考值上、下限,高于上限或低于下限视为异常.同时分析各组间指标的变化及相关性.结果 各窒息组Vs、Vd、RI及ET-1异常发生率更高,与健康对照组比较,差异有统计学意义(P＜0.01).各窒息组BUN、Cr异常发生率低,仅重度窒息组与健康对照组比较,差异有统计学意义(P＜0.01).窒息患儿Vs、Vd与BUN、Cr、ET-1之间呈负相关(P＜0.01),RI与BUN、Cr、ET-1之间呈正相关(P＜0.01).结论 窒息新生儿早期肾损伤伴有肾血流动力学改变,且与窒息程度相关,提示肾动脉血流动力学参数可作为判定窒息新生儿早期肾损伤的敏感指标.     

Detection of vascular complications in renal allografts with color Doppler flow imaging

One hundred ninety-five color Doppler flow (CDF) examinations were performed in 146 renal allografts to assess the capabilities of this technique in detecting intra- or extrarenal vascular complications. Conventional angiography was also performed in 44 transplants. In the group of transplants with angiographic correlation, CDF sonography enabled correct identification of 30 of 34 vascular complications. CDF showed 10 of 11 significant stenoses of the renal artery or of one of its main branches. There were two false-positive renal artery stenoses (one normal artery and one 40% stenosis). Nine of nine renal artery thromboses and the single pseudoaneurysm were also identified. Within the parenchyma, CDF sonography demonstrated five of five segmental infarcts, two of two postbiopsy arteriovenous fistulas, and three of six segmental or interlobar artery stenoses. Measurement of peak systolic velocity showed a significant difference (P less than .05) between a group (n = 8) with significant stenosis of the renal artery or one of its main branches (mean, 215.2 cm/sec +/- 32) and a group (n = 14) without stenosis (mean, 99.2 cm/sec +/- 19).     

彩色多普勒血流显像(CDFI)评价胎儿生长发育状况

目的阐明CDFI对评价胎儿宫内状况的可行性。方法200例经普通B超检查的胎儿,按测量各项常规指标的数值分为正常组100例和异常组100例,再分析经CDFI检查,所测定的指标包括胎儿大脑中动脉、肾动脉、胎盘床动脉、脐动脉血流搏动指数(PI)、阻力指数(RI)及脐动脉的收缩与舒张期峰值速率之比(S/D)。对其结果做详细记录,并进行统计学分析。结果正常组100例,经CDFI检查亦正常;胎儿出生时体重在2500g以上,新生儿发育正常。另100例异常组经CDFI检查各项指标中,54例正常,46例异常;胎儿出生时体重均小于2500g,其中54例新生儿虽体重较正常儿偏小,但发育正常;另46例胎儿宫内窘迫,导致导常分娩、新生儿生存率低。结论彩色多普勒血流显像对了解胎儿宫内情况有着重要的作用,是产科检查监护中不可缺少的部分。     

Age dependency of the renal resistive index in healthy children.

It has recently been suggested that the resistive index (RI) in native kidneys of healthy children is age dependent; however, this relationship has not been completely defined or explained. In 110 kidneys in 71 healthy children aged newborn to 11 years, RIs were determined from peripheral sites (presumed to be arcuate, cortical, or distal interlobar arteries). The authors found the normal renal RI (the mean RI in each kidney) to be age dependent. The renal RI in children is commonly elevated above the upper normal limit in adults (0.70) in the 1st year of life, and the overall trend shows a decrease with age. From 4 years on, the likelihood is low (2% probability) that the RI is above 0.70. Variability of the renal RI from individual to individual was most marked in the first 6 months of life, with 51% (19 of 37) of these kidneys having an RI that would be considered abnormal by adult standards. It is concluded that the normal renal RI is age dependent, with an overall decreasing trend with increasing age. This age dependency of the renal RI and, hence, of the renal vascular resistance might be dependent on levels of active renin, as the maturational profile of the renal RI more closely parallels that of active renin than those of other renal functional parameters.     

彩色多普勒血流显像对恶性滋养细胞血流的测定

目的 本文动态观察２６例恶性滋养细胞肿瘤的彩色多普勒血流显像的表现,旨在研究彩色多普勒血流显像在恶性滋养细胞肿瘤诊断和治疗中的应用价值。结果 患者肿瘤区内部及周边可见丰富的彩色血流信号,经多普勒取样后,可见异常血流信号,其阻力指数（ＲＩ〈０．５）明显低于子宫动脉。未经治疗患者的子宫动脉与临床已痊愈相比,其最大收缩期速度（ＰＳ）了小舒张末期速度（ＥＤ）明显增高而ＲＩ明显降低,均具有统计学差异,故子宫     

Renal changes from extracorporeal shock-wave lithotripsy: evaluation using Doppler sonography

In this study, duplex Doppler sonography was used to evaluate flow changes within renal intraparenchymal vessels induced by extracorporeal shock-wave lithotripsy (ESWL). We have examined 20 patients with caliceal stones before, 1 h and 24 h after ESWL. Doppler waveforms were obtained both from arteries located near the stone and at least at 3 cm from it, and resistive index (RI) measured. A statistically significant increase of the RI (0.079 ± 0.039 mean increase; P < 0.001) was detected 1 h after ESWL in vessels located near the stone. After 24 h, RI tended to normalize (0.056 ± 0.037 mean decrease; P < 0.001). The residual difference (0.022 ± 0.043; P = 0.399) between mean RI values obtained near the stone before and 24 h after ESWL was mainly due to persistent elevated RI values in three patients with ESWL induced hydronephrosis. No significant RI changes were recognized in intraparenchymal vessels located far from the stone. In all patients, Doppler alterations were not associated with morphologic changes of renal parenchyma. Correspondence to: L. E. Derchi     

Duplex doppler ultrasound in determination of renal artery stenosis

Twenty-six cases of renal artery stenosis were evaluated with Doppler ultrasound using the pulsatile flow index (PFI). To establish normal values, the PFI in 60 renal arteries in 30 healthy volunteers was obtained. Normal values by PFI ranged between 0.48 and 0.71 (mean ± SD: 0.6 ± 0.06). In renal artery stenosis the PFI range was 0.72–0.79. The normal upper limit was 0.71. The PFI failed in three patients; however, an ultrasound examination showed secondary renal disease (two patients with stenosis on both sides with a shrunken kidney on one side, and one patient with hypernephroma on the opposite side). The PFI was normal (14 of 14 patients) in patients without angiographic evidence of stenosis or after successful dilatation.     

Utility of color duplex sonography in the assessment of efficacy of the stellate ganglion blockade

Purpose: 
To assess the hemodynamic changes in the upper extremity arteries after sympathetic ganglion blockade (SGB) by using spectral Doppler parameters and to determine the applicability of these parameters for the evaluation of SGB efficacy. Material and Methods: 
Spectral Doppler parameters (peak systolic velocity (PSV), end diastolic velocity (EDV), mean velocity (mean V), flow volume, resistive and pulsatility indices (RI, PI), inner arterial diameters (intima to intima) (D) with simultaneous recordings of heart rate (HR), systolic and diastolic blood pressures and upper extremity surface temperature changes) were recorded before and 5 min after during the first, fifth and tenth SGB procedures. Results: 
SGB induced an increase in skin temperature in the ipsilateral hand and persistent dilatation of the radial diameter accompanied by reduction of RI and PI in the radial and third digital arteries in all patients. Conclusion: 
Hemodynamic changes assessed by spectral Doppler parameters could be used as sensitive and objective measurements of peripheral sympathetic nervous activity and vascular tonus, and may confirm a successfully performed SGB.     

Perivascular color artifact: pathologic significance and appearance on color Doppler US images

A distinctive type of artifactual extravascular assignment of color was identified in 49 color Doppler ultrasound (US) examinations in 43 patients. This artifact appeared as a random localized mixture of red and blue assigned to perivascular soft tissues; the artifact varied with the cardiac cycle, being most prominent in systole and absent or less prominent in diastole. The artifact was seen in 26 patients (32 examinations) at an anastomotic site or stenotic lesion associated with surgically created arteriovenous fistulas for hemodialysis. It was also observed in ten patients with accidental iatrogenic arteriovenous fistulas (renal transplant [n = 6], femoral artery [n = 3], and iliac artery [n = 1]), five with stenotic arteries not associated with arteriovenous fistulas, and two with arterial aneurysms. The authors believe this artifact reflects perivascular tissue vibration caused by turbulent intravascular blood flow. If properly recognized and accurately interpreted, the artifact can be a valuable color Doppler US sign of underlying vascular abnormality.     

Color-coded duplex sonography of dysfunctional kidney transplants. Correlation of the resistive index with the histopathologic results of biopsy

The resistive index (RI) is used as a measure of the vascular resistance in renal allografts. The sample volume for the measurement can be positioned much more exactly with color duplex US than with duplex US, resulting in more precise values for the RI. To find out which pathologic changes lead to an increase of the RI, we correlated the RI with the histopathological results obtained in 43 biopsies. Our results show that it is not possible to differentiate between vascular and interstitial rejection on the basis of the RI because there is no statistically significant difference between the RI values caused by the two types of rejection. Distinct interstitial infiltration, edema of any origin, vascular changes and also chronic rejection and arteriolosclerosis lead to elevated RI. A good correlation was found between the elevation of RI and the severity of the vascular changes. Severe tubular and glomerular changes, cyclosporine toxicity, tubular necrosis, cytomegaly infection, glomerulonephritis and dysfunctions of other causes did not lead to elevation of the RI.     

彩色多普勒超声对治疗移植肾急性排斥反应的监测价值

目的探讨彩色多普勒超声在移植肾急性排斥反应治疗过程中的监测价值。方法回顾性分析41例急性排斥的移植肾患者治疗前后不同时间点彩色多普勒超声特点及血肌酐水平,对比不同时间点移植肾叶间动脉RI及血肌酐水平的差异,分析治疗前叶间动脉RI与治疗后1个月血肌酐水平的相关性。结果移植肾急性排斥反应发生时及逆转后声像图表现及彩色多普勒超声测值存在差异,治疗后第3天开始彩色多普勒超声图像及血流参数变化与治疗前对比差异有统计学意义（P〈0．05）,治疗后第5天开始血肌酐与治疗前对比差异有统计学意义（P〈O．05）,治疗前叶间动脉RI与治疗效果具有较好的相关性。结论彩色多普勒超声可用于移植肾急性排斥反应的诊断及治疗效果评估,发生移植肾急性排斥反应时,彩色多普勒超声图像及血流参数变化早于血肌酐变化,治疗前叶间动脉RI与治疗效果具有很好的相关性。