Comparison of Duplex sonography and color Doppler imaging in renal allograft evaluation: a prospective study

A prospective study compared the diagnostic capability of quantitative Duplex sonography (DS) and color Doppler imaging (CDI) in 49 consecutive patients with 50 renal allografts. Sixty five DS examinations and 65 CDI examinations were performed by two independent investigators on two different machines on the same day. The resistive index (RI) was calculated and the color flow of renal arteries was observed up to the arcuate arteries. There was good correlation of RI values obtained by DS and CDI at all vascular sites. Thirty one allografts were functioning stably and 19 were in a state of dysfunction, defined by histology (n = 17). Forty allografts presented with a RI < 0.9 and normal color flow. All five allografts with a pathologic RI 0.9 showed abnormal color flow (missing flow in arcuate and/or interlobar arteries). Five allografts had a RI < 0.9 but abnormal color flow, possibly due to atrial fibrillation, hypertension, heart failure or a combination of these. A normal color flow pattern excludes severe vascular compromise to the allograft. In addition, CDI revealed three biopsy-related vascular lesions; two of them had been missed by DS.     

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。     

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.     

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。     

Distinction between obstructive and nonobstructive pyelocaliectasis with duplex Doppler sonography

Because animal studies have shown that renal obstruction increases renal vascular resistance, we theorized that obstruction would change the Doppler waveform. We studied the value of the resistive index (RI) calculated from the duplex Doppler waveform to distinguish between obstructive and nonobstructive pyelocaliectasis in 229 kidneys in 133 patients. The RI is the peak systolic frequency shift minus the minimum diastolic frequency shift, then divided by the peak systolic frequency shift. Duplex Doppler sonography was performed prospectively in 70 kidneys with pyelocaliectasis before the presence or absence of obstruction was established. In 54 of 70 kidneys, the presence or absence of obstruction was proved by interventional methods (percutaneous nephrostomy, antegrade or retrograde pyelography, loopography), and in the rest it was proved by body CT, excretory urography, or surgery. Thirty-eight kidneys were found to be obstructed, and 32 had nonobstructive dilatation. In addition, 159 kidneys without pyelocaliectasis were studied to identify possible limitations of Doppler sonography in the diagnosis of obstruction. Clinical history and laboratory data were used to determine that 109 of these kidneys were in normal subjects and 50 were in patients with nondilated renal disease. There was a significant difference between the mean RI of the obstructed (0.77 +/- 0.05) and the nonobstructed dilated (0.63 +/- 0.06) kidneys (p less than .01). Analysis of the receiver-operating-characteristic curve showed an RI of 0.70 to be a good discriminatory level for obstruction, resulting in a sensitivity of 92%, a specificity of 88%, and an accuracy of 90%. All 109 normal kidneys had an RI less than 0.70. Over half (27/50) of the kidneys in patients with nondilated renal disease had an elevated RI (greater than or equal to 0.70). Ninety-six patients had Doppler examinations on both kidneys, and in only six patients did the RI values of each kidney differ by more than 0.10; all six were proved to have unilateral obstruction. Use of duplex Doppler sonography should improve the specificity, and thus the accuracy, of sonography in the noninvasive diagnosis of obstruction and should be used when a dilated collecting system is identified.     

Intrarenal Doppler ultrasound studies in normal and acutely obstructed kidneys.

Renal ultrasound examinations and intrarenal arterial Doppler studies were performed on 48 patients with normal renal tracts and 20 patients presenting with acute renal colic resulting from ureteric calculus, 14 of whom had urographic evidence of renal obstruction. The mean resistance index (RI) of the Doppler waveforms obtained on the 14 obstructed kidneys (70.4 +/- 6.22) was significantly higher than the mean RI of the 96 normal kidneys (62.4 +/- 6.43). The mean difference between the RIs of the obstructed kidneys and their contralateral non-obstructed kidneys (8.37 +/- 4.43) was also significantly higher than the differences in RI seen between pairs of normal kidneys (2.70 +/- 1.71). Five out of 14 obstructed kidneys showed no pelvicalyceal dilatation and could not have been shown to be obstructed on conventional sonography. Four of these five had RI changes suggestive of obstruction and thus 13 of 14 obstructed kidneys would have been identified as obstructed by a combination of Doppler and conventional sonographic findings. 10 of the 14 obstructed kidneys were re-examined after passage of a urinary calculus and nine showed a reduction in the RI of the previously obstructed kidneys. The 10th subsequently required ureterolithotomy.     

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.     

From donor to recipient. Doppler US, power US and scintigraphy of kidney perfusion before and after transplantation

PURPOSE: To follow kidneys from the donor to the recipient by assessing whether perfusion changes occur by using duplex Doppler US, power Doppler US and scintigraphy. MATERIAL AND METHODS: The prospective study included 12 donors and their corresponding 12 recipients. For each donor, both donor kidneys were evaluated by duplex Doppler US, power Doppler US and scintigraphy 1 day before surgery. The same procedure was carried out on the renal allografts at days 1, 3, 5 and months 1 and 3 post-transplantation. Power Doppler findings were classified according to a grading system of 1 to 4. Resistive indices (RIs) were determined based on interlobar and segmental arterial flow. Peak systolic velocity and RIs of the main renal artery were also measured. A perfusion parameter named the peak-to-plateau ratio was calculated. Statistical analysis was performed using the paired-samples t-test. RESULTS: Intrarenal RI elevation and decreased renal artery peak systolic velocity was observed in normally functioning recipient kidneys. CONCLUSION: Duplex Doppler sonography demonstrated that transplanted kidneys had an increase in intrarenal vascular resistance at 1 month and a decrease in renal artery peak systolic velocity at 3 months post-transplantation. Scintigraphy and power Doppler US did not reveal any statistically significant perfusion change in normally functioning kidneys from donor to recipient.     

Functional evaluation of the urinary tract by color-Doppler ultrasonography (CDU) in 100 patients with renal colic

INTRODUCTION AND OBJECTIVE: To evaluate if the addition of a renal color-Doppler ultrasonography (CDU) in the setting of acute renal colic improves the sensitivity of conventional sonography. MATERIALS AND METHODS: Between July 2002 and June 2003, 100 patients (median 49 years) with renal colic have been evaluated. Within 24 h of the admission, a CDU study of the urinary tract was performed using a sonograph GE Logiq 500 PRO with a multifrequency (3-5 MHz) convex probe. The following parameters were evaluated: ultrasonography (US) of both kidneys, ureters and bladder; resistive index (RI) of the arciform arteries of both kidneys in three different parenchymal areas; ureteric jets in response to hydration. A renal RI>0.70 and/or a 10% difference between the kidneys were considered as diagnostic of obstructive uropathy; an asymmetric and/or reduced ureteric jet from the ureteric orifices was an additional indicator of obstruction. All patients underwent a CT scan both with and without the administration of contrast medium. RESULTS: Enhanced helical CT demonstrated an urinary stone in 90 out of the 100 patients (90%): 29 pyelic, 28 at the pyelo-ureteral junction, 23 lumbo-iliac and 10 juxtavesical stones. Among 90 patients with urolithiasis, the stone was undetectable with US in 11 cases (12.2%); in 8 cases (8.9%) pyelocalicectasis was absent, and in 6 patients (6.6%) a non-obstructive hydronephrosis was present. Median RI in obstructed and non-obstructed kidney was 0.73 (range 0.71-0.87) versus 0.62 (0.50-0.68), respectively; in two, obstructed kidneys RI was <0.70 but greater than 10% compared with normal side. Sensitivity and specificity of US, CDU (RI+ureteric jet), unenhanced helical CT and CDU in association with unenhanced helical CT were 94.8 and 55.5, 98.9 and 90.9, 100 and 100%, respectively. DISCUSSION AND CONCLUSIONS: CDU in patients with renal colic and/or pelvicalicectasis improves the diagnostic accuracy of US in distinguishing between obstructive and non-obstructive dilatation. Combined with unenhanced CT, CDU has a 100% sensitivity and specificity. Moreover, due to the absence of contraindications and side-effects, CDU is indicated for the follow-up of patients after ESWL, pregnant women and children.     

Arteriovenous malformations of the kidneys: diagnosis and follow-up with color Doppler sonography in six patients

We performed color Doppler sonography in six patients with arteriovenous malformations of the kidneys. The diagnosis was established by angiography in all patients. Color Doppler sonograms were obtained at a large Doppler frequency-shift range (55 cm/sec of maximal average flow velocity at zero Doppler angle) to depict high-velocity blood flow in the malformation. In all patients, the malformations were seen as focal areas of flow, portrayed as a mixing of lighter colors. These were reflected by a rapid flow rate and marked tortuosity of the vessels. The sonograms showed a small peripheral malformation that was indistinct on selective renal angiography. However, flow in normal vessels grouped in the hilum obscured lighter-color flow of a small central malformation. In three patients who had total or partial ablation of the malformations with alcohol, follow-up color Doppler sonograms showed that the focal areas of flow, represented as mixing of lighter colors, disappeared or became smaller. This study shows that color Doppler sonography is a useful noninvasive procedure for diagnosing arteriovenous malformations of the kidney.     

Renal carcinoma: duplex Doppler evaluation

Doppler ultrasound has a clearly defined role in the assessment of carotid and peripheral vascular disease. In these situations vessel pathology produces alterations in velocity and volume flow and in the flow-velocity spectrum. Flow in the renal arteries is affected not only by disease of the renal vessels but also by the peripheral resistance to flow within the kidney. Alterations in this peripheral resistance resulting from renal disease are reflected in the Doppler flow spectrum analysis. In 14 patients with renal carcinoma, three different blood flow patterns were observed, reflecting the differing vascularity of the renal tumours. These were compared with blood flow in normal kidneys and in kidneys containing renal cysts. Doppler ultrasound adds further information to the study of renal carcinomas, allowing the prediction of tumour vascularity, and may be useful as a preliminary investigation prior to angiography and embolisation.     

Intrarenal arterial Doppler sonography in patients with nonobstructive renal disease: correlation of resistive index with biopsy findings

The resistive index (RI), calculated from the duplex Doppler waveform, was compared with clinical and laboratory findings and the results of renal biopsy in 41 patients with nonobstructive (medical) renal disease. Kidneys with active disease in the tubulointerstitial compartment had a mean RI of 0.75 +/- 0.07. This was statistically significantly different (p less than .01) from the RI in kidneys with disease limited to the glomeruli (mean RI of 0.58 +/- 0.05). Acute tubular necrosis resulted in an elevated RI (mean RI = 0.78 +/- 0.03) as did vasculitis/vasculopathy (mean RI = 0.82 +/- 0.05). Patients with hypertension, proteinuria, or hematuria did not have kidneys with a significantly higher RI than did patients without these clinical factors. Kidneys found to be abnormally echogenic did not have an RI significantly different from kidneys of normal echogenicity. There was a weak correlation between creatinine level and RI value, reflected by a linear correlation coefficient of 0.34. In patients with normal renal RIs, the mean creatinine level was 1.7 +/- 1.7, whereas in those with abnormal RI values (greater than or equal to 0.70), the mean creatinine level was 3.7 +/- 3.6. We conclude that some forms of nonobstructive renal disease can produce changes in the Doppler waveform detectable by RI measurement. The production of Doppler waveform changes is strongly influenced by the site of the main disease within the kidneys. Active disease within the tubulointerstitial compartment (acute tubular necrosis, interstitial nephritis) or vasculitis/vasculopathy generally resulted in an elevated RI, whereas disease limited to the glomeruli, no matter how severe, did not significantly elevate the RI. Degree of renal dysfunction as indicated by serum creatinine level probably affects the Doppler waveform to some degree, but the relationship is weak.     

Stenosis of the renal artery: assessment of slowed systole in the downstream circulation with Doppler sonography.

Slowing and dampening of systole in the arterial network distal to stenosis is a well-known Doppler sign of severe arterial stenosis. To determine whether this sign is present in boys and girls with such stenosis, intrarenal Doppler curves (acceleration index [AI] and resistive index [RI]) were compared with findings on renal arteriograms in 20 boys and girls; the AI was also measured in 10 boys and girls without renal disease. Statistical analysis of AI and RI measurements was performed. Eleven of 32 renal arteries were normal. The normal AI was 4.0-7.0; in arteries with greater than 75% stenosis, the AI was 0.7-1.7. In five arteries studied after angioplasty, the AI had changed from 0.7-1.5 to 4.0-5.6 at the first posttreatment examination (performed 28 hours to 1 week after angioplasty), and it remained normal during the 3-year follow-up period. In kidneys with stenotic arteries, the RIs were lower (0.43-0.54) than in healthy subjects (0.56-0.63). Regression and correlation coefficients of AI and RI measurements were statistically significant, and discrimination between normal arteries and those with greater than 75% stenosis was excellent.     

Duplex Doppler sonography of renal transplants: lack of sensitivity and specificity in establishing pathologic diagnosis

Recent reports have suggested the value of duplex Doppler sonography in the assessment of renal transplant function. Accurate diagnosis of acute rejection and its distinction from acute tubular necrosis and cyclosporine A toxicity have been claimed. We undertook a combined retrospective and prospective analysis of duplex Doppler examinations performed over a 2-year period to assess the value of such studies in evaluating renal allograft dysfunction. Seventy-seven sonographic examinations were performed on 77 renal transplants. A mean resistive index was calculated from Doppler measurements within main, segmental, and interlobar renal arteries by using the following ratio. peak systolic blood-flow velocity--minimum end-diastolic blood-flow velocity/peak systolic blood-flow velocity Forty-eight Doppler results were correlated with transplant biopsies and 29 with clinical course. Twenty-three episodes of acute allograft rejection were confirmed. When a resistive index of greater than or equal to 0.9 was used to indicate acute rejection, sonography had a sensitivity of only 9% and a specificity of 91% for this diagnosis. In one of eight cases of cyclosporine A toxicity and in three of six examples of acute tubular necrosis, the resistive index was greater than 0.9. In all six instances of chronic rejection, the resistive index was less than 0.84. None of eight patients with evidence of infection had a resistive index greater than 0.9. The resistive index range of 12 normally functioning allografts was 0.57-0.69. Correlation between the resistive index and the severity of arterial and arteriolar changes on biopsy was poor. An increased resistive index of renal transplant blood flow, as measured by duplex Doppler sonography, usually signals pathologic changes in an allograft. However, our data indicate that this test is not as sensitive or specific in identifying the cause of transplant dysfunction as has been suggested previously.     

彩色多普勒超声监测Graves病甲状腺动脉栓塞后血流变化的临床研究

目的 研究彩色多普勒超声在监测甲状腺动脉栓塞治疗Grayes病后甲状腺血流变化，以及对临床疗效的评估作用。方法 31例确诊Graves病的患者行甲状腺动脉栓塞治疗，其中11例用彩色多普勒超声监测治疗前后甲状腺的血流变化，观察指标有甲状腺内部血流信号、甲状腺上动脉舒张期内径、收缩期最大血流速度(Vmax)、舒张期最小血流速度(Vmin)、阻力指数(RI)和甲状腺大小。同时观察临床症状和相关的实验室检查指标的变化情况。结果 Graves病甲状腺动脉栓塞治疗后，甲状腺上动脉舒张期内径、Vmax和Vmin明显降低，甲状腺内部血流明显减少，甲状腺体积缩小。临床症状好转或消失，相关的实验室检查指标恢复正常。结论 彩色多普勒超声可用于评估甲状腺动脉栓塞治疗Grayes病的疗效，是一种较好的无创性动态监测方法。     

Normal and transplanted rat kidneys: diffusion MR imaging at 7 T

PURPOSE: To investigate the feasibility of obtaining reproducible apparent diffusion coefficient (ADC) maps of normal rat kidneys by using respiratory-triggered spin-echo diffusion-weighted magnetic resonance (MR) imaging, to investigate the sensitivity of ADC maps in the evaluation of renal blood flow, and to use this technique to monitor acute graft rejection in transplanted rat kidneys. MATERIALS AND METHODS: Spin-echo diffusion-weighted MR imaging measurements were performed in 20 normal rats and nine rats that had undergone transplantation (six rats had received allografts; three had received isografts) at 7 T. To evaluate the effect of alteration in blood flow and water transport function, angiotensin II was infused in six normal rats and a series of spin-echo diffusion-weighted MR images was obtained at five time points. Transplanted kidneys were monitored by obtaining spin-echo diffusion-weighted MR images and gradient-echo MR images every 2 hours for 8 hours on postoperative day 4. Statistical analysis was performed with repeated-measures multivariate analysis of variance and the paired t test. RESULTS: No significant differences in ADC values were observed between right and left kidneys in all three orthogonal directions; however, a small difference was observed between the cortex and medulla. ADC values in the cephalocaudal and mediolateral directions were higher than those in the anteroposterior direction (P <.01 for all). ADC values in the cortex and medulla decreased significantly (by >35%, P <.01) during angiotensin II-induced reduction in renal blood flow. No significant signal intensity change was observed between native and transplanted kidneys on gradient-echo MR images. Allografts exhibited decreased ADC values (P <.01) and isografts exhibited similar ADC values compared with native kidneys. CONCLUSION: These findings suggest that reproducible renal ADC maps can be obtained in rats by using spin-echo diffusion-weighted MR imaging at 7 T. Spin-echo diffusion-weighted MR imaging may have potential as a noninvasive tool for monitoring early graft rejection after kidney transplantation.     

The role of power Doppler sonography in the prenatal evaluation of fetal renal vasculature.

This study was performed to determine whether power Doppler sonography is superior to color Doppler sonography in the depiction of the normal fetal intrarenal vasculature during pregnancy. Twenty-five fetal kidneys in 22 healthy fetuses between 22 and 40 weeks of gestation (mean 32.6 weeks) were studied with color and power Doppler sonography with a 3.75 MHz transducer. The efficacy of power and color Doppler sonography were compared in assessing fetal renal vasculature. Power Doppler sonography demonstrated diffuse "blush" in almost the entire cortex in 21 of 25 fetal kidneys, whereas it was demonstrated in half of the cortex in the other four kidneys. Color Doppler sonography failed to demonstrate a cortical blush in fetal kidneys. Power Doppler sonography has been shown to be superior to color Doppler sonography in the depiction of normal fetal intrarenal vasculature during pregnancy by demonstrating vascular blood flow better than color Doppler sonography.     

Abdominal aorta: characterisation of blood flow and measurement of its regional distribution by cine magnetic resonance phase-shift velocity mapping

Magnetic resonance phase-shift-induced velocity mapping is a powerful technique for measuring in vivo blood velocity and flow non-invasively. Using this method we examined dimensions, distensibility, blood flow and its regional distribution in the abdominal aorta in 10 normal volunteers. Data were acquired at three levels of the descending aorta. Thirty percent reduction in diastolic cross sectional area was observed in the caudal direction between these levels. Total blood flow (ml/min) in the abdominal aorta at the three sites was 4094 ± 1600, 2339 ± 910 and 1602 ± 549 respectively. Flows in the coeliac trunk, superior mesenteric artery and renal arteries were also calculated. The net flow in the abdominal aorta above the coeliac trunk was persistently forward, while there was considerable backflow (13% of total instantaneous flow) below the renal arteries during early diastole. Magnetic resonance imaging is a non-invasive technique for quantitative assessment of blood flow in the abdominal aorta and its main branches. Correspondence to: M. Amanuma     

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).     

Amplitude coded-colour Doppler sonography in paediatric renal disease

The aim of our study was to assess the ability of amplitude coded-colour Doppler sonography (ACDS) to depict altered perfusion in paediatric renal disease in a prospective study. Colour Doppler sonography (CDS) and ACDS examinations were performed in 180 renal units (90 patients; age range newborn to 16 years) with unilateral or bilateral renal disease (e. g. reflux nephropathy, renal scars, end-stage renal disease, ureteropelvic junction obstruction, urinary tract infection, renal failure, haemolytic uraemic syndrome, nephrotic syndrome, systemic lupus erythematosus (LE), renal biopsy, congenital dysplasia, tumour/infiltration). The ACDS results were compared with scintigraphy or CT as well as to clinical findings. Amplitude colour-coded Doppler sonography accurately demonstrated normal vasculature in 49 of 51 healthy kidneys ( = 96 %); 3 healthy kidneys could not be evaluated due to motion/artefacts. In 39 of 43 kidneys with focally altered perfusion ACDS could be performed and correctly depicted focally impaired vasculature/perfusion in 35 kidneys ( = 89.7 %). Seventy-three of 83 kidneys with diffusely impaired perfusion could be evaluated by ACDS and altered pattern was correctly depicted in 58 kidneys ( = 79.4 %), with an overall percentage of agreement of 87.1 %. Amplitude CDS appears to be useful in infants and children. Compared with CDS it improves visualisation of especially focally impaired vasculature/perfusion and should be considered a valuable adjunct to conventional investigations. Received: 12 June 1999 Revised: 10 December 1999 Accepted: 11 August 2000