Diagnosis Of Renal Artery Stenosis Research Articles

Unenhanced respiratory-navigated NATIVE® TrueFISP magnetic resonance angiography in the evaluation of renal arteries: Comparison with contrast-enhanced magnetic resonance angiography.

To compare unenhanced three-dimensional (3D) NATIVE® true fast imaging with steady-state precession (TrueFISP) magnetic resonance (MR) angiography with the more conventional MR angiography technique obtained after intravenous administration of a gadolinium chelate in the evaluation of renal arteries and their branches in patients with suspected renal artery stenosis. A total of 39patients (25men, 14women) with a mean age of 51.4±17.5years (SD) (range: 10-82years) were included in the study. All patients with suspected renal artery stenosis underwent unenhanced 3D NATIVE® TrueFISP MR angiography and contrast-enhanced MR angiography. The two MR angiography methods were compared by two independent readers for image quality using a four-point scale, diagnostic performance and grading of renal artery stenosis on a total of 78renal arteries. For both readers image quality of unenhanced 3D NATIVE® TrueFISP MR angiography (3.12 to 3.63) was greater than that of contrast-enhanced MR angiography (1.94 to 2.71) for renal artery ostium-trunk and the left renal artery segmental branches. The sensitivity of 3D NATIVE® TrueFISP MR angiography for the diagnosis of renal artery stenosis was 100% for both readers for the right renal artery and 66% and 80% for the left renal artery for reader 1 and reader 2, respectively. Agreement between 3D NATIVE® TrueFISP MR angiography and CE-MR angiography was 95% (74/78) for reader 1 and 92% (72/78) for reader 2. Unenhanced NATIVE® TrueFISP magnetic resonance angiography can play an additional role in the evaluation of renal arteries in patients with hypertension, especially in subjects at risk of nephrogenic systemic fibrosis.

Duplex ultrasound for identifying renal artery stenosis: direct criteria re-evaluated.

Background Renal artery duplex ultrasound (RADUS) is an established method for diagnosis of renal artery stenosis (RAS), but there is no consensus regarding optimal RADUS criteria. Purpose To define optimal cutoff values for RADUS parameters when screening for RAS using intra-arterial trans-stenotic pressure gradient measurement (PGM) as reference. Material and Methods The renal arteries of 58 consecutive patients evaluated for renovascular hypertension were examined by RADUS and PGM. Conclusive measurements with both methods were obtained in 76 arteries. Hemodynamically significant RAS was defined as PGM ≥15 mmHg and was found in 43 of the 76 arteries. RADUS parameters included renal artery peak systolic velocity (PSV) and the renal-aortic ratio (RAR) of flow velocities. Receiver operating characteristic curves (ROCs) and Youden's index were used to calculate optimal RADUS criteria for RAS. Results When traditional RADUS criteria for RAS were used, with a combination of PSV ≥180 cm/s and RAR ≥3.5, the sensitivity was 62% and the specificity was 91%. When RADUS criteria were optimized for sensitivity, then RAR ≥2.6 alone resulted in a sensitivity of 89% and a specificity of 69%. Conclusion The RAR ≥2.6 is a more sensitive criterion than traditional RADUS criteria when screening patients with clinical suspicion of RAS.

Successful angioplasty during pregnancy for renal artery stenosis

Renal artery stenosis can be diagnosed during pregnancy and treated at the same time. A 30-year-old woman had a sudden, severe but asymptomatic hypertensive crisis at 21 weeks of gestation. The diagnosis of renal artery stenosis suspected on Doppler ultrasonography was confirmed and treated by renal angioplasty, which reduced her blood pressure. At 27 weeks of gestation, her blood pressure increased again, associated with significant proteinuria, suggesting pre-eclampsia. A cesarean section was performed giving birth to a healthy 940-g child. Renal artery stenosis should be considered when sudden and early-onset hypertension appears during pregnancy.

Imaging in Chronic Kidney Disease.

Chronic kidney disease (CKD) diagnosis and staging are based on estimated or calculated glomerular filtration rate (GFR), urinalysis and kidney structure at renal imaging techniques. Ultrasound (US) has a key role in evaluating both morphological changes (by means of B-Mode) and patterns of vascularization (by means of color-Doppler and contrast-enhanced US), thus contributing to CKD diagnosis and to the follow-up of its progression. In CKD, conventional US allows measuring longitudinal diameter and cortical thickness and evaluating renal echogenicity and urinary tract status. Maximum renal length is usually considered a morphological marker of CKD, as it decreases contemporarily to GFR, and should be systematically recorded in US reports. More recently, it has been found to be a significant correlation of both renal longitudinal diameter and cortical thickness with renal function. Conventional US should be integrated by color Doppler, which shows parenchymal perfusion and patency of veins and arteries, and by spectral Doppler, which is crucial for the diagnosis of renal artery stenosis and provides important information about intrarenal microcirculation. Different values of renal resistive indexes (RIs) have been associated with different primary diseases, as they reflect vascular compliance. Since RIs significantly correlate with renal function, they have been proposed to be independent risk factors for CKD progression, besides proteinuria, low GFR and arterial hypertension. Despite several new applications, US and color Doppler contribute to a definite diagnosis in <50% of cases of CKD, because of the lack of specific US patterns, especially in cases of advanced CKD. However, US is useful to evaluate CKD progression and to screen patients at risk for CKD. The indications and the recommended frequency of color Doppler US could differ in each case and the follow-up should be tailored.

Ultrasound diagnostics of renal artery stenosis: Stenosis criteria, CEUS and recurrent in-stent stenosis.

Background and purposeAs a non-invasive, side effect-free and cost-effective method, ultrasonography represents the method of choice for the diagnosis of renal artery stenosis. Four different criteria in total, including two direct criteria in peak systolic velocity (PSV) and renal aortic ratio (RAR) and two indirect criteria in resistance index (RI) and acceleration time (AT) for the measurement of relevant renal artery stenosis are described, each demonstrating highly variable accuracy in studies. Furthermore, there is controversy over the degree beyond which stenosis becomes therapeutically relevant and which ultrasound PSV is diagnostically relevant in terms of stenosis grading.Material and methodsThis article gives a critical review based on a selective literature search on measurement methodology and the validity of ultrasound in renal artery stenosis. A critical evaluation of methods and a presentation of measurement principles to establish the most precise measurement method possible compared with the gold standard angiography, as well as an evaluation of the importance of computed tomography angiography (CTA) and magnetic resonance angiography (MRA).Results and conclusionsThe PSV provides high sensitivity and specificity as a direct measurement method in stenosis detection and grading. Most studies found sensitivities and specificities of 85–90 % for > 50 % stenosis at a PSV > 180–200 cm/s in ROC curve analysis. Other methods, such as the ratio of the PSV in the aorta to the PSV in the renal artery (RAR) or indirect criteria, such as side to side differences in RI (dRI) or AT can be additionally used to improve accuracy. Contrast-enhanced ultrasound improves accuracy by means of echo contrast enhancement. Although in the past only high-grade stenosis was considered relevant for treatment, a drop in pressure of > 20 mmHg in > 50 % stenosis (PSV 180 cm/s) is classified as relevant for increased renin secretion. Stenosis in fibromuscular dysplasia can be reliably graded according to the continuity equation. Although the available studies on the grading of in-stent restenosis are the subject of controversy, there is a tendency to assume higher cut-off values for PSV and RAR. Whilst MRA and CTA demonstrate an accuracy of > 90 %, this is at the cost of possible side effects for patients, particularly in the case of pre-existing renal parenchymal damage.Additional online materialThis article includes two additional video sequences on visualizing renal artery stenosis. This supplemental material can be found under: dx.doi.org/10.1007/s00772-015-0060-3

Value of linear array ultrasonic with high-frequency in the diagnosis of renal artery stenosis

Objective To evaluate the value of linear array ultrasonic with high-frequency in the diagnosis of renal artery stenosis(RAS). Methods 1 828 patients who were doubted with RAS were studied. All of them were checked by ultrasonic with convex array probe and linear array probe. Results The sensitivity, specificity, false positive rate, false negative rate of convex array probe were 8.20%,97.10%,2.90%,21.80%. The sensitivity, specificity, false positive rate, false negative rate of linear array probe were 91.13%, 99.80%, 0.20%, 8.87%. Conclusion Linear array with high- frequency can keep the measurement angle less than 60°, and can show the plaque, nature of the plaque and narrow rate of renal artery. It may be more helpful in the diagnosis of RAS. Key words: Ultrasonography; Renal Artery Obstruction

Comparison of Catether Angiography with Magnetic Resonance Angiography in the Diagnosis of Renal Artery Stenosis

Comparison of Catether Angiography with Magnetic Resonance Angiography in the Diagnosis of Renal Artery Stenosis

Co-Existence of Carotid Artery Disease, Renal Artery Stenosis, and Lower Extremity Peripheral Arterial Disease in Patients With Coronary Artery Disease

In atherosclerosis, carotid artery stenosis (CAS), renal artery stenosis (RAS), lower extremity peripheral arterial disease (PAD), and coronary artery disease (CAD) are common pathologic lesions; their interrelationship is, however, unclear. We studied concomitant multiple atherosclerotic lesions in patients with CAD to understand their prevalence and relations. A cross-sectional analysis was performed on data from consecutive patients who underwent nonemergent coronary angiography. Simultaneous carotid and renal artery Doppler studies and ankle-brachial systolic pressure measurements were reviewed to diagnose concomitant lesions and their severity. The study included 1,734 patients (aged 71 ± 9 years; 70% men), with prevalences of CAS, RAS, lower extremity PAD, and CAD of 6%, 7%, 13%, and 72%, respectively. In patients with CAD (n = 1,253), the prevalences of CAS, RAS, and lower extremity PAD were 7%, 9%, and 16%, respectively; 24% CAD patients had ≥1 additional atherosclerotic lesion. Significant interactions among the prevalences of these lesions were found. In addition, the extent of CAD and the prevalences of CAS, RAS, and lower extremity PAD were significantly correlated. Multivariate analysis supported these relationships. In conclusion, the prevalences of CAS, RAS, lower extremity PAD, and CAD were strongly interrelated in the study population; CAD severity was related to that of other atherosclerotic lesions. Additional systematic screening of other concomitant atherosclerotic lesions is recommended, especially in CAD patients having multivessel disease, left main disease, and/or already diagnosed with other concomitant atherosclerotic lesions.

Renal Doppler evaluation in the child with hypertension: a reasonable screening discriminator?

Hypertension is diagnosed in 1-5% of children, and 5-10% of those hypertensive children have renovascular disease. The gold standard for a diagnosis of renal artery stenosis is arteriography, and Doppler ultrasound (Doppler US) continues to be advocated as a useful screening test. The purpose of this study was to determine the utility of Doppler US in children as a screening tool and to better define clinical features of children in whom arteriography should be performed. This retrospective study evaluated the imaging and clinical parameters for all children who had a renal US with Doppler followed by a diagnostic arteriogram for the evaluation of hypertension during a 12-year period at a tertiary children's hospital. Sixty-two children were included. We evaluated each child's clinical parameters and placed each child into one of three categories of hypertension: mild, moderate or severe. Eleven of 17 kidneys with proven renal artery stenosis were detected with Doppler US (sensitivity 64%). Six children with renal artery stenosis were missed by Doppler US, four of whom had segmental artery lesions. Of the children with positive renal artery stenosis on arteriography, all but three (79%) were classified as having moderate to severe hypertension. Doppler US is a useful screening examination when evaluating children with hypertension, detecting renal artery stenosis in most affected children. The clinical risk classifications are helpful in guiding which children should proceed with arteriography regardless of the Doppler US results.

Intrarenal Color Doppler Ultrasonography in the Diagnosis of Accessory Renal Artery Stenosis

Conventional color Doppler ultrasonography of main renal artery is a valuable non invasive tool in screening and diagnosing patients with renal artery stenosis. However, this technique suffer a set back from many limitations. Color Doppler ultrasonography examination of intrarenal branch arteries using the parameters like, acceleration time, acceleration time ratio, and acceleration index with additional sampling from upper and lower pole of kidney has shown good results in diagnosis of renal artery stenosis. We successfully diagnosed accessory renal artery stenosis in two patients using intrarenal Doppler technique. We conclude, intra renal Color Doppler ultrasonography with additional sampling from upper and lower pole is most accurate method for diagnosis of significant RAS including accessory RAS. Nepalese Journal of Radiology; Vol. 2; Issue 2; July-Dec. 2012; 59-64 DOI: http://dx.doi.org/10.3126/njr.v2i2.7687

Captopril Renal Scintigraphy in Screening and Diagnosis of Renal Artery Stenosis - A Prospective Study

The present study was carried out to assess the role of Tc99m-DTPA captopril renal scintigraphy in screening and diagnosing of patients with renal artery stenosis. Materials and Methods: A total of 26 hypertensive patients with a clinical suspicion of RAS underwent baseline and captopril scintigraphy using 259-370 MBq (7-10mCi) of Tc99m-DTPA. The captopril scintigraphy was done after oral dose of 50mg of captopril with in three baseline study. DSA was done in all patients irrespective of scintigraphy results due to high clinical suspicion of RAS. Results: Of 26 patients, 18 had renal artery stenosis (10 unilateral, 8 bilateral), making a total of 26 involved RA on DSA. Of these 26 involved RA, 16 were stenosis&gt; 60%, 2 were stenosed&lt; 60% while 8 were completely occluded. Of the sixteen RA with stenosis &gt; 60%, only 12 were detected by captopril scintigraphy (Sensitivity-75%). Eight kidneys with complete occlusion, 6 were non-functioning and 2 were poorly functioning (&lt;20%) on scintigraphy. Among 27 normal RA, (25 normal and two &lt;60% stenosis) only 19 were negative on scintigraphy (specificity-70%). Two kidneys with less than 60% stenosis were positive on scintigraphy. The overall accuracy of captopril DTPA scintiography was found to be 72.1% with PPV and NVP of 66.7% and 82.6% respectively. Two patients with accessory RA were not picked up on captopril scintigraphy. Conclusion: Tc99m-DTPA captopril scintigraphy has average sensitivity and specificity. The effectiveness of captopril scintigraphy in diagnosis of completely occuluded RA, accessory RAS and RAS in poorly functioning kidney is poor, therefore this test cannot be considered as screening test for RVH. Nepalese Journal of Radiology; Vol. 2; Issue 2; July-Dec. 2012; 28-35 DOI: http://dx.doi.org/10.3126/njr.v2i2.7682

Analysis of the sensitivity and specificity of noninvasive imaging tests for the diagnosis of renal artery stenosis.

BackgroundAging and atherosclerosis are related to renovascular hypertension in elderly individuals. Regardless of comorbidities, renal artery stenosis is itself an important cause of cardiovascular morbidity and mortality. ObjectiveTo define the sensitivity, specificity, positive predictive value, and negative predictive value of noninvasive imaging tests used in the diagnosis of renal artery stenosis. MethodsIn a group of 61 patients recruited, 122 arteries were analized, thus permitting the definition of sensitivity, specificity, and the relative contribution of each imaging study performed (Doppler, scintigraphy and computed tomographic angiography in comparison to renal arteriography). ResultsThe mean age was 65.43 years (standard deviation: 8.7). Of the variables related to the study population that were compared to arteriography, two correlated with renal artery stenosis, renal dysfunction and triglycerides. The median glomerular filtration rate was 52.8 mL/min/m2. Doppler showed sensitivity of 82.90%, specificity of 70%, a positive predictive value of 85% and negative predictive value of 66.70%. For tomography, sensitivity was 66.70%, specificity 80%, positive predictive value 87.50% and negative predictive value 55.20%. With these findings, we could identify the imaging tests that best detected stenosis. ConclusionTomography and Doppler showed good quality and efficacy in the diagnosis of renal artery stenosis, with Doppler having the advantage of not requiring the use of contrast medium for the assessment of a disease that is common in diabetics and is associated with renal dysfunction and severe left ventricular dysfunction.

Taking a sound approach to acute kidney injury

Taking a sound approach to acute kidney injury

Impact of Atherosclerosis and Age on Doppler Sonographic Parameters in the Diagnosis of Renal Artery Stenosis

The purpose of this study was to investigate the influence of atherosclerosis and age on 4 representative Doppler parameters in the diagnosis of renal artery stenosis. The 4 parameters, renal peak systolic velocity (PSV), renal-aortic ratio, renal-interlobar ratio, and acceleration time, were measured in 208 patients before angiography. The 208 patients were divided into groups according to age and atherosclerosis stratification. The Student t test, 1-way analysis of variance, and the χ(2) test were used to compare all 4 parameters and clinical characteristics. The optimal cutoff values were determined by receiver operating characteristic curves. The diagnostic concordance between atherosclerosis and age strata was evaluated by the Cohen κ coefficient. Of the 416 renal arteries shown on Doppler sonography, 204 had a diagnosis of renal artery stenosis and 19 as occlusion on angiography. The optimal cutoff values for the renal-aortic ratio and renal-interlobar ratio in the groups aged 46 years or older and younger than 46 years were much different (2.3 versus 1.4 and 5.1 versus 6.5, respectively), whereas those for the renal PSV and acceleration time were close to each other or the same (170 versus 180 cm/s and 51 versus 51 milliseconds). The κ coefficients for the renal PSV, renal-interlobar ratio, acceleration time, and renal-aortic ratio between the atherosclerosis and age strata were 0.93, 0.99, 1.00, and 0.71. Atherosclerosis and age show comparable influences on Doppler parameters in the diagnosis of renal artery stenosis. For clinical convenience, cutoff values may be separately established on the basis of a 46-year-old borderline for the renal-aortic ratio and renal-interlobar ratio, although this process is not necessary for the renal PSV and acceleration time.

Research of multiarterial atherosclerotic disease in hypertensive patients with renal artery stenosis

The detection of the renal artery stenosis in hypertensive patients can be a signal of systemic arterial atherosclerosis. To identify and characterize clinical-epidemiologically the hypertensive patients with renal artery stenosis, evaluating factors of cardiovascular risk and presence of symptomatic multiarterial atherosclerotic. Were selected the hypertensive patients who were assisted at the Nephrological Clinic of Universidade Federal do Triângulo Mineiro (UFTM) between 2000-2010, with diagnosis of renal artery stenosis of atherosclerotic etiology. Epidemiological data were evaluated (gender, age, ethnicity), factors of cardiovascular risk (diabetes, hypercholesterolemia, hypertriglyceridemia, tabagism, metabolic syndrome), information on hypertension (time of diagnosis, family report, number of used medicines), previous cardiovascular events (acute myocardial infarctation, ischemic stroke, peripheral arterial disease). Blood pressure levels, global cardiovascular risk and Score Framingham were stratified. Casuistry of 30 patients, feminine majority (73.3%), average of 66 year-old age, 86.67% white, medium time of hypertension of 19.94 years, 89.92 without family report, 13.8 with diabetes, 65.51% smoking, 17.25% hypertriglyredemia, 62.06% with hypercholesterolemia and 66.7% with metabolic syndrome. Average number of medicines in use: 3.26. Dominant right-sided renal artery stenosis separately (46.7%) and in proximal third (56.7%). High creatinine levels in 40% of the patients. As for the hypertension phase, majority phase 2 (47%) and 73.3% with high global cardiovascular risk. Average Framingham Score of 13%. 66.7% presented atherosclerotic disease in another place, being infarctation the main one (53.3%). The most common correlation was with acute myocardial infarctation, what implicates in the search of the coronary compromising to the diagnosis of renal artery stenosis in hypertensive patients to try avoid future damages to the patient.

The incidence of renal artery stenosis in the patients referred for coronary artery bypass grafting

Multivessel coronary disease or peripheral arterial disease is the clinical clue to diagnosis of renal artery stenosis (RAS). RAS is considered equivalent to coronary artery disease in terms of cardiovascular risk. In this study, we evaluated the incidence of RAS in the patients who were proposed to undergo coronary artery bypass grafting (CABG). Diagnostic evaluations of coronary arteriography and renal artery angiography were performed during the same procedure; the patients who were proposed for CABG in terms of CAD anatomy and clinical manifestation were enrolled. RAS was evaluated and a diameter stenosis of ≥50% was considered as significant RAS; significant RAS patients were divided into five groups. The five groups of RAS were as follows: (1) unilateral RAS ≥50–70%, (2) unilateral RAS ≥70%, (3) bilateral RAS ≥50–70%, (4) one-renal-artery stenosis ≥50–70%, contralateral RAS ≥70%, and (5) bilateral renal artery stenosis ≥70%. A total of 151 patients were enrolled, and RAS (≥50% stenosis in either or both renal arteries) was identified in 47.02% (71/151) patients. Unilateral RAS ≥50–70% was identified in 16.6% (25/151) patients, unilateral RAS ≥70% in 4.6% (7/151) patients, bilateral RAS ≥50–70% in 7.9% (12/151) patients, one-renal-artery stenosis ≥50–70% and contralateral RAS ≥70% in 7.9% (12/151) patients, and bilateral RAS ≥70% was in 9.9%(15/151) patients. The incidence of RAS was 29.03% (18/62) in patients aged ≤60 years, 60% (36/60) in patients aged >60 and ≤70 years, and 58.62% (17/29) in patients aged >70 years. The incidence of RAS was significantly higher in patients aged >60 - ≤70, and >70 years than patients aged ≤60 years (P = 0.001 and P = 0.007, respectively). There was a trend that the incidence of RAS in patients with hypertension [HTN, 50.40% (64/127)] was higher than those without HTN (29.17%, 7/24), with P = 0.056. The incidence of RAS was 47.02% in patients who were proposed for CABG; bilateral RAS of ≥70% was 9.9%. Older age and HTN were associated with RAS in patients who were referred for CABG. This study indicates that the incidence of RAS was high in the patients referred for CABG, and the renal function should be taken care of.

The value of SPECT in diagnosis of renal artery stenosis

The value of SPECT in diagnosis of renal artery stenosis

The value of glomerular filtration rate for diagnosis of renal artery stenosis

The value of glomerular filtration rate for diagnosis of renal artery stenosis

Diagnosis of renal arterial stenosis and quantification of the degree of stenosis: multidetector computed tomography angiography versus digital subtraction angiography

Background: We determined the diagnostic value of multidetector computed tomography angiography (MDCTA) for detection and gradation of renal arterial stenosis (RAS). Methods: Seventy-eight patients (53 males, 25 females; mean age 60.8±14.9 years; range 18 to 86 years) who suffered from hypertension and were found to have RAS on MDCTA or who were found suitable for endovascular treatment of an abdominal aortic aneurysm during the evaluation with MDCTA underwent digital subtraction angiographic (DSA) examinations. The MDCTA findings were compared with the DSA findings. Statistical analysis of data was performed to detect renal arterial stenosis and the degree of stenosis based on diameter measurement. The study was carried out prospectively and approved by the hospital institutional review board. Informed consent was obtained from all patients. Results: Seventy-nine of 156 renal arteries were found to have stenosis and six were found to have occlusion while 71 were normal on MDCTA. Seventy of 156 renal arteries were found to have stenosis and six to have occlusion while 80 were normal on DSA. Overall sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy rate were found to be 97.4%, 86.3%, 87.1%, 97.2% and 91.7%, respectively. For determination of the degree of stenosis, the sensitivity was in the range of 74.1-100%, the specificity was in the range of 93.7-100%, the PPV was in the range of 55-100%, the NPV was in the range of 94.5-100%, and the accuracy rate was in the range of 90.4-100%. Conclusion: Multidetector computed tomography angiography can be accepted as a noninvasive and reliable modality for the evaluation of RAS with high sensitivity, specificity, and diagnostic accuracy rates.

Color-coded duplex sonography in the diagnosis of renal artery stenosis—A 3-year experience in a large community hospital

From October 1991 to May 1995 we examined 1018 patients admitted for suspected renal artery stenoses. Of these, 229 consecutive patients (143 males and 86 females) were subjected to angiography. The mean age was 59 years (range 9–79 years). We used an Acuson 128 XP 10 duplex-unit with a 2/2.5-MHz sector probe. Color-coded tracings, pulsed-mode and continuous-mode Doppler readings were taken from the intra- and extrarenal arteries in order to define the velocity of the blood, to find spectral disturbances, and to calculate the resistive index (Pourcelot index) from these readings. In 85% of the patients a complete screening of the vessels was possible. The diagnosis of significant renal artery stenosis, i.e., a 60% reduction of diameter, was made when the maximal systolic velocity (Vmax) was above 1.60 m/second. In patients with Vmax between 1.20 and 1.60 m/second the diagnosis of a significant stenosis was made if spectral disturbances were present and a >40% reduced velocity was found elsewhere in the same main renal artery. With these criteria, color-coded duplex sonography (CCDS) in our 229 patients had a sensitivity and specificity of 86% and 96%, respectively. With an 83% prevalence of significant stenoses, the positive predictive value was 96%, the negative predictive value 83%. Forty-eight of the 67 accessory arteries to the kidney could be demonstrated by CCDS. We conclude that CCDS is an excellent screening tool to detect renal artery stenoses in the main renal arteries. Problems arise from stenosed accessory small vessels with hilar or polar destination which can be overlooked with CCDS. CCDS is indispensable for longitudinal follow-up of known renal artery stenoses and for control after angioplasty or operation for renovascular disease.