Comparison of Duplex Ultrasonography and Magnetic Resonance Imaging in the Detection of Significant Renal Artery Stenosis

Abstract

IntroductionRenovascular hypertension (RVH) is one of the most common causes of secondary arterial hypertension. Renal artery stenosis (RAS) is caused by atherosclerosis in 90 % of the RVH patients and fibromuscular dysplasia is found in the great majority of the remaining cases (10). As the renal revascularization might improve renal function and blood pressure control, the screening for the presence of significant renal artery stenosis (RAS) is recommended in selected patients with arterial hypertension. The main clinical clues suggesting RVH include: early or late onset of hypertension, difficult blood pressure control, coexisting atherosclerotic vascular disease and concomitant renal failure of uncertain aetiology (especially when associated with normal urinary sediment and/or precipitated by angiotensin converting enzyme inhibitors or angiotensin receptor blockers).Non-invasive tests are currently recommended for screening of patients with suspected RVH. However, even the use of the modern and sophisticated imaging techniques such as magnetic resonance imaging or computed tomography did not yield unequivocal results in the accurate assessment of renal arteries. While several smaller studies suggest high accuracy of MRA in the detection of RAS (8, 13), largest performed multicentre trial did not confirm these findings (14). Therefore, the intraarterial digital subtraction angiography (DSA) still remains the golden standard for the detection of RAS (9).In order to determine the clinical value of non-invasive approach in the screening for the significant renal artery stenosis in our centre, we decided to compare duplex ultrasonography (DUS) and magnetic resonance angiography (MRA) in patients with clinically high suspicion of RVH. While DUS was chosen because of low cost and wide availability, MRA did not expose the patients to the ionising radiation and offered decreased nephrotoxicity as well as risk of allergic reaction in comparison to computed tomography angiography or DSA. MethodsThe study included the patients with highly suspected RVH (1, 4) who required imaging of renal arteries. The imaging of renal arterial supply was performed by DUS, MRA and DSA in regard to the detection of significant renal artery stenosis and identification of abnormal anatomy of renal arteries. All the exams were done on daily clinical Summary: Objective: The aim of our study was to evaluate duplex ultrasonography (DUS) and magnetic resonance angiography (MRA) in detection of haemodynamically significant renal artery stenosis (RAS). Methods: The study included patients with high clinical suspicion of renovascular hypertension (RVH). The imaging of renal arteries was performed by DUS, MRA and digital subtraction angiography (DSA). Significant RAS was defined as maximum systolic velocity ≥ 180 cm/sec (DUS) or as 60% reduction of the endoluminal arterial diameter (MRA, DSA). The results of DUS and MRA were assessed in respect to the results of DSA. Results: Arterial supply of 186 kidneys in 94 patients was evaluated. DSA revealed...

The value of portable renal hilar Doppler ultrasound screening (RHDUS) for renal artery stenosis in critically-ill patients

“…This is comparable to success in other studies of renal Doppler ranging from 86% to 94% [5,7,15]. Of all RHDUS studies analyzed, 7% showed evidence of RAS.…”

“…Univariate analysis in this study showed a significant association between previously documented hypertension and positive RDHUS for RAS (p=.018) and even stronger significance between hypertensive urgency or flash pulmonary edema on admission and positive RHDUS for RAS (p=.002). Examination for renal artery stenosis is indicated by resistant or poorly controlled blood pressure, coexisting atherosclerosis, kidney injury of unknown etiology, and atrophic or asymmetric kidneys [1,7]. This study confirms that poorly controlled hypertension or hypertensive urgency and/or flash pulmonary edema is a good indicator for a Doppler evaluation for RAS.…”

“…It has also been shown by many studies to have high sensitivity and specificity when compared to renal angiography, the gold standard for RAS detection [1,[5][6][7][8][9][10]. This exam includes direct visualization of the renal artery origin and evaluation of the renal poles for accessory and main artery branch stenosis.…”

Ultrasound diagnostics of renal artery stenosis

“…Studies conducted using CCDS (mostly after 1993) generally set the cut-off at 180–200 cm/s [ 8 , 19 , 24 , 27 , 40 , 42 ]. As peak velocities are determined using receiver operating characteristics (ROC) curves, they also always represent an evaluation performed by the author to assess sensitivity or specificity, positive predictive value (PPV) or negative predictive value (NPV).…”

Critical analysis of renal duplex ultrasound parameters in detecting significant renal artery stenosis

“…As shown by other reports, 5,6,[12][13][14][21][22][23][24][25][26][27] this current study demonstrates the feasibility and reliability of RDU imaging in diagnosing RAS. There is no ideal screening test for RAS; whereas some reports advocate MRA, 28,29 others recommend CTA. 28,30 At the current time, however, when cost-effectiveness is crucial, the most important characteristic of any screening test for RAS is to provide enough sensitivity and to guide the need for additional diagnostic and therapeutic modalities.…”