Abstract
ObjectivesTo explore the role of Contrast-enhanced ultrasound (CEUS) in the evaluation of patients with suspected renal artery stenosis and analyze the causes of the misdiagnosis and missed diagnosis.MethodsThe data of 40 patients (80 renal arteries) diagnosed with RAS by CEUS in Beijing Hospital from September 2018 to October 2020 were compared with their digital subtraction angiography (DSA) results to analyze the causes underlying missed diagnosis and misdiagnosis of RAS by CEUS.Results1. Compared with the gold standard DSA results, the AUC of the ROC curve of CEUS in detecting normal renal artery and renal artery stenosis was 0.961, the sensitivity was 96.4%, the specificity was 95.8%, and the Kappa value of the consistency analysis was 0.912 (P < 0.01); 2. Compared with the gold standard DSA results, the ROC curve of CEUS in distinguishing renal artery stenosis ≥70% from <70% stenosis has an AUC of 0.916, a sensitivity of 90.9%, a specificity of 92.3%, and the Kappa value of the consistency analysis is 0.77 (P < 0.01); 3. CEUS missed two cases (one for mild stenosis and one for moderate stenosis), and the detection rate of renal artery stenosis was 97.5% (78/80); A total of 65 renal arteries diagnosed by CEUS were consistent with DSA, and the diagnostic accuracy of CEUS for the degree of stenosis was 81.25% (65/80); Among the 13 misdiagnosed renal arteries, 4 of them can be corrected to the same degree as DSA by the reference to hemodynamic index, and the diagnosis rate of the degree of renal artery stenosis by ultrasonography (combined with CEUS and hemodynamic indicators) can be improved to 86.25%.Conclusions1. CEUS can clearly show the renal arteries, and is consistent with DSA in distinguishing normal renal artery stenosis from renal artery stenosis, as well as renal artery stenosis ≥70% and <70% stenosis; 2. CEUS showed good performance in detecting normal renal artery and renal artery stenosis, and the missed diagnosis is concentrated on mild and moderate stenosis; 3. CEUS combined with hemodynamic indicators (Doppler ultrasound) can improve the accurate diagnosis rate of renal artery stenosis by ultrasonography; 4. The most important factor for the accurate diagnosis of renal artery stenosis by CEUS is the operator's standardized examination, which is not only related to the duration of the operator has been engaged in this inspection, but also related to whether the operator has received professional training in relevant aspects. These all indicate the necessity and importance of the standardized operation of renal artery contrast-enhanced ultrasound examination, and professional training should be given to operators.
Highlights
Renal artery stenosis (RAS), which may lead to refractory hypertension and/or renal insufficiency, has been a substantial clinical concern [1]
contrastenhanced ultrasound (CEUS) and Digital subtraction angiography (DSA) findings were consistent in determining the degree of stenosis in 65 renal arteries, showing an accuracy rate of 81.25% (65/80)
For the cases in which hyperechoic plaques were presented in the arterial wall at stenotic sites, the blockage of the plaques resulted in relatively narrow contrast agent echoes in the residual renal lumen, leading to an overestimation of stenosis (3/15)
Summary
Renal artery stenosis (RAS), which may lead to refractory hypertension and/or renal insufficiency, has been a substantial clinical concern [1]. Instead, contrastenhanced ultrasound (CEUS), which uses contrast agents without hepatorenal toxic side effects, is especially suitable for patients allergic to ICAs or with renal insufficiency [6]. Ultrasound, the first-line imaging examination for RAS screening, commonly uses hemodynamic parameters for diagnosis [7], including peak systolic velocity (PSV), abdominal aortic velocity, the renalaortic ratio (RAR) of the PSV and the presence of tardus-parvus renal artery spectral waveforms. These parameters are affected by various factors, including metabolic status, blood pressure, vascular wall compliance, traveling course of the renal arteries and renal parenchymal lesions. The present study primarily used CEUS for RAS diagnosis; this approach determines the degree of RAS based on the morphology of the renal arteries, i.e., the change in vascular luminal diameter, and the CEUSbased diagnostic approach is based on principles and processes which is similar to DSA for the diagnosis of RAS
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