Utility of Doppler sonography for renal artery stenosis screening in obese children with hypertension

A preliminary study of renal function for renal artery stenosis using multiparametric magnetic resonance imaging

OBJECTIVE

To comprehensively evaluate the renal structure and function of patients with renal artery stenosis (RAS) using multiparametric magnetic resonance imaging (MRI), and analyze the correlation between magnetic resonance (MR) parameters and renal function.

MATERIALS AND METHODS

Renal multiparametric MRI was conducted on 62 patients with RAS utilizing a Philips Ingenia CX 3.0 T MRI system. The scanning protocols encompassed arterial spin labeling, phase contrast MRI, diffusion weighted imaging, T1 mapping, and blood oxygen level-dependent MRI. All patients underwent radionuclide renal dynamic imaging to calculate the glomerular filtration rate (GFR) for assessing renal function.

RESULTS

Most MR parameters were correlated with GFR: renal parenchymal volume (R = 0.603), whole kidney renal blood flow (RBF) (R = 0.192), renal cortical RBF (R = 0.294), renal artery mean velocity (R = 0.593), stroke volume (R = 0.599), mean flux (R = 0.629), renal cortical apparent diffusion coefficient (ADC) (R = 0.466), medullary ADC (R = 0.332), cortical T1 value (R = - 0.206), corticomedullary T1 difference (R = 0.204), cortical T2* value (R = 0.448), and medullary T2* value (R = 0.272). The best prediction model for GFR using multiparametric MRI was obtained, including renal PV, whole kidney RBF, cortical RBF, mean velocity, mean flux, and CMD T1.

CONCLUSION

Multiparametric MRI is a novel noninvasive examination method that can effectively and comprehensively assess the renal structure and function of RAS.

The Value of Contrast-Enhanced Ultrasound versus Doppler Ultrasound in Grading Renal Artery Stenosis

Objective

This study is aimed at exploring the accuracy of contrast-enhanced ultrasound (CEUS) in grading renal artery stenosis.

Methods

122 renal arteries with suspected renal artery stenosis were selected. DSA, DUS, and CEUS were performed for all patients with suspected renal artery stenosis in the research. DSA was selected as the gold standard. The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of CEUS or Doppler ultrasound (DUS) in the diagnosis of renal artery stenosis were analyzed. The consistency between CEUS and digital subtraction angiography (DSA) was compared. The accuracy of DUS or CEUS in grading renal artery stenosis was assessed by the area under the receiver operating characteristic (ROC) curves and compared between groups.

Results

The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of CEUS in the diagnosis of renal artery stenosis were 88.9%, 87.8%, 88.5%, 93.5%, and 80.0%, respectively. There was no significant difference in grading renal artery stenosis between CEUS and DSA (X² = 0.643, P = 0.424). 77 of the 122 renal arteries were diagnosed with the stenosis rate more than 30% by CEUS. Compared with the results of DSA, the kappa value of CEUS was 0.749 (P < 0.05).

Conclusion

CEUS is accurate in grading renal artery stenosis, and it may represent the method of choice in diagnosing renal artery stenosis.

Normative and pathological values of hemodynamic and Doppler ultrasound arterial findings in children

Doppler ultrasound is an effective, useful and remarkably powerful tool in pediatric imaging. If possible, its use is always favored to avoid exposure to radiation or sedatives. By waveform spectrum analysis, Doppler ultrasound reveals information on blood flow and details on normal physiology and pathological processes undiscernible from gray-scale imaging alone. However, Doppler ultrasound remains underused, largely due to the difficult interpretation of changes in Doppler waveforms during childhood. This article provides a narrative review of the literature regarding the normative values and the physiological arterial changes through childhood according to age, weight or height, as well as frequent pathological arterial findings in children, classified by arterial territory.