Objective: To evaluate the characteristics of renal cortical blood perfusion assessed by contrast-enhanced ultrasound (CEUS) in elderly patients with renal artery stenosis (RAS) and its relationship with renal function. Methods: Ninety-three elderly patients diagnosed with RAS, who were admitted in Beijing Hospital during June 2017 and December 2018, were retrospectively enrolled. According to the degree of RAS, 186 renal arteries were divided into normal renal artery group (n=79), mild RAS group (30% to 49%, n=59), moderate RAS group (50% to 70%, n=33), and severe RAS group (70% to 99%, n=15). Renal cortical blood perfusion and renal glomerular filtration rate (GFR) were measured by CEUS and radionuclide renal dynamic imaging. According to the renal GFR, 186 kidneys were divided into normal renal function group (GFR≥35 ml/min, n=42) and mild renal insufficiency group (35 ml/min>GFR≥25 ml/min, n=51), moderate renal insufficiency group (25 ml/min>GFR≥15 ml/min, n=75) and severe renal insufficiency group (GFR<15 ml/min, n=18). The renal cortical blood perfusion time-intensity curve (TIC) and related parameters were analyzed, including the area under the curve (AUC), the slope of the ascending branch (A), the peak intensity (PI), the peak time (TTP) and the mean transit time (MTT), the kidneys of different RAS groups and patients with different renal function groups were analyzed. Pearson correlation analysis was used to evaluate the correlation between renal cortical blood perfusion parameters and renal GFR. Results: (1) Renal cortical blood perfusion and GFR: CEUS showed that parameter A of TIC was significantly reduced, while TTP was prolonged in the mild renal artery stenosis group compared with the normal renal artery group (both P<0.05), GFP was similar between the two groups. Cortical perfusion parameters, such as AUC, A, PI and GFR were significantly lower, while TTP and MTT were significantly prolonged in the moderate and severe renal artery stenosis group than in the normal and mild stenosis groups (all P<0.05). Compared with the moderate stenosis group, AUC, A, PI and GFR were significantly lower while TTP, MTT were significantly prolonged in the severe renal artery stenosis group (all P<0.05). (2) TIC showed that the renal perfusion parameters, AUC, PI and A were significantly lower, while TTP was significantly longer in the mild renal dysfunction group than in the normal renal function group (all P<0.001). The changes aggravated in proportion with renal dysfunction. (3) Correlation between perfusion parameters and GFR: Pearson correlation analysis showed that the AUC (r=0.774, P<0.05), A (r=0.815, P<0.05) and PI (r=0.772, P<0.05) were positively correlated with GFR; serum creatinine level (r=-0.841, P<0.05), renal function grading (r=-0.731, P<0.05), TTP (r=-0.803, P<0.05) and MTT (r=-0.741, P<0.05) were negative correlated with GFR. The degree of stenosis was negatively correlated with GFR (r=-0.427, P<0.05). Conclusion Cortical perfusion parameters differ significantly among patients with various degree of RAS and renal dysfunction. The renal cortical blood perfusion parameters are correlated with renal GFR.

Objective:To investigate the imaging characteristics on contrast-enhanced ultrasound(CEUS)of carotid plaque instability and their correlation with histopathological changes in elderly patients.Methods:Twenty-three patients undergone carotid endarterectomy(CEA)at the Department of Neurosurgery of Beijing Hospital from June 2018 to November 2020 were retrospectively enrolled, including 27 males and 5 females, aging from 60 to 87(68.1±6.3)years.They were diagnosed with moderate to severe carotid artery stenosis(50%-99%)based on digital subtraction angiography(DSA).Carotid artery CEUS was conducted before surgery, and HE staining and CD34 immunohistochemical staining were used to record histopathological scores and microvessel density(MVD)counts.Results:The mean pathological score and MVD count were 2.46±0.66 and 37.17±12.88 for 32 cases with hypoechoic patterns, 22.42±0.55 and 38.06±13.66 for 18 cases with mixed echo patterns, and 2.75±0.35 and 23.50±9.192 for 2 cases with strong echo patterns, respectively.CEUS grading was positively correlated with histopathology score and MVD count( r=0.53、0.76, all P<0.01). Conclusions:Low echo and mixed echo plaques are more unstable than strong echo plaques.CEUS can be used to comprehensively assess the vulnerability of atherosclerotic plaques and to decide the optimal surgical time for patients with carotid atherosclerotic plaque stenosis.

Objective:To establish and validate a prognostic model of a contrast-enhanced ultrasound scoring(CEUS)system for evaluating renal artery stenosis(RAS)in the elderly.Methods:This was a single-center retrospective study.A total of 324 elderly RAS patients admitted to Beijing Hospital from October 2017 to July 2020 were randomly assigned into the model group(n=174)and the validation group(150)in a 1∶1 ratio.Clinical and imaging data of patients on admission including general conditions, previous medical history, blood pressure, blood creatinine, renal artery stenosis and cortical blood perfusion in the affected kidney and renal function(GFR)at 1-year follow-up were collected.Univariate and multivariate logistic regression was used to establish a model of the CEUS scoring system.The receiver operating characteristic(ROC)curve and area under the ROC curve(AUC)were used to evaluate prediction accuracy.Clinical application value of the CEUS scoring system model was evaluated via decision curve analysis using a nomogram.Results:Baseline clinical and radiomic data had no significant difference between the model group and the validation group( P>0.05). Multivariate logistic regression analysis results showed that age( OR=1.242, 95% CI: 1.081-1.427, P<0.01), diabetes( OR=1.545, 95% CI: 1.107-2.156, P<0.05), blood pressure( OR=1.328, 95% CI: 1.056-1.670, P<0.05), renal function( OR=2.374, 95% CI: 1.216-3.887, P<0.01)and cortical blood perfusion parameter( OR=2.646, 95% CI: 1.553-6.369, P<0.01)were risk factors for the deterioration of renal function during 1 year follow-up.Based on these results, a nomogram for the CEUS scoring system model was drawn, and its consistency index, the C-Index, was 0.725(95% CI: 0.653-0.776). The AUC of the CEUS scoring system was 0.824 and the Youden index was 0.711 in the model group, with a specificity of 0.774 and a sensitivity of 0.837.The AUC of the CEUS scoring system was 0.853 and the Youden index was 0.715 in the validation group, with a specificity of 0.684 and a sensitivity of 0.889.There was no significant difference in ROC curve between the two groups( D=1.387, P>0.05). In addition, calibration charts of the two models showed that the calibration curve of the CEUS scoring system was close to the standard curve, with no statistically significant difference( P>0.05). Conclusions:The CEUS scoring system model can be used to predict the risk of worsening renal function in elderly RAS patients during 1-year follow-up.