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In this large trial, denervation of the kidneys with use of a radiofrequency ablation catheter in the renal arteries had no significant effect on blood pressure in patients with resistant hypertension. This contradicts results of smaller trials that did not include a sham control. Because of the aging of the population and rising rates of obesity, hypertension is increasing in prevalence worldwide. 1 Approximately 10% of patients with diagnosed hypertension have resistant hypertension, defined as a systolic blood pressure of 140 mm Hg or higher despite adherence to at least three maximally tolerated doses of antihypertensive medications from complementary classes, including a diuretic at an appropriate dose. 1 – 4 Patients with resistant hypertension who are receiving appropriate medical therapy have high rates of cardiovascular complications, with few treatment options. The sympathetic nervous system — in particular, sympathetic cross-talk between the kidneys and the brain — appears . . .

PurposeTo assess image quality and diagnostic accuracy of low-dose computed tomography (CT) angiography using adaptive statistical iterative reconstruction V (ASiR-V) for evaluating the anatomy of renal vasculature in potential living renal donors.Materials and methodsEighty of 100 potential living renal donors were prospectively enrolled and underwent multiphase CT angiography (e.g., unenhanced, arterial, and venous phases) to evaluate the kidney for donation. Either low-dose using ASiR-V or standard protocol was randomly applied. Image quality was analyzed qualitatively and quantitatively with contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR). Renal artery and vein number, early branching vessel from renal arteries, and drainage of left-sided ascending lumbar vein to left renal vein were assessed. Reference standard for renal vasculature was surgical confirmation.ResultsSize-specific dose estimate of low-dose CT angiography (9.5 ± 0.8 mGy) was significantly lower than standard CT angiography (22.7 ± 4.1 mGy) (p < 0.001). Thus, radiation dose was reduced by 58.2% with low-dose CT. Both CNR and SNR of low-dose CT were significantly higher than those of standard CT (p < 0.001). Between the two CT methods, image quality was similar qualitatively (p > 0.05). Of 80 participants, 44 (55.0%) underwent nephrectomy. Both CT methods accurately predicted the anatomy of renal vasculature (standard CT, 100% for all variables; low-dose CT, 96.6% for renal vessel number or early branching vessel and 85.7% for drainage of left-sided ascending lumbar vein to left renal vein; p > 0.05 for all comparisons).ConclusionLow-dose CT angiography using ASiR-V is useful to evaluate renal vasculature for potential living renal donors.Key Points• In this prospective study, adaptive statistical iterative reconstruction V (ASiR-V) allowed 58.2% dose reduction while maintaining diagnostic image quality for renal vessels.• As compared with the standard protocol, the dose with ASiR-V was significantly lower (9.5 ± 0.8 mGy) than with standard computed tomography (CT) angiography (22.7 ± 4.1 mGy).• Low-dose CT using ASiR-V is useful for living donor evaluation before nephrectomy.

Renal sympathetic hyperactivity is associated with hypertension and its progression, chronic kidney disease, and heart failure. We did a proof-of-principle trial of therapeutic renal sympathetic denervation in patients with resistant hypertension (ie, systolic blood pressure ≥160 mm Hg on three or more antihypertensive medications, including a diuretic) to assess safety and blood-pressure reduction effectiveness. We enrolled 50 patients at five Australian and European centres; 5 patients were excluded for anatomical reasons (mainly on the basis of dual renal artery systems). Patients received percutaneous radiofrequency catheter-based treatment between June, 2007, and November, 2008, with subsequent follow-up to 1 year. We assessed the effectiveness of renal sympathetic denervation with renal noradrenaline spillover in a subgroup of patients. Primary endpoints were office blood pressure and safety data before and at 1, 3, 6, 9, and 12 months after procedure. Renal angiography was done before, immediately after, and 14–30 days after procedure, and magnetic resonance angiogram 6 months after procedure. We assessed blood-pressure lowering effectiveness by repeated measures ANOVA. This study is registered in Australia and Europe with ClinicalTrials.gov, numbers NCT 00483808 and NCT 00664638. In treated patients, baseline mean office blood pressure was 177/101 mm Hg (SD 20/15), (mean 4·7 antihypertensive medications); estimated glomerular filtration rate was 81 mL/min/1·73m 2 (SD 23); and mean reduction in renal noradrenaline spillover was 47% (95% CI 28–65%). Office blood pressures after procedure were reduced by −14/−10, −21/−10, −22/−11, −24/−11, and −27/−17 mm Hg at 1, 3, 6, 9, and 12 months, respectively. In the five non-treated patients, mean rise in office blood pressure was +3/−2, +2/+3, +14/+9, and +26/+17 mm Hg at 1, 3, 6, and 9 months, respectively. One intraprocedural renal artery dissection occurred before radiofrequency energy delivery, without further sequelae. There were no other renovascular complications. Catheter-based renal denervation causes substantial and sustained blood-pressure reduction, without serious adverse events, in patients with resistant hypertension. Prospective randomised clinical trials are needed to investigate the usefulness of this procedure in the management of this condition. Ardian Inc.

The intrarenal resistive index is often measured to assess allograft status, but its value is unclear. This study showed that the resistive index, measured at predefined times after transplantation, reflects recipient factors but not intrinsic characteristics of the allograft. In many renal-transplantation centers, measurement of the intrarenal resistive index by means of Doppler ultrasonography is routinely used to evaluate renal allografts. 1 , 2 The resistive index is derived from the pulsatile flow-velocity waveform. In native kidneys, a higher resistive index, as compared with a lower resistive index, is a significant predictor of progressive renal dysfunction and adverse cardiovascular events. 3 – 9 A previous cross-sectional study linked an increased intrarenal resistive index after kidney transplantation with an increased risk of graft loss or recipient death. 10 Although these data suggest that the intrarenal resistive index reflects the intrinsic state of the allograft, it . . .

To evaluate the function of kidneys with renal artery stenosis using multiparametric magnetic resonance imaging, assess the diagnostic efficacy of multiparametric magnetic resonance imaging for single kidney dysfunction. Renal multiparametric magnetic resonance imaging was performed on 62 patients with RAS using the Philips Ingenia CX 3.0 T MRI machine. The scanning sequences included arterial spin labeling, phase contrast MRI, diffusion weighted imaging, T1 mapping, and blood oxygen level-dependent MRI. All patients underwent radionuclide renal dynamic imaging, and the glomerular filtration rate (GFR) was calculated to determine renal function. Individual kidneys from renal artery stenosis patients were classified into normal (GFR ≥ 30) and reduced (GFR < 30) groups and the ability of the uni- and multi-variate logistic regression model to predict the group was determined. MR parameters demonstrated considerable diagnostic efficacy for single kidney dysfunction, with AUC range of 0.597- 0.864. The strongest predictor was mean renal artery blood flow. The sensitivity and specificity were 0.93 and 0.69AUC was 0.864. The strongest predictors of the renal microstructure were cortical apparent diffusion coeffecient and T1 value, with ROC AUCs of 0.756 and 0.741, sensitivities of 0.875 and 0.689, and specificities of 0.537 and 0.731. Multiparametric MRI combined with the values of cortical renal blood flow and cortical T1 exhibited the highest diagnostic efficacy, with an AUC of 0.92, and sensitivity of 0.919, and specificity of 0.743. Multiparametric magnetic resonance imaging can effectively detect the single renal dysfunction of kidneys with renal artery stenosis, which holds promise for the diagnosis and prognosis of patients with renal artery stenosis.

Introduction Renal infarction is an extremely rare condition occurring in the context of structural or functional cardiac abnormalities, renal artery injury or coagulative syndromes. Although the clinical presentation of renal infarction is often nonspecific, the presence of symptoms such as back pain, high blood pressure, nausea and fever should raise suspicion, particularly in the emergency setting. Timely diagnosis is crucial for preserving renal function, whether through minimally invasive procedures or bypass surgery. Case presentation We present a case of a young male who developed acute occlusion of an aortic-renal bypass supplying a solitary left kidney. The patient exhibited resistant arterial hypertension and acute oligo-anuric kidney injury requiring dialysis. Despite the total occlusion of the aorto-renal bypass on imaging, doppler ultrasound demonstrated moderate renal tissue perfusion, likely maintained via collateral vasculature. The existence of a previous prolonged ischemic condition may have led to the formation of collateral-dependent circulation. While insufficient for pressure-dependent diuresis, the collateral flow preserved renal tissue oxygenation. Conclusions Collateral perfusion should be evaluated in cases of renal infarction, particularly when the main renal artery is occluded. Adequate collateral circulation might preserve renal tissue viability beyond the typical ischemic window.

Percutaneous-transluminal renal angioplasty (PTRA) and stenting aim to halt the progression of kidney disease in patients with renal artery stenosis (RAS), but its outcome is often suboptimal. We hypothesized that a model incorporating markers of renal function and oxygenation extracted using radiomics analysis of blood oxygenation-level dependent (BOLD)-MRI images may predict renal response to PTRA in swine RAS. Twenty domestic pigs with RAS were scanned with CT and BOLD MRI before and 4 weeks after PTRA. Stenotic (STK) and contralateral (CLK) kidney volume, blood flow (RBF), and glomerular filtration rate (GFR) were determined, and BOLD-MRI R2 * maps were generated before and after administration of furosemide, a tubular reabsorption inhibitor. Radiomics features were extracted from pre-PTRA BOLD maps and Robust features were determined by Intraclass correlation coefficients (ICC). Prognostic models were developed to predict post-PTRA renal function based on the baseline functional and BOLD-radiomics features, using Lasso-regression for training, and testing with resampling. Twenty-six radiomics features passed the robustness test. STK oxygenation distribution pattern did not respond to furosemide, whereas in the CLK radiomics features sensitive to oxygenation heterogeneity declined. Radiomics-based model predictions of post-PTRA GFR (r = 0.58, p = 0.007) and RBF (r = 0.68; p = 0.001) correlated with actual measurements with sensitivity and specificity of 92% and 67%, respectively. Models were unsuccessful in predicting post-PTRA systemic measures of renal function. Several radiomics features are sensitive to cortical oxygenation patterns and permit estimation of post-PTRA renal function, thereby distinguishing subjects likely to respond to PTRA and stenting. [Display omitted] •MR oxygenation maps unveil tissue engagement, and hypoxia susceptibility.•Radiomics mines spatial kidney oxygenation patterns characteristics.•Oxygenation heterogeneity may predict stenting kidney outcomes.•Heterogeneity signals tubular health; grave harm lessens revascularization gains.•Radiomics-guided renal BOLD probes noninvasively into histological tissue damage.

Accurate selection of sampling positions is critical in renal artery ultrasound examinations, and the potential of utilizing deep learning (DL) for assisting in this selection has not been previously evaluated. This study aimed to evaluate the effectiveness of DL object detection technology applied to color Doppler sonography (CDS) images in assisting sampling position selection. A total of 2004 patients who underwent renal artery ultrasound examinations were included in the study. CDS images from these patients were categorized into four groups based on the scanning position: abdominal aorta (AO), normal renal artery (NRA), renal artery stenosis (RAS), and intrarenal interlobular artery (IRA). Seven object detection models, including three two-stage models (Faster R-CNN, Cascade R-CNN, and Double Head R-CNN) and four one-stage models (RetinaNet, YOLOv3, FoveaBox, and Deformable DETR), were trained to predict the sampling position, and their predictive accuracies were compared. The Double Head R-CNN model exhibited significantly higher average accuracies on both parameter optimization and validation datasets (89.3 ± 0.6% and 88.5 ± 0.3%, respectively) compared to other methods. On clinical validation data, the predictive accuracies of the Double Head R-CNN model for all four types of images were significantly higher than those of the other methods. The DL object detection model shows promise in assisting inexperienced physicians in improving the accuracy of sampling position selection during renal artery ultrasound examinations.

PurposeTo evaluate image quality of non-contrast-enhanced magnetic resonance angiography (MRA) and compare transplant renal artery stenosis (TRAS) seen by non-contrast-enhanced MRA with digital subtraction angiography (DSA) as the gold standard.Materials and methods330 patients receiving 369 non-contrast-enhanced MRA examinations from July 2014 to June 2017 were included. Thirty patients received at least two MRA examinations. Image quality was independently assessed by two radiologists. Inter-observer agreement was analyzed. Transplant renal artery anatomy and complications were evaluated and compared with DSA. If possible, accuracy was calculated on a per-artery basis.ResultsGood or excellent image quality was found in 95.4 % (352/369) of examinations with good inter-observer agreement (K=0.760). Twenty-two patients with DSA had 28 non-contrast-enhanced MRA examinations within a 2-month period. Of these, 19 patients had TRAS, two patients had pseudoaneurysms, and one patient had a normal transplant renal artery but an occluded external iliac artery. Non-contrast-enhanced MRA correctly detected 19 TRAS and nine normal arteries, giving 96.6 % accuracy on a per-artery basis.ConclusionsNon-contrast-enhanced MRA demonstrates a good depiction of the transplanted renal artery and shows good correlation with DSA in cases where there was TRAS.Key Points• Good or excellent image quality was found in 95.4 % of examinations.• Non-contrast-enhanced MRA can clearly map transplant renal artery anatomy.• Non-contrast-enhanced MRA is a reliable tool to detect TRAS.

Summary Objective The aim of this study was to evaluate the radiation dose and renal cell carcinoma conspicuity with virtual unenhanced images and split‐bolus injection from spectral multidetector CT (MDCT). Material and methods This prospective study was approved by the Ethics Committee, and informed consent was obtained. Ninety suspected patients of renal cell carcinoma diagnosed by abdominal ultrasonography and CEUS were randomly divided into two groups by a radiographer. Patients of the first group underwent spectral MDCT with virtual unenhanced imaging and split‐bolus injection, while patients in the second group underwent conventional unenhanced as well as tri‐phasic enhanced CT. Group A (split‐bolus spectral MDCT group): The contrast material was administered at a dose of 1.5 mL/kg body weight at a flow rate of 4 mL/s, with a ratio of 7 to 5 before the CT scan with an interval of 60 seconds. Virtual unenhanced images were generated using a standard three‐material decomposition algorithm, and the best mono‐energy (keV) was calculated to show the tumour, renal artery and renal vein. Group B (conventional tri‐phasic enhanced CT group): the contrast agent was injected with a dose of 1.5 mL/kg body weight at a flow rate of 4 mL/s. The corticomedullary phase scanning was performed once the arterial CT value reached 100 HU; the nephrographic phase was scanned 60 seconds later. And the excretory phase was scanned 5 min after onset of contrast injection. The LKR (lesion kidney ratio), CNR, and CT value of the corticomedullary and nephrographic phase were measured. The opacification of the renal collection system (including calices, infundibula and renal pelvis) was scored. The radiation dose was recorded. Statistical analysis was performed using Student's t‐test, Fisher's exact test, the Mann–Whitney U‐test, and k statistics. Results There were no statistically significant differences between the two groups in age, sex and body mass index (BMI), but there was significant difference in treatment methods. The best mono‐energy was 58 keV for showing the tumour and renal artery and 67 keV for showing the renal vein. There were no differences in the mean attenuations of normal renal parenchyma, renal tumour, CNR, and imaging quality between true unenhanced images and virtual unenhanced images from the combined corticomedullary and nephrographic phase. The LKR of the mono‐energy at 58 keV from the combined corticomedullary and nephrographic phase was significantly better than the corticomedullary phase of the conventional enhanced CT scan (0.74±0.18 vs 1.08±0.34, P<.01), but there was no difference in CNR (2.31±1.74 vs 2.79±1.83, P>.05). There were no differences in the CT values of the renal tumour, normal renal parenchyma and renal artery between the two groups (P>.05). The CT value of the renal vein at mono‐energy (67 keV) (200.55±43.38) from the combined corticomedullary and nephrographic phase was higher than the conventional CT scan (140.90±42.64) in the nephrographic phase. The Kappa scores of the rate of the renal collection system for the conventional CT and spectral CT were 0.68 (95% confidence interval [CI]: 0.35–0.89) and 0.54 (95% CI: 0.30–0.88), respectively. The radiation dose (735±162 mGy·cm) of Group A was significantly less than that of Group B (1032±324 mGy·cm) (P<.01). Conclusion Conspicuity with virtual unenhanced imaging and split‐bolus injection from spectral multidetector CT is better than or equal to the conventional three‐phase enhanced CT scan in showing the RCC, renal artery and renal vein, while the radiation dose can be reduced by 28.78%.