Assessment of renal congestion in a rat model with congestive heart failure using superb microvascular imaging.

PURPOSE: Renal congestion is a therapeutic target in congestive heart failure. However, its detailed evaluation in a clinical setting is challenging. This study sought to assess renal congestion impairment using superb microvascular imaging (SMI), a simple and accessible method. METHODS: Dahl salt-sensitive rats, used as a model for congestive heart failure, underwent central venous pressure (CVP) measurements. Renal congestion was evaluated through measurements of renal medullary pressure (RMP) and assessment of renal perfusion using contrast-enhanced ultrasonography at both the early (control group) and heart failure phases (HF group). All rats were assessed with SMI. The region of interest (ROI) was set in interlobular vessels, interlobar vessels, and a combination of these areas. The area ratio was calculated from the color pixel count in the ROI divided by the total pixel count in the ROI. Intrarenal perfusion index (IRPI) was defined as (maximum area ratio-minimum area ratio) / maximum area ratio. RESULTS: There were no significant differences in renal function and left ventricular ejection fraction between the two groups. CVP, time-to-peak (TTP) in the medulla, and RMP were higher in the HF group than in the control group. In the HF group, IRPI, evaluated in the interlobular vessels, was significantly higher than in the control group. IRPI was positively correlated with TTP in the medulla (p = 0.028, R = 0.60) and RMP (p < 0.001, R = 0.84), indicating that IRPI reflected renal congestion. CONCLUSIONS: IRPI is a useful tool for assessing renal congestion in rats with congestive heart failure.

Magnetic Resonance Imaging to Evaluate Kidney Structure, Function, and Pathology: Moving Toward Clinical Application.

Recent advances in multiparametric magnetic resonance imaging (MRI) allow multiple quantitative measures to assess kidney morphology, tissue microstructure, oxygenation, kidney blood flow, and perfusion to be collected in a single scan session. Animal and clinical studies have investigated the relationship between the different MRI measures and biological processes, although their interpretation can be complex due to variations in study design and generally small participant numbers. However, emerging themes include the apparent diffusion coefficient derived from diffusion-weighted imaging, T1 and T2 mapping parameters, and cortical perfusion being consistently associated with kidney damage and predicting kidney function decline. Blood oxygen level-dependent (BOLD) MRI has shown inconsistent associations with kidney damage markers but has been predictive of kidney function decline in several studies. Therefore, multiparametric MRI of the kidneys has the potential to address the limitations of existing diagnostic methods to provide a noninvasive, noncontrast, and radiation-free method to assess whole kidney structure and function. Barriers to be overcome to facilitate widespread clinical application include improved understanding of biological factors that impact MRI measures, development of a larger evidence base for clinical utility, standardization of MRI protocols, automation of data analysis, determining optimal combination of MRI measures, and health economic evaluation.

Arterial spin labeling and diffusion-weighted MR imaging: quantitative assessment of renal pathological injury in chronic kidney disease.

PURPOSE: The aim of the study was to investigate the performance of arterial spin labeling (ASL), diffusion-weighted imaging (DWI), and clinical biomarkers in assessing renal pathological injury in CKD. MATERIALS AND METHODS: Forty-five biopsy-proven CKD patients and 17 healthy volunteers underwent DWI and ASL examinations. Renal cortical blood flow (RBF) and apparent diffusion coefficient (ADC) values were acquired. Correlations between RBF, ADC, serum creatinine (SCr), estimated glomerular filtration rate (eGFR), and pathological scores were assessed. The diagnostic efficacy of SCr, eGFR, RBF, and ADC in assessing renal pathological injury was assessed by ROC curve analysis. RESULTS: The cortical RBF, ADC, SCr, and eGFR were significantly correlated with the renal histology score (all p < 0.01). The AUC values of SCr, eGFR, RBF, and ADC were 0.705 (95% confidence interval (CI): 0.536-0.827), 0.718 (0.552-0.839), 0.823 (0.658-0.916), and 0.624 (0.451-0.786), respectively, in discriminating the minimal-mild renal pathological injury group (N = 30) from the control group (N = 17). The diagnostic ability of ASL was significantly higher than that of DWI (p = 0.049) and slightly but not significantly higher than that of eGFR and SCr (p = 0.151 and p = 0.129, respectively). When compared with that of eGFR, the sensitivity of ASL in detecting early renal injury increased from 50 to 70% (p = 0.014). However, in differentiating between the minimal-mild and moderate-severe renal injury groups (N = 15), there was no significant difference in diagnostic ability among the four parameters (all p > 0.05). CONCLUSION: ASL is practicable for noninvasive evaluation of renal pathology, especially for predicting early renal pathological injury in CKD patients.

Bias and Precision in Magnetic Resonance Imaging-Based Estimates of Renal Blood Flow: Assessment by Triangulation.

BACKGROUND: Renal blood flow (RBF) can be measured with dynamic contrast enhanced-MRI (DCE-MRI) and arterial spin labeling (ASL). Unfortunately, individual estimates from both methods vary and reference-standard methods are not available. A potential solution is to include a third, arbitrating MRI method in the comparison. PURPOSE: To compare RBF estimates between ASL, DCE, and phase contrast (PC)-MRI. STUDY TYPE: Prospective. POPULATION: Twenty-five patients with type-2 diabetes (36% female) and five healthy volunteers (HV, 80% female). FIELD STRENGTH/SEQUENCES: A 3 T; gradient-echo 2D-DCE, pseudo-continuous ASL (pCASL) and cine 2D-PC. ASSESSMENT: ASL, DCE, and PC were acquired once in all patients. ASL and PC were acquired four times in each HV. RBF was estimated and split-RBF was derived as (right kidney RBF)/total RBF. Repeatability error (RE) was calculated for each HV, RE = 1.96 × SD, where SD is the standard deviation of repeat scans. STATISTICAL TESTS: Paired t-tests and one-way analysis of variance (ANOVA) were used for statistical analysis. The 95% confidence interval (CI) for difference between ASL/PC and DCE/PC was assessed using two-sample F-test for variances. Statistical significance level was P < 0.05. Influential outliers were assessed with Cook's distance (Di > 1) and results with outliers removed were presented. RESULTS: In patients, the mean RBF (mL/min/1.73m2 ) was 618 ± 62 (PC), 526 ± 91 (ASL), and 569 ± 110 (DCE). Differences between measurements were not significant (P = 0.28). Intrasubject agreement was poor for RBF with limits-of-agreement (mL/min/1.73m2 ) [-687, 772] DCE-ASL, [-482, 580] PC-DCE, and [-277, 460] PC-ASL. The difference PC-ASL was significantly smaller than PC-DCE, but this was driven by a single-DCE outlier (P = 0.31, after removing outlier). The difference in split-RBF was comparatively small. In HVs, mean RE (±95% CI; mL/min/1.73 m2 ) was significantly smaller for PC (79 ± 41) than for ASL (241 ± 85). CONCLUSIONS: ASL, DCE, and PC RBF show poor agreement in individual subjects but agree well on average. Triangulation with PC suggests that the accuracy of ASL and DCE is comparable. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 2.

Ultrasonographic assessment of renal perfusion in bitches with mammary carcinoma treated with long-term carprofen.

The aim of this study was to evaluate renal hemodynamics, routine clinical and laboratory parameters used to estimate renal function, and clinical evolution during six months in bitches with mammary carcinomas that underwent mastectomy and were treated (TG) or not (CG) with carprofen for three months after surgery. Twenty-six bitches with mammary carcinoma were equally distributed into TG that received carprofen 4.4 mg/kg/day for 90 days and CG that did not receive anti-inflammatory medication. Renal artery Doppler flowmetry, contrast-enhanced ultrasound (CEUS) of renal parenchyma, haematological, biochemical and clinical analyses were obtained once a month. These data were compared between groups and time via analysis of variance (ANOVA) in a completely randomized design with repeated measures (P < 0.05). On B-mode ultrasound, the area of the renal artery was greater (P = 0.0003) in the TG. Regarding laboratory findings, haematocrit and haemoglobin were similar in both groups, showing a significant and gradual increase after three months of treatment; MCV, MHC, and MCHC were increased (P < 0.05) and lymphocyte and band counts decreased (P < 0.05) in the TG. Regarding biochemical tests, ALT was the only parameter with a significant difference, being higher (P = 0.0272) in the treated group. It can be concluded that the use of carprofen for 90 days causes minimal changes in renal perfusion, erythrocyte parameters and ALT activity, and reduces the proportion of blood inflammatory cells. Therefore, use of this medication can be carried out safely in patients who require auxiliary cancer treatment.

Quantitative Assessment of Renal Perfusion and Oxygenation by Invasive Probes: Basic Concepts.

Renal tissue hypoperfusion and hypoxia are early key elements in the pathophysiology of acute kidney injury of various origins, and may also promote progression from acute injury to chronic kidney disease. Here we describe basic principles of methodology to quantify renal hemodynamics and tissue oxygenation by means of invasive probes in experimental animals. Advantages and disadvantages of the various methods are discussed in the context of the heterogeneity of renal tissue perfusion and oxygenation.This chapter is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This introduction chapter is complemented by a separate chapter describing the experimental procedure and data analysis.

Application of dynamic contrast enhanced ultrasound in the assessment of kidney diseases.

PURPOSE OF REVIEW: Many forms of acute and chronic disease are linked to changes in renal blood flow, perfusion, vascular density and hypoxia, but there are no readily available methods to assess these parameters in clinical practice. Dynamic contrast enhanced ultrasound (DCE-US) is a method that provides quantitative assessments of organ perfusion without ionising radiation or risk of nephrotoxicity. It can be performed at the bedside and is suitable for repeated measurements. The purpose of this review is to provide updates from recent publications on the utility of DCE-US in the diagnosis or assessment of renal disease, excluding the evaluation of benign or malignant renal masses. RECENT FINDINGS: DCE-US has been applied in clinical studies of acute kidney injury (AKI), renal transplantation, chronic kidney disease (CKD), diabetic kidney disease and to determine acute effects of pharmacological agents on renal haemodynamics. DCE-US can detect changes in renal perfusion across these clinical scenarios and can differentiate healthy controls from those with CKD. In sepsis, reduced DCE-US measures of perfusion may indicate those at increased risk of developing AKI, but this requires confirmation in larger studies as there can be wide individual variation in perfusion measures in acutely unwell patients. Recent studies in transplantation have not provided robust evidence to show that DCE-US can differentiate between different causes of graft dysfunction, although it may show more promise as a prognostic indicator of graft function 1 year after transplant. DCE-US can detect acute haemodynamic changes in response to medication that correlate with changes in renal plasma flow as measured by para-aminohippurate clearance. SUMMARY: DCE-US shows promise and has a number of advantages that make it suitable for the assessment of patients with various forms of kidney disease. However, further research is required to evidence its reproducibility and utility before clinical use can be advocated.

Assessment of Renal Perfusion in Transplanted Kidney Patients Using Pseudo-Continuous Arterial Spin Labeling with Multiple Post-Labeling Delays.

PURPOSE: To investigate technical issues for implementing pseudo-continuous arterial spin labeling (pCASL) for renal perfusion measurements in transplanted kidney patients (TK) in the early postoperative recovery phase. METHODS: Eleven subjects were scanned: TK (N = 4, 42 ±â€¯8.1Y) and normal volunteers (NV) (N = 7, 25 ±â€¯3Y). In 3.0 T clinical MRI, pCASL with a 2D balanced steady-state free precession readout was applied with four different post-labeling delays: 0.5/1.0/1.5/2.0 s. Perfusion images were acquired with and without background suppression and processed with and without registration for comparison. Renal blood flow (RBF) and arterial transit time (ATT) values were calculated from each pixel of images. The F-test, Wilcoxon signed-rank test, and Wilcoxon rank-sum test were used for statistical analyses. RESULTS: Background suppression decreased signal variations for both NV and TK. Registration suppressed effects of kidney motion for NV, which was not critical for TK. The renal cortex showed greater perfusion than the renal medulla in both NV and TK(p < 0.01). TK showed greater renal perfusion than NV(p < 0.05). Cortical and medullary RBF values were 271.8 ±â€¯43.5, 119.1 ±â€¯15.1 ml/100 g/min for NV and 358.3 ±â€¯36.4, 141.0 ±â€¯11.5 ml/100 g/min for TK. TK showed longer ATT values than NV(p < 0.01). ATT values in the cortex and medulla were 641 ±â€¯141 and 746 ±â€¯150 ms for NV and 919 ±â€¯49 and 935 ±â€¯81 ms for TK. CONCLUSIONS: We demonstrated that although there is no discernible motion of the transplanted kidney, background suppression is necessary to suppress signal fluctuations in renal perfusion measurements. Also, relatively high RBF and long ATT values were observed in the transplanted kidneys in the early postoperative recovery phase, which requires further longitudinal studies.

Ultrasonography-Based Dynamic Assessment on an Adult for Postoperative Effects of Double Kidney Transplant From a 6-Month-Old Donor.

To allow improved quality of life, renal transplant has been regarded as the best therapeutic option for patients with end-stage renal disease. However, due to shortages of renal sources, annually, only a few patients with renal failure can receive transplants, with most patients requiring hemodialysis to maintain their life. With increasing imbalance of demands and supplies for donor organs, infant organ donors have become an important part of domestic and foreign transplant sources. It is of great importance to guarantee successful kidney transplant outcomes. Examination of the size and blood perfusion of the transplanted kidneys in an accurate and timely manner and early detection of postoperative complications can improve survival rates and quality of life. Here, we report a rare double kidney transplant with the kidney of a 6-month-old infant and the great technical difficulties. Color Doppler ultrasonography played an important role in dynamic observations of the size of the kidney, blood perfusion, spectral index, and detection of complications after transplant.

Quantitative assessment of renal structural and functional changes in chronic kidney disease using multi-parametric magnetic resonance imaging.

BACKGROUND: Multi-parametric magnetic resonance imaging (MRI) provides the potential for a more comprehensive non-invasive assessment of organ structure and function than individual MRI measures, but has not previously been comprehensively evaluated in chronic kidney disease (CKD). METHODS: We performed multi-parametric renal MRI in persons with CKD (n = 22, 61 ± 24 years) who had a renal biopsy and measured glomerular filtration rate (mGFR), and matched healthy volunteers (HV) (n = 22, 61 ± 25 years). Longitudinal relaxation time (T1), diffusion-weighted imaging, renal blood flow (phase contrast MRI), cortical perfusion (arterial spin labelling) and blood-oxygen-level-dependent relaxation rate (R2*) were evaluated. RESULTS: MRI evidenced excellent reproducibility in CKD (coefficient of variation <10%). Significant differences between CKD and HVs included cortical and corticomedullary difference (CMD) in T1, cortical and medullary apparent diffusion coefficient (ADC), renal artery blood flow and cortical perfusion. MRI measures correlated with kidney function in a combined CKD and HV analysis: estimated GFR correlated with cortical T1 (r = -0.68), T1 CMD (r = -0.62), cortical (r = 0.54) and medullary ADC (r = 0.49), renal artery flow (r = 0.78) and cortical perfusion (r = 0.81); log urine protein to creatinine ratio (UPCR) correlated with cortical T1 (r = 0.61), T1 CMD (r = 0.61), cortical (r = -0.45) and medullary ADC (r = -0.49), renal artery flow (r = -0.72) and cortical perfusion (r = -0.58). MRI measures (cortical T1 and ADC, T1 and ADC CMD, cortical perfusion) differed between low/high interstitial fibrosis groups at 30-40% fibrosis threshold. CONCLUSION: Comprehensive multi-parametric MRI is reproducible and correlates well with available measures of renal function and pathology. Larger longitudinal studies are warranted to evaluate its potential to stratify prognosis and response to therapy in CKD.

Direct venous pressure assessment pre-renal transplantation to optimise graft venous drainage.

BACKGROUND: Renal transplantation is the modality of choice in the treatment of end-stage kidney disease. Surgically challenging aspects of renal transplantation may include creation of vascular anastomoses where there is complex vascular anatomy. We present a paediatric case of living-related donor (LRD) renal transplantation in whom direct intravenous pressure measurement guided the management of the vascular anastomoses in the context of inferior vena cava (IVC) obstruction. CASE-DIAGNOSIS/TREATMENT: During venography for transplant assessment, 150 mL of 0.9% sodium chloride was infused for over 20 s into well-developed collateral paravertebral veins to simulate the anticipated high-volume venous return from an implanted kidney. Direct venous pressure measurements were 20 mmHg in the right paravertebral vein and 19 mmHg in the left paravertebral vein. We were reassured by this result that the collateralised venous system could sustain the high venous drainage and maintain the arteriovenous (AV) gradient required for adequate graft perfusion. Intra-operative measurement at the time of transplantation, following release of venous clamps, of 22 mmHg supported the validity of this approach. CONCLUSIONS: In children with complex venous anatomy pre-transplant, direct intravenous pressure measurement may provide a useful adjunct in deciding which vessel is most suitable for transplant anastomosis.

An assessment of the utility and repeatability of the renal resistive index in horses.

The aim of this study was to establish the value of the renal resistive index (RI) of intrarenal arteries in healthy warmblood non-racing horses of different ages to assess the influence of physiologic factors and repeatability of measurement. The kidney ultrasonography examination was performed in three age groups: 15 foals, 15 adults and 15 elderly horses. The procedure was performed in unsedated standing animals. RI values were measured using pulsed-wave Doppler at the medial part of each kidney in the intrarenal arteries. To evaluate repeatability, all measurements were repeated two hours after the first examination. Statistical analysis of the relationship between groups was carried out using Fisher's test. The relationship between the RI value and the physiological parameters was evaluated using linear regression. Repeatability of measurements was determined based on the Bland-Altman plot. The mean RI value in the studied horses was 0.48 ± 0.05 in the left kidney and 0.49 ± 0.05 in the right kidney. There were no statistically significant differences between the RI values in foals and adult horses. The elderly horses had a significantly higher RI value. Pulse pressure was the only physiological parameter affecting the RI value. The repeatability coefficient was 0.089 for the right kidney and 0.09 for the left kidney. The presented result suggest that elderly healthy horses have higher RI values than younger animals, which should be taken into account in clinical practice. The arterial pulse pressure should also be considered when interpreting RI values. The measurements have high repeatability, but in the authors' opinion, this procedure is time consuming and requires experience.

Assessment of cerebral and renal autoregulation using near-infrared spectroscopy under normal, hypovolaemic and postfluid resuscitation conditions in a swine model: An observational study.

BACKGROUND: The impact of blood pressure changes on tissue oxygenation differs between vital organs and with blood volume conditions. OBJECTIVE: To assess cerebral and renal autoregulation simultaneously and compare the impact of blood pressure, hypovolaemia and fluid resuscitation on tissue oxygenation using near-infrared spectroscopy. DESIGN: Animal observational study. SETTING: An animal laboratory in Hamamatsu University School of Medicine, Hamamatsu, Japan, from April 2018 to August 2018. ANIMALS: Fifteen pigs, (mean ±â€ŠSD) 25.2 ±â€Š0.4 kg. INTERVENTIONS: The pigs were anaesthetised with 2.5% isoflurane and phenylephrine 0.5, 1, 2 and 5 µg kg min was administered in a stepwise fashion at 10-min intervals (baseline), followed by similar administration of sodium nitroprusside. Hypovolaemia was induced by a 600-ml bleed (33% of estimated total blood volume). Then phenylephrine was administered again (same protocol). Hypovolaemia was reversed by infusion of 600-ml hydroxyethyl starch. Phenylephrine and sodium nitroprusside were then administered again (same protocol). MAIN OUTCOME MEASURES: Average of the relation between mean arterial pressure (MAP) and cerebral or renal tissue oxygenation index (TOI) and individual TOI response during vasoactive drug infusions. RESULTS: The average relationship between MAP and cerebral or renal TOI both showed classic autoregulation patterns, whereas the renal TOI was more pressure-dependent than the cerebral TOI. Hypovolaemia shifted the relationship downward, reducing the cerebral and renal TOIs by approximately 5 and 20%, respectively, at similar MAPs. Subsequent fluid resuscitation preserved the autoregulatory pattern in both organs, not changing cerebral TOI but reducing renal TOI to 10% under baseline. TOI responses in both organs included paradoxical changes (tissue oxygenation changed inversely with MAP) in 60% of animals. Animals with paradoxical reactions maintained more stable cerebral and renal oxygenation. CONCLUSION: Renal oxygenation is more pressure-dependent than pressure-tolerant cerebral oxygenation, and autoregulation is not robust. Renal oxygenation decreased four-fold compared with cerebral oxygenation during hypovolaemia and two-fold during isovolaemic anaemia. Thus, paradoxical responses are part of normal autoregulatory function and beneficial for maintaining stable oxygenation.

Vasoreactivity to Acetylcholine During Porcine Kidney Perfusion for the Assessment of Ischemic Injury.

BACKGROUND: The effects of renal allograft ischemic injury on vascular endothelial function have not been clearly established. The aim of this study was to examine vascular reactivity to acetylcholine (ACh) in kidneys subjected to ischemic injury and reperfusion. METHODS: Porcine kidneys were exposed to different combinations of warm ischemic time (WIT) and cold ischemic time (CIT) as follows: 15 min (n = 7), 60 min (n = 6), 90 min (n = 6), or 120 min (n = 4) WIT + 2 h CIT or 15 min WIT + 16 h CIT (n = 8). Kidneys were reperfused at 38°C for 3 h. After reperfusion, ACh was infused into the circuit to assess endothelium-dependent vascular reactivity. RESULTS: The dose-response relationships between renal blood flow and ACh demonstrated that ACh doses of 10-10 to 10-7 mmol/L caused vasodilatation, whereas doses in the range 10-6 to 10-4 mmol/L led to vasoconstriction. For kidneys exposed to 15-90 min WIT, there was a clear relationship between increasing ischemic injury and reduced vasodilatation to ACh. In contrast, kidneys subjected to 120 min WIT completely lost vasoreactivity. The vasodilatory response to ACh was diminished, but not lost, when CIT was increased from 2 h to 16 h. Peak renal blood flow after ACh infusion correlated with the functional parameters in kidneys with 2 h CIT (P < 0.05). CONCLUSIONS: The loss of renal vascular reactivity after 120 min WIT suggests endothelial dysfunction leading to loss of nitric oxide synthesis/release. Measurement of vasoreactivity to ACh in an isolated organ perfusion system has the potential to be developed as a marker of ischemic renal injury before transplantation.

Multiparametric assessment of renal physiology in healthy volunteers using noninvasive magnetic resonance imaging.

Noninvasive methods of magnetic resonance imaging (MRI) can quantify parameters of kidney function. The main purpose of this study was to determine baseline values of such parameters in healthy volunteers. In 28 healthy volunteers (15 women and 13 men), arterial spin labeling to estimate regional renal perfusion, blood oxygen level-dependent transverse relaxation rate (R2*) to estimate oxygenation, and apparent diffusion coefficient (ADC), true diffusion (D), and longitudinal relaxation time (T1) to estimate tissue properties were determined bilaterally in the cortex and outer and inner medulla. Additionally, phase-contrast MRI was applied in the renal arteries to quantify total renal blood flow. The results demonstrated profound gradients of perfusion, ADC, and D with highest values in the kidney cortex and a decrease towards the inner medulla. R2* and T1 were lowest in kidney cortex and increased towards the inner medulla. Total renal blood flow correlated with body surface area, body mass index, and renal volume. Similar patterns in all investigated parameters were observed in women and men. In conclusion, noninvasive MRI provides useful tools to evaluate intrarenal differences in blood flow, perfusion, diffusion, oxygenation, and structural properties of the kidney tissue. As such, this experimental approach has the potential to advance our present understanding regarding normal physiology and the pathological processes associated with acute and chronic kidney disease.

Duplex Ultrasound Assessment and Outcomes of Renal Malperfusion Syndromes after Acute Aortic Dissection.

BACKGROUND: We investigated the feasibility of renal duplex ultrasound in the identification of renal malperfusion in acute aortic dissection and evaluated whether intervention for renal malperfusion improved outcomes over best medical management alone. METHODS: All patients with acute aortic dissections involving the renovisceral aorta who underwent a duplex ultrasound were included (2004-2016). We assessed duplex findings among patients who developed acute kidney injury (AKI; 50% increase in serum creatinine) and compared AKI, 30-day mortality, and overall survival among patients who underwent a procedure to treat malperfusion versus those who did not. RESULTS: Of 37 patients with acute dissection involving the renovisceral aorta (73% were male, 59% had type B dissection, mean follow-up 4.6 ± 0.6 years), 70% developed AKI, 11% required dialysis, and 5% developed permanent dialysis dependence. AKI was correlated with higher peak creatinine levels (4.2 vs. 2.2 mg/dL, P < 0.001), although 30-day mortality and overall survival were similar (both, P ≥ 0.24). Progression to AKI was associated with significantly lower end-diastolic velocity (EDV) measurements on renal duplex (17 vs. 27 cm/sec, P = 0.03); an EDV threshold of 23 cm/sec had a positive predictive value of 85% for AKI. Operative intervention (n = 10) was associated with lower follow-up creatinine (0.9 vs. 2.1 mg/dL, P = 0.002), although there was no difference in progression to dialysis dependence, 30-day mortality, or overall survival (all, P ≥ 0.34). CONCLUSIONS: Patients who developed AKI demonstrated characteristic renal duplex ultrasound findings with lower EDV measurements in the distal renal arteries bilaterally. Performing a renal malperfusion procedure was associated with normalization of postoperative creatinine without affecting 30-day mortality or overall survival.

Intraoperative assessment of ureteral and graft reperfusion during robotic kidney transplantation with indocyanine green fluorescence videography.

BACKGROUND: The aim of this paper is to report the first preliminary experience with intraoperative indocyanine green (ICG) fluorescence videography (IFV) to assess graft and ureteral reperfusion during robot-assisted kidney transplantation (RAKT). METHODS: We prospectively collected data from consecutive patients undergoing RAKT and IFV from living-donors at our Institution between January 2017 and April 2018. RAKT was performed following the principles of the Vattikuti-Medanta technique. ICG was injected intravenously after vascular anastomoses to quantitate graft and ureteral fluorescence signal. The signal intensity within selected intraoperative snapshots was evaluated for renal parenchyma, ureter and vascular anastomoses. A systematic review of the English-language literature about the topic was performed according to the PRISMA statement recommendations. RESULTS: Six patients were included. Neither conversions to open surgery nor major intra- or postoperative complications were recorded. At a median follow-up of 12 months (IQR 8-13), median estimated glomerular filtration rate was 64.2 mL/min/1.73 m2 (IQR 45.3-98.4). Intraoperative quantitative assessment of ICG fluorescence was successful in all patients. Of the five studies selected by our review, mostly prospective studies, all including open KT series. Yet, most studies were limited by lack of quantitative measures of IFV fluorescence. CONCLUSIONS: IFV during RAKT is feasible and safe and provides a reliable assessment of graft reperfusion. Larger studies are needed to standardize the technique and to evaluate the association between fluorescence signal, ultrasound parameters and postoperative kidney function.

[Modern radiology diagnostics methods for assessment of renal perfusion in patients with urinary stone disease].

Urinary stone disease is the current issue for healthcare system worldwide. High prevalence of urinary stone disease (at least 5% of the population of developed countries) determines clinical significance of the studying of its etiology and pathogenesis, improving of diagnostic methods and novel treatment technologies. The development of endoscopic devices, creation of new eswl machines and improvement of endourology interventions under X-ray guidance allowed to solve the problem of surgical treatment. Therefore, one of the actual issue is the choice of X-ray method for predicting and evaluating of treatment efficiency in patients with urinary stone disease. The changes of renal blood flow depend on urodynamic disturbances, stone location and size, the duration of disease, complications, patients age. Therefore, for comprehensive studying of renal function the hemodynamics evaluation is needed. In this review the advantages, drawbacks and perspective on developing of different radiologic methods for renal hemodynamic assessment are given.

Assessment of the blood flow in kidneys of growth-restricted fetuses using quantitative three-dimensional power Doppler ultrasound.

OBJECTIVE: Fetuses with fetal growth restrictions have higher perinatal mortality rates than fetuses without fetal growth restrictions. Vascularization of the fetal kidney is crucial to fetal growth. Hence, we assessed blood flow and vascularization of fetal kidneys in non-growth-restricted as well as growth-restricted fetuses using quantitative three-dimensional power Doppler ultrasound. MATERIALS AND METHODS: We undertook a prospective study to evaluate the vascular indices of fetal kidneys; i.e., the vascularization index, flow index and vascularization-flow index, in growth-restricted and non-growth-restricted fetuses using three-dimensional power Doppler ultrasound and quantitative three-dimensional histogram analysis. All fetuses from 20 to 40 weeks of gestation were singletons with a normal pregnancy and were followed up to delivery. RESULTS: In total, 209 fetuses without fetal growth restriction and 50 fetuses with fetal growth restriction were included. Our results showed the fetal renal vascularization index, flow index, and vascularization-flow index evaluated by three-dimensional power Doppler ultrasound can differentiate fetuses with fetal growth restriction from fetuses without fetal growth restriction. CONCLUSION: The fetal renal vascularization index, flow index, and vascularization-flow index measured by three-dimensional power Doppler ultrasound can be applied to prenatally detect fetal growth restriction. Our data support assessment of the fetal renal vascularization index, flow index, and vascularization-flow index using three-dimensional power Doppler ultrasound as a useful test for detecting fetuses with fetal growth restriction.