Feasibility of renal perfusion quantification by Fourier decomposition MRI

2021 ◽  
Author(s):  
B. Valentin ◽  
J. Stabinska ◽  
F. Reurik ◽  
C. Tell ◽  
A. Mewes ◽  
...  
Keyword(s):  
Renal Perfusion ◽  
Fourier Decomposition ◽  
Perfusion Quantification

scholarly journals Three-dimensional US Fractional Moving Blood Volume: Validation of Renal Perfusion Quantification

Radiology ◽  
2019 ◽  
Vol 293 (2) ◽  
pp. 460-468 ◽  
Author(s):  
Alec W. Welsh ◽  
J. Brian Fowlkes ◽  
Stephen Z. Pinter ◽  
Kimberly A. Ives ◽  
Gabe E. Owens ◽  
...  
Keyword(s):  
Blood Volume ◽  
Three Dimensional ◽  
Renal Perfusion ◽  
Perfusion Quantification

scholarly journals Comparison of multi-delay FAIR and pCASL labeling approaches for renal perfusion quantification at 3T MRI

2019 ◽  
Vol 33 (1) ◽  
pp. 81-94 ◽  
Author(s):  
Anita A. Harteveld ◽  
Anneloes de Boer ◽  
Suzanne Lisa Franklin ◽  
Tim Leiner ◽  
Marijn van Stralen ◽  
...  
Keyword(s):  
Blood Flow ◽  
Arterial Spin Labeling ◽  
Spin Labeling ◽  
Renal Perfusion ◽  
Intra Class Correlation ◽  
3T Mri ◽  
Perfusion Measurement ◽  
Arterial Transit Time ◽  
Perfusion Quantification ◽  
Intra Class Correlation Coefficient

Abstract Objective To compare the most commonly used labeling approaches, flow-sensitive alternating inversion recovery (FAIR) and pseudocontinuous arterial spin labeling (pCASL), for renal perfusion measurement using arterial spin labeling (ASL) MRI. Methods Multi-delay FAIR and pCASL were performed in 16 middle-aged healthy volunteers on two different occasions at 3T. Relative perfusion-weighted signal (PWS), temporal SNR (tSNR), renal blood flow (RBF), and arterial transit time (ATT) were calculated for the cortex and medulla in both kidneys. Bland–Altman plots, intra-class correlation coefficient, and within-subject coefficient of variation were used to assess reliability and agreement between measurements. Results For the first visit, RBF was 362 ± 57 and 140 ± 47 mL/min/100 g, and ATT was 0.47 ± 0.13 and 0.70 ± 0.10 s in cortex and medulla, respectively, using FAIR; RBF was 201 ± 72 and 84 ± 27 mL/min/100 g, and ATT was 0.71 ± 0.25 and 0.86 ± 0.12 s in cortex and medulla, respectively, using pCASL. For both labeling approaches, RBF and ATT values were not significantly different between visits. Overall, FAIR showed higher PWS and tSNR. Moreover, repeatability of perfusion parameters was better using FAIR. Discussion This study showed that compared to (balanced) pCASL, FAIR perfusion values were significantly higher and more comparable between visits.

Effect of Renal Perfusion Pressure on Renal Interstitial Hydrostatic Pressure and Sodium Excretion

Hypertension ◽  
1995 ◽  
Vol 25 (4) ◽  
pp. 866-871 ◽  
Author(s):  
Tetsuya Nakamura ◽  
Tetsuo Sakamaki ◽  
Toshiaki Kurashina ◽  
Kunio Sato ◽  
Zenpei Ono ◽  
...  
Keyword(s):  
Hydrostatic Pressure ◽  
Sodium Excretion ◽  
Perfusion Pressure ◽  
Renal Perfusion ◽  
Renal Perfusion Pressure

Vibration analysis and combustion parameter evaluation of CI engine based on Fourier Decomposition Method

2021 ◽  
pp. 146808742098819
Author(s):  
Wang Yang ◽  
Cheng Yong
Keyword(s):  
Vibration Analysis ◽  
Decomposition Method ◽  
Combustion Process ◽  
Pressure Rise ◽  
Maximum Pressure ◽  
Vibration Signals ◽  
Loop Control ◽  
Fourier Decomposition ◽  
Surface Vibration ◽  
Rise Rate

As a non-intrusive method for engine working condition detection, the engine surface vibration contains rich information about the combustion process and has great potential for the closed-loop control of engines. However, the measured engine surface vibration signals are usually induced by combustion as well as non-combustion excitations and are difficult to be utilized directly. To evaluate some combustion parameters from engine surface vibration, the tests were carried out on a single-cylinder diesel engine and a new method called Fourier Decomposition Method (FDM) was used to extract combustion induced vibration. Simulated and test results verified the ability of the FDM for engine vibration analysis. Based on the extracted vibration signals, the methods for identifying start of combustion, location of maximum pressure rise rate, and location of peak pressure were proposed. The cycle-by-cycle analysis of the results show that the parameters identified based on vibration and in-cylinder pressure have the similar trends, and it suggests that the proposed FDM-based methods can be used for extracting combustion induced vibrations and identifying the combustion parameters.

scholarly journals Preservation of renal endothelial integrity and reduction of renal edema by aprotinin does not preserve renal perfusion and function following experimental cardiopulmonary bypass

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Nicole A. M. Dekker ◽  
Anoek L. I. van Leeuwen ◽  
Matijs van Meurs ◽  
Jill Moser ◽  
Jeannette E. Pankras ◽  
...  
Keyword(s):  
Cardiopulmonary Bypass ◽  
Renal Injury ◽  
Weight Ratio ◽  
Kidney Injury ◽  
Dry Weight ◽  
Renal Perfusion ◽  
Plasma Creatinine ◽  
Microcirculatory Perfusion ◽  
Neutrophil Influx ◽  
Endothelial Integrity

Abstract Background Acute kidney injury is a severe complication following cardiopulmonary bypass (CPB) and is associated with capillary leakage and microcirculatory perfusion disturbances. CPB-induced thrombin release results in capillary hyperpermeability via activation of protease-activated receptor 1 (PAR1). We investigated whether aprotinin, which is thought to prevent thrombin from activating PAR1, preserves renal endothelial structure, reduces renal edema and preserves renal perfusion and reduces renal injury following CPB. Methods Rats were subjected to CPB after treatment with 33.000 KIU/kg aprotinin (n = 15) or PBS (n = 15) as control. A secondary dose of 33.000 KIU/kg aprotinin was given 60 min after initiation of CPB. Cremaster and renal microcirculatory perfusion were assessed using intravital microscopy and contrast echography before CPB and 10 and 60 min after weaning from CPB. Renal edema was determined by wet/dry weight ratio and renal endothelial structure by electron microscopy. Renal PAR1 gene and protein expression and markers of renal injury were determined. Results CPB reduced cremaster microcirculatory perfusion by 2.5-fold (15 (10–16) to 6 (2–10) perfused microvessels, p < 0.0001) and renal perfusion by 1.6-fold (202 (67–599) to 129 (31–292) au/sec, p = 0.03) in control animals. Both did not restore 60 min post-CPB. This was paralleled by increased plasma creatinine (p < 0.01), neutrophil gelatinase-associated lipocalin (NGAL; p = 0.003) and kidney injury molecule-1 (KIM-1; p < 0.01). Aprotinin treatment preserved cremaster microcirculatory perfusion following CPB (12 (7–15) vs. 6 (2–10) perfused microvessels, p = 0.002), but not renal perfusion (96 (35–313) vs. 129 (31–292) au/s, p > 0.9) compared to untreated rats. Aprotinin treatment reduced endothelial gap formation (0.5 ± 0.5 vs. 3.1 ± 1.4 gaps, p < 0.0001), kidney wet/dry weight ratio (4.6 ± 0.2 vs. 4.4 ± 0.2, p = 0.046), and fluid requirements (3.9 ± 3.3 vs. 7.5 ± 3.0 ml, p = 0.006) compared to untreated rats. In addition, aprotinin treatment reduced tubulointerstitial neutrophil influx by 1.7-fold compared to untreated rats (30.7 ± 22.1 vs. 53.2 ± 17.2 neutrophil influx/section, p = 0.009). No differences were observed in renal PAR1 expression and plasma creatinine, NGAL or KIM-1 between groups. Conclusions Aprotinin did not improve renal perfusion nor reduce renal injury during the first hour following experimental CPB despite preservation of renal endothelial integrity and reduction of renal edema.

scholarly journals FRI0177 MULTI-MODALITY IMAGING TO EVALUATE LUPUS NEPHRITIS

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 672.2-673
Author(s):  
C. Dykas ◽  
B. H. Rovin ◽  
M. Boesen ◽  
O. Kubassova ◽  
P. Lipsky
Keyword(s):  
Image Analysis ◽  
Renal Function ◽  
Rank Correlation ◽  
Renal Perfusion ◽  
Imaging Data ◽  
Spearman Rank Correlation ◽  
Dce Mri ◽  
Analysis Group ◽  
Multi Center Study ◽  
Mean Time

Background:Lupus nephritis (LN) remains a significant cause of morbidity and mortality in subjects with Systemic Lupus Erythematosus (SLE). The gold standard for evaluation of LN remains the kidney biopsy, whereas renal function is usually evaluated by eGFR and urinary protein:creatinine ratio. More effective and sensitive methodology is needed to assess LN and also the response to treatment. Functional imaging of the kidney using quantitative techniques has great potential, as it can assess kidney function and pathologic changes non-invasively by evaluating perfusion, oxygenation, cellular density and fibrosis.Objectives:The objective of this study was to develop a multi-modality imaging approach for the evaluation of the spectrum of pathologic changes in LN and to determine when imaging data correlated with renal functionMethods:In this multi-center study (NCT03180021), subjects who were having a standard of care renal biopsy for LN were asked to participate in the imaging evaluation. Local Institutional Review Board approval was obtained, and subjects signed an Informed Consent Form. Dynamic contrast enhanced MRI (DCE-MRI) was employed to detect changes in vascularization and perfusion, Diffusion Weighted Imaging (DWI) to assess interstitial diffusion, T2*Map/BOLD to evaluate tissue oxygenation and T1rho to evaluate fibrosis (Figure 1). Regions of interest were identified in the imaged kidneys and imaging parameters were correlated with measures of renal function, including eGFR and urinary protein: creatinine ratio. In DCE-MRI, we specifically focused on mean Maximum Enhancement (ME), mean Time to Peak Enhancement (TTP) and mean Time of Washout (Twashout) as indicators of renal perfusion.Results:Nine subjects have been evaluated to date and their imaging data assessed for quality. Evaluation of mean data from DCE-MRI has shown a significant correlation between renal perfusion and renal function. For example, as shown in the figure, the 24 hour protein concentration negatively correlated with ME (rs=-0.81, p=0.015), TTP (rs=-0.83, p=0.01) and Twashout (rs=-0.81.p=0.01, Spearman rank correlation). In addition, the protein:creatinine ratio also negatively correlated with ME (rs=-0.79, p=0.02), TTP (rs=-0.74, p=0.04) and Twashout (rs=-0.79, p=0.02, Spearman rank correlation).Conclusion:These initial results have established the feasibility of multi-modality imaging as a tool to evaluate LN in a multi-center study. Moreover, changes in perfusion detected by DCE-MRI significantly correlate with proteinuria and urinary protein:creatinine ratio. These results suggest that multiparameter imaging may contribute useful data in the evaluation of subjects with LN.Figure:Disclosure of Interests:Claire Dykas: None declared, Brad H Rovin Grant/research support from: GSK, Consultant of: GSK, Mikael Boesen Consultant of: AbbVie, AstraZeneca, Eli Lilly, Esaote, Glenmark, Novartis, Pfizer, UCB, Paid instructor for: IAG, Image Analysis Group, AbbVie, Eli Lilly, AstraZeneca, esaote, Glenmark, Novartis, Pfizer, UCB (scientific advisor)., Speakers bureau: Eli Lilly, Esaote, Novartis, Pfizer, UCB, Olga Kubassova Shareholder of: IAG, Image Analysis Group, Consultant of: Novartis, Takeda, Lilly, Employee of: IAG, Image Analysis Group, Peter Lipsky Consultant of: Horizon Therapeutics

Selective neuronal nitric oxide synthase inhibition blocks furosemide-stimulated renin secretion in vivo

1995 ◽  
Vol 269 (1) ◽  
pp. F134-F139 ◽  
Author(s):  
W. H. Beierwaltes
Keyword(s):  
Nitric Oxide ◽  
Blood Pressure ◽  
Nitric Oxide Synthase ◽  
Perfusion Pressure ◽  
Renal Perfusion ◽  
Macula Densa ◽  
Renin Secretion ◽  
Renal Perfusion Pressure ◽  
Neuronal Nos ◽  
Oxide Synthase

The macula densa is a regulatory site for renin. It contains exclusively the neuronal isoform of nitric oxide synthase (NOS), suggesting NO could stimulate renin secretion through the macula densa pathway. To test whether neuronal NOS mediates renin secretion, renin was stimulated by either the renal baroreceptor or the diuretic furosemide (acting through the macula densa pathway). Renin secretion rate (RSR) was measured in 12 Inactin-anesthetized rats at normal (104 +/- 3 mmHg) and reduced renal perfusion pressure (65 +/- 1 mmHg), before and after selective blockade of the neuronal NOS with 7-nitroindazole (7-NI, 50 mg/kg ip). 7-NI had no effect on basal blood pressure (102 +/- 2 mmHg) or renal blood flow (RBF). Decreasing renal perfusion pressure doubled RSR from 11.8 +/- 3.3 to 22.9 +/- 5.7 ng ANG I.h-1.min-1 (P < 0.01) (ANG I is angiotensin I). Similarly, in 7-NI-treated rats, reduced perfusion doubled RSR from 8.5 +/- 1.8 to 20.5 +/- 6.2 ng ANG I.h-1.min-1 (P < 0.01). Renal hemodynamics and RSR were measured in response to 5 mg/kg iv furosemide in 12 control rats and 11 rats treated with 7-NI. Blocking neuronal NOS did not alter blood pressure (102 +/- 2 mmHg), RBF (5.8 +/- 0.4 ml.min-1.g kidney wt-1), or renal vascular resistance (18.7 +/- 1.4 mmHg.ml-1.min.g kidney wt).(ABSTRACT TRUNCATED AT 250 WORDS)

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