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Radionuclide Examination of the Kidneys
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
In routine clinical practice, absolute renal function is estimated from scintigraphic data without blood sampling by regression and model-based methods (Figure 12.11). Regression methods are derived from comparisons of radiopharmaceutical plasma clearance (dependent variable) and (background and attenuation corrected) activity accumulated in the kidneys (independent variable). The first gamma-camera regression methods for effective renal plasma flow and glomerular filtration tracers were introduced by Schlegel and Hamway [125], and by Gates [126, 127]. Despite subsequent criticism, based on common experience, that they are well reproducible but not accurate [79, 128–131], these methods and their modifications are still part of commercial nuclear medicine software. Later, more advanced studies such as those by Inoue and colleagues with DTPA [113, 132], and by Taylor and colleagues with MAG3 [133] independently resulted in similar regression equations validated in several centres [112, 134, 135].
Tubular Function
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
PAH is filtered at the glomerulus, and any remaining in the peritubular capillaries is secreted into the lumen by proximal tubules. When the PAH concentration is low, all the plasma-perfusing, -filtering and -secreting parts of the kidney (the effective renal plasma flow is 85%–90% of the total renal plasma flow) are completely cleared of PAH. The renal clearance of PAH is therefore equal to the effective renal plasma flow, from which the effective renal blood flow can be calculated:
Radiotracers For Nonimaging Studies: II
Published in Garimella V. S. Rayudu, Lelio G. Colombetti, Radiotracers for Medical Applications, 2019
L. Rao Chervu, Shanta Chervu, M. Donald Blaufox
Clinical studies of renal function and renal blood flow for the last 20 years have had a broad application. An assessment of renal function by clearance measurements using radionuclide techniques can provide the glomerular filtration rate or effective renal plasma flow. Methods for individual renal function are still in an evolving stage but a great deal of work and progress has occurred in this area.
Advances in imaging techniques to assess kidney fibrosis
Published in Renal Failure, 2023
Buchun Jiang, Fei Liu, Haidong Fu, Jianhua Mao
The application of BOLD-MRI in patients with renal fibrosis is limited but has more satisfying results than in patients with CKD. Inoue et al. used DWI and BOLD-MRI to assess renal fibrosis and hypoxia of the cortex in patients with diabetic nephropathy, non-diabetic CKD, and acute kidney injury. Consistent with the results of animal UUO models, it was suggested that the values of ADC and T2* were negatively correlated with the fibrotic area [26]. A recent study on BOLD-MRI in kidney allografts found that the cortical R2* values were positively associated with interstitial fibrosis in patients with allograft injury [27]. The different results of BOLD-MRI in CKD suggest that the R2* or T2*values are susceptible. The effective renal plasma flow and oxygen consumption caused by different renal diseases may influence the accuracy of BOLD-MRI. As studies related to renal fibrosis are limited, the potential of BOLD-MRI in assessing renal fibrosis remains to be elucidated.
Renoprotective effect of local sildenafil administration in renal ischaemia–reperfusion injury: A randomised controlled canine study
Published in Arab Journal of Urology, 2019
Mohamed H. Zahran, Nashwa Barakat, Shery Khater, Amira Awadalla, Ahmed Mosbah, Adel Nabeeh, Abdelaziz M. Hussein, Ahmed A. Shokeir
We investigated the role of sildenafil in renal protection by assessing renal function changes. Serum creatinine and BUN are rough methods to estimate renal function. So, we assessed changes in GFR for better evaluation of renal function and consolidated our present results by histopathological examination of renal tissue. Administration of sildenafil significantly improved renal function indices in comparison to the control groups. The new finding in the present study is that LS intra-arterial administration showed better renal function than its systemic administration throughout the whole study and reached statistical significance in the first 7 days after renal IR injury. This is similar to other reports that solitary kidney function can be recovered to basal levels after 1 week of the onset of ischaemia. Also, compensatory renal growth and effective renal plasma flow of the solitary kidney is restored completely after 1 week [17].
Insufficiency of the zona glomerulosa of the adrenal cortex and progressive kidney insufficiency following unilateral adrenalectomy – case report and discussion
Published in Blood Pressure, 2018
Joanna Kanarek-Kucner, Adrian Stefański, Rufus Barraclough, Tomasz Gorycki, Jacek Wolf, Krzysztof Narkiewicz, Michał Hoffmann
In another study comparing EH and PA, with the exception of increased urinary β-2-microglobulin and albumin excretion among PA patients, the two groups did not significantly differ with regard to kidney function and BP. In patients with PA treated with UA reduction in eGFR was inversely correlated with baseline eGFR and glomerular hydrostatic pressure and directly correlated with a reduction in effective renal plasma flow (eRPF), but not with BP values. Multiple factor analysis found that baseline eGFR, potassium, and the degree of postoperative reduction in eRPF all contributed to changes in eGFR. Through detailed analysis of renal blood flow, they found that patients with PA had, at baseline, lower resistance in their afferent glomerular vessels and higher glomerular hydrostatic pressures compared to patients with EH. After treatment, a significant reduction in afferent vessel resistance was found in both groups, as was a decrease in glomerular hydrostatic pressure following UA [10].