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

Cantow, Kathleen; Evans, Roger G.; Grosenick, Dirk; Gladytz, Thomas; Niendorf, Thoralf; Flemming, Bert; Seeliger, Erdmann

doi:10.1007/978-1-0716-0978-1_6

Cited by 6 publications

(23 citation statements)

References 76 publications

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“…Urethane provides long‐lasting anesthesia and has the least effects on cardiovascular and respiratory control compared to other anesthetics 49 . Preparation included insertion of vascular catheters and probes for measurements of hemodynamics and oxygenation 41,46,53,74 . In a subgroup ( n = 13), two MR‐safe remotely controlled inflatable occluders were applied around the suprarenal aorta and the left renal vein 45–47 .…”

Section: Methodsmentioning

confidence: 99%

“…49 Preparation included insertion of vascular catheters and probes for measurements of hemodynamics and oxygenation. 41,46,53,74 In a subgroup (n = 13), two MR-safe remotely controlled inflatable occluders were applied around the suprarenal aorta and the left renal vein. [45][46][47] Thereafter, rats were transferred into the MR scanner.…”

Section: Animal Preparationmentioning

confidence: 99%

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Monitoring kidney size to interpret MRI‐based assessment of renal oxygenation in acute pathophysiological scenarios

et al. 2022

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Aim: Tissue hypoxia is an early key feature of acute kidney injury. Assessment of renal oxygenation using magnetic resonance imaging (MRI) markers T 2 and T 2 * enables insights into renal pathophysiology. This assessment can be confounded by changes in the blood and tubular volume fractions, occurring upon pathological insults. These changes are mirrored by changes in kidney size (KS). Here, we used dynamic MRI to monitor KS for physiological interpretation of T 2 * and T 2 changes in acute pathophysiological scenarios. Methods: KS was determined from T 2 *, T 2 mapping in rats. Six interventions that acutely alter renal tissue oxygenation were performed directly within the scanner, including interventions that change the blood and/or tubular volume. A biophysical model was used to estimate changes in O 2 saturation of hemoglobin from changes in T 2 * and KS.Results: Upon aortic occlusion KS decreased; this correlated with a decrease in T 2 *, T 2 . Upon renal vein occlusion KS increased; this negatively correlated with a decrease in T 2 *, T 2 . Upon simultaneous occlusion of both vessels KS remained unchanged; there was no correlation with decreased T 2 *, T 2 . Hypoxemia induced mild reductions in KS and T 2 *, T 2 . Administration of an X-ray contrast medium induced sustained KS increase, with an initial increase in T 2 *, T 2 followed by a decrease. Furosemide caused T 2 *, T 2 elevation and a minor increase in KS. Model calculations yielded physiologically plausible calibration ratios for T 2 *. Conclusion: Monitoring KS allows physiological interpretation of acute renal oxygenation changes obtained by T 2 *, T 2 . KS monitoring should accompany MRIoximetry, for new insights into renal pathophysiology and swift translation into human studies.

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Section: Methodsmentioning

confidence: 99%

Section: Animal Preparationmentioning

confidence: 99%

Monitoring kidney size to interpret MRI‐based assessment of renal oxygenation in acute pathophysiological scenarios

et al. 2022

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“…For anaesthesia, urethane (0.2 g/mL in distilled water; 6 mL/kg BM intraperitoneal; Sigma‐Aldrich, Steinheim, Germany) was used throughout the surgical preparation and the examination. Surgical preparation included insertion of vascular catheters and invasive probes for quantitative measurements of renal haemodynamics and oxygenation as previously described in detail 46,52,53,60,61 …”

Section: Methodsmentioning

confidence: 99%

“…Surgical preparation included insertion of vascular catheters and invasive probes for quantitative measurements of renal haemodynamics and oxygenation as previously described in detail. 46,52,53,60,61 Four rat models were employed:…”

Section: Gladytz Et Almentioning

confidence: 99%

Reliable kidney size determination by magnetic resonance imaging in pathophysiological settings

et al. 2021

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Aim Kidney diseases constitute a major health challenge, which requires noninvasive imaging to complement conventional approaches to diagnosis and monitoring. Several renal pathologies are associated with changes in kidney size, offering an opportunity for magnetic resonance imaging (MRI) biomarkers of disease. This work uses dynamic MRI and an automated bean‐shaped model (ABSM) for longitudinal quantification of pathophysiologically relevant changes in kidney size. Methods A geometry‐based ABSM was developed for kidney size measurements in rats using parametric MRI (T2, T2* mapping). The ABSM approach was applied to longitudinal renal size quantification using occlusion of the (a) suprarenal aorta or (b) the renal vein, (c) increase in renal pelvis and intratubular pressure and (d) injection of an X‐ray contrast medium into the thoracic aorta to induce pathophysiologically relevant changes in kidney size. Results The ABSM yielded renal size measurements with accuracy and precision equivalent to the manual segmentation, with >70‐fold time savings. The automated method could detect a ~7% reduction (aortic occlusion) and a ~5%, a ~2% and a ~6% increase in kidney size (venous occlusion, pelvis and intratubular pressure increase and injection of X‐ray contrast medium, respectively). These measurements were not affected by reduced image quality following administration of ferumoxytol. Conclusion Dynamic MRI in conjunction with renal segmentation using an ABSM supports longitudinal quantification of changes in kidney size in pathophysiologically relevant experimental setups mimicking realistic clinical scenarios. This can potentially be instrumental for developing MRI‐based diagnostic tools for various kidney disorders and for gaining new insight into mechanisms of renal pathophysiology.

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“…Following the first successful kidney transplantation in China in the 1960s, kidney transplantation has become a well-established method for the end-stage treatment of patients with chronic renal failure and uremia ( 1 ). Recently, the development of immunology, the use of immunosuppressants, and the improvement of surgical protocols have significantly improved the survival and quality of life of kidney transplant patients ( 2 ). Kidney transplantation in China has now entered a new phase, and under the current laws and regulations in China, donor organ donation after the death of a citizen and living organ donation by relatives have become the main sources of kidney transplantation organs.…”

Section: Introductionmentioning

confidence: 99%

A clinical study of using ROC to compare the efficiency of ASL and BOLD in diagnosis of renal allograft function

Jin¹,

Yang²,

Zhu³

et al. 2023

Transl Androl Urol

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Background: This retrospective study aims to evaluate the effectiveness of renal transplantation function by comparing arterial spin labeling (ASL) and blood oxygen level dependent (BOLD) imaging with the receiver operating characteristic (ROC) curve.Methods: According to the estimated glomerular filtration rate (eGFR) values, 42 patients with normal kidney grafts (the normal kidney graft group, eGFR <60 mL/min/1.73 m 2 ) and 93 patients with injured grafts (the kidney graft injury group, eGFR <60 mL/min/1.73 m 2 ) were included in the present study. Renal blood flow (RBF) and the effective transverse relaxation rate (R2*) were calculated by comparing ASL and BOLD imaging. The ROC curve and the youden index were used to evaluate the diagnostic performance of ASL, BOLD, and the combination of them. Results:The results showed that all the clinical features of the patients, except for gender, differed significantly between the 2 groups (P<0.05). The mean RBF value of the renal transplant injury group (104.33±54.76 mL/100 g/min) was significantly lower than that of the normal group (191.84±63.96 mL/ 100 g/min, P<0.01). The mean medullary R2* value of the renal transplant injury group (27.91±3.35 1/s) was significantly higher than that of the normal group (25.22±2.94 1/s, P<0.01). Negative correlations were found between R2* and eGFR (r=-0.44), and RBF and R2* (r=-0.54; both P<0.01). The ROC analysis showed that both RBF and R2* reflected injured renal function [area under the curves (AUC) =0.86 and 0.72, respectively]. In addition, the AUC of RBF and R2* combined was 0.86, which was comparable to that of RBF alone (P=0.95), while combining R2* and RBF improved the diagnostic performance of R2* alone (AUC =0.86 versus 0.72, respectively; P<0.01). The youden index analysis showed that the diagnostic accuracy of ASL was 80.00%, better than 71.85% of BOLD; the sensitivity and specificity of ASL in diagnosing renal allograft dysfunction were 79.57% and 80.95%, superior to 77.42% and 59.52% of BOLD.Conclusions: Our results showed that the non-invasive assessment of ASL in clinical kidney transplant function is a more promising imaging technique than BOLD.

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

Cited by 6 publications

References 76 publications

Monitoring kidney size to interpret MRI‐based assessment of renal oxygenation in acute pathophysiological scenarios

Monitoring kidney size to interpret MRI‐based assessment of renal oxygenation in acute pathophysiological scenarios

Reliable kidney size determination by magnetic resonance imaging in pathophysiological settings

A clinical study of using ROC to compare the efficiency of ASL and BOLD in diagnosis of renal allograft function

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