Dataset Information

Quantitative Blood Oxygenation Level Dependent Magnetic Resonance Imaging for Estimating Intra-renal Oxygen Availability Demonstrates Kidneys Are Hypoxemic in Human CKD.

ABSTRACT:

Introduction

Kidney blood oxygenation level dependent (BOLD) magnetic resonance imaging (MRI) has shown great promise in evaluating relative oxygen availability. This method is quite efficacious in evaluating acute responses to physiological and pharmacologic maneuvers. Its outcome parameter, R2∗ is defined as the apparent spin-spin relaxation rate measured in the presence of magnetic susceptibility differences and it is measured using gradient echo MRI. Although associations between R2∗ and renal function decline have been described, it remains uncertain to what extent R2∗ is a true reflection of tissue oxygenation. This is primarily because of not taking into account the confounding factors, especially fractional blood volume (fBV) in tissue.

Methods

This case-control study included 7 healthy controls and 6 patients with diabetes and chronic kidney disease (CKD). Using data before and after administration of ferumoxytol, a blood pool MRI contrast media, the fBVs in kidney cortex and medulla were measured.

Results

This pilot study independently measured fBV in kidney cortex (0.23 ± 0.03 vs. 0.17 ± 0.03) and medulla (0.36 ± 0.08 vs. 0.25 ± 0.03) in a small number of healthy controls (n = 7) versus CKD (n = 6). These were then combined with BOLD MRI measurements to estimate oxygen saturation of hemoglobin (StO₂) (0.87 ± 0.03 vs. 0.72 ± 0.10 in cortex; 0.82 ± 0.05 vs. 0.72 ± 0.06 in medulla) and partial pressure of oxygen in blood (bloodPO₂) (55.4 ± 6.5 vs. 38.4 ± 7.6 mm Hg in cortex; 48.4 ± 6.2 vs. 38.1 ± 4.5 mm Hg in medulla) in control versus CKD. The results for the first time demonstrate that cortex is normoxemic in controls and moderately hypoxemic in CKD. In the medulla, it is mildly hypoxemic in controls and moderately hypoxemic in CKD. Whereas fBV, StO₂, and bloodPO₂ were strongly associated with estimated glomerular filtration rate (eGFR), R2∗ was not.

Conclusion

Our results support the feasibility of quantitatively assessing oxygen availability using noninvasive quantitative BOLD MRI that could be translated to the clinic.

SUBMITTER: Prasad PV

PROVIDER: S-EPMC10166744 | biostudies-literature | 2023 May

REPOSITORIES: biostudies-literature

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Quantitative Blood Oxygenation Level Dependent Magnetic Resonance Imaging for Estimating Intra-renal Oxygen Availability Demonstrates Kidneys Are Hypoxemic in Human CKD.

Prasad Pottumarthi V PV Li Lu-Ping LP Hack Bradley B Leloudas Nondas N Sprague Stuart M SM

Kidney international reports 20230307 5

<h4>Introduction</h4>Kidney blood oxygenation level dependent (BOLD) magnetic resonance imaging (MRI) has shown great promise in evaluating relative oxygen availability. This method is quite efficacious in evaluating acute responses to physiological and pharmacologic maneuvers. Its outcome parameter, R2∗ is defined as the apparent spin-spin relaxation rate measured in the presence of magnetic susceptibility differences and it is measured using gradient echo MRI. Although associations between R2∗ ...[more]

PMID: 37180507

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Project description:Importance:Oxygenation index (OI), an invasive measurement, is routinely used as a marker of severity of hypoxemic respiratory failure in neonates. Oxygen saturation index (OSI) is a noninvasive measurement and has been shown to be a reliable surrogate marker of OI in children and adults with respiratory failure. Objectives:To evaluate the correlation of OI with OSI and to derive and validate predictive OI from noninvasive OSI measurements for clinically relevant OI values. Design, Setting, and Participants:For this retrospective cohort study, 220 neonates requiring invasive mechanical ventilation for hypoxic respiratory failure during the first 3 days of admission were recruited from a level III neonatal intensive care unit during a 6-year period, from January 1, 2012, to December 31, 2017. Data were analyzed from January 2017 to December 2017. Main Outcomes and Measures:The primary outcome was correlation of OI with OSI, analyzed using Pearson correlation coefficient. The secondary outcome was derivation and validation of OI from OSI. The data were split into derivative samples, from which a predictive equation for OI was derived using generalized linear model, and a validation sample was used to assess the predictive ability of the derived OI. Bland-Altman plot was used to assess agreement between derived OI and measured OI. Results:A total of 1442 paired OI and OSI measurements from 220 infants (190 preterm and 30 term; median [interquartile range] gestational age, 29 [26-33] weeks; mean [SD] birth weight, 1602 [1092] g) were recorded during the study. The median (interquartile range) number of samples was 5 (3-9) per patient. Overall, OI and OSI showed strong correlation (r = 0.89). The correlation was stronger in preterm infants (<28 weeks, r = 0.93; 28-33 weeks, r = 0.93) and within an oxygen saturation range of 85% to 95% (r = 0.94). The predictive derivative equation showed a strong linear association and good agreement in both derivation and validation data sets, with strong accuracy measures of derived OI for OI cutoffs of 5, 10, 15, 20, and 25. Conclusions and Relevance:A strong correlation of OI with OSI was found. Derived OI from OSI was in good agreement and strongly predictive of clinically relevant OI cutoffs from 5 to 25. Oxygenation index derived from noninvasive sources may be useful to reliably assess severity of respiratory failure and response to therapy on a continuous basis.

Project description:Rationale & objectiveThe KDIGO (Kidney Disease: Improving Global Outcomes) guideline for chronic kidney disease (CKD) presented an international classification system that ranks patients' risk for CKD progression. Few data for children informed guideline development.Study designObservational cohort study.Settings & participantsChildren aged 1 to 18 years enrolled in the North American Chronic Kidney Disease in Children (CKiD) cohort study and the European Effect of Strict Blood Pressure Control and ACE Inhibition on the Progression of CRF in Pediatric Patients (ESCAPE) trial.PredictorLevel of estimated glomerular filtration rate (eGFR) and proteinuria (urine protein-creatinine ratio [UPCR]) at study entry.OutcomeA composite event of renal replacement therapy, 50% reduction in eGFR, or eGFR<15mL/min/1.73m2. eGFR was estimated using the CKiD-derived "bedside" equation.Analytical approachAccelerated failure time models of the composite outcome using a conventional generalized gamma distribution. Likelihood ratio statistics of nested models were used to amalgamate levels of similar risk.ResultsAmong 1,232 children, median age was 12 (IQR, 8-15) years, median eGFR was 47 (IQR, 33-62) mL/min/1.73m2, 60% were males, and 13% had UPCRs>2.0mg/mg at study entry. 6 ordered stages with varying combinations of eGFR categories (60-89, 45-59, 30-44, and 15-29mL/min/1.73m2) and UPCR categories (<0.5, 0.5-2.0, and >2.0mg/mg) described the risk continuum. Median times to event ranged from longer than 10 years for eGFRs of 45 to 90mL/min/1.73m2 and UPCRs<0.5mg/mg to 0.8 years for eGFRs of 15 to 30mL/min/1.73m2 and UPCRs>2mg/mg. Children with glomerular disease were estimated to have a 43% shorter time to event than children with nonglomerular disease. Cross-validation demonstrated risk patterns that were consistent across the 10 subsample validation models.LimitationsObservational study, used cross-validation rather than external validation.ConclusionsCKD staged by level of eGFR and proteinuria characterizes the timeline of progression and can guide management strategies in children.

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Dataset Information

Quantitative Blood Oxygenation Level Dependent Magnetic Resonance Imaging for Estimating Intra-renal Oxygen Availability Demonstrates Kidneys Are Hypoxemic in Human CKD.

Introduction

Methods

Results

Conclusion

Publications

Quantitative Blood Oxygenation Level Dependent Magnetic Resonance Imaging for Estimating Intra-renal Oxygen Availability Demonstrates Kidneys Are Hypoxemic in Human CKD.

Similar Datasets

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