Work

Renal Metabolic Rate of Oxygen in Response to Hypoxia Challenges by Means of Quantitative MRI in Humans

Year: 2025

Type: article

Abstract: ABSTRACT In early kidney disease, tissue hypoxia occurs due to an imbalance between ATP supply and demand. Whole‐organ renal metabolic rate of oxygen (rMRO 2 ) is therefore a potential biomarker for assessing renal function. This study evaluated the sensitivity of a quantitative MRI method to detect within‐subject changes in metabolic parameters during hypoxic gas challenges. Ten healthy adults were imaged at 3 T (5 female, ages 23–53 years) while undergoing mild and moderate hypoxia (P ET O 2 62 and 52 mmHg, respectively). The utilized MRI sequence simultaneously quantified blood flow rate (BFR) and venous oxygen saturation (SvO 2 ) at the left renal vein, yielding, together with arterial oxygen saturation (SaO 2 ) obtained by pulse oximetry, whole‐organ rMRO 2 by invoking Fick's Principle. Repeated‐measures ANOVA was used to test differences in metabolic parameters between baseline and hypoxic conditions. SaO 2 at baseline was 99% ± 1%, while renal SvO 2 was 92% ± 3%. During progressive hypoxemia, the drop in SvO 2 (mild 83% ± 4%, moderate 76% ± 5%, p < 0.01) paralleled the drop in SaO 2 (mild 90% ± 1%, moderate 84% ± 2%), such that the arteriovenous difference in oxygenation (AVDO 2 ) was constant when compared to baseline ( p = 1). Renal BFR did not vary significantly between baseline (410 ± 65 mL/min) and hypoxemic conditions (mild, moderate of 430 ± 56 and 440 ± 48 mL/min, p > 0.34). Thus, rMRO 2 did not significantly change during hypoxemia (baseline, mild, and moderate of 140 ± 50, 180 ± 80, and 170 ± 90 (μmol O 2 /min)/100 g, respectively, p = 1). In conclusion, the results demonstrate the method's sensitivity in detecting within‐subject changes in metabolic parameters in response to graded hypoxia. Quantitative MRI oximetry may be a feasible tool to assess and longitudinally monitor early metabolic changes in kidney disease.

Source: NMR in Biomedicine

DOI: 10.1002/nbm.70178

Authors: Nada Kamona, Mahdie Hosseini, Michael C. Langham, Felix W. Wehrli

Institution: University of Pennsylvania

Language: English

Topic: Advanced MRI Techniques and Applications

Subfield: Radiology, Nuclear Medicine and Imaging

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: hybrid

Estimated APC paid: $3,640