Detection of Renal Hypoxia Configuration in Patients with Lupus Nephritis: A Primary Study Using Blood Oxygen Level‒Dependent MR Imaging

Abstract

Background Renal microstructure and function are closely associated with homeostasis of oxygenation. Analyzing renal blood oxygen level‒dependent (BOLD) magnetic resonance imaging (MRI) examination results will provide information on the biological status of the kidneys. The current study was performed to explore the hypoxia mode of the entire renal parenchyma in patients with lupus nephritis (LN). Methods Twenty-three adult patients with LN and eighteen healthy volunteers were recruited. R2* values were acquired through the use of the BOLD MRI analysis technique. The narrow rectangular region of interest was used to explore the hypoxia configuration in entire depths of renal parenchyma. Acquired sequential R2* data were fitted by using four categories of mathematic functions. The tendency of R2* data in both patients with LN and healthy volunteers was also compared through the use of repeated-measures analysis of variance. Results R2* data from the superficial cortex to deep medulla displayed two patterns, called a sharp uptrend style and a flat uptrend style. After sequential R2* data were fitted individually with the use of four mathematic formulas, the multiple-compartment Gaussian function showed the highest goodness of fit. Compared with two categories of R2* value styles, the R2* tendency of entire parenchyma in patients with LN was different from that in healthy volunteers. Conclusions Deep renal medullary oxygenation was not always overtly lower than oxygenation in superficial renal cortical zone. Renal parenchyma oxygenation manifestation could be described through the use of a Gaussian function model. The deoxygenation tolerance capability was damaged in patients with LN.