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Kidney Week

Abstract: TH-PO1124

Functional MRI Defined-Renal Cortex Hypoxia Is a Proteinuria-Independent Predictor for Progression of CKD

Session Information

Category: CKD (Non-Dialysis)

  • 1902 CKD (Non-Dialysis): Clinical, Outcomes, and Trials

Authors

  • Sugiyama, Kei, Saitama Medical University, Iruma-gun, Saitama, Japan
  • Inoue, Tsutomu, Saitama Medical University, Iruma-gun, Saitama, Japan
  • Kozawa, Eito, Saitama Medical University, Iruma-gun, Saitama, Japan
  • Ishikawa, Masahiro, Saitama Medical University, Hidaka-shi, Saitama, Japan
  • Amano, Hiroaki, Saitama Medical University, Iruma-gun, Saitama, Japan
  • Shimada, Akira, Saitama Medical University, Saitama, Japan
  • Kobayashi, Naoki, Saitama Medical University, Hidaka-shi, Saitama, Japan
  • Tanaka, Junji, Saitama Medical University, Iruma-gun, Saitama, Japan
  • Okada, Hirokazu, Saitama Medical University, Iruma-gun, Saitama, Japan
Background

Progression of chronic kidney disease (CKD) is characterized by tubulointerstitial fibrosis and glomerulosclerosis. Chronic hypoxia followed by inflammation may be key to this process. Until now, however, there has been no means of evaluating this noninvasively. Here, we employed blood oxygen level-dependent (BOLD) and diffusion-weighted (DW) magnetic resonance imaging (MRI) to assess renal tissue oxygenation and fibrosis, respectively, and evaluated their correlation with clinical parameters in a single-center, longitudinal, retrospective observational study over five years.

Methods

We examined the prognostic significance of the T2* values of BOLD MRI and apparent diffusion coefficient (ADC) values on DW MRI at the cortex and medulla as well as diabetes mellitus, mean blood pressure, estimated glomerular filtration rate, serum urate levels, and proteinuria. Rate of decline in eGFR was calculated by linear regression analysis using changes in estimated glomerular filtration rate (eGFR) during the observation period. MRI was performed with a 1.5 T Imager (Sonata®; Siemens, Erlangen, Germany) and a six-channel body coil. Both T2* and ADC maps were generated using software in the MRI scanner.

Results

A total of 91 patients were enrolled. Participants, male = 51 (56.0%), were aged 55.8 ± 15.6 years. Thirty-eight (41.8%) had diabetes mellitus, and the eGFR was 49.2 ± 28.9 mL/min/1.73 m2 at the time of enrollment. ADC values, but not T2* values, of renal cortex were well correlated with eGFR at the start point. Neither the ADC nor T2* values of the renal medulla showed significant correlation with clinical parameters due to large variations. The rate decline in eGFR per year (ΔGFR) during the observation period was -1.92 ± 3.00 mL/min/1.73 m2. Multiple linear regression analysis revealed that ΔGFR was significantly correlated with eGFR at the start point, the amount of proteinuria, and the T2* values (t=2.980, p=0.004), but not with the ADC values.

Conclusion

Hypoxia as determined by low T2* values using functional MRI is a clinically valuable parameter that affords a proteinuria-independent predictor of CKD progression.

Funding

  • Private Foundation Support