Kidney Week

Abstract: SA-PO1142

Patterns of Low-Frequency Physiological Fluctuations in the Human Kidney Detected by Resting-State Magnetic Resonance Imaging

Session Information

• CKD: Patient-Oriented Care and Case Reports
  October 26, 2024 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: CKD (Non-Dialysis)

• 2302 CKD (Non-Dialysis): Clinical, Outcomes, and Trials

Authors

• Baldelomar, Edwin, Washington University in St Louis School of Medicine, St Louis, Missouri, United States

Edwin Baldelomar

• Eldeniz, Cihat, Washington University in St Louis School of Medicine, St Louis, Missouri, United States

Cihat Eldeniz, PhD

• Charlton, Jennifer R., University of Virginia School of Medicine, Charlottesville, Virginia, United States

Jennifer R. Charlton, MD, MS

• Bennett, Kevin M., Washington University in St Louis School of Medicine, St Louis, Missouri, United States

Kevin M. Bennett, PhD

Background

Many mechanisms in the kidney, including autoregulation, act as feedback systems and cause natural fluctuations in perfusion. Detecting these spontaneous hemodynamic fluctuations could provide patient-specific signatures of early disease progression. Non-contrast resting-state magnetic resonance imaging (rsMRI) was recently developed to detect spontaneous physiological fluctuations in the human kidney, in vivo. Here, we examined the spatial patterns and reproducibility of these measured fluctuations.

Methods

We performed rsMRI at 3T over 10 minutes (gradient echo, TE/TR=2.27/4.2ms, resolution=2.5mm³, temporal resolution = 0.605sec) of the kidneys of two healthy subjects (1 male, 1 female, ages 46-47, no reported history of kidney disease). Individuals were imaged twice on the same day, and again ~16 months later. Imaging and image processing were performed using published protocols.

Results

rsMRI demonstrated spontaneous physiological fluctuations throughout the human kidney (Figure 1A-D). Strong fluctuations at ~0.03Hz occurred in the cortex in 60.5±13.6% of voxels (Figure 1B). Specific fluctuations appeared in other tissue compartments: e.g. vessels, 0.1-0.2Hz; ureter, ~0.05 Hz (Figure 1C-D). rsMRI spectra from cortex and medulla exhibited characteristic peaks in frequency ranges of 0.015-0.026, 0.027-0.038, 0.039-0.05 Hz (Figure 1,E-G). Characteristic spectra were reproducible between scans and over 16 months (77.8% in the male and 88.9% in the female kidney).

Conclusion

rsMRI can be used to map spontaneous hemodynamic fluctuations at frequencies in the healthy human adult kidney. Patterns of these fluctuations are specific to individual subjects and are reproducible over 16 months. rsMRI may detect physiological biomarkers that reflect disease progression or response to therapies.

Funding

• NIDDK Support