Consistency of Multiple Renal Functional MRI Measurements Over 18 Months

Area of Science:

• Medical Imaging
• Nephrology
• Biomedical Engineering

Background:

• Identifying patients with progressive chronic kidney disease (CKD) and predicting therapeutic response is crucial.
• Functional MRI (fMRI) shows promise for assessing CKD, but measurement consistency is vital for longitudinal studies.

Purpose of the Study:

• To evaluate the consistency of repeated functional MRI measurements in healthy individuals over an 18-month period.
• To establish the reliability of fMRI parameters for potential use in monitoring CKD progression.

Main Methods:

• A prospective, longitudinal study involving 17 healthy subjects examined 18 months apart.
• Utilized multiple MRI sequences (True-FISP, spin-echo planar diffusion-weighted) on a 3T scanner with different configurations.
• Analyzed Blood Oxygenation Level-Dependent (BOLD) R2*, arterial spin labeling (ASL) perfusion-derived blood flow (BF), and apparent diffusion coefficient (ADC) maps using custom software and defined regions of interest.

Main Results:

• Intrasubject coefficients of variation (CV) for R2* and ADC were low (6.8% and 5.3%) with minimal bias (-3.8% and 5.3%).
• Renal cortex BF showed higher intrasubject CV (18.7%) but was comparable to previous literature, with a larger bias (-15.4%) and a significant decrease at 18 months (P=0.022).

Conclusions:

• Functional MRI parameters (R2*, ADC, BF) demonstrated good consistency over 18 months, despite scanner upgrades and multiple observers.
• These findings support the use of fMRI for reliable longitudinal monitoring of CKD progression in patients.