Renal BOLD-MRI does not reflect renal function in chronic kidney disease

Area of Science:

• Medical Imaging
• Nephrology
• Biophysics

Background:

• Renal blood oxygen level-dependent magnetic resonance imaging (BOLD-MRI) offers a noninvasive method for assessing kidney function.
• Characterizing renal function via BOLD-MRI requires understanding relaxation rate (R2(*)) variations in the renal cortex and medulla.

Purpose of the Study:

• To evaluate the impact of renal function on R2(*) in the renal cortex and medulla.
• To establish baseline data for the clinical application of renal BOLD-MRI.
• To determine if BOLD-MRI can differentiate between stages of chronic kidney disease (CKD).

Main Methods:

• Renal BOLD-MRI was performed on 400 patients using a multi-echo gradient-echo sequence.
• Loss of phase coherence (T2(*)) maps were generated, and R2(*) was calculated as 1/T2(*).
• R2(*) values were correlated with estimated glomerular filtration rate (eGFR), age, and gender at 1.5T and 3.0T field strengths.

Main Results:

• No significant differences in R2(*) were observed between genders, age groups, or eGFR levels.
• BOLD-MRI R2(*) values did not significantly differ across various stages of chronic kidney disease (CKD) as defined by KDOQI staging.
• The study failed to demonstrate discrimination between CKD stages using BOLD-MRI in a non-specific patient population.

Conclusions:

• Renal BOLD-MRI, in its current application to a general patient cohort, is not sufficiently sensitive to differentiate between varying stages of chronic kidney disease.
• Further research is needed to refine BOLD-MRI techniques for specific diagnostic applications in nephrology.