Diffusion-weighted magnetic resonance imaging in the evaluation of renal function: a preliminary study

Area of Science:

• Radiology
• Nephrology
• Medical Imaging

Background:

• Magnetic resonance diffusion-weighted imaging (MR-DWI) assesses proton motion via apparent diffusion coefficient (ADC) calculations.
• ADC may indicate renal damage, particularly in unilateral kidney dysfunction.
• Chronic renal failure (CRF) staging requires reliable functional markers.

Purpose of the Study:

• To evaluate the correlation between ADC values and the stage of CRF.
• To assess the feasibility of MR-DWI using a spin-echo echo-planar imaging (SE-EPI) sequence with sensitivity encoding (SENSE) for renal assessment.

Main Methods:

• Fourteen patients with varying degrees of kidney function and five controls underwent MR imaging on a 1.5-T system.
• Glomerular filtration rate (GFR) was determined using the Cockcroft-Gault equation.
• A SE-EPI sequence with a diffusion gradient (600 s/mm²) and SENSE factor 2 was employed for ADC map reconstruction. Some patients received furosemide to assess dynamic changes.

Main Results:

• ADC values were significantly lower in subjects with altered GFR (2.05±0.33 x 10⁻³ mm²/s) compared to those with normal GFR (2.44±0.24 x 10⁻³ mm²/s) (p<0.05).
• A significant difference in ADC was observed between stages III and IV CRF (p<0.01), but not between earlier stages.
• A strong positive correlation was found between GFR and ADC (r=0.79; p<0.01). Furosemide administration did not significantly alter ADC values.

Conclusions:

• MR-DWI is a feasible technique for evaluating renal damage in the context of CRF.
• ADC measurements show a significant correlation with GFR, suggesting potential as a biomarker for CRF staging.
• Further research, including scintigraphic correlation, is recommended to validate these findings and establish reference ADC values for renal assessment.