Functional evaluation of transplanted kidneys with diffusion-weighted and BOLD MR imaging: initial experience

Area of Science:

• Nephrology
• Radiology
• Biomedical Engineering

Background:

• Renal allograft recipients require non-invasive monitoring for graft function.
• Diffusion-weighted (DW) and blood oxygenation level-dependent (BOLD) magnetic resonance (MR) imaging offer potential for assessing kidney health.
• Evaluating the feasibility and reproducibility of these MR techniques in allograft recipients is crucial.

Purpose of the Study:

• To prospectively assess the feasibility and reproducibility of DW and BOLD MR imaging in renal allograft patients.
• To compare MR imaging findings in renal allografts with those in healthy native kidneys.
• To investigate the relationship between MR imaging parameters and renal function markers.

Main Methods:

• Fifteen renal allograft recipients and 15 healthy volunteers underwent DW and BOLD MR imaging.
• DW imaging provided apparent diffusion coefficient (ADC(tot), ADC(D)) and perfusion fraction.
• BOLD imaging estimated renal oxygenation via R2* measurements. Reproducibility was assessed by repeated measurements in seven patients.

Main Results:

• Apparent diffusion coefficient values were similar in the cortex and medulla of allograft recipients.
• Medullary R2* (renal oxygenation) was higher than cortical R2* in both groups but lower in patients than volunteers.
• Low coefficients of variation (<5.2%) for ADC(tot), ADC(D), and R2* indicated good reproducibility. Diffusion and perfusion indexes correlated with serum creatinine.

Conclusions:

• DW and BOLD MR imaging are feasible and reproducible methods for evaluating renal allografts.
• These MR techniques can provide insights into renal oxygenation and diffusion characteristics in transplant recipients.
• The findings suggest potential for these MR techniques in monitoring renal allograft status and function.