"While the quantitative MRI metrics included in our study have been individually validated in renal transplant patients, there have been no published test-retest repeatability studies in this patient population," said study co-author Octavia Bane, PhD, a postdoctoral research fellow at the Icahn School of Medicine at Mount Sinai. "For wider adoption of quantitative MRI parameters as quantitative biomarkers in renal transplant dysfunction, the scan-rescan repeatability of these parameters must be proved."
The researchers prospectively enrolled 11 functional renal transplants patients with a mean age of 57 years. All patients underwent 1.5-tesla MRI scans (Magnetom Aera, Siemens Healthineers) on two different days an average of 24 days apart.
The imaging protocol included intravoxel-incoherent motion diffusion-weighted imaging (IVIM-DWI), diffusion-tensor imaging (DTI), blood oxygen level-dependent (BOLD) imaging, and dynamic contrast-enhanced (DCE) MRI renography. A macrocyclic gadolinium-based contrast agent (Dotarem, Guerbet) also was administered.
Among other results, Bane and colleagues found the IVIM-DWI parameters to be highly repeatable, except for perfusion fraction and pseudodiffusion. In addition, DCE-MRI achieved acceptable repeatability for glomerular filtration rate but poorer repeatability for renal plasma flow and mean transit time. There was no statistically significant correlation between serum-estimated glomerular filtration rate and MRI parameters and between IVIM-DWI and BOLD or DCE-MRI parameters.
"Knowledge of test-retest repeatability would allow investigators to identify differences in [multiparametric MRI]-derived parameters that reflect intrinsic renal dysfunction rather than normal physiological variation and measurement noise," Bane told AuntMinnie.com. "We are currently investigating the value of [multiparametric MRI]-derived metrics for characterizing renal allograft dysfunction in a larger study."
