Intravoxel incoherent motion imaging in monitoring the function of kidney allograft

Abstract

Background Non-invasive alternatives to percutaneous renal biopsy are sought for follow-up of renal allografts. Purpose To evaluate the feasibility of intravoxel incoherent motion (IVIM) imaging in monitoring and predicting the function of renal allografts. Material and Methods Thirty-five kidney recipients were examined on a 1.5-T MR unit approximately three and 18 months after transplantation. Based on estimated glomerular filtration rate (eGFR), patients were divided into three groups: improved; declined; and stable graft function. Diffusion parameters were calculated with the use of monoexponential (total apparent diffusion coefficient [ADCT]) and biexponential (pure diffusion coefficient [D], perfusion fraction [Fp]) model and compared among and within study groups using Kruskal–Wallis, Mann–Whitney, and Wilcoxon matched pairs tests. Diffusion parameters were correlated with eGFR using Spearman’s rank correlation coefficients. Results of tests with P values < 0.05 were considered statistically significant. Results Values of diffusion parameters, especially Fp, were lower in patients with a declined graft function; however, statistically significant intergroup differences were observed only in a limited number of parameters at the time of follow-up magnetic resonance imaging (MRI). None of the diffusion parameters from the baseline MRI correlated with the change in eGFR over time. Flow-related diffusion parameters calculated with the IVIM model showed high variability. Conclusion We observed a trend toward a decrease in values of diffusion parameters in patients with a declined graft function. Further research is needed to verify a clinical usefulness of this observation.

Influence of immunosuppressive regimen on diffusivity and oxygenation of kidney transplants – analysis of functional MRI data from the randomized ZEUS trial

“…First, ADCD as a marker of perfusion-free diffusion decreased in patients maintained on CsA whereas it increased in patients converted to everolimus. The ADCD has previously been shown to be reduced in various states of acute and chronic kidney diseases and to correlate to biological kidney function markers and interstitial fibrosis [9,18,[22][23][24][25]. This course parallels the improvement of eGFR in EVE-treated patients reported in the ZEUS trial, which was by trend also observed in our sub-study population.…”

“…The DWI-derived fraction of perfusion FP showed no significant changes over time nor between medication groups. Studies in kidney grafts have suggested lower FP values in cases of decreased graft function and acute rejection as well as to correlate to chronic tubulo-interstitial damage [18,24,27]. In our study, the number of cases might have prevented a significant finding.…”

Diffusion Weighted Magnetic Resonance Imaging in the Assessment of Renal Function and Parenchymal Changes in Chronic Kidney Disease: A Preliminary Study

“…Renal cysts and areas of parenchymal scarring were excluded form ROIs. The values of signal intensities from ROIs were averaged and incorporated into the locally developed script written in Matlab (R2014b, Mathworks, Natick, USA) and fitted in 2 ways [20]: 1) ADC was calculated using a standard mono-exponential model expressed by equation:…”

Noninvasive assessment of renal fibrosis by magnetic resonance imaging and ultrasound techniques

“…27 Findings-Similar to ADC, IVIM imaging detected decreased diffusion as well as lower perfusion in native kidney diseases [48][49][50][51][52][53][54][55] and dysfunctional renal allografts. [56][57][58] However, by yielding a larger number of renal physiological parameters, IVIM imaging offers new insights into renal pathophysiology. Studies demonstrated IVIM-measured diffusion coefficients had higher accuracy compared with ADC in discriminating renal lesions and that f p could provide information regarding lesion vascularity, 59,60 although others suggested that IVIM could not provide more information in the evaluation of renal dysfunction.…”