Assessment of early renal allograft function after transplantation using renal intravoxel incoherent motion imaging and T1 mapping / 中华放射学杂志

ABSTRACT

Objectives To investigate the ability of T1 mapping and intravoxel incoherent motion imaging (IVIM) parameters for evaluating renal allografts at the early stage after renal transplantation. Methods This prospective study protocol was approved by the local ethics committee, and written informed consent was obtained from all subjects. Sixty two recipients 2 to 4 weeks after kidney transplantation and 20 healthy volunteers (control group) underwent routine MRI, T1 mapping, and IVIM imaging (11 b values, 0 to 700 s/mm2). Recipients were divided into two groups base on their estimated glomerular filtration rate (eGFR)37 recipients with good allograft function (eGFR≥60 ml·min-1·1.73 m-2) and 25 recipients with impaired allograft function (eGFR<60 ml·min-1·1.73 m-2). The ADC, true diffusion coefficient (ADCslow), pseudo-diffusion coefficient (ADCfast), perfusion fraction (f) and T1 values were measured on both cortex and medulla. Differences among groups were compared using the one-way analysis of variance. Correlations between eGFR and the parameters in renal allografts were assessed by using Pearson correlation analysis. ROC was performed to assess the diagnostic utilities of using these parameters to discriminate allografts with impaired function from good function. Results Excepting for cortical T1, ADCfast and medullary T1, f values, allografts with good function showed no differences in other parameters compared with healthy control. Excepting for medullary T1 and ADCfast,the other values showed significantly differences in allografts with impaired function compared to allografts with good function (all P<0.05). Excepting for medullary f and ADCfast values, allografts with impaired function showed significantly differences in the parameters compared with good function group(all P<0.05). In renal allografts, excepting for medullary T1, ADCfast, and f values, cortical T1 exhibited a negative correlation with renal function, and there was a significant positive correlation between eGFR and other parameters. Cortical T1 value showed high sensitivity(91.9%) to discriminate renal allografts with different function, with the threshold of 17.36 × 102 ms, and ADC value showed high specificity(96.0%)with the threshold of 1.98 × 10-3 mm2/s. Conclusion T1 mapping and IVIM technique may be useful for detecting renal allograft dysfunction, and be a reliable imaging for evaluating and monitoring allograft function.