Diffusional kurtosis imaging in assessing renal function and pathology of IgA nephropathy: a preliminary clinical study.

AIM

To evaluate renal fibrosis in immunoglobulin A nephropathy (IgAN) using diffusion kurtosis imaging (DKI).

MATERIALS AND METHODS

Twenty patients with biopsy-proven IgAN were enrolled. DKI was performed on a clinical 3 T magnetic resonance imaging (MRI) system, and region-of-interest measurements were conducted to determine mean kurtosis (K), mean diffusivity (D), and apparent diffusion coefficient (ADC) of the kidney cortex. Renal biopsy specimens were scored based on the severity of renal fibrosis. The associations between the DKI data and clinicopathological parameters were investigated.

RESULTS

Both the K and ADC were not only well correlated with the estimated glomerular filtration rate, but also significantly associated with the pathological scores of fibrosis, including the glomerular sclerosis index (K: r=0.759, p<0.001; ADC: r=-0.636, p=0.003) and the percentage of tubular atrophy and interstitial fibrosis (K: r=0.767, p<0.001; ADC: r=-0.702, p=0.001). Further receiver operating characteristic analysis showed that K demonstrated better diagnostic performance in discriminating severe glomerulosclerosis (area under curve [AUC] 0.970, sensitivity 81.8%, specificity 100%), and ADC displayed better capabilities in identifying severe tubular atrophy/interstitial fibrosis (AUC 0.976, sensitivity 100%, specificity 92.9%).

CONCLUSION

This DKI method can be used to detect renal fibrosis in IgAN in a non-invasive manner and may provide additional information for characterisation and surveillance.