Assessment of renal interstitial fibrosis in glomerulonephritis using compartmental and non-compartmental diffusion...

This prospective study designed to evaluate the diagnostic capabilities of diffusion kurtosis imaging (DKI) and intravoxel incoherent motion (IVIM) in assessing renal interstitial fibrosis in glomerulonephritis (GN).

GN was induced in rats by tail vein injection of puromycin amino nucleoside. Animals were sacrificed at six time points (weeks 2, 4, 6, 10, 14, 16) to capture progressive fibrosis, which was graded T0, T1, and T2 by Masson's trichrome staining. A total of 43 rats included in the final analysis were compared across fibrosis stages, and diagnostic performance was assessed by receiver operating characteristic curve analysis.

With increasing fibrosis, MK and FA rose significantly, whereas MD, D, D*, and f declined. Fibrosis categories correlated positively with MK and FA and negatively with MD, D, D*, and f (all P < 0.05). When differentiating T0 from healthy control group and T1 from T0, medullary FA in DKI provided the highest area under the curve (AUC), while medullary D* in IVIM showed the highest AUC. The combination of medullary D* and FA yielded significantly better AUC than individual parameters (P < 0.05). In distinguishing T1 from T2, cortical MK in DKI provided the highest AUC, while medullary D* in IVIM was the most AUC. However, no statistically significant difference was found between the combined and individual parameters (P > 0.05).

Mild-to-moderate GN-related fibrosis (T0-T1) was more effectively differentiated using medullary IVIM parameters, whereas advanced fibrosis (T2) was better distinguished by cortical DKI metrics. The combined application of IVIM and DKI provided complementary value for fibrosis staging.