Stratified CT analysis of renal, perirenal and renal sinus fat in type 2 diabetes mellitus and diabetic kidney disease.

BACKGROUND AND AIMS: To characterize stratified CT attenuation changes of renal parenchyma, perirenal fat, and renal sinus fat (RSF) in type 2 diabetes mellitus (T2DM) and diabetic kidney disease (DKD) using non-contrast CT, and to explore their correlation with disease progression.

METHODS AND

RESULTS

This retrospective study included 151 healthy controls and 579 T2DM patients (281 non-DKD, 298 DKD). Standardized ROI-based CT quantified renal parenchyma, perirenal fat, and RSF. Compared to controls, T2DM patients showed lower inner (IZRP) and outer zone of renal parenchyma (OZRP), and innermost zones of perirenal fat (IZPF), but higher middle (MZPF) and outermost zones of perirenal fat (OZPF) (all P < 0.05). RSF attenuation declined while RSF area enlarged progressively (P < 0.01). Lower OZRP and RSF attenuation correlated with reduced eGFR (ρ = -0.22), whereas larger RSF area and higher MZPF correlated with higher Scr and BMI (ρ = 0.25-0.52). Multivariate models identified increased RSF area (OR = 2.37), lower RSF attenuation (OR = 0.55) and reduced IZRP as independent predictors of T2DM; DKD progression independently associated with longer duration (OR = 1.05), hypertension (OR = 1.51), family history, higher MZPF/IZPF (OR = 1.53/1.00) and larger RSF area (OR = 1.29). Subgroup analysis: layer-specific differences concentrated in BMI <28 kg/m2, peaked at 10-20 years disease duration, and were largely independent of hypertension except for RSF area.

CONCLUSION

Stratified CT reveals complementary renal, perirenal, and RSF remodeling in T2DM and DKD. RSF expansion and perirenal fat attenuation provide independent imaging biomarkers for DKD risk stratification.