Spectral Computer Tomography Parameters Could Be Surrogate Imaging Markers To Detect Early Perfusion Changes In Diabetic Kidneys

Objective(s):Kidney microvasculopathy and renal hemodynamics changes have been demonstrated to be the baseline pathophysiological feature of DKD patients.The aim of this study was to validate the feasibility of spectral computer tomography(CT)parameters to identify early changes of renal perfusion in diabetic patients.Method(s):From August 2020 to June 2022,34 patients(age,57.7±10.7;male,20)clinically diagnosed with type 2 diabetes mellitus(DM)and 19 DM free control subjects(age,48.1±16.9;male,12)were selected from the in-patients in our hospital.All DM patients had normal albuminuria and estimated glomerular filtration rate(e GFR).Spectral parameters,including effective atomic number(Zeff),iodine density(ID),normalized iodine density(NID)and the slope of the energy spectrum curves(λ),between DM patients and control subjects were analyzed using independent-samples T test.Receiver operator characteristic curves(ROCs)were used to analysis the diagnostic performance of spectral parameters for distinguishing DM patients from control subjects.Result(s):The results shown that Zeff、ID,NID and λ 40-70 of renal cortex in diabetic patients group were significant higher than those in control subjects group(p<0.05),both in cortical and medullary phase.In the cortex phase,the diagnostic efficacy of cortical spectral CT parameters discriminating diabetic patients from control subjects were as follows: the AUC of ID value is0.816 at the optimal cutoff value 4.14,the AUC of Zeff value is 0.800 at the optimal cutoff value 9.26,the AUC of λ40-70 value is 0.822 at the optimal cutoff value 8.26,the AUC of NID value is 0.851 at the optimal cutoff value0.37.In medullary phase,the diagnostic efficacy of cortical spectral CT parameters discriminating diabetic patients from control subjects were as follows: The AUC of ID value is 0.769 at the optimal cutoff value 5.08,the AUC of Zeff value is 0.763 at the optimal cutoff value 9.58,the AUC of λ40-70 value is 0.766 at the optimal cutoff value 10.07,the AUC of NID value is0.79 at the optimal cutoff value 1.37.Delong test shown that there were no significant differences between the area under the ROC curve(AUC)of Zeff,λ40-70,ID and NID of renal cortex.Conclusion(s): Diabetic patients had suffer from abnormal kidney cortex perfusion at early stage.spectral CT could be an alternative protocol to identify early kidney injury in diabetic patients.