Use of intravoxel incoherent motion diffusion-weighted imaging to detect early changes in diabetic kidneys

The purpose of the study was to examine differences in kidney intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) parameters in early-stage diabetic patients versus healthy controls.

Nineteen type 2 diabetic patients (group A) with a urinary albumin-to-creatinine ratio (ACR) < 30 mg/g and an estimated glomerular filtration rate (eGFR) of 80-120 mL/(min 1.73 m²) and twelve healthy volunteers (group B) were recruited. Kidneys were scanned with 1.5-Tesla IVIM-DWI. Nine b values (0, 50, 100, 150, 200, 300, 400, 600, and 800 s/mm²) were used. The parameters derived from IVIM-DWI were calculated for each kidney by two radiologists and included the perfusion fraction (f), diffusion coefficient (D), and pseudo-diffusion coefficient (D*). The mean values of f, D, and D* were calculated by selecting multiple regions of interest in the kidney. The diagnostic performance of the f, D, and D* values for the diagnosis of early diabetic kidney changes was determined by receiver operating characteristic analysis. Three radiologists independently measured the parameters derived from IVIM-DWI in the two groups by free-hand placing regions of interest, and the interclass coefficients (ICCs) were analyzed by SPSS.16.0 software.

The f values of the kidneys were significantly higher in diabetic patients than in healthy volunteers. The D value of the kidneys was significantly lower in diabetic patients than in healthy volunteers. No significant differences in the D* values of the kidneys were observed between diabetic patients and healthy volunteers. The D values of the right kidneys were significantly higher than those of the left kidneys in both groups. The results of the receiver operating characteristic analysis were as follows: left kidney-f value AUC = 0.650 (cutoff point ≥ 27.49%) and D value AUC = 0.752 (cutoff point ≤ 1.68 × 10^-3 mm²/s); and right kidney-f value AUC = 0.650 (cutoff point ≥ 28.24%) and D value AUC = 0.752 (cutoff point ≤ 1.81 × 10^-3 mm²/s). The diagnostic performance of the D* value was very low (AUC < 0.6). No significant differences were present between the areas under the curves of the f and D values (P > 0.05). The ICCs of the f value and D value were between 0.637 and 0.827. The ICC of the D* value was less than 0.3.

The results of our study suggest that changes in kidneys detected by IVIM-DWI may serve as indicators of early diabetic kidney disease.