Quantitative contrast-enhanced ultrasound of renal perfusion: a technology for the assessment of early diabetic nephropathy in cynomolgus macaques with type 2 diabetes mellitus

The aim of this study was to investigate the effectiveness of contrast-enhanced ultrasound (CEUS) in predicting early nephropathy in cynomolgus macaques with spontaneous type 2 diabetes mellitus (T2DM). Six cynomolgus macaques with spontaneous T2DM and six normal cynomolgus macaques (Group 1) were included in this study. The time–intensity curve was used to obtain parameters such as peak values, red blood volume (RBV), red blood flow (RBF), time to peak (TTP), and mean transit time (MTT). Biopsy renal tissue samples were assessed histopathologically. Six cynomolgus macaques with spontaneous T2DM were subgrouped into T2DM without nephropathy group (Group 2) and T2DM with nephropathy group (Group 3) based on histopathological findings. Peak value had the largest area under the curve comparing with RBF, RBV, TTP, MTT. The sensitivity and specificity of peak value with cut-off value of 38.65 dB for the diagnosis of DN were 98.3% and 83%, respectively. Peak value, RBV, and RBF in Group 3 was significantly decreased compared with Group 1 and Group 2 (P = 0.000, x2 = 23.99; P = 0.003, x2 = 9.14; P = 0.02, x2 = 5.14). The perfusion parameter of peak value in CEUS might be useful in predicting early diabetic nephropathy in spontaneous T2DM cynomolgus macaques.