Cellular versus vascular rejection in transplant kidneys. Correlation of radionuclide and Doppler studies with histology

The presence of two distinct subtypes of renal allograft rejection are well documented by histological studies. The differentiation between vascular rejection (VR) and cellular rejection (CR) is essential for proper management by avoiding the need for unnecessary and potentially harmful immunosuppressive treatment of VR. A histological pattern with features that are similar and confusable with some cases of rejection may be seen in cyclosporin A toxicity (CyT). To evaluate the efficiency of Guyʼs perfusion index (GPI) and the Doppler pulsatility index (DPI) in differentiating these two histological subtypes, a prospective study was designed in which a total of 140 radionuclide tests and 133 ultrasounds scans performed on the same day on 58 patients during the first 3 months post-transplant were analysed, and the results correlated with the histological findings of 84 renal biopsies. Results show that the GPI had a sensitivity of 86.5% and a specificity of 94% in differentiating VR and CyT from CR, while the DPI had values of 83% and 69%, respectively. Chi-squared analysis showed a higher significant association between the GPI and histology (P < 0.0001) compared to that of the DPI and histology (P < 0.005), while Youdenʼs index (J) showed a significant difference (P < 0.05) between GPI and DPI. It is concluded that GPI is more sensitive and specific than DPI in differentiating transplants that are well perfused from those with poor perfusion (VR and CyT).