Early assessment of acute renal rejection post-transplantation: a combined imaging and clinical biomarkers protocol

Abstract

Non-invasive evaluation of renal transplant function is crucial. Hence, a computer-assisted diagnostic (CAD) system is introduced in this paper to evaluate kidney function post-transplantation. The developed CAD system integrates clinical-based with diffusion weighted (DW) MR image-based biomarkers. The latter are derived from 3D DW-MRIs at multiple strengths and duration of the magnetic field (i.e. b-values). These DW-MRI scans were acquired at multiple geographical areas (Egypt and USA) using different scanner types (GE and Philips). The developed CAD system first segments kidneys using level-sets method and then estimates the DW-MRI image-markers, known as apparent diffusion coefficients (ADCs), from the segmented kidney. Then, the clinical biomarkers (serum creatinine and creatinine clearance) are integrated with the DW-MR image-markers (ADCs) resulted in new integrated markers known as integrated ADCs (IADCs). These IADCs are then used to construct cumulative distribution functions (CDFs) at multiple b-values. Finally, these markers (i.e. CDFs of the IADCs) are used to assess renal transplant status using different classifiers. Our CAD system demonstrates an almost consistent accuracy of 93%, sensitivity of 93%, and specificity of 92% in distinguishing acute rejection (AR) from non-rejection (NR) renal transplants, making the proposed diagnostic platform independent from the geographical area, scanner type, and classifier. These promising preliminary results are of high diagnostic accuracy and suggest that the developed CAD system might be noninvasively able to diagnose renal allograft status.