Role of Mri Corticomedullary Differentiation in the Assessment of Renal Post Transplantation Complications

Abstract

Objective: To evaluate MR features of renal corticomedullary differentiation in the assessment of renal allograft complications. Patients and Methods: Ten individuals with normal renal functions as a control group and thirty patients with post transplantation complications underwent MR examination. The signal intensity of the cortex and medulla were measured on coronal plane and the corticomedullary contrast (CMC) was calculated according to the equation: Results: All the patients with acute rejection showed loss of the corticomedullary differentiation CMD with a negative corticomedullary contrast CMC%, with sensitivity 75%, specificity 31%, positive predictive value 11% and negative predictive value 92%. One of the 2 cases with acute tubular necrosis (ATN) showed a decreased CMD with a CMC% of 6% and the other one showed a negative CMC% of-3%, having sensitivity 100%, specificity 36%, positive predictive value 15% and negative predictive value 100%. The cases with cyclosporine toxicity (Cs T)showed a wide variability in their CMD, where 40% showed normal CMC% of >9%, 17% showed a decreased CMD ranging between 0-9% and 43% showed loss of CMD. The MR assessment by this modality showed sensitivity 63%, specificity 28%, positive predictive value 18% and negative predictive value 75% detecting this type of medical complication. On the other hand, all patients with chronic graft rejection (CGN) showed decreased CMD ranging from 0-9%, with sensitivity 100%, specificity 32%, positive predictive value 7% and negative predictive value of 100%.There was a statistically significant decrease in the CMD seen in patients with chronic allograft rejection and those of the controls (p=0.02). Conclusion: Alteration in MRI corticomedullary differentiation can be pointer for impairment of renal function in renal allograft assessment, it is a sensitive but nonspecific indicator of renal disease.

Intravoxel Incoherent Motion-Diffusion-Weighted MRI for Investigation of Delayed Graft Function Immediately after Kidney Transplantation

“…These findings are consistent with the possibility that the transplanted kidneys incurred cellular edema and damage by IRI. Though there were significant differences in loss of CMD on T1WI between EGD and DGF, the image features neither reliably separated DGF from EGF nor DGFwC from DGFwoC, as others also have reported [ 29 , 30 ].…”

“…al. [ 29 ], reporting the wedge-shape areas of restricted diffusion and hypoperfusion in normal transplanted grafts and heterogeneous patterns resembling the tiger skin in ATN grafts. This could suggest that when testing overall renal function, effects of assessing tissue injury may be masked if ample healthy nephrons are present.…”