Ces radiol. 2009, 63(4):303-309

Assessment of the transplanted kidney using diffusion tensor imagingOriginal article

Jiří Ferda¹, Hynek Mirka¹, Tomáš Reischig², Ondřej Hes³, Boris Kreuzberg¹

¹ Department of Imaging Methods Charles University Hospital Plzen and Medical Faculty Plzen

² 1^st Department of Internal Medicine - Nephrology Charles University Hospital Plzen and Medical Faculty Plzen

³ Šikl's institute of Pathological Anatomy Charles University Hospital Plzen and Medical Faculty Plzen

Aim: To compare the diffusion parameters of the renal medulla and cortex and to evaluate the possibilities of the diffusion tensor imaging (DTI) in the assessment of the transplanted kidney allograft (TXK).

Method: 19 patients (13 males, 6 females, mean age 42.2 y) underwent DTI of TXK 12 hours before the biopsy after written consent; the study was approved by the local ethics committee. The imaging protocol contained a half-Fourier single shot T2 weighted sequence (HASTE) to plan 12-directional diffusion weighted sequence with b = 500 sec/mm² and b = 0 sec/mm². A DTI software package (produced by General Hospital Corporation, Boston, MA, USA) was used for calculation of apparent diffusion coefficient (ADC) and fraction anisotropy (FA) separately in the medulla and cortex. ADC and FA of the medulla and cortex within the same kidney were compared using a paired t-test. Two subgroups according to the biopsy finding, normal (n = 9) and pathologic (n = 10), were tested using the Wilcoxon-White test to find differences in ADC, FA, ADC medulla/cortex ratio and FA medulla/cortex ratio.

Results: A significant difference (p < 0.001) was found in FA between the medulla and cortex, but no difference between ADC values. FA values of the medulla aided to identify TXK affected by tubulointerstitial rejection (p = 0.05). Significant differences of the FA medulla/cortex ratio of (p < 0.001) and FA of the medulla (p = 0.05) were found between tested subgroups. Other differences were statistically insignificant.

Conclusion: The medulla differs from the cortex in FA values. The FA medulla/cortex ratio is a promising parameter in the assessment of the normal or pathological allograft.

Keywords: kidney transplantation, magnetic resonance imaging, diffusion tensor imaging, rejection

Grants and funding:

The study was supported by the research project MSM-0021620819 of the Czech Government.

Accepted: May 15, 2009; Published: December 1, 2009  Show citation