Yang Wen1, Yun Peng1, Dan Dan Zheng2, Zhi Chen3, Guang Heng Yin1, Yan Qiu Lv1, Chen Xu1, and Yang Fan2
1Department of Radiology, Beijing Children’s Hospital Affiliated to Capital Medical University, Beijing, China, People's Republic of, 2GE Healthcare, MR Research China, Beijing, China, People's Republic of, 3Department of Nephrology, Beijing Children’s Hospital Affiliated to Capital Medical University, Beijing, China, People's Republic of
Synopsis
To evaluate the feasibility of DKI in assessment of renal functions
in children with chronic kidney disease (CKD).
Materials and Methods: This study was IRB approved and informed consent was obtained. Fifteen
pediatric patients with CKD and nine children without renal diseases underwent DKI
of kidneys. Maps of fractional anisotropy (FA), mean diffusivity (MD), mean
kurtosis (MK), radial kurtosis (K⊥) and axial kurtosis (K//) were produced.
Results: There is a significant difference of kurtosis
metrics and FA of renal medulla compared to those of renal cortex in both the
control group and CKD group. FA, MD, K⊥
and MK values of both the cortex and medulla of kidney
have significant differences between patients with CKD and control group.
Conclusion: DKI could be a useful tool in the evaluation of renal function in children
with CKD.Purpose
Diffusion-weighted imaging
(DWI) and diffusion tensor imaging (DTI) have demonstrated clinical potential
to evaluate renal functions in patients with chronic kidney disease (CKD)
[1, 2]. However, inconsistent assessments of renal functions
were obtained using DWI/DTI in patients with CKD
[1-3]. Based on non-Gaussian properties of water
diffusion, diffusional kurtosis imaging (DKI) can offer additional information
about microstructural complexity of biological tissues
[4]. Recently, due to respiratory triggering technique, the
feasibility of DKI in human kidneys has been confirmed
[4, 5]. The purpose of this study is to prospectively evaluate
the feasibility of DKI in assessment of renal functions in children with CKD.
Materials and Methods
This study was IRB approved and informed consent was obtained. Fifteen
pediatric patients with CKD (aged from 3 years to 10 years) and nine children without
renal diseases (age ranging from 3 to 7 years) as a control group were enrolled
in this study. All subjects underwent transverse, respiratory-triggered,
single-shot spin-echo echo-planar DKI of kidneys. DKI with 15 directions and 3 b-values
(0, 500, 1000 s/mm
2) was performed on a 3.0T MR scanner (GE DISCOVERY
MR 750, USA)
after scans of routine anatomical images. Maps of fractional anisotropy (FA),
mean diffusivity (MD), mean kurtosis (MK), radial kurtosis (K
⊥) and axial kurtosis (K
//)
were produced. For each subject, three representative axial slices in the upper
pole, mid-zone and lower pole were selected in the left and right kidneys. On
each selected slice, three regions of interest were drawn on the renal cortex
and another three on the medulla as shown in Fig.1A. Statistical comparisons were conducted using
t-test and analysis of variance.
Results
No statistically significant difference was observed between the
left and right kidneys for all metrics in both the control group and CKD group.
Kurtosis metrics (MK, K
//, K
⊥) obtained in the renal medulla were significantly higher than those
of cortex for both groups. FA of the medulla was significant higher than that
of the cortex in both the normal and affected kidneys (p < 0.001). MD (mm
2/ms)
was lower in the medulla than in the cortex only in control group (p < 0.01),
and there is no statistically significant difference in CKD group (p=0.475). Regardless
of whether eGFR (estimated glomerular filtration rate according to the serum creatinine
level) was reduced, FA of both the cortex and the medulla was significantly
lower in patients with CKD than in control group (p < 0.01), MD of both the
cortex and the medulla was significantly higher in patients with CKD than in
controls (p < 0.05), and K
⊥
and MK of both the cortex and the medulla were lower in
patients with CKD than in controls (p < 0.05). No statistically significant
differences of K
// were observed between two groups of subjects. A
direct correlation between DKI parameters and the eGFR was not found.
Discussion and Conclusion
This study demonstrates
that there is a significant difference of kurtosis
metrics and FA of renal medulla compared to those of renal cortex in both the control
group and CKD group. FA, MD, K
⊥ and MK values of both the cortex and medulla of kidney have significant
differences between patients with CKD and control group. The preliminary
results suggest that DKI could be a useful tool in the evaluation of renal
function in children with CKD.
Acknowledgements
No acknowledgement found.References
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