Kidney Week

Abstract: FR-PO294

Kidney Functional MRI: A Potential Noninvasive Assessment of Early Change and NCC Function in Chinese Gitelman Syndrome Patients

Session Information

• Fluid and Electrolytes: Clinical
  October 26, 2018 | Location: Exhibit Hall, San Diego Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Fluid and Electrolytes

• 902 Fluid and Electrolytes: Clinical

Authors

• Peng, Xiaoyan, Peking Union Medical College Hospital, Beijing, China

Xiaoyan Peng,

• Zhang, Gu-Mu-Yang, Peking Union Medical College Hospital, Beijing, China

Gu-Mu-Yang Zhang,

• Tian, Dongli, Peking Union Medical College Hospital, Beijing, China

Dongli Tian,

• Sun, Hao, Peking Union Medical College Hospital, Beijing, China

Hao Sun,

• Chen, Limeng, Peking Union Medical College Hospital, Beijing, China

Limeng Chen,

Background

Gitelman syndrome (GS) is an inherited salt-losing tubulopathy with Na⁺-Cl^-cotransporter (NCC) dysfunction. Diffusion kurtosis imaging (DKI) and inteavoxel incoherent motion imaging(IVIM) MRI are functional MRI(fMRI) which could disclose more precise tissue structure and water diffusion. Recently, we observed fMRI associated well with the pathologic changes in IgA nephropathy. In this study we first applied the novel technique in the kidney of GS patients.

Methods

Twenty patients with genetically confirmed GS and 24 age and gener matched healthy volunteers were enrolled. DKI and IVIM were performed at a clinical 3T MR scanner. The DKI parameters (K=mean kurtosis, D=mean diffusivity, ADC=apparent diffusion coefficient) and IVIM parameter(f_P=microvascular perfusion fraction, D_P=pseudodiffusion, D=diffusion coefficients) were generated by a post-processing software.The association between parameters and clinical data were investigated. The in vivo NCC function of patients were evaluated by thiazide test using _△FECl(the increment of fractional excretion of Cl^-).

Results

The mean age of GS patients was 28.4±10.2y and 45.8% were male with a mean onset age of 22.2±11.7y. At admission, the mean serum K⁺and Mg²⁺ was 3.22±0.55 mmol/L and 0.68±0.16 mmol/L. GS patients showed decreased reaction to thiazide test. Compared to controls, lower DKI-ADC (1.45±0.19 vs 1.55±0.12,P=0.048), which indicating greater diffusion restriction, was observed in the renal medulla of GS. Lower IVIM-DP (117.8±46.0 vs. 151.3±56.3,P=0.039) indicating less microvascular perfusion, was observed in the renal cortex of GS.
Among GS patients, in DKI the cortex ADC was associated well with plasma upright renin activity and blood pressure. The D value and K value correlated well with serum Cl^-( D: r=-0.670, P=0.001; K: r=-0.470, P=0.037) and HCO₃^-(D: r=0.709, P＜0.001; K: r=0.469,P=0.037). In the kidney medulla, only K value associated well with serum Cl^-(r=-0.514,P=0.020). In IVIM, both the cortex D (r=0.702,P=0.035) and medulla D_P(r=-0.683, P=0.048) correlated well with _△FECl.

Conclusion

DKI and IVIM MRI potentially provides a novel method for examining microvascular perfusion and diffusion in the kidney of GS patients and can serve as a noninvasive assessment of early change and NCC function in Chinese Gitelman syndrome patients.