Assessment of Renal Pathological Changes in Lupus Nephritis Using Diffusion Weighted Imaging: A Multiple Correspondence Analysis

Abstract

Background/Aims: Renal pathological changes affect the motion of water molecules, which can be detected using diffusion-weighted imaging (DWI). The current study was performed to explore the correlation between renal tissue pathological injuries and DWI iconographical parameters in lupus nephritis (LN). Methods: Twenty adult patients with LN and 11 healthy volunteers were recruited. Patients with LN received renal biopsies and renal DWI-MRI inspections. The renal biopsy tissues were characterized based on the ISN/RPS 2003 classification. The volunteers, who were of comparable gender and age, only underwent renal DWI-MRI inspection. Four DWI parameters, namely, apparent diffusion coefficient (ADC), pure diffusion coefficient (D_t), pseudo-diffusion coefficient (D_p), and perfusion fraction (f_p), were calculated using monoexponential and biexponential functions, respectively. Data from different renal areas and pathological pattern groups were compared. Multiple correspondence analysis (MCA) was performed to explore the correlation between each DWI index and multiple pathological features. Results: ADC, D_t, and f_p values were lower in the LN group compared to the controls (P < 0.001) regardless of the renal area in the cortex and medulla. D_p values were higher in the LN group (P = 0.004). A difference in mean DWI parameters was found between three LN subgroups and the healthy volunteers, with the exception of the D_p index in the renal cortex. MCA showed that serious proliferative pathological injuries and lower ADC and D_t values were located in the same quadrant. The MCA plots of D_p and f_p provided similar results. Higher D_p and f_p values were located in the MCA plot quadrant with more serious proliferative pathological changes. Conclusion: DWI is a noninvasive technique that may be used to detect renal pathophysiological changes. Renal cell proliferation and intestinal fibrosis may impact the movement of water in certain microenvironments. Enhanced perfusion may be a compensatory mechanism that is associated with renal pathological injuries.