Susceptibility-weighted imaging for the assessment of chronic renal injury / 中华放射学杂志

ABSTRACT

Objective To explore the value of susceptibility-weighted imaging (SWI) for the assessment of chronic renal injury. Methods Thirty-nine patients with clinical diagnosis of chronic renal injury (RI group) who underwent routine renal MRI and SWI examination were retrospectively analyzed. They were divided into mild injured group (15 cases) and moderate to severe injured group (24 cases) by estimated glomerular filtration rate (eGFR). At the same time, 17 volunteers without chronic renal injury who had normal serum creatinine (Scr) and blood urea nitrogen were recruited as control group. All subjects underwent routine renal MRI and SWI examination. The ratios of cortex to medulla were measured and calculated in both kidneys' magnitude image and susceptibility weighted image, which were indicated as C/MMAG and C/MSWI. Independent sample t test was used to compare the differences of C/MMAG and C/MSWI between control group and RI group, and paired sample t test was used to compare the differences betweenC/MMAG and C/MSWI in each group. One-way ANOVA was used to compare the difference of C/MMAG and C/MSWI between the control group and the different RI groups. ROC was employed to assess the diagnostic efficacy of C/MMAG and C/MSWI in renal injury. Pearson linear correlation analysis was used to evaluate the correlation between C/MMAG, C/MSWI and eGFR, Scr in patients with renal injury. Results The C/MMAG and C/MSWI in the RI group were 1.101±0.039 and 1.071±0.046, respectively. C/MSWI was obviously lower than C/MMAG, and the difference was statistically significant (t=5.056, P0.05). The C/MMAG and C/MSWI in the RI group were obviously lower than those in the control group, and the difference was statistically significant (t=4.564, 6.122;P0.05). The area under ROC of C/MMAG and C/MSWI in diagnosis of renal injury were 0.853 and 0.952, respectively. C/MMAG was positively correlated with eGFR (r=0.460,P<0.01). Conclusions Susceptibility-weighted imaging can be used to assess chronic renal injury. Although it cannot reflect the degree of renal function damage, it has some value in the early diagnosis of mild renal injury.