The feasibility of susceptibility weighted imaging for assessing renal difference of healthy volunteers after water loading / 中华放射学杂志

ABSTRACT

Objective To probe the feasibility of susceptibility weighted imaging (SWI) for evaluation of renal blood oxygenation level of healthy volunteers after water loading.Methods SWI of 11 healthy volunteers,acquired before (group 1) and after water loading (group 2),were assessed retrospectively by two radiologists with more than 10 years abdominal work experience independently.In those images of the same section plane derived from two groups,the phase values in cortex ((φ)cor) and medulla ((φ)med),difference between the same vein and surrounding tissue on phase map (△(φ)) were measured using SPIN software package,and the oxygen extraction fraction changes (△OEF) was calculated.The (φ)cor,(φ)med and △(φ) between two groups were compared by paired t test.And the intraclass correlation coefficient (ICC)was used to evaluate the consistency between two radiologists.Results For the radiologist 1,the (φ)cor,(φ)med and △(φ) were (0.046 ±0.019),(-0.014 ±0.003) and (1.3 ±0.4) rad in group 1,and were (0.047 ±0.014),(-0.012 ±0.005) and (1.1 ±0.4) rad in group 2 respectively,and no significant change was found in (φ)cor and (φ)med after water loading (t =-0.589 and-0.206,P ＞ 0.05 in all),except of in △(φ) (t =2.400,P ＜ 0.01).For the radiologist 2,the (φ)cor,(φ)med and △△(φ) were (0.049 ± 0.011),(-0.012 ± 0.004)and (1.5 ±0.4) rad in Group 1,and were (0.046 ±0.017),(-0.011 ±0.003) and (1.3 ±0.2) rad in group 2 respectively,there was no significant change in (φ)cor and (φ)med after water loading (t =0.590 and -0.974,P ＞ 0.05 in all),except of in △(φ) (t =2.760,P ＜ 0.05).Between two radiologists,the ICC of (φ)cor,(φ)med and △(φ) were 0.623,0.472 and 0.328 in group 1 and 0.599,0.442 and 0.445 in group 2 respectively.△OEF decreased about (-4.2 ± 2.3) c％ and (-4.3 ± 2.8) c％ measured by two radiologists respectively,and the consistency is good between two radiologists (ICC =0.784).Conclusion SWI provides a novel method to assess indirectly the oxygenation level of kidney,△OEF is an indicator with suitable reliability.