RESUMO
Objective To explore the characteristics and the clinical application of MR perfusion weighted imaging(PWI)in the normal kidneys and the renal diseases.Methods Thirty-one subjects including 9 cases without urinary diseases,14 cases with renal carcinoma,6 cases with renal cyst and 2 cases witll renal tuberculosis who had been examined with T1WI,T2WI and PWI were analyzed retrospectively.All the data were processed by a workstation to obtain time-signal intensity curves,color perfusion maps and relative perfusion value.The relative renal blood volume(RBV),relative renal blood flow(RBF),mean transition time(MTT)and the time to peak(TTP)in the normal renal cortex and medulla and the renal lesions were calculated.Comparisons between the right and the left normal kidneys,and between the cortex and the medulla of the normal kidneys were performed using t test,and comparisons between the normal and the abnormal kidneys were performed using q test.Results Relative RBV and relative RBF of the cortex were 1.33±0.08 and 1.44±0.09 respectively,and for medulla were 0.58±0.05 and 0.78±0.13 respectively(t=9.2241 and 5.0336,P＜0.01);MTT(1.11±0.08)and TTP (1.04±0.06)of the cortex has no difference with that of the medulla(0.97±0.04 and 0.94±0.03)in the normal kidneys(t=2.2551 and 2.2613.P＞0.05).The values of relative RBF of the renal carcinoma (1.35±0.34)were significantly higher than that of the normal tissues(1.02±0.06)(q=3.0882,P＜0.01).Conclusion PWI is able to demonstrate the hemodynamic change of the normal renal tissues and the renal lesions,and it maybe an ideal method for showing the functional changes of the kidney and for differentiating the renal diseases.
