Functional evaluation of normothermic ischemia and reperfusion injury in dog kidney by using MR perfusion-weighted imaging / 中华放射学杂志

ABSTRACT

Objective To evaluate the functional alternations of canine renal ischemia and reperfusion injury by using MR perfusion-weighted imaging, and to correlate the imaging with the pathologic findings. Methods Using 1. 5 T MR system, four groups of three anesthetized dogs each were studied by left renal artery ligation for 30-, 60-, 90-, and 120-min, respectively, after the removal of ligation, reperfusion injury was suffered for one hour. True-FISP, TSE, and EPI sequences were performed in five different time phases ( pre-ischemia, onset-ischemia, post-ischemia, onset-reperfusion, and post-reperfusion). Finally, IR-turbo-FLASH sequence (TR 5. 8 ms, TE 3. 2 ms, TI 400 ms, FA 12?) with a temporal resolution of 1. 16 s was performed. Signal intensity (SI) in cortex, outer medulla, and inner medulla was measured. SI was plotted as a function of time. Peak height (P) , time to peak (Tp) , and the area (A) under the time-course curves after the intravenous injection of Gd-DTPA were estimated. Blood and urine examples were collected for measuring serum creatinine level and urinary protein before and after the insult. Histologic examination was performed with light and electron microscopy in all dogs. Results After arterial ligation,there was marked and significant reduction in the SI of each layer of left kidney on true-FISP, TSE, and EPI, except for the SI of inner medulla on TSE. After the removal of ligation,there were no significant differences in the SI of cortex of both kidneys, however, significant differences in the SI of outer and inner medulla of both kidneys remained on EPI in all groups. The turbo-FLASH study clearly depicted the three-phase pattern of SI changes in each layer on right kidney. The uniphasic enhancement pattern in all groups was showed in outer and inner medulla on left kidney, with the area under the curve decreased. Conclusion This preliminary study shows that MR perfusion-weighted imaging may be useful and very promising for the evaluation of renal dysfunction following normothermic ischemia and reperfusion injury.