Functional evaluation of normothermic ischemia and reperfusion injury in dog kidney by combining MR diffusion-weighted imaging and Gd-DTPA enhanced first-pass perfusion.
OBJECTIVE
To evaluate functional alterations of renal ischemia and reperfusion injury using MR diffusion-weighted imaging and dynamic perfusion imaging.


METHODS
Twelve dogs were randomly divided into four groups. Animal renal ischemia was respectively induced for 30 (group 1), 60 (group 2), 90 (group 3), and 120 (group 4) minutes by left renal artery ligation under anesthesia. Using a 1.5 T MR system, true-FISP, TSE, EPI, and DWI sequences were acquired in five different periods; specifically, pre-ischemia, onset-ischemia, late ischemia, onset-reperfusion, and post-reperfusion. Moreover, a turbo-FLASH sequence (TR/TE/TI/FA = 5.8/3.2/400 msec/10 degrees ) with a temporal resolution of 1.16 seconds was acquired. Signal intensity (SI) was measured in the cortex, outer medulla, and inner medulla of kidney. Apparent diffusion coefficient (ADC) values were calculated, and SI was plotted as a function of time.


RESULTS
In all animals, significant SI changes of the left kidney on T2/T2*WI were detected following ischemia-reperfusion insult compared to corresponding values of the right kidney. Following ligation, the ADC values decreased in all layers of the left kidney. Immediately after the release of ligation, ADC values in both outer and inner medulla of the left kidney remained lower than those of the right kidney in those animals which were induced with renal ischemia for 60, 90, and 120 minutes. In all groups, a uniphasic enhancement pattern was observed in the outer and inner medulla of the left kidney, accompanied by a decrease of the area under the curve.


CONCLUSIONS
Our results suggest that MR diffusion-weighted imaging and dynamic perfusion imaging are useful in identifying renal dysfunction following normothermic ischemia and reperfusion injury.
Liu
Ai-Shi
AS
Department of Radiology, Peking University Third Hospital, Beijing, Peoples Republic of China. liuaishi2000@yahoo.com
Xie
Jing-Xia
JX
D000818:Animals; D019540:Area Under Curve; D001831:Body Temperature / Q000502:physiology; D003287:Contrast Media / Q000008:administration & dosage; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D004285:Dogs; D005240:Feasibility Studies; D019786:Gadolinium DTPA / Q000008:administration & dosage; D007668:Kidney / Q000473:pathology*; D008026:Ligation; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011507:Proteinuria / Q000652:urine; D015427:Reperfusion Injury / Q000175:diagnosis* / Q000473:pathology
D003287:Contrast Media; D019786:Gadolinium DTPA