[en] Objective: To evaluate the feasibility of a novel arterial spin-labeling technique to characterize regions of hyper- and hypovascularity in experimental tumors in rabbits. Methods: VX2 tumors were implanted bilaterally in the thigh musculature of 17 New Zealand white rabbits. MR imaging sequences included a T2-weighted sequence and the arterial spin-labeling technique, flow-sensitive alternating inversion recovery with an extraradiofrequency pulse (FAIRER). Areas of viable and non-viable tumor were estimated based on the spin echo imaging sequences. Perfusion images were obtained from a magnitude subtraction of the labeled from the unlabeled images from the FAIRER sequence. Region of interest (ROI) analysis was performed in muscle, viable tumor regions, and necrotic tumor regions. Mean ROI signal intensities for viable tumor vs. muscle and necrotic tumor vs. muscle were compared using the student t-test. Results: Spin echo imaging demonstrated tumors in 30 of 34 thighs. Perfusion images were successfully obtained in all cases. The mean of signal intensity in muscle was 5.0 ± 0.8. The means of signal intensity in tumor were 11.7 ± 3.9 (left side) and 11.0 ± 3.1 (right side). The difference between muscle and tumor was statistically significant (P<0.001 for both sides). In all cases the calculated ratios of tumor vs. muscle were larger than 1, ranging from 1.2 to 5.1, indicating higher perfusion in tumor. There was no significant difference between left-sided tumors and right-sided tumors (P=0.59). Mean ROI were significantly less in regions of necrotic tumor compared to those in muscle (P<0.001). Conclusion: The FAIRER technique offers a simple method for non-invasive characterization of blood flow to vascular tumors. This technique may be valuable in diagnosing hypervascular areas of tumors that would be amenable to preoperative embolization. (authors)