@article {Guo1636, author = {Wan-Yuo Guo and Yu-Te Wu and Hsiu-Mei Wu and Wen-Yuh Chung and Yi-Hsuan Kao and Tzu-Chen Yeh and Cheng-Ying Shiau and D. Hung-Chi Pan and Yue-Cune Chang and Jen-Chuen Hsieh}, title = {Toward Normal Perfusion after Radiosurgery: Perfusion MR Imaging with Independent Component Analysis of Brain Arteriovenous Malformations}, volume = {25}, number = {10}, pages = {1636--1644}, year = {2004}, publisher = {American Journal of Neuroradiology}, abstract = {BACKGROUND AND PURPOSE: Brain perfusion is disturbed by cerebral arteriovenous malformations (AVMs). Our study was conducted to determine the radiosurgical effects on this disturbed perfusion.METHODS: MR perfusion imaging with independent component analysis was performed in five healthy subjects and 19 patients with AVM before and after radiosurgery (every 6 months up to 2 years). Perfusion map relative cerebral blood volume (rCBV), cerebral blood flow (rCBF), and mean transient time (rMTT) were assessed. Regions of interest (ROIs) on AVM target sections were defined as follows: N, AVM nidus; H, the rest of the ipsilateral hemisphere; P, immediately posterior to the nidus; A, immediately anterior to the nidus; Ar, anterior remote; Pr, posterior remote. Similar ROIs in the contralateral hemisphere (N1, H1, P1, A1, Pr1, and Ar1) served as internal references. Perfusion ratios of ROI{\textendash}ROI1 were defined. Nonparameteric Mann-Whitney U tests and generalized linear models were used for statistical analysis.RESULTS: Before radiosurgery, patients{\textquoteright} H/H1 rCBV and rCBF ratios were significantly higher than those of healthy subjects (P \< .005), indicating AVM steal. Three types of perilesional perfusion disturbance were observed. From the first postradiosurgical follow-up at 6 months, N/N1 rCBV and rCBF ratios gradually decreased to 1.0 (both P \< .001), whereas rMTT ratios gradually increased to 1.0 (P \< .015); H/H1, A/A1, and P/P1 rCBV and rCBF ratios decreased after radiosurgery (P \< .005), indicating reversal of steal toward normal perfusion.CONCLUSION: Initial high transnidal flow and perinidal perfusion disturbances were demonstrated. They gradually changed toward normal perfusion after radiosurgery. This explains, in part, the pathophysiologic factors of AVM and therapeutic effects.}, issn = {0195-6108}, URL = {https://www.ajnr.org/content/25/10/1636}, eprint = {https://www.ajnr.org/content/25/10/1636.full.pdf}, journal = {American Journal of Neuroradiology} }