1naresh<pre>Array
(
    [urn:ac.highwire.org:guest:identity] => Array
        (
            [runtime-id] => urn:ac.highwire.org:guest:identity
            [type] => guest
            [service-id] => ajnr-ac.highwire.org
            [access-type] => Controlled
            [privilege] => Array
                (
                    [urn:ac.highwire.org:guest:privilege] => Array
                        (
                            [runtime-id] => urn:ac.highwire.org:guest:privilege
                            [type] => privilege-set
                            [privilege-set] => GUEST
                        )

                )

            [credentials] => Array
                (
                    [method] => guest
                )

        )

)
1naresh<pre>Array
(
    [urn:ac.highwire.org:guest:identity] => Array
        (
            [runtime-id] => urn:ac.highwire.org:guest:identity
            [type] => guest
            [service-id] => ajnr-ac.highwire.org
            [access-type] => FreeToRead
            [privilege] => Array
                (
                    [urn:ac.highwire.org:guest:privilege] => Array
                        (
                            [runtime-id] => urn:ac.highwire.org:guest:privilege
                            [type] => privilege-set
                            [privilege-set] => GUEST
                        )

                )

            [credentials] => Array
                (
                    [method] => guest
                )

        )

)
PT  - JOURNAL ARTICLE
AU  - Guo, Wan-Yuo
AU  - Wu, Yu-Te
AU  - Wu, Hsiu-Mei
AU  - Chung, Wen-Yuh
AU  - Kao, Yi-Hsuan
AU  - Yeh, Tzu-Chen
AU  - Shiau, Cheng-Ying
AU  - Pan, D. Hung-Chi
AU  - Chang, Yue-Cune
AU  - Hsieh, Jen-Chuen
TI  - Toward Normal Perfusion after Radiosurgery: Perfusion MR Imaging with Independent Component Analysis of Brain Arteriovenous Malformations
DP  - 2004 Nov 01
TA  - American Journal of Neuroradiology
PG  - 1636--1644
VI  - 25
IP  - 10
4099  - http://www.ajnr.org/content/25/10/1636.short
4100  - http://www.ajnr.org/content/25/10/1636.full
SO  - Am. J. Neuroradiol.2004 Nov 01; 25
AB  - 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–ROI1 were defined. Nonparameteric Mann-Whitney U tests and generalized linear models were used for statistical analysis.RESULTS: Before radiosurgery, patients’ H/H1 rCBV and rCBF ratios were significantly higher than those of healthy subjects (P &amp;lt; .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 &amp;lt; .001), whereas rMTT ratios gradually increased to 1.0 (P &amp;lt; .015); H/H1, A/A1, and P/P1 rCBV and rCBF ratios decreased after radiosurgery (P &amp;lt; .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.