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  - Larson, T C
AU  - Kelly, W M
AU  - Ehman, R L
AU  - Wehrli, F W
TI  - Spatial misregistration of vascular flow during MR imaging of the CNS: cause and clinical significance.
DP  - 1990 Sep 01
TA  - American Journal of Neuroradiology
PG  - 1041--1048
VI  - 11
IP  - 5
4099  - http://www.ajnr.org/content/11/5/1041.short
4100  - http://www.ajnr.org/content/11/5/1041.full
SO  - Am. J. Neuroradiol.1990 Sep 01; 11
AB  - Spatial misregistration of signal recovered from flowing spins within vascular structures is a common phenomenon seen in MR imaging of the CNS. The condition is displayed as a bright line or dot offset from the true anatomic location of the lumen of the imaged vessel. Its origin is the time delay between application of the phase- and frequency-encoding gradients used to locate spins within the plane of section. The principal condition necessary for the production of spatial misregistration is flow oblique to the axis of the phase-encoding gradient. Flow-related enhancement (entry slice phenomenon), even-echo rephasing, and gradient-moment nulling contribute to the production of the bright signal of spatial misregistration. Familiarity with the typical appearance of flow-dependent spatial misregistration permits confirmation of a vessel&#039;s patency; identification of the direction of flow; estimation of the velocity of flow; and differentiation of this flow artifact from atheromas, dissection, intraluminal clot, and artifacts such as chemical shift.