1naresh

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
                )

        )

)
1nareshArray
(
    [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
                )

        )

)


Artifacts and problems limiting artery evaluation
Type of Artifacts Description No. of Cases (incidence) on 64-Section CTA No. of Cases (incidence) on 16-Section CTA P Value (Fisher exact test)
Patient motion artifacts Gross motion during scan acquisition 0 (0%) 3 (2.7%) .247
Streak artifacts of venous origin Dense undiluted contrast in SCV, BCV; SVC obscures great vessel origins 32 (32%) 29 (25.7%) .363
Shoulder streak artifacts Photon starvation between shoulders obscures CCA, VA, IJV in lower neck 28 (28%) 33 (29.2%) .880
Metallic streak artifacts Dental hardware, cardiac defibrillator leads, spinal fusion hardware obscure adjacent arteries 26 (26%) 32 (28.3%) .759
Contrast material reflux Contrast reflux into veins of neck obscures adjacent VA 16 (16%) 17 (15%) .852
Flow artifacts: Altered flow dynamics (eg, slow flow) and rapid scanning time create appearance of dissection flap or nonopacification of patent vessel 14^a (14%) 0 (0%) <.001
    Arterial 
        Pseudo-dissection 5 
        Pseudo-occlusion 6 
        Differential attenuation 1 
    Venous 
        Pseudo-thrombosis 3 

Note:—CCA indicates common carotid artery; BCV, brachiocephalic vein; IJV, internal jugular vein; SCV, subclavian vein; SVC, superior vena cava; VA, vertebral artery; CTA, CT angiography. 


^a One patient had both pseudodissection and pseudo-occlusion.