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  - Schmiedl, U P
AU  - Kenney, J
AU  - Maravilla, K R
TI  - Dyke Award Paper. Kinetics of pathologic blood-brain-barrier permeability in an astrocytic glioma using contrast-enhanced MR.
DP  - 1992 Jan 01
TA  - American Journal of Neuroradiology
PG  - 5--14
VI  - 13
IP  - 1
4099  - http://www.ajnr.org/content/13/1/5.short
4100  - http://www.ajnr.org/content/13/1/5.full
SO  - Am. J. Neuroradiol.1992 Jan 01; 13
AB  - PURPOSE The feasibility of measuring blood-brain barrier permeability was studied in a 36B-10 brain glioma model in rats.MATERIALS AND METHODS In stage I of our study, sequential MR images of glioma-implanted rats were obtained following intravenous administration of three contrast agents of different molecular sizes--Gd-DTPA, polylysine-(Gd-DTPA), and albumin-(Gd-DTPA). In a second set of experiments, sequential MR imaging with Gd-DTPA, quantitative measurements of plasma Gd-DTPA concentration, and postmortem tumor Gd-DTPA measurements were used to estimate the blood-to-tissue transport coefficient (Ki) in the rat glioma model at 11 and 15 days postimplantation.RESULTS In stage I, Gd-DTPA caused rapid and greatest tumor enhancement with a significant washout from the tumor during the 120-min experiment. Tumor enhancement using polylysine-(Gd-DTPA) occurred later and was significantly less compared to Gd-DTPA. Tumor signal intensity increased only slowly over time and the peak level of enhancement was least using albumin-(Gd-DTPA). In stage II, the mean (+/- 1 SD) Ki values were 1.1 +/- .24 at 11 days, and 9.3 +/- .8 at 15 days postimplantation. These results correspond well with published data obtained by autoradiography.CONCLUSION We believe that the differential enhancement pattern using contrast agents of different molecular sizes reflects a differential permeability of the pathologic blood-brain barrier, and that our studies demonstrate the feasibility of using frequent sequential images and a graphical approach to Ki calculation to determine the blood-to-tissue transport coefficient using contrast-enhanced MR.