MR assessment of radiation-induced blood-brain barrier permeability changes in rat glioma model.
OBJECTIVE
To assess the potential of a T1-weighted, gadolinium-enhanced MR technique for quantifying radiation-induced changes of blood-brain barrier permeability in a model of stereotactically implanted intracerebral gliomas in rats.


METHODS
We calculated the gadolinium blood-to-tissue transport coefficient for gadopentetate dimeglumine from signal intensities in sequential MR images in nine control animals that were not irradiated and in five and three animals that had received 2500 cGy and 1500 cGy whole-brain irradiation, respectively, at 2 days before imaging.


RESULTS
The average blood-to-tissue transport coefficient values were 9.76 mL.kg-1.min-1 in the control group, 23.41 mL.kg-1.min-1 in the 2500 cGy group, and 25.63 mL.kg-1.min-1 in the 1500-cGy group. Blood-to-tissue transport coefficients were significantly higher after irradiation, indicating increased radiation-induced blood-brain barrier permeability. Similar increased blood-brain barrier leakiness in brain tumors after high-dose irradiation has been shown by previous nuclear medicine studies using quantitative autoradiography.


CONCLUSIONS
Contrast-enhanced dynamic MR of brain gliomas is a sensitive method to document radiation-induced blood-brain barrier breakdown. Quantitative gadolinium-enhanced MR may become a useful tool for the management of patients with brain tumors undergoing radiation therapy.
Krueck
W G
WG
Department of Radiology, University of Washington School of Medicine, Seattle 98195.
Schmiedl
U P
UP
Maravilla
K R
KR
Spence
A M
AM
Starr
F L
FL
Kenney
J
J
D000818:Animals; D001254:Astrocytoma / Q000378:metabolism* / Q000532:radiotherapy*; D001812:Blood-Brain Barrier / Q000528:radiation effects*; D001921:Brain / Q000378:metabolism / Q000528:radiation effects; D001932:Brain Neoplasms / Q000378:metabolism* / Q000532:radiotherapy*; D002199:Capillary Permeability / Q000528:radiation effects; D003287:Contrast Media / Q000008:administration & dosage / Q000493:pharmacokinetics; D004338:Drug Combinations; D005682:Gadolinium / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics; D019786:Gadolinium DTPA; D007089:Image Enhancement; D007262:Infusions, Intravenous; D008279:Magnetic Resonance Imaging; D008297:Male; D008536:Meglumine / Q000008:administration & dosage / Q000493:pharmacokinetics; D009942:Organometallic Compounds / Q000008:administration & dosage / Q000493:pharmacokinetics; D004369:Pentetic Acid / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000493:pharmacokinetics; D010539:Permeability / Q000528:radiation effects; D011879:Radiotherapy Dosage; D011882:Radiotherapy, High-Energy; D051381:Rats; D011916:Rats, Inbred F344; D014018:Tissue Distribution; D014407:Tumor Cells, Cultured
D003287:Contrast Media; D004338:Drug Combinations; D009942:Organometallic Compounds; D008536:Meglumine; D004369:Pentetic Acid; D005682:Gadolinium; D019786:Gadolinium DTPA