MRI of the cat brain in the study of vascular permeability after intraarterial carotid injection of triolein.
BACKGROUND
Triolein emulsion embolization into the carotid artery depicts reversible increased vascular permeability that can promote the effect of chemotherapy or can reduce the amount of chemotherapeutic drugs for equivalent effectiveness.


OBJECTIVE
To establish the minimum dosage of 0.5% triolein for studying vascular permeability changes in a triolein emulsion model.


METHODS
Sixty-six cats were divided into six groups based on the amount of emulsified triolein (0.5%) infused into the carotid artery: group 1 (n=12, 6 ml/kg), group 2 (n=12, 4.5 ml/kg), group 3 (n=12, 3 ml/kg), group 4 (n=10, 1.5 ml/kg), group 5 (n=10, 1 ml/kg), and group 6 (n=10, 3 ml/kg of saline (control group)). T1-weighted, T2-weighted, and post-contrast T1-weighted MRI was performed 2 h after the infusion of the triolein emulsion. Contrast enhancement ratios (CERs) were obtained with pre- and post-contrast T1-weighted images in the ipsilateral and contralateral hemispheres. Signal intensity ratios (SIRs) of the ipsilateral and contralateral hemispheres were evaluated on T2-weighted images. After removal of the brain tissues, edema ratios in the ipsilateral and contralateral hemispheres were obtained from wet versus dry brain weights. Data were statistically evaluated by analysis of variance, followed by the Tukey honestly significant difference test to compare the difference in the mean CER of the ipsilateral and contralateral hemispheres, mean SIR on T2-weighted image, and mean edema ratio between each group when overall significance was attained.


RESULTS
In the ipsilateral hemispheres, the difference in the CER between the control group and groups 1 (P=0.004), 2 (P=0.043), and 3 (P=0.008) were statistically significant. The difference in the CERs between the triolein emulsion groups was not statistically significant (P>0.05). The T2-weighted SIRs were significantly different between the control group and groups 1 (P=0.027) and 2 (P=0.004). However, the edema ratios of all doses in the triolein emulsion groups showed no significant differences compared with the control group.


CONCLUSIONS
The minimum dosage of 0.5% triolein emulsion to achieve increased vascular permeability in the hemisphere in cat brains appears to be 3 ml/kg. This minimum dosage of triolein emulsion can be useful for acquiring basic data in further studies of vascular permeability changes in a triolein emulsion model.
Ryu
Ji Hwa
JH
Department of Radiology, Dongrae Paik Hospital, Inje University College of Medicine, Postgraduate School, Pusan National University, Pusan, Korea.
Jeong
Yeon Joo
YJ
Kim
Hak Jin
HJ
Kim
Dong Hyun
DH
Kim
Dong Chan
DC
Kim
Myong Joon
MJ
Kim
Yong Woo
YW
Choi
Seon Hee
SH
Cho
Byung Mann
BM
Moon
Tae Yong
TY
D000704:Analysis of Variance; D000818:Animals; D016477:Artifacts; D002199:Capillary Permeability / Q000187:drug effects*; D002339:Carotid Arteries; D002415:Cats; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D003287:Contrast Media / Q000008:administration & dosage; D004655:Emulsions; D019786:Gadolinium DTPA / Q000008:administration & dosage; D007090:Image Interpretation, Computer-Assisted; D007269:Injections, Intra-Arterial; D008279:Magnetic Resonance Imaging / Q000379:methods*; D014304:Triolein / Q000008:administration & dosage* / Q000494:pharmacology*
D003287:Contrast Media; D004655:Emulsions; D014304:Triolein; D019786:Gadolinium DTPA