Magnetic Resonance Imaging and Histologic Findings of Triolein Emulsion on the Blood–Aqueous Barrier in Cats

Abstract

Abstract: : Purpose: Although the blood–aqueous barrier (BAB) is beneficial physiologically, it acts as an obstacle to drug delivery of chemotherapy. We wished to determine whether a triolein emulsion could alter the permeability of the BAB in cats. Methods: An emulsion of 0.1mL triolein in 20mL of saline was infused into the internal carotid artery in 10 cats (embolic group) and 20mL of normal saline in other 10 cats in a similar way (control group). Pre– and postcontrast MR images were obtained 30 minutes and 3 hours after embolization. Contrast–enhancement ratio (CER = [signal intensity on postcontrast – signal intensity on precontrast]/signal intensity on precontrast) was measured for the quantitative analysis. Statistical analysis was performed by the mixed linear model. After 3hr MR imaging, ocular tissues were obtained and evaluated for electron microscopic examination. Results: In embolic group, the CERs were 0.014 in the anterior chamber and 0.048 in the posterior chamber at 30 minutes, and those at 3 hours were 1.143, and 1.084, respectively, and the difference was statistically significant (p = 0.037, 0.002). Mean CER of posterior chamber at 3 hours of embolic group was also significantly higher than that of control group of 3 hours (0.319 versus 1.084, p = 0.006). Electron microscopic findings revealed pinocytotic intramural fat globules of capillary endothelium. Conclusions: Intra–arterial infusion of triolein emulsion in cats increased the permeability of the BAB and it was confirmed by contrast–enhanced MRI, which could be used as a quantitative, noninvasive method to evaluate permeability of the BAB.

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • microscopy: electron microscopy