Korean J Radiol.  2008 Jun;9(3):205-211. 10.3348/kjr.2008.9.3.205.

The Steroid Effect on the Blood-Ocular Barrier Change Induced by Triolein Emulsion as seen on Contrast-Enhanced MR Images

• Lee JY
• Eun CK
• Kim YW
• Kim HJ
• Jung YJ
• Jae SY
• Cho BM
• Choi SH

• KMID: 1758453
• DOI: http://doi.org/10.3348/kjr.2008.9.3.205

Abstract

OBJECTIVE
The purpose of this study is to evaluate the effect of dexamethasone on the damaged blood-ocular barrier caused by triolein emulsion, using contrast-enhanced MR imaging. MATERIALS AND METHODS: An emulsion of 0.1-mL triolein in 20 mL of saline was infused into the carotid arteries of 32 cats, 12 cats were placed in the treatment group and 18 cats were placed in the Control group. Thirty minutes after the infusion of triolein emulsion, a set of orbital pre- and post-contrast T1-weighted MR images (T1WIs) were obtained. Infusion of 10 mg/kg dexamethasone into the ipsilateral carotid artery of each of the cats in the treatment group cats and 20 mL saline in each of the cats in the control group was given. A second set of pre- and post-contrast orbital T1WIs were obtained three hours following triolein emulsion infusion. Qualitative analysis was performed for the the anterior chamber (AC), the posterior chamber (PC), and in the vitreous humor of the ipsilateral and contralateral eyes. The signal intensity ratios of the ipsilateral eye over the contralateral eye were quantitatively evaluated in the three ocular chambers on the first and second set of T1WIs, and were then statistically compared. RESULTS: Qualitatively, the AC, the PC or the vitreous did not show immediate contrast enhancement on the first and the second set of post-contrast T1WIs. However, the AC and the PC showed delayed contrast enhancement for both groups of cats on the second pre-contrast T1WIs. No enhancement or minimally delayed enhancement was seen for the vitreous humor. Quantitatively, the signal intensity ratios in the PC of the treatment group of cats were statistically lower than the ratios of the control group of cats for the second set of T1WIs (p = 0.037). The AC and vitreous showed no statistically significant difference between the feline treatment group and control group (p > 0.05). CONCLUSION: Contrast-enhanced MR images revealed increased vascular permeability in the PC of the eye after infusion of triolein emulsion. Dexamethasone seems to decrease the breakdown of the blood-aqueous barrier in the PC.

Keyword

Embolism, fat; Orbit, MRI; Blood-ocular barrier; Steroid

MeSH Terms

Animals
Blood-Aqueous Barrier/*drug effects
Blood-Retinal Barrier/*drug effects
Capillary Permeability/drug effects
Cats
Contrast Media
Dexamethasone/*pharmacology
Emulsions
Glucocorticoids/*pharmacology
Image Enhancement
Magnetic Resonance Imaging/*methods
Triolein/*adverse effects

Figure

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  Fig. 1 Orbit MR images (TR/TE, 320/20) of cat in treatment group (A), and of cat in control group (B). Pre-contrast (A1 and B1) and post-contrast (A2 and B2) MR images obtained 30 minutes following triolein emulsion infusion. Pre-contrast (A3 and B3) and post-contrast (A4 and B4) MR images obtained three hours following triolein emulsion infusion. For quantitative analysis, signal intensity was measured with circular region of interest depicted in anterior and posterior chambers and in vitreous humor (A1). Post-contrast MR images obtained 30 minutes following triolein emulsion infusion show no contrast enhancement in anterior chamber, posterior chamber or in vitreous humor (A2 and B2). Pre-contrast MR images obtained three hours following triolein emulsion infusion reveal high signal intensity in anterior chambers of lesion and in contralateral eyes in cats in both groups (A3 and B3), thus representing delayed contrast enhancement. However, hyperintensity is most prominent in ipsilateral eyes of control group cat (B3). Posterior chamber of ipsilateral eyeballs of control group cat show strong, delayed contrast enhancement (long arrow in B3). However, in treatment group cat, posterior chamber of ipsilateral eyeball reveals mild contrast enhancement (long arrow in A3). Minimal, delayed contrast enhancement is seen in posterior vitreous humor of ipsilateral eyes of control group cat (short arrows in B3 and B4).

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