Proton magnetic resonance spectroscopic findings of cerebral fat embolism induced by triolein emulsion in cats

Abstract

Background: In experimental studies, embolization of the cerebral hemisphere with triolein emulsion has revealed reversible magnetic resonance imaging (MRI) findings in the subacute stage. Purpose: To investigate the changes in the major metabolites, by proton magnetic resonance spectroscopy (MRS), in a cerebral fat embolism induced by a triolein emulsion. Material and Methods: The internal carotid arteries of 19 cats were injected with a triolein emulsion, and multivoxel MRS was performed 30 min, 1 day, and 7 days later. In the control group, six cats were injected with normal saline. The MR spectra were evaluated for N-acetyl aspartate (NAA), creatine (Cr), and choline (Cho), along with the presence of lipid and lactate. Semiquantitative analyses of NAA/Cr, Cho/Cr, NAA/Cho, and lipid/Cr ratios compared the median values of the ipsilateral metabolite ratios with those of the contralateral side and in the control group for each point in time. Results: The NAA/Cr, Cho/Cr, and NAA/Cho ratios in the ipsilateral cerebral hemisphere of the embolized group after 30 min, 1 day, and 7days were not significantly different from the contralateral hemisphere of the embolized and control groups ( P>0.05). The lipid/Cr ratio in the ipsilateral cerebral hemisphere of the embolized group was significantly higher when compared with the control group ( P=0.012 at 30 min, P=0.001 on day 1, and P=0.018 on day 7). Conclusion: Cerebral fat embolism induced by a triolein emulsion resulted in no significant change in the major metabolites of the brain in the acute stage, except for an elevated lipid/Cr ratio, which suggests the absence of any significant hypoxic-ischemic changes in the lesions embolized using a fat emulsion.