Experimental cerebral fat embolism: embolic effects of triolein and oleic acid depicted by MR imaging and electron microscopy.
OBJECTIVE
In fat embolism, free fatty acid is more toxic than neutral fat in terms of tissue damage. We evaluated the hyperacute embolic effects of triolein and oleic acid in cat brains by using MR imaging and electron microscopy.


METHODS
T2-weighted imaging, diffusion-weighted imaging, and contrast-enhanced T1-weighted imaging were performed in cat brains after the injection of triolein (group 1, n = 8) or oleic acid (group 2, n = 10) into the internal carotid artery. MR images were quantitatively assessed by comparing the signal intensity ratios of the lesions with their counterparts on T2-weighted images, apparent diffusion coefficient (ADC) maps, and contrast-enhanced T1-weighted images. Electron microscopic findings in group 1 were compared with those in group 2.


RESULTS
Qualitatively, MR images revealed two types of lesions. Type 1 lesions were hyperintense on diffusion-weighted images and hypointense on ADC maps. Type 2 lesions were isointense or mildly hyperintense on diffusion-weighted images and isointense on ADC maps. Quantitatively, the signal intensity ratios of type 1 lesions in group 2 specimens were significantly higher on T2-weighted images (P =.013)/(P =.027) and lower on ADC maps compared with those of group 1. Electron microscopy of type 1 lesions in both groups revealed more prominent widening of the perivascular space and swelling of the neural cells in group 2, in contrast to notable endothelial defects in group 1.


CONCLUSIONS
MR and electron microscopic data on cerebral fat embolism induced by either triolein or oleic acid revealed characteristics suggestive of both vasogenic and cytotoxic edema in the hyperacute stage. Tissue damage appeared more severe in the oleic acid group than in the triolein group.
Kim
Hak Jin
HJ
Department of Radiology, Pusan National University College of Medicine, 10 I-Ga, Ami-Dong, Seo-Ku, Pusan 502-739, South Korea.
Lee
Jong Hwa
JH
Lee
Chang Hun
CH
Lee
Suk Hong
SH
Moon
Tae Yong
TY
Cho
Byung Mann
BM
Kim
Hae Kyu
HK
Park
Byung Rae
BR
Chang
Kee Hyun
KH
D000818:Animals; D001921:Brain / Q000473:pathology / Q000648:ultrastructure; D002415:Cats; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging; D004620:Embolism, Fat / Q000139:chemically induced / Q000175:diagnosis* / Q000473:pathology; D020766:Intracranial Embolism / Q000139:chemically induced / Q000175:diagnosis* / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008854:Microscopy, Electron; D019301:Oleic Acid / Q000633:toxicity*; D014304:Triolein / Q000633:toxicity*
D003287:Contrast Media; D014304:Triolein; D019301:Oleic Acid