Quantification and 3D reconstruction of atherosclerotic plaque components in apolipoprotein E knockout mice using ex vivo high-resolution MRI.
OBJECTIVE
To investigate the ability of high-resolution MRI to determine composition and microanatomy of atherosclerosis in mouse aortic root and brachiocephalic artery.


RESULTS
Aortic root and brachiocephalic arteries of apolipoprotein E knockout (apoE-/-) mice fed Western diet for 10, 20, or 30 weeks were imaged ex vivo (11.7 T; 3D multiecho sequence; resolution 47x47x62.5 microm). Using semiautomated histogram-based methods, MRI accurately quantified lipid-rich/necrotic areas in the aortic root (r2=0.84; P<0.001) and brachiocephalic artery (r2=0.90; P<0.001) compared with histology. Similarly, cell-rich caps in aortic roots, quantified by MRI and histology, correlated closely (r2=0.74; P<0.001). Reconstruction of segmented brachiocephalic arteries in 3D provided unique insights into plaque microanatomy and enabled volumetric quantification of plaque and lipid-rich/necrotic core. Between 10 and 30 weeks, 3D measurement identified an 11.6-fold increase in plaque volume (versus 4.1-fold for 2D) and a 21.3-fold increase in plaque lipid-rich/necrotic core volume (versus 6.4-fold for 2D), indicating superior power of 3D quantification.


CONCLUSIONS
Ex-vivo high-resolution 3D MRI accurately quantified lipid-rich/necrotic core and cell-rich cap areas in atherosclerotic lesions in apoE-/- mice. Reconstruction and volumetric quantification of segmented brachiocephalic arteries demonstrated greater sensitivity in detecting changes in plaque size and lipid composition over time than 2D analysis.
McAteer
Martina A
MA
Department of Cardiovascular Medicine, University of Oxford, United Kingdom.
Schneider
Jürgen E
JE
Clarke
Kieran
K
Neubauer
Stefan
S
Channon
Keith M
KM
Choudhury
Robin P
RP
D000818:Animals; D001011:Aorta / Q000473:pathology; D001057:Apolipoproteins E / Q000172:deficiency* / Q000502:physiology; D001161:Arteriosclerosis / Q000473:pathology*; D016122:Brachiocephalic Trunk / Q000473:pathology; D021621:Imaging, Three-Dimensional / Q000379:methods*; D050356:Lipid Metabolism; D008279:Magnetic Resonance Imaging / Q000379:methods*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009336:Necrosis / Q000473:pathology; D015203:Reproducibility of Results
D001057:Apolipoproteins E