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.
Department of Cardiovascular Medicine, University of Oxford, United Kingdom.
Martina A
MA
McAteer
Jürgen E
JE
Schneider
Kieran
K
Clarke
Stefan
S
Neubauer
Keith M
KM
Channon
Robin P
RP
Choudhury
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