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Erschienen in:
01.03.2015 | Experimental
Quantification of plaque lipids in the aortic root of ApoE-deficient mice by 3D DIXON magnetic resonance imaging in an ex vivo model
Erschienen in: European Radiology | Ausgabe 3/2015
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Objectives
To establish a dedicated protocol for the three-dimensional (3D) quantification of plaque lipids in apolipoprotein E-deficient (apoE−/−) mice using ex vivo MRI.
Methods
ApoE−/− mice were fed a high-fat diet (n = 10) or normal food (n = 10) for 3 months. Subsequently, a 3D FLASH MRI sequence was used to view the anatomy of the aortic root in the isolated hearts, where a 3D double-echo two-excitation pulse sequence (DIXON sequence) was used to selectively image plaque lipids. The vessel wall, lumen and plaque lipid volumes were quantified by MRI and histology for correlation analysis.
Results
DIXON MRI allowed visualisation and accurate quantification of plaque lipids. When comparing the vessel wall, lumen and plaque lipid sizes in the aortic root, Bland–Altman and linear regression analysis revealed a close correlation between MRI results and the histological data both on a slice-by-slice basis and of the volumetric measurements (vessel wall: r
2 = 0.775, p < 0.001; vessel lumen: r
2 = 0.875; p = 0.002; plaque lipid: r
2 = 0.819, p = 0.003).
Conclusions
The combination of 3D FLASH and DIXON-sequence MRI permits an accurate ex vivo assessment of the investigated plaque parameters in the aortic root of mice, particularly the lipid content.
Key Points
• Ex vivo MRI allows high resolution quantification of plaque parameters in mice
• DIXON MRI enables visualisation of plaque lipids in the aortic root of mice
• A close correlation between histology and MRI quantifies plaque parameters
• Preservation of tissue integrity allows additional analysis to be performed
• Short measurement time may permit the translation into in vivo measurements