Evaluation of aortic distensibility in wild type and ApoE-knock-out mice at 9.4 T

Material and Methods C57/BL6 and ApoE-/mice (n=6 per group) were evaluated using a horizontal bore 9.4 T MRI animal scanner (Bruker, Karlsruhe, Germany) with a dedicated 2x2 phased-array surface coil. All MRI experiments were performed during general anesthesia using a mixture of isoflurane (2%) and oxygene (98%) applied by a mask covering nose and mouth of the animals. For cine imaging of the aorta a double-gated cine sequence (Intragate® Flash, TR/TE=8.9/2.1 ms, FA=10°, FOV=2x2 cm, matrix=384x384, slice thickness=1 mm) was acquired perpendicular to the ascending aorta. For assessment of cardiac function five consecutive short axis cine sequences were performed covering both ventricles (Intragate® Flash, TR/TE=42.8/1.8 ms, FA=10°, FOV=3x3cm, matrix=256x256, slice thickness= 1mm). AD was defined as the difference of the cross-sectional vessel area at endsystole (AES) and enddiastole (AED) (AD=AES-AED). Left ventricular enddiastolic (LVEDV) and endsystolic (LVESV) volume, stroke volume (SV) and ejection fraction (EF) were analyzed using an image processing software (Osirix). Student ́s T-Test was used for statistical analysis (p<0.05).