Somatom definition 64

BOLD‐MRI was performed to assess myocardial oxygenation, as we described.22 Briefly, pigs anesthetized with 1% to 2% isoflurane were positioned in the MRI scanner (3 Tesla, Signa Echo Speed; GE Medical Systems, Milwaukee, WI). Scans were performed during suspended respiration before and after a 5‐minute intravenous injection of adenosine (400 μg/kg per minute). The average relaxivity index R2*, a surrogate of myocardial hypoxia, was estimated in regions of interest traced in the septum in each slice, and images analyzed using MATLAB software (version 7.10; The MathWorks, Inc., Natick, MA).22Two days after BOLD‐MRI studies, 64‐slice MDCT (Somatom Definition‐64; Siemens Medical Solution, Forchheim, Germany) studies were performed before and during a 5‐minute intravenous infusion of adenosine (400 μg/kg per minute). The entire LV was scanned throughout the cardiac cycle to obtain cardiac systolic function, end‐diastolic volume (EDV), and LV muscle mass (LVMM).23 Early (E) and late (A) LV filling rates were obtained from the volume/time curve, and myocardial perfusion from time‐attenuation curves obtained from the anterior cardiac wall, as described.24 Images were analyzed with the Analyze software package (Biomedical Imaging Resource; Mayo Clinic, Rochester, MN).

CT scans were obtained on an MDCT scanner (Somatom definition64; Siemens, Erlangen, Germany; LightSpeed VCT XT; GE Healthcare, Milwaukee, WI, USA; or GE optima 660; GE Healthcare, WI, USA). The Siemens scanner was set to the following parameters: detector collimation, 24×1.2 mm; helical pitch, 1.0; section thickness/interval, 3 mm/3 mm; 120 kVp/250 mAs. The GE scanners were set to the following parameters: detector collimation, 64×0.625 mm; helical pitch, 0.984:1; section thickness/interval, 3.75 mm/3.75 mm; 120 kVp/100 to 380 mA. Intravenous contrast was injected at a rate of 3 mL/s with a total volume of 130 mL through the antecubital vein using a mechanical injector. Bolus tracking was not applied, and scanning started 5 minutes after the start of contrast injection. No oral contrast agent was applied. Scanning regularly covered the region from the dome of the liver to the lower urethra. Reformatted images were also created from the source CT dataset using coronal multiplanar reformation (MPR) and maximum intensity projection (MIP). For MPR and MIP images, the slice thickness/interval were 3 mm/3 mm and 10 mm/5 mm, respectively; window width/level was 400/40 and 800/300, respectively.
Standing and sitting height were measured in millimeters with a wall-mounted Harpenden stadiometer before the CT scan.