Hispeed lx

Visceral and subcutaneous fat were measured from scans obtained using the Imatron C-150 electron-beam, Siemens S4+ Volume Zoom, or General Electric Hi Speed LX CT scanners. We defined VAT as the total adipose tissue enclosed within the abdominal cavity and SAT as the total adipose tissue outside of the abdominal cavity but not within muscle tissue. For this study, participants had six slices obtained from L2 to L5 vertebral spaces (i.e. two at L2-L3, two at L3-L4, two at L4-L5) interrogated for adipose tissue measurements (in cm³). Two analysts independently evaluated each CT using the Medical Imaging Processing Analysis and Visualization Software (MIPAV version 4.1.2). Inter- and intra-rater reliability for the different abdominal CT measurements ranged from 0.92 to 0.99. For our primary analysis, VAT and SAT were defined using the average of two slices obtained at L2–L3 and adjusted for height, as has been done previously.(17 (link)) In a sensitivity analysis, we also included the sum of all 6 slices for those participants who were not missing any slices.

Subclinical CVD was assessed by measurement of calcified plaque in the coronary (CAC) vascular bed with calcium scores calculated as described (16 (link)). Briefly, all cardiac CT examinations were performed on a single-slice helical CT or a four-channel multidetector CT with cardiac gating and capable of 500 ms temporal resolution (HiSpeed LX and LightSpeed QXi with the SmartScore Cardiac scan package; General Electric Medical Systems, Waukesha, WI). After a scout image of the chest, the heart was imaged during suspended respiration at end inspiration. Scan parameters were 3 mm slice thickness, 26 cm display field of view, retrospective cardiac gating, 120 KV, 240 mA, and CT scan pitch adjusted to heart rate for the single-slice system and 2.5 mm slice thickness in four-slice mode, 26 cm display field of view, prospective cardiac gating at 50% of the RR interval, 120 KV, and 240 mA for the multidetector CT.