Lightspeed ultra 16

CT scans were performed by using one of five multidetector units (LightSpeed QX/I, LightSpeed Ultra8, LightSpeed Ultra16, and LightSpeed VCT, GE Medical System, Milwaukee, Wis; Brilliance 40, Philips Medical Systems, Cleveland, Ohio). The parameters for the unenhanced and contrast-enhanced examinations included 0.625–5 mm collimation, pitch of 0.750–0.984, reconstructed section thickness of 3–5 mm, 120 kVp, and 180–240 mAs[11 (link)]. Contrast-enhanced CT scans were obtained after intravenous injection of 120 ml of nonionic contrast medium at a rate of 2.5–3.0 ml/sec by using a power injector. The kidney CT protocol included an unenhanced CT and two-phase contrast-enhanced CT in which images were obtained 30 seconds (arterial phase) and 3 minutes (venous phase) after bolus contrast material injection.

X-ray computer tomography (CT) images were generated for each core section using a GE Yokogawa Medical Systems LightSpeed Ultra 16 (GE Healthcare, 2006) on board the Chikyu during Expedition 337 (Inagaki et al., 2013 (link)). Analytical standards included air (CT number = −1000), water (CT number = 0), and aluminum (2477 < CT number < 2487) in an acrylic core mock-up. For detailed description see Inagaki et al. (2013 (link)).

CT images of the thorax were acquired using the automatic exposure control setting and scan range, and the noise index of was 12.3. CT scans were performed ≤7 days after symptom onset on a helical 64-slice CT GE (Lightspeed Ultra 16, USA; 1.25 mm slice thickness; 1.5 pitch; 120 kVP tube voltage; 100–200 mAs tube current; sagittal and coronal reconstruction thickness, 3 mm with 3-mm intervals) or Siemens (Somatom Definition AS, Germany; 1 mm slice thickness; 1.2 pitch; 120 kVP tube voltage; 100–200 mAs tube current; sagittal and coronal reconstruction thickness, 3 mm with 3-mm intervals; and a sharp reconstruction kernel).

Five specimens were cut out of the outcrops for detailed analysis. To assess the 3D geometry of the burrow and surrounding feather-like structures, one specimen was examined by CT scanning (LightSpeed Ultra16; GE Healthcare Japan Corporation, Japan, 120 kV, 100 mA, slice thickness: 0.625 mm) at the Center for Advanced Marine Core Research (CMCR), at Kochi University in Japan. The CT scanning data were then processed using OsiriX imaging software (Supplementary Fig. S6c,d).

CT images of the liver were obtained with a 16-slice multi-detector CT scanner (Lightspeed Ultra 16, GE Medical Systems, Milwaukee, WI, USA). Nonionic contrast medium (Omnipaque 350, General Electric Healthcare, Princeton, NJ, USA) was administered at a dosage of 1.5 mL/kg (mean total dose, 100 mL; range, 75 to 120 mL) with an injection rate of 3 mL/seconds through a 20-gauge venous cannula placed in the antecubital vein. For triphasic acquisitions, scanning was started with a 10-second scan delay for the hepatic arterial phase (mean, 27.0±1.3 seconds; range, 25 to 30 seconds, after injection of the contrast agent) after the attenuation value of the aorta reached 120 HU. Fifteen seconds after the end point of the hepatic arterial phase (mean, 52.1±1.2 seconds; range, 50 to 55 seconds), the scans for the portovenous phase were acquired. Equilibrium-phase images were acquired 120 seconds (mean, 172.1±1.2 seconds; range, 170 to 175 seconds) after the end of the acquisition of portovenous phase. Whole-liver scanning was completed in 4 to 8 seconds with the patients holding their breath. The CT scanning protocol is shown in Figure 1.