Somatom definition as 128 slice

After induction of general anaesthesia, the right neck was exposed, and an arterial line was catheterized for proximal pressure monitoring and blood sampling into the right carotid artery. A central venous catheter was then inserted in the right jugular vein. Both groins were exposed and a 10-Fr sheath was placed into the right femoral artery to insert a 7-Fr REBOA catheter (Rescue Balloon®; Tokai Medical Products, Aichi, Japan). The side-arm of the 10-Fr sheath was used for distal pressure monitoring. Acetated Ringer’s solution was infused, targeting a stroke volume variation between 10 and 15%, and a bolus injection was added when the blood pressure dropped. The animals were transferred to a CT scanner (SOMATOM® Definition AS+ [128-slice]; Siemens Healthcare GmbH, Erlangen, Germany) under general anesthesia. A REBOA catheter was placed in the thoracic aorta to maintain balloon position in Zone 1. The REBOA catheter was fixed and the balloon was gradually inflated with close distal pressure monitoring. Total REBOA (100% occlusion) was defined as the complete cessation of distal pulse pressure^{10 (link)}. Percent balloon volume was defined as the percentage of the balloon volume to the maximum balloon volume, which is used as a parameter of the degree of occlusion during P-REBOA.

The CT attenuation was measured on a diagnostic CT scan performed within 6 weeks prior to the biopsy. CT‐guided biopsies performed using a Siemens SOMATOM Definition AS 128 slice CT scanner (Siemens Healthineers, Malvern, PA) using 100–120 kVp and variable tube current. A circular region of interest (ROI) was placed over the region of the lesion that was biopsied, centred around the biopsy tract, taking care to avoid the bony cortex. For fluoroscopically guided biopsies, a musculoskeletal radiologist used anatomic landmarks to identify the expected biopsy tract on CT, and the measurements were taken over the region of the biopsy tract. The mean CT attenuation in Hounsfield units (HU) of the lesion was recorded (Fig. 1A).

All chest CT examinations were conducted in the supine position without contrast and for one full inspiratory breath. In the study, two CT machines were used. The first was a GE Discovery CT750 HD 128 slice (General Electric Healthcare, Boston, MA, USA) with the following typical technical scan parameters: tube current modulation, 219 mAs; tube voltage, 140 kV; spiral pitch factor, 0.9–1.37; matrix, 512 × 512; collimation width, 64 × 0.625. All of the images were reconstructed with a slice thickness and interval of 1 mm.
The second CT machine was a Siemens Somatom Definition AS+ 128 slice (Siemens Healthcare, Erlangen, Germany). The average technical scan parameters were as follows: tube current modulation (mA) with automatic exposure control; tube voltage, 120 kV; spiral pitch factor, 1.2; matrix, 512 × 512; collimation width, 64 × 0.6. All of the images were reconstructed with a slice thickness and interval of 1 mm.
After examining each patient, strict disinfection precautions were followed according to the department’s guidelines.