Somatom definition as scanner

Respiratory correlated 4DCT with intravenous contrast injection was performed for all patients on a SOMATOM Definition AS scanner (Siemens Healthineers, Germany). 4DCT image data were phase-sorted into ten phase bins throughout a respiratory cycle based on an external respiratory signal monitored with Real-Time Position Management (RPM, Varian Medical Systems, Palo Alto, CA). The slice separation in each phase of the 4DCT was 2mm. The image resolution in each slice was 512 × 512 pixels and a pixel size of 0.98 × 0.98 mm.
In addition, MR scans in deep inspiration breath-hold without visual guidance were performed for all patients to achieve better visualization of the tumor. The MR images (T1 VIBE with intravenous contrast, T1 FL2D, T2 HASTE, TrueFISP) were acquired in a 1.5T SIEMENS MAGNETOM Avanto scanner (Siemens Healthineers, Germany).

All patients underwent scanning on a Somatom Definition AS scanner (Siemens Healthcare, Erlangen, Germany). Breath-hold training was performed before each examination. All patients were asked to hold their breath at the end of inspiration as long as possible. All injections were performed with an automatic power injector with which 90 ml of contrast medium (Optiray 350 mgI/ml; Mallinckrodt Medical, St. Louis, MO, USA) was injected into the antecubital vein at a rate of 4 ml/s. Contrast-enhanced images were acquired at 90 s after injection. Imaging was performed from the thoracic inlet to the middle portion of the kidneys. Scanning parameters were as follows: 120 kVp, dose modulation ACS (Brilliance-iCT), or 50–100 mA (GE HD750 and Somatom Definition AS), slice thickness 1 mm; matrix 512×512 and standard resolution algorithms.
Various CT scanning criteria have been used to define malignant involvement of lymph nodes, and there is no node size that can reliably determine the stage. In the present study, a short-axis lymph node diameter of ≥1 cm on a CT scan was chosen as the criterion for malignancy due to its wide use in clinical practice (8 (link), 9 (link)).

CT examination was performed on a SOMATOM Definition AS+ scanner (Siemens Healthcare, Erlangen, Germany) with the following parameters: 120 kVp; variable tube current (160-600 mA) depending on the size of the patient; detector collimation, 128×0.6 mm; algorithm, B30; reconstructed thicknesses, 2.0 mm; and increments, 2 mm. After unenhanced scanning, approximately 65-75 mL of iohexol (350 mg I/mL, Omnipaque, GE Healthcare) was injected into the antecubital vein at 2.0-2.5 mL/s via a pump injector. CT scans of the AP and PVP were carried out at 25-35 s and 60-70 s after injection, respectively.

The CT examinations were performed using a Somatom Definition AS+ scanner (Siemens Healthineers, Erlangen, Germany). The CT examinations were obtained with standard exposure parameters (200 effective mAs and 120 kVp; the actual radiation dose was adjusted according to the patient’s body size and shape by automatically modulating the tube current, a detector configuration of 1.5 mm × 16 mm, a table feed of 24 mm per rotation, and a gantry rotation time of 0.5 s. Contrast-enhanced CT scans were performed in the supine position in the portal venous phase with a fixed delay of 70 s after contrast agent injection. By using an autoinjector, 120 mL of nonionic contrast material was intravenously administered at the rate of 3 mL/s. The images were reconstructed with a section thickness and interval of 5 mm.

The preoperative CT examinations were conducted at deep inspiration to avoid the influence of respiratory artifacts. The scanned images were acquired on a Brilliance 40 scanner (Philips Medical Systems, Netherlands) and a Somatom Definition AS scanner (Siemens Medical Systems, Germany). The CT scan parameters and conditions were as follows: 120 kV, 180–220 mAs, 64 × 0.625 mm or 40 × 0.625 mm detector, 0.4 or 1.0 pitch, 512 × 512 matrix, reconstructed at 1.0 mm thickness with 0.7 mm increment, and a standard soft tissue kernel.