Aquilion 64

All patients underwent contrast-enhanced CT before biopsy and/or surgery to evaluate suspected mediastinal tumors. Chest CT examinations were performed with either 320-row detector CT (Toshiba Aquilion ONE, Otawara-shi, Japan), 64-row detector CT (Toshiba Aquilion 64, Otawara-shi, Japan), or 16-row detector CT (Siemens Somatom Sensation 16, Forcheim, Germany) scanners. The acquisition parameters were 0.5 mm, 0.5 mm, and 0.625 mm detector collimation; 120 kVp tube voltage; 0.5 s gantry rotation time; 1 mm, 1 mm, and 1.5 mm reconstructed section thickness; and 0.8 mm, 0.8 mm, and 1 mm reconstruction intervals. All examinations were performed after injecting 60–100 ml (1–1.5 ml/kg) of nonionic intravenous contrast agent (350/100 Omnipaque, GE healthcare, Oslo, Norway), at a rate of 2.5 ml/s via the antecubital vein. The area from the thoracic inlet caudally to include the adrenal glands was scanned. All images were reviewed by a senior radiologist (Ç.U) with more than 10 years of experience in thoracic imaging. She was blinded to the histopathological data to avoid bias. Multiplanar reformatted images were analyzed on a workstation (GE Healthcare, Waukesha, WI, USA) (Figs. 1 and 2).
Fig. 1

The lung extraction and 3D representation of tumor with lung structures

Fig. 2

3D representation of regional segmentation of bronchus, artery, and vessels together with tumor volume

The CT scans were obtained using a helical technique with a 16-detector-row CT scanner (Toshiba Aquilion 16) or a 64-detector-row CT scanner (Toshiba Aquilion 64 and SOMATOM Definition, Siemens). Helical CT scans were obtained from the lung apex to the lung base. For all multi-detector-row CT scans, a section thickness of 1 mm, a helical pitch of 0.9, a reconstruction interval of 1 mm, a reconstruction with a lung kernel (FC51) and a mediastinum kernel (FC13), a tube potential of 120 kVp, and a tube current of 150 mA were used for scanning and image reconstruction. In 258 (80.4%) out of 321 cases, contrast-enhanced CT scans were performed using contrast media (Iopamidol 370; Bayer Yakuhin, Osaka) at 4.0 mL/s (total volume, 1 mL/kg) with a 20-mL saline chaser at 4.0 mL/s.