Iopamidol

CTPA images were acquired in craniocaudal direction using 16-slice or 64-slice scanners (Siemens Healthcare, Erlangen, Germany) and reconstructed at 1.0 mm slice thickness. Scanning parameters included 80–120 kVp and approximately 200 effective mAs. All patients received 75–100 mL of contrast media that contained 370 mg iodine/mL either in the form of iopromide (Bayer HealthCare, Berlin, Germany) or iopamidol (Bracco Diagnostics, Princeton, NJ, USA). Contrast was administered using a power injector at a rate of 3 mL/s. Image acquisition was timed using bolus tracking on the main pulmonary artery with a threshold attenuation of 80 HU.

Before receiving surgery, all patients underwent contrast-enhanced CT on thyroid with a 16-slice spiral CT scanner (Sensation 16; SIEMENS) or a 64-slice spiral CT scanner (Sensation 64; SIEMENS). After plain CT scanning, a dynamic contrast-enhanced CT scan was performed after intravenous administration of 80–100 mL nonionic contrast material (Iopamidol, 370 mg I/mL, Bracco, Milan, Italy) by using power injection at a rate of 3.5 mL/s followed by saline flush (20 mL). Arterial and venous phase images were obtained at 25 and 60 s, respectively. The slice thickness of the reconstructed image was 1.0 mm. Arterial phase, venous phase, and plain scan CT images were retrieved for image feature extraction. All lesion image parameters (primary tumor maximum diameter, location) were examined and assessed by radiologist Dr. A, and the results were verified by another radiologist Dr. B. The CT images of all target lesions were exported from the Picture Archiving and Communicating System with Digital Imaging and Communications in Medicine format and imported into Radcloud (Huiying Medical Technology Co., Ltd.).

Computed tomography venography images were obtained by a 64- or 256-spiral CT scanner (Brilliance, Philips Healthcare; Revolution, GE Healthcare). The imaging parameters were as follows: 120 kV, automatic milliampere s; matrix 512 × 512, collimation width 64 or 256 × 0.625 mm, rotation time 0.5 s, pitch 0.992:1; contrast (iopamidol, Bracco Diagnostics), 370 mg iodine/ml; 1.5 ml/kg, 5 ml/s. All images were delivered to a postprocessing workstation (Extended Brilliance Workspace, Philips Healthcare). Curve planar reformation was used to show the whole course of the bilateral transverse sinuses. The cross-sectional area of the largest bilateral TSS for each patient was measured (Figure 2). Any transverse sinus with multiple stenoses was measured at the most severe cross-section. The normal areas of the left and right transverse sinuses were measured at the cross-section adjacent to the largest TSS. The percentage of symptomatic-side TSS and average TSS were calculated using the formulas: 1 – (symptomatic-side TSS area/ipsilateral normal area) and 1 – (left TSS area + right TSS area)/(left normal area + right normal area), respectively. The average TSS was calculated to provide a single measure of the average percent TSS for all patients (Zhao et al., 2016 (link)).