Visipaque 270

SCE-CT of the chest, abdomen, and pelvis were acquired using a 64-row dual-layer detector CT scanner (Philips IQon; Philips Healthcare). CT acquisition parameters were 64 × 0.625 mm collimation, kVp 120–140, mAs/slice 150–250, rotation time 0.75 s, reconstruction thickness 2 mm, increment 1 mm, pitch 1.078, FOV 35 cm and matrix 512 × 512. Iodixanol 270 mg/mL (Visipaque® 270; GE Healthcare), or iohexol 300 mg/mL (Omnipaque® 300; GE Healthcare), was injected intravenously in weight-adjusted doses of 2 mL/kg body weight to compensate for differences in distribution volume, with an injection rate of 4 mL/s. A bolus tracking technique was used with an ROI in the descending aorta at the level of Carina to compensate for differences in cardiac output. A threshold of 150 HU was used, and CT was performed after a delay of 15 s for the chest and upper abdomen (late arterial phase), and 65 s for the abdomen (portal venous phase). The mean dose length product (DLP) of CT scans performed on the population was 2104 mGy × cm (CI95% 2064–2144). By spectral separation of the CT signal in the two detector layers, a spectral CT dataset was reconstructed. By weighted addition of the signal of the two layers before reconstruction, a conventional CT dataset was reconstructed, which possesses all the features of a normal single energy CT in terms of dose and image quality.

Conventional angiography was performed with ultrasonography-guided transfemoral approach. A 5-French introducer sheath was placed in the femoral artery. A 5-Fr catheter was advanced to the proximal part of each limb under fluoroscopic guidance. The limb was divided into 3 to 4 segments and digital subtraction angiography was conducted respectively with a non-ionic contrast medium (Visipaque 270; GE Healthcare) injected at a rate of 4 mL/s. The injection duration was 3 to 5 s, and adjusted depending on the distance between the catheter tip and region of interests. The images were obtained at 1 frame/s, and recording time was prolonged in case of slow blood flow.

[⁶⁸Ga]Ga-PSMA-11 was prepared in-house using the commercially purchased precursor PSMA-11 (ABX, Radeberg, Germany). Patients received 1.5 MBq/kg [⁶⁸Ga]Ga-PSMA-11 for IV and ssIA administration, in line with prostate cancer imaging guidelines.¹⁹ (link) IV administration was performed following routine protocol. For ssIA administration, a sheath was placed in either of the groins to secure entrance to the arterial circulation, followed by a routine catheterisation procedure by a board-certified interventional neuroradiologist. Digital subtraction angiography (DSA) and 3D rotational CT was performed using Visipaque 270® (GE Healthcare, USA) as contrast agent, to determine the dominant tumour feeding arteries. After selective catheterisation of the main supplying artery/-ies [⁶⁸Ga]Ga-PSMA-11 was administered by means of a pump, under supervision of a board-certified nuclear medicine physician and radiation protection officer. From the DSA images, data on the exact localization of the catheter(s), tumour enhancement, shunting and/or preferential flow were recorded for each patient.

CTA was performed with a Toshiba Aquilino 64-slice helical CT scanner. Volume CT was routinely performed at 130 mA and 100–120 kVp. Collimation, rotation time and pitch were optimized for the individual CT scanner according to recommendations of the manufacturer. A 90-mL dose of iodinated contrast medium (iopromide, 270 mg of iodine/mL, Visipaque 270; GE Healthcare, Cork, Ireland) was injected at a rate of 4.0 mL/s into an antecubital vein via a 20-gauge catheter, followed by 40 mL of saline solution. CT scanning was triggered by using a bolus-tracking technique, with the region of interest placed in the aortic arch. Image acquisition begins immediately after attenuation reaches the default threshold of 130–150 AU, from the aortic arch to the vertex, in order to have an opacification of the intracranial vascular circulation in the arterial phase. After 5–8 s from the first acquisition we proceeded to a second acquisition, from the vertex to the aortic arch, to have an opacification of the intracranial vascular circulation mainly in the venous phase. The images acquired in this manner allow us to evaluate both arterial and venous well-opacified vasculature and therefore allow us to evaluate both arterial and venous structures.