Mark 5 provis

The clipping protocol of our hospital is for all cerebral aneurysmal patients to have a digital subtraction angiography (DSA) examination before surgical clipping treatment to locate the cerebral aneurysm with precision. The same protocol also applies for the second operation or more rerupture participants in this study. Biplanar intra-arterial DSA was performed using a biplanar flap panel rotational angiography unit (Axiom Artis Zee, Siemens Healthcare) with an image intensifier matrix of 1,024 × 1,024 pixels and a final pixel size of 0.37 mm. Immediately after approaching the femoral artery, a 7-F catheter (Boston Scientific, Mach 1) was inserted into the right or left CCAs near the bifurcation. Posteroanterior and lateral projections were acquired at the level of the carotid bifurcation. A third oblique-angle projection was acquired if overlapping vessels were noted in the first 2 projections. For each projection, 11 mL of nonionic iodinated contrast medium (Omnipaque 350; GE Healthcare, Ireland) was intraarterially injected at a flow rate of 7 mL/s using an automatic injector (Mark V ProVis; Medrad). The location of the aneurysm was discussed by the neuro-radiologist with the family members. Subsequently, the patient was sent to the operating room for the clipping surgery to be carried out under general anesthesia conditions.

Patients were instructed to maintain a normal breathing cycle throughout the study but were asked to follow the operator’s verbal commands for breath-hold during active CT scanning. All patients were imaged in a supine position with their arms raised above their heads. Isocentering of the LA was obtained from the anteroposterior and left lateral X-ray views. In all protocols, the target area of interest (LA and surroundings) was precisely located before the start of the scanning procedure by using a standard dual CT radiograph (a surview) (Figure 2a) and ultralow-dose calcium scoring (Figure 2b). After precise focusing on an LA, a contrast agent tracker was placed in the middle of the LA (Figure 2c) and data acquisition was launched. The total amount of Iomeron 400 contrast (Bracco Imaging S.p.A., Milano, Italy) was calculated individually according to patient weight (0.75 mL/kg). Contrast agent was administered into peripheral veins using the angiographic injection system (Mark-V ProVis, Medrad, Inc., Indianola, PA, USA) with the following modality: (i) 50 mL of contrast agent was injected at 5 mL/s rate; (ii) the rest of the contrast agent was injected at 4 mL/s; (iii) 50 mL of saline was injected at 5 mL/s. The start of the scanning phase was triggered by the tracker threshold set to 110 Hounsfield units (HU) (Figure 2c).