Aquilion 64 ct scanner

We selected a patient with an unruptured VA–PICA aneurysm predicted to show impairment of flow in the PICA during endovascular coil embolization. Three-dimensional CT angiography was performed using an Aquilion 64 CT scanner (Toshiba Medical Systems, Tokyo, Japan), and a patient-specific model was built using Digital Imaging and Communications in Medicine (DICOM) data. Next, a 3-dimensional voxel model was built (Case 0; Figure 1). This method is less time consuming compared with the method using an unstructured body-fitted grid, and aneurysm models, with or without modifications, can be easily built. We then built 6 models (Cases 1–6) of various idealized final coil configurations in the modeled aneurysm (Figure 2). Case 1 represented a round coil mass. Case 2 was designed with a stent assist. Cases 3, and 4 were designed with a neck remnant. Cases 5 and 6 incorporated balloon neck remodeling techniques. Case 5 incorporated antegrade neck remodeling with a hyper-compliant balloon, and Case 6 incorporated retrograde neck remodeling with a compliant balloon entering the PICA from the VA. Finally, the outflow to the PICA in each of the models was analyzed using CFD.

I/E CT images were obtained during respiratory pauses at the end of maximum inspiratory effort and expiratory effort using a multiditector Aquilion 64 CT scanner (Toshiba Medical Systems, Tochigi, Japan) with 0.5-mm collimation, a scan time of 500 ms, a peak tube voltage of 120 kVp and autoexposure control.^{9 (link),14 (link)} I/E CT data were transferred to a workstation (SYNAPSE VINCENT; FUJIFILM, Tokyo, Japan), on which 3D lung models were reconstructed and each lung volume measured. ΔLung volume was defined as the value obtained by subtracting expiratory lung volume from inspiratory lung volume.

ECG-gated CT scans were performed on an Aquilion 64 CT scanner (Toshiba Medical Systems Corporation, Tokyo, Japan) or on a Somatom Definition Flash CT scanner (Siemens Healthcare, Erlangen, Germany) with a standardized low-dose scan protocol based on the routine static protocol for the abdomen. The 24-month scans were exclusively acquired on the Somatom Flash scanner. The scans were performed without contrast administration to preclude nephrotoxic effects. Scan parameters were as follows: rotation time 0.4 seconds (Aquilion), 0.3 seconds (Flash); collimation 64×0.5 mm (Aquilion), 2×128×0.6 mm (Flash); slice thickness 1 mm; slice increment 0.5 mm; reconstructed matrix size 512×512 pixels, resulting in submillimeter isotropic datasets. The pitch factor was set automatically based on the heart rate. Tube voltage was set to 120 kV with a tube current time product of 40, 60, or 80 mA.s based on the patient’s body mass index (<20, 20–25, >25 kg/m², respectively), since automated tube current modulation had to be turned off for ECG tracking. This resulted in a dose length product of 962.1±220.1 mGy.cm for a scan length of ~30 cm. Images were acquired during a single breath hold after performing a standard breathing exercise. Retrospective gating was applied to obtain 10 equidistant volumes covering the cardiac cycle.