Room: Exhibit Hall | Forum 1
Purpose: Neuro-interventional x-ray guided procedures require high-resolution images to properly guide deployment of interventional devices. The spatial resolution of a new detector on a Canon interventional angiographic system with High-Definition (Hi-Def) modes and FPD modes is investigated.
Methods: The detector consists of standard FPD detector magnification modes (largest FOV of 12 inches and maximum zoom to 2.5 inches) and Hi-Def magnification modes (largest FOV of 3.5 inches and maximum zoom to 1.5 inches) in one unified housing. All modes used to image a line-pair phantom placed against the outer face of the detector. Raw images were acquired using the systemâ€™s digital angiography (DA) mode with the maximum exposure allowed for the small focal spot. An RQA5 phantom was placed in the beamâ€™s path to simulate a spectrum after passing through a human head. The images acquired using the FPD and Hi-Def modes were placed side by side on a computer screen and the highest visible line-pair frequency with no sign of aliasing was assessed.
Results: The images acquired using the Hi-Def zoom modes displayed markedly improved performance over the FPD zoom modes. In the Hi-Def images, 6.3 lp/mm were visible (with corresponding Nyquist frequency of 6.6 lp/mm) while in the FPD images, the maximum spatial frequency that could be clearly distinguished was 2.24 lp/mm (with corresponding Nyquist frequency of 2.6 lp/mm). Rapid electronic switching between all HiDef and FPD modes was demonstrated.
Conclusion: The new detector Hi-Def zoom modes demonstrate vast improvement in spatial resolution over the standard FPD zoom modes. The higher resolution in a smaller ROI may improve visualization of fine details useful in assessing stent deployment and in guiding other neuro-interventional procedures especially during critical parts of an intervention where smaller FOVs are sufficient while rapid mode switching enables instant viewing of the full FOV for reference.
Funding Support, Disclosures, and Conflict of Interest: This work was supported in part by Canon Medical Systems Corporation
High-resolution Imaging, Flat-panel Imagers