title: Detector system comparison using relative CNR for specific imaging tasks related to neuro-endovascular image-guided interventions (neuro-EIGIs).
abstract: Neuro-EIGIs require visualization of very small endovascular devices and small vessels. A Microangiographic Fluoroscope (MAF) x-ray detector was developed to improve on the standard flat panel detector's (FPD's) ability to visualize small objects during neuro-EIGIs. To compare the performance of FPD and MAF imaging systems, specific imaging tasks related to those encountered during neuro-EIGIs were used to assess contrast to noise ratio (CNR) of different objects. A bar phantom and a stent were placed at a fixed distance from the x-ray focal spot to mimic a clinical imaging geometry and both objects were imaged by each detector system. Imaging was done without anti-scatter grids and using the same conditions for each system including: the same x-ray beam quality, collimator position, source to imager distance (SID), and source to object distance (SOD). For each object, relative contrasts were found for both imaging systems using the peak and trough signals. The relative noise was found using mean background signal and background noise for varying detector exposures. Next, the CNRs were found for these values for each object imaged and for each imaging system used. A relative CNR metric is defined and used to compare detector imaging performance. The MAF utilizes a temporal filter to reduce the overall image noise. The effects of using this filter with the MAF while imaging the clinical object's CNRs are reported. The relative CNR for the detectors demonstrated that the MAF has superior CNRs for most objects and exposures investigated for this specific imaging task.
authors.affiliation: Toshiba Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY 14214.
authors.forename: Brendan
authors.initials: B
authors.lastname: Loughran
authors.affiliation: Toshiba Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY 14214.
authors.forename: S N
authors.initials: SN
authors.lastname: Swetadri Vasan
authors.affiliation: Toshiba Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY 14214.
authors.forename: Vivek
authors.initials: V
authors.lastname: Singh
authors.affiliation: Toshiba Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY 14214.
authors.forename: Ciprian N
authors.initials: CN
authors.lastname: Ionita
authors.affiliation: Toshiba Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY 14214.
authors.forename: Amit
authors.initials: A
authors.lastname: Jain
authors.affiliation: Toshiba Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY 14214.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Bednarek
authors.affiliation: Toshiba Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY 14214.
authors.forename: Stephen
authors.initials: S
authors.lastname: Rudin
keywords: CNR; MAF; ROI; angiography; fluoroscopy; image metrics; neurovascular interventions; x-ray imaging