Article Figures & Data
Figures
- Fig 1.
Sample projection image from noncollimated full-head C-arm CT acquisition (A) and VOI C-arm CT acquisition (B) with the x-ray source collimated in both horizontal and vertical directions.
- Fig 2.
Sample cross-sections from the ATRACT reconstruction of VOI C-arm CT images from the patient cohort. VOI images show clear visibility of stent and flow-diverter devices and their relationship with the parent artery.
- Fig 3.
Sample cross-section of a C-arm CT acquisition after Pipeline (flow-diverter) embolization of a right ICA aneurysm. A, Cross-section from a secondary reconstruction of a full-head C-arm CT acquisition (also used as a reference image for comparison). B, Cross-section from a standard FDK reconstruction of a VOI C-arm CT acquisition. C, Cross-section from the ATRACT robust reconstruction of the same VOI C-arm CT acquisition. D, Plot of normalized gray-scale values as shown by the colored lines above. Note the information loss from truncation artifacts (see arrows in B and D) recovered with the ATRACT robust reconstruction algorithm in C.
- Fig 4.
Quantitative comparison of image quality of the VOI C-arm CT acquisition by using the Structural Similarity Index Metric. A, Cross-section of a secondary reconstruction from a full-head C-arm CT acquisition. B, Cross-section from a standard FDK reconstruction of a VOI C-arm CT acquisition. C, Corresponding cross-section from an ATRACT reconstruction of the VOI C-arm CT acquisition. D, SSIM map of B and A. E, SSIM map of C and A. Each pixel in D and E represents SSIM values ranging from −1 to +1. A, This image is used as the ground truth reference image; the VOI acquisition is aligned with the full-head acquisition to establish voxel-to-voxel correspondence. Note the improvement in SSIM values corresponding to soft tissue before and after truncation correction as shown by the yellow arrow in D. Bony landmarks and devices have SSIM values close to 1, indicating a strong similarity between the ATRACT 2D VOI reconstruction and the standard FDK full-head reconstruction as shown by arrows in E.
- Fig 5.
Comparison of an absolute and relative dose-area product between the noncollimated full-head C-arm CT acquisition and the collimated VOI C-arm CT acquisition. Note that these measurements are from the same patient for each study. An average reduction of 91.45% in the DAP is observed with the VOI acquisition.
- Fig 6.
VOI C-arm CT images of a basilar tip aneurysm in a 58-year-old woman treated with stent and coils. Contrast-enhanced VOI C-arm CT images were acquired immediately after the stent was deployed. A, Frontal projection of a VOI C-arm CT acquisition. B, ATRACT reconstruction of the same VOI C-arm CT. C, Fluoroscopic overlay of the stent for assistance during coiling. Note that the high-contrast objects like stents are well-visualized with the VOI C-arm CT images. In this particular example, based on the C-arm CT imaging neck coverage was good after the deployment for first stent from the right side, thus avoiding the need for a second stent.
- Fig 7.
Sample C-arm CT cross-sectional images of an ICA aneurysm in a 62-year-old woman treated with the Pipeline (flow-diverter) Embolization Device. A and B, C-arm CT images postdeployment show the malapposition of the flow-diverter device to the parent artery. B, 2D fluoroscopic image shows the balloon angioplasty fully expanding the flow-diverter device. C, Cross-sections from the ATRACT VOI C-arm CT images show improved wall apposition of the flow-diverter device to the parent artery.
