Hanpei Zheng1,2, Ming Yang1,2, Yuxi Jia1,2, Lan Zhang1,2, Xiaojie Sun1,2, Yangjing Zhang1,2, Zhuang Nie1,2, Hongying Wu1,2, Xiaohui Zhang3, Ziqiao Lei4,5, Wang Jing6,7. 1. Department of Radiology, Union hospital, Tongji medical college, Huazhong University of Science and Technology, 430022, Wuhan, China. 2. Hubei Province Key Laboratory of Molecular Imaging, 430022, Wuhan, China. 3. Clinical Science, Philips Healthcare Greater China, Wuhan, China. 4. Department of Radiology, Union hospital, Tongji medical college, Huazhong University of Science and Technology, 430022, Wuhan, China. leiziqiaowhxh@163.com. 5. Hubei Province Key Laboratory of Molecular Imaging, 430022, Wuhan, China. leiziqiaowhxh@163.com. 6. Department of Radiology, Union hospital, Tongji medical college, Huazhong University of Science and Technology, 430022, Wuhan, China. xhwangjing@hust.edu.cn. 7. Hubei Province Key Laboratory of Molecular Imaging, 430022, Wuhan, China. xhwangjing@hust.edu.cn.
Abstract
OBJECTIVE: To investigate a novel subtraction method (S-MAR), combing metal artifact reduction (MAR), virtual monochromatic imaging (VMI), and subtraction CT angiography (CTA) to remove the metal artifacts of coils after endovascular embolotherapy of intracranial aneurysms. METHOD: In this retrospective study, 29 patients with 38 coils after endovascular embolotherapy of intracranial aneurysms who underwent cerebral CTA using a dual-layer detector spectral CT were included. Conventional CT images (CI), virtual non-enhanced (VNC) images and VMI ranging from 40 to 120 KeV in steps of 10 were reconstructed. These images were then postprocessed to CIMAR, VMIMAR and VNCMAR with MAR software (O-MAR; Philips Healthcare, Cleveland, OH, USA). The novel subtraction method (S-MAR) was derived from subtraction imaging between VNCMAR and the optimal VMIMAR. Contrast-to-noise (CNR) and Noise(Background) of CI, CIMAR, VMI, and VMIMAR were calculated quantitatively. Two Independent radiologists qualitatively assessed artifacts in all images using coil artifact score (CA score), a 5-point Likert scale. Besides, all coils were divided into two groups (group 1: diameter < 5.0 mm, group 2: diameter ≥ 5.0 mm). Differences between two groups were statistically analyzed. RESULTS: The optimal KeV was 40 KeV. Strong correlations between diameter of coils and the CA score of CI were found (rs = 0.652, P < 0.05). CNR, Noise and CA score were significantly improved by CIMAR and VMIMAR compared with CI (P < 0.05). The S‑MAR showed significantly better performance compared with CI, CIMAR, VMI, and VMIMAR in reducing metal coil artifacts according to the CA score (P < 0.05), especially in group 2. CONCLUSION: The novel S‑MAR proved to be a promising method to reduce coil metal artifacts and elevate the vessel visualization adjacent to coils. It could develop to be widely used in cerebral CTA after coiled aneurysms.
OBJECTIVE: To investigate a novel subtraction method (S-MAR), combing metal artifact reduction (MAR), virtual monochromatic imaging (VMI), and subtraction CT angiography (CTA) to remove the metal artifacts of coils after endovascular embolotherapy of intracranial aneurysms. METHOD: In this retrospective study, 29 patients with 38 coils after endovascular embolotherapy of intracranial aneurysms who underwent cerebral CTA using a dual-layer detector spectral CT were included. Conventional CT images (CI), virtual non-enhanced (VNC) images and VMI ranging from 40 to 120 KeV in steps of 10 were reconstructed. These images were then postprocessed to CIMAR, VMIMAR and VNCMAR with MAR software (O-MAR; Philips Healthcare, Cleveland, OH, USA). The novel subtraction method (S-MAR) was derived from subtraction imaging between VNCMAR and the optimal VMIMAR. Contrast-to-noise (CNR) and Noise(Background) of CI, CIMAR, VMI, and VMIMAR were calculated quantitatively. Two Independent radiologists qualitatively assessed artifacts in all images using coil artifact score (CA score), a 5-point Likert scale. Besides, all coils were divided into two groups (group 1: diameter < 5.0 mm, group 2: diameter ≥ 5.0 mm). Differences between two groups were statistically analyzed. RESULTS: The optimal KeV was 40 KeV. Strong correlations between diameter of coils and the CA score of CI were found (rs = 0.652, P < 0.05). CNR, Noise and CA score were significantly improved by CIMAR and VMIMAR compared with CI (P < 0.05). The S‑MAR showed significantly better performance compared with CI, CIMAR, VMI, and VMIMAR in reducing metal coil artifacts according to the CA score (P < 0.05), especially in group 2. CONCLUSION: The novel S‑MAR proved to be a promising method to reduce coil metal artifacts and elevate the vessel visualization adjacent to coils. It could develop to be widely used in cerebral CTA after coiled aneurysms.
Authors: Felix Eisenhut; Manuel Alexander Schmidt; Alexander Kalik; Tobias Struffert; Julian Feulner; Sven-Martin Schlaffer; Michael Manhart; Arnd Doerfler; Stefan Lang Journal: Diagnostics (Basel) Date: 2022-05-04