Novel technique for addressing streak artifact in gated dual-source MDCT angiography utilizing ECG-editing

Abstract

Streak artifact is an important source of image degradation in computed tomographic imaging. In coronary MDCT angiography, streak artifact from pacemaker leads in the SVC can render segments of the right coronary artery uninterpretable. With current technology in clinical practice, there is no effective way to eliminate streak artifact in coronary MDCT angiography entirely. We propose a technique to minimize the impact of streak artifact in retrospectively gated coronary MDCT angiography by utilizing small shifts in the reconstruction window. In our experience, previously degraded portions of the coronary vasculature were able to be well evaluated using this technique.

Gated Multidetector Computed Tomography

“…With a dual-source 64-channel ct system it was possible to acquire enough projections within 83 ms and a 90° rotation instead of 166 ms and 180° rotation. this increased temporal resolution reduced streak artifacts caused by vessel clips in the vicinity of coronary bypass grafts and enabled visualization of adjacent right coronary artery [8]. in contrast to cardiac imaging data reconstruction where gating is primarily used to "freeze" the cardiac and coronary artery motion, the presented method does not require the patient's heart rate to be linked to the data acquisition.…”

Coronary CT angiography in patients with implanted cardiac devices: initial experience with the metal artefact reduction technique

“…14 Metal artefacts arise from metal elements of the pacemaker or ICD leads and are a result of two processes: a beam hardening phenomenon due to the dense metallic component and the exponential edge-gradient effect due to disparity between the high-density metal and the low-density surrounding tissue. 7 In addition, the extent of artefacts may also be affected by the lead position, the CT acquisition parameters and respiratory and cardiac motion. Therefore, the evaluation of coronary CTA scans of patients with cardiac devices remains challenging.…”

“…4,5 The artefacts are due to scattering, X-ray beam hardening and photon starvation in the shadow of the metal object. 6,7 Single-energy metal artefact reduction (SEMAR) is a new technique developed by Toshiba Medical Systems Corporation on 320-detector CT scanners (Aquilion ONE Vision™; Toshiba Medical Systems Corp., Tokyo, Japan). The algorithm consists of a raw data-and image-based technique; metal artefacts are eliminated and metal-artefact-free CT images are theoretically obtained for non-electrocardiography (ECG)-gated volume data.…”

Cardiac CT: Imaging of and Through Cardiac Devices

“…Pacemaker and implanted ICD leads prevented a valid interpretation of images in up to half of the patients [3]. Streak artifacts arise from metal active elements of pacemaker or ICD leads near the myocardium and are a result of 2 processes—a beam hardening phenomenon due to dense metallic component as well as objects blooming through edge-gradient effect due to disparity between the high-density metal and the low-density surrounding blood [6]. Pacing leads typically have an electrode pair at the tip for sensing and pacing.…”