Noninvasive Coronary Artery Imaging by Multislice Spiral Computed Tomography. A Novel Approach for a Retrospectively ECG-Gated Reconstruction Technique.

Abstract

oninvasive imaging of the coronary artery has now become available through the recent development of imaging modalities, including high resolution magnetic resonance imaging (MRI) and electron beam computed tomography (EBCT). Nevertheless, there are still limitations in image quality for adequate evaluation of the anatomy of the coronary artery and for the detection and quantification of the coronary artery plaque. More specifically, the spatial resolution of the currently available 1.5 Tesla MRI is up to 1.0 mm, which is theoretically capable of evaluating the major coronary arteries, but it has not gained clinical acceptance because of the low signal-tonoise ratio. 1-3 EBCT gives high temporal resolution and Circulation Journal Vol.67, February 2003 enables quantitative assessment of coronary artery calcium, 4-6 high-grade stenoses 7 and congenital anomalies. 8 However, because of limited spatial resolution related to the limited z axis resolution, it does not allow direct visualization of the coronary artery system and therefore, has not gained widespread clinical use. [9][10][11] During the past years, multislice spiral computed tomography (MSCT), which simultaneously acquires 4 sections, has 0.5 s gantry rotation and up to 125 ms temporal resolution, has been introduced 12,13 and initial results indicate that this technique enables visualization of the major coronary artery branches in normal subjects, 14 as well as coronary artery stents and vessels with significant luminal narrowing distal to the stent. 15 Moreover, a recent study by Schroeder et al demonstrated that MSCT can detect coronary artery soft plaques as validated by intracoronary ultrasound. 16 These preliminary data give substantial optimism for the noninvasive comprehension of coronary artery anatomy in the near future. However, limitations still exist with the reproducibility of images that are satisfactory for Although the excellent spatial resolution of multislice spiral computed tomography (MSCT) enables the coronary arteries to be visualized, its limited temporal resolution results in poor image reproducibility because of cardiac motion artifact (CMA) and hence limits its widespread clinical use. A novel retrospectively ECG-gated reconstruction method has been developed to minimize CMA. In 88 consecutive patients, the scan data were reconstructed using 2 retrospectively ECG-gated reconstruction methods. Method 1: the end of the reconstruction window (250 ms) was positioned at the peak of the P wave on ECG, which corresponded to the end of the slow filling phase during diastole immediately before atrial contraction. Method 2 (conventional method): relative retrospective gating with 50% referred to the R-R interval was performed so that the beginning of the reconstruction window (250 ms) was positioned at the halfway point between the R-R intervals of the heart cycle. The quality of the coronary artery images was evaluated according to the presence or absence of CMA. The assessment was applied to the left main coronary artery (LMCA), th...

Three-Dimensional Visualization of the Coronary Venous System Using Multidetector Row Computed Tomography

“…13 Newer MDCT scanners allow the rapid acquisition of images using thin collimation, thereby generating data sets that yield excellent 3-D and multiplanar renderings that have been shown to be accurate in depicting coronary artery stenosis. [14][15][16][17][18][19] In the present study, we demonstrated for the first time that MDCT could provide accurate and detailed information concerning the CVS and its tributary veins in most patients (91%). Therefore, we believe that it is a useful modality for the assessment of the CVS.…”

“…To measure it precisely, multiplanner reconstruction images should have been used. [14][15][16][17][18][19] However, because of the presence of the phasic changes in the diameter of coronary veins during the cardiac cycle, 22,23 measurement of the actual diameter might be difficult. To determine the maximum diameter of the tributary veins and to assess their use for LV pacing, retrograde venography after occluding the CS lumen by a balloon may be necessary.…”

“…[1][2][3] The CVS has also been used for radiofrequency catheter ablation, 4 mapping, 5 and defibrillation. 6,7 Visualization of the CVS has been attempted by angiography, 8,9 echocardiography 10,11 and electron-beam computed tomography (CT), 12,13 and recently contrast-enhanced multidetector row spiral computed tomography (MDCT) has been used to noninvasively visualize coronary artery stenosis by creating high-quality 3-dimensional (3-D) images, [14][15][16][17][18][19] However, there has not been a study to date that has attempted to analyze the CVS using MDCT, so the aim of the present study was to investigate the applicability and image quality of contrast-enhanced visualization of the CVS by MDCT using retrospective ECG gating. Attention was also focused on the presence and number of coronary veins on the lateral aspect of the left ventricle (LV), which are the optimal sites for placing pacing leads for LV pacing in patients with advanced heart failure.…”

Multidetector-Row Computed Tomography Coronary Angiography Optimization of Image Reconstruction Phase According to the Heart Rate

“…They reported that the image reconstruction phase determined by Method P could consistently avoid the atrial contraction period in each cardiac cycle and could provide much better image quality than the method in which the beginning of the image reconstruction phase was positioned at the midpoint between the RR intervals of the cardiac cycle. 19,20 As previously described, the point at which the reduced ejection period changes into the isovolemic relaxation period is supposed to be near the end point of the T wave. The ventricular movement is expected to be larger at the beginning of the rapid filling period than at the end of the contraction period.…”

Coronary Artery CT Low-Density Plaque Area and Its Ratio to the Whole Area of a Non-Calcified Plaque at the Culprit Lesion in Patients With Unstable and Stable Coronary Artery Disease

“…The end of the reconstruction period was set at the peak of the P wave on the monitoring ECG. 23,24) The reconstructed image data of the CT were transferred to a computer workstation (Ziostation, Amin, Tokyo) for post-processing and were analyzed. After visual inspection of the volume-rendered images, which depicted the gross configuration of the lumen of the coronary artery, coronary artery plaques were inspected carefully on both the axial and curved multiplanar reformatted images, and were used to visually classify coronary lesions.…”