Rest period duration of the coronary arteries: Implications for magnetic resonance coronary angiography

Abstract

Magnetic resonance (MR) and computed tomography coronary imaging is susceptible to artifacts caused by motion of the heart. The presence of rest periods during the cardiac and respiratory cycles suggests that images free of motion artifacts could be acquired. In this paper, we studied the rest period (RP) duration of the coronary arteries during a cardiac contraction and a tidal respiratory cycle. We also studied whether three MR motion correction methods could be used to increase the respiratory RP duration. Free breathing x-ray coronary angiograms were acquired in ten patients. The three-dimensional (3D) structure of the coronary arteries was reconstructed from a biplane acquisition using stereo reconstruction methods. The 3D motion of the arterial model was then recovered using an automatic motion tracking algorithm. The motion field was then decomposed into separate cardiac and respiratory components using a cardiac respiratory parametric model. For the proximal-to-middle segments of the right coronary artery (RCA), a cardiac RP (<1 mm 3D displacement) of 76±34 ms was measured at end systole (ES), and 65±42 ms in mid-diastole (MD). The cardiac RP was 80±25 ms at ES and 112±42 ms at MD for the proximal 5 cm of the left coronary tree. At end expiration, the respiratory RP (in percent of the respiratory period) was 26±8% for the RCA and 27±17% for the left coronary tree. Left coronary respiratory RP (<0.5 mm 3D displacement) increased with translation (32% of the respiratory period), rigid body (51%), and affine (79%) motion correction. The RCA respiratory RP using translational (27%) and rigid body (33%) motion correction were not statistically different from each other. Measurements of the cardiac and respiratory rest periods will improve our understanding of the temporal and spatial resolution constraints for coronary imaging.

Displacement and velocity of the coronary arteries: cardiac and respiratory motion

“…The purpose of this study was to measure the three-dimensional (3-D) displacement and velocity of the coronary arteries from free breathing coronary angiograms, and to understand the individual contributions of the cardiac contraction and breathing. This study complements a recently published report on the rest periods of the coronary arteries during the cardiac and respiratory cycles [6].…”

Respiratory motion correction for image-guided cardiac interventions using 3-D echocardiography

“…For example, Shechter et al (2005a) reported that the motion of the left coronary artery was largely rigid-body, whereas that of the right coronary artery was better represented by an affine transform. Therefore, one possible cause for the echo-only technique performing worse away from the left ventricle is that the motion on the right side of the heart has a larger affine component.…”

MR Image-Based Geometric and Hemodynamic Investigation of the Right Coronary Artery with Dynamic Vessel Motion

“…48 Typically it occurs in early to mid diastole and is around 110 ms for the left coronary artery and 65 ms for the RCA. 43 However, in patients with fast heart rates, the end systolic pause may be longer and imaging would best be performed at this time. 50 Although 3D cine coronary angiography has been proposed using radial 3 and Cartesian 5 approaches, the temporal resolution achievable is limited and the rationale behind this approach has largely been to avoid the need for determining a subject-specific trigger time and acquisition window, and to enable averaging over those phases where motion is minimal to improve signal-to-noise ratio.…”