Time‐resolved contrast‐enhanced carotid imaging using undersampled projection reconstruction acquisition

Abstract

Purpose:To investigate the utility of nonuniform angular spacing of projections in a three-dimensional (3D) hybrid undersampled projection reconstruction (PR) acquisition for contrast-enhanced (CE) time-resolved carotid imaging. Materials and Methods:Carotid CE magnetic resonance angiography (CE-MRA) was performed on seven healthy volunteers using a time-resolved hybrid sequence that combined undersampled PR acquisition in-plane and Cartesian slice encoding through-plane. The undersampling streak artifact comes mainly from the superior-inferior (S/I) direction in carotid imaging and is suppressed by nonuniform distribution of the projections. Phantom and volunteer studies were performed to demonstrate its efficacy. Results:The undersampling streak artifact was significantly suppressed through a nonuniform distribution of the projection angles with more projections aligned along the S/I direction. The hybrid PR sequence combined with nonuniform distribution of the projection angles provided time-resolved images of the carotid arteries with high temporal resolution (two seconds per frame) and high spatial resolution (1.0 ϫ 1.0 ϫ 1.5 mm 3 ) simultaneously. Conclusion:High-resolution dynamic imaging of the carotid arteries is feasible with the use of a hybrid undersampled PR acquisition. Undersampling streak artifact can be suppressed significantly through nonuniform distribution of the projections.

3D Time-Resolved MR Angiography (MRA) of the Carotid Arteries with Time-Resolved Imaging with Stochastic Trajectories: Comparison with 3D Contrast-Enhanced Bolus-Chase MRA and 3D Time-Of-Flight MRA

“…TWIST uses a spiral and pseudostochastic rather than a linear trajectory to traverse a full range of k-space with every iteration, from center to periphery, on the basis of radial distance from the center of kspace (Fig 1), with theoretic advantages in image quality and reduction of artifacts. Although there have been reports in the literature studying different temporal undersampling techniques in this imaging region, 20,21,25 no direct comparisons of the techniques are available.…”

Noninvasive Evaluation of Cerebral Arteriovenous Malformations by 4D-MRA for Preoperative Planning and Postoperative Follow-Up in 56 Patients: Comparison with DSA and Intraoperative Findings

“…[17][18][19][20] Group 1 was imaged by using a matrix of 224 ϫ 178, acquiring 50 dynamic datasets consisting of 140 sections each with a section thickness of 1.4 mm, resulting in a reconstructed voxel size of 1.1 ϫ 1.1 ϫ 1.4 mm 3 . Group 2 was imaged by using a matrix of 232 ϫ 232, acquiring 50 dynamic datasets consisting of 168 sections each with a section thickness of 1.1 mm, resulting in a reconstructed voxel size of 1.1 ϫ 1.1 ϫ 1.1 mm 3 . In group 1, image update took place every 608 ms, whereas in group 2, the temporal resolution was 572 ms.…”

“…The current standard of reference for visualization of cAVMs is DSA because it simultaneously provides high spatial and temporal resolution with clear visualization of feeding arteries and draining veins of these vascular abnormalities. [3][4][5][6][7] However, in addition to possible risks associated with repetitive radiation exposure and application of iodinated contrast agents including allergy and nephrotoxicity, limitations of DSA include risks of bleeding and stroke due to thromboembolism, with a risk for permanent neurologic deficits of 0.1%-1%. [8][9][10][11] Therefore, noninvasive 4D-MRA with vastly accelerated acquisition techniques, which allow both high-temporal and high-spatial-resolution 3D visualization of the intracranial vasculature, may serve as an alternative noninvasive option for the diagnosis and follow-up of cAVMs.…”

Atherosclerotic Peripheral Vascular Disease Symposium II

“…Just as with CTA, rapid advances in MRA technology in the past several years have led to improvements in resolution, anatomic coverage, and speed of image acquisition 14–19. The lack of radiation exposure and the noninvasive nature of MRA offer advantages over CT in many settings 20.…”