Human coronary arteries: projection angiograms reconstructed from breath-hold two-dimensional MR images.

Abstract

The authors sought to render projection magnetic resonance (MR) angiograms depicting a substantial length of human coronary arteries from sequential breath-hold two-dimensional MR images. Tomographic images of the right and left anterior descending coronary arteries were collected with use of a segmented gradient-recalled sequence that incorporated fat suppression and prone positioning of the patient over a surface coil. After editing the images to eliminate overlapping chamber signals and after realigning the images, a maximum-intensity-projection algorithm was applied to create projection angiograms. For the 10 coronary arteries without severe narrowing, visualized length with projection MR angiography was 109 mm +/- 29 (mean +/- standard error of estimate) versus 121 mm +/- 29 with conventional coronary angiography (ranges, 62-147 mm and 70-180 mm, respectively). At conventional angiography linear regression indicated vessel length to be 1.03 times the length depicted at MR angiography with good correlation (r = .8). Results indicate good correlation between measurements of vessel length with both conventional and MR angiography.

3D motion adapted gating (3D MAG): a new navigator technique for accelerated acquisition of free breathing navigator gated 3D coronary MR-angiography

“…Methods proposed to overcome the effect of respiratory motion may be divided into breath-hold and free breathing approaches. The main handicap of the breath-hold approach is the poor spatial resolution and coverage due to limited breath-holding ability of patients, resulting in short breathhold durations and a limited number of consistently repeated breath-hold positions [30][31][32]. With implementation of the navigator technique to suppress respiratory induced motion artefacts, it became possible to acquire coronary MR-angiography data during free breathing, eliminating the need for active patient cooperation for breath-holding during acquisition [27,30].…”

Prospective adaptive navigator correction for breath‐hold MR coronary angiography

“…This has necessitated substantial slice oversampling (30-50 slices total) and increased scan time to fully evaluate the coronary anatomy ( 1 , 2 , 6). The ability to reformat data sets into projection angiograms (8) is also limited by vessel discontinuity from poor registration. Improved slice registration could overcome these current limitations of breath-hold MRCA, allowing decreased scan time and improved vessel continuity.…”

“…The poor registration of breath-hold MRCA often necessitates slice oversampling to ensure complete coverage of the coronary anatomy for identification of coronary artery stenoses (1, 2 , 6). Improved slice registration has the potential both to decrease total scan time and to improve vessel continuity in reformatted data sets ( 8 ) , as well as to allow multiple-breath-hold imaging sequences (9).…”

Coronary MRI with a Respiratory Feedback Monitor: The 2D Imaging Case

“…6b and 6d). 7 demonstrates a case in which the vessel was misaligned due to inconsistent breath-holds. Figures 7c and 7e demonstrate two contiguous slices that were acquired during two different breath-holds without the RFM.…”