Coronary arteries: breath-hold MR angiography.

Edelman, Robert R.; Manning, Warren J.; Burstein, Deborah; Paulin, Sven

doi:10.1148/radiology.181.3.1947074

Cited by 344 publications

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“…Acquisition of the images during an end-expiratory breath hold is commonly employed to minimize respiratory artifacts, while electrocardiography (ECG) gating can effectively freeze cardiac motion. Edelman and Manning (1,2) were the first to describe breath-held two-dimensional (2D) CMRA acquired during mid-diastole, using an ECGgated segmented k-space gradient echo sequence. The use of newer, faster acquisition schemes that minimize arterial blurring, has significantly improved image quality (3,4).…”

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confidence: 99%

Adaptive vessel tracking: Automated computation of vessel trajectories for improved efficiency in 2D coronary MR angiography

Saranathan

Hood

et al. 2001

Magnetic Resonance Imaging

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A new method was investigated for improving the efficiency of ECG-gated coronary magnetic resonance angiography (CMRA) by accurate, automated tracking of the vessel motion over the cardiac cycle. Vessel tracking was implemented on a spiral gradient-echo pulse sequence with sub-millimeter in-plane spatial resolution as well as high image signal to noise ratio. Breath hold 2D CMRA was performed in 18 healthy adult subjects (mean age 46 ؎ 14 years). Imaging efficiency, defined as the percentage of the slices where more than 30 mm of the vessel is visualized, was computed in multi-slice spiral scans with and without vessel tracking. There was a significant improvement in the efficiency of the vessel tracking sequence compared to the multi-slice sequence (56% vs. 32%, P < 0.001). The imaging efficiency increased further when the true motion of the coronary arteries (determined using a cross correlation algorithm) was used for vessel tracking as opposed to a linear model for motion (71% vs. 57%, P < 0.05). The motion of the coronary arteries was generally found to be linear during the systolic phase and nonlinear during the diastolic phase. The use of subject-tailored, auto- CORONARY MAGNETIC RESONANCE Angiography (CMRA) remains challenging due to constraints imposed by respiratory and cardiac motion. Acquisition of the images during an end-expiratory breath hold is commonly employed to minimize respiratory artifacts, while electrocardiography (ECG) gating can effectively freeze cardiac motion. Edelman and Manning (1,2) were the first to describe breath-held two-dimensional (2D) CMRA acquired during mid-diastole, using an ECGgated segmented k-space gradient echo sequence. The use of newer, faster acquisition schemes that minimize arterial blurring, has significantly improved image quality (3,4).The two most commonly employed schemes are the acquisition of the same image plane over the entire cardiac cycle (traditional "cine") and the acquisition, during mid-diastole, of multiple slices with contiguous cardiac phases. However, both these methods require that segments of the coronary artery be constrained within the planes of the prescribed slices and do not make any adjustments to synchronize image acquisition with the actual changing vessel location. Since there is substantial motion of the coronary arteries (on the order of 2 cm or more) during the cardiac cycle, visualization is typically limited to a small fraction (approximately 20% (5)) of the total images acquired in each breath-hold. This implies repeated breath-hold acquisitions to ensure adequate anatomic coverage; however this is often ill tolerated in patients with coronary artery disease (6).In a previous study, Foo et al (7) proposed a method for improving the imaging efficiency called vessel tracking. A preparatory "cine" acquisition on a plane orthogonal to the CMRA imaging plane, where the cross-section of the arteries are depicted, was used to estimate the maximum excursion of the coronary arteries. By assuming a linear vessel motion across the cardia...

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Adaptive vessel tracking: Automated computation of vessel trajectories for improved efficiency in 2D coronary MR angiography

Saranathan

Hood

et al. 2001

Magnetic Resonance Imaging

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“…One of the major limitations of coronary MR angiography (cMRA) is the need to effectively suppress respiratory motion. Breath-hold imaging is one of the protocols used to solve this problem, 3) in addition to freebreathing and 3-dimensional cMRA, 4,5) which result in better image quality than breath-hold imaging.…”

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Diagnostic Accuracy of Three Different Protocols for 3.0T Coronary Magnetic Resonance Angiography

et al. 2016

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SummaryThe usefulness of coronary magnetic resonance angiography (cMRA) has been reported, although the difference in the diagnostic accuracy of different protocols has not been established.We compared conventional coronary angiography (CAG) and cMRA, conducted within 6 months in 24 consecutive patients between September 2012 and July 2014. Three cMRA protocols were examined, cMRA1, free-breathing wholeheart coronary angiography (WHCA) without contrast; cMRA2, free-breathing WHCA with contrast; and cMRA3, breath-hold steady-state free precession with contrast using a 3.0 T scanner. Image quality was graded on a 4-point scale: 1) nonassessable; 2) assessable, fair vessel contrast; 3) assessable, good vessel contrast; and 4) assessable, excellent vessel contrast. Significant narrowing of the coronary arteries was visually assessed.Stenosis was observed in 34 segments, with a prevalence of 10.3%. For cMRA1, cMRA2, and cMRA3, the numbers of assessable segments were 245 (74.2%), 287 (87.0%), and 164 (49.7%), respectively (P < 0.001 by the McNemar test). For assessable segments, the sensitivity, specificity, positive predictive value, and negative predictive value were 89.3%, 99.1%, 92.6%, and 98.6% for cMRA1, 90.0%, 98.1%, 84.4%, and 98.8% for cMRA2, and 76.5%, 93.9%, 59.1%, and 97.1% for cMRA3, respectively. For the assessable segments, the image quality score was better with cMRA2 than with the other two protocols.cMRA is a useful modality to rule out coronary artery disease, especially the cMRA2 protocol, which performed better than the other two protocols. (Int Heart J 2016; 57: 535-540) Key words: Whole-heart coronary angiography, Steady-state free precession, Coronary artery disease X -ray coronary angiography (CAG) is the current gold standard for the assessment of coronary artery disease (CAD), but it carries the risk of complications because it is an invasive procedure. However, magnetic resonance (MR) imaging technology is noninvasive and radiationfree.1) The ability to evaluate the coronary arteries using electrocardiogram (ECG)-gated MR imaging was first reported in 1987;2) however, only the proximal coronary arteries can be evaluated using this method. One of the major limitations of coronary MR angiography (cMRA) is the need to effectively suppress respiratory motion. Breath-hold imaging is one of the protocols used to solve this problem,3) in addition to freebreathing and 3-dimensional cMRA, 4,5) which result in better image quality than breath-hold imaging.Improvements in cMRA image quality have also been achieved by using gradient performance, radiofrequency-receiving coils, and advanced data acquisition techniques. However, whole heart cMRA requires a long acquisition time, whereas in the clinical setting, evaluation of only the main branch or the proximal portion of the coronary artery is sometimes required. 3T MRI has a better signal-to-noise ratio and higher spatial resolution than 1.5T MRI. On the other hand, cMRA is particularly useful for the assessment of coronary arteries. In addition, 3T MR...

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“…Additionally, several studies report improvements in image quality using an FB acquisition. Although coronary artery (21) and DHE (6) pulse sequences differ significantly, the same respiratory gating and correction strategies have been applied using twodimensional (22) and three-dimensional (23) imaging acquisitions, but have not been validated using the identical BH acquisition.…”

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confidence: 99%

Free‐breathing delayed hyperenhanced imaging of the myocardium: A clinical application of real‐time navigator echo imaging

Goldfarb

Shinnar

2006

Magnetic Resonance Imaging

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Purpose:To compare a free-breathing (FB) acquisition with the current standard of breath-holding (BH) in a clinical setting using identical two-dimensional MR pulse sequences for imaging of myocardial delayed hyperenhancement. Materials and Methods:Two-dimensional gadolinium-enhanced images were acquired using FB and BH techniques in 18 subjects to evaluate delayed enhancement of myocardial infarction. The FB acquisition used a navigator echo to monitor the position of the right hemidiaphragm for respiratory gating and correction. Visual analysis using a 16-segment model, quantitative signal difference to noise ratios, and percent left ventricle (LV) viability measurements for the two acquisition types were statistically compared.Results: An excellent agreement between two-dimensional BH and two-dimensional FB acquisitions was found. In one patient, a nontransmural infarct was seen only in the FB images. There were no statistically significant differences in the number of infarcted segments or the measured signal difference to noise ratios (SDNR) between the two methods. Linear regression and Bland Altman analysis of the percentage LV viable myocardium yielded a good fit and narrow limits of agreement. Conclusion:An FB navigator echo acquisition can be effectively used in the setting of myocardial delay hyperenhanced imaging. Image quality is similar or superior to that of BH imaging. RECENT STUDIES have shown that reversible myocardial dysfunction can be identified using gadoliniumenhanced MRI (1-5). Images of the myocardium are made after a delay of several minutes following T1 shortening contrast agent administration; this technique is often called "delayed hyperenhanced (DHE) imaging." Nonviable tissue is identified as having a slightly higher concentration than viable tissue of an intravenously injected gadolinium contrast agent. An inversion recovery (IR) T1 weighted sequence (6) is used to minimize the signal intensity from viable myocardium. The inversion time (TI) parameter of the pulse sequence, which is the time between the inversion pulse and the acquired data, is adjusted to minimize the image intensity of healthy myocardium. In these images, nonviable myocardium is identified as hyperenhancing regions.To reduce or eliminate artifacts from motion of the heart during the normal respiratory cycle, image data are most commonly acquired over several heartbeats using pulse sequences synchronized with the cardiac cycle and during suspended respiration. Two-dimensional breath-hold (BH) IR spoiled gradient-echo imaging has been validated in animal models and human studies (7-10) and is currently the standard of reference for MR DHE imaging. Since one slice is acquired each BH, this technique requires many breath-holds for the evaluation of the entire left ventricle. Single-slice BH MRI techniques (11,12) have been proposed and adopted to reduce acquisition time, increase image contrast, resolution, or spatial coverage, but BH-DHE techniques remain limited by BH time and patient cooperation.Free-breathing (F...

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Coronary arteries: breath-hold MR angiography.

Cited by 344 publications

References 0 publications

Adaptive vessel tracking: Automated computation of vessel trajectories for improved efficiency in 2D coronary MR angiography

Adaptive vessel tracking: Automated computation of vessel trajectories for improved efficiency in 2D coronary MR angiography

Diagnostic Accuracy of Three Different Protocols for 3.0T Coronary Magnetic Resonance Angiography

Free‐breathing delayed hyperenhanced imaging of the myocardium: A clinical application of real‐time navigator echo imaging

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