Coronary Artery Magnetic Resonance Angiography Research Articles

Coronary Artery Magnetic Resonance Angiography Combined with Computed Tomography Angiography in Diagnosis of Coronary Heart Disease by Reconstruction Algorithm.

This research aimed at discussing the diagnosis effect of coronary artery magnetic resonance angiography (MRA) combined with computed tomography (CT) angiography (CTA) based on the back-projection filter reconstruction (BPFR) algorithm in coronary heart disease (CHD), and its role in the diagnosis of coronary artery disease (CAD). Sixty patients with CHD were selected and randomly rolled into group A (undergone MRA examination), group B (undergone CTA examination), and group C (undergone MRA + CTA), with 20 cases in each group. Taking the diagnostic results of coronary angiography as the gold standard, the MRA and CTA images were reconstructed using a BPFR algorithm, and a filter function was added to solve the problem of image sharpness. In addition, the iterative reconstruction algorithm and the Fourier transform analysis method were introduced. As a result, the image clarity and resolution obtained by the BPFR algorithm were better than those obtained by the Fourier transform analytical method and the iterative reconstruction algorithm. The accuracy of group C for the diagnosis of mild coronary stenosis, moderate stenosis, and severe stenosis was 94.02%, 96.13%, and 98.01%, respectively, which was significantly higher than that of group B (87.5%, 90.2%, and 88.4%) and group C (83.4%, 89.1%, and 91.5%) (P < 0.05). The sensitivity and specificity for the diagnosis of noncalcified plaque in group C were 87.9% and 89.2%, respectively, and the sensitivity and specificity for the diagnosis of calcified plaque were 84.5% and 78.4%, respectively, which were significantly higher than those in groups B and C (P < 0.05). In summary, the BPFR algorithm had good denoising and artifact removal effects on coronary MRA and CTA images. The combined detection of reconstructed MRA and CTA images had a high diagnostic value for CHD.

Feasibility of contrast-enhanced coronary artery magnetic resonance angiography using compressed sensing

BackgroundCoronary magnetic resonance angiography (CMRA) is a promising technique for assessing the coronary arteries. However, a disadvantage of CMRA is the comparatively long acquisition time. Compressed sensing (CS) can considerably reduce the scan time. The aim of this study was to verify the feasibility of CS CMRA scanning during the waiting time between contrast injection and late gadolinium enhancement (LGE) scan in a clinical protocol.MethodsFifty clinical patients underwent contrast-enhanced CS CMRA and conventional CMRA on a 3 T CMR scanner. After contrast injection, CS CMRA was scanned during the waiting time for LGE CMR. A conventional CMRA scan was performed after LGE CMR. We assessed acquisition times and coronary artery image quality for each segment on a 4-point scale. Visible vessel length, sharpness and diameter of right (RCA), left anterior descending (LAD), and left circumflex (LCX) coronary arteries were also quantitatively compared among the scans.ResultsAll CS CMRA scans were successfully performed within the LGE waiting time. The median total scan time was 207 s (163, 259 s) for CS and 785 s (698, 975 s) for conventional CMRA (p < 0.001). No significant differences were observed in image quality scores, vessel length measurements, sharpness, and diameter between CS and conventional CMRA.ConclusionsWe could achieve all CS CMRA scans within the LGE waiting time. Contrast-enhanced CS CMRA could considerably shorten the scan time while maintaining image quality compared with conventional CMRA.

Multi-contrast imaging information of coronary artery wall based on magnetic resonance angiography

In order to explore the most suitable image acquisition method for coronary artery wall, the display ability and image quality of segmentation breath-holding target volume acquisition method (the breath-holding method) and real-time navigation whole-hearted acquisition method (the navigation method) of coronary artery magnetic resonance angiography (CMRA) were compared. 26 healthy volunteers were selected to accept the CMRA in 1.5 tunnels magneto-resistance (TMR) equipment by the 2 acquisition methods respectively. The arteries were divided into 9 segments according to the standards of the American Heart Association (AHA). The images were evaluated by 2 magnetic resonance physicians. Satisfaction rate and success rate of each segment of the coronary artery were counted. The results showed that the signal to noise ratio (SNR) and the carrier to noise ratio (CNR) of the images obtained by the breath-holding method were higher than those obtained by the navigation method (P<0.05). Therefore, the segmentation breath-holding target volume acquisition method is proved to have a higher image quality and the simpler and more convenient operations, which is more suitable for the acquisition of positioning images of CMRA.

Diagnostic accuracy of Dixon water fat suppression coronary artery magnetic resonance angiography at 3.0 Tesla

Diagnostic accuracy of Dixon water fat suppression coronary artery magnetic resonance angiography at 3.0 Tesla

Assessment of qualitative and quantitative features in coronary artery MRA

In this paper, an analysis of the coronary trees using magnetic resonance angiography (MRA) is performed. The objective is to estimate how much MRA is capable to provide insights into the vascular network. A qualitative exploration of the MRA volumes with anatomical labelling by experts is first performed, Quantitative vessel features are then manually extracted providing a ground truth which is further compared to a semi-automatic extraction. This evaluation is carried out on 10 datasets of the SSFP MRA sequence and allows getting a more precise view on the current state-of-the- art as well as on future achievements to be done.

Experimental evaluation of dual acceptance window weighting function for right coronary MR angiography at 3.0T

To shorten scanning time and increase the feasibility of experimental results, we performed right coronary artery magnetic resonance angiography (CMRA) at 3.0 T using dual acceptance window weighting function in 25 normal subjects. We examined these subjects using conventional navigator with fixed gating window and 6 dual acceptance window weighted gating (DAWG) sequences with different central weighted ratio (CWR). Compared with the conventional navigator sequence, DAWG sequences with CWRs of 20% and 25% increased the scanning efficiency by 30% and 26% respectively (P<.05), while maintaining good image quality; further the corresponding scanning time decreased from 2.12-1.64 and 1.69 min, respectively (P<.05). However, CWRs less than 15% caused image degradation to some extent. The coronary artery lengths and diameters did not show statistically significant differences between the two techniques (P>.05). Briefly, to avoid the problems caused by low navigator efficiency and to maintain comparable image quality, the weighted gating parameters of 3 mm width central acceptance window and 15 mm width outer acceptance window with CWR between 20% and 25% are recommended for right CMRA at 3 T.

Coronary Artery Magnetic Resonance Angiography (MRA): A Comparison between the Whole-Heart and Volume-Targeted Methods Using a T 2 -Prepared SSFP Sequence

In this study, coronary MRA was performed on 10 healthy volunteers using the whole-heart and volume-targeted scans with comparable imaging parameters. Similar results in the SNR, CNR, and vessel diameter were observed. The depicted length of coronary arteries was longer using the whole-heart scan (whole-heart: RCA/LAD = 13.4 +/- 3.9/10.5 +/- 1.6 cm; volume-targeted: RCA/LAD = 11.0 +/- 2.6/8.7 +/- 1.8 cm). Imaging times for the RCA- (3.8 +/- 1.4 minutes) and LAD-targeted (3.6 +/- 1.3 minutes) are similar, while the time required for one whole-heart scan is significantly longer (12.2 +/- 4.0 minutes). The measured vessel sharpness was higher using the volume-targeted method (whole-heart: RCA/LAD = 0.65 +/- 0.18/0.78 +/- 0.16; volume-targeted: RCA/LAD = 0.84 +/- 0.22/0.90 +/- 0.20). Combination of the whole-heart and volume-targeted methods could be potentially useful in clinical applications of coronary MRA.

Comparison of Gradient-Echo and Steady-State Free Precession for Coronary Artery Magnetic Resonance Angiography Using a Gadolinium-Based Intravascular Contrast Agent

Intravascular contrast agents may offer longer imaging times and better vessel visualization over conventional extravascular agents for magnetic resonance coronary angiography. The purpose of this study was to evaluate the effect of intravascular contrast (B-22956/1) on coronary visualization. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were compared in inversion-recovery (IR)-prepared FLASH (fast low-angle shot) and IR-trueFISP (true fast imaging with steady-state precession) sequences before and after contrast. Numeric simulations were performed to compare blood signals in IR-trueFISP and IR-FLASH sequences. Coronary imaging was performed in 15 swine. Postcontrast CNR was improved 23% with breathhold IR-FLASH and 55% with breathhold IR-trueFISP as compared with precontrast trueFISP. With free-breathing, long TR IR-FLASH provided 131% and 55.8% higher SNR and 132% and 58.7% increased CNR compared with IR-FLASH with shorter TR and IR-trueFISP, respectively. Intravascular contrast agents improve CNR and vessel visualization in coronary magnetic resonance angiography with IR-FLASH and IR-trueFISP.

Three‐dimensional contrast‐enhanced steady‐state free precession for improved catheter‐directed coronary magnetic resonance angiography

To demonstrate the feasibility of three-dimensional thick-partition, contrast-enhanced, catheter-directed coronary artery magnetic resonance angiography (MRA) and test the hypothesis that three-dimensional imaging improves coronary artery background contrast-to-noise ratio (CNR) compared to two-dimensional imaging. Catheters were advanced into the coronary arteries of swine (N = 6) under MR guidance. Three-dimensional coronary MRA was performed after intracoronary injection of a small dose of contrast media using magnetization-prepared steady-state free precession (SSFP) with two thick partitions. For comparison, two magnetization-prepared two-dimensional SSFP scans were also performed, one with no signal averaging and one with two signal averages. All sequences had the same coverage and in-plane spatial resolution. The coronary artery was successfully catheterized in all (6/6) animals. CNR for three-dimensional imaging was 11.1 +/- 1.2 for proximal arterial segments and 4.3 +/- 0.4 for distal segments. Without averaging, two-dimensional imaging CNRs for proximal and distal segments were 5.0 +/- 0.7 and 1.2 +/- 0.2, respectively. With averaging, two-dimensional imaging CNRs for proximal and distal segments were 9.4 +/- 1.5 and 2.9 +/- 0.4, respectively. Three-dimensional imaging showed a statistically significant increase in CNR over all two-dimensional imaging for both proximal and distal segments (P < 0.05). Three-dimensional thick-partition, contrast-enhanced, catheter-directed coronary MRA is feasible and improves CNR over two-dimensional projection imaging.

Coronary artery magnetic resonance angiography.

Coronary magnetic resonance angiography (coronary MRA) continues to advance rapidly from both a technical and clinical perspective. Coronary MRA has benefited directly from improvements in spatial resolution, contrast definition, and advances in motion correction, which have furthered its routine use in evaluating coronary artery bypass grafts and anomalous coronary arteries. Work in refining the techniques for more accurate identification of coronary artery disease (CAD) continues, with advances in navigator-gated and breath-hold motion correction techniques, novel k-space strategies (e.g., spiral and radial k-space filling), development and application of intravascular contrast agents, and imaging at higher field strengths. Ultimately, these developments may lead to the routine application of coronary MRA as a screening tool for CAD. This article reviews the development of coronary MRA, discusses the requirements and tools necessary for optimal visualization of the coronary arteries, and describes the application of coronary MRA to acquired and congenital CAD.

1133-154 Coronary artery magnetic resonance angiography comparison of high field magnetic resonance imaging at 1.5 and 3 tesla

1133-154 Coronary artery magnetic resonance angiography comparison of high field magnetic resonance imaging at 1.5 and 3 tesla

Quelle méthode d’angiographie pour prédire le risque coronaire en 2003 ?: Aspects réglementaires et pratiques de l’utilisation de la coronarographie, de l’IRM et de l’angioscanner

In 2003, risk stratification in coronary heart disease is routinely performed by the results of coronary angiogram, the invasive gold standard angiography. Combined with the left ventricular ejection fraction assessment, the classification in one, two or three vessel disease remain the cornerstone of the revascularization strategy despite well-knowm limitations of this approach. Invasive coronary angiography is a mature technic with recommendations for training program and guidelines for indications. By comparison, the new noninvasive coronary imaging tools, computed tomography (CT) and magnetic resonance (MR) imaging, are just emerging. Coronary artery MR angiography is one of the most challenging areas because of the size and topology of the coronary arteries, as well as cardiac and respiratory motion. Multidetector-row and multisclice spiral computed tomography appear of most value for the detection of coronary artery disease with an excellent negative predictive value for proximal and middle main branches. Together, MR and CT, provide unique information that may predict cardiovascular risk. They identify flow-limiting coronary stenoses and calcified plaques, directly image the atherosclerotic lesions, measure atherosclerotic burden and characterize plaque components. Nevertheless, invasive coronary angiography still remain the first step of percutaneous coronary intervention. Therefore, one of the ultimate goals for the clinicians is the identification of the high-risk patient through a combination of strategies such as assessment of conventional risk factors, blood markers, and imaging. Indifferently to the imaging tool, the treatment should consider a human being and not only a picture.

Quelle méthode d'angiographie pour prédire le risque coronaire en 2003 ? Aspects réglementaires et pratiques de l'utilisation de la coronarographie, de l'IRM et de l'angioscanner

In 2003, risk stratification in coronary heart disease is routinely performed by the results of coronary angiogram, the invasive gold standard angiography. Combined with the left ventricular ejection fraction assessment, the classification in one, two or three vessel disease remain the cornerstone of the revascularization strategy despite well-known limitations of this approach. Invasive coronary angiography is a mature technic with recommendations for training program and guidelines for indications. By comparison, the new noninvasive coronary imaging tools, computed tomography (CT) and magnetic resonance (MR) imaging, are just emerging. Coronary artery MR angiography is one of the most challenging areas because of the size and topology of the coronary arteries, as well as cardiac and respiratory motion. Multidetector-row and multisclice spiral computed tomography appear of most value for the detection of coronary artery disease with an excellent negative predictive value for proximal and middle main branches. Together, MR and CT, provide unique information that may predict cardiovascular risk. They identify flow-limiting coronary stenoses and calcified plaques, directly image the atherosclerotic lesions, measure atherosclerotic burden and characterize plaque components. Nevertheless, invasive coronary angiography still remain the first step of percutaneous coronary intervention. Therefore, one of the ultimate goals for the clinicians is the identification of the high-risk patient through a combination of strategies such as assessment of conventional risk factors, blood markers, and imaging. Indifferently to the imaging tool, the treatment should consider a human being and not only a picture.

690 Free-breathing, three-dimensional, bright blood coronary artery magnetic resonance angiography — Comparison of sequences

690 Free-breathing, three-dimensional, bright blood coronary artery magnetic resonance angiography — Comparison of sequences

Whole-heart steady-state free precession coronary artery magnetic resonance angiography.

Current implementations of coronary artery magnetic resonance angiography (MRA) suffer from limited coverage of the coronary arterial system. Whole-heart coronary MRA was implemented based on a free-breathing steady-state free-precession (SSFP) technique with magnetization preparation. The technique was compared to a similar implementation of conventional, thin-slab coronary MRA in 12 normal volunteers. Three thin-slab volumes were prescribed: 1) a transverse slab, covering the left main (LM) artery and proximal segments of the left anterior ascending (LAD) and left circumflex (LCX) coronary arteries; 2) a double-oblique slab covering the right coronary artery (RCA); and 3) a double-oblique slab covering the proximal and distal segments of the LCX. The whole-heart data set was reformatted in identical orientations. Visible vessel length, vessel sharpness, and vessel diameter were determined and compared separately for each vessel. Whole-heart coronary MRA visualized LM/LAD (11.7 +/- 3.4 cm) and LCX (6.9 +/- 3.6 cm) over a significantly longer distance than the transverse volume (LM/LAD, 6.1 +/- 1.1 cm, P < 0.001; LCX, 4.2 +/- 1.2 cm, P < 0.05). Improvements in visible vessel length for RCA and LCX in the whole-heart approach vs. their respective targeted volumes were not significant. It is concluded that the whole-heart coronary MRA technique improves visible vessel length and facilitates high-quality coronary MRA of the complete coronary artery tree in a single measurement.

Real-time motion correction in navigator-gated free-breathing double-oblique submillimeter 3D right coronary artery magnetic resonance angiography.

The purpose of this study was the investigation of the impact of real-time adaptive motion correction on image quality in navigator-gated, free-breathing, double-oblique three-dimensional (3D) submillimeter right coronary magnetic resonance angiography (MRA). Free-breathing 3D right coronary MRA with real-time navigator technology was performed in 10 healthy adult subjects with an in-plane spatial resolution of 700 x 700 microm. Identical double-oblique coronary MR-angiograms were performed with navigator gating alone and combined navigator gating and real-time adaptive motion correction. Quantitative objective parameters of contrast-to-noise ratio (CNR) and vessel sharpness and subjective image quality scores were compared. Superior vessel sharpness, increased CNR, and superior image quality scores were found with combined navigator gating and real-time adaptive motion correction (vs. navigator gating alone; P < 0.01 for all comparisons). Real-time adaptive motion correction objectively and subjectively improves image quality in 3D navigator-gated free-breathing double-oblique submillimeter right coronary MRA.