Motion‐corrected simultaneous cardiac positron emission tomography and coronary MR angiography with high acquisition efficiency

Muñoz, Camila; Neji, Radhouène; Cruz, Gastão; Mallia, Andrew; Jeljeli, Sami; Reader, Andrew J.; Botnar, René M.; Prieto, Claudia

doi:10.1002/mrm.26690

Cited by 46 publications

(60 citation statements)

References 43 publications

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“…These results are consistent with previous findings in conventional fat‐suppressed CMRA imaging using the TC+GMD approach at 1.5T and 3T . This indicates that the 2D iNAV‐based TC+GMD approach is robust and reliable for coronary artery imaging, and can be used with different image contrasts and in different sequence configurations.…”

Section: Discussionsupporting

confidence: 91%

“…In this study, we present a framework for respiratory motion‐corrected water/fat CMRA with 100% scan efficiency, which allows shorter and predictable scan time. This approach extends the respiratory motion‐corrected acquisition and reconstruction presented in previous works to a dual‐echo sequence, performing translational plus nonrigid motion correction in order to obtain respiratory motion‐corrected echo images. Then, these echo images are used to obtain water and fat cardiac CMRA images by using a water/fat separation algorithm designed specifically for dual‐echo acquisitions with bipolar readout gradients …”

Section: Discussionmentioning

confidence: 96%

“…After finding the best iNAV for FH and RL translational estimation, three reconstructions were performed for each acquired data set: (1) the proposed translational plus nonrigid respiratory motion‐corrected reconstruction (TC+GMD); (2) 2D translational motion correction only (TC); and (3) without motion correction (NMC) for comparison purposes. The number of respiratory bins for TC+GMD is defined automatically such that there are between 3 and 5 bins; each bin contains approximately the same amount of data and has a maximum bin width of 4.5 mm . All reconstructions, including water/fat separation, were performed offline in MATLAB (The Mathworks, Inc., Natick, MA).…”

Section: Methodsmentioning

confidence: 99%

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Motion corrected water/fat whole‐heart coronary MR angiography with 100% respiratory efficiency

Muñoz

Cruz

Neji

et al. 2019

Magnetic Resonance in Med

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Purpose To develop a framework for respiratory motion‐corrected 3D whole‐heart water/fat coronary MR angiography (CMRA) at 3T with reduced and predictable scan time. Methods A 3D dual‐echo acquisition and respiratory motion‐corrected reconstruction framework for water/fat CMRA imaging was developed. The acquisition sequence integrates a 2D dual‐echo image navigator (iNAV), enabling 100% respiratory scan efficiency. Respiratory motion estimated from both the 2D iNAVs and the 3D data itself is used to produce nonrigid motion‐corrected water/fat CMRA images. A first study to investigate which iNAV (water, fat, in‐phase or out‐of‐phase) provides the best translational motion estimation was performed in 10 healthy subjects. Subsequently, nonrigid motion‐corrected water/fat images were compared to a diaphragmatic navigator gated and tracked water/fat CMRA acquisition. Image quality metrics included visible vessel length and vessel sharpness for both the left anterior descending and right coronary arteries. Results Average vessel sharpness achieved with water, fat, in‐phase and out‐of‐phase iNAVs was 33.8%, 29.6%, 32.2%, and 38.5%, respectively. Out‐of‐phase iNAVs were therefore used for estimating translational respiratory motion for the remainder of the study. No statistically significant differences in vessel length and sharpness ( P > 0.01) were observed between the proposed nonrigid motion correction approach and the reference images, although data acquisition was significantly shorter ( P < 2.6×10 –4 ). Motion correction improved vessel sharpness by 60.4% and vessel length by 47.7%, on average, in water CMRA images in comparison with no motion correction. Conclusion The feasibility of a novel motion‐corrected water/fat CMRA approach has been demonstrated at 3T, producing images comparable to a reference gated acquisition, but in a shorter and predictable scan time.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 96%

Section: Methodsmentioning

confidence: 99%

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Motion corrected water/fat whole‐heart coronary MR angiography with 100% respiratory efficiency

Muñoz

Cruz

Neji

et al. 2019

Magnetic Resonance in Med

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“…Recently, the use of data-driven methods has gained substantial interest for both stand-alone and multi-modality imaging systems [185][186][187][188]. Continuous motion tracking can be used for motion compensation of PET and MR images [189,190]. In thoracic PET imaging, several motion detection techniques have been proposed, through builtin readout of the respiratory position and special radial-self gating sequences, respectively [186,187,191].…”

Section: Motion Compensationmentioning

confidence: 99%

Hybrid Imaging: Instrumentation and Data Processing

et al. 2018

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State-of-the-art patient management frequently requires the use of non-invasive imaging methods to assess the anatomy, function or molecular-biological conditions of patients or study subjects. Such imaging methods can be singular, providing either anatomical or molecular information, or they can be combined, thus, providing "anato-metabolic" information. Hybrid imaging denotes image acquisitions on systems that physically combine complementary imaging modalities for an improved diagnostic accuracy and confidence as well as for increased patient comfort. The physical combination of formerly independent imaging modalities was driven by leading innovators in the field of clinical research and benefited from technological advances that permitted the operation of PET and MR in close physical proximity, for example. This review covers milestones of the development of various hybrid imaging systems for use in clinical practice and small-animal research. Special attention is given to technological advances that helped the adoption of hybrid imaging, as well as to introducing methodological concepts that benefit from the availability of complementary anatomical and biological information, such as new types of image reconstruction and data correction schemes. The ultimate goal of hybrid imaging is to provide useful, complementary and quantitative information during patient work-up. Hybrid imaging also opens the door to multi-parametric assessment of diseases, which will help us better understand the causes of various diseases that currently contribute to a large fraction of healthcare costs.

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“…With the release of Siemens Cardiofreeze tool in the future, new comparisons will be performed between our proposed correction and the Cardiofreeze reconstruction. Several other approaches have been proposed for dual correction of cardiac and respiratory motion that give very promising results using optimized acquisition protocols . Future cardiac PET/MRI studies will evaluate such approaches, however, in this paper we are intending to solve a postacquisition issue.…”

Section: Discussionmentioning

confidence: 99%

Cardiac motion and spillover correction for quantitative PET imaging using dynamic MRI

et al. 2019

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Purpose Cardiac positron emission tomography/magnetic resonance imaging (PET/MRI) acquisition presents novel clinical applications thanks to the combination of viability and metabolic imaging (PET) and functional and structural imaging (MRI). However, the resolution of PET, as well as cardiac and respiratory motion in nongated cardiac imaging acquisition protocols, leads to a reduction in image quality and severe quantitative bias. Respiratory or cardiac motion is customarily addressed with gated reconstruction which results in higher noise. Methods Inspired by a method that has been used in brain PET, a practical correction approach, designed to overcome these existing limitations for quantitative PET imaging, was developed and applied in the context of cardiac PET/MRI. The correction approach for PET data consists of computing the mean density map of each underlying moving region, as obtained with MRI, and translating them to the PET space taking into account the PET spatial and temporal resolution. Using these tissue density maps, the method then constructs a system of linear equations that models the activity recovery and cross‐contamination coefficients, which can be solved for the true activity values. Physical and numerical cardiac phantoms were employed in order to quantify the proposed correction. The full correction pipeline was then used to assess differences in metabolic function between scar and healthy myocardium in eight patients with recent acute myocardial infarction using [11C]‐acetate. Data from ten additional patients, injected with [18F]‐FDG, were used to compare the method to the standard electrocardiography (ECG)‐gated approach. Results The proposed method resulted in better recovery (from 32% to 95% on the simulated phantom model) and less residual activity than the standard approach. Higher signal‐to‐noise and contrast‐to‐noise ratios than ECG‐gating were also witnessed (Signal‐to‐noise ratio (SNR) increased from 2.92 to 5.24, contrast‐to‐noise ratio (CNR) increased from 62.9 to 145.9 when compared to a four‐gate reconstruction). Finally, the relevance of this correction using [11C]‐acetate PET patient data, for which erroneous physiological conclusions could have been made based on the uncorrected data, was established as the correction led to the expected clinical results. Conclusions An efficient and simple method to correct for the quantitative biases in PET measurements caused by cardiac motion has been developed. Validation experiments using phantom and patient data showed improved accuracy and reliability with this approach when compared to simpler strategies such as gated acquisition or optimal regions of interest (ROI).

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Motion‐corrected simultaneous cardiac positron emission tomography and coronary MR angiography with high acquisition efficiency

Cited by 46 publications

References 43 publications

Motion corrected water/fat whole‐heart coronary MR angiography with 100% respiratory efficiency

Motion corrected water/fat whole‐heart coronary MR angiography with 100% respiratory efficiency

Hybrid Imaging: Instrumentation and Data Processing

Cardiac motion and spillover correction for quantitative PET imaging using dynamic MRI

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