k‐t accelerated aortic 4D flow <scp>MRI</scp> in under two minutes: Feasibility and impact of resolution, k‐space sampling patterns, and respiratory navigator gating on hemodynamic measurements

Bollache, Emilie; Barker, Alex J.; Dolan, Ryan S.; Carr, James C.; Ooij, Pim van; Ahmadian, Rouzbeh R; Powell, Alex; Collins, Jeremy D.; Geiger, Julia; Markl, Michael

doi:10.1002/mrm.26661

Cited by 44 publications

(36 citation statements)

References 34 publications

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“…Values derived from this technique were found to be highly correlated with those of 2D PC MRI (R 2 = 0.93 for stroke volumes), with some underestimation in Q max in the AAo, superior vena cava, main pulmonary artery, and the left and right pulmonary arteries (−5.1% ± 7.5%) in volunteers when using an acceleration factor of 8 . More recently, Bollache et al explored a 2‐min aortic protocol using no respiratory navigation, k‐t PEAK GRAPPA acceleration (R = 5) with variable sampling patterns, and found underestimation in Q max and v max (Peak velocity, in vitro, −22% to −0.8% underestimation, in vivo [volunteers], −18% to 6.4%; current study : in vitro, −22.5% to −3.7%, in vivo [volunteers], −16.2% to −9.4%) …”

Section: Discussionmentioning

confidence: 99%

Aortic 4D flow MRI in 2 minutes using compressed sensing, respiratory controlled adaptive k‐space reordering, and inline reconstruction

Liliana

Markl

Chow

et al. 2019

Magnetic Resonance in Med

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108

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Purpose To evaluate the accuracy and feasibility of a free‐breathing 4D flow technique using compressed sensing (CS), where 4D flow imaging of the thoracic aorta is performed in 2 min with inline image reconstruction on the MRI scanner in less than 5 min. Methods The 10 in vitro 4D flow MRI scans were performed with different acceleration rates on a pulsatile flow phantom (9 CS acceleration factors [R = 5.4–14.1], 1 generalized autocalibrating partially parallel acquisition [GRAPPA] R = 2). Based on in vitro results, CS‐accelerated 4D flow of the thoracic aorta was acquired in 20 healthy volunteers (38.3 ± 15.2 years old) and 11 patients with aortic disease (61.3 ± 15.1 years) with R = 7.7. A conventional 4D flow scan was acquired with matched spatial coverage and temporal resolution. Results CS depicted similar hemodynamics to conventional 4D flow in vitro, and in vivo, with >70% reduction in scan time (volunteers: 1:52 ± 0:25 versus 7:25 ± 2:35 min). Net flow values were within 3.5% in healthy volunteers, and voxel‐by‐voxel comparison demonstrated good agreement. CS significantly underestimated peak velocities (vmax) and peak flow (Qmax) in both volunteers and patients (volunteers: vmax, −16.2% to −9.4%, Qmax: −11.6% to −2.9%, patients: vmax, −11.2% to −4.0%; Qmax, −10.2% to −5.8%). Conclusion Aortic 4D flow with CS is feasible in a two minute scan with less than 5 min for inline reconstruction. While net flow agreement was excellent, CS with R = 7.7 produced underestimation of Qmax and vmax; however, these were generally within 13% of conventional 4D flow‐derived values. This approach allows 4D flow to be feasible in clinical practice for comprehensive assessment of hemodynamics.

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Section: Discussionmentioning

confidence: 99%

Aortic 4D flow MRI in 2 minutes using compressed sensing, respiratory controlled adaptive k‐space reordering, and inline reconstruction

Liliana

Markl

Chow

et al. 2019

Magnetic Resonance in Med

Self Cite

108

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“…However, the acquisition times in the minute range for a single slice still limit its application, eg for pharmacological stress or first‐pass perfusion imaging. To reduce acquisition times, the application of real‐time (RT) methods not demanding any gating (real time) for the rapid and continuous acquisition of image datasets, such as parallel imaging, 12–14 k‐t acceleration methods, 15–17 and compressed sensing (CS), 18–20 have been suggested and initially evaluated in mice 21 . Radial trajectories have shown favorable properties for RT imaging by their intrinsic low motion artifact level.…”

Section: Introductionmentioning

confidence: 99%

Feasibility of real‐time cardiac MRI in mice using tiny golden angle radial sparse

Metze

Abaei

et al. 2020

NMR in Biomedicine

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Cardiovascular magnetic resonance imaging has proven valuable for the assessment of structural and functional cardiac abnormalities. Even although it is an established imaging method in small animals, the long acquisition times of gated or self-gated techniques still limit its widespread application. In this study, the application of tiny golden angle radial sparse MRI (tyGRASP) for real-time cardiac imaging was tested in 12 constitutive nexilin (Nexn) knock-out (KO) mice, both heterozygous (Het, N = 6) and wild-type (WT, N = 6), and the resulting functional parameters were compared with a well-established self-gating approach. Real-time images were reconstructed for different temporal resolutions of between 16.8 and 79.8 ms per image. The suggested approach was additionally tested for dobutamine stress and qualitative first-pass perfusion imaging. Measurements were repeated twice within 2 weeks for reproducibility assessment. In direct comparison with the high-quality, self-gated technique, the real-time approach did not show any significant differences in global function parameters for acquisition times below 50 ms (rest) and 31.5 ms (stress).Compared with WT, the end-diastolic volume (EDV) and end-systolic volume (ESV) were markedly higher (P < 0.05) and the ejection fraction (EF) was significantly lower in the Het Nexn-KO mice at rest (P < 0.001). For the stress investigation, a clear decrease of EDV and ESV, and an increase in EF, but maintained stroke volume, could be observed in both groups. Combined with ECG-triggering, tyGRASP provided firstpass perfusion data with a temporal resolution of one image per heartbeat, allowing the quantitative assessment of upslope curves in the blood-pool and myocardium.Excellent inter-study reproducibility was achieved in all the functional parameters.The tyGRASP is a valuable real-time MRI technique for mice, which significantly reduces the scan time in preclinical cardiac functional imaging, providing sufficient image quality for deriving accurate functional parameters, and has the potential to investigate real-time and beat-to-beat changes.

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“…Neuhaus et al, who used CS accelerated 4D flow MRI with R = 8, reported a peak flow difference of 4.6 ± 25.2 ml/s. Bollache et al found a peak flow difference of −4.2% to 3% (k‐t acceleration with R = 5), Knobloch et al found reduced peak velocities of 4.9% ± 7% (k‐t PCA with R = 8), and Giese et al found a peak flow underestimation of 5.1% ± 7.5% (k‐t PCA with R = 8). It was not possible to compare PROUD CS with k‐t PCA scans with a higher acceleration factor than 8.…”

Section: Discussionmentioning

confidence: 99%

Pseudo‐spiral sampling and compressed sensing reconstruction provides flexibility of temporal resolution in accelerated aortic 4D flow MRI: A comparison with k‐t principal component analysis

et al. 2020

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Introduction Time‐resolved three‐dimensional phase contrast MRI (4D flow) of aortic blood flow requires acceleration to reduce scan time. Two established techniques for highly accelerated 4D flow MRI are k‐t principal component analysis (k‐t PCA) and compressed sensing (CS), which employ either regular or random k‐space undersampling. The goal of this study was to gain insights into the quantitative differences between k‐t PCA‐ and CS‐derived aortic blood flow, especially for high temporal resolution CS 4D flow MRI. Methods The scan protocol consisted of both k‐t PCA and CS accelerated 4D flow MRI, as well as a 2D flow reference scan through the ascending aorta acquired in 15 subjects. 4D flow scans were accelerated with factor R = 8. For CS accelerated scans, we used a pseudo‐spiral Cartesian sampling scheme, which could additionally be reconstructed at higher temporal resolution, resulting in R = 13. 4D flow data were compared with the 2D flow scan in terms of flow, peak flow and stroke volume. A 3D peak systolic voxel‐wise velocity and wall shear stress (WSS) comparison between k‐t PCA and CS 4D flow was also performed. Results The mean difference in flow/peak flow/stroke volume between the 2D flow scan and the 4D flow CS with R = 8 and R = 13 was 4.2%/9.1%/3.0% and 5.3%/7.1%/1.9%, respectively, whereas for k‐t PCA with R = 8 the difference was 9.7%/25.8%/10.4%. In the voxel‐by‐voxel 4D flow comparison we found 13.6% and 3.5% lower velocity and WSS values of k‐t PCA compared with CS with R = 8, and 15.9% and 5.5% lower velocity and WSS values of k‐t PCA compared with CS with R = 13. Conclusion Pseudo‐spiral accelerated 4D flow acquisitions in combination with CS reconstruction provides a flexible choice of temporal resolution. We showed that our proposed strategy achieves better agreement in flow values with 2D reference scans compared with using k‐t PCA accelerated acquisitions.

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k‐t accelerated aortic 4D flow MRI in under two minutes: Feasibility and impact of resolution, k‐space sampling patterns, and respiratory navigator gating on hemodynamic measurements

Cited by 44 publications

References 34 publications

Aortic 4D flow MRI in 2 minutes using compressed sensing, respiratory controlled adaptive k‐space reordering, and inline reconstruction

Aortic 4D flow MRI in 2 minutes using compressed sensing, respiratory controlled adaptive k‐space reordering, and inline reconstruction

Feasibility of real‐time cardiac MRI in mice using tiny golden angle radial sparse

Pseudo‐spiral sampling and compressed sensing reconstruction provides flexibility of temporal resolution in accelerated aortic 4D flow MRI: A comparison with k‐t principal component analysis

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