Volume 89, Issue 5 pp. 1839-1852
RESEARCH ARTICLE

Motion-resolved real-time 4D flow MRI with low-rank and subspace modeling

Aiqi Sun

Aiqi Sun

Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China

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Bo Zhao

Bo Zhao

Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas, USA

Oden Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, Texas, USA

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Yichen Zheng

Yichen Zheng

Beijing PINS Medical Co., Ltd, Beijing, China

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Yuliang Long

Yuliang Long

Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai, China

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Peng Wu

Peng Wu

Philips Healthcare, Shanghai, China

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Bei Wang

Bei Wang

Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China

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Rui Li

Rui Li

Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China

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He Wang

Corresponding Author

He Wang

Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China

Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, China

Correspondence

He Wang, Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China.

Email: [email protected]

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First published: 19 December 2022
Citations: 1

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Aiqi Sun and Bo Zhao contributed equally to this work.

Funding information: China Postdoctoral Science Foundation, Grant/Award Number: 2022M710795; Start-up funds from the University of Texas at Austin, National Natural Science Foundation of China, Grant/Award Numbers: 82271956; 81971583; National Key R&D Program of China, Grant/Award Number: 2018YFC1312900; Natural Science Foundation of Shanghai, Grant/Award Number: 20ZR1406400

Abstract

Purpose

To develop a new motion-resolved real-time four-dimensional (4D) flow MRI method, which enables the quantification and visualization of blood flow velocities with three-directional flow encodings and volumetric coverage without electrocardiogram (ECG) synchronization and respiration control.

Methods

An integrated imaging method is presented for real-time 4D flow MRI, which encompasses data acquisition, image reconstruction, and postprocessing. The proposed method features a specialized continuous ( k , t ) $$ \left(\mathbf{k},t\right) $$ -space acquisition scheme, which collects two sets of data (i.e., training data and imaging data) in an interleaved manner. By exploiting strong spatiotemporal correlation of 4D flow data, it reconstructs time-series images from highly-undersampled ( k , t ) $$ \left(\mathbf{k},t\right) $$ -space measurements with a low-rank and subspace model. Through data-binning-based postprocessing, it constructs a five-dimensional dataset (i.e., x-y-z-cardiac-respiratory), from which respiration-dependent flow information is further analyzed. The proposed method was evaluated in aortic flow imaging experiments with ten healthy subjects and two patients with atrial fibrillation.

Results

The proposed method achieves 2.4 mm isotropic spatial resolution and 34.4 ms temporal resolution for measuring the blood flow of the aorta. For the healthy subjects, it provides flow measurements in good agreement with those from the conventional 4D flow MRI technique. For the patients with atrial fibrillation, it is able to resolve beat-by-beat pathological flow variations, which cannot be obtained from the conventional technique. The postprocessing further provides respiration-dependent flow information.

Conclusion

The proposed method enables high-resolution motion-resolved real-time 4D flow imaging without ECG gating and respiration control. It is able to resolve beat-by-beat blood flow variations as well as respiration-dependent flow information.

CONFLICT OF INTEREST

Yichen Zheng is an employee of Beijing PINS Medical Co. Ltd. Peng Wu is an employee of Philips Healthcare.

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