Accelerated two-dimensional phase-contrast for cardiovascular MRI using deep learning-based reconstruction with complex difference estimation
Julio A. Oscanoa, Matthew J. Middione, Ali B. Syed, Christopher M. Sandino, Shreyas S. Vasanawala, Daniel B. Ennis
Abstract
Purpose
To develop and validate a deep learning-based reconstruction framework for highly accelerated two-dimensional (2D) phase contrast (PC-MRI) data with accurate and precise quantitative measurements.
Methods
We propose a modified DL‐ESPIRiT reconstruction framework for 2D PC-MRI, comprised of an unrolled neural network architecture with a Complex Difference estimation (CD-DL). CD-DL was trained on 155 fully-sampled 2D PC-MRI pediatric clinical datasets. The fully-sampled data (n=29) was retrospectively undersampled (6-11x) and reconstructed using CD-DL and a parallel imaging and compressed sensing method (PICS). Measurements of peak velocity and total flow were compared to determine the highest acceleration rate that provided accuracy and precision within ±5%. Feasibility of CD-DL was demonstrated on prospectively undersampled datasets acquired in pediatric clinical patients (n=5) and compared to traditional parallel imaging (PI) and PICS.
Results
The retrospective evaluation showed that 9x accelerated 2D PC-MRI images reconstructed with CD-DL provided accuracy and precision (bias, [95$%$ confidence intervals]) within $\pm5%$. CD-DL showed higher accuracy and precision compared to PICS for measurements of peak velocity (2.8% [-2.9, 4.5] vs. 3.9% [-11.0, 4.9]) and total flow (1.8% [-3.9, 3.4] vs. 2.9% [-7.1, 6.9]). The prospective feasibility study showed that CD-DL provided higher accuracy and precision than PICS for measurements of peak velocity and total flow.
Conclusion
In a retrospective evaluation, CD-DL produced quantitative measurements of 2D PC-MRI peak velocity and total flow with ≤5% error in both accuracy and precision for up to 9x acceleration. Clinical feasibility was demonstrated using a prospective clinical deployment of our 8x undersampled acquisition and CD-DL reconstruction in a cohort of pediatric patients.