Extension of Rapid Phase-Contrast Magnetic Resonance Imaging Using BRISK in Multidirectional Flow

Section: Quantitative Analysis and Exercise Stressmentioning

confidence: 99%

Dobutamine cardiovascular magnetic resonance: A review

Mandapaka

Hundley

2006

“…However, due to doubling the temporal resolution in systole (64 ms), the Sparse Interleaved Referencing PC-MR data maintains high fidelity, even when the VPS is set as high as 8 (Peak velocity underestimation: 16.0% versus 1.7%). This aspect of Sparse Interleaved Referencing PC-MR can be readily combined with FRISK, a fast imaging technique that can at least halve the scan time with comparable accuracy compared with Con PC-MR, to realize breathhold data sampling for cardiovascular PC-MR acquisitions with high fidelity, where breath hold data acquisition is preferred to eliminate respiratory artifacts (24,25).…”

Section: Discussionmentioning

confidence: 99%

Numerical and experimental study of a novel phase contrast magnetic resonance (PC‐MR) imaging technique: Sparse interleaved referencing PC‐MR imaging

Doyle

Rayarao

et al. 2008

Self Cite

Purpose:To use numerical simulation and experimental approaches to introduce a novel phase contrast magnetic resonance (PC-MR) data processing technique termed Sparse Interleaved Referencing PC-MR, with potential to improve accuracy, temporal resolution, and signal-to-noise ratio (SNR) of PC-MR data. Materials and Methods:Computational fluid dynamics data were generated for a two-chamber orifice flow model simulating valvular regurgitation. The numerical results were validated and used to simulate conventional and Sparse Interleaved Referencing PC-MR data acquisitions. Common data sets were processed using conventional and Sparse Interleaved Referencing approaches and quantitative errors in velocity-time waveforms were measured and compared. In vitro phantom jet flow data and in vivo ascending aorta data were acquired and used to simulate Sparse Interleaved Referencing PC-MR. Results:The Sparse Interleaved Referencing PC-MR data showed significantly better representation of the velocity-time waveform in three areas: (i) lower root-mean-square errors (9.0 Ϯ 1.0% versus 24.0 Ϯ 0.2%; P Ͻ 0.005), (ii) simulation of conventionally processed data showed a pattern of peak velocity overestimation, which was experimentally demonstrated in in vitro data, whereas overestimation of peak velocity was dramatically attenuated using Sparse Interleaved Referencing (2.8 Ϯ 0.4% versus 16.9 Ϯ 6.4%, P Ͻ 0.005), and (iii) compared with the conventional scan, an average of 119.4 Ϯ 26.6% (P Ͻ 0.005) SNR was realized in in vitro and in vivo Sparse Interleaved Referencing PC-MR data. Conclusion:Simulation and in vitro/in vivo results show that Sparse Interleaved Referencing PC-MR processed data in pulsatile and jet flow showed higher accuracy, better peak velocity representation, and improved SNR compared with the data processed using the conventional PC-MR method.

“…Our previous studies on the U‐shaped model have shown that BRISK simulation with VPS 5 achieved an excellent representation of the centerline waveform of simulated through‐plane velocity, while in‐plane flow was relatively poorly represented (20). The disagreement in in‐plane velocities in our previous BRISK studies is explicable by the presence of steep temporal and spatial gradients associated with in‐plane circumferential velocities, and the necessity of using higher VPS (VPS >5) to achieve breathhold scan times.…”

Section: Discussionmentioning

confidence: 99%

“…A coarse mesh model with 0.3 million cells and a fine mesh with 0.8 million cells were used in the simulation. The femoral artery bifurcation model and the U‐shaped model were developed and validated in previous studies (20, 21) and detailed model configurations were depicted in the papers.…”

Section: Methodsmentioning

confidence: 99%

Numerical simulation of in vitro pulsatile flow and its study using FRISK, a rapid phase contrast technique

Doyle

Rayarao

et al. 2007

Self Cite

Purpose: To test the potential of a phase contrast magnetic resonance (PC-MR) sparse sampling technique, fragmented regional interpolation segmentation for k-space (FRISK), to capture complex flow features within a breathhold duration by using numerical simulations and experimental approaches. Materials and Methods:Computational fluid dynamics (CFD) data of three models were generated: a two-chamber orifice flow model simulating valvular regurgitation, a femoral artery model, and a U-shaped model simulating the aortic arch. These data were used to simulate conventional and FRISK PC-MR data acquisitions. FRISK parameters can be adapted for different flow fields to capture either high temporal information or complexly varying spatial information with a temporal component or a mixture of both. In vivo PC-MR images on a healthy volunteer were sampled to compare conventional PC-MR with novel FRISK imaging.Results: In our simulations of three representative models, when only the errors from different sampling sequences were considered, FRISK was shown to maintain or even improve data accuracy while cutting the scan time by at least 50% compared to corresponding conventional PC-MR. By adapting the FRISK parameters for flowfields with different features, FRISK was capable of capturing in-plane and through-plane velocity information with excellent detail in approximately 20 heartbeats breathhold duration. The results of the in vivo MR experiment were consistent with the simulation results, showing that breathhold FRISK imaging improved spatial resolution of the data and maintained adequate temporal resolution compared with breathhold conventional imaging.Conclusion: FRISK, a new MRI sampling sequence that sparsely samples data and aligns acquired data during postprocessing, provides a scan time advantage of approximately a factor of 2 compared to conventional scans, and allowed rapid or breathhold scanning while obtaining acceptable accuracy.