Real-time cardiac MRI with radial acquisition and k-space variant reduced-FOV reconstruction

Publication date: Available online 20 July 2018

Source: Magnetic Resonance Imaging

Author(s): Yu Y. Li, Shams Rashid, Yang J. Cheng, William Schapiro, Kathleen Gliganic, Ann-Marie Yamashita, John Tang, Marie Grgas, Michelle Mendez, Elizabeth Haag, Jianing Pang, Bernd Stoeckel, Christianne Leidecker, Jie J. Cao

Abstract

This work aims to demonstrate that radial acquisition with k-space variant reduced-FOV reconstruction can enable real-time cardiac MRI with an affordable computation cost. Due to non-uniform sampling, radial imaging requires k-space variant reconstruction for optimal performance. By converting radial parallel imaging reconstruction into the estimation of correlation functions with a previously-developed correlation imaging framework, Cartesian k-space may be reconstructed point-wisely based on parallel imaging relationship between every Cartesian datum and its neighboring radial samples. Furthermore, reduced-FOV correlation functions may be used to calculate a subset of Cartesian k-space data for image reconstruction within a small region of interest, making it possible to run real-time cardiac MRI with an affordable computation cost. In a stress cardiac test where the subject is imaged during biking with a heart rate of >100 bpm, this k-space variant reduced-FOV reconstruction is demonstrated in reference to several radial imaging techniques including gridding, GROG and SPIRiT. It is found that the k-space variant reconstruction outperforms gridding, GROG and SPIRiT in real-time imaging. The computation cost of reduced-FOV reconstruction is ~2 times higher than that of GROG. The presented work provides a practical solution to real-time cardiac MRI with radial acquisition and k-space variant reduced-FOV reconstruction in clinical settings.

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