Spread spectrum compressed sensing MRI using chirp radio frequency pulses
This work addresses a domain-specific issue for MRI practitioners by offering an incremental improvement in compressed sensing techniques.
The paper tackled the problem of limited modulation intensity and operational inconvenience in spread spectrum compressed sensing MRI by proposing chirp radio frequency pulses for easier control, resulting in more preserved image features compared to conventional methods.
Compressed sensing has shown great potential in reducing data acquisition time in magnetic resonance imaging (MRI). Recently, a spread spectrum compressed sensing MRI method modulates an image with a quadratic phase. It performs better than the conventional compressed sensing MRI with variable density sampling, since the coherence between the sensing and sparsity bases are reduced. However, spread spectrum in that method is implemented via a shim coil which limits its modulation intensity and is not convenient to operate. In this letter, we propose to apply chirp (linear frequency-swept) radio frequency pulses to easily control the spread spectrum. To accelerate the image reconstruction, an alternating direction algorithm is modified by exploiting the complex orthogonality of the quadratic phase encoding. Reconstruction on the acquired data demonstrates that more image features are preserved using the proposed approach than those of conventional CS-MRI.