Compressed-Sensing Technique Combined with Key-Hole Acquisitions for SNR Enhancement

Abstract

This study proposes a robust method for signal-to-noise ratio (SNR) enhancement necessary for higher spatial resolution imaging in magnetic resonance imaging (MRI) system. The proposed method combines compressed-sensing (CS) technique with key-hole acquisitions. It uses the average of an image acquired by CS and images obtained by key-hole-based acquisitions. This method is called CS averaging with key-hole acquisitions (CSAK). The feasibility of CSAK was evaluated with anthropomorphic phantom studies at 3.0T MRI. SNR and full-width at half-maximum (FWHM) measured from CSAK were compared to those of other methods, such as CS averaging with multiple acquisitions (CSAM), CS averaging with single acquisition (CSAS), conventional data acquisition, and images obtained using Gaussian-smoothing filters. While CSAS required the least scan time, it showed the poorest SNR. CSAM and CSAK showed higher SNR than the conventional data acquisition method with a full k-space. CSAM and CSAK also had spatial resolution performance comparable to that of full k-space-based image. CSAK required the least sampling points. Therefore, it required less scan time than those for CSAM and conventional single full k-space acquisition without averaging. In this study, we found that signal averaging for higher SNR with higher spatial resolution image without increasing the scan time could be achieved by CS-based averaging with key-hole acquisitions. Therefore, the proposed CSAK method could be used for high spatial resolution imaging required for higher SNR in MRI system.