Towards real-time imaging: a literature study on fast imaging by undersampling and smart reconstruction

Abstract

Magnetic Resonance Imaging (MRI) is a non-invasive imaging modality. Unlike Com- puted Tomography (CT), MRI does not use ionizing radiation. Over the years, MRI has improved dramatically in both imaging quality and imaging speed. This revolutionized the field of diagnostic medicine. However, imaging speed, which is essential to many of the MRI applications, remains a ma jor challenge. Imaging speed can be improved by faster collection of data. This can be achieved by using sophisticated non-Cartesian k-space tra- jectories. Popular non-Cartesian schemes include encoding along a radial line or spirals. The point has nearly been reached in which fundamental physical and physiological effects limits the ability to simply encode data more quickly. This fundamental limit has led many researchers to look for methods to reduce the amount of acquired data without degrading image quality. In order to address this issue, various reconstruction techniques have been proposed; in this paper three of them are discussed. Beginning with SENSE(proposed in 1997), followed by k-t BLAST/k-t SENSE, nonlinear inverse reconstruction and ending with a combination of techniques very recently proposed(August 2010). We will also eval- uate two of the three above mentioned techniques with one application i.e. cardiac cine imaging.