Continuously Moving Table MRI in Oncology

Abstract

Magnetic resonance imaging (MRI) with a continuously moving table (CMT) represents a novel method allowing for the seamless acquisition of an extended field-of-view in the z-direction. One option to realize CMT MRI from a technical point of view is based on very fast sequences like echo planar imaging (EPI). Consequently, table translation for signal sampling and image reconstruction can be neglected. The acquisition of different contrasts, however, necessitates table motion correction, either during acquisition or via post-processing. First clinical studies applying fast steady-state imaging already yielded promising results with respect to metastasis detection. Nevertheless, additional equipment has to be installed for table motion and position tracking. In contrast, the subsequently developed sliding multislice (SMS) technique can be implemented without any additional hardware. In clinical studies, the achievable image quality corresponds to stationary sequences. Additionally, the use of SMS for the detection of pulmonary and abdominal metastases appears to be comparable to computed tomography (CT). Due to the relatively short examination times, CMT MRI can be integrated into highly specialized stationary imaging protocols, thus increasing the possibility to combine local staging with thoracoabdominal metastasis screening within one examination. New contrasts like diffusion-weighted imaging (DWI) or Dixon techniques as well as improved workflow including breathing motion compensation and intuitive scout acquisition have already been proposed and will further expand the clinical applications of this technique.