A real-time 3D large field-of-view MRI system with interactive table motion†

Data acquisition using a continuously moving table (CMT) is a new method that is capable of generating three-dimensional (3D) large field-of-view (FOV) MR images. To obtain artifact-free large FOV images or arterial-phase contrast-enhanced large FOV angiograms, a major challenge in CMT is to acquire all of the necessary MR data while matching the table motion to the time-varying images and the physiological dynamics of interest. Rather than restrict CMT techniques to a constant table translation rate and offline reconstruction, here we discuss and implement a more general real-time approach in which the table motion is decoupled from the MR data acquisition. In our implementation, the table moves interactively in response to real-time preview images to ensure optimal imaging conditions. We accomplished this objective by designing and integrating a high-resolution, MR-compatible table position-encoding system to a novel, general-purpose, real-time MR imaging system on a clinical MR scanner. Various technical issues and their practical solutions related to implementation are presented. Experimental results obtained from a lower extremity vascular phantom and five healthy volunteers demonstrate that our proposed approach is robust and able to rapidly and optimally acquire large continuous 3D images by interactively moving the table in response to real-time data reconstruction. We anticipate that the implemented system and its components will be useful for a variety of MR applications, including whole-body screening, angiographic runoff studies, and real-time imaging. © 2006 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 29B: 28–41, 2006