Laterally Extended Field of View Imaging without Geometric Distortion using Image Stitching in Open-Configuration MRI

Open-configuration MRI for easy patient access causes a restricted imaging field of view and geometric distortion resulting in reduced reliability of the quantitation of tissue segmentation. The method proposed in this study is use of MR image stitching, which is merging divided isocentric images without geometric distortion of the same object through the table moving laterally. This study was performed using an open 0.32 T MRI system. MR imaging with lateral shift of the scanner table was conducted using an AAPM MRI Phantom. The composite image produced through the sequential generation of the same object at different table positions has been generated using the image stitching technique. Image stitching consisted of tile configurations using optimized global registration and then seamlessly blending the aligned tiles. The overall image stitching procedure reduced the geometric distortion of image at off-center regions, and the FOV in the stitched image was extended 40% laterally relative to conventional isocenter image. The maximum distortion value was about 16.8 mm in the conventional image and was reduced to < 1.7 mm after the seamless image stitching procedure. Laterally extended FOV without geometric distortion was successfully acquired using seamless image stitching procedure. These methods are beneficial towards defining tissue segmentation in obese patient with large field of view in open MRI.