Long Bone Panoramas From Fluoroscopic X-Ray Images

Z. Yaniv, L. Joskowicz
2004 IEEE Transactions on Medical Imaging  
This paper presents a new method for creating a single panoramic image of a long bone from several individual fluoroscopic X-ray images. Panoramic images are useful preoperatively for diagnosis, and intraoperatively for long bone fragment alignment, for making anatomical measurements, and for documenting surgical outcomes. Our method composes individual overlapping images into an undistorted panoramic view that is the equivalent of a single X-ray image with a wide field of view. The
more » ... between the images are established from the graduations of a radiolucent ruler imaged alongside the long bone. Unlike existing methods, ours uses readily available hardware, requires a simple image acquisition protocol with minimal user input, and works with existing fluoroscopic C-arm units without modifications. It is robust and accurate, producing panoramas whose quality and spatial resolution is comparable to that of the individual images. The method has been successfully tested on in-vitro and clinical cases. Current orthopedic practice heavily relies on fluoroscopic X-ray images to perform a variety of surgical procedures such as fracture reduction, joint replacement, osteotomies, and pedicle screw insertion, to name a few. Surgeons use fluoroscopic X-ray images acquired during surgery with a mobile fluoroscopic C-arm to determine the relative position and orientation of bones, implants, and surgical instruments. While inexpensive and readily available, X-ray fluoroscopy has several important limitations, including a narrow field of view, limited resolution and contrast, and geometric distortion. These limitations require the surgeon to frequently acquire images of the surgical situation and to mentally correlate them. They preclude precise evaluation and measurements across images and complicate the placement of long implants. This leads to positioning errors, cumulative radiation exposure to the surgeon, and sub-optimal results in a small but nonnegligible number of cases. While modern X-ray units incorporate geometric distortion correction and contrast enhancement, only a handful address the narrow field of view issue, and only Siemens' is designed for intraoperative use [1], [2], [3] . In this paper, we describe a novel, simple, and inexpensive method for creating a single panoramic image from a few individual fluoroscopic X-ray images. Our method produces an undistorted panoramic view, which is the equivalent of a single X-ray image with a field of view several times wider than that of the individual images by finding correlations between individual overlapping images and composing them (Fig. 1) . It uses standard, readily available, and inexpensive hardware: a video frame grabber, a standard PC, a dewarp grid, and a radiolucent X-ray ruler Manuscript
doi:10.1109/tmi.2003.819931 pmid:14719684 fatcat:xamlicdfxfdvjhn5r3i7mylv5a