Hybrid Cone-Beam Tomographic Reconstruction: Incorporation of Prior Anatomical Models to Compensate for Missing Data

• Published in: IEEE transactions on medical imaging Vol. 30; no. 1; pp. 69 - 83
• Main Authors: Sadowsky, Ofri, Junghoon Lee, Sutter, E Grant, Wall, Simon J, Prince, Jerry L, Taylor, Russell H
• Format: Journal Article
• Language: English
• Published: United States IEEE 01.01.2011; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Anatomical atlas; Animals; C-arm; Chimera; Computed tomography; computed tomography (CT); cone-beam reconstruction; Deformable models; Digital filters; Humans; hybrid reconstruction; Image databases; Image intensifiers; Image Processing, Computer-Assisted - methods; Image quality; Image reconstruction; Imaging, Three-Dimensional - methods; Models, Anatomic; Models, Statistical; Phantoms, Imaging; Radiographic Image Enhancement; Radiography; Rendering (computer graphics); Tomography, X-Ray Computed - methods; X-ray imaging
• DOI: 10.1109/TMI.2010.2060491
• ISSN: 0278-0062; 1558-254X

We propose a method for improving the quality of cone-beam tomographic reconstruction done with a C-arm. C-arm scans frequently suffer from incomplete information due to image truncation, limited scan length, or other limitations. Our proposed "hybrid reconstruction" method injects information from a prior anatomical model, derived from a subject-specific computed tomography (CT) or from a statistical database (atlas), where the C-arm X-ray data is missing. This significantly reduces reconstruction artifacts with little loss of true information from the X-ray projections. The methods consist of constructing anatomical models, fast rendering of digitally reconstructed radiograph (DRR) projections of the models, rigid or deformable registration of the model and the X-ray images, and fusion of the DRR and X-ray projections, all prior to a conventional filtered back-projection algorithm. Our experiments, conducted with a mobile image intensifier C-arm, demonstrate visually and quantitatively the contribution of data fusion to image quality, which we assess through comparison to a "ground truth" CT. Importantly, we show that a significantly improved reconstruction can be obtained from a C-arm scan as short as 90 ° by complementing the observed projections with DRRs of two prior models, namely an atlas and a preoperative same-patient CT. The hybrid reconstruction principles are applicable to other types of C-arms as well.