title: Feldkamp and circle-and-line cone-beam reconstruction for 3D micro-CT of vascular networks.
abstract: Detailed morphometric knowledge of the microvascular network is needed for studies relating structure to haemodynamic function in organs like the lung. Clinical volumetric CT is limited to millimetre-order spatial resolution. Since evidence suggests that small arterioles (50 to 300 micrometres) dominate pulmonary haemodynamics, we built a micro-CT scanner, capable of imaging excised lungs in 3D with 100 microm resolution, for basic physiology research. The scanner incorporates a micro-focal (3 microm) x-ray source, an xyz theta stage and a CCD-coupled image intensifier detector. We imaged phantoms and contrast-enhanced rat lungs, reconstructing the data with either the Feldkamp or the circle-and-line cone-beam reconstruction algorithm. We present reconstructions using 180 views over 360 degrees for the circular trajectory, augmented with views from a linear scan for the circle-and-line algorithm. Especially for platelike features perpendicular to the rotation axis and remote from the midplane, the circle-and-line algorithm produces superior reconstructions compared with Feldkamp's algorithm. We conclude that the use of nonplanar source trajectories to perform micro-CT on contrast-enhanced, excised lungs can provide data useful for morphometric analysis of vascular trees, currently down to the 130 microm level.
authors.affiliation: Biomedical Engineering Department, Marquette University, Milwaukee, WI 53201, USA.
authors.forename: R H
authors.initials: RH
authors.lastname: Johnson
authors.forename: H
authors.initials: H
authors.lastname: Hu
authors.forename: S T
authors.initials: ST
authors.lastname: Haworth
authors.forename: P S
authors.initials: PS
authors.lastname: Cho
authors.forename: C A
authors.initials: CA
authors.lastname: Dawson
authors.forename: J H
authors.initials: JH
authors.lastname: Linehan
mesh_terms: D000465:Algorithms; D000818:Animals; D004867:Equipment Design; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008168:Lung / Q000000981:diagnostic imaging; D008833:Microcirculation / Q000000981:diagnostic imaging* / Q000502:physiology; D008904:Miniaturization; D008953:Models, Anatomic; D008962:Models, Theoretical; D019047:Phantoms, Imaging; D011652:Pulmonary Circulation / Q000502:physiology*; D051381:Rats; D014057:Tomography, X-Ray Computed / Q000295:instrumentation* / Q000379:methods*