Practical cone-beam algorithm

Feldkamp, L.A.; Davis, L. C.; Kress, J. W.

doi:10.1364/josaa.1.000612

Cited by 5,498 publications

(3,407 citation statements)

References 11 publications

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“…Images were acquired at isotropic voxel size of 100 mm and reconstructed into 3D images, using a modified cone-beam algorithm. (36) The reconstructed data were expressed in Hounsfield units by calibrating the gray-level values against those of water and air. Mineralized tissue density within the volume of interest was expressed as hydroxyapatite (HA) equivalent density (mg HA cm À3 ), based on the calibration provided by the SB3 bone-mimicking material.…”

Section: Micro-computed Tomography Imagingmentioning

confidence: 99%

Loss of equilibrative nucleoside transporter 1 in mice leads to progressive ectopic mineralization of spinal tissues resembling diffuse idiopathic skeletal hyperostosis in humans

Warraich

Bone

Quinonez

et al. 2012

Journal of Bone and Mineral Research

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Diffuse idiopathic skeletal hyperostosis (DISH) is a noninflammatory spondyloarthropathy, characterized by ectopic calcification of spinal tissues. Symptoms include spine pain and stiffness, and in severe cases dysphagia and spinal cord compression. The etiology of DISH is unknown and there are no specific treatments. Recent studies have suggested a role for purine metabolism in the regulation of biomineralization. Equilibrative nucleoside transporter 1 (ENT1) transfers hydrophilic nucleosides, such as adenosine, across the plasma membrane. In mice lacking ENT1, we observed the development of calcified lesions resembling DISH. By 12 months of age, ENT1 -/-mice exhibited signs of spine stiffness, hind limb dysfunction, and paralysis. Micro-computed tomography (mCT) revealed ectopic mineralization of paraspinal tissues in the cervical-thoracic region at 2 months of age, which extended to the lumbar and caudal regions with advancing age. Energy-dispersive X-ray microanalysis of lesions revealed a high content of calcium and phosphorus with a ratio similar to that of cortical bone. At 12 months of age, histological examination of ENT1 -/-mice revealed large, irregular accumulations of eosinophilic material in paraspinal ligaments and entheses, intervertebral discs, and sternocostal articulations. There was no evidence of mineralization in appendicular joints or blood vessels, indicating specificity for the axial skeleton. Plasma adenosine levels were significantly greater in ENT1 -/-mice than in wild-type, consistent with loss of ENT1-a primary adenosine uptake pathway. There was a significant reduction in the expression of Enpp1, Ank, and Alpl in intervertebral discs from ENT1 -/-mice compared to wild-type mice. Elevated plasma levels of inorganic pyrophosphate in ENT1 -/-mice indicated generalized disruption of pyrophosphate homeostasis. This is the first report of a role for ENT1 in regulating the calcification of soft tissues. Moreover, ENT1 -/-mice may be a useful model for investigating pathogenesis and evaluating therapeutics for the prevention of mineralization in DISH and related disorders. ß

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Section: Micro-computed Tomography Imagingmentioning

confidence: 99%

Loss of equilibrative nucleoside transporter 1 in mice leads to progressive ectopic mineralization of spinal tissues resembling diffuse idiopathic skeletal hyperostosis in humans

Warraich

Bone

Quinonez

et al. 2012

Journal of Bone and Mineral Research

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“…For wider cone angles and for circular scan trajectories the situation is complicated. The reconstruction approach of choice is the so-called Feldkamp algorithm [24]. Its performance varies slightly with the type of implementation, reconstruction times are typically 2-10 min for an image volume of 512 3 .…”

Section: Technology Of C-arm Fd-ct Systemsmentioning

confidence: 99%

“…Image quality will be degraded for areas outside the central plane, and the degradation will increase as a function of the distance to it. The artefacts are generally called cone-beam artefacts [13,24,25]. Work on so-called exact cone-beam reconstruction using complete trajectories is ongoing.…”

Section: Technology Of C-arm Fd-ct Systemsmentioning

confidence: 99%

Flat-detector computed tomography (FD-CT)

2007

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Flat-panel detectors or, synonymously, flat detectors (FDs) have been developed for use in radiography and fluoroscopy with the defined goal to replace standard X-ray film, filmscreen combinations and image intensifiers by an advanced sensor system. FD technology in comparison to X-ray film and image intensifiers offers higher dynamic range, dose reduction, fast digital readout and the possibility for dynamic acquisitions of image series, yet keeping to a compact design. It appeared logical to employ FD designs also for computed tomography (CT) imaging. Respective efforts date back a few years only, but FD-CT has meanwhile become widely accepted for interventional and intraoperative imaging using C-arm systems. FD-CT provides a very efficient way of combining two-dimensional (2D) radiographic or fluoroscopic and 3D CT imaging. In addition, FD technology made its way into a number of dedicated CT scanner developments, such as scanners for the maxillo-facial region or for micro-CT applications. This review focuses on technical and performance issues of FD technology and its full range of applications for CT imaging. A comparison with standard clinical CT is of primary interest. It reveals that FD-CT provides higher spatial resolution, but encompasses a number of disadvantages, such as lower dose efficiency, smaller field of view and lower temporal resolution. FD-CT is not aimed at challenging standard clinical CT as regards to the typical diagnostic examinations; but it has already proven unique for a number of dedicated CT applications, offering distinct practical advantages, above all the availability of immediate CT imaging in the interventional suite or the operating room.

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“…All experiments were acquired, step and shoot, with a 20% energy window around 159 keV in a 64×64 matrix, ROR of 25 mm, and field of view of 31.5 mm. Reconstruction was performed using a HERMES© application program, utilizing filtered back projection and adapted to pinhole SPECT according to the conversion algorithm of Feldkamp [9]. The ramp filter was used as a reconstruction filter with a Butterworth post-reconstruction filter (10.2 cycles per centimeter, order 5).…”

Section: Spect Imagingmentioning

confidence: 99%