Implementation of a cone‐beam reconstruction algorithm for the single‐circle source orbit with embedded misalignment correction using homogeneous coordinates

Karolczak, Marek; Schaller, Stefan; Engelke, Klaus; Lutz, Andreas; Taubenreuther, Ulrike; Wiesent, K.; Kalender, Willi A.

doi:10.1118/1.1406514

Cited by 58 publications

(36 citation statements)

References 10 publications

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“…Many methods have been proposed for the measurement of the misalignment parameters from the analysis of the acquisition data in cone beam geometry (Beque et al, 2003;Defrise et al, 2008;Noo et al, 2000;von Smekal et al, 2004;Yang et al, 2006). Such parameters can be embedded into the reconstruction process in order to produce misalignment-free reconstructed images (Karolczak et al, 2001).…”

Section: Misalignment Artifactsmentioning

confidence: 99%

High-Resolution CT for Small-Animal Imaging Research

Badea

Panetta²

2014

Comprehensive Biomedical Physics

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Section: Misalignment Artifactsmentioning

confidence: 99%

High-Resolution CT for Small-Animal Imaging Research

Badea

Panetta²

2014

Comprehensive Biomedical Physics

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“…1,7,14 It was reported that 3D images obtained using the cone-beam scanners are inevitably distorted away from the central slice as the single-orbit cone beam geometry does not provide a complete data set. 9,13 These distortions and the associated loss of spatial resolution are particularly evident in samples containing plate-shaped structures, and are minimized by reducing the cone-beam angle. 5,9,13 However, a smaller cone-beam angle has often been found to be associated with lesser number of scanning fields and lower resolution.…”

Section: Introductionmentioning

confidence: 99%

“…9,13 These distortions and the associated loss of spatial resolution are particularly evident in samples containing plate-shaped structures, and are minimized by reducing the cone-beam angle. 5,9,13 However, a smaller cone-beam angle has often been found to be associated with lesser number of scanning fields and lower resolution. This was attributed to the limitation of the distances between the object, X-ray tube, and detectors.…”

Section: Introductionmentioning

confidence: 99%

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The Influence of Center of Rotation on the Assessment of Trabecular Bone Densitometric and Structural Properties

Sheng

Dai

et al. 2008

Ann Biomed Eng

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The center of rotation is a physical location in the microCT scanner, defined by the axis of rotation of the sample stage. This physical location is always well defined during calibration of the instrument and fitted by an appropriate algorithm. However, in real images of limited contrast and with X-ray photon noise, this algorithm exhibits poorer precision and the optimum center of rotation cannot be always acquired. Thus, adjustment by operator is necessary to determine whether the center of rotation was correct, in order that the structural information of the sample can be correctly interpreted. In this paper, the effect of center of rotation on the assessment of densitometric and structural properties of trabecular bone was firstly evaluated. Twenty female Sprague-Dawley rats of 7-month-old were randomly assigned to ovariectomized (OVX) and SHAM-operated (SHAM) groups. The left tibiae were harvested at 3 weeks postoperatively. High resolution microCT was used to identify the densitometric and microstructural properties of trabeculae in the proximal ends of tibia. After CT scanning, the best artificial center of rotation for each scan was obtained. Bone parameters analyses were performed on the centers at different places away from the best artificial center of +/-0.2, +/-0.5, +/-1.0, +/-1.5, and +/-2.0 pixels, respectively. The general linear model (GLM) repeated measures procedure was used to investigate the difference in the parameters between the two groups (OVX vs. SHAM) and the possible effects of center displacements. A significant difference between OVX and SHAM groups was found in all parameters (p < 0.05) except Tb.Th, DA, and BS/BV. TBMD, DA, BS/BV, and Conn.D were decreased while BV/TV and Tb.Th were increased with the center deflection. Variations of these parameters were acceptable when the displacements were limited within +/-1.5 pixels for tBMD, BV/TV, DA, and Conn.D, and +/-1.0 pixels for Tb.Th and BS/BV. These changes were similar in both OVX and SHAM groups. The changing curves of bone parameters vs. centers could be well fitted by quadric regression models, by which the real center could be acquired, and thus the precision of microCT analysis would be improved. There were some inevitable differences between the best artificial and real centers.

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“…2 However, application of electrocardiogram-gated 4D-CTA to assess the dynamics of aneurysm wall has shown certain limitations, the most significant of which was various visual artifacts. 3,4 We therefore developed a novel 4-dimensional visualizing technique, dynamic 4D-CTA (DFA), to more accurately evaluate the dynamics of motion in cerebral aneurysms.…”

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confidence: 99%

Novel Dynamic Four-Dimensional CT Angiography Revealing 2-Type Motions of Cerebral Arteries

Umeda

Ishida²,

Hamada³

et al. 2011

Stroke

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Background and Purpose-We developed a novel dynamic 4-dimensional CT angiography to accurately evaluate dynamics in cerebral aneurysm. Methods-Dynamic 4-dimensional CT angiography achieved high-resolution 3-dimensional imaging with temporal resolution in a beating heart using dynamic scanning data sets reconstructed with a retrospective simulated R-R interval reconstruction algorithm. Results-Movie artifacts disappeared on dynamic 4-dimensional CT angiography movies of 2 kinds of stationary phantoms (titanium clips and dry bone). In the virtual pulsating aneurysm model, pulsation on the dynamic 4-dimensional CT angiography movie resembled actual movement in terms of pulsation size. In a clinical study, dynamic 4-dimensional CT angiography showed 2-type motions: pulsation and anatomic positional changes of the cerebral artery. Key Words: aneurysm Ⅲ CT angiography Ⅲ hemodynamics H emodynamic stress is 1 factor contributing to the initiation of cerebral aneurysm and the rupture process, but simple determination of aneurysm size and location never accounts for hemodynamic forces or the ability of aneurysms to withstand them. 1 We recently succeeded in visualizing the dynamics of cerebral aneurysms with electrocardiogramgated 4-dimensional CT angiography (4D-CTA) in clinical settings. 2 However, application of electrocardiogram-gated 4D-CTA to assess the dynamics of aneurysm wall has shown certain limitations, the most significant of which was various visual artifacts. 3,4 We therefore developed a novel 4-dimensional visualizing technique, dynamic 4D-CTA (DFA), to more accurately evaluate the dynamics of motion in cerebral aneurysms. Conclusions-This MethodsDFA movies were made using dynamic scanning data sets reconstructed with a retrospective simulated R-R interval reconstruction algorithm. The accuracy of DFA was evaluated using stationary and pulsating phantoms and in 4 patients with unruptured cerebral aneurysms (available at http://stroke.ahajournals.org). Results Stationary PhantomMovie artifacts on DFA completely disappeared in a titanium clip phantom (Movie S1) and were much fewer in a dry bone phantom than electrocardiogram-gated 4D-CTA (Movie S2): the CT value was approximately 3000 and 500 Hounsfield units, respectively. Pulsating PhantomA DFA movie was constructed from 10 phases in 1 cardiac cycle and showed pulsations resembling actual movement of the virtual pulsating aneurysm model (approximately 250 to 300 Hounsfield units; Movie S3). The phase of 3-dimensional CT angiographic images was in the order of absolute time from the newest R wave ( Figure 1A). Maximum surface area and volume were observed at the same time, at approximately the 25% R-R interval ( Figure 1B). The size of pulsatile motion of the aneurysmal dome in an axial direction was approximately 0.7 mm, close to the real size of the virtual pulsating aneurysm model ( Figure 1C). Clinical DFAThe DFA movie appeared to depict real movement of arteries, not artifacts (Movie S4). Two types of movements were observed in intracranial arteries: ...

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Implementation of a cone‐beam reconstruction algorithm for the single‐circle source orbit with embedded misalignment correction using homogeneous coordinates

Cited by 58 publications

References 10 publications

High-Resolution CT for Small-Animal Imaging Research

High-Resolution CT for Small-Animal Imaging Research

The Influence of Center of Rotation on the Assessment of Trabecular Bone Densitometric and Structural Properties

Novel Dynamic Four-Dimensional CT Angiography Revealing 2-Type Motions of Cerebral Arteries

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