The dependence of image quality on the number of high and low kVp projections in dual energy CT using the prior image constrained compressed sensing (PICCS) algorithm

2010 ◽  
Author(s):  
Timothy P. Szczykutowicz ◽  
Jiang Hsieh ◽  
Guang-Hong Chen
Keyword(s):  
Image Quality ◽  
Compressed Sensing ◽  
Dual Energy ◽  
Dual Energy Ct ◽  
Low Kvp

scholarly journals Threshold-dependent iodine imaging and spectral separation in a whole-body photon-counting CT system

2021 ◽  
Author(s):  
S. Sawall ◽  
L. Klein ◽  
E. Wehrse ◽  
L. T. Rotkopf ◽  
C. Amato ◽  
...  
Keyword(s):  
Image Quality ◽  
Photon Counting ◽  
Dual Energy ◽  
Whole Body ◽  
Dual Energy Ct ◽  
Post Mortem ◽  
Tube Voltage ◽  
Spectral Separation ◽  
Dual Source ◽  
Noise Ratio

Abstract Objective To evaluate the dual-energy (DE) performance and spectral separation with respect to iodine imaging in a photon-counting CT (PCCT) and compare it to dual-source CT (DSCT) DE imaging. Methods A semi-anthropomorphic phantom extendable with fat rings equipped with iodine vials is measured in an experimental PCCT. The system comprises a PC detector with two energy bins (20 keV, T) and (T, eU) with threshold T and tube voltage U. Measurements using the PCCT are performed at all available tube voltages (80 to 140 kV) and threshold settings (50–90 keV). Further measurements are performed using a conventional energy-integrating DSCT. Spectral separation is quantified as the relative contrast media ratio R between the energy bins and low/high images. Image noise and dose-normalized contrast-to-noise ratio (CNRD) are evaluated in resulting iodine images. All results are validated in a post-mortem angiography study. Results R of the PC detector varies between 1.2 and 2.6 and increases with higher thresholds and higher tube voltage. Reference R of the EI DSCT is found as 2.20 on average overall phantoms. Maximum CNRD in iodine images is found for T = 60/65/70/70 keV for 80/100/120/140 kV. The highest CNRD of the PCCT is obtained using 140 kV and is decreasing with decreasing tube voltage. All results could be confirmed in the post-mortem angiography study. Conclusion Intrinsically acquired DE data are able to provide iodine images similar to conventional DSCT. However, PCCT thresholds should be chosen with respect to tube voltage to maximize image quality in retrospectively derived image sets. Key Points • Photon-counting CT allows for the computation of iodine images with similar quality compared to conventional dual-source dual-energy CT. • Thresholds should be chosen as a function of the tube voltage to maximize iodine contrast-to-noise ratio in derived image sets. • Image quality of retrospectively computed image sets can be maximized using optimized threshold settings.

scholarly journals Metal artefact reduction of different alloys with dual energy computed tomography (DECT)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Anand John Vellarackal ◽  
Achim Hermann Kaim
Keyword(s):  
Stainless Steel ◽  
Image Quality ◽  
Femoral Stem ◽  
Dual Energy ◽  
Dual Energy Ct ◽  
Bony Tissue ◽  
Stem Image ◽  
Metal Artefact ◽  
Artefact Reduction

AbstractTo evaluate the influence of dual-energy CT (DECT) and Virtual monochromatic spectral (VMS) imaging on: (1) the artefact size of geometrically identical orthopaedic implants consisting of three different compositions and (2) the image quality of the surrounding bone, three similar phantoms—each featuring one femoral stem composed of either titanium, chrome-cobalt or stainless steel surrounded by five calcium pellets (200 mg hydroxyapatite/calcium carbonate) to simulate bony tissue and one reference pellet located away from the femoral stem—were built. DECT with two sequential scans (80 kVp and 140 kVp; scan-to-scan technique) was performed, and VMS images were calculated between 40 and 190 keV. The artefact sizes were measured volumetrically by semiautomatic selection of regions of interest (ROIs), considering the VMS energies and the polychromatic spectres. Moreover, density and image noise within the pellets were measured. All three phantoms exhibit artefact size reduction as energy increases from 40 to 190 keV. Titanium exhibited a stronger reduction than chrome-cobalt and stainless steel. The artefacts were dependent on the diameter of the stem. Image quality increases with higher energies on VMS with a better depiction of surrounding structures. Monoenergetic energies 70 keV and 140 keV demonstrate superior image quality to those produced by spectral energies 80 kVp and 140 kVp.

Split-Bolus Portal Venous Phase Dual-Energy CT Urography: Protocol Design, Image Quality, and Dose Reduction

2015 ◽  
Vol 205 (5) ◽  
pp. W492-W501 ◽  
Author(s):  
Chiao-Yun Chen ◽  
Jui-Sheng Hsu ◽  
Twei-Shiun Jaw ◽  
Ming-Chen Paul Shih ◽  
Lo-Jeh Lee ◽  
...  
Keyword(s):  
Image Quality ◽  
Dose Reduction ◽  
Dual Energy ◽  
Protocol Design ◽  
Dual Energy Ct ◽  
Ct Urography ◽  
Portal Venous Phase ◽  
Venous Phase

scholarly journals Appropriate Patient Selection at Abdominal Dual-Energy CT Using 80 kV: Relationship between Patient Size, Image Noise, and Image Quality

Radiology ◽  
2010 ◽  
Vol 257 (3) ◽  
pp. 732-742 ◽  
Author(s):  
Luís S. Guimarães ◽  
Joel G. Fletcher ◽  
William S. Harmsen ◽  
Lifeng Yu ◽  
Hassan Siddiki ◽  
...  
Keyword(s):  
Image Quality ◽  
Patient Selection ◽  
Dual Energy ◽  
Image Noise ◽  
Dual Energy Ct ◽  
Patient Size

scholarly journals First experience with combined use of adaptive statistical iterative reconstruction and gemstone spectral imaging in spinal fusion CT images

2015 ◽  
Author(s):  
Fengdan Wang ◽  
Yan Zhang ◽  
Zhengyu Jin ◽  
Richard Zwar
Keyword(s):  
Image Quality ◽  
Iterative Reconstruction ◽  
Dual Energy ◽  
Dual Energy Ct ◽  
Metal Artifacts ◽  
Adaptive Statistical Iterative Reconstruction ◽  
Subjective Image Quality ◽  
Gemstone Spectral Imaging ◽  
Statistical Iterative Reconstruction ◽  
Combined Use

Objective. To explore whether the image noises and the metal artifacts could be further managed by the combined use of two technologies, the adaptive statistical iterative reconstruction (ASIR) and the monochromatic imaging generated by gemstone spectral imaging (GSI) dual-energy CT. Materials and Methods. Fifty-one patients with 318 spinal pedicle screws were prospectively scanned with dual energy CT by using fast kV-switching GSI between 80 and 140 kVp. The monochromatic GSI images at 110 keV were reconstructed either without ASIR or with ASIR of various levels (30%, 50%, 70% and 100%). For these five sets of images, both objective and subjective image quality assessments were performed to evaluate the image quality. Results. With objective image quality assessment, the metal artifacts (measured by an artifacts index) significantly decreased when increasing levels of ASIR was utilized (p < 0.001). Moreover, adding ASIR to GSI also decreased the image noise (p < 0.001) and improved the signal-to-noise ratio (SNR, p < 0.001). With subjective image quality analysis, the inter-reader agreements were good, with intra-class correlation coefficients (ICC) of 0.89 to 0.99. Meanwhile, the visualization of the peri-implant soft tissue was improved at higher ASIR levels (p < 0.001). Conclusion. Combined use of ASIR and GSI is shown to decrease the image noise and improve the image quality in post-spinal fusion CT scans. Optimal results were achieved with ASIR levels of over 70%.

Dual-energy CT for routine imaging of the abdomen and pelvis: radiation dose and image quality

2019 ◽  
Vol 27 (1) ◽  
pp. 45-50 ◽  
Author(s):  
Jeremy R. Wortman ◽  
Jeffrey Y. Shyu ◽  
Jeffrey Dileo ◽  
Jennifer W. Uyeda ◽  
Aaron D. Sodickson
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Dual Energy ◽  
Dual Energy Ct ◽  
Routine Imaging

Trends in radiation dose and image quality for pediatric patients with a multidetector CT and a third-generation dual-source dual-energy CT

2019 ◽  
Vol 124 (8) ◽  
pp. 745-752 ◽  
Author(s):  
Andrea Agostini ◽  
Alberto Mari ◽  
Cecilia Lanza ◽  
Nicolo’ Schicchi ◽  
Alessandra Borgheresi ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Pediatric Patients ◽  
Multidetector Ct ◽  
Dual Energy ◽  
Dual Energy Ct ◽  
Third Generation ◽  
Dual Source
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