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

Combined use of iterative reconstruction and monochromatic imaging in spinal fusion CT images

2016 ◽  
Vol 58 (1) ◽  
pp. 62-69 ◽  
Author(s):  
Fengdan Wang ◽  
Yan Zhang ◽  
Huadan Xue ◽  
Wei Han ◽  
Xianda Yang ◽  
...  
Keyword(s):  
Image Quality ◽  
Spinal Fusion ◽  
Iterative Reconstruction ◽  
Dual Energy ◽  
Image Noise ◽  
Dual Energy Ct ◽  
Spinal Diseases ◽  
Metal Artifacts ◽  
Monochromatic Imaging ◽  
Combined Use

Background Spinal fusion surgery is an important procedure for treating spinal diseases and computed tomography (CT) is a critical tool for postoperative evaluation. However, CT image quality is considerably impaired by metal artifacts and image noise. Purpose To explore whether metal artifacts and image noise can be reduced by combining two technologies, adaptive statistical iterative reconstruction (ASIR) and monochromatic imaging generated by gemstone spectral imaging (GSI) dual-energy CT. Material and Methods A total of 51 patients with 318 spinal pedicle screws were prospectively scanned by dual-energy CT using fast kV-switching GSI between 80 and 140 kVp. Monochromatic GSI images at 110 keV were reconstructed either without or with various levels of ASIR (30%, 50%, 70%, and 100%). The quality of five sets of images was objectively and subjectively assessed. Results With objective image quality assessment, metal artifacts decreased when increasing levels of ASIR were applied ( P < 0.001). Moreover, adding ASIR to GSI also decreased image noise ( P < 0.001) and improved the signal-to-noise ratio ( P < 0.001). The subjective image quality analysis showed good inter-reader concordance, with intra-class correlation coefficients between 0.89 and 0.99. The visualization of peri-implant soft tissue was improved at higher ASIR levels ( P < 0.001). Conclusion Combined use of ASIR and GSI decreased image noise and improved image quality in post-spinal fusion CT scans. Optimal results were achieved with ASIR levels ≥70%.

scholarly journals Reliability of virtual non-contrast computed tomography angiography: comparing it with the real deal

2018 ◽  
Vol 7 (7-8) ◽  
pp. 205846011879011 ◽  
Author(s):  
Leena Lehti ◽  
Marcus Söderberg ◽  
Peter Höglund ◽  
Ulf Nyman ◽  
Anders Gottsäter ◽  
...  
Keyword(s):  
Image Quality ◽  
Subjective Evaluation ◽  
Computed Tomographic Angiography ◽  
Dual Energy ◽  
Image Noise ◽  
Arterial Phase ◽  
Dual Energy Ct ◽  
Computed Tomographic ◽  
Contrast Enhanced ◽  
Tomographic Angiography

Background Computed tomographic angiography (CTA) may require a non-contrast enhanced dataset for the diagnostic workup. By using dual-energy acquisition, it is possible to obtain a virtual non-contrast-enhanced (VNC) dataset, thereby possibly eliminating the non-contrast acquisition and reducing the radiation dose. Purpose To compare image quality of VNC images reconstructed from arterial phase dual-energy CTA to true non-contrast (TNC) images, and to assess whether VNC images were of sufficient quality to replace TNC images. Material and methods Thirty consecutive patients with suspected abdominal aortic aneurysm, aortic dissection, or subacute control after EVAR/TEVAR were examined with dual-energy CT (DECT). The examination protocol included a single-energy TNC, DECT arterial phase (80 kV/Sn140 kV), and single-energy in venous phase of the aorta. A VNC dataset was obtained from the DE acquisition from arterial phase scans. Mean attenuation and image noise were measured within regions of interest at three levels in the aorta in TNC and VNC images. Comparison of the TNC and VNC images for artefacts was made side-by-side. Subjective evaluation included overall image quality on a 4-grade scale, and quantitative analysis of algorithm-induced artefacts by two experienced readers. Results For all cases, the aortic attenuation was significantly higher at VNC than at TNC. Image noise measured quantitatively was also significantly higher at VNC than at TNC. Subjective image quality was lower for VNC (mean = 3.1 for VNC, 3.7 = for TNC) but there were no cases rated non-diagnostic. Conclusion VNC images based on arterial phase CTA have significantly higher mean attenuation and higher noise levels compared to TNC.

Third generation dual-energy CT with 80/150 Sn kV for head and neck tumor imaging

2018 ◽  
Vol 60 (5) ◽  
pp. 586-592 ◽  
Author(s):  
Saravanabavaan Suntharalingam ◽  
Elena Stenzel ◽  
Axel Wetter ◽  
Nika Guberina ◽  
Lale Umutlu ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Head And Neck ◽  
Tumor Imaging ◽  
Neck Region ◽  
Dual Energy ◽  
Image Noise ◽  
Dual Energy Ct ◽  
Third Generation ◽  
Floor Of Mouth

Background Dual-energy CT (DECT) provides additional image datasets which enable improved tumor delineation or reduction of beam hardening artifacts in patients with head and neck squamous cell carcinoma (SCC). Purpose To assess radiation dose and image quality of third-generation DECT of the head and neck in comparison to single-energy CT (SECT). Material and Methods Thirty patients with SCC who underwent both SECT (reference tube voltage 120 kVp) and DECT (80/150 Sn kVp) of the head and neck region for staging were retrospectively selected. Attenuation measurements of the sternomastoid muscle, internal jugular vein, submandibular gland and tongue were compared. Image noise was assessed at five anatomic levels. Subjective image quality was evaluated by two radiologists in consensus. Results CTDIvol was 55% lower with DECT (4.2 vs. 9.3 mGy; P = 0.002). Median image noise was equal or lower in DECT at all levels (nasopharynx: 3.9 vs. 5.8, P < 0.0001; floor of mouth: 3.6 vs. 4.5, P = 0.0002; arytenoids: 3.6 vs. 3.1, P = 0.096; lower thyroid: 4.4 vs. 5.7, P = 0.002; arch of aorta: 5.6 vs. 6.5, P = 0.001). Attenuation was significantly lower in DECT ( P < 0.05). Subjective image analysis revealed that DECT is equal or superior to SECT with regard to overall image quality (nasopharynx: 5 vs. 5, P = 1; floor of mouth: 5 vs. 5, P = 0.0041; arytenoids: 5 vs. 5, P = 0.6; lower thyroid: 5 vs. 3, P < 0.0001; arch of aorta: 5 vs. 4, P < 0.0001). Conclusion Head and neck imaging with third-generation DECT can reduce radiation dose by half compared to SECT, while maintaining excellent image quality.

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 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
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