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 Diagnosis of Pulmonary Artery Embolism: Comparison of Single-Source CT and 3rd Generation Dual-Source CT using a Dual-Energy Protocol Regarding Image Quality and Radiation Dose

2017 ◽  
Vol 189 (06) ◽  
pp. 527-536 ◽  
Author(s):  
Bernhard Petritsch ◽  
Aleksander Kosmala ◽  
Tobias Gassenmaier ◽  
Andreas Weng ◽  
Simon Veldhoen ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Dual Energy ◽  
Dual Energy Ct ◽  
Dual Source Ct ◽  
Single Source ◽  
Subjective Image Quality ◽  
Artery Embolism ◽  
Dual Source ◽  
Noise Ratio

Purpose To compare radiation dose, subjective and objective image quality of 3 rd generation dual-source CT (DSCT) and dual-energy CT (DECT) with conventional 64-slice single-source CT (SSCT) for pulmonary CTA. Materials and Methods 180 pulmonary CTA studies were performed in three patient cohorts of 60 patients each. Group 1: conventional SSCT 120 kV (ref.); group 2: single-energy DSCT 100 kV (ref.); group 3: DECT 90/Sn150 kV. CTDIvol, DLP, effective radiation dose were reported, and CT attenuation (HU) was measured on three central and peripheral levels. The signal-to-noise-ratio (SNR) and contrast-to-noise-ratio (CNR) were calculated. Two readers assessed subjective image quality according to a five-point scale. Results Mean CTDIvol and DLP were significantly lower in the dual-energy group compared to the SSCT group (p < 0.001 [CTDIvol]; p < 0.001 [DLP]) and the DSCT group (p = 0.003 [CTDIvol]; p = 0.003 [DLP]), respectively. The effective dose in the DECT group was 2.79 ± 0.95 mSv and significantly smaller than in the SSCT group (4.60 ± 1.68 mSv, p < 0.001) and the DSCT group (4.24 ± 2.69 mSv, p = 0.003). The SNR and CNR were significantly higher in the DSCT group (p < 0.001). Subjective image quality did not differ significantly among the three protocols and was rated good to excellent in 75 % (135/180) of cases with an inter-observer agreement of 80 %. Conclusion Dual-energy pulmonary CTA protocols of 3 rd generation dual-source scanners allow for significant reduction of radiation dose while providing excellent image quality and potential additional information by means of perfusion maps. Key Points: Citation Format

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

scholarly journals Optimising dual-energy CT scan parameters for virtual non-calcium imaging of the bone marrow: a phantom study

2019 ◽  
Vol 3 (1) ◽  
Author(s):  
Felix C. Müller ◽  
Henrik Børgesen ◽  
Kasper Gosvig ◽  
Anders Rodell ◽  
Christian Booz ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Dual Energy ◽  
Image Noise ◽  
Dual Energy Ct ◽  
Tube Voltage ◽  
Mean Error ◽  
Rotation Time ◽  
Spectral Separation ◽  
Reconstruction Kernel ◽  
Tin Filter

Abstract Background We investigated the influence of dose, spectral separation, pitch, rotation time, and reconstruction kernel on accuracy and image noise of virtual non-calcium images using a bone marrow phantom. Methods The phantom was developed at our institution and scanned using a third-generation dual-source dual-energy CT scanner at five different spectral separations by varying the tube-voltage combinations (70 kV/Sn150 kV, 80 kV/Sn150 kV, 90 kV/Sn150 kV, and 100 kV/Sn150 kV, all with 0.6-mm tin filter [Sn]; 80 kV/140 kV without tin filter) at six different doses (volume computed tomography dose index from 1 to 80 mGy). In separate experiments, rotation times, pitch, and reconstruction kernels were varied at a constant dose and tube voltage. Accuracy was determined by measuring the mean error between virtual non-calcium values in the fluid within and outside of the bone. Image noise was defined as the standard deviation of virtual non-calcium values. Results Spectral separation, dose, rotation time, or pitch did not significantly correlate (p > 0.083) with mean error. Increased spectral separation (rs-0.96, p < 0.001) and increased dose (rs-0.98, p < 0.001) correlated significantly with decreased image noise. Increasing sharpness of the reconstruction kernel correlated with mean error (rs 0.83, p = 0.015) and image noise (rs 1.0, p < 0.001). Conclusions Increased dose and increased spectral separation significantly lowered image noise in virtual non-calcium images but did not affect the accuracy. Virtual non-calcium reconstructions with similar accuracy and image noise could be achieved at a lower tube-voltage difference by increasing the dose.

scholarly journals Virtual monochromatic imaging in dual-source dual-energy CT: Radiation dose and image quality

2011 ◽  
Vol 38 (12) ◽  
pp. 6371-6379 ◽  
Author(s):  
Lifeng Yu ◽  
Jodie A. Christner ◽  
Shuai Leng ◽  
Jia Wang ◽  
Joel G. Fletcher ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Dual Energy ◽  
Dual Energy Ct ◽  
Virtual Monochromatic Imaging ◽  
Monochromatic Imaging ◽  
Ct Radiation ◽  
Dual Source

scholarly journals Characterization of Urinary Stone Composition by Use of Third-Generation Dual-Source Dual-Energy CT With Increased Spectral Separation

2015 ◽  
Vol 205 (6) ◽  
pp. 1203-1207 ◽  
Author(s):  
Xinhui Duan ◽  
Zhoubo Li ◽  
Lifeng Yu ◽  
Shuai Leng ◽  
Ahmed F. Halaweish ◽  
...  
Keyword(s):  
Urinary Stone ◽  
Dual Energy ◽  
Dual Energy Ct ◽  
Third Generation ◽  
Stone Composition ◽  
Spectral Separation ◽  
Dual Source

scholarly journals Salvage of Suboptimal Enhancement of Pulmonary Artery in Pulmonary CT Angiography Studies: Rapid kVp Switch Dual Energy CT Experience

2020 ◽  
Vol 17 (2) ◽  
Author(s):  
Selen Bayraktaroglu ◽  
Akın Cinkooglu ◽  
Naim Ceylan ◽  
Recep Savas
Keyword(s):  
Pulmonary Embolism ◽  
Image Quality ◽  
Pulmonary Artery ◽  
Imaging Modality ◽  
Main Pulmonary Artery ◽  
Pulmonary Arteries ◽  
Dual Energy ◽  
Dual Energy Ct ◽  
Average Increase ◽  
Noise Ratio

Background: Multidetector computed tomography (MDCT) angiography is considered as the gold standard imaging modality in the evaluation of acute pulmonary embolism. Optimum vascular enhancement is critical for MDCT studies. The suboptimal opacification in pulmonary artery could be salvaged using low-energy virtual monoenergetic images (VMI) at rapid kVp switch dual energy CT. Objectives: To explore the potential improvement in pulmonary artery opacification and to assess the change in image quality parameters in VMI using fast switch kVp dual energy CT. Patients and Methods: The CT images of 877 patients who were referred with a preliminary diagnosis of pulmonary embolism were reviewed. Sixty patients with suboptimal enhancement (< 200 Hounsfeld Unit [HU]) were involved. Standard images (140 kVp) and VMI from 40 to 120 keV were generated. Attenuation, noise, signal to noise ratio (SNR) and contrast to noise ratio (CNR) were measured in the pulmonary artery. Using VMIs, the best image was determined as the image with the main pulmonary artery opacification greater than 200 HU and image quality ≥ 3. Fifty six studies that met these criteria were considered as salvaged. At this best energy level, quantitative parameters were compared with standard images. Results: The mean attenuation of pulmonary arteries was 169.80 HU in standard images in patients with suboptimal enhancement. The attenuations of VMIs at 40, 45, 50, 55, 60, 65, and 70 keV were significantly higher than standard images (P < 0.001). Similar findings were observed with SNR and CNR. In the salvaged patients, the average increase in mean pulmonary artery attenuation was 62% (from 172.61 ± 23.4 to 280.55 ± 40.7), the average increase in SNR was 38% (from 12.1 ± 5.3 to 16.7 ± 7.1) and the average increase in CNR was 48% (9.2 ± 4.3 to 13.7 ± 6) (P < 0.001). Conclusions: Low keV VMI reconstructions significantly increase pulmonary artery attenuation, CNR and SNR compared to standard image reconstructions. Suboptimal CT studies could be salvaged using low keV VMIs.

Single- and dual-energy CT pulmonary angiography using second- and third-generation dual-source CT systems: comparison of radiation dose and image quality

2019 ◽  
Vol 29 (9) ◽  
pp. 4603-4612 ◽  
Author(s):  
Lukas Lenga ◽  
Franziska Trapp ◽  
Moritz H. Albrecht ◽  
Julian L. Wichmann ◽  
Addison A. Johnson ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Pulmonary Angiography ◽  
Dual Energy ◽  
Dual Energy Ct ◽  
Third Generation ◽  
Dual Source Ct ◽  
Ct Pulmonary Angiography ◽  
Dual Source

scholarly journals Dual-Source Dual-Energy CT With Additional Tin Filtration: Dose and Image Quality Evaluation in Phantoms and In Vivo

2010 ◽  
Vol 195 (5) ◽  
pp. 1164-1174 ◽  
Author(s):  
Andrew N. Primak ◽  
Juan Carlos Ramirez Giraldo ◽  
Christian D. Eusemann ◽  
Bernhard Schmidt ◽  
Birgit Kantor ◽  
...  
Keyword(s):  
Image Quality ◽  
Quality Evaluation ◽  
Dual Energy ◽  
Dual Energy Ct ◽  
Image Quality Evaluation ◽  
Dual Source ◽  
Tin Filtration

Automatic Bone Removal Technique in Whole-Body Dual-Energy CT Angiography: Performance and Image Quality

2012 ◽  
Vol 199 (5) ◽  
pp. W646-W650 ◽  
Author(s):  
Boris Schulz ◽  
Katharina Kuehling ◽  
Wolfgang Kromen ◽  
Petra Siebenhandl ◽  
Matthias Josef Kerl ◽  
...  
Keyword(s):  
Image Quality ◽  
Ct Angiography ◽  
Dual Energy ◽  
Whole Body ◽  
Dual Energy Ct ◽  
Bone Removal ◽  
Removal Technique
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