scholarly journals Feasibility of improving vascular imaging in the presence of metallic stents using spectral photon counting CT and K-edge imaging

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Monica Sigovan ◽  
Salim Si-Mohamed ◽  
Daniel Bar-Ness ◽  
Julia Mitchell ◽  
Jean-Baptiste Langlois ◽  
...  
Keyword(s):  
Photon Counting ◽  
Dual Energy ◽  
Apparent Size ◽  
Metallic Stents ◽  
Dual Energy Ct ◽  
Vascular Calcifications ◽  
Vascular Lumen ◽  
Ct System ◽  
Stent Lumen

AbstractCorrect visualization of the vascular lumen is impaired in standard computed tomography (CT) because of blooming artifacts, increase of apparent size, induced by metallic stents and vascular calcifications. Recently, due to the introduction of photon-counting detectors in the X-ray imaging field, a new prototype spectral photon-counting CT (SPCCT) based on a modified clinical CT system has been tested in a feasibility study for improving vascular lumen delineation and visualization of coronary stent architecture. Coronary stents of different metal composition were deployed inside plastic tubes containing hydroxyapatite spheres to simulate vascular calcifications and in the abdominal aorta of one New Zealand White (NZW) rabbit. Imaging was performed with an SPCCT prototype, a dual-energy CT system, and a conventional 64-channel CT system (B64). We found the apparent widths of the stents significantly smaller on SPCCT than on the other two systems in vitro (p < 0.01), thus closer to the true size. Consequently, the intra-stent lumen was significantly larger on SPCCT (p < 0.01). In conclusion, owing to the increased spatial resolution of SPCCT, improved lumen visualization and delineation of stent metallic mesh is possible compared to dual-energy and conventional CT.

Characterization of thrombus composition with multimodality CT-based imaging: an in-vitro study

2020 ◽  
pp. neurintsurg-2020-016799
Author(s):  
Yong-Hong Ding ◽  
Mehdi Abbasi ◽  
Gregory Michalak ◽  
Shuai Leng ◽  
Daying Dai ◽  
...  
Keyword(s):  
Imaging Modality ◽  
Photon Counting ◽  
In Vitro Study ◽  
Ct Scanning ◽  
Dual Energy ◽  
Vitro Study ◽  
Dual Energy Ct ◽  
Vessel Occlusion ◽  
Photon Counting Detector

BackgroundCT is the most commonly used imaging modality for acute ischemic stroke evaluation. There is growing interest to use pre-operative imaging to characterize clot composition in stroke. We performed an in-vitro study examining the ability of various CT techniques in differentiation between different clot types.MethodsFive clot types with varying fibrin and red blood cells (RBCs) densities (5% RBC and 95% fibrin; 25% RBC and 75% fibrin; 50% RBC and 50% fibrin; 75% RBC and 25% fibrin; 95% RBC and 5% fibrin) were prepared and scanned using various CT scanning protocols (single-energy, dual-energy, photon-counting detector CT, mixed images, and virtual monoenergetic images). Martius Scarlett Blue trichrome staining was performed to confirm the composition of each clot. Mean CT values of each type of clot under different scanning protocol were calculated and compared.ResultsMean CT values of the CT numbers in the five clot specimens for 5%, 25%, and 50% RBC clot were similar across modalities, and increased significantly for 75% and 95% RBC clots (P<0.0001). Mean CT values are highest in the Mono +50 keV images in each type of clot, and they were also significantly higher than all other imaging protocols (P<0.001). Dual-energy CT with Mono +50 keV images showed the greatest difference between attenuation in each type of clot.ConclusionMono +50 keV dual-energy CT scan may be helpful for differentiating between RBC-rich and fibrin-rich thrombi seen in large-vessel occlusion patients.

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.

Dual-energy CT for the characterization of urinary calculi: In vitro and in vivo evaluation of a low-dose scanning protocol

2009 ◽  
Vol 19 (6) ◽  
pp. 1553-1559 ◽  
Author(s):  
C. Thomas ◽  
O. Patschan ◽  
D. Ketelsen ◽  
I. Tsiflikas ◽  
A. Reimann ◽  
...  
Keyword(s):  
Low Dose ◽  
Urinary Calculi ◽  
Dual Energy ◽  
Dual Energy Ct ◽  
In Vivo Evaluation ◽  
Scanning Protocol

DUAL ENERGY CT (DECT) CHARACTERISATION OF URINARY CALCULI: INITIAL IN VITRO AND CLINICAL EXPERIENCE

2008 ◽  
Vol 7 (3) ◽  
pp. 152
Author(s):  
M.J. Bader ◽  
N. Haseke ◽  
T.R.C. Johnson ◽  
A. Graser ◽  
M. Staehler ◽  
...  
Keyword(s):  
Clinical Experience ◽  
Urinary Calculi ◽  
Dual Energy ◽  
Dual Energy Ct

scholarly journals Utility of single-energy and dual-energy computed tomography in clot characterization: An in-vitro study

2017 ◽  
Vol 23 (3) ◽  
pp. 279-284 ◽  
Author(s):  
Waleed Brinjikji ◽  
Gregory Michalak ◽  
Ramanathan Kadirvel ◽  
Daying Dai ◽  
Michael Gilvarry ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Receiver Operating Characteristic ◽  
Operating Characteristic ◽  
Area Under The Curve ◽  
In Vitro Study ◽  
Dual Energy ◽  
Dual Energy Ct

Background and purpose Because computed tomography (CT) is the most commonly used imaging modality for the evaluation of acute ischemic stroke patients, developing CT-based techniques for improving clot characterization could prove useful. The purpose of this in-vitro study was to determine which single-energy or dual-energy CT techniques provided optimum discrimination between red blood cell (RBC) and fibrin-rich clots. Materials and methods Seven clot types with varying fibrin and RBC densities were made (90% RBC, 99% RBC, 63% RBC, 36% RBC, 18% RBC and 0% RBC with high and low fibrin density) and their composition was verified histologically. Ten of each clot type were created and scanned with a second generation dual source scanner using three single (80 kV, 100 kV, 120 kV) and two dual-energy protocols (80/Sn 140 kV and 100/Sn 140 kV). A region of interest (ROI) was placed over each clot and mean attenuation was measured. Receiver operating characteristic curves were calculated at each energy level to determine the accuracy at differentiating RBC-rich clots from fibrin-rich clots. Results Clot attenuation increased with RBC content at all energy levels. Single-energy at 80 kV and 120 kV and dual-energy 80/Sn 140 kV protocols allowed for distinguishing between all clot types, with the exception of 36% RBC and 18% RBC. On receiver operating characteristic curve analysis, the 80/Sn 140 kV dual-energy protocol had the highest area under the curve for distinguishing between fibrin-rich and RBC-rich clots (area under the curve 0.99). Conclusions Dual-energy CT with 80/Sn 140 kV had the highest accuracy for differentiating RBC-rich and fibrin-rich in-vitro thrombi. Further studies are needed to study the utility of non-contrast dual-energy CT in thrombus characterization in acute ischemic stroke.

scholarly journals A low-cost dual energy CT system with sparse data

2014 ◽  
Vol 19 (2) ◽  
pp. 184-194 ◽  
Author(s):  
Yuanyuan Liu ◽  
Jianping Cheng ◽  
Li Zhang ◽  
Yuxiang Xing ◽  
Zhiqiang Chen ◽  
...  
Keyword(s):  
Low Cost ◽  
Sparse Data ◽  
Dual Energy ◽  
Dual Energy Ct ◽  
Ct System

Visualization of joint and bone using dual-energy CT arthrography with contrast subtraction: in vitro feasibility study using porcine joints

2014 ◽  
Vol 43 (5) ◽  
pp. 673-678 ◽  
Author(s):  
Jee Won Chai ◽  
Jung-Ah Choi ◽  
Ja-Young Choi ◽  
Sujin Kim ◽  
Sung Hwan Hong ◽  
...  
Keyword(s):  
Feasibility Study ◽  
Dual Energy ◽  
Dual Energy Ct ◽  
Ct Arthrography

scholarly journals Quantitative dual-energy CT material decomposition of holmium microspheres: local concentration determination evaluated in phantoms and a rabbit tumor model

2020 ◽  
Vol 31 (1) ◽  
pp. 139-148
Author(s):  
Ralf Gutjahr ◽  
Robbert C. Bakker ◽  
Feiko Tiessens ◽  
Sebastiaan A. van Nimwegen ◽  
Bernhard Schmidt ◽  
...  
Keyword(s):  
Tumor Model ◽  
Dual Energy ◽  
Dual Energy Ct ◽  
Local Concentration ◽  
Third Generation ◽  
Ct Scanner ◽  
Material Decomposition ◽  
Tube Voltage ◽  
Calibration Phantom ◽  
Ct System

Abstract Objectives The purpose of this study was to assess the feasibility of dual-energy CT-based material decomposition using dual-X-ray spectra information to determine local concentrations of holmium microspheres in phantoms and in an animal model. Materials and methods A spectral calibration phantom with a solution containing 10 mg/mL holmium and various tube settings was scanned using a third-generation dual-energy CT scanner to depict an energy-dependent and material-dependent enhancement vectors. A serial dilution of holmium (microspheres) was quantified by spectral material decomposition and compared with known holmium concentrations. Subsequently, the feasibility of the spectral material decomposition was demonstrated in situ in three euthanized rabbits with injected (radioactive) holmium microspheres. Results The measured CT values of the holmium solutions scale linearly to all measured concentrations and tube settings (R2 = 1.00). Material decomposition based on CT acquisitions using the tube voltage combinations of 80/150 Sn kV or 100/150 Sn kV allow the most accurate quantifications for concentrations down to 0.125 mg/mL holmium. Conclusion Dual-energy CT facilitates image-based material decomposition to detect and quantify holmium microspheres in phantoms and rabbits. Key Points • Quantification of holmium concentrations based on dual-energy CT is obtained with good accuracy. • The optimal tube-voltage pairs for quantifying holmium were 80/150 Sn kV and 100/150 Sn kV using a third-generation dual-source CT system. • Quantification of accumulated holmium facilitates the assessment of local dosimetry for radiation therapies.

Iterative dynamic dual-energy CT algorithm in reducing statistical noise in multi-energy CT imaging

2021 ◽  
Author(s):  
Yidi Yao ◽  
Liang Li ◽  
Zhiqiang Chen
Keyword(s):  
Noise Level ◽  
Photon Counting ◽  
Reconstruction Algorithm ◽  
Dual Energy ◽  
Ct Imaging ◽  
Dual Energy Ct ◽  
Spectral Ct ◽  
Photon Counting Detectors ◽  
Ct Data ◽  
Statistical Noise

Abstract Multi-energy spectral CT has a broader range of applications with the recent development of photon-counting detectors. However, the photons counted in each energy bin decrease when the number of energy bins increases, which causes a higher statistical noise level of the CT image. In this work, we propose a novel iterative dynamic dual-energy CT algorithm to reduce the statistical noise. In the proposed algorithm, the multi-energy projections are estimated from the dynamic dual-energy CT data during the iterative process. The proposed algorithm is verified on sufficient numerical simulations and a laboratory two-energy-threshold PCD system. By applying the same reconstruction algorithm, the dynamic dual-energy CT's final reconstruction results have a much lower statistical noise level than the conventional multi-energy CT. Moreover, based on the analysis of the simulation results, we explain why the dynamic dual-energy CT has a lower statistical noise level than the conventional multi-energy CT. The reason is that: the statistical noise level of multi-energy projection estimated with the proposed algorithm is much lower than that of the conventional multi-energy CT, which leads to less statistical noise of the dynamic dual-energy CT imaging.

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