scholarly journals Influence of beam hardening in dual-energy CT imaging: phantom study for iodine mapping, virtual monoenergetic imaging, and virtual non-contrast imaging

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Risa Kanatani ◽  
Takashi Shirasaka ◽  
Tsukasa Kojima ◽  
Toyoyuki Kato ◽  
Masateru Kawakubo
Keyword(s):  
Dual Energy ◽  
Dual Energy Ct ◽  
Contrast Imaging ◽  
Beam Hardening ◽  
X Ray ◽  
Rubber Layer ◽  
Density Values ◽  
Monoenergetic Imaging ◽  
Iodine Map ◽  
Ct Density

AbstractIn this study, we investigated the influence of beam hardening on the dual-energy computed tomography (DECT) values of iodine maps, virtual monoenergetic (VME) images, and virtual non-contrast (VNC) images. 320-row DECT imaging was performed by changing the x-ray tube energy for the first and second rotations. DECT values of 5 mg/mL iodine of the multi-energy CT phantom were compared with and without a 2-mm-thick attenuation rubber layer (~700 HU) wound around the phantom. It was found that the CT density values UH, with/without the rubber layer had statistical differences in the iodine map (184 ± 0.7 versus 186 ± 1.8), VME images (125 ± 0.3 versus 110 ± 0.4), and VNC images (−58 ± 0.7 versus −76 ± 1.7) (p < 0.010 for all). This suggests that iodine mapping may be underestimated by DECT and overestimated by VME imaging because of x-ray beam hardening. The use of VNC images instead of plain CT images requires further investigation because of underestimation.

A Spectrum-Adaptive Decomposition Method for Effective Atomic Number Estimation Using Dual Energy CT

2020 ◽  
Vol 2020 (14) ◽  
pp. 293-1-293-7
Author(s):  
Ankit Manerikar ◽  
Fangda Li ◽  
Avinash C. Kak
Keyword(s):  
Atomic Number ◽  
Decomposition Method ◽  
Traditional Approach ◽  
Effective Atomic Number ◽  
Dual Energy ◽  
Performance Comparison ◽  
Estimation Methods ◽  
Dual Energy Ct ◽  
Projection Data ◽  
X Ray

Dual Energy Computed Tomography (DECT) is expected to become a significant tool for voxel-based detection of hazardous materials in airport baggage screening. The traditional approach to DECT imaging involves collecting the projection data using two different X-ray spectra and then decomposing the data thus collected into line integrals of two independent characterizations of the material properties. Typically, one of these characterizations involves the effective atomic number (Zeff) of the materials. However, with the X-ray spectral energies typically used for DECT imaging, the current best-practice approaches for dualenergy decomposition yield Zeff values whose accuracy range is limited to only a subset of the periodic-table elements, more specifically to (Z < 30). Although this estimation can be improved by using a system-independent ρe — Ze (SIRZ) space, the SIRZ transformation does not efficiently model the polychromatic nature of the X-ray spectra typically used in physical CT scanners. In this paper, we present a new decomposition method, AdaSIRZ, that corrects this shortcoming by adapting the SIRZ decomposition to the entire spectrum of an X-ray source. The method reformulates the X-ray attenuation equations as direct functions of (ρe, Ze) and solves for the coefficients using bounded nonlinear least-squares optimization. Performance comparison of AdaSIRZ with other Zeff estimation methods on different sets of real DECT images shows that AdaSIRZ provides a higher output accuracy for Zeff image reconstructions for a wider range of object materials.

scholarly journals Dynamic single-slice CT estimates whole-lung dual-energy CT variables in pigs with and without experimental lung injury

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
John N. Cronin ◽  
João Batista Borges ◽  
Douglas C. Crockett ◽  
Andrew D. Farmery ◽  
Göran Hedenstierna ◽  
...  
Keyword(s):  
Lung Injury ◽  
Dual Energy ◽  
Dual Energy Ct ◽  
Lung Density ◽  
Density Distributions ◽  
Single Slice ◽  
Injury Model ◽  
Lung Injury Model ◽  
Ct Density ◽  
Surfactant Depletion

Abstract Background Dynamic single-slice CT (dCT) is increasingly used to examine the intra-tidal, physiological variation in aeration and lung density in experimental lung injury. The ability of dCT to predict whole-lung values is unclear, especially for dual-energy CT (DECT) variables. Additionally, the effect of inspiration-related lung movement on CT variables has not yet been quantified. Methods Eight domestic pigs were studied under general anaesthesia, including four following saline-lavage surfactant depletion (lung injury model). DECT, dCT and whole-lung images were collected at 12 ventilatory settings. Whole-lung single energy scans images were collected during expiratory and inspiratory apnoeas at positive end-expiratory pressures from 0 to 20 cmH2O. Means and distributions of CT variables were calculated for both dCT and whole-lung images. The cranio-caudal displacement of the anatomical slice was measured from whole-lung images. Results Mean CT density and volume fractions of soft tissue, gas, iodinated blood, atelectasis, poor aeration, normal aeration and overdistension correlated between dCT and the whole lung (r2 0.75–0.94) with agreement between CT density distributions (r 0.89–0.97). Inspiration increased the matching between dCT and whole-lung values and was associated with a movement of 32% (SD 15%) of the imaged slice out of the scanner field-of-view. This effect introduced an artefactual increase in dCT mean CT density during inspiration, opposite to that caused by the underlying physiology. Conclusions Overall, dCT closely approximates whole-lung aeration and density. This approximation is improved by inspiration where a decrease in CT density and atelectasis can be interpreted as physiological rather than artefactual.

Dual Energy X-Ray Absorptiometry-Based Assessment of Male Patients Using Standardized Bone Density Values and a National Reference Database

2007 ◽  
Vol 10 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Stefan Goemaere ◽  
Dirk Vanderschueren ◽  
Jean-Marc Kaufman ◽  
Jean-Yves Reginster ◽  
Yves Boutsen ◽  
...  
Keyword(s):  
Bone Density ◽  
Dual Energy ◽  
Reference Database ◽  
X Ray ◽  
National Reference ◽  
Density Values ◽  
Male Patients

Theory and method of dual-energy x-ray grating phase-contrast imaging

2019 ◽  
Vol 28 (10) ◽  
pp. 108702
Author(s):  
Feng Rong ◽  
Yan Gao ◽  
Cui-Juan Guo ◽  
Wei Xu ◽  
Wei Xu
Keyword(s):  
Phase Contrast ◽  
Dual Energy ◽  
Phase Contrast Imaging ◽  
Contrast Imaging ◽  
X Ray

scholarly journals Dual energy CT findings in gout with rapid kilovoltage-switching source with gemstone scintillator detector

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Elin Svensson ◽  
Ylva Aurell ◽  
Lennart T. H. Jacobsson ◽  
Anton Landgren ◽  
Valgerdur Sigurdardottir ◽  
...  
Keyword(s):  
Synovial Fluid ◽  
Dual Energy ◽  
University Hospital ◽  
Dual Energy Ct ◽  
Kappa Statistics ◽  
Monosodium Urate ◽  
Beam Hardening ◽  
Monosodium Urate Crystals ◽  
Scintillator Detector ◽  
Urate Crystals

Abstract Background A definite diagnosis of gout requires demonstration of monosodium urate crystals in synovial fluid or in tophi, which in clinical practice today seldom is done. Dual energy CT (DECT) has repeatedly been shown to be able to detect monosodium urate crystals in tissues, hence being an alternative method to synovial fluid microscopy. The vast majority of these studies were performed with CT scanners with two X-ray tubes. In the present study we aim to investigate if and at what locations DECT with rapid kilovoltage-switching source with gemstone scintillator detector (GSI) can identify MSU crystals in patients with clinically diagnosed gout. We also performed a reliability study between two independent readings. Methods Patients with new or established gout who had been examined with DECT GSI scanning of the feet at Sahlgrenska University Hospital, Mölndal between 2015 and 2018 were identified. Their medical records were sought for gout disease characteristics using a structured protocol. Urate deposits in MTP1, MTP 2–5, ankle/midfoot joints and tendons were scored semiquantatively in both feet and presence of artifacts in nail and skin as well as beam hardening and noise were recorded. Two radiologists performed two combined readings and scoring of the images, thus consensus was reached over the scoring at each occasion (Espeland et al., BMC Med Imaging. 2013;13:4). The two readings were compared with kappa statistics. Results DECT GSI could identify urate deposits in the feet of all 55 participants with gout. Deposits were identified in the MTP-joints of all subjects but were also present in ankle/midfoot joints and tendons in 96 and 75% respectively. Deposition of urate was predicted by longer disease duration (Spearman’s Rho 0.64, p < .0001) and presence of tophi (p = 0.0005). Artifacts were common and mostly found in the nails (73%), a minority displayed skin artifacts (31%) while beam hardening and noise was rare. The agreement between the two readings was good (Κ = 0.66, 95% CI = 0.61–0.71). Conclusion The validity of DECT GSI in gout is supported by the identification of urate in all patients with clinical gout and the good correlations with clinical characteristics. The occurrence of artifacts was relatively low with expected locations.

Performance of today's dual energy CT and future multi energy CT in virtual non-contrast imaging and in iodine quantification: A simulation study

2015 ◽  
Vol 42 (7) ◽  
pp. 4349-4366 ◽  
Author(s):  
Sebastian Faby ◽  
Stefan Kuchenbecker ◽  
Stefan Sawall ◽  
David Simons ◽  
Heinz-Peter Schlemmer ◽  
...  
Keyword(s):  
Simulation Study ◽  
Dual Energy ◽  
Dual Energy Ct ◽  
Contrast Imaging ◽  
Iodine Quantification

Optimization of keV-settings in abdominal and lower extremity dual-source dual-energy CT angiography determined with virtual monoenergetic imaging

2013 ◽  
Vol 82 (10) ◽  
pp. e574-e581 ◽  
Author(s):  
Sonja Sudarski ◽  
Paul Apfaltrer ◽  
John W. Nance ◽  
David Schneider ◽  
Mathias Meyer ◽  
...  
Keyword(s):  
Lower Extremity ◽  
Ct Angiography ◽  
Dual Energy ◽  
Dual Energy Ct ◽  
Virtual Monoenergetic Imaging ◽  
Dual Source ◽  
Monoenergetic Imaging
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