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Graf M, Gassert FG, Marka AW, Gassert FT, Ziegelmayer S, Makowski M, Kallmayer M, Nadjiri J. Spectral computed tomography angiography using a gadolinium-based contrast agent for imaging of pathologies of the aorta. Int J Cardiovasc Imaging 2024; 40:1059-1066. [PMID: 38421538 PMCID: PMC11147857 DOI: 10.1007/s10554-024-03074-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Accepted: 02/22/2024] [Indexed: 03/02/2024]
Abstract
OBJECTIVES Especially patients with aortic aneurysms and multiple computed tomography angiographies (CTA) might show medical conditions which oppose the use of iodine-based contrast agents. CTA using monoenergetic reconstructions from dual layer CT and gadolinium (Gd-)based contrast agents might be a feasible alternative in these patients. Therefore, the purpose of this study was to evaluate the feasibility of clinical spectral CTA with a Gd-based contrast agent in patients with aortic aneurysms. METHODS Twenty-one consecutive scans in 15 patients with and without endovascular aneurysm repair showing contraindications for iodine-based contrast agents were examined using clinical routine doses (0.2 mmol/kg) of Gd-based contrast agent with spectral CT. Monoenergetic reconstructions of the spectral data set were computed. RESULTS There was a significant increase in the intravascular attenuation of the aorta between pre- and post-contrast images for the MonoE40 images in the thoracic and the abdominal aorta (p < 0.001 for both). Additionally, the ratio between pre- and post-contrast images was significantly higher in the MonoE40 images as compared to the conventional images with a factor of 6.5 ± 4.5 vs. 2.4 ± 0.5 in the thoracic aorta (p = 0.003) and 4.1 ± 1.8 vs. 1.9 ± 0.5 in the abdominal aorta (p < 0.001). CONCLUSIONS To conclude, our study showed that Gd-CTA is a valid and reliable alternative for diagnostic imaging of the aorta for clinical applications. Monoenergetic reconstructions of computed tomography angiographies using gadolinium based contrast agents may be a useful alternative in patients with aortic aneurysms and contraindications for iodine based contrast agents.
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Affiliation(s)
- Markus Graf
- Department of Diagnostic and Interventional Radiology, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, Ismaninger Straße 22, 81675, Munich, Germany.
| | - Felix G Gassert
- Department of Diagnostic and Interventional Radiology, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, Ismaninger Straße 22, 81675, Munich, Germany
| | - Alexander W Marka
- Department of Diagnostic and Interventional Radiology, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, Ismaninger Straße 22, 81675, Munich, Germany
| | - Florian T Gassert
- Department of Diagnostic and Interventional Radiology, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, Ismaninger Straße 22, 81675, Munich, Germany
| | - Sebastian Ziegelmayer
- Department of Diagnostic and Interventional Radiology, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, Ismaninger Straße 22, 81675, Munich, Germany
| | - Marcus Makowski
- Department of Diagnostic and Interventional Radiology, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, Ismaninger Straße 22, 81675, Munich, Germany
| | - Michael Kallmayer
- Department of Vascular and Endovascular Surgery, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, Ismaninger Straße 22, 81675, Munich, Germany
| | - Jonathan Nadjiri
- Department of Interventional Radiology, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, Ismaninger Straße 22, 81675, Munich, Germany
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Bousse A, Kandarpa VSS, Rit S, Perelli A, Li M, Wang G, Zhou J, Wang G. Systematic Review on Learning-based Spectral CT. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2024; 8:113-137. [PMID: 38476981 PMCID: PMC10927029 DOI: 10.1109/trpms.2023.3314131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2024]
Abstract
Spectral computed tomography (CT) has recently emerged as an advanced version of medical CT and significantly improves conventional (single-energy) CT. Spectral CT has two main forms: dual-energy computed tomography (DECT) and photon-counting computed tomography (PCCT), which offer image improvement, material decomposition, and feature quantification relative to conventional CT. However, the inherent challenges of spectral CT, evidenced by data and image artifacts, remain a bottleneck for clinical applications. To address these problems, machine learning techniques have been widely applied to spectral CT. In this review, we present the state-of-the-art data-driven techniques for spectral CT.
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Affiliation(s)
- Alexandre Bousse
- LaTIM, Inserm UMR 1101, Université de Bretagne Occidentale, 29238 Brest, France
| | | | - Simon Rit
- Univ Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, UJM-Saint Étienne, CNRS, Inserm, CREATIS UMR 5220, U1294, F-69373, Lyon, France
| | - Alessandro Perelli
- Department of Biomedical Engineering, School of Science and Engineering, University of Dundee, DD1 4HN, UK
| | - Mengzhou Li
- Biomedical Imaging Center, Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Guobao Wang
- Department of Radiology, University of California Davis Health, Sacramento, USA
| | - Jian Zhou
- CTIQ, Canon Medical Research USA, Inc., Vernon Hills, 60061, USA
| | - Ge Wang
- Biomedical Imaging Center, Rensselaer Polytechnic Institute, Troy, New York, USA
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Hoche C, Henderson A, Ifergan H, Gaudron M, Magni C, Maldonado I, Cottier JP, Pasi M, Boulouis G, Cohen C. Determinants and Clinical Relevance of Iodine Contrast Extravasation after Endovascular Thrombectomy: A Dual-Energy CT Study. AJNR Am J Neuroradiol 2023; 45:30-36. [PMID: 38323978 PMCID: PMC10756568 DOI: 10.3174/ajnr.a8081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 10/29/2023] [Indexed: 02/08/2024]
Abstract
BACKGROUND AND PURPOSE Iodine contrast extravasation (ICE) is common in patients with acute ischemic stroke (AIS) after endovascular-thrombectomy (EVT). The aim of our study was to evaluate the incidence of ICE assessed by dual-energy CT (DECT), its determinants, and associations with clinical outcome. MATERIALS AND METHODS We retrospectively examined imaging parameters and clinical factors from consecutive patients with AIS treated with EVT who had a DECT 24 hours thereafter, identified at a single academic center. Associations between ICE, clinical, imaging, and procedural parameters, as well as clinical outcome were explored by using univariable and multivariable models. RESULTS A total of 197 consecutive patients were included (period 2019-2020), of which 53 (27%) demonstrated ICE that was pure ICE in 30/53 (57%) and mixed with intracranial hemorrhage (ICH) in 23/53 (43%). Low initial-ASPECTS, high per-procedural-contrast volume injected, and high admission-glycemia were independently associated with ICE (respectively, OR = 0.43, 95% CI, 0.16-1.13, P = .047; OR = 1.02, 95% CI, 1.00-1.04, P = .003; OR = 8.92, 95% CI, 0.63-125.77, P = .043). ICE was independently associated with ICH (P = .047), but not with poorer clinical outcome (6-month mRS >2, P = .223). Univariate analysis demonstrated that low ADC, higher ischemic volume, ICA occlusion, mass effect, longer procedure duration, combined thrombectomy technique, higher number of device passes, and lower recanalization rate were associated with ICE (respectively, P = .002; <.001; .002; <.001; .002; 0.011; <0.001; 0.015). CONCLUSIONS ICE evaluated with DECT is a relatively frequent finding after EVT, present in almost one-third of patients. Lower admission ASPECTS, higher glycemia, and high contrast volume injected per procedure were associated with ICE. We also found an association between ICE and ICH, confirming blood-brain barrier alteration as a major determinant of ICH.
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Affiliation(s)
- Clémence Hoche
- Neurology (C.H., M.G., M.P.), University Hospital of Tours, Tours, France
| | - Alba Henderson
- Department of Diagnostic Neuroradiology (A.H., C.M., C.C.), University Regional Hospital of Orleans, Orléans, France
| | - Héloïse Ifergan
- From the Departments of Diagnostic and Interventional Neuroradiology (H.I., J.-P.C.,G.B.), University Hospital of Tours, Tours, France
| | - Marie Gaudron
- Neurology (C.H., M.G., M.P.), University Hospital of Tours, Tours, France
| | - Christophe Magni
- Department of Diagnostic Neuroradiology (A.H., C.M., C.C.), University Regional Hospital of Orleans, Orléans, France
| | | | - Jean-Philippe Cottier
- From the Departments of Diagnostic and Interventional Neuroradiology (H.I., J.-P.C.,G.B.), University Hospital of Tours, Tours, France
| | - Marco Pasi
- Neurology (C.H., M.G., M.P.), University Hospital of Tours, Tours, France
| | - Grégoire Boulouis
- From the Departments of Diagnostic and Interventional Neuroradiology (H.I., J.-P.C.,G.B.), University Hospital of Tours, Tours, France
| | - Clara Cohen
- Department of Diagnostic Neuroradiology (A.H., C.M., C.C.), University Regional Hospital of Orleans, Orléans, France
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Ghetti C, Ortenzia O, Bertolini M, Sceni G, Sverzellati N, Silva M, Maddalo M. Lung dual energy CT: Impact of different technological solutions on quantitative analysis. Eur J Radiol 2023; 163:110812. [PMID: 37068414 DOI: 10.1016/j.ejrad.2023.110812] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 03/30/2023] [Accepted: 04/03/2023] [Indexed: 04/19/2023]
Abstract
PURPOSE To evaluated the accuracy of spectral parameters quantification of four different CT scanners in dual energy examinations of the lung using a dedicated phantom. METHOD Measurements were made with different technologies of the same vendor: one dual source CT scanner (DSCT), one TwinBeam (i.e. split filter) and two sequential acquisition single source scanners (SSCT). Angular separation of Calcium and Iodine signals were calculated from scatter plots of low-kVp versus high-kVp HUs. Electron density (ρe), effective atomic number (Zeff) and Iodine concentration (Iconc) were measured using Syngo.via software. Accuracy (A) of ρe, Zeff and Iconc was evaluated as the absolute percentage difference (D%) between reference values and measured ones, while precision (P) was evaluated as the variability σ obtained by repeating the measurement with different acquisition/reconstruction settings. RESULTS Angular separation was significantly larger for DSCT (α = 9.7°) and for sequential SSCT (α = 9.9°) systems. TwinBeam was less performing in material separation (α = 5.0°). The lowest average A was observed for TwinBeam (Aρe = [4.7 ± 1.0], AZ = [9.1 ± 3.1], AIconc = [19.4 ± 4.4]), while the best average A was obtained for Flash (Aρe = [1.8 ± 0.4], AZ = [3.5 ± 0.7], AIconc = [7.3 ± 1.8]). TwinBeam presented inferior average P (Pρe = [0.6 ± 0.1], PZ = [1.1 ± 0.2], PIconc = [10.9 ± 4.9]), while other technologies demonstrate a comparable average. CONCLUSIONS Different technologies performed material separation and spectral parameter quantification with different degrees of accuracy and precision. DSCT performed better while TwinBeam demonstrated not excellent performance. Iodine concentration measurements exhibited high variability due to low Iodine absolute content in lung nodules, thus limiting its clinical usefulness in pulmonary applications.
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Affiliation(s)
- Caterina Ghetti
- Medical Physics Unit - University Hospital of Parma, Via Gramsci 14, 43126 Parma, Italy
| | - Ornella Ortenzia
- Medical Physics Unit - University Hospital of Parma, Via Gramsci 14, 43126 Parma, Italy.
| | - Marco Bertolini
- Medical Physics Unit - AUSL-IRCCS of Reggio Emilia, Via Amendola 2, 42122 Reggio Emilia, Italy
| | - Giada Sceni
- Medical Physics Unit - AUSL-IRCCS of Reggio Emilia, Via Amendola 2, 42122 Reggio Emilia, Italy
| | - Nicola Sverzellati
- Unit of Scienze Radiologiche, Department of Medicine and Surgery, University of Parma, Via Gramsci 14, 43126 Parma, Italy
| | - Mario Silva
- Unit of Scienze Radiologiche, Department of Medicine and Surgery, University of Parma, Via Gramsci 14, 43126 Parma, Italy
| | - Michele Maddalo
- Medical Physics Unit - University Hospital of Parma, Via Gramsci 14, 43126 Parma, Italy
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Investigating new CT contrast agents: a phantom study exploring quantification and differentiation methods for high-Z elements using dual-energy CT. Eur Radiol 2021; 31:8060-8067. [PMID: 33856524 DOI: 10.1007/s00330-021-07886-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 03/05/2021] [Accepted: 03/15/2021] [Indexed: 12/31/2022]
Abstract
OBJECTIVES To develop a dual-energy CT method for differentiating and quantifying high-Z contrast elements and to evaluate the limitations based on element concentration and atomic number by using an anthropomorphic phantom study. METHODS Mass spectrometry standards for iodine, barium, gadolinium, ytterbium, tantalum, gold, and bismuth were diluted from 10.0 to 0.3 mg/mL, placed inside 7-mL vials, and scanned with dual-energy CT using an abdominal phantom and cylindrical water-filled insert. This procedure was repeated with all seven high-Z elements at six isoattenuating values from 250 to 8 HU. Quantification accuracy was measured using a linear regression model and residual error analysis with 90% limits of agreement. The limit of detection for each element was evaluated using the limit of blank of water. Pairwise differentiation of isoattenuating vials was evaluated using AUC values and the difference in fit angles between the two elements. RESULTS Each high-Z element had a unique concentration vector in a two-dimensional plot of Compton scattering versus photoelectric effect attenuations. Mean quantification values were within ± 0.1 mg/mL of the true values for each element with no proportional bias. Limits of detection ranged from 0.35 to 0.56 mg/mL. Pairwise differentiations were proportional to the isoattenuating HU and the angle between the linear fits with mean AUC values increasing from 0.61 to 0.98 at 8 to 250 HU, respectively. CONCLUSION Dual-energy CT can differentiate and quantify isoattenuating high-Z elements. The high-attenuation characteristics and unique concentration vectors of ytterbium, tantalum, gold, and bismuth are well suited for new dual-energy CT contrast agents especially when simultaneously imaged with iodine, barium, or gadolinium. KEY POINTS • Dual-energy CT can accurately quantify high-Z contrast elements and readily differentiate iodine, barium, and gadolinium from ytterbium, tantalum, gold, and bismuth. • The differentiation and quantification capabilities for high-Z contrast elements are largely unaffected by phantom size and transaxial location within the phantom. • Potential benefits of new CT contrast agents based on these high-Z elements include alternatives for patients with iodine sensitivity, high conspicuity at both 120 and 140 kVp, simultaneous imaging of two contrast agents, and reduced injection volume.
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Body size and tube voltage dependent corrections for Hounsfield Unit in medical X-ray computed tomography: theory and experiments. Sci Rep 2020; 10:15696. [PMID: 32973237 PMCID: PMC7518275 DOI: 10.1038/s41598-020-72707-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 09/02/2020] [Indexed: 12/01/2022] Open
Abstract
The purpose of this work is to present a body size and tube voltage dependent correction scheme for the Hounsfield Unit, HU, in medical X-ray Computed Tomography imaging. Boltzmann photon transport equation was employed to study X-ray interaction with bulk water in CT imaging. Experimentally measured X-ray output in body of phantoms and attenuation cross sections of water were employed in the derivation of beam intensity in X-ray imaging. A Somatom Emotion CT scanner from Siemens and electron density phantoms from CIRS were employed to acquire CT images of different body sizes and different tissue materials located at different depths from body’s surface. Tube voltage and depth dependent effective attenuation of bulk water was found from theoretical analysis in agreement with measured size-specific correction factors for CTDIvol under different tube voltages. A size and tube voltage dependent correction scheme for the Hounsfield Unit is established. For the same tissue material, body size has much larger impact on the CT number variations than that of depth from the body surface in phantom measurements. Good results were achieved by applying the established correction scheme on the experimentally measured CT number variations under different tube voltages and body sizes.
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Li G, Dong J, Huang W, Zhang Z, Wang D, Zou M, Xu Q, Lu G, Cao Z. Establishment of a novel system for the preoperative prediction of adherent perinephric fat (APF) occurrence based on a multi-mode and multi-parameter analysis of dual-energy CT. Transl Androl Urol 2019; 8:421-431. [PMID: 31807419 DOI: 10.21037/tau.2019.09.23] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Background Adherent perinephric fat (APF) is evaluated preoperatively with the Mayo adhesive probability (MAP) scoring system using conventional single-form computed tomography (CT) images. An objective or quantitative indicator for predicting APF is urgently needed for clinical application. Methods A total of 150 patients with renal tumours who underwent laparoscopic partial nephrectomy (LPN) were retrospectively enrolled and divided into the APF group (n=100) and the non-APF group (n=50) according to surgical results. All patients underwent a renal contrast-enhanced dual-energy CT (DECT) scan. The obtained CT DICOM data were transmitted to the DECT post-processing workstation and adopted virtual non-contrast (VNC), Rho/Z Maps, and Monoenergetic Plus (mono+) modes separately to undergo a multi-parameter analysis. A logistic stepwise investigation was utilized to analyse the related risk factors. The cutoff value was determined by the Youden index. Fifty patients were prospectively enrolled to validate the constructed model. The area under the curve (AUC), sensitivity, specificity and accuracy of the model were calculated. Results The study demonstrated that age, sex, body mass index (BMI), smoking status, tumour diameter, exophytic status, degree of malignancy and posterior perinephric fat thickness were related to the occurrence of APF (P<0.05). Model 1 was selected with the contrast material (CM) parameter (cutoff point 0.5), model 2 was selected with the effective atomic number (Zeff) parameter (cutoff point 6.5), and model 3 was selected with the slope K (K) parameter (cutoff point -0.95). The AUC, sensitivity, specificity and accuracy of model 1 were 0.94, 0.94, 0.93 and 0.94, respectively; for model 2, they were 0.94, 0.93, 0.93 and 0.96, respectively; and for model 3, they were 0.92, 0.92, 0.93 and 0.92, respectively. Conclusions Multi-mode and multi-parameter models of DECT can effectively be used to predict the occurrence of APF.
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Affiliation(s)
- Guan Li
- Department of Radiology, Jinling Hospital, Nanjing Medical University, Nanjing 210002, China
| | - Jie Dong
- Department of Urology, Jinling Hospital, Nanjing Medical University, Nanjing 210002, China
| | - Wei Huang
- Department of Radiology, Jinling Hospital, Nanjing Medical University, Nanjing 210002, China
| | - Zhengyu Zhang
- Department of Urology, Jinling Hospital, Nanjing Medical University, Nanjing 210002, China
| | - Di Wang
- Department of Pathology, General Hospital of Northern Theater Command, Shenyang 110016, China
| | - Mingyu Zou
- Department of Radiology, General Hospital of Northern Theater Command, Shenyang 110016, China
| | - Qinmei Xu
- Department of Radiology, Jinling Hospital, Nanjing Medical University, Nanjing 210002, China
| | - Guangming Lu
- Department of Radiology, Jinling Hospital, Nanjing Medical University, Nanjing 210002, China
| | - Zhiqiang Cao
- Department of Urology, General Hospital of Northern Theater Command, Shenyang 110016, China
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Almqvist H, Holmin S, Mazya MV. Dual energy CT after stroke thrombectomy alters assessment of hemorrhagic complications. Neurology 2019; 93:e1068-e1075. [DOI: 10.1212/wnl.0000000000008093] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 04/16/2019] [Indexed: 11/15/2022] Open
Abstract
ObjectiveTo determine whether dual energy CT with a combined approach (cDECT) using a plain noncontrast monochromatic CT (pCT), a water-weighted image after iodine removal, and an iodine-weighted image changes the diagnosis and classification of intracranial hemorrhage (ICH) after endovascular thrombectomy (EVT) in acute ischemic stroke compared to a pCT image alone without separate water and iodine weighting.MethodDuring 2012 to 2016, 372 patients at our comprehensive stroke center underwent DECT scans within 36 hours after EVT. Two readers evaluated pCT compared to a second reading with cDECT, establishing the diagnosis of ICH and grading it per the Heidelberg and Safe Implementation of Thrombolysis in Stroke–Monitoring Study (SITS-MOST) classifications.ResultUsing cDECT changed the ICH diagnosis to contrast staining only in 34% (52 of 152), modified the ICH grade in 10% (15 of 152), and diagnosed initially undetected ICH in 2% (5 of 220). pCT alone had 95% sensitivity, 80% specificity, 66% positive predictive value, 98% negative predictive value, and 85% accuracy for ICH compared to cDECT. Interreader agreement on the presence of ICH increased with cDECT compared to pCT (Cohen κ = 0.77 [95% confidence interval 0.69–0.84] vs 0.68 [0.61–0.76]).ConclusioncDECT within 36 hours after EVT changes the radiologic report regarding posttreatment ICH in a considerable proportion of patients undergoing EVT compared to pCT alone. This could affect decision-making regarding monitoring, secondary prevention, and prognostication. The cDECT scan could improve the interpretation consistency of high-attenuating changes on post-EVT images.
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Spectral CT and its specific values in the staging of patients with non-small cell lung cancer: technical possibilities and clinical impact. Clin Radiol 2019; 74:456-466. [PMID: 30905380 DOI: 10.1016/j.crad.2019.02.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Accepted: 02/12/2019] [Indexed: 12/25/2022]
Abstract
AIM To investigate how spectral computed tomography (SCT) values impact the staging of non-small cell lung cancer (NSCLC) patients. MATERIALS AND METHODS One hundred and thirteen patients with confirmed NSCLC were included in a prospective cohort study. All patients underwent single-phase contrast-enhanced SCT (using the fast tube voltage switching technique, 80-140 kV). SCT values (iodine content [IC], spectral slope pitch, and radiodensity increase) of malignant tissue (primary and metastases) and lymph nodes (LNs) were measured. Adrenal masses were evaluated in a virtual non-contrast series (VNS). If pulmonary embolism was present, pulmonary perfusion was analysed as an additional finding. RESULTS Fifty-two untreated primary NSCLC lesions were evaluable. Lung adenocarcinoma had significantly higher normalised IC (NIC: 19.37) than squamous cell carcinoma (NIC: 12.03; p=0.035). Pulmonary metastases were not significantly different from benign lung nodules. A total of 126 LNs were analysed and histologically proven metastatic LNs (2.08 mg/ml) had significantly lower IC than benign LNs (2.58 mg/ml; p=0.023). Among 34 adrenal masses, VNS identified adenomas with high sensitivity (91%) and specificity (100%). In two patients, a perfusion defect due to pulmonary embolism was detected in the iodine images. CONCLUSION SCT may contribute to the differentiation of histological NSCLC subtypes and improve the identification of LN metastases. VNS differentiates adrenal adenoma from metastasis. In case of pulmonary embolism, iodine imaging can visualise associated pulmonary perfusion defects.
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Katsura M, Sato J, Akahane M, Kunimatsu A, Abe O. Current and Novel Techniques for Metal Artifact Reduction at CT: Practical Guide for Radiologists. Radiographics 2018. [PMID: 29528826 DOI: 10.1148/rg.2018170102] [Citation(s) in RCA: 165] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Artifacts caused by metallic implants appear as dark and bright streaks at computed tomography (CT), which severely degrade the image quality and decrease the diagnostic value of the examination. When x-rays pass through a metal object, depending on its size and composition, different physical effects negatively affect the measurements in the detector, most notably the effects of photon starvation and beam hardening. To improve image quality and recover information about underlying structures, several artifact reduction methods have been introduced in modern CT systems. Projection-based metal artifact reduction (MAR) algorithms act in projection space and replace corrupted projections caused by metal with interpolation from neighboring uncorrupted projections. MAR algorithms primarily suppress artifacts that are due to photon starvation. The dual-energy CT technique is characterized by data acquisition at two different energy spectra. Dual-energy CT provides synthesized virtual monochromatic images at different photon energy (kiloelectron volt) levels, and virtual monochromatic images obtained at high kiloelectron volt levels are known to reduce the effects of beam hardening. In clinical practice, although MAR algorithms can be applied after image acquisition, the decision whether to apply dual-energy CT for the patient usually needs to be made before image acquisition. Radiologists should be more familiar with the clinical and technical features of each method and should be able to choose the optimal method according to the clinical situation. ©RSNA, 2018.
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Affiliation(s)
- Masaki Katsura
- From the Department of Radiology, Graduate School of Medicine (M.K., J.S., O.A.), and the Department of Radiology, Institute of Medical Science (A.K.), the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan; and the Department of Radiology, School of Medicine, International University of Health and Welfare, Chiba, Japan (M.A.)
| | - Jiro Sato
- From the Department of Radiology, Graduate School of Medicine (M.K., J.S., O.A.), and the Department of Radiology, Institute of Medical Science (A.K.), the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan; and the Department of Radiology, School of Medicine, International University of Health and Welfare, Chiba, Japan (M.A.)
| | - Masaaki Akahane
- From the Department of Radiology, Graduate School of Medicine (M.K., J.S., O.A.), and the Department of Radiology, Institute of Medical Science (A.K.), the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan; and the Department of Radiology, School of Medicine, International University of Health and Welfare, Chiba, Japan (M.A.)
| | - Akira Kunimatsu
- From the Department of Radiology, Graduate School of Medicine (M.K., J.S., O.A.), and the Department of Radiology, Institute of Medical Science (A.K.), the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan; and the Department of Radiology, School of Medicine, International University of Health and Welfare, Chiba, Japan (M.A.)
| | - Osamu Abe
- From the Department of Radiology, Graduate School of Medicine (M.K., J.S., O.A.), and the Department of Radiology, Institute of Medical Science (A.K.), the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan; and the Department of Radiology, School of Medicine, International University of Health and Welfare, Chiba, Japan (M.A.)
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Kandathil A, Kay F, Batra K, Saboo SS, Rajiah P. Advances in Computed Tomography in Thoracic Imaging. Semin Roentgenol 2018; 53:157-170. [PMID: 29861007 DOI: 10.1053/j.ro.2018.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Asha Kandathil
- Cardiothoracic Imaging, Radiology Department, UT Southwestern Medical Center, Dallas, TX
| | - Fernando Kay
- Cardiothoracic Imaging, Radiology Department, UT Southwestern Medical Center, Dallas, TX
| | - Kiran Batra
- Cardiothoracic Imaging, Radiology Department, UT Southwestern Medical Center, Dallas, TX
| | - Sachin S Saboo
- Cardiothoracic Imaging, Radiology Department, UT Southwestern Medical Center, Dallas, TX
| | - Prabhakar Rajiah
- Cardiothoracic Imaging, Radiology Department, UT Southwestern Medical Center, Dallas, TX.
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Lambert JW, Sun Y, Ordovas KG, Gould RG, Wang S, Yeh BM. Improved Calcium Scoring at Dual-Energy Computed Tomography Angiography Using a High-Z Contrast Element and Novel Material Separation Technique. J Comput Assist Tomogr 2018; 42:459-466. [PMID: 28937491 PMCID: PMC5860919 DOI: 10.1097/rct.0000000000000676] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECTIVES The aim of this study was to compare the accuracy of existing dual-energy computed tomography (CT) angiography coronary artery calcium scoring methods to those obtained using an experimental tungsten-based contrast material and a recently described contrast material extraction process (CMEP). METHODS Phantom coronary arteries of varied diameters, with different densities and arcs of simulated calcified plaque, were sequentially filled with water, iodine, and tungsten contrast materials and scanned within a thorax phantom at rapid-kVp-switching dual-energy CT. Calcium and contrast density images were obtained by material decomposition (MD) and CMEP. Relative calcium scoring errors among the 4 reconstructed datasets were compared with a ground truth, 120-kVp dataset. RESULTS Compared with the 120-kVp dataset, tungsten CMEP showed a significantly lower mean absolute error in calcium score (6.2%, P < 0.001) than iodine CMEP, tungsten MD, and iodine MD (9.9%, 15.7%, and 40.8%, respectively). CONCLUSIONS Novel contrast elements and material separation techniques offer improved coronary artery calcium scoring accuracy and show potential to improve the use of dual-energy CT angiography in a clinical setting.
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Affiliation(s)
- Jack W Lambert
- From the University of California, San Francisco, San Francisco, CA
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13
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Abstract
OBJECTIVES Conventional material decomposition techniques for dual-energy computed tomography (CT) assume mass or volume conservation, where the CT number of each voxel is fully assigned to predefined materials. We present an image-domain contrast material extraction process (CMEP) method that preferentially extracts contrast-producing materials while leaving the remaining image intact. MATERIALS AND METHODS Image processing freeware (Fiji) is used to perform consecutive arithmetic operations on a dual-energy ratio map to generate masks, which are then applied to the original images to generate material-specific images. First, a low-energy image is divided by a high-energy image to generate a ratio map. The ratio map is then split into material-specific masks. Ratio intervals known to correspond to particular materials (eg, iodine, calcium) are assigned a multiplier of 1, whereas ratio values in between these intervals are assigned linear gradients from 0 to 1. The masks are then multiplied by an original CT image to produce material-specific images. The method was tested quantitatively at dual-source CT and rapid kVp-switching CT (RSCT) with phantoms using pure and mixed formulations of tungsten, calcium, and iodine. Errors were evaluated by comparing the known material concentrations with those derived from the CMEP material-specific images. Further qualitative evaluation was performed in vivo at RSCT with a rabbit model using identical CMEP parameters to the phantom. Orally administered tungsten, vascularly administered iodine, and skeletal calcium were used as the 3 contrast materials. RESULTS All 5 material combinations-tungsten, iodine, and calcium, and mixtures of tungsten-calcium and iodine-calcium-showed distinct dual-energy ratios, largely independent of material concentration at both dual-source CT and RSCT. The CMEP was successful in both phantoms and in vivo. For pure contrast materials in the phantom, the maximum error between the known and CMEP-derived material concentrations was 0.9 mg/mL, 24.9 mg/mL, and 0.4 mg/mL for iodine, calcium, and tungsten respectively. Mixtures of iodine and calcium showed the highest discrepancies, which reflected the sensitivity of iodine to the image-type chosen for the extraction of the final material-specific image. The rabbit model was able to clearly show the 3 extracted material phases, vascular iodine, oral tungsten, and skeletal calcium. Some skeletal calcium was misassigned to the extracted iodine image; however, this did not impede the depiction of the vasculature. CONCLUSIONS The CMEP is a straightforward, image-domain approach to extract material signal at dual-energy CT. It has particular value for separation of experimental high-Z contrast elements from conventional iodine contrast or calcium, even when the exact attenuation coefficient profiles of desired contrast materials may be unknown. The CMEP is readily implemented in the image-domain within freeware, and can be adapted for use with images from multiple vendors.
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Norman N, Dimmock M, Lee K, Graham J, Bassed R. The applicability of Dual-Energy Computed Tomography (DECT) in forensic odontology – A review. ACTA ACUST UNITED AC 2017. [DOI: 10.1016/j.jofri.2017.07.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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15
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Stevenson AW, Di Lillo F. Estimating the absolute flux distribution for a synchrotron X-ray beam using ionization-chamber measurements with various filters. JOURNAL OF SYNCHROTRON RADIATION 2017; 24:939-953. [PMID: 28862616 DOI: 10.1107/s1600577517009274] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 06/20/2017] [Indexed: 06/07/2023]
Abstract
It is shown that an extensive set of accurate ionization-chamber measurements with a primary polychromatic synchrotron X-ray beam transmitted through various filter combinations/thicknesses can be used to quite effectively estimate the absolute flux distribution. The basic technique is simple but the `inversion' of the raw data to extract the flux distribution is a fundamentally ill-posed problem. It is demonstrated, using data collected at the Imaging and Medical Beamline (IMBL) of the Australian Synchrotron, that the absolute flux can be quickly and reliably estimated if a suitable choice of filters is made. Results are presented as a function of the magnetic field (from 1.40 to 4.00 T) of the superconducting multi-pole wiggler insertion device installed at IMBL. A non-linear least-squares refinement of the data is used to estimate the incident flux distribution and then comparison is made with calculations from the programs SPECTRA, XOP and spec.exe. The technique described is important not only in estimating flux itself but also for a variety of other, derived, X-ray properties such as beam quality, power density and absorbed-dose rate. The applicability of the technique with a monochromatic X-ray beam for which there is significant harmonic contamination is also demonstrated. Whilst absolute results can also be derived in this monochromatic beam case, relative (integrated) flux values are sufficient for our primary aim of establishing reliable determinations of the percentages of the various harmonic components.
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Affiliation(s)
- Andrew W Stevenson
- Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia
| | - Francesca Di Lillo
- Department of Physics `Ettore Pancini', Università di Napoli Federico II, Naples, Italy
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16
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The Effect of Patient Diameter on the Dual-Energy Ratio of Selected Contrast-Producing Elements. J Comput Assist Tomogr 2017; 41:505-510. [PMID: 27824676 DOI: 10.1097/rct.0000000000000557] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
OBJECTIVES The aim of this study was to assess whether the low- to high-kVp computed tomography (CT) number ratio at dual-energy CT is affected by changes in patient diameter. METHODS Seven contrast-producing elements were housed sequentially within an abdomen phantom. Fat rings enlarged the phantom diameter from 26 to 44 cm. The phantom was scanned using single-energy CT at tube potentials of 80 and 140 kVp and rapid-kVp-switching dual-energy CT. RESULTS CT numbers decreased proportionally (∼20% CT number reduction for smallest to largest phantom diameters) for low- and high-energy acquisitions but resulted in consistent dual-energy ratios for each contrast element. For 17 of 21 material pair combinations, the dual-energy ratio ranges of the two elements did not overlap, implying that discrimination should remain possible for these material pairs at all patient sizes. CONCLUSIONS The dual-energy ratio for different contrast materials is largely unaffected by changes in phantom diameter. This should allow for robust separation of most contrast material combinations irrespective of patient size.
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Multicolor spectral photon-counting computed tomography: in vivo dual contrast imaging with a high count rate scanner. Sci Rep 2017; 7:4784. [PMID: 28684756 PMCID: PMC5500581 DOI: 10.1038/s41598-017-04659-9] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 05/31/2017] [Indexed: 11/23/2022] Open
Abstract
A new prototype spectral photon-counting computed tomography (SPCCT) based on a modified clinical CT system has been developed. SPCCT analysis of the energy composition of the transmitted x-ray spectrum potentially allows simultaneous dual contrast agent imaging, however, this has not yet been demonstrated with such a system. We investigated the feasibility of using this system to distinguish gold nanoparticles (AuNP) and an iodinated contrast agent. The contrast agents and calcium phosphate were imaged in phantoms. Conventional CT, gold K-edge, iodine and water images were produced and demonstrated accurate discrimination and quantification of gold and iodine concentrations in a phantom containing mixtures of the contrast agents. In vivo experiments were performed using New Zealand White rabbits at several times points after injections of AuNP and iodinated contrast agents. We found that the contrast material maps clearly differentiated the distributions of gold and iodine in the tissues allowing quantification of the contrast agents’ concentrations, which matched their expected pharmacokinetics. Furthermore, rapid, repetitive scanning was done, which allowed measurement of contrast agent kinetics with high temporal resolution. In conclusion, a clinical scale, high count rate SPCCT system is able to discriminate gold and iodine contrast media in different organs in vivo.
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Lombardo F, Bonatti M, Zamboni G, Avesani G, Oberhofer N, Bonelli M, Pycha A, Pozzi Mucelli R, Bonatti G. Uric acid versus non-uric acid renal stones: in vivo differentiation with spectral CT. Clin Radiol 2017; 72:490-496. [DOI: 10.1016/j.crad.2017.01.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 12/21/2016] [Accepted: 01/31/2017] [Indexed: 11/25/2022]
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Saba L, Sanfilippo R, Balestrieri A, Zaccagna F, Argiolas GM, Suri JS, Montisci R. Relationship between Carotid Computed Tomography Dual-Energy and Brain Leukoaraiosis. J Stroke Cerebrovasc Dis 2017; 26:1824-1830. [PMID: 28527587 DOI: 10.1016/j.jstrokecerebrovasdis.2017.04.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Revised: 03/27/2017] [Accepted: 04/14/2017] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND The purpose of this study was to assess if there is a correlation between the carotid computed tomography (CT) Hounsfield unit (HU)-based plaque attenuation values measured using dual-energy CT (DECT) scanner and brain leukoaraiosis (LA). METHODS Fifty consecutive patients (34 males, 16 females; mean age, 69 years; age range, 46-84 years) who underwent carotid CT and brain magnetic resonance imaging were included in the study. CT examinations were performed with a DECT scanner, and LA lesion volume quantification was performed using a semiautomated segmentation technique. RESULTS We found an inverse statistically significant correlation between the HU-based carotid artery plaque attenuation and the LA lesion volume. Because of the presence of calcified plaques, a second model was calculated at low kiloelectron volt levels from 66 to 100 and 100 kV by taking into consideration the fatty and mixed plaques, and this further led to the associations between HU-based attenuation and LA volume in brain and vascular territories. CONCLUSIONS The results of our study suggest that the associations between HU attenuation of the carotid artery plaques (with the exclusion of calcified plaques) and the volume of LA are emphasized at low keV energy levels.
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Affiliation(s)
- Luca Saba
- Department of Radiology, Azienda Ospedaliero Universitaria (A.O.U.), Cagliari 09045, Italy.
| | - Roberto Sanfilippo
- Department of Vascular Surgery, Azienda Ospedaliero Universitaria (A.O.U.), Cagliari 09045, Italy
| | - Antonella Balestrieri
- Department of Radiology, Azienda Ospedaliero Universitaria (A.O.U.), Cagliari 09045, Italy
| | - Fulvio Zaccagna
- Department of Radiology, University of Cambridge School of Clinical Medicine, Cambridge, CB2 0QQ, UK
| | | | - Jasjit S Suri
- Stroke Diagnostic and Monitoring Division, AtheroPoint LLC, Roseville, CA, USA
| | - Roberto Montisci
- Department of Vascular Surgery, Azienda Ospedaliero Universitaria (A.O.U.), Cagliari 09045, Italy
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Yeh BM, FitzGerald PF, Edic PM, Lambert JW, Colborn RE, Marino ME, Evans PM, Roberts JC, Wang ZJ, Wong MJ, Bonitatibus PJ. Opportunities for new CT contrast agents to maximize the diagnostic potential of emerging spectral CT technologies. Adv Drug Deliv Rev 2017; 113:201-222. [PMID: 27620496 PMCID: PMC5344792 DOI: 10.1016/j.addr.2016.09.001] [Citation(s) in RCA: 108] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 08/30/2016] [Accepted: 09/01/2016] [Indexed: 12/15/2022]
Abstract
The introduction of spectral CT imaging in the form of fast clinical dual-energy CT enabled contrast material to be differentiated from other radiodense materials, improved lesion detection in contrast-enhanced scans, and changed the way that existing iodine and barium contrast materials are used in clinical practice. More profoundly, spectral CT can differentiate between individual contrast materials that have different reporter elements such that high-resolution CT imaging of multiple contrast agents can be obtained in a single pass of the CT scanner. These spectral CT capabilities would be even more impactful with the development of contrast materials designed to complement the existing clinical iodine- and barium-based agents. New biocompatible high-atomic number contrast materials with different biodistribution and X-ray attenuation properties than existing agents will expand the diagnostic power of spectral CT imaging without penalties in radiation dose or scan time.
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Affiliation(s)
- Benjamin M Yeh
- Department of Radiology and Biomedical Imaging, University of California San Francisco, 505 Parnassus Ave, San Francisco, CA 94143-0628, United States.
| | - Paul F FitzGerald
- General Electric Global Research, One Research Circle, Niskayuna, NY 12309, United States
| | - Peter M Edic
- General Electric Global Research, One Research Circle, Niskayuna, NY 12309, United States
| | - Jack W Lambert
- Department of Radiology and Biomedical Imaging, University of California San Francisco, 505 Parnassus Ave, San Francisco, CA 94143-0628, United States
| | - Robert E Colborn
- General Electric Global Research, One Research Circle, Niskayuna, NY 12309, United States
| | - Michael E Marino
- General Electric Global Research, One Research Circle, Niskayuna, NY 12309, United States
| | - Paul M Evans
- GE Healthcare Life Sciences, The Grove Centre, White Lion Road, Amersham, Buckinghamshire HP7 9LL, United Kingdom
| | - Jeannette C Roberts
- General Electric Global Research, One Research Circle, Niskayuna, NY 12309, United States
| | - Zhen J Wang
- Department of Radiology and Biomedical Imaging, University of California San Francisco, 505 Parnassus Ave, San Francisco, CA 94143-0628, United States
| | - Margaret J Wong
- Department of Radiology and Biomedical Imaging, University of California San Francisco, 505 Parnassus Ave, San Francisco, CA 94143-0628, United States
| | - Peter J Bonitatibus
- General Electric Global Research, One Research Circle, Niskayuna, NY 12309, United States
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21
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van Hamersvelt RW, Willemink MJ, de Jong PA, Milles J, Vlassenbroek A, Schilham AMR, Leiner T. Feasibility and accuracy of dual-layer spectral detector computed tomography for quantification of gadolinium: a phantom study. Eur Radiol 2017; 27:3677-3686. [PMID: 28124106 PMCID: PMC5544796 DOI: 10.1007/s00330-017-4737-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 12/12/2016] [Accepted: 01/03/2017] [Indexed: 01/24/2023]
Abstract
Objectives The aim of this study was to evaluate the feasibility and accuracy of dual-layer spectral detector CT (SDCT) for the quantification of clinically encountered gadolinium concentrations. Methods The cardiac chamber of an anthropomorphic thoracic phantom was equipped with 14 tubular inserts containing different gadolinium concentrations, ranging from 0 to 26.3 mg/mL (0.0, 0.1, 0.2, 0.4, 0.5, 1.0, 2.0, 3.0, 4.0, 5.1, 10.6, 15.7, 20.7 and 26.3 mg/mL). Images were acquired using a novel 64-detector row SDCT system at 120 and 140 kVp. Acquisitions were repeated five times to assess reproducibility. Regions of interest (ROIs) were drawn on three slices per insert. A spectral plot was extracted for every ROI and mean attenuation profiles were fitted to known attenuation profiles of water and pure gadolinium using in-house-developed software to calculate gadolinium concentrations. Results At both 120 and 140 kVp, excellent correlations between scan repetitions and true and measured gadolinium concentrations were found (R > 0.99, P < 0.001; ICCs > 0.99, CI 0.99–1.00). Relative mean measurement errors stayed below 10% down to 2.0 mg/mL true gadolinium concentration at 120 kVp and below 5% down to 1.0 mg/mL true gadolinium concentration at 140 kVp. Conclusion SDCT allows for accurate quantification of gadolinium at both 120 and 140 kVp. Lowest measurement errors were found for 140 kVp acquisitions. Key Points • Gadolinium quantification may be useful in patients with contraindication to iodine. • Dual-layer spectral detector CT allows for overall accurate quantification of gadolinium. • Interscan variability of gadolinium quantification using SDCT material decomposition is excellent.
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Affiliation(s)
- Robbert W van Hamersvelt
- Department of Radiology, University Medical Center Utrecht, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands.
| | - Martin J Willemink
- Department of Radiology, University Medical Center Utrecht, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands
| | - Pim A de Jong
- Department of Radiology, University Medical Center Utrecht, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands
| | - Julien Milles
- CT Clinical Science, Philips HealthCare, Best, The Netherlands
| | | | - Arnold M R Schilham
- Department of Radiology, University Medical Center Utrecht, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands
| | - Tim Leiner
- Department of Radiology, University Medical Center Utrecht, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands
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Fleischmann D, Chin AS, Molvin L, Wang J, Hallett R. Computed Tomography Angiography: A Review and Technical Update. Radiol Clin North Am 2016; 54:1-12. [PMID: 26654388 DOI: 10.1016/j.rcl.2015.09.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The principles of computed tomography angiography (CTA) remain the following with modern-day computed tomography (CT): high-resolution volumetric CT data acquisition, imaging at maximum contrast medium enhancement, and subsequent angiographic two- and three-dimensional visualization. One prerequisite for adapting CTA to ever evolving CT technology is understanding the principle rules of contrast medium enhancement. Four key rules of early arterial contrast dynamics can help one understand the relationship between intravenously injected contrast medium and the resulting time-dependent arterial enhancement. The technical evolution of CT has continued with many benefits for CT angiography. Well-informed adaptations of CTA principles allow for leveraging of these innovations for the benefit of patients with cardiovascular diseases.
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Affiliation(s)
- Dominik Fleischmann
- Stanford University 3D Imaging Laboratory, Department of Radiology, Computed Tomography, Stanford Hospital and Clinics, Stanford University School of Medicine, 300 Pasteur Drive, Room S-072, Stanford, CA 94305-5105, USA.
| | - Anne S Chin
- University of Montreal, 3840 Saint Urbain, Montreal, Quebec H2W 1T6, Canada
| | - Lior Molvin
- Department of Radiology, Stanford Health Care, Stanford Medicine Imaging Center, 451 Sherman Avenue, Palo Alto, CA 94306, USA
| | - Jia Wang
- Environmental Health and Safety, 480 Oak Road, Stanford, CA 94305, USA
| | - Richard Hallett
- Department of Radiology, Stanford University School of Medicine, 300 Pasteur Drive, Room S-072, Stanford, CA 94305-5105, USA
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Rathnayake S, Mongan J, Torres AS, Colborn R, Gao DW, Yeh BM, Fu Y. In vivo comparison of tantalum, tungsten, and bismuth enteric contrast agents to complement intravenous iodine for double-contrast dual-energy CT of the bowel. CONTRAST MEDIA & MOLECULAR IMAGING 2016; 11:254-61. [PMID: 26892945 DOI: 10.1002/cmmi.1687] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 11/23/2015] [Accepted: 01/16/2016] [Indexed: 01/06/2023]
Abstract
To assess the ability of dual-energy CT (DECT) to separate intravenous contrast of bowel wall from intraluminal contrast, we scanned 16 rabbits on a clinical DECT scanner: n = 3 using only iodinated intravenous contrast, and n = 13 double-contrast enhanced scans using iodinated intravenous contrast and experimental enteric non-iodinated contrast agents in the bowel lumen (five bismuth, four tungsten, and four tantalum based). Representative image pairs from conventional CT images and DECT iodine density maps of small bowel (116 pairs from 232 images) were viewed by four abdominal imaging attending radiologists to independently score each comparison pair on a visual analog scale (-100 to +100%) for (1) preference in small bowel wall visualization and (2) preference in completeness of intraluminal enteric contrast subtraction. Median small bowel wall visualization was scored 39 and 42 percentage points (95% CI 30-44% and 36-45%, both p < 0.001) higher for double-contrast DECT than for conventional CT with enteric tungsten and tantalum contrast, respectively. Median small bowel wall visualization for double-contrast DECT was scored 29 and 35 percentage points (95% CI 20-35% and 33-39%, both p < 0.001) higher with enteric tungsten and tantalum, respectively, than with bismuth contrast. Median completeness of intraluminal enteric contrast subtraction in double-contrast DECT iodine density maps was scored 28 and 29 percentage points (95% CI 15-31% and 28-33%, both p < 0.001) higher with enteric tungsten and tantalum, respectively, than with bismuth contrast. Results suggest that in vivo double-contrast DECT with iodinated intravenous and either tantalum- or tungsten-based enteric contrast provides better visualization of small bowel than conventional CT. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Samira Rathnayake
- Department of Radiology and Biomedical Imaging, University of California San Francisco (UCSF), San Francisco, CA, USA
| | - John Mongan
- Department of Radiology and Biomedical Imaging, University of California San Francisco (UCSF), San Francisco, CA, USA
| | - Andrew S Torres
- GE Global Research, 1 Research Circle, Niskayuna, New York, USA
| | - Robert Colborn
- GE Global Research, 1 Research Circle, Niskayuna, New York, USA
| | - Dong-Wei Gao
- Department of Radiology and Biomedical Imaging, University of California San Francisco (UCSF), San Francisco, CA, USA
| | - Benjamin M Yeh
- Department of Radiology and Biomedical Imaging, University of California San Francisco (UCSF), San Francisco, CA, USA
| | - Yanjun Fu
- Department of Radiology and Biomedical Imaging, University of California San Francisco (UCSF), San Francisco, CA, USA
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Danad I, Ó Hartaigh B, Min JK. Dual-energy computed tomography for detection of coronary artery disease. Expert Rev Cardiovasc Ther 2015; 13:1345-56. [PMID: 26549789 DOI: 10.1586/14779072.2015.1102055] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Recent technological advances in computed tomography (CT) technology have fulfilled the prerequisites for the cardiac application of dual-energy CT (DECT) imaging. By exploiting the unique characteristics of materials when exposed to two different x-ray energies, DECT holds great promise for the diagnosis and management of coronary artery disease. It allows for the assessment of myocardial perfusion to discern the hemodynamic significance of coronary disease and possesses high accuracy for the detection and characterization of coronary plaques, while facilitating reductions in radiation dose. As such, DECT enabled cardiac CT to advance beyond the mere detection of coronary stenosis expanding its role in the evaluation and management of coronary atherosclerosis.
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Affiliation(s)
- Ibrahim Danad
- a Department of Radiology, Weill Cornell Medical College , Dalio Institute of Cardiovascular Imaging, NewYork-Presbyterian Hospital , New York , NY , USA
| | - Bríain Ó Hartaigh
- a Department of Radiology, Weill Cornell Medical College , Dalio Institute of Cardiovascular Imaging, NewYork-Presbyterian Hospital , New York , NY , USA
| | - James K Min
- a Department of Radiology, Weill Cornell Medical College , Dalio Institute of Cardiovascular Imaging, NewYork-Presbyterian Hospital , New York , NY , USA
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Faby S, Kuchenbecker S, Sawall S, Simons D, Schlemmer HP, Lell M, Kachelrieß M. Performance of today's dual energy CT and future multi energy CT in virtual non-contrast imaging and in iodine quantification: A simulation study. Med Phys 2015; 42:4349-66. [DOI: 10.1118/1.4922654] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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