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Rajiah P, Abbara S, Halliburton SS. Spectral detector CT for cardiovascular applications. Diagn Interv Radiol 2017; 23:187-193. [PMID: 28302592 PMCID: PMC5410998 DOI: 10.5152/dir.2016.16255] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 07/26/2016] [Accepted: 09/17/2016] [Indexed: 01/23/2023]
Abstract
Spectral detector computed tomography (SDCT) is a novel technology that uses two layers of detectors to simultaneously collect low and high energy data. Spectral data is used to generate conventional polyenergetic images as well as dedicated spectral images including virtual monoenergetic and material composition (iodine-only, virtual unenhanced, effective atomic number) images. This paper provides an overview of SDCT technology and a description of some spectral image types. The potential utility of SDCT for cardiovascular imaging and the impact of this new technology on radiation and contrast dose are discussed through presentation of initial patient studies performed on a SDCT scanner. The value of SDCT for salvaging suboptimal studies including those with poor contrast-enhancement or beam hardening artifacts through retrospective reconstruction of spectral data is discussed. Additionally, examples of specific benefits for the evaluation of aortic disease, imaging before transcatheter aortic valve implantation, evaluation of pulmonary veins pre- and post-pulmonary radiofrequency ablation, evaluation of coronary artery lumen, assessment of myocardial perfusion, detection of pulmonary embolism, and characterization of incidental findings are presented.
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Affiliation(s)
- Prabhakar Rajiah
- From the Department of Radiology (P.R. , S.A.) Southwestern Medical Center, Dallas, Texas, USA; Philips Healthcare (S.S.H.) Cleveland, Ohio, USA
| | - Suhny Abbara
- From the Department of Radiology (P.R. , S.A.) Southwestern Medical Center, Dallas, Texas, USA; Philips Healthcare (S.S.H.) Cleveland, Ohio, USA
| | - Sandra Simon Halliburton
- From the Department of Radiology (P.R. , S.A.) Southwestern Medical Center, Dallas, Texas, USA; Philips Healthcare (S.S.H.) Cleveland, Ohio, USA
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Müller K, Datta S, Ahmad M, Choi JH, Moore T, Pung L, Niebler C, Gold GE, Maier A, Fahrig R. Interventional dual-energy imaging-Feasibility of rapid kV-switching on a C-arm CT system. Med Phys 2017; 43:5537. [PMID: 27782692 DOI: 10.1118/1.4962929] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
PURPOSE In the last years, dual-energy CT imaging has shown clinical value, thanks to its ability to differentiate materials based on their atomic number and to exploit different properties of images acquired at two different energies. C-arm CT systems are used to guide procedures in the interventional suite. Until now, there are no commercially available systems that employ dual-energy material decomposition. This paper explores the feasibility of implementing a fast kV-switching technique on a clinically available angiographic system for acquiring dual-energy C-arm CT images. METHODS As an initial proof of concept, a fast kV-switching approach was implemented on an angiographic C-arm system and the peak tube voltage during 3D rotational scans was measured. The tube voltage measurements during fast kV-switching scans were compared to corresponding measurements on kV-constant scans. Additionally, to prove stability of the requested exposure parameters, the accuracy of the delivered tube current and pulse width were also recorded and compared. In a first phantom experiment, the voxel intensity values of the individual tube voltage components of the fast kV-switching scans were compared to their corresponding kV-constant scans. The same phantom was used for a simple material decomposition between different iodine concentrations and pure water using a fast kV-switching protocol of 81 and 125 kV. In the last experiment, the same kV-switching protocol as in the phantom scan was used in an in vivo pig study to demonstrate the clinical feasibility. RESULTS During rapid kV-switching acquisitions, the measured tube voltage of the x-ray tube during fast switching scans has an absolute deviation of 0.23 ± 0.13 kV compared to the measured tube voltage produced during kV-constant acquisitions. The stability of the peak tube voltage over different scan requests was about 0.10 kV for the low and 0.46 for the high energy kV-switching scans and less than 0.1 kV for kV-constant scans, indicating slightly lower stability for kV-switching scans. The tube current resulted in a relative deviation of -1.6% for the low and 6.6% overestimation for the high tube voltage of the kV-switching scans compared to the kV-constant scans. The pulse width showed no deviation for the longer pulse width and only minor deviations (0.02 ± 0.02 ms) for the shorter pulse widths compared to the kV-constant scans. The phantom experiment using different iodine concentrations showed an accurate correlation (R2 > 0.99) between the extracted intensity values in the kV-switching and kV-constant reconstructed volumes, and allows for an automatic differentiation between contrast concentration down to 10% (350 mg/ml iodine) and pure water under low-noise conditions. Preliminary results of iodine and soft tissue separation showed also promising results in the first in vivo pig study. CONCLUSIONS The feasibility of dual-energy imaging using a fast kV-switching method on an angiographic C-arm CT system was investigated. Direct measurements of beam quality in the x-ray field demonstrate the stability of the kV-switching method. Phantom and in vivo experiments showed that images did not deviate from those of corresponding kV-constant scans. All performed experiments confirmed the capability of performing fast kV-switching scans on a clinically available C-arm CT system. More complex material decomposition tasks and postprocessing steps will be part of future investigations.
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Affiliation(s)
- K Müller
- Radiological Sciences Lab, Stanford University, Stanford, California 94305
| | - S Datta
- Siemens Medical Solutions, Inc., Malvern, Pennsylvania 19355
| | - M Ahmad
- Radiological Sciences Lab, Stanford University, Stanford, California 94305
| | - J-H Choi
- Radiological Sciences Lab, Stanford University, Stanford, California 94305
| | - T Moore
- Siemens Medical Solutions, Inc., Malvern, Pennsylvania 19355
| | - L Pung
- Siemens Medical Solutions, Inc., Malvern, Pennsylvania 19355
| | - C Niebler
- Department of Electrical Engineering, Technische Hochschule Nürnberg, Nürnberg 90489, Germany
| | - G E Gold
- Department of Radiology, Stanford University Stanford, California 94305; Department of Orthopaedic Surgery, Stanford University, Stanford, California 94305; and Department of Bioengineering, Stanford University, Stanford, California 94305
| | - A Maier
- Pattern Recognition Lab, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen 91058, Germany
| | - R Fahrig
- Radiological Sciences Lab, Stanford University, Stanford, California 94305
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Machida H, Tanaka I, Fukui R, Shen Y, Ishikawa T, Tate E, Ueno E. Dual-Energy Spectral CT: Various Clinical Vascular Applications. Radiographics 2017; 36:1215-32. [PMID: 27399244 DOI: 10.1148/rg.2016150185] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Single-source dual-energy (DE) computed tomography (CT) with fast switching of tube voltage allows projection-based image reconstruction, substantial reduction of beam-hardening effects, reconstruction of accurate monochromatic images and material decomposition images (MDIs), and detailing of material composition by using x-ray spectral information. In vascular applications, DE CT is expected to overcome limitations of standard single-energy CT angiography, including patient exposure to nephrotoxic contrast medium and carcinogenic radiation, insufficient contrast vascular enhancement, interference from metallic and beam-hardening artifacts and severe vessel calcification, and limited tissue characterization and perfusion assessment. Acquisition of low-energy monochromatic images and iodine/water MDIs can reasonably reduce contrast agent dose and improve vessel enhancement. Acquisition of virtual noncontrast images, such as water/iodine MDIs, can reduce overall radiation exposure by replacing true noncontrast CT in each examination. Acquisition of monochromatic images by using metal artifact reduction software or acquisition of iodine/water MDIs can reduce metal artifacts with preserved or increased vessel contrast, and subtraction of monochromatic images between two energy levels can subtract coils composed of dense metallic materials. Acquisition of iodine/calcium (ie, hydroxyapatite) MDIs permits subtraction of vessel calcification and improves vessel lumen delineation. Sensitive detection of lipid-rich plaque can be achieved by using fat/water MDIs, the spectral Hounsfield unit curve (energy level vs CT attenuation), and a histogram of effective atomic numbers included in an image. Various MDIs are useful for accurate differentiation among materials with high attenuation values, including contrast medium, calcification, and fresh hematoma. Iodine/water MDIs are used to assess organ perfusion, such as in the lungs and myocardium. Understanding these DE CT techniques enhances the value of CT for vascular applications. (©)RSNA, 2016.
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Affiliation(s)
- Haruhiko Machida
- From the Department of Radiology, Tokyo Women's Medical University, Medical Center East, 2-1-10 Nishiogu, Arakawa-ku, Tokyo 116-8567, Japan
| | - Isao Tanaka
- From the Department of Radiology, Tokyo Women's Medical University, Medical Center East, 2-1-10 Nishiogu, Arakawa-ku, Tokyo 116-8567, Japan
| | - Rika Fukui
- From the Department of Radiology, Tokyo Women's Medical University, Medical Center East, 2-1-10 Nishiogu, Arakawa-ku, Tokyo 116-8567, Japan
| | - Yun Shen
- From the Department of Radiology, Tokyo Women's Medical University, Medical Center East, 2-1-10 Nishiogu, Arakawa-ku, Tokyo 116-8567, Japan
| | - Takuya Ishikawa
- From the Department of Radiology, Tokyo Women's Medical University, Medical Center East, 2-1-10 Nishiogu, Arakawa-ku, Tokyo 116-8567, Japan
| | - Etsuko Tate
- From the Department of Radiology, Tokyo Women's Medical University, Medical Center East, 2-1-10 Nishiogu, Arakawa-ku, Tokyo 116-8567, Japan
| | - Eiko Ueno
- From the Department of Radiology, Tokyo Women's Medical University, Medical Center East, 2-1-10 Nishiogu, Arakawa-ku, Tokyo 116-8567, Japan
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Weiss J, Notohamiprodjo M, Bongers M, Schabel C, Mangold S, Nikolaou K, Bamberg F, Othman AE. Noise-optimized monoenergetic post-processing improves visualization of incidental pulmonary embolism in cancer patients undergoing single-pass dual-energy computed tomography. Radiol Med 2017; 122:280-287. [PMID: 28070843 DOI: 10.1007/s11547-016-0717-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 12/12/2016] [Indexed: 11/28/2022]
Abstract
PURPOSE To evaluate noise-optimized monoenergetic postprocessing of dual-energy CT (DE-CT) on image quality in patients with incidental pulmonary embolism in single-pass portal-venous phase CT (CTpv). MATERIALS AND METHODS 20 Consecutive patients with incidental pulmonary embolism in contrast-enhanced oncological follow-up DE-CTpv examination were included in this study. Images were acquired with a 3rd generation DE-CT system in DE mode (100/Sn150 kV) and activated tube current modulation 90 s after contrast agent administration. Subsequently, virtual monoenergetic images (MEI+) were reconstructed at five different keV levels (40, 55, 70, 85, 100) and compared to the standard linearly blended (M_0.8) CTpv images. Image quality was assessed qualitatively (vascular contrast and detectability of embolism, image noise, iodine influx artifact; two independent readers; 5-point Likert scale; 5 = excellent) and quantitatively by calculating signal-to-noise (SNR) and contrast-to-noise ratios (CNR). RESULTS Highest vessel contrast and highest detectability of embolism were observed in MEI+ at 40 keV (4.7 ± 0.4) and 55 keV (4.2 ± 0.6) with significant differences as compared to CTpv (3.6 ± 0.5) and high keV reconstructions (70, 85, 100; p ≤ 0.01). Image noise significantly increased at 40 keV MEI+ compared to all other MEI+ reconstructions and CTpv (p < 0.001). SNR and CNR calculations were highest at 40 keV MEI+ followed by 55 keV and CTpv with significant differences to high keV MEI+ (85-100). CONCLUSIONS Computed MEI+ at low keV levels allow for improved vessel contrast and visualisation of incidental pulmonary embolism in patients with portal-venous phase CT scans by substantially increasing CNR and SNR.
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Affiliation(s)
- Jakob Weiss
- Department of Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany.
| | - Mike Notohamiprodjo
- Department of Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany
| | - Malte Bongers
- Department of Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany
| | - Christoph Schabel
- Department of Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany
| | - Stefanie Mangold
- Department of Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany
| | - Konstantin Nikolaou
- Department of Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany
| | - Fabian Bamberg
- Department of Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany
| | - Ahmed E Othman
- Department of Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany
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Multidetector (64+) Computed Tomography Angiography of the Lower Limb in Symptomatic Peripheral Arterial Disease. J Comput Assist Tomogr 2017; 41:327-333. [DOI: 10.1097/rct.0000000000000494] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Yuan J, Usman A, Das T, Patterson AJ, Gillard JH, Graves MJ. Imaging Carotid Atherosclerosis Plaque Ulceration: Comparison of Advanced Imaging Modalities and Recent Developments. AJNR Am J Neuroradiol 2016; 38:664-671. [PMID: 28007772 DOI: 10.3174/ajnr.a5026] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Atherosclerosis remains the leading cause of long-term mortality and morbidity worldwide, despite remarkable advancement in its management. Vulnerable atherosclerotic plaques are principally responsible for thromboembolic events in various arterial territories such as carotid, coronary, and lower limb vessels. Carotid plaque ulceration is one of the key features associated with plaque vulnerability and is considered a notable indicator of previous plaque rupture and possible future cerebrovascular events. Multiple imaging modalities have been used to assess the degree of carotid plaque ulceration for diagnostic and research purposes. Early diagnosis and management of carotid artery disease could prevent further cerebrovascular events. In this review, we highlight the merits and limitations of various imaging techniques for identifying plaque ulceration.
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Affiliation(s)
- J Yuan
- From the Department of Radiology (J.Y., A.U., J.H.G., M.J.G.), University of Cambridge, Cambridge, UK
| | - A Usman
- From the Department of Radiology (J.Y., A.U., J.H.G., M.J.G.), University of Cambridge, Cambridge, UK
| | - T Das
- Department of Radiology (T.D., A.J.P., M.J.G.), Cambridge University Hospitals National Health Service Foundation Trust, Cambridge, UK
| | - A J Patterson
- Department of Radiology (T.D., A.J.P., M.J.G.), Cambridge University Hospitals National Health Service Foundation Trust, Cambridge, UK
| | - J H Gillard
- From the Department of Radiology (J.Y., A.U., J.H.G., M.J.G.), University of Cambridge, Cambridge, UK
| | - M J Graves
- From the Department of Radiology (J.Y., A.U., J.H.G., M.J.G.), University of Cambridge, Cambridge, UK.,Department of Radiology (T.D., A.J.P., M.J.G.), Cambridge University Hospitals National Health Service Foundation Trust, Cambridge, UK
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Spinal dual-energy computed tomography: improved visualisation of spinal tumorous growth with a noise-optimised advanced monoenergetic post-processing algorithm. Neuroradiology 2016; 58:1093-1102. [DOI: 10.1007/s00234-016-1733-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 07/19/2016] [Indexed: 01/14/2023]
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58
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Martin SS, Albrecht MH, Wichmann JL, Hüsers K, Scholtz JE, Booz C, Bodelle B, Bauer RW, Metzger SC, Vogl TJ, Lehnert T. Value of a noise-optimized virtual monoenergetic reconstruction technique in dual-energy CT for planning of transcatheter aortic valve replacement. Eur Radiol 2016; 27:705-714. [DOI: 10.1007/s00330-016-4422-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 02/10/2016] [Accepted: 05/19/2016] [Indexed: 10/21/2022]
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Quantitative and Qualitative Comparison of Single-Source Dual-Energy Computed Tomography and 120-kVp Computed Tomography for the Assessment of Pancreatic Ductal Adenocarcinoma. J Comput Assist Tomogr 2016; 39:907-13. [PMID: 26295192 DOI: 10.1097/rct.0000000000000295] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
PURPOSE The aim of this study was to compare contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) between pancreatic-phase dual-energy computed tomography (DECT) and 120-kVp CT for pancreatic ductal adenocarcinoma (PDA). MATERIALS AND METHODS Seventy-eight patients underwent multiphasic pancreatic imaging protocols for PDA (40, DECT; 38, 120-kVp CT [control]). Using pancreatic phase, CNR and SNR for PDA were obtained for DECT at monochromatic energies 50 through 80 keV, iodine material density images, and 120-kVp images. Using a 5-point scale (1, excellent; 5, markedly limited), images were qualitatively assessed by 2 radiologists in consensus for PDA detection, extension, vascular involvement, and noise. Wilcoxon signed rank and 2-sample tests were used to compare the qualitative measures, CNR and SNR, for DECT and 120-kVp images. Bonferroni correction was applied. RESULTS Iodine material density image had significantly higher CNR and SNR for PDA than any monochromatic energy images (P < 0.0001) and the 120-kVp images. Qualitatively, 70-keV images were rated highest in the categories of tumor extension and vascular invasion and were similar to 120-kVp images. CONCLUSIONS Our results indicate that DECT improves PDA lesion conspicuity compared with routine 120-kVp CT, which may allow for better detection of PDA.
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Stefanidis K, Sayer C, Vlahos I. Multidetector dual-energy CT evaluation of combined partial anomalous pulmonary venous return and bronchial atresia. BJR Case Rep 2016; 2:20150282. [PMID: 30364369 PMCID: PMC6195915 DOI: 10.1259/bjrcr.20150282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 10/05/2015] [Accepted: 10/28/2015] [Indexed: 11/24/2022] Open
Abstract
Partial anomalous venous return (PAPVR) and bronchial atresia (BA) represent rare congenital abnormalities of the lung. Missed diagnosis and misdiagnosis are very common in these patients. Although usually distinct entities, it appears that, in rare cases, they may co-exist owing to inter-related complex embryogenic development. We report a case of a 59-year-old male with both PAPVR and BA that were incidentally detected during a CT pulmonary angiogram and review the literature to suggest the pathogenetic developmental mechanism for this entity. This case demonstrates the utility of multidetector dual-energy CT in delineating the vascular and bronchial anatomy of this complex lung and vascular anomaly. Although uncommon, radiologists should be aware of PAPVR and BA and the coexistence of these two rare lung congenital abnormalities.
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Affiliation(s)
| | - Charles Sayer
- Radiology Department, St George's Hospital, London, UK
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61
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White Paper of the Society of Computed Body Tomography and Magnetic Resonance on Dual-Energy CT, Part 2. J Comput Assist Tomogr 2016; 40:846-850. [DOI: 10.1097/rct.0000000000000539] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Price M, Patino M, Sahani D. Computed Tomography Angiography of the Hepatic, Pancreatic, and Splenic Circulation. Radiol Clin North Am 2015; 54:55-70. [PMID: 26654391 DOI: 10.1016/j.rcl.2015.08.009] [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: 10/22/2022]
Abstract
Multidetector computed tomography angiography (MDCTA) has become a routine imaging tool to assess visceral vascular anatomy and abdominal parenchymal pathology. Enhanced temporal resolution and rapid acquisition allow for precise delineation of arterial and venous anatomy. The excellent spatial resolution permits assessment of small parenchyma lesions and vasculature. The ability of CT to rapidly acquire data and reconstruct with thinner slices allows robust 3D mapping using maximum intensity projection before definitive surgical or interventional therapy. Emerging novel techniques of image acquisition offer sensitive methods for detecting enhancement and allow for virtual imaging subtraction, all while limiting the total radiation burden.
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Affiliation(s)
- Melissa Price
- Division of Abdominal Imaging, Massachusetts General Hospital, 55 Fruit Street, White 270, Boston, MA 02114, USA
| | - Manuel Patino
- Division of Abdominal Imaging, Massachusetts General Hospital, 55 Fruit Street, White 270, Boston, MA 02114, USA
| | - Dushyant Sahani
- Division of Abdominal Imaging, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, White 270, Boston, MA 02114, USA.
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Optimal Contrast of Cerebral Dual-Energy Computed Tomography Angiography in Patients With Spontaneous Subarachnoid Hemorrhage. J Comput Assist Tomogr 2015; 40:48-52. [PMID: 26571057 PMCID: PMC4718178 DOI: 10.1097/rct.0000000000000336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Objective The aim of this study was to investigate the image quality of cerebral dual-energy computed tomography (CT) angiography using a nonlinear image blending technique as compared with the conventional linear blending method in patients with spontaneous subarachnoid hemorrhage (SAH). Methods A retrospective review of 30 consecutive spontaneous SAH patients who underwent a dual-source, dual-energy (80 kV and Sn140 kV mode) cerebral CT angiography was performed with permission from hospital ethical committee. Optimized images using nonlinear blending method were generated and compared with the 0.6 linear blending images by evaluating cerebral artery enhancement, attenuation of SAH, image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR), respectively. Two neuroradiologists independently assessed subjective vessel visualization per segment using a 5-point scale. Results The nonlinear blending images showed higher cerebral artery enhancement (307.24 ± 58.04 Hounsfield unit [HU]), lower attenuation of SAH (67.07 ± 6.79 HU), and image noise (7.18 ± 1.20 HU), thus achieving better SNR (43.92 ± 11.14) and CNR (34.34 ± 10.25), compared with those of linear blending images (235.47 ± 46.45 HU for cerebral artery enhancement, 70.00 ± 6.41 HU for attenuation of SAH, 8.39 ± 1.25 HU for image noise, 28.86 ± 8.43 for SNR, and 20.37 ± 7.74 for CNR) (all P < 0.01). The segmental scorings of the nonlinear blending image (31.6% segments with a score of 5, 57.4% segments with a score of 4, 11% segments with a score of 3) ranged significantly higher than those of linear blending images (11.5% segments with a score of 5, 77.5% segments with a score of 4, 11% segments with a score of 3) (P < 0.01). The interobserver agreement was good (κ = 0.762), and intraobserver agreement was excellent for both observers (κ = 0.844 and 0.858, respectively). Conclusions The nonlinear image blending technique improved vessel visualization of cerebral dual-energy CT angiography by optimizing contrast enhancement in spontaneous SAH patients.
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Kok M, Turek J, Mihl C, Reinartz SD, Gohmann RF, Nijssen EC, Kats S, van Ommen VG, Kietselaer BLJH, Wildberger JE, Das M. Low contrast media volume in pre-TAVI CT examinations. Eur Radiol 2015; 26:2426-35. [PMID: 26560728 PMCID: PMC4927596 DOI: 10.1007/s00330-015-4080-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 09/07/2015] [Accepted: 10/22/2015] [Indexed: 01/02/2023]
Abstract
PURPOSE To evaluate image quality using reduced contrast media (CM) volume in pre-TAVI assessment. METHODS Forty-seven consecutive patients referred for pre-TAVI examination were evaluated. Patients were divided into two groups: group 1 BMI < 28 kg/m(2) (n = 29); and group 2 BMI > 28 kg/m(2) (n = 18). Patients received a combined scan protocol: retrospective ECG-gated helical CTA of the aortic root (80kVp) followed by a high-pitch spiral CTA (group 1: 70 kV; group 2: 80 kVp) from aortic arch to femoral arteries. All patients received one bolus of CM (300 mgI/ml): group 1: volume = 40 ml; flow rate = 3 ml/s, group 2: volume = 53 ml; flow rate = 4 ml/s. Attenuation values (HU) and contrast-to-noise ratio (CNR) were measured at the levels of the aortic root (helical) and peripheral arteries (high-pitch). Diagnostic image quality was considered sufficient at attenuation values > 250HU and CNR > 10. RESULTS Diagnostic image quality for TAVI measurements was obtained in 46 patients. Mean attenuation values and CNR (HU ± SD) at the aortic root (helical) were: group 1: 381 ± 65HU and 13 ± 8; group 2: 442 ± 68HU and 10 ± 5. At the peripheral arteries (high-pitch), mean values were: group 1: 430 ± 117HU and 11 ± 6; group 2: 389 ± 102HU and 13 ± 6. CONCLUSION CM volume can be substantially reduced using low kVp protocols, while maintaining sufficient image quality for the evaluation of aortic root and peripheral access sites. KEY POINTS • Image quality could be maintained using low kVp scan protocols. • Low kVp protocols reduce contrast media volume by 34-67 %. • Less contrast media volume lowers the risk of contrast-induced nephropathy.
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Affiliation(s)
- Madeleine Kok
- Department of Radiology, Maastricht University Medical Center, P. Debyelaan 25, PO Box 5800, 6202 AZ, Maastricht, The Netherlands
- CARIM School for Cardiovascular Diseases, Maastricht University Medical Center, P. Debyelaan 25, PO Box 5800, 6202 AZ, Maastricht, The Netherlands
| | - Jakub Turek
- Department of Radiology, Maastricht University Medical Center, P. Debyelaan 25, PO Box 5800, 6202 AZ, Maastricht, The Netherlands
| | - Casper Mihl
- Department of Radiology, Maastricht University Medical Center, P. Debyelaan 25, PO Box 5800, 6202 AZ, Maastricht, The Netherlands
- CARIM School for Cardiovascular Diseases, Maastricht University Medical Center, P. Debyelaan 25, PO Box 5800, 6202 AZ, Maastricht, The Netherlands
| | - Sebastian D Reinartz
- Department of Diagnostic and Interventional Radiology, University Hospital, RWTH Aachen University, Pauwelsstr. 30, 52074, Aachen, Germany
| | - Robin F Gohmann
- Department of Diagnostic and Interventional Radiology, University Hospital, RWTH Aachen University, Pauwelsstr. 30, 52074, Aachen, Germany
| | - Estelle C Nijssen
- Department of Radiology, Maastricht University Medical Center, P. Debyelaan 25, PO Box 5800, 6202 AZ, Maastricht, The Netherlands
| | - Suzanne Kats
- Department of Cardiothoracic Surgery, Maastricht University Medical Center, P. Debyelaan 25, PO Box 5800, 6202 AZ, Maastricht, The Netherlands
| | - Vincent G van Ommen
- Department of Cardiology, Maastricht University Medical Center MUMC+, P. Debyelaan 25, PO Box 5800, 6202 AZ, Maastricht, The Netherlands
| | - Bas L J H Kietselaer
- CARIM School for Cardiovascular Diseases, Maastricht University Medical Center, P. Debyelaan 25, PO Box 5800, 6202 AZ, Maastricht, The Netherlands
- Department of Cardiology, Maastricht University Medical Center MUMC+, P. Debyelaan 25, PO Box 5800, 6202 AZ, Maastricht, The Netherlands
| | - Joachim E Wildberger
- Department of Radiology, Maastricht University Medical Center, P. Debyelaan 25, PO Box 5800, 6202 AZ, Maastricht, The Netherlands
- CARIM School for Cardiovascular Diseases, Maastricht University Medical Center, P. Debyelaan 25, PO Box 5800, 6202 AZ, Maastricht, The Netherlands
| | - Marco Das
- Department of Radiology, Maastricht University Medical Center, P. Debyelaan 25, PO Box 5800, 6202 AZ, Maastricht, The Netherlands.
- CARIM School for Cardiovascular Diseases, Maastricht University Medical Center, P. Debyelaan 25, PO Box 5800, 6202 AZ, Maastricht, The Netherlands.
- Maastricht University Medical Center, P. Debyelaan 25, PO Box 5800, 6202 AZ, Maastricht, The Netherlands.
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Almutairi A, Sun Z, Poovathumkadavi A, Assar T. Dual Energy CT Angiography of Peripheral Arterial Disease: Feasibility of Using Lower Contrast Medium Volume. PLoS One 2015; 10:e0139275. [PMID: 26418007 PMCID: PMC4587806 DOI: 10.1371/journal.pone.0139275] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 09/09/2015] [Indexed: 01/31/2023] Open
Abstract
OBJECTIVE One of the main drawbacks associated with Dual Energy Computed Tomography Angiography (DECTA) is the risk of developing contrast medium-induced nephropathy (CIN). The aim of the present study was firstly, to design an optimal CT imaging protocol by determining the feasibility of using a reduced contrast medium volume in peripheral arterial DECTA, and secondly, to compare the results with those obtained from using routine contrast medium volume. METHODS Thirty four patients underwent DECTA for the diagnosis of peripheral arterial disease. They were randomly divided into two groups: Group 1 (routine contrast volume group) with n = 17, injection rate 4-5 ml/s, and 1.5 ml/kg of contrast medium, and Group 2 ((low contrast volume group), with n = 17, injection rate 4-5ml/s, and contrast medium volume 0.75 ml/kg. A fast kilovoltage-switching 64-slice CT scanner in the dual-energy mode was employed for the study. A total of 6 datasets of monochromatic images at 50, 55, 60, 65, 70 and 75 keV levels were reconstructed with adaptive statistical iterative reconstruction (ASIR) at 50%. A 4-point scale was the tool for qualitative analysis of results. The two groups were compared and assessed quantitatively for image quality on the basis of signal-to-noise ratio (SNR) and contrast-to-noise-ratio (CNR). Radiation and contrast medium doses were also compared. RESULTS The overall mean CT attenuation and mean noise for all lower extremity body parts was significantly lower for the low volume contrast group (p<0.001), and varied significantly between groups (p = 0.001), body parts (p<0.001) and keVs (p<0.001). The interaction between group body parts was significant with CT attenuation and CNR (p = 0.002 and 0.003 respectively), and marginally significant with SNR (p = 0.047), with minimal changes noticed between the two groups. Group 2 (low contrast volume group) displayed the lowest image noise between 65 and 70 keV, recorded the highest SNR and CNR at 65 keV, and produced significantly lower results with respect to contrast medium volume and duration of contrast injection (p<0.001). The effect of radiation dose was not statistically significant between the two groups. CONCLUSIONS DECTA images created at 65 keV and 50% ASIR with low contrast medium volume protocol, yielded results that were comparable to routine contrast medium volume, with acceptable diagnostic images produced during the evaluation of peripheral arteries.
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Affiliation(s)
- Abdulrahman Almutairi
- Department of Medical Radiation Sciences, School of Science, Curtin University, Perth, 6845, Western Australia, Australia
- Department of Medical Imaging, King Fahad Specialist Hospital, Dammam, 31444, Saudi Arabia
| | - Zhonghua Sun
- Department of Medical Radiation Sciences, School of Science, Curtin University, Perth, 6845, Western Australia, Australia
- * E-mail:
| | | | - Tarek Assar
- Department of Medical Imaging, King Fahad Specialist Hospital, Dammam, 31444, Saudi Arabia
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Andrew M, John H. The challenge of coronary calcium on coronary computed tomographic angiography (CCTA) scans: effect on interpretation and possible solutions. Int J Cardiovasc Imaging 2015; 31 Suppl 2:145-57. [DOI: 10.1007/s10554-015-0773-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 09/15/2015] [Indexed: 11/25/2022]
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A Method to Improve Electron Density Measurement of Cone-Beam CT Using Dual Energy Technique. BIOMED RESEARCH INTERNATIONAL 2015; 2015:858907. [PMID: 26346510 PMCID: PMC4540959 DOI: 10.1155/2015/858907] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 07/19/2015] [Accepted: 07/22/2015] [Indexed: 01/24/2023]
Abstract
Purpose. To develop a dual energy imaging method to improve the accuracy of electron density measurement with a cone-beam CT (CBCT) device. Materials and Methods. The imaging system is the XVI CBCT system on Elekta Synergy linac. Projection data were acquired with the high and low energy X-ray, respectively, to set up a basis material decomposition model. Virtual phantom simulation and phantoms experiments were carried out for quantitative evaluation of the method. Phantoms were also scanned twice with the high and low energy X-ray, respectively. The data were decomposed into projections of the two basis material coefficients according to the model set up earlier. The two sets of decomposed projections were used to reconstruct CBCT images of the basis material coefficients. Then, the images of electron densities were calculated with these CBCT images. Results. The difference between the calculated and theoretical values was within 2% and the correlation coefficient of them was about 1.0. The dual energy imaging method obtained more accurate electron density values and reduced the beam hardening artifacts obviously. Conclusion. A novel dual energy CBCT imaging method to calculate the electron densities was developed. It can acquire more accurate values and provide a platform potentially for dose calculation.
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Albrecht MH, Scholtz JE, Hüsers K, Beeres M, Bucher AM, Kaup M, Martin SS, Fischer S, Bodelle B, Bauer RW, Lehnert T, Vogl TJ, Wichmann JL. Advanced image-based virtual monoenergetic dual-energy CT angiography of the abdomen: optimization of kiloelectron volt settings to improve image contrast. Eur Radiol 2015; 26:1863-70. [PMID: 26334508 DOI: 10.1007/s00330-015-3970-2] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 08/03/2015] [Accepted: 08/06/2015] [Indexed: 11/28/2022]
Abstract
OBJECTIVES To compare quantitative image quality parameters in abdominal dual-energy computed tomography angiography (DE-CTA) using an advanced image-based (Mono+) reconstruction algorithm for virtual monoenergetic imaging and standard DE-CTA. METHODS Fifty-five patients (36 men; mean age, 64.2 ± 12.7 years) who underwent abdominal DE-CTA were retrospectively included. Mono + images were reconstructed at 40, 50, 60, 70, 80, 90 and 100 keV levels and as standard linearly blended M_0.6 images (60 % 100 kV, 40 % 140 kV). The contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) of the common hepatic (CHA), splenic (SA), superior mesenteric (SMA) and left renal arteries (LRA) were objectively measured. RESULTS Mono+ DE-CTA series showed a statistically superior CNR for 40, 50, 60, 70 and 80 keV (P < 0.031) compared to M_0.6 images for all investigated arteries except SMA at 80 keV (P = 0.08). CNR at 40 keV revealed a mean relative increase of 287.7 % compared to linearly blended images among all assessed arteries (P < 0.001). SNR of Mono+ images was consistently significantly higher at 40, 50, 60 and 70 keV compared to M_0.6 for CHA and SA (P < 0.009). CONCLUSIONS Compared to linearly blended images, Mono+ reconstructions at low keV levels of abdominal DE-CTA datasets significantly improve quantitative image quality. KEY POINTS • Mono+ combines increased attenuation with reduced image noise compared to standard DE-CTA. • Mono+ shows superior contrast-to-noise ratios at low keV compared to linearly-blended images. • Contrast-to-noise ratio in monoenergetic DE-CTA peaks at 40 keV. • Mono+ reconstructions significantly improve quantitative image quality at low keV levels.
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Affiliation(s)
- Moritz H Albrecht
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany.
| | - Jan-Erik Scholtz
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Kristina Hüsers
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Martin Beeres
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Andreas M Bucher
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Moritz Kaup
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Simon S Martin
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Sebastian Fischer
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Boris Bodelle
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Ralf W Bauer
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Thomas Lehnert
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Thomas J Vogl
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Julian L Wichmann
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
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Multidetector CT and three-dimensional CT angiography of upper extremity arterial injury. Emerg Radiol 2014; 22:269-82. [DOI: 10.1007/s10140-014-1288-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Accepted: 11/21/2014] [Indexed: 02/07/2023]
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Clinical applications of dual-energy CT in head and neck imaging. Eur Arch Otorhinolaryngol 2014; 273:547-53. [PMID: 25472819 DOI: 10.1007/s00405-014-3417-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 11/26/2014] [Indexed: 10/24/2022]
Abstract
Dual-energy CT provides insights into the material properties of the tissues and can differentiate between tissues that have similar attenuation on conventional, single energy CT imaging. It has several useful and promising applications in head and neck imaging that an otolaryngologist could use to deliver improved clinical care. These applications include metal artifact reduction, atherosclerotic plaque and tumor characterization, detection of parathyroid lesions, and delineation of paranasal sinus ventilation. Dual-energy CT can potentially improve image quality, reduce radiation dose, and provide specific diagnostic information for certain head and neck lesions. This article reviews some current and potential otolaryngology applications of dual-energy CT.
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Lv P, Lin J, Guo D, Liu H, Tang X, Fu C, Hu J. Detection of carotid artery stenosis: a comparison between 2 unenhanced MRAs and dual-source CTA. AJNR Am J Neuroradiol 2014; 35:2360-5. [PMID: 25104291 DOI: 10.3174/ajnr.a4073] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
BACKGROUND AND PURPOSE Dual-source CTA and black-blood MRA are recently developed techniques for evaluating carotid stenosis. The purpose of this study was to compare dual-source CTA with black-blood MRA and conventional TOF MRA in both detecting carotid stenosis by using DSA as a reference standard and demonstrating plaque morphology. MATERIALS AND METHODS Thirty patients with suspected carotid artery stenosis underwent unenhanced MRA by using black-blood and TOF MRA and dual-source CTA. Source images from unenhanced MRAs and dual-source CTA were reconstructed with MIP or curved planar reconstruction. The degree of carotid artery stenosis was measured, and plaque surface morphology at the stenosis was analyzed and compared among different techniques. RESULTS Good correlation was observed for measuring the degree of carotid stenosis among dual-source CTA, black-blood MRA, TOF MRA, and DSA. Sensitivity and specificity for detecting severe stenosis were 100% and 97% with dual-source CTA, 100% and 95% with black-blood MRA, and 79% and 95% with TOF MRA. None of the 3 technologies resulted in stenosis of <50% being overestimated. Plaque surface irregularity or ulceration was more frequently detected with dual-source CTA and black-blood MRA than with TOF MRA and DSA. CONCLUSIONS This preliminary study shows that black-blood MRA is a promising technique, comparable with dual-source CTA and DSA, but better than TOF MRA, in the evaluation of carotid stenosis. Unlike dual-source CTA, black-blood MRA requires no intravenous contrast or radiation.
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Affiliation(s)
- P Lv
- From the Department of Radiology (P.L., J.L., H.L.), Zhongshan Hospital, Shanghai Medical College of Fudan University and Shanghai Institute of Medical Imaging, Shanghai, China
| | - J Lin
- From the Department of Radiology (P.L., J.L., H.L.), Zhongshan Hospital, Shanghai Medical College of Fudan University and Shanghai Institute of Medical Imaging, Shanghai, China
| | - D Guo
- Department of Vascular Surgery (D.G., X.T.), Zhongshan Hospital, Fudan University and Institute of Vascular Surgery, Shanghai, China
| | - H Liu
- From the Department of Radiology (P.L., J.L., H.L.), Zhongshan Hospital, Shanghai Medical College of Fudan University and Shanghai Institute of Medical Imaging, Shanghai, China
| | - X Tang
- Department of Vascular Surgery (D.G., X.T.), Zhongshan Hospital, Fudan University and Institute of Vascular Surgery, Shanghai, China
| | - C Fu
- Siemens Shenzhen Magnetic Resonance (C.F.), Shenzhen, China
| | - J Hu
- Department of Cardiology (J.H.), Zhongshan Hospital, Fudan University, Shanghai, China
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Carotid artery stents on CT angiography: In vitro comparison of different stent designs and sizes using 16-, 64- and 320-row CT scanners. J Neuroradiol 2014; 41:259-68. [DOI: 10.1016/j.neurad.2013.10.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2013] [Revised: 10/08/2013] [Accepted: 10/22/2013] [Indexed: 11/18/2022]
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Clark ZE, Bolus DN, Little MD, Morgan DE. Abdominal rapid-kVp-switching dual-energy MDCT with reduced IV contrast compared to conventional MDCT with standard weight-based IV contrast: an intra-patient comparison. ACTA ACUST UNITED AC 2014; 40:852-8. [PMID: 25261257 DOI: 10.1007/s00261-014-0253-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Fuentes-Orrego JM, Pinho D, Kulkarni NM, Agrawal M, Ghoshhajra BB, Sahani DV. New and Evolving Concepts in CT for Abdominal Vascular Imaging. Radiographics 2014; 34:1363-1384. [DOI: 10.1148/rg.345130070] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
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Oh LCW, Lau KK, Devapalasundaram A, Buchan K, Ardley N, Huynh M. Efficacy of 'fine' focal spot imaging in CT abdominal angiography. Eur Radiol 2014; 24:3010-6. [PMID: 25097134 DOI: 10.1007/s00330-014-3368-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 06/26/2014] [Accepted: 07/21/2014] [Indexed: 11/29/2022]
Abstract
OBJECTIVES To assess the efficacy of fine focal spot imaging in calcification beam-hardening artefact reduction and vessel clarity on CT abdominal angiography (CTAA). METHODS Adult patients of any age and gender who presented for CTAA were included. Thirty-nine patients were examined with a standard focal spot size (SFSS) of 1 × 1 mm in the first 3 months while 31 consecutive patients were examined with a fine focal spot size (FFSS) of 1 × 0.5 mm in the following 3 months. Vessel clarity and calcification beam-hardening artefacts of the abdominal aorta, celiac axis, superior mesenteric artery, inferior mesenteric artery, renal arteries, and iliac arteries were assessed using a 5-point grading scale by two blinded radiologists randomly. RESULTS Cohen's Kappa test indicated that on average, there was substantial agreement among reviewers for vessel wall clarity and calcification artefact grading. Mann-Whitney test showed that there was a significant difference between the two groups, with FFSS performing significantly better for vessel clarity (U, 6481.50; p < 0.001; r, 0.73) and calcification artefact reduction (U, 1916; p < 0.001; r, 0.77). CONCLUSION Fine focus CT angiography produces images with better vessel wall clarity and less vessel calcification beam-hardening artefact. KEY POINTS Focal spot size affects the spatial resolution of a CT system. Fine focus CTAA produces images with improved vessel wall clarity. Fine focus CTAA is associated with fewer calcification beam-hardening artefacts. Fine focus CTAA may improve accuracy in assessment of luminal stenosis.
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Affiliation(s)
- Lawrence Chia Wei Oh
- Department of Diagnostic Imaging, Monash Health, 246 Clayton Road, Clayton, 3168, Victoria, Australia,
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Incidental adrenal lesions detected on enhanced abdominal dual-energy CT: can the diagnostic workup be shortened by the implementation of virtual unenhanced images? Eur J Radiol 2014; 83:1746-51. [PMID: 25064663 DOI: 10.1016/j.ejrad.2014.06.017] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 06/11/2014] [Accepted: 06/14/2014] [Indexed: 10/25/2022]
Abstract
OBJECTIVE To determine whether post-processing of the data from portal-phase enhanced dual-energy CT (DECT), with or without the addition of a late enhanced phase acquisition, may enable characterization of adrenal lesions without the need for acquisition of pre-contrast images. MATERIALS AND METHODS Twenty-two patients with 24 adrenal lesions underwent unenhanced, venous and delayed phase DECT. Of these lesions, 20 were found to be adrenal adenomas, on the basis of histopathology, unenhanced attenuation values between 0 and -10 HU, or stability over at least 6 months. For all 24 lesions, true and virtual unenhanced attenuation values were measured based on the data of the portal (VNCp) and the delayed (VNCd) DECT acquisition. The absolute washout values based on the true non-contrast (TNC) and the VNCp and VNCd image series were also measured. The washout was also calculated based on the iodine concentration measured from both contrast-enhanced acquisitions. RESULTS Mean virtual unenhanced attenuation values of all lesions calculated from the portal phase images was 12.6 HU, and was 4.02 HU higher than the values based on true unenhanced images (p=0.020). Washout values calculated from virtual unenhanced attenuation based on the VNCp were also significantly different (p=0.0304) while those calculated from VNCd and from iodine concentration correlated with the corresponding values based on the true unenhanced values (p>0.999). CONCLUSIONS Our data indicate that attenuation values of adrenal adenomas based on virtual unenhanced images are significantly higher than those obtained with true unenhanced images. An incidental adrenal lesion with a virtual unenhanced attenuation lower than 10 HU can thus be safely characterized as an adenoma.
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Abstract
Recent technologic advances in computed tomography (CT)--enabling the nearly simultaneous acquisition of clinical images using two different x-ray energy spectra--have sparked renewed interest in dual-energy CT. By interrogating the unique characteristics of different materials at different x-ray energies, dual-energy CT can be used to provide quantitative information about tissue composition, overcoming the limitations of attenuation-based conventional single-energy CT imaging. In the past few years, intensive research efforts have been devoted to exploiting the unique and powerful opportunities of dual-energy CT for a variety of clinical applications. This has led to CT protocol modifications for radiation dose reduction, improved diagnostic performance for detection and characterization of diseases, as well as image quality optimization. In this review, the authors discuss the basic principles, instrumentation and design, examples of current clinical applications in the abdomen and pelvis, and future opportunities of dual-energy CT.
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Affiliation(s)
- Daniele Marin
- From the Department of Radiology, Duke University Medical Center, Box 3808, Room 1531, Erwin Rd, Durham, NC 27710
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Moschetta M, Telegrafo M, Rella L, Stabile Ianora AA, Angelelli G. Multi-detector CT features of acute intestinal ischemia and their prognostic correlations. World J Radiol 2014; 6:130-138. [PMID: 24876917 PMCID: PMC4037539 DOI: 10.4329/wjr.v6.i5.130] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 02/08/2014] [Accepted: 03/17/2014] [Indexed: 02/06/2023] Open
Abstract
Acute intestinal ischemia is an abdominal emergency occurring in nearly 1% of patients presenting with acute abdomen. The causes can be occlusive or non occlusive. Early diagnosis is important to improve survival rates. In most cases of late or missed diagnosis, the mortality rate from intestinal infarction is very high, with a reported value ranging from 60% to 90%. Multi-detector computed tomography (MDCT) is a fundamental imaging technique that must be promptly performed in all patients with suspected bowel ischemia. Thanks to the new dedicated reconstruction program, its diagnostic potential is much improved compared to the past and currently it is superior to that of any other noninvasive technique. The increased spatial and temporal resolution, high-quality multi-planar reconstructions, maximum intensity projections, vessel probe, surface-shaded volume rending and tissue transition projections make MDCT the gold standard for the diagnosis of intestinal ischemia, with reported sensitivity, specificity, positive and negative predictive values of 64%-93%, 92%-100%, 90%-100% and 94%-98%, respectively. MDCT contributes to appropriate treatment planning and provides important prognostic information thanks to its ability to define the nature and extent of the disease. The purpose of this review is to examine the diagnostic and prognostic role of MDCT in bowel ischemia with special regard to the state of art new reconstruction software.
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Abstract
OBJECTIVE Recent technologic advances in MDCT have led to the introduction of dual-energy CT (DECT). The basic principle of DECT is to acquire images at two different energy levels simultaneously and to use the attenuation differences at these different energy levels for deriving additional information, such as virtual monochromatic images, artifact suppression, and material composition of various tissues. CONCLUSION A variety of image reconstruction and postprocessing techniques are available for better demonstration and characterization of pathologic abnormalities. DECT can provide both anatomic and functional information of different organ systems. This article focuses on the main applications of DECT in emergency radiology.
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Aran S, Shaqdan KW, Abujudeh HH. Dual-energy computed tomography (DECT) in emergency radiology: basic principles, techniques, and limitations. Emerg Radiol 2014; 21:391-405. [DOI: 10.1007/s10140-014-1208-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2014] [Accepted: 02/17/2014] [Indexed: 02/05/2023]
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Lv P, Liu J, Wu R, Hou P, Hu L, Gao J. Use of non-linear image blending with dual-energy CT improves vascular visualization in abdominal angiography. Clin Radiol 2014; 69:e93-9. [DOI: 10.1016/j.crad.2013.09.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2013] [Revised: 09/13/2013] [Accepted: 09/25/2013] [Indexed: 11/25/2022]
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Wichmann JL, Booz C, Wesarg S, Kafchitsas K, Bauer RW, Kerl JM, Lehnert T, Vogl TJ, Khan MF. Dual-energy CT-based phantomless in vivo three-dimensional bone mineral density assessment of the lumbar spine. Radiology 2014; 271:778-84. [PMID: 24475863 DOI: 10.1148/radiol.13131952] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
PURPOSE To evaluate the feasibility of phantomless in vivo dual-energy computed tomography (CT)-based three-dimensional (3D) bone mineral density (BMD) assessment in comparison with dual x-ray absorptiometry (DXA). MATERIALS AND METHODS This retrospective study was approved by the institutional review board, and the requirement to obtain informed consent was waived. Data from clinically indicated dual-energy CT and DXA examinations within 2 months, comprising the lumbar spine of 40 patients, were included. By using automated dedicated postprocessing dual-energy CT software, the trabecular bone of lumbar vertebrae L1-L4 were analyzed and segmented. A mixed-effects model was used to assess the correlations between BMD values derived from dual-energy CT and DXA. RESULTS One hundred sixty lumbar vertebrae were analyzed in 40 patients (mean age, 57.1 years; range, 24-85 years), 21 male (mean age, 54.3 years; range, 24-85 years) and 19 female (mean age, 58.5 years; range, 31-80 years). Mean BMD of L1-L4 determined with DXA was 0.995 g/cm(2), and 18 patients (45%) showed an osteoporotic BMD (T score less than -2.5) of at least two vertebrae. Mean dual-energy CT-based BMD of L1-L4 was 0.254 g/cm(3). Bland-Altman analysis with mixed effects demonstrated a lack of correlation between dual-energy CT-based and DXA-based BMD values, with a mean difference of 0.7441 and 95% limits of agreement of 0.7441 ± 0.4080. CONCLUSION Dedicated postprocessing of dual-energy CT data allows for phantomless in vivo BMD assessment of the trabecular bone of lumbar vertebrae and enables freely rotatable color-coded 3D visualization of intravertebral BMD distribution.
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Affiliation(s)
- Julian L Wichmann
- From the University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany (J.L.W., C.B., R.W.B., J.M.K., T.L., T.J.V., M.F.K.); Fraunhofer IGD, Cognitive Computing & Medical Imaging, Darmstadt, Germany (S.W.); and University Medical Center Mainz, Clinic and Policlinic for Orthopedics and Orthopedic Surgery, Mainz, Germany (K.K.)
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CT angiography of the upper extremity arterial system: Part 1-Anatomy, technique, and use in trauma patients. AJR Am J Roentgenol 2013; 201:745-52. [PMID: 24059363 DOI: 10.2214/ajr.13.11207] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
OBJECTIVE In this article, we focus on the arterial anatomy of the upper extremities, the technical aspects of upper extremity CT angiography (CTA), and CTA use in trauma patients. CONCLUSION CTA using modern MDCT scanners has evolved into a highly accurate noninvasive diagnostic tool for the evaluation of patients with abnormalities of the upper extremity arterial system.
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Sudarski S, Apfaltrer P, Nance JW, Schneider D, Meyer M, Schoenberg SO, Fink C, Henzler T. Optimization of keV-settings in abdominal and lower extremity dual-source dual-energy CT angiography determined with virtual monoenergetic imaging. Eur J Radiol 2013; 82:e574-81. [PMID: 23763858 DOI: 10.1016/j.ejrad.2013.04.040] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 04/22/2013] [Accepted: 04/23/2013] [Indexed: 12/13/2022]
Abstract
OBJECTIVES To compare objective image quality indices in dual-energy CT angiography (DE-CTA) studies of the abdomen and lower extremity using conventional polyenergetic images (PEIs) and virtual monoenergetic images (MEIs) at different kiloelectron volt (keV) levels. METHODS We retrospectively evaluated 68 dual-source DE-CTA studies. 50 patients (42 men, 71 ± 10 years) underwent abdominal DE-CTA. 18 patients (13 men, 67 ± 10 years) underwent lower extremity DE-CTA. MEIs from 40 to 120 keV were reconstructed. Signal intensity, noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were assessed in infrarenal aorta, superior mesenteric, external iliac, femoral, popliteal, and lower leg arteries. Comparisons between MEIs and PEIs were performed with Dunnett's test. RESULTS 222 arteries were evaluated. In abdominal arteries 70 keV MEIs showed statistically equal signal intensity, noise and CNR levels (+13%; +31%, -14% on average; all p>0.05) compared to PEIs; SNR was equal or slightly impaired (-7% on average; p<0.001-1.00). In lower extremity arteries 60 keV MEIs resulted in significantly higher signal intensity and CNR (+54%; +54% on average; all p<0.05) compared to PEIs at equal noise levels (+18% on average; all p>0.05) and equal or higher SNR (+49% on average; p<0.01-0.35). CONCLUSIONS Low-keV MEIs lead to equal or higher signal intensity and CNR compared to PEIs. In lower extremity DE-CTA, additional reconstruction of low-keV MEIs at 60 keV might increase diagnostic confidence.
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Affiliation(s)
- Sonja Sudarski
- Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
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