301
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Image Quality and Current Techniques for Dose Optimization in Abdominal CT: What Every Radiologist Should Know. CURRENT RADIOLOGY REPORTS 2015. [DOI: 10.1007/s40134-015-0098-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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302
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Starosolski Z, Villamizar CA, Rendon D, Paldino MJ, Milewicz DM, Ghaghada KB, Annapragada AV. Ultra High-Resolution In vivo Computed Tomography Imaging of Mouse Cerebrovasculature Using a Long Circulating Blood Pool Contrast Agent. Sci Rep 2015; 5:10178. [PMID: 25985192 PMCID: PMC4650815 DOI: 10.1038/srep10178] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 04/01/2015] [Indexed: 12/21/2022] Open
Abstract
Abnormalities in the cerebrovascular system play a central role in many neurologic diseases. The on-going expansion of rodent models of human cerebrovascular diseases and the need to use these models to understand disease progression and treatment has amplified the need for reproducible non-invasive imaging methods for high-resolution visualization of the complete cerebral vasculature. In this study, we present methods for in vivo high-resolution (19 μm isotropic) computed tomography imaging of complete mouse brain vasculature. This technique enabled 3D visualization of large cerebrovascular networks, including the Circle of Willis. Blood vessels as small as 40 μm were clearly delineated. ACTA2 mutations in humans cause cerebrovascular defects, including abnormally straightened arteries and a moyamoya-like arteriopathy characterized by bilateral narrowing of the internal carotid artery and stenosis of many large arteries. In vivo imaging studies performed in a mouse model of Acta2 mutations demonstrated the utility of this method for studying vascular morphometric changes that are practically impossible to identify using current histological methods. Specifically, the technique demonstrated changes in the width of the Circle of Willis, straightening of cerebral arteries and arterial stenoses. We believe the use of imaging methods described here will contribute substantially to the study of rodent cerebrovasculature.
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Affiliation(s)
- Zbigniew Starosolski
- 1] Edward B. Singleton Department of Pediatric Radiology, Texas Children's Hospital, Houston TX [2] Department of Radiology, Baylor College of Medicine, Houston, TX
| | - Carlos A Villamizar
- Department of Internal Medicine, University of Texas Health Science Center at Houston, Houston, TX
| | - David Rendon
- Department of Pediatrics, Baylor College of Medicine, Houston, TX
| | - Michael J Paldino
- 1] Edward B. Singleton Department of Pediatric Radiology, Texas Children's Hospital, Houston TX [2] Department of Radiology, Baylor College of Medicine, Houston, TX
| | - Dianna M Milewicz
- Department of Internal Medicine, University of Texas Health Science Center at Houston, Houston, TX
| | - Ketan B Ghaghada
- 1] Edward B. Singleton Department of Pediatric Radiology, Texas Children's Hospital, Houston TX [2] Department of Radiology, Baylor College of Medicine, Houston, TX
| | - Ananth V Annapragada
- 1] Edward B. Singleton Department of Pediatric Radiology, Texas Children's Hospital, Houston TX [2] Department of Radiology, Baylor College of Medicine, Houston, TX
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303
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Sarno A, Mettivier G, Russo P. Dedicated breast computed tomography: Basic aspects. Med Phys 2015; 42:2786-804. [DOI: 10.1118/1.4919441] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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304
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Radiation Dose Consideration in Kidney Stone CT Examinations: Integration of Iterative Reconstruction Algorithms With Routine Clinical Practice. AJR Am J Roentgenol 2015; 204:1055-63. [PMID: 25905941 DOI: 10.2214/ajr.14.13038] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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305
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Abstract
OBJECTIVE. Radiation exposure from CT examinations should be reduced to a minimum in children. Iterative reconstruction (IR) is a method to reduce image noise that can be used to improve CT image quality, thereby allowing radiation dose reduction. This article reviews the use of hybrid and model-based IRs in pediatric CT and discusses the possibilities, advantages, and disadvantages of IR in pediatric CT and the importance of radiation dose reduction for CT of children. CONCLUSION. IR is a promising and potentially highly valuable technique that can be used to substantially reduce the amount of radiation in pediatric imaging. Future research should determine the maximum achievable radiation dose reduction in pediatric CT that is possible without a loss of diagnostic image quality.
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306
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Iterative reconstruction in cardiac CT. J Cardiovasc Comput Tomogr 2015; 9:255-63. [PMID: 26088375 DOI: 10.1016/j.jcct.2015.04.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 04/15/2015] [Accepted: 04/15/2015] [Indexed: 12/29/2022]
Abstract
Iterative reconstruction (IR) has the ability to reduce image noise in CT without compromising diagnostic quality, which permits a significant reduction in effective radiation dose. This been increasingly integrated into clinical CT practice over the past 7 years and has been particularly important in the field of cardiac CT with multiple vendors introducing cardiac CT-compatible IR algorithms. The following review will summarize the principles of IR algorithms, studies validating their noise- and dose-reducing abilities, and the specific applications of IR in cardiac CT.
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307
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Fukunaga M, Onishi H, Yamamoto H. [Validation of dark band artifact reduction using artifact reduction processing methods with low-dose CT images: phantom study]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2015; 71:316-324. [PMID: 25892418 DOI: 10.6009/jjrt.2015_jsrt_71.4.316] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
PURPOSE The purpose of this study was to validate the reduction of dark band (DB) artifact using iterative reconstruction (IR) of abdomen CT. METHODS Phantoms were arranged with and without small phantom assuming arm position at the body side (Phantom-A, -B). Image reconstruction methods were derived by the following four methods: filtered back projection (FBP), IR [adaptive iterative dose reduction using three-dimensional processing: AIDR-3D (MILD)], organ specific reconstruction (OSR), and Boost-3D (Boost). We evaluated DB artifact with CT values, standard deviation (SD) values, and profile curves using the four reconstruction methods. RESULTS CT values of artifact decreased with low tube current in Phantom-A. CT values of artifact were significantly increased (15-23 HU) in OSR and Boost compared to FBP and MILD (Phantom-A). SD values of artifact improved by IR method. However, IR method was not improved to CT values decreased by artifact (Phantom-A). CT values were not changed by the difference in image reconstruction methods in Phantom-B. CONCLUSION IR method has an effect to reduce statistical noise, but reduced the CT value for DB artifact. On the other hand, the OSR and Boost methods are effective for the improvement of CT value in the DB artifact.
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Affiliation(s)
- Masaaki Fukunaga
- 1. Program in Health and Welfare Graduate School of Comprehensive Scientific Research, Prefectural University of Hiroshima, 2. Department of Radiology, Kurashiki Central Hospital
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308
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Mafalanka F, Etard C, Rehel JL, Pesenti-Rossi D, Amrar-Vennier F, Baron N, Christiaens L, Convers-Domart R, Defez D, Douek P, Gaxotte V, Georges JL, Leygnac S, Ou P, Sablayrolles JL, Salvat C, Schouman-Claeys E, Sirol M, Aubert B. Establishment of diagnostic reference levels in cardiac CT in France: a need for patient dose optimisation. RADIATION PROTECTION DOSIMETRY 2015; 164:116-119. [PMID: 25342609 DOI: 10.1093/rpd/ncu317] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The objective of this study was to propose diagnostic reference levels (DRLs) for coronary computed tomography angiography (CCTA), in the context of a large variability in patient radiation dose, and the lack of European recommendations. Volume Computed Tomography Dose Index (CTDIvol) and dose-length product (DLP) were collected from 460 CCTAs performed over a 3-month period at eight French hospitals. CCTAs (∼50 per centre) were performed using the routine protocols of the centres, and 64- to 320-detector CT scanners. ECG gating was prospective (n = 199) or retrospective (n = 261). The large gap in dose between these two modes required to propose specific DRLs: 26 and 44 mGy for CTDIvol, and 370 and 970 mGy cm for DLP, respectively. This study confirms the large variability in patient doses during CCTA and underlines the need for the optimisation of cardiac acquisition protocols. Availability of national DRLs should be mandatory in this setting.
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Affiliation(s)
- F Mafalanka
- Institut de Radioprotection et de Sureté Nucléaire, PRP-HOM/SER, BP17, Fontenay-aux-Roses 92262, France
| | - C Etard
- Institut de Radioprotection et de Sureté Nucléaire, PRP-HOM/SER, BP17, Fontenay-aux-Roses 92262, France
| | - J L Rehel
- Institut de Radioprotection et de Sureté Nucléaire, PRP-HOM/SER, BP17, Fontenay-aux-Roses 92262, France
| | | | | | - N Baron
- Hôpital Mignot, Le Chesnay, France
| | | | | | - D Defez
- Centre Hospitalier Universitaire, Lyon, France
| | - P Douek
- Centre Hospitalier Universitaire, Lyon, France
| | - V Gaxotte
- Hôpital Bichat, AP-HP, Paris, France
| | | | - S Leygnac
- Hôpital Bichat, AP-HP, Paris, France
| | - P Ou
- Hôpital Bichat, AP-HP, Paris, France
| | | | - C Salvat
- Hôpital Lariboisière, AP-HP, Paris, France
| | | | - M Sirol
- Hôpital Lariboisière, AP-HP, Paris, France
| | - B Aubert
- Institut de Radioprotection et de Sureté Nucléaire, PRP-HOM/SER, BP17, Fontenay-aux-Roses 92262, France
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309
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Dose reduction with iterative reconstruction: Optimization of CT protocols in clinical practice. Diagn Interv Imaging 2015; 96:477-86. [PMID: 25797211 DOI: 10.1016/j.diii.2015.02.007] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 02/16/2015] [Accepted: 02/17/2015] [Indexed: 01/29/2023]
Abstract
OBJECTIVES To create an adaptable and global approach for optimizing MDCT protocols by evaluating the influence of acquisition parameters and Iterative Reconstruction (IR) on dose reduction and image quality. MATERIALS AND METHODS MDCT acquisitions were performed on quality image phantom by varying kVp, mAs, and pitch for the same collimation. The raw data were reconstructed by FBP and Sinogram Affirmed Iterative Reconstruction (SAFIRE) with different reconstruction kernel and thickness. A total of 4032 combinations of parameters were obtained. Indices of quality image (image noise, NCT, CNR, SNR, NPS and MTF) were analyzed. We developed a software in order to facilitate the optimization between dose reduction and image quality. Its outcomes were verified on an adult anthropomorphic phantom. RESULTS Dose reduction resulted in the increase of image noise and the decrease of SNR and CNR. The use of IR improved these indices for the same dose without affecting NCT and MTF. The image validation was performed by the anthropomorphic phantom. The software proposed combinations of parameters to reduce doses while keeping indices of the image quality adequate. We observed a CTDIvol reduction between -44% and -83% as compared to the French diagnostic reference levels (DRL) for different anatomical localization. CONCLUSION The software developed in this study may help radiologists in selecting adequate combinations of parameters that allows to obtain an appropriate image with dose reduction.
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310
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Xu J, Fuld MK, Fung GSK, Tsui BMW. Task-based image quality evaluation of iterative reconstruction methods for low dose CT using computer simulations. Phys Med Biol 2015; 60:2881-901. [PMID: 25776521 DOI: 10.1088/0031-9155/60/7/2881] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Iterative reconstruction (IR) methods for x-ray CT is a promising approach to improve image quality or reduce radiation dose to patients. The goal of this work was to use task based image quality measures and the channelized Hotelling observer (CHO) to evaluate both analytic and IR methods for clinical x-ray CT applications. We performed realistic computer simulations at five radiation dose levels, from a clinical reference low dose D0 to 25% D0. A fixed size and contrast lesion was inserted at different locations into the liver of the XCAT phantom to simulate a weak signal. The simulated data were reconstructed on a commercial CT scanner (SOMATOM Definition Flash; Siemens, Forchheim, Germany) using the vendor-provided analytic (WFBP) and IR (SAFIRE) methods. The reconstructed images were analyzed by CHOs with both rotationally symmetric (RS) and rotationally oriented (RO) channels, and with different numbers of lesion locations (5, 10, and 20) in a signal known exactly (SKE), background known exactly but variable (BKEV) detection task. The area under the receiver operating characteristic curve (AUC) was used as a summary measure to compare the IR and analytic methods; the AUC was also used as the equal performance criterion to derive the potential dose reduction factor of IR. In general, there was a good agreement in the relative AUC values of different reconstruction methods using CHOs with RS and RO channels, although the CHO with RO channels achieved higher AUCs than RS channels. The improvement of IR over analytic methods depends on the dose level. The reference dose level D0 was based on a clinical low dose protocol, lower than the standard dose due to the use of IR methods. At 75% D0, the performance improvement was statistically significant (p < 0.05). The potential dose reduction factor also depended on the detection task. For the SKE/BKEV task involving 10 lesion locations, a dose reduction of at least 25% from D0 was achieved.
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Affiliation(s)
- Jingyan Xu
- Division of Medical Imaging Physics, The Russell H Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD 21218, USA
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311
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Hérin E, Gardavaud F, Chiaradia M, Beaussart P, Richard P, Cavet M, Deux JF, Haioun C, Itti E, Rahmouni A, Luciani A. Use of Model-Based Iterative Reconstruction (MBIR) in reduced-dose CT for routine follow-up of patients with malignant lymphoma: dose savings, image quality and phantom study. Eur Radiol 2015; 25:2362-70. [DOI: 10.1007/s00330-015-3656-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 02/03/2015] [Indexed: 11/29/2022]
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312
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Solomon J, Mileto A, Ramirez-Giraldo JC, Samei E. Diagnostic Performance of an Advanced Modeled Iterative Reconstruction Algorithm for Low-Contrast Detectability with a Third-Generation Dual-Source Multidetector CT Scanner: Potential for Radiation Dose Reduction in a Multireader Study. Radiology 2015; 275:735-45. [PMID: 25751228 DOI: 10.1148/radiol.15142005] [Citation(s) in RCA: 124] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To assess the effect of radiation dose reduction on low-contrast detectability by using an advanced modeled iterative reconstruction (ADMIRE; Siemens Healthcare, Forchheim, Germany) algorithm in a contrast-detail phantom with a third-generation dual-source multidetector computed tomography (CT) scanner. MATERIALS AND METHODS A proprietary phantom with a range of low-contrast cylindrical objects, representing five contrast levels (range, 5-20 HU) and three sizes (range, 2-6 mm) was fabricated with a three-dimensional printer and imaged with a third-generation dual-source CT scanner at various radiation dose index levels (range, 0.74-5.8 mGy). Image data sets were reconstructed by using different section thicknesses (range, 0.6-5.0 mm) and reconstruction algorithms (filtered back projection [FBP] and ADMIRE with a strength range of three to five). Eleven independent readers blinded to technique and reconstruction method assessed all data sets in two reading sessions by measuring detection accuracy with a two-alternative forced choice approach (first session) and by scoring the total number of visible object groups (second session). Dose reduction potentials based on both reading sessions were estimated. Results between FBP and ADMIRE were compared by using both paired t tests and analysis of variance tests at the 95% significance level. RESULTS During the first session, detection accuracy increased with increasing contrast, size, and dose index (diagnostic accuracy range, 50%-87%; interobserver variability, ±7%). When compared with FBP, ADMIRE improved detection accuracy by 5.2% on average across the investigated variables (P < .001). During the second session, a significantly increased number of visible objects was noted with increasing radiation dose index, section thickness, and ADMIRE strength over FBP (up to 80% more visible objects, P < .001). Radiation dose reduction potential ranged from 56% to 60% and from 4% to 80% during the two sessions, respectively. CONCLUSION Low-contrast detectability performance increased with increasing object size, object contrast, dose index, section thickness, and ADMIRE strength. Compared with FBP, ADMIRE allows a substantial radiation dose reduction while preserving low-contrast detectability. Online supplemental material is available for this article.
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Affiliation(s)
- Justin Solomon
- From the Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, 2424 Erwin Rd, Suite 302, Durham, NC 27705 (J.S., E.S.); Department of Radiology, Duke University Medical Center, Durham, NC (A.M.); and Siemens Medical Solutions USA, Malvern, Pa (J.C.R.)
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313
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Kaza RK, Platt JF, Goodsitt MM, Al-Hawary MM, Maturen KE, Wasnik AP, Pandya A. Emerging techniques for dose optimization in abdominal CT. Radiographics 2015; 34:4-17. [PMID: 24428277 DOI: 10.1148/rg.341135038] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Recent advances in computed tomographic (CT) scanning technique such as automated tube current modulation (ATCM), optimized x-ray tube voltage, and better use of iterative image reconstruction have allowed maintenance of good CT image quality with reduced radiation dose. ATCM varies the tube current during scanning to account for differences in patient attenuation, ensuring a more homogeneous image quality, although selection of the appropriate image quality parameter is essential for achieving optimal dose reduction. Reducing the x-ray tube voltage is best suited for evaluating iodinated structures, since the effective energy of the x-ray beam will be closer to the k-edge of iodine, resulting in a higher attenuation for the iodine. The optimal kilovoltage for a CT study should be chosen on the basis of imaging task and patient habitus. The aim of iterative image reconstruction is to identify factors that contribute to noise on CT images with use of statistical models of noise (statistical iterative reconstruction) and selective removal of noise to improve image quality. The degree of noise suppression achieved with statistical iterative reconstruction can be customized to minimize the effect of altered image quality on CT images. Unlike with statistical iterative reconstruction, model-based iterative reconstruction algorithms model both the statistical noise and the physical acquisition process, allowing CT to be performed with further reduction in radiation dose without an increase in image noise or loss of spatial resolution. Understanding these recently developed scanning techniques is essential for optimization of imaging protocols designed to achieve the desired image quality with a reduced dose.
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Affiliation(s)
- Ravi K Kaza
- From the Department of Radiology, University of Michigan Hospitals, 1500 E Medical Center Dr, UH B1 D 502 E, Ann Arbor, MI 48109
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314
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Reconstruction of sparse-view X-ray computed tomography using adaptive iterative algorithms. Comput Biol Med 2015; 56:97-106. [DOI: 10.1016/j.compbiomed.2014.11.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2014] [Revised: 10/28/2014] [Accepted: 11/02/2014] [Indexed: 11/19/2022]
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315
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Bicer T, Gursoy D, Kettimuthu R, De Carlo F, Agrawal G, Foster IT. Rapid Tomographic Image Reconstruction via Large-Scale Parallelization. LECTURE NOTES IN COMPUTER SCIENCE 2015. [DOI: 10.1007/978-3-662-48096-0_23] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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316
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317
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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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318
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Mayo-Smith WW, Hara AK, Mahesh M, Sahani DV, Pavlicek W. How I Do It: Managing Radiation Dose in CT. Radiology 2014; 273:657-72. [PMID: 25420167 DOI: 10.1148/radiol.14132328] [Citation(s) in RCA: 121] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- William W Mayo-Smith
- From the Department of Radiology, Warren Alpert Medical School of Brown University, Rhode Island Hospital, Providence, RI (W.W.M.); Department of Radiology, Mayo Clinic Arizona, Scottsdale, Ariz (A.K.H., W.P.); Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Md (M.M.); and Department of Abdominal Imaging/Intervention, Massachusetts General Hospital, Boston, Mass (D.V.S.)
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319
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Brix G, Lechel U, Nekolla E, Griebel J, Becker C. Radiation protection issues in dynamic contrast-enhanced (perfusion) computed tomography. Eur J Radiol 2014; 84:2347-58. [PMID: 25480677 DOI: 10.1016/j.ejrad.2014.11.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 11/11/2014] [Indexed: 11/25/2022]
Abstract
Dynamic contrast-enhanced (DCE) CT studies are increasingly used in both medical care and clinical trials to improve diagnosis and therapy management of the most common life-threatening diseases: stroke, coronary artery disease and cancer. It is thus the aim of this review to briefly summarize the current knowledge on deterministic and stochastic radiation effects relevant for patient protection, to present the essential concepts for determining radiation doses and risks associated with DCE-CT studies as well as representative results, and to discuss relevant aspects to be considered in the process of justification and optimization of these studies. For three default DCE-CT protocols implemented at a latest-generation CT system for cerebral, myocardial and cancer perfusion imaging, absorbed doses were measured by thermoluminescent dosimeters at an anthropomorphic body phantom and compared with thresholds for harmful (deterministic) tissue reactions. To characterize stochastic radiation risks of patients from these studies, life-time attributable cancer risks (LAR) were estimated using sex-, age-, and organ-specific risk models based on the hypothesis of a linear non-threshold dose-response relationship. For the brain, heart and pelvic cancer studies considered, local absorbed doses in the imaging field were about 100-190 mGy (total CTDI(vol), 200 mGy), 15-30 mGy (16 mGy) and 80-270 mGy (140 mGy), respectively. According to a recent publication of the International Commission on Radiological Protection (ICRP Publication 118, 2012), harmful tissue reactions of the cerebro- and cardiovascular systems as well as of the lenses of the eye become increasingly important at radiation doses of more than 0.5 Gy. The LARs estimated for the investigated cerebral and myocardial DCE-CT scenarios are less than 0.07% for males and 0.1% for females at an age of exposure of 40 years. For the considered tumor location and protocol, the corresponding LARs are more than 6 times as high. Stochastic radiation risks decrease substantially with age and are markedly higher for females than for males. To balance the diagnostic needs and patient protection, DCE-CT studies have to be strictly justified and carefully optimized in due consideration of the various aspects discussed in some detail in this review.
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Affiliation(s)
- Gunnar Brix
- Department of Medical and Occupational Radiation Protection, Federal Office for Radiation Protection, Ingolstädter Landstraße 1, D-85764 Oberschleissheim, Germany.
| | - Ursula Lechel
- Department of Medical and Occupational Radiation Protection, Federal Office for Radiation Protection, Ingolstädter Landstraße 1, D-85764 Oberschleissheim, Germany.
| | - Elke Nekolla
- Department of Medical and Occupational Radiation Protection, Federal Office for Radiation Protection, Ingolstädter Landstraße 1, D-85764 Oberschleissheim, Germany.
| | - Jürgen Griebel
- Department of Medical and Occupational Radiation Protection, Federal Office for Radiation Protection, Ingolstädter Landstraße 1, D-85764 Oberschleissheim, Germany.
| | - Christoph Becker
- Department of Clinical Radiology, Grosshadern Clinic, Hospital of the Ludwig-Maximilians University, Marchioninistraße 15, D-81377 Munich, Germany.
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320
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A novel weighted total difference based image reconstruction algorithm for few-view computed tomography. PLoS One 2014; 9:e109345. [PMID: 25275385 PMCID: PMC4183702 DOI: 10.1371/journal.pone.0109345] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Accepted: 09/09/2014] [Indexed: 11/19/2022] Open
Abstract
In practical applications of computed tomography (CT) imaging, due to the risk of high radiation dose imposed on the patients, it is desired that high quality CT images can be accurately reconstructed from limited projection data. While with limited projections, the images reconstructed often suffer severe artifacts and the edges of the objects are blurred. In recent years, the compressed sensing based reconstruction algorithm has attracted major attention for CT reconstruction from a limited number of projections. In this paper, to eliminate the streak artifacts and preserve the edge structure information of the object, we present a novel iterative reconstruction algorithm based on weighted total difference (WTD) minimization, and demonstrate the superior performance of this algorithm. The WTD measure enforces both the sparsity and the directional continuity in the gradient domain, while the conventional total difference (TD) measure simply enforces the gradient sparsity horizontally and vertically. To solve our WTD-based few-view CT reconstruction model, we use the soft-threshold filtering approach. Numerical experiments are performed to validate the efficiency and the feasibility of our algorithm. For a typical slice of FORBILD head phantom, using 40 projections in the experiments, our algorithm outperforms the TD-based algorithm with more than 60% gains in terms of the root-mean-square error (RMSE), normalized root mean square distance (NRMSD) and normalized mean absolute distance (NMAD) measures and with more than 10% gains in terms of the peak signal-to-noise ratio (PSNR) measure. While for the experiments of noisy projections, our algorithm outperforms the TD-based algorithm with more than 15% gains in terms of the RMSE, NRMSD and NMAD measures and with more than 4% gains in terms of the PSNR measure. The experimental results indicate that our algorithm achieves better performance in terms of suppressing streak artifacts and preserving the edge structure information of the object.
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321
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Muenzel D, Koehler T, Brown K, Žabić S, Fingerle AA, Waldt S, Bendik E, Zahel T, Schneider A, Dobritz M, Rummeny EJ, Noël PB. Validation of a low dose simulation technique for computed tomography images. PLoS One 2014; 9:e107843. [PMID: 25247422 PMCID: PMC4172631 DOI: 10.1371/journal.pone.0107843] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 08/21/2014] [Indexed: 02/02/2023] Open
Abstract
PURPOSE Evaluation of a new software tool for generation of simulated low-dose computed tomography (CT) images from an original higher dose scan. MATERIALS AND METHODS Original CT scan data (100 mAs, 80 mAs, 60 mAs, 40 mAs, 20 mAs, 10 mAs; 100 kV) of a swine were acquired (approved by the regional governmental commission for animal protection). Simulations of CT acquisition with a lower dose (simulated 10-80 mAs) were calculated using a low-dose simulation algorithm. The simulations were compared to the originals of the same dose level with regard to density values and image noise. Four radiologists assessed the realistic visual appearance of the simulated images. RESULTS Image characteristics of simulated low dose scans were similar to the originals. Mean overall discrepancy of image noise and CT values was -1.2% (range -9% to 3.2%) and -0.2% (range -8.2% to 3.2%), respectively, p>0.05. Confidence intervals of discrepancies ranged between 0.9-10.2 HU (noise) and 1.9-13.4 HU (CT values), without significant differences (p>0.05). Subjective observer evaluation of image appearance showed no visually detectable difference. CONCLUSION Simulated low dose images showed excellent agreement with the originals concerning image noise, CT density values, and subjective assessment of the visual appearance of the simulated images. An authentic low-dose simulation opens up opportunity with regard to staff education, protocol optimization and introduction of new techniques.
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Affiliation(s)
- Daniela Muenzel
- Department of Radiology, Technische Universitaet Muenchen, Munich, Germany
- * E-mail:
| | - Thomas Koehler
- Philips Technologie GmbH, Innovative Technologies, Hamburg, Germany
| | - Kevin Brown
- Philips Healthcare, Cleveland, Ohio, United States of America
| | - Stanislav Žabić
- Philips Healthcare, Cleveland, Ohio, United States of America
| | | | - Simone Waldt
- Department of Radiology, Technische Universitaet Muenchen, Munich, Germany
| | - Edgar Bendik
- Department of Radiology, Technische Universitaet Muenchen, Munich, Germany
| | - Tina Zahel
- Department of Radiology, Technische Universitaet Muenchen, Munich, Germany
| | - Armin Schneider
- MITI - Minimal-invasive Interdisciplinary therapeutic intervention research group, Technische Universitaet Muenchen, Munich, Germany
| | - Martin Dobritz
- Department of Radiology, Technische Universitaet Muenchen, Munich, Germany
| | - Ernst J. Rummeny
- Department of Radiology, Technische Universitaet Muenchen, Munich, Germany
| | - Peter B. Noël
- Department of Radiology, Technische Universitaet Muenchen, Munich, Germany
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322
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Remer EM, Herts BR, Primak A, Obuchowski NA, Greiwe A, Roesel DM, Purysko AS, Feldman MK, De S, Shah SN, Dong F, Monga M, Baker ME. Detection of Urolithiasis: Comparison of 100% Tube Exposure Images Reconstructed with Filtered Back Projection and 50% Tube Exposure Images Reconstructed with Sinogram-affirmed Iterative Reconstruction. Radiology 2014; 272:749-56. [DOI: 10.1148/radiol.14132381] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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323
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Zhang H, Ma J, Wang J, Liu Y, Lu H, Liang Z. Statistical image reconstruction for low-dose CT using nonlocal means-based regularization. Comput Med Imaging Graph 2014; 38:423-35. [PMID: 24881498 PMCID: PMC4152958 DOI: 10.1016/j.compmedimag.2014.05.002] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 03/24/2014] [Accepted: 05/02/2014] [Indexed: 11/19/2022]
Abstract
Low-dose computed tomography (CT) imaging without sacrifice of clinical tasks is desirable due to the growing concerns about excessive radiation exposure to the patients. One common strategy to achieve low-dose CT imaging is to lower the milliampere-second (mAs) setting in data scanning protocol. However, the reconstructed CT images by the conventional filtered back-projection (FBP) method from the low-mAs acquisitions may be severely degraded due to the excessive noise. Statistical image reconstruction (SIR) methods have shown potentials to significantly improve the reconstructed image quality from the low-mAs acquisitions, wherein the regularization plays a critical role and an established family of regularizations is based on the Markov random field (MRF) model. Inspired by the success of nonlocal means (NLM) in image processing applications, in this work, we propose to explore the NLM-based regularization for SIR to reconstruct low-dose CT images from low-mAs acquisitions. Experimental results with both digital and physical phantoms consistently demonstrated that SIR with the NLM-based regularization can achieve more gains than SIR with the well-known Gaussian MRF regularization or the generalized Gaussian MRF regularization and the conventional FBP method, in terms of image noise reduction and resolution preservation.
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Affiliation(s)
- Hao Zhang
- Department of Radiology, State University of New York at Stony Brook, NY 11794, USA; Department of Biomedical Engineering, State University of New York at Stony Brook, NY 11794, USA
| | - Jianhua Ma
- Department of Radiology, State University of New York at Stony Brook, NY 11794, USA; School of Biomedical Engineering, Southern Medical University, Guangdong 510515, China
| | - Jing Wang
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, TX 75390, USA
| | - Yan Liu
- Department of Radiology, State University of New York at Stony Brook, NY 11794, USA
| | - Hongbing Lu
- Department of Biomedical Engineering, Fourth Military Medical University, Shanxi 710032, China
| | - Zhengrong Liang
- Department of Radiology, State University of New York at Stony Brook, NY 11794, USA; Department of Biomedical Engineering, State University of New York at Stony Brook, NY 11794, USA.
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324
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Notohamiprodjo S, Deak Z, Meurer F, Maertz F, Mueck FG, Geyer LL, Wirth S. Image quality of iterative reconstruction in cranial CT imaging: comparison of model-based iterative reconstruction (MBIR) and adaptive statistical iterative reconstruction (ASiR). Eur Radiol 2014; 25:140-6. [DOI: 10.1007/s00330-014-3374-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 07/09/2014] [Accepted: 07/22/2014] [Indexed: 11/30/2022]
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325
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Jensen K, Martinsen ACT, Tingberg A, Aaløkken TM, Fosse E. Comparing five different iterative reconstruction algorithms for computed tomography in an ROC study. Eur Radiol 2014; 24:2989-3002. [DOI: 10.1007/s00330-014-3333-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 07/01/2014] [Accepted: 07/08/2014] [Indexed: 10/25/2022]
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326
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Koc G, Courtier JL, Phelps A, Marcovici PA, MacKenzie JD. Computed tomography depiction of small pediatric vessels with model-based iterative reconstruction. Pediatr Radiol 2014; 44:787-94. [PMID: 24531191 DOI: 10.1007/s00247-014-2899-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 12/31/2013] [Accepted: 01/23/2014] [Indexed: 12/12/2022]
Abstract
BACKGROUND Computed tomography (CT) is extremely important in characterizing blood vessel anatomy and vascular lesions in children. Recent advances in CT reconstruction technology hold promise for improved image quality and also reductions in radiation dose. This report evaluates potential improvements in image quality for the depiction of small pediatric vessels with model-based iterative reconstruction (Veo™), a technique developed to improve image quality and reduce noise. OBJECTIVE To evaluate Veo™ as an improved method when compared to adaptive statistical iterative reconstruction (ASIR™) for the depiction of small vessels on pediatric CT. MATERIALS AND METHODS Seventeen patients (mean age: 3.4 years, range: 2 days to 10.0 years; 6 girls, 11 boys) underwent contrast-enhanced CT examinations of the chest and abdomen in this HIPAA compliant and institutional review board approved study. Raw data were reconstructed into separate image datasets using Veo™ and ASIR™ algorithms (GE Medical Systems, Milwaukee, WI). Four blinded radiologists subjectively evaluated image quality. The pulmonary, hepatic, splenic and renal arteries were evaluated for the length and number of branches depicted. Datasets were compared with parametric and non-parametric statistical tests. RESULTS Readers stated a preference for Veo™ over ASIR™ images when subjectively evaluating image quality criteria for vessel definition, image noise and resolution of small anatomical structures. The mean image noise in the aorta and fat was significantly less for Veo™ vs. ASIR™ reconstructed images. Quantitative measurements of mean vessel lengths and number of branches vessels delineated were significantly different for Veo™ and ASIR™ images. Veo™ consistently showed more of the vessel anatomy: longer vessel length and more branching vessels. CONCLUSION When compared to the more established adaptive statistical iterative reconstruction algorithm, model-based iterative reconstruction appears to produce superior images for depiction of small pediatric vessels on computed tomography.
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Affiliation(s)
- Gonca Koc
- Department of Radiology and Biomedical Imaging, UCSF Benioff Children's Hospital, 505 Parnassus Ave., San Francisco, CA, 94143-0628, USA
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327
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Illies T, Säring D, Kinoshita M, Fujinaka T, Bester M, Fiehler J, Tomiyama N, Watanabe Y. Cerebral aneurysm pulsation: do iterative reconstruction methods improve measurement accuracy in vivo? AJNR Am J Neuroradiol 2014; 35:2159-63. [PMID: 24970550 DOI: 10.3174/ajnr.a4000] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Electrocardiogram-gated 4D-CTA is a promising technique allowing new insight into aneurysm pathophysiology and possibly improving risk prediction of cerebral aneurysms. Due to the extremely small pulsational excursions (<0.1 mm in diameter), exact segmentation of the aneurysms is of critical importance. In vitro examinations have shown improvement of the accuracy of vessel delineation by iterative reconstruction methods. We hypothesized that this improvement shows a measurable effect on aneurysm pulsations in vivo. MATERIALS AND METHODS Ten patients with cerebral aneurysms underwent 4D-CTA. Images were reconstructed with filtered back-projection and iterative reconstruction. The following parameters were compared between both groups: image noise, absolute aneurysm volumes, pulsatility, and sharpness of aneurysm edges. RESULTS In iterative reconstruction images, noise was significantly reduced (mean, 9.8 ± 4.0 Hounsfield units versus 8.0 ± 2.5 Hounsfield units; P = .04), but the sharpness of aneurysm edges just missed statistical significance (mean, 3.50 ± 0.49 mm versus 3.42 ± 0.49 mm; P = .06). Absolute volumes (mean, 456.1 ± 775.2 mm(3) versus 461.7 ± 789.9 mm(3); P = .31) and pulsatility (mean, 1.099 ± 0.088 mm(3) versus 1.095 ± 0.082 mm(3); P = .62) did not show a significant difference between iterative reconstruction and filtered back-projection images. CONCLUSIONS CT images reconstructed with iterative reconstruction methods show a tendency toward shorter vessel edges but do not affect absolute aneurysm volumes or pulsatility measurements in vivo.
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Affiliation(s)
- T Illies
- From the Departments of Diagnostic and Interventional Neuroradiology (T.I., M.B., J.F.)
| | - D Säring
- Medical Informatics (D.S.), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | - T Fujinaka
- Departments of Neurosurgery (M.K., T.F.)
| | - M Bester
- From the Departments of Diagnostic and Interventional Neuroradiology (T.I., M.B., J.F.)
| | - J Fiehler
- From the Departments of Diagnostic and Interventional Neuroradiology (T.I., M.B., J.F.)
| | - N Tomiyama
- Radiology (N.T., Y.W.), Osaka University Graduate School of Medicine, Osaka, Japan
| | - Y Watanabe
- Radiology (N.T., Y.W.), Osaka University Graduate School of Medicine, Osaka, Japan
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328
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Beitzke D, Nolz R, Unterhumer S, Plank C, Weber M, Schernthaner R, Schöpf V, Wolf F, Loewe C. Low-dose high-pitch CT angiography of the supraaortic arteries using sinogram-affirmed iterative reconstruction. PLoS One 2014; 9:e99832. [PMID: 24919195 PMCID: PMC4053523 DOI: 10.1371/journal.pone.0099832] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 05/19/2014] [Indexed: 11/18/2022] Open
Abstract
Objective To prospectively evaluate image quality and radiation dose using a low-dose computed tomography angiography protocol and iterative image reconstruction for high-pitch dual-source CT-angiography (DSCTA) of the supraaortic arteries. Material and Methods DSCTA was performed in 42 patients, using either 120 kVp tube voltage, 120 mAS tube current, 2.4 pitch and filtered back projection, or 100 kVp tube voltage, 100 mAs tube current, 3.2 pitch, and sinogram affirmed iterative reconstruction. Measurements of vessel attenuation, of the contrast-to-noise ratio (CNR) and the signal-to-noise ratio (SNR) were performed to objectively evaluate image quality. Two readers evaluated subjective image quality and image noise, using a four-point scale. Effective dose was used to compare the differences in radiation dose. Results Low-dose protocol application showed significantly higher vessel opacification (p = 0.013), and non-significantly higher CNR and SNR values. There was no difference in the subjective image quality and image noise reading between the protocols. Effective dose was significantly lower using the low-dose protocol (1.29±0.21 mSv vs. 2.92±0.72 mSv; p<0.001). Conclusion The combined use of reduced tube voltage, reduced tube current, and iterative reconstruction reduces radiation dose by 55.4% in high-pitch DSCTA of the supraaortic arteries without impairment of image quality.
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Affiliation(s)
- Dietrich Beitzke
- Department of Biomedical Imaging and Image-guided Therapy, Division of Cardiovascular and Interventional Radiology, Medical University Vienna, Vienna, Austria
- * E-mail:
| | - Richard Nolz
- Department of Biomedical Imaging and Image-guided Therapy, Division of Cardiovascular and Interventional Radiology, Medical University Vienna, Vienna, Austria
| | - Sylvia Unterhumer
- Department of Biomedical Imaging and Image-guided Therapy, Division of Cardiovascular and Interventional Radiology, Medical University Vienna, Vienna, Austria
| | - Christina Plank
- Department of Biomedical Imaging and Image-guided Therapy, Division of Cardiovascular and Interventional Radiology, Medical University Vienna, Vienna, Austria
| | - Michael Weber
- Department of Biomedical Imaging and Image-guided Therapy, Division of Cardiovascular and Interventional Radiology, Medical University Vienna, Vienna, Austria
| | - Rüdiger Schernthaner
- Department of Biomedical Imaging and Image-guided Therapy, Division of Cardiovascular and Interventional Radiology, Medical University Vienna, Vienna, Austria
| | - Veronika Schöpf
- Department of Biomedical Imaging and Image-guided Therapy, Division of Neuroradiology and Musculoskeletal Radiology, Medical University Vienna, Vienna, Austria
| | - Florian Wolf
- Department of Biomedical Imaging and Image-guided Therapy, Division of Cardiovascular and Interventional Radiology, Medical University Vienna, Vienna, Austria
| | - Christian Loewe
- Department of Biomedical Imaging and Image-guided Therapy, Division of Cardiovascular and Interventional Radiology, Medical University Vienna, Vienna, Austria
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329
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Ichikawa K. [Clinical application 1: properties of computed tomography images reconstructed by filtered back projection algorithm]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2014; 70:595-601. [PMID: 24953327 DOI: 10.6009/jjrt.2014_jsrt_70.6.595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
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330
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Brambilla M, De Mauri A, Lizio D, Leva L, Carriero A, Carpeggiani C, Picano E. Cumulative radiation dose estimates from medical imaging in paediatric patients with non-oncologic chronic illnesses. A systematic review. Phys Med 2014; 30:403-12. [DOI: 10.1016/j.ejmp.2013.12.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 12/23/2013] [Accepted: 12/27/2013] [Indexed: 10/25/2022] Open
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331
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Hernandez-Giron I, Calzado A, Geleijns J, Joemai RMS, Veldkamp WJH. Comparison between human and model observer performance in low-contrast detection tasks in CT images: application to images reconstructed with filtered back projection and iterative algorithms. Br J Radiol 2014; 87:20140014. [PMID: 24837275 DOI: 10.1259/bjr.20140014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
OBJECTIVE To compare low-contrast detectability (LCDet) performance between a model [non-pre-whitening matched filter with an eye filter (NPWE)] and human observers in CT images reconstructed with filtered back projection (FBP) and iterative [adaptive iterative dose reduction three-dimensional (AIDR 3D; Toshiba Medical Systems, Zoetermeer, Netherlands)] algorithms. METHODS Images of the Catphan® phantom (Phantom Laboratories, New York, NY) were acquired with Aquilion ONE™ 320-detector row CT (Toshiba Medical Systems, Tokyo, Japan) at five tube current levels (20-500 mA range) and reconstructed with FBP and AIDR 3D. Samples containing either low-contrast objects (diameters, 2-15 mm) or background were extracted and analysed by the NPWE model and four human observers in a two-alternative forced choice detection task study. Proportion correct (PC) values were obtained for each analysed object and used to compare human and model observer performances. An efficiency factor (η) was calculated to normalize NPWE to human results. RESULTS Human and NPWE model PC values (normalized by the efficiency, η = 0.44) were highly correlated for the whole dose range. The Pearson's product-moment correlation coefficients (95% confidence interval) between human and NPWE were 0.984 (0.972-0.991) for AIDR 3D and 0.984 (0.971-0.991) for FBP, respectively. Bland-Altman plots based on PC results showed excellent agreement between human and NPWE [mean absolute difference 0.5 ± 0.4%; range of differences (-4.7%, 5.6%)]. CONCLUSION The NPWE model observer can predict human performance in LCDet tasks in phantom CT images reconstructed with FBP and AIDR 3D algorithms at different dose levels. ADVANCES IN KNOWLEDGE Quantitative assessment of LCDet in CT can accurately be performed using software based on a model observer.
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332
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Bian J, Yang K, Boone JM, Han X, Sidky EY, Pan X. Investigation of iterative image reconstruction in low-dose breast CT. Phys Med Biol 2014; 59:2659-85. [PMID: 24786683 DOI: 10.1088/0031-9155/59/11/2659] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
There is interest in developing computed tomography (CT) dedicated to breast-cancer imaging. Because breast tissues are radiation-sensitive, the total radiation exposure in a breast-CT scan is kept low, often comparable to a typical two-view mammography exam, thus resulting in a challenging low-dose-data-reconstruction problem. In recent years, evidence has been found that suggests that iterative reconstruction may yield images of improved quality from low-dose data. In this work, based upon the constrained image total-variation minimization program and its numerical solver, i.e., the adaptive steepest descent-projection onto the convex set (ASD-POCS), we investigate and evaluate iterative image reconstructions from low-dose breast-CT data of patients, with a focus on identifying and determining key reconstruction parameters, devising surrogate utility metrics for characterizing reconstruction quality, and tailoring the program and ASD-POCS to the specific reconstruction task under consideration. The ASD-POCS reconstructions appear to outperform the corresponding clinical FDK reconstructions, in terms of subjective visualization and surrogate utility metrics.
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Affiliation(s)
- Junguo Bian
- Department of Radiology, Harvard Medical School and Massachusetts General Hospital, Boston, MA 02114, USA
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333
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334
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Lee S, Kim HJ. Noise properties of reconstructed images in a kilo-voltage on-board imaging system with iterative reconstruction techniques: A phantom study. Phys Med 2014; 30:365-73. [DOI: 10.1016/j.ejmp.2013.11.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Revised: 11/18/2013] [Accepted: 11/21/2013] [Indexed: 12/01/2022] Open
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335
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Berta L, Mascaro L, Feroldi P, Maroldi R. Optimisation of an MDCT abdominal protocol: Image quality assessment of standard vs. iterative reconstructions. Phys Med 2014; 30:271-9. [DOI: 10.1016/j.ejmp.2013.07.126] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 07/04/2013] [Accepted: 07/15/2013] [Indexed: 01/01/2023] Open
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Hoxworth JM, Lal D, Fletcher GP, Patel AC, He M, Paden RG, Hara AK. Radiation dose reduction in paranasal sinus CT using model-based iterative reconstruction. AJNR Am J Neuroradiol 2014; 35:644-9. [PMID: 24113467 DOI: 10.3174/ajnr.a3749] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE CT performed with Veo model-based iterative reconstruction has shown the potential for radiation-dose reduction. This study sought to determine whether Veo could reduce noise and improve the image quality of low-dose sinus CT. MATERIALS AND METHODS Twenty patients consented to participate and underwent low- and standard-dose sinus CT on the same day. Standard-dose CT was created with filtered back-projection (120 kV[peak], 210 mA, 0.4-second rotation, and 0.531 pitch). For low-dose CT, mA was decreased to 20 (the remaining parameters were unchanged), and images were generated with filtered back-projection and Veo. Standard- and low-dose datasets were reconstructed by using bone and soft-tissue algorithms, while the low-dose Veo reconstruction only had a standard kernel. Two blinded neuroradiologists independently evaluated the image quality of multiple osseous and soft-tissue craniofacial structures. Image noise was measured by using multiple regions of interest. RESULTS Eight women and 12 men (mean age, 63.3 years) participated. Volume CT dose indices were 2.9 mGy (low dose) and 31.6 mGy (standard dose), and mean dose-length products were 37.4 mGy-cm (low dose) and 406.1 mGy-cm (standard dose). Of all the imaging series, low-dose Veo demonstrated the least noise (P < .001). Compared with filtered back-projection low-dose CT using soft-tissue and bone algorithms, Veo had the best soft-tissue image quality but the poorest bone image quality (P < .001). CONCLUSIONS Veo significantly reduces noise in low-dose sinus CT. Although this reduction improves soft-tissue evaluation, thin bone becomes less distinct.
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Affiliation(s)
- J M Hoxworth
- From the Departments of Radiology (J.M.H., G.P.F., A.C.P., R.G.P, A.K.H.)
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337
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Funama Y, Taguchi K, Utsunomiya D, Oda S, Katahira K, Tokuyasu S, Yamashita Y. Image quality assessment of an iterative reconstruction algorithm applied to abdominal CT imaging. Phys Med 2014; 30:527-34. [PMID: 24662097 DOI: 10.1016/j.ejmp.2014.02.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 02/19/2014] [Accepted: 02/27/2014] [Indexed: 10/25/2022] Open
Abstract
PURPOSE To compare the noise and accuracy on images of the whole porcine liver acquired with iterative reconstruction (IMR, Philips Healthcare, Cleveland, OH, USA) and filtered back projection (FBP) methods. MATERIALS AND METHODS We used non-enhanced porcine liver to simulate the human liver and acquired it 100 times to obtain the average FBP value as the ground-truth. The mean and the standard deviation ("inter-scan SD") of the pixel values on the 100 image acquisitions were calculated for FBP and for three levels of IMR (L1, L2, and L3). We also calculated the noise power spectrum (NPS) and the normalized NPS for the 100 image acquisitions. RESULTS The spatial SD for the porcine liver parenchyma on these slices was 9.92, 4.37, 3.63, and 2.30 Hounsfield units with FBP, IMR-L1, IMR-L2, and IMR-L3, respectively. The detectability of small faint features was better on single IMR than single FBP images. The inter-scan SD value for IMR-L3 images was 53% larger at the liver edges than at the liver parenchyma; it was only 10% larger on FBP images. Assessment of the normalized NPS showed that the noise on IMR images was comprised primarily of low-frequency components. CONCLUSION IMR images yield the same structure informations as FBP images and image accuracy is maintained. On level 3 IMR images the image noise is more strongly suppressed than on IMR images of the other levels and on FBP images.
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Affiliation(s)
- Yoshinori Funama
- Department of Medical Physics, Faculty of Life Sciences, Kumamoto University, 4-24-1 Kuhonji, Kumamoto 862-0976, Japan.
| | - Katsuyuki Taguchi
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, USA
| | - Daisuke Utsunomiya
- Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University, Japan
| | - Seitaro Oda
- Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University, Japan
| | | | | | - Yasuyuki Yamashita
- Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University, Japan
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338
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CT exposure in adult and paediatric patients: a review of the mechanisms of damage, relative dose and consequent possible risks. Radiol Med 2014; 119:803-10. [PMID: 24599754 DOI: 10.1007/s11547-014-0393-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 07/30/2013] [Indexed: 01/21/2023]
Abstract
An increase has been observed not only in the absolute number of CT examinations but also in the length of coverage and number of scanning phases, with the result that exposure to ionising radiation from CT is becoming an increasingly serious problem. The extent of the problem is not entirely known and cannot be adequately addressed without proper knowledge of all the phases that leads to the effective dose calculation. In light of the growing awareness of the issue of ionising radiation dose and the possible risk for the individual and the population, there is a need for radiologists, medical physicists and radiographers to play an active role in dose management. In this review, the authors try to delineate the problem in a consequential and multifaceted way: radiation-patient interaction, possible mechanisms of damage, main CT dose units, risk and its quantification in the population, with the aim of optimising the acquisition dose without diagnostic drawbacks. For an "up-to-date" use of CT, radiologists must know the dose concerns for the single patient and population, and use the CT apparatus with the best dose care; substitute CT with other diagnostic techniques when possible, especially in children; reduce the number/extension of scans and phases, and the dose in single scans and single examinations.
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339
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Makeev A, Glick SJ. Investigation of statistical iterative reconstruction for dedicated breast CT. Med Phys 2014; 40:081904. [PMID: 23927318 DOI: 10.1118/1.4811328] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
PURPOSE Dedicated breast CT has great potential for improving the detection and diagnosis of breast cancer. Statistical iterative reconstruction (SIR) in dedicated breast CT is a promising alternative to traditional filtered backprojection (FBP). One of the difficulties in using SIR is the presence of free parameters in the algorithm that control the appearance of the resulting image. These parameters require tuning in order to achieve high quality reconstructions. In this study, the authors investigated the penalized maximum likelihood (PML) method with two commonly used types of roughness penalty functions: hyperbolic potential and anisotropic total variation (TV) norm. Reconstructed images were compared with images obtained using standard FBP. Optimal parameters for PML with the hyperbolic prior are reported for the task of detecting microcalcifications embedded in breast tissue. METHODS Computer simulations were used to acquire projections in a half-cone beam geometry. The modeled setup describes a realistic breast CT benchtop system, with an x-ray spectra produced by a point source and an a-Si, CsI:Tl flat-panel detector. A voxelized anthropomorphic breast phantom with 280 μm microcalcification spheres embedded in it was used to model attenuation properties of the uncompressed woman's breast in a pendant position. The reconstruction of 3D images was performed using the separable paraboloidal surrogates algorithm with ordered subsets. Task performance was assessed with the ideal observer detectability index to determine optimal PML parameters. RESULTS The authors' findings suggest that there is a preferred range of values of the roughness penalty weight and the edge preservation threshold in the penalized objective function with the hyperbolic potential, which resulted in low noise images with high contrast microcalcifications preserved. In terms of numerical observer detectability index, the PML method with optimal parameters yielded substantially improved performance (by a factor of greater than 10) compared to FBP. The hyperbolic prior was also observed to be superior to the TV norm. A few of the best-performing parameter pairs for the PML method also demonstrated superior performance for various radiation doses. In fact, using PML with certain parameter values results in better images, acquired using 2 mGy dose, than FBP-reconstructed images acquired using 6 mGy dose. CONCLUSIONS A range of optimal free parameters for the PML algorithm with hyperbolic and TV norm-based potentials is presented for the microcalcification detection task, in dedicated breast CT. The reported values can be used as starting values of the free parameters, when SIR techniques are used for image reconstruction. Significant improvement in image quality can be achieved by using PML with optimal combination of parameters, as compared to FBP. Importantly, these results suggest improved detection of microcalcifications can be obtained by using PML with lower radiation dose to the patient, than using FBP with higher dose.
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Affiliation(s)
- Andrey Makeev
- UMass Medical School, 55 Lake Avenue North, Worcester, Massachusetts 01655, USA
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Evaluation of Low-Dose CT Angiography With Model-Based Iterative Reconstruction After Endovascular Aneurysm Repair of a Thoracic or Abdominal Aortic Aneurysm. AJR Am J Roentgenol 2014; 202:648-55. [DOI: 10.2214/ajr.13.11286] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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341
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Löve A, Siemund R, Höglund P, Van Westen D, Stenberg L, Petersen C, Björkman-Burtscher IM. Hybrid iterative reconstruction algorithm in brain CT: a radiation dose reduction and image quality assessment study. Acta Radiol 2014; 55:208-17. [PMID: 23897306 DOI: 10.1177/0284185113494980] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Iterative reconstruction (IR) algorithms improve image quality and allow for radiation dose reduction in CT. Dose reduction is particularly challenging in brain CT where good low-contrast resolution is essential. Ideally, evaluation of image quality combines objective measurements and subjective assessment of clinically relevant quality criteria. Subjective assessment is associated with various pitfalls and biases. PURPOSE To evaluate the potential of the hybrid IR algorithm iDOSE(4) to preserve image quality in phantom and clinical brain CT acquired with 30% reduced radiation dose, and to discuss the image quality assessment methods. MATERIAL AND METHODS Forty patients underwent two consecutive brain CTs with normal radiation dose (ND) and 30% reduced dose (RD). Both ND and RD were reconstructed with FBP. In addition the reduced dose CTs were reconstructed with two levels of IR (ID2, ID4). Three image quality criteria (grey-white-matter discrimination, basal ganglia delineation, general image quality) were graded and ranked by six neuroradiologists. Noise levels and contrast-to-noise ratios (CNR) were measured in clinical data. Noise, signal-to-noise ratio (SNR), spatial resolution, and noise-power spectrum (NPS) were also assessed in a phantom. RESULTS Subjective image quality was considered adequate for clinical use for all reconstructions, graded good or excellent in 93% of cases for ND, 83% for ID4, 79% for ID2, and 67% for RD. For all quality parameters, ID4 and ID2 were graded better than RD (P < 0.0055 and P < 0.035), but worse than ND (P < 0.001). In clinical images, objective measurements showed lower noise and significantly higher CNR in ID4 compared with ND and RD (P < 0.001). CNR was similar for ID2 and ND. In the phantom, IR reduced noise while maintaining spatial resolution and NPS. CONCLUSION The IR algorithm improves image quality of reduced dose CTs and consistently delivers sufficient image quality for clinical purposes. Pitfalls related to subjective assessment can be addressed with careful study design.
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Affiliation(s)
- Askell Löve
- Department of Neuroradiology, Skåne University Hospital, Lund University, Lund, Sweden
| | - Roger Siemund
- Department of Neuroradiology, Skåne University Hospital, Lund University, Lund, Sweden
| | - Peter Höglund
- Competence Centre for Clinical Research, Skåne University Hospital, Lund University, Lund, Sweden
| | - Danielle Van Westen
- Department of Neuroradiology, Skåne University Hospital, Lund University, Lund, Sweden
| | - Lars Stenberg
- Department of Neuroradiology, Skåne University Hospital, Lund University, Lund, Sweden
| | - Cecilia Petersen
- Department of Neuroradiology, Skåne University Hospital, Lund University, Lund, Sweden
| | - Isabella M Björkman-Burtscher
- Department of Neuroradiology, Skåne University Hospital, Lund University, Lund, Sweden
- Lund University Bioimaging Centre, Lund University, Lund, Sweden
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Ploussi A, Alexopoulou E, Economopoulos N, Argentos SI, Tsitsia V, Arapakis I, Kordolaimi S, Seimenis I, Efstathopoulos EP. Patient radiation exposure and image quality evaluation with the use of iDose4 iterative reconstruction algorithm in chest-abdomen-pelvis CT examinations. RADIATION PROTECTION DOSIMETRY 2014; 158:399-405. [PMID: 24107575 DOI: 10.1093/rpd/nct242] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The aim of this study is to evaluate the effect of iDose(4) iterative reconstruction algorithm on radiation dose and imaging quality at chest-abdomen-pelvis (CAP) CT examinations. Seventeen patients were considered; all patients had a previous CT scan with the standard filter back-projection (FBP) protocol and a follow-up scan with the iDose(4) protocol at the same scanner. Image noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were objectively calculated. Two radiologists evaluated noise, sharpness, contrast, diagnostic confidence and artefacts. Radiation exposure quantities were calculated. iDose(4) resulted in 46 % dose reduction combined with significantly lower noise and higher SNR and CNR compared with FBP. iDose(4) images had significantly lower subjective image noise and enhanced sharpness and contrast. Diagnostic confidence was high and image artefacts were minor for both algorithms. iDose(4) provides great potential for reducing patient radiation burden while improving imaging quality in CAP CT examinations.
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Affiliation(s)
- Agapi Ploussi
- Second Department of Radiology, Medical School, National and Kapodistrian University of Athens, Rimini 1, Athens 12462, Greece
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Spears JR, Schoepf UJ, Henzler T, Joshi G, Moscariello A, Vliegenthart R, Cho YJ, Apfaltrer P, Rowe G, Weininger M, Ebersberger U. Comparison of the effect of iterative reconstruction versus filtered back projection on cardiac CT postprocessing. Acad Radiol 2014; 21:318-24. [PMID: 24360635 DOI: 10.1016/j.acra.2013.11.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 11/06/2013] [Accepted: 11/06/2013] [Indexed: 01/22/2023]
Abstract
RATIONALE AND OBJECTIVES To investigate the impact of iterative reconstruction in image space (IRIS) on image noise, image quality (IQ), and postprocessing at coronary computed tomography angiography (cCTA) compared to traditional filtered back-projection (FBP). MATERIALS AND METHODS The cCTA results of 50 patients (26 men; 58 ± 15 years, body mass index 31.5 ± 6.7 kg/m²) were investigated using a second-generation dual-source computed tomography system. Scan data were reconstructed with the use of IRIS and FBP algorithms. Two radiologists independently evaluated the reconstructions using automated coronary tree analysis software. Image noise was measured and IQ was rated on a 5-point Likert scale. The number of manual corrections after automated vessel segmentation, the time required to complete segmentation, and the number of missed segments were assessed in both IRIS and FBP reconstructions. Results were compared using paired t-test. RESULTS IRIS significantly reduced image noise compared to FBP (23.3 ± 8.8 vs. 33.5 ± 13.5 Hounsfield units, P < .001). Subjective IQ improved with IRIS (IRIS 3.2 ± 1.0 vs. FBP 3.0 ± 1.0, P < .05). IRIS decreased the time needed for coronary segmentation from 111.9 ± 40.5 seconds to 95.2 ± 38.2 seconds with FBP (P < .01) and required fewer manual corrections (5.7 ± 3.0 vs. 6.8 ± 3.6, P < .01). The number of missed vessel segments was not significantly different (3.6 ± 1.8 vs. 3.8 ± 1.9, P > .05) between IRIS and FBP, respectively. CONCLUSIONS During cCTA postprocessing, IRIS significantly decreases the time and the number of manual corrections for a complete coronary segmentation compared to FBP. This effect is likely attributable to suppression of image noise by IRIS, which improves the performance of automated vessel segmentation and positively impacts cCTA analysis.
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Affiliation(s)
- J Reid Spears
- Heart and Vascular Center, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC, 29425-2260
| | - U Joseph Schoepf
- Heart and Vascular Center, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC, 29425-2260.
| | - Thomas Henzler
- Heart and Vascular Center, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC, 29425-2260; Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Gayatri Joshi
- Heart and Vascular Center, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC, 29425-2260
| | - Antonio Moscariello
- Heart and Vascular Center, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC, 29425-2260; Department of Bioimaging and Radiological Sciences, Catholic University of the Sacred Heart, "A. Gemelli" Hospital, Rome, Italy
| | - Rozemarijn Vliegenthart
- Heart and Vascular Center, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC, 29425-2260; Department of Radiology, Center for Medical Imaging - North East Netherlands, University of Groningen/University Medical Center Groningen, Groningen, The Netherlands
| | - Young Jun Cho
- Heart and Vascular Center, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC, 29425-2260; Department of Radiology, Konyang University College of Medicine, Daejeon, Republic of Korea
| | - Paul Apfaltrer
- Heart and Vascular Center, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC, 29425-2260; Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Garrett Rowe
- Heart and Vascular Center, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC, 29425-2260
| | - Markus Weininger
- Heart and Vascular Center, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC, 29425-2260
| | - Ullrich Ebersberger
- Heart and Vascular Center, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC, 29425-2260; Department of Cardiology and Intensive Care Medicine, Heart Center Munich-Bogenhausen, Munich, Germany
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Haubenreisser H, Fink C, Nance JW, Sedlmair M, Schmidt B, Schoenberg SO, Henzler T. Feasibility of slice width reduction for spiral cranial computed tomography using iterative image reconstruction. Eur J Radiol 2014; 83:964-969. [PMID: 24673978 DOI: 10.1016/j.ejrad.2014.01.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 01/28/2014] [Accepted: 01/30/2014] [Indexed: 11/15/2022]
Abstract
PURPOSE To prospectively compare image quality of cranial computed tomography (CCT) examinations with varying slice widths using traditional filtered back projection (FBP) versus sinogram-affirmed iterative image reconstruction (SAFIRE). MATERIALS AND METHODS 29 consecutive patients (14 men, mean age: 72 ± 17 years) referred for a total of 40 CCT studies were prospectively included. Each CCT raw data set was reconstructed with FBP and SAFIRE at 5 slice widths (1-5mm; 1mm increments). Objective image quality was assessed in three predefined regions of the brain (white matter, thalamus, cerebellum) using identical regions of interest (ROIs). Subjective image quality was assessed by 2 experienced radiologists. Objective and subjective image quality parameters were statistically compared between FBP and SAFIRE reconstructions. RESULTS SAFIRE reconstructions resulted in mean noise reductions of 43.8% in the white matter, 45.6% in the thalamus and 42.0% in the cerebellum (p<0.01) compared to FBP on non contrast-enhanced 1mm slice width images. Corresponding mean noise reductions on 1mm contrast-enhanced studies were 45.7%, 47.3%, and 45.0% in the white matter, thalamus, and cerebellum, respectively (p<0.01). There was no significant difference in mean attenuation of any region or slice width between the two reconstruction methods (all p>0.05). Subjective image quality of IR images was mostly rated higher than that of the FBP images. CONCLUSION Compared to FBP, SAFIRE provides significant reductions in image noise while increasing subjective image in CCT, particularly when thinner slices are used. Therefore, SAFIRE may allow utilization of thinner slices in CCT, potentially reducing partial volume effects and improving diagnostic accuracy.
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Affiliation(s)
- Holger Haubenreisser
- Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany
| | - Christian Fink
- Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany
| | - John W Nance
- Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany
| | | | | | - Stefan O Schoenberg
- Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany
| | - Thomas Henzler
- Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany.
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Schindler A, Vliegenthart R, Schoepf UJ, Blanke P, Ebersberger U, Cho YJ, Allmendinger T, Vogt S, Raupach R, Fink C, Saam T, Bamberg F, Nikolaou K, Apfaltrer P. Iterative Image Reconstruction Techniques for CT Coronary Artery Calcium Quantification: Comparison with Traditional Filtered Back Projection in Vitro and in Vivo. Radiology 2014; 270:387-93. [DOI: 10.1148/radiol.13130233] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Optimization of reduced-dose MDCT of thoracic aorta using iterative reconstruction. J Comput Assist Tomogr 2014; 38:72-6. [PMID: 24424557 DOI: 10.1097/rct.0b013e3182a213cd] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To evaluate the contribution of iterative reconstruction on image quality of reduced-dose multidetector computed tomography of the thoracic aorta. METHODS A torso phantom was scanned using two tube potentials (80 and 120 kVp) and five different tube currents (110, 75, 40, 20, and 10 mAs). All images were reconstructed with both filtered back projection (FBP) and iterative reconstruction. Aortic attenuation, image noise within the thoracic aorta, signal-to-noise ratio, and sharpness of the aortic wall were quantified in the phantom for the two reconstruction algorithms. Data were analyzed using paired t test. A value of P < 0.05 was considered significant. RESULTS The aortic attenuation was similar for FBP and iterative reconstruction (P > 0.05). Image noise level was lower (P < 0.0001), and image sharpness was higher (P = 0.046) with iterative reconstruction. Signal-to-noise ratios were higher with iterative reconstruction compared with those with FBP (P < 0.0001). Signal-to-noise ratio at 80 kVp with iterative reconstruction (9.8 ± 4.4) was similar to the signal-to-noise ratio at 120 kVp with FBP (8.4 ± 3.3) (P = 0.196). CONCLUSIONS Less image noise and higher image sharpness may be achieved with iterative reconstruction in reduced-dose multidetector computed tomography of the thoracic aorta.
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Renker M, Geyer LL, Krazinski AW, Silverman JR, Ebersberger U, Schoepf UJ. Iterative image reconstruction: a realistic dose-saving method in cardiac CT imaging? Expert Rev Cardiovasc Ther 2014; 11:403-9. [DOI: 10.1586/erc.12.178] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Initial Performance Evaluation of Iterative Model Reconstruction in Abdominal Computed Tomography. J Comput Assist Tomogr 2014; 38:408-14. [DOI: 10.1097/rct.0000000000000062] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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