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Xing Y, Zhao Y, Guo N, Pan CX, Azati G, Wang YW, Liu WY. Effect of a Novel Intracycle Motion Correction Algorithm on Dual-Energy Spectral Coronary CT Angiography: A Study with Pulsating Coronary Artery Phantom at High Heart Rates. Korean J Radiol 2017; 18:881-887. [PMID: 29089820 PMCID: PMC5639153 DOI: 10.3348/kjr.2017.18.6.881] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 05/02/2017] [Indexed: 02/02/2023] Open
Abstract
Objective Using a pulsating coronary artery phantom at high heart rate settings, we investigated the efficacy of a motion correction algorithm (MCA) to improve the image quality in dual-energy spectral coronary CT angiography (CCTA). Materials and Methods Coronary flow phantoms were scanned at heart rates of 60–100 beats/min at 10-beats/min increments, using dual-energy spectral CT mode. Virtual monochromatic images were reconstructed from 50 to 90 keV at 10-keV increments. Two blinded observers assessed image quality using a 4-point Likert Scale (1 = non-diagnostic, 4 = excellent) and the fraction of interpretable segments using MCA versus conventional algorithm (CA). Comparison of variables was performed with the Wilcoxon rank sum test and McNemar test. Results At heart rates of 70, 80, 90, and 100 beats/min, images with MCA were rated as higher image scores compared to those with CA on monochromatic levels of 50, 60, and 70 keV (each p < 0.05). Meanwhile, at a heart rate of 90 beats/min, image interpretability was improved by MCA at a monochromatic level of 60 keV (p < 0.05) and 70 keV (p < 0.05). At a heart rate of 100 beats/min, image interpretability was improved by MCA at monochromatic levels of 50 keV (from 69.4% to 86.1%, p < 0.05), 60 keV (from 55.6% to 83.3%, p < 0.05) and 70 keV (from 33.3% to 69.3%, p < 0.05). Conclusion Low-keV monochromatic images combined with MCA improves image quality and image interpretability in CCTAs at high heart rates.
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Affiliation(s)
- Yan Xing
- Imaging Center, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang 830011, China
| | - Yuan Zhao
- Imaging Center, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang 830011, China
| | - Ning Guo
- CT Imaging Research Center, GE Healthcare, Beijing 100176, China
| | - Cun-Xue Pan
- Imaging Center, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang 830011, China
| | - Gulina Azati
- Imaging Center, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang 830011, China
| | - Yan-Wei Wang
- Imaging Center, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang 830011, China
| | - Wen-Ya Liu
- Imaging Center, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang 830011, China
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Kalisz K, Buethe J, Saboo SS, Abbara S, Halliburton S, Rajiah P. Artifacts at Cardiac CT: Physics and Solutions. Radiographics 2016; 36:2064-2083. [PMID: 27768543 DOI: 10.1148/rg.2016160079] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Computed tomography is vulnerable to a wide variety of artifacts, including patient- and technique-specific artifacts, some of which are unique to imaging of the heart. Motion is the most common source of artifacts and can be caused by patient, cardiac, or respiratory motion. Cardiac motion artifacts can be reduced by decreasing the heart rate and variability and the duration of data acquisition; adjusting the placement of the data window within a cardiac cycle; performing single-heartbeat scanning; and using multisegment reconstruction, motion-correction algorithms, and electrocardiographic editing. Respiratory motion artifacts can be minimized with proper breath holding and shortened scan duration. Partial volume averaging is caused by the averaging of attenuation values from all tissue contained within a voxel and can be reduced by improving the spatial resolution, using a higher x-ray energy, or displaying images with a wider window width. Beam-hardening artifacts are caused by the polyenergetic nature of the x-ray beam and can be reduced by using x-ray filtration, applying higher-energy x-rays, altering patient position, modifying contrast material protocols, and applying certain reconstruction algorithms. Metal artifacts are complex and have multiple causes, including x-ray scatter, underpenetration, motion, and attenuation values that exceed the typical dynamic range of Hounsfield units. Quantum mottle or noise is caused by insufficient penetration of tissue and can be improved by increasing the tube current or peak tube potential, reconstructing thicker sections, increasing the rotation time, using appropriate patient positioning, and applying iterative reconstruction algorithms. ©RSNA, 2016.
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Affiliation(s)
- Kevin Kalisz
- From the Department of Radiology, University Hospitals Cleveland Medical Center, Cleveland, Ohio (K.K., J.B.); Department of Radiology, Cardiothoracic Imaging, UT Southwestern Medical Center, E6.120 B, Mail Code 9316, 5323 Harry Hines Blvd, Dallas, TX 75390-8896 (S.S.S., S.A., P.R.); and Philips Healthcare, Cleveland, Ohio (S.H.)
| | - Ji Buethe
- From the Department of Radiology, University Hospitals Cleveland Medical Center, Cleveland, Ohio (K.K., J.B.); Department of Radiology, Cardiothoracic Imaging, UT Southwestern Medical Center, E6.120 B, Mail Code 9316, 5323 Harry Hines Blvd, Dallas, TX 75390-8896 (S.S.S., S.A., P.R.); and Philips Healthcare, Cleveland, Ohio (S.H.)
| | - Sachin S Saboo
- From the Department of Radiology, University Hospitals Cleveland Medical Center, Cleveland, Ohio (K.K., J.B.); Department of Radiology, Cardiothoracic Imaging, UT Southwestern Medical Center, E6.120 B, Mail Code 9316, 5323 Harry Hines Blvd, Dallas, TX 75390-8896 (S.S.S., S.A., P.R.); and Philips Healthcare, Cleveland, Ohio (S.H.)
| | - Suhny Abbara
- From the Department of Radiology, University Hospitals Cleveland Medical Center, Cleveland, Ohio (K.K., J.B.); Department of Radiology, Cardiothoracic Imaging, UT Southwestern Medical Center, E6.120 B, Mail Code 9316, 5323 Harry Hines Blvd, Dallas, TX 75390-8896 (S.S.S., S.A., P.R.); and Philips Healthcare, Cleveland, Ohio (S.H.)
| | - Sandra Halliburton
- From the Department of Radiology, University Hospitals Cleveland Medical Center, Cleveland, Ohio (K.K., J.B.); Department of Radiology, Cardiothoracic Imaging, UT Southwestern Medical Center, E6.120 B, Mail Code 9316, 5323 Harry Hines Blvd, Dallas, TX 75390-8896 (S.S.S., S.A., P.R.); and Philips Healthcare, Cleveland, Ohio (S.H.)
| | - Prabhakar Rajiah
- From the Department of Radiology, University Hospitals Cleveland Medical Center, Cleveland, Ohio (K.K., J.B.); Department of Radiology, Cardiothoracic Imaging, UT Southwestern Medical Center, E6.120 B, Mail Code 9316, 5323 Harry Hines Blvd, Dallas, TX 75390-8896 (S.S.S., S.A., P.R.); and Philips Healthcare, Cleveland, Ohio (S.H.)
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Abstract
As laparoscopic surgery is replacing open surgery, similarly computed tomography angiography is replacing invasive conventional cardiac angiography. In the last century, marvelous efforts in research have improved strategies for cure, diagnosis and prevention of fatal human diseases; however, coronary artery disease, as the most prevalent cause of mortality and morbidity in the world, has remained a great challenge. Due to advancements in technology and research, it has become more simple and robust to diagnose and treat coronary artery disease (CAD) with minimal or no intervention, promising to not only diagnosis at an early stage but potential prevention altogether. While most with obvious CAD can be diagnosed easily and quickly with ECG, those identified as 'low risk' require more extensive testing to diagnose or rule out CAD. For example in emergency departments, low-risk patients with chest pain are diagnosed solely depending on history, ECG and blood testing for biomarkers. This approach has resulted in either delayed or miss-diagnosis of Acute coronary syndrome. To prevent this, many emergency departments now use protocols for low-risk heart patients that include cardiac stress tests and/or CT heart imaging. This review provides an overview of the current literature on the value of Computed tomography angiography and discusses how prognostic information obtained with Computed tomography angiography can be used to further integrate the technique into clinical practice.
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Affiliation(s)
- Muhammad A Latif
- St. John Cardiovascular Research Center, Los Angeles Biomedical Research Institute, Torrance, CA, USA
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Adaptive iterative dose reduction using 3D processing for reduced- and low-dose pulmonary CT: comparison with standard-dose CT for image noise reduction and radiological findings. AJR Am J Roentgenol 2012; 199:W477-85. [PMID: 22997397 DOI: 10.2214/ajr.11.8275] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The purpose of this study was to determine the utility of adaptive iterative dose reduction using 3D processing (AIDR 3D) for image noise reduction and assessment of radiologic findings obtained with reduced- and low-dose chest CT in patients with various pulmonary diseases. SUBJECTS AND METHODS Chest CT examinations at three different tube current settings and using 16- and 64-MDCT scanners were performed for 37 patients. Standard-dose (150 mAs) data were reconstructed as thin-section CT without AIDR 3D, and low-dose (25 mAs) and reduced-dose (50 mAs) data were reconstructed as thin-section CT without and with AIDR 3D. To compare image quality, image noises at all CT doses were quantitatively assessed by region of interest measurements. For comparison of radiologic finding assessments, likelihoods of occurrence of emphysema, ground-glass opacity, reticular opacity, bronchiectasis, honeycomb pattern, and nodules were evaluated on a 5-point scale. Then, image noise and agreements of radiologic findings between standard-dose CT and others were statistically evaluated. RESULTS The image quality scores of reduced- and low-dose CT without AIDR 3D were significantly lower than those of both protocols with AIDR 3D and standard-dose CT (p<0.05). All intermethod agreements for emphysema, ground-glass opacity, bronchiectasis, honeycomb pattern, and nodules, except for those observed on low-dose CT without AIDR 3D, were almost perfect (κ>0.81). CONCLUSION AIDR 3D is useful for image noise reduction and assessment of radiologic findings obtained with reduced- and low-dose CT for patients with various pulmonary diseases.
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A systematic approach for analysis, interpretation, and reporting of coronary CTA studies. Insights Imaging 2012; 3:215-28. [PMID: 22696084 PMCID: PMC3369123 DOI: 10.1007/s13244-012-0167-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 01/31/2012] [Accepted: 03/19/2012] [Indexed: 11/11/2022] Open
Abstract
Over the past years, the number of coronary computed tomography angiography (CTA) studies performed worldwide has been steadily increasing. Performing a coronary CTA study with appropriate protocols tailored to the individual patient and clinical question is mandatory to obtain an image quality that is diagnostic for the study purpose. This process can be considered the primary mainstay of each coronary CTA study. The secondary mainstay is represented by the correct analysis and interpretation of the acquired data, as well as reporting of the pertinent imaging findings to the referring physician. The latter process requires knowledge of the advantages and disadvantages of various post-processing methods. In addition, a standardized approach can be helpful to avoid false-positive and false-negative findings regarding the presence or absence of coronary artery disease. By implementing various radiation dose reduction techniques, care needs to be taken to keep the radiation dose of coronary CTA as low as reasonably achievable while maintaining the diagnostic capacity of the examination. This review describes a practical approach to the analysis and interpretation of coronary CTA data, including the standardized reporting of the relevant imaging findings to the referring physicians.
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Abstract
PURPOSE OF REVIEW Significant limitations exist for traditional noninvasive cardiac imaging with regard to equivocal or indeterminate findings that result in repetitive testing or unnecessary referral to invasive coronary angiography (ICA). Recent hardware and software advances in multislice computed tomography angiography have achieved high spatial and temporal resolution to allow accurate noninvasive assessment of coronary arteries. This poses a paradigm shift in management of patients with suspected coronary artery disease (CAD). RECENT FINDINGS Multicenter studies showed that coronary computed tomography angiography (CCTA) has a very high diagnostic accuracy, and, in particular, a very high negative predictive value (>98%) in detecting coronary stenosis when compared with ICA. In addition to its diagnostic ability, recent evidence-based outcome data have also validated the value of CCTA in predicting cardiac events. Absence of CAD on CCTA conveys excellent prognosis, whereas increasing disease severity and extent are associated with worsening outcome. Furthermore, CCTA allows comprehensive assessment of coronary stenosis, plaque burden, left ventricular morphology, function, perfusion and viability. One concern with CCTA is the issue of ionizing radiation exposure. Recent technical progress allows dramatic reduction of radiation dose. The newest generation scanner is capable of producing CCTA of diagnostic quality with a dose of less than 1 mSv. A multisociety guideline for appropriate clinical indications for cardiac computed tomography was recently published. SUMMARY When used appropriately, CCTA has been established as a valid noninvasive imaging alternative to ICA in selected patients at low to intermediate risk of CAD.
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Rojas CA, Jaimes CE, El-Sherief AH, Medina HM, Chung JH, Ghoshhajra B, Abbara S. Cardiac CT of non-shunt pathology of the interatrial septum. J Cardiovasc Comput Tomogr 2010; 5:93-100. [PMID: 21130061 DOI: 10.1016/j.jcct.2010.10.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2010] [Revised: 09/29/2010] [Accepted: 10/18/2010] [Indexed: 10/18/2022]
Abstract
The development and anatomy of the interatrial septum is complex. With the increasing use of cardiac CT and its precise delineation of the anatomy, it is important for the cardiac imager to become familiar with the normal anatomic structures that compose the interatrial septum and their variants. Furthermore, it is important to recognize pathologic processes occurring in this region other than atrial septal defects and potential imaging pitfalls. This pictorial essay provides a detailed review of these topics with emphasis in CT appearance and related technical aspects.
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Affiliation(s)
- Carlos A Rojas
- Department of Cardiac Imaging, Massachusetts General Hospital, Harvard Medical School, 165 Cambridge Street, Boston, MA 02114, USA.
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