| 1. |
- Bergström, Göran, 1964, et al.
(author)
-
Prevalence of Subclinical Coronary Artery Atherosclerosis in the General Population
- 2021
-
In: Circulation. - Philadelphia : American Heart Association. - 0009-7322 .- 1524-4539. ; 144:12, s. 916-929
-
Journal article (peer-reviewed)abstract
- Background: Early detection of coronary atherosclerosis using coronary computed tomography angiography (CCTA), in addition to coronary artery calcification (CAC) scoring, may help inform prevention strategies. We used CCTA to determine the prevalence, severity, and characteristics of coronary atherosclerosis and its association with CAC scores in a general population.Methods: We recruited 30 154 randomly invited individuals age 50 to 64 years to SCAPIS (the Swedish Cardiopulmonary Bioimage Study). The study includes individuals without known coronary heart disease (ie, no previous myocardial infarctions or cardiac procedures) and with high-quality results from CCTA and CAC imaging performed using dedicated dual-source CT scanners. Noncontrast images were scored for CAC. CCTA images were visually read and scored for coronary atherosclerosis per segment (defined as no atherosclerosis, 1% to 49% stenosis, or ≥50% stenosis). External validity of prevalence estimates was evaluated using inverse probability for participation weighting and Swedish register data.Results: In total, 25 182 individuals without known coronary heart disease were included (50.6% women). Any CCTA-detected atherosclerosis was found in 42.1%; any significant stenosis (≥50%) in 5.2%; left main, proximal left anterior descending artery, or 3-vessel disease in 1.9%; and any noncalcified plaques in 8.3% of this population. Onset of atherosclerosis was delayed on average by 10 years in women. Atherosclerosis was more prevalent in older individuals and predominantly found in the proximal left anterior descending artery. Prevalence of CCTA-detected atherosclerosis increased with increasing CAC scores. Among those with a CAC score >400, all had atherosclerosis and 45.7% had significant stenosis. In those with 0 CAC, 5.5% had atherosclerosis and 0.4% had significant stenosis. In participants with 0 CAC and intermediate 10-year risk of atherosclerotic cardiovascular disease according to the pooled cohort equation, 9.2% had CCTA-verified atherosclerosis. Prevalence estimates had excellent external validity and changed marginally when adjusted to the age-matched Swedish background population.Conclusions: Using CCTA in a large, random sample of the general population without established disease, we showed that silent coronary atherosclerosis is common in this population. High CAC scores convey a significant probability of substantial stenosis, and 0 CAC does not exclude atherosclerosis, particularly in those at higher baseline risk.
|
|
| 2. |
- Flinck, Marianne, et al.
(author)
-
Cardiac output measured by electrical velocimetry in the CT suite correlates with coronary artery enhancement: a feasibility study.
- 2010
-
In: Acta radiologica. - : SAGE Publications. - 1600-0455 .- 0284-1851. ; 51:8, s. 895-902
-
Journal article (peer-reviewed)abstract
- Background: Cardiac output (CO) is inversely related to vascular contrast medium (CM) enhancement during computed tomography (CT). Impedance cardiography with a new technique, electrical velocimetry (EV), may create opportunities to measure CO pre-examination for adaptation of CM injection parameters. Purpose: To relate COEV measured by radiology staff to aortic attenuation as a measure of coronary artery attenuation during CT coronary angiography (CTCA), and to formulate a tentative statistical model to adapt CM injection parameters to CO. Material and Methods: COEV was measured immediately before 100 kVp CTCA (64-multirow detector) in 27 patients with presumed coronary artery disease. For CTCA, 260 mg I/kg (maximum dosage weight: 80/90 kg for women/men) was injected intravenously during 12 s. Simple linear regression analysis was performed to explore the correlation between aortic attenuation (Hounsfield units, HU) and body weight, the influence of COEV on aortic attenuation adjusted to injected CM dose rate (HU per mg I/kg/s), and to establish a tentative formula on how to adapt CM injection parameters to COEV and desired aortic attenuation. Results: The correlation between aortic attenuation and body weight was weak and non-significant (r=−0.14 after outlier exclusion). A significant negative correlation (r=−0.63) was found between aortic attenuation adjusted to injected CM dose rate (HU per mg I/kg/s) and COEV. The resulting formula, CM dose rate=COEV×(aortic attenuation−240)/55, made it possible to calculate CM volumes and injection rates at various COs and, for example, the present mean aortic attenuation (438 HU), injection time (12 s), CM concentration (320 mg I/ml), and a certain body weight. Conclusion: EV makes it possible to measure CO in the CT suite before vascular examinations. Hence, CM doses may be decreased in low CO states to reduce the risk of CM-induced nephropathy without jeopardizing diagnostic quality and may be increased in high CO states to avoid poor enhancement.
|
|
| 3. |
|
|
| 4. |
- Asplund, Sara, 1976, et al.
(author)
-
Extended analysis of the effect of learning with feedback on the detectability of pulmonary nodules in chest tomosynthesis
- 2011
-
In: Progress in Biomedical Optics and Imaging - Proceedings of SPIE. - : SPIE. - 1605-7422. ; 7966
-
Journal article (other academic/artistic)abstract
- In chest tomosynthesis, low-dose projections collected over a limited angular range are used for reconstruction of section images of the chest, resulting in a reduction of disturbing anatomy at a moderate increase in radiation dose compared to chest radiography. In a previous study, we investigated the effects of learning with feedback on the detection of pulmonary nodules in chest tomosynthesis. Six observers with varying degrees of experience of chest tomosynthesis analyzed tomosynthesis cases for presence of pulmonary nodules. The cases were analyzed before and after learning with feedback. Multidetector computed tomography (MDCT) was used as reference. The differences in performance between the two readings were calculated using the jackknife alternative free-response receiver operating characteristics (JAFROC-2) as primary measure of detectability. Significant differences between the readings were found only for observers inexperienced in chest tomosynthesis. The purpose of the present study was to extend the statistical analysis of the results of the previous study, including JAFROC-1 analysis and FROC curves in the analysis. The results are consistent with the results of the previous study and, furthermore, JAFROC-1 gave lower p-values than JAFROC-2 for the observers who improved their performance after learning with feedback. © 2011 SPIE.
|
|
| 5. |
|
|
| 6. |
- Asplund, Sara, 1976, et al.
(author)
-
Learning aspects and potential pitfalls regarding detection of pulmonary nodules in chest tomosynthesis and proposed related quality criteria.
- 2011
-
In: Acta radiologica. - : SAGE Publications. - 1600-0455 .- 0284-1851. ; 52:5, s. 503-512
-
Journal article (peer-reviewed)abstract
- Background In chest tomosynthesis, low-dose projections collected over a limited angular range are used for reconstruction of an arbitrary number of section images of the chest, resulting in a moderately increased radiation dose compared to chest radiography. Purpose To investigate the effects of learning with feedback on the detection of pulmonary nodules for observers with varying experience of chest tomosynthesis, to identify pitfalls regarding detection of pulmonary nodules, and present suggestions for how to avoid them, and to adapt the European quality criteria for chest radiography and computed tomography (CT) to chest tomosynthesis. Material and Methods Six observers analyzed tomosynthesis cases for presence of nodules in a jackknife alternative free-response receiver-operating characteristics (JAFROC) study. CT was used as reference. The same tomosynthesis cases were analyzed before and after learning with feedback, which included a collective learning session. The difference in performance between the two readings was calculated using the JAFROC figure of merit as principal measure of detectability. Results Significant improvement in performance after learning with feedback was found only for observers inexperienced in tomosynthesis. At the collective learning session, localization of pleural and subpleural nodules or structures was identified as the main difficulty in analyzing tomosynthesis images. Conclusion The results indicate that inexperienced observers can reach a high level of performance regarding nodule detection in tomosynthesis after learning with feedback and that the main problem with chest tomosynthesis is related to the limited depth resolution.
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
- Engström, Gunnar, et al.
(author)
-
The Swedish CArdioPulmonary BioImage Study : objectives and design
- 2015
-
In: Journal of Internal Medicine. - : Wiley. - 0954-6820 .- 1365-2796. ; 278:6, s. 645-659
-
Journal article (peer-reviewed)abstract
- Cardiopulmonary diseases are major causes of death worldwide, but currently recommended strategies for diagnosis and prevention may be outdated because of recent changes in risk factor patterns. The Swedish CArdioPulmonarybioImage Study (SCAPIS) combines the use of new imaging technologies, advances in large-scale 'omics' and epidemiological analyses to extensively characterize a Swedish cohort of 30 000 men and women aged between 50 and 64 years. The information obtained will be used to improve risk prediction of cardiopulmonary diseases and optimize the ability to study disease mechanisms. A comprehensive pilot study in 1111 individuals, which was completed in 2012, demonstrated the feasibility and financial and ethical consequences of SCAPIS. Recruitment to the national, multicentre study has recently started.
|
|
| 10. |
|
|
| 11. |
- Fagman, Erika, et al.
(author)
-
Increased aortic wall thickness on CT as a sign of prosthetic valve endocarditis.
- 2016
-
In: Acta radiologica (Stockholm, Sweden : 1987). - : SAGE Publications. - 1600-0455 .- 0284-1851. ; 57:12, s. 1476-1482
-
Journal article (peer-reviewed)abstract
- Increased wall thickness in the aortic root has been suggested as an early sign of prosthetic valve endocarditis (PVE). However, there are no previous studies on the aortic wall thickness after aortic valve replacement (AVR) or in patients with PVE.
|
|
| 12. |
|
|
| 13. |
- Flinck, Agneta, 1953
(author)
-
Electrophysiological effects of contrast media. Dynamic vectorcardiographic monitoring of patients during coronary angiography
- 2001
-
Doctoral thesis (other academic/artistic)abstract
- Objective: The aims of this work were to study, by means of dynamic vectorcardiography (VCG), the electrophysiological effects of contrast media (CM) injected into the coronary arteries and to evaluate which VCG variables are most suitable for comparing different CM. We also studied if CM-induced VCG changes differ from those seen after myocardial ischaemia. The clinical significance of the VCG changes was evaluated by comparing the frequency of cardiac adverse events (CAE) during cardioangiography in an unselected patient population.Methods: The VCG recordings were carried out using the MIDA 1000 system. This system provides on-line information about changes in the different phases of the ECG-complex by means of continuously calculated VCG variables, such as QRS-vd, QRSC-va, STC-vm and TC-vm. This technique was used in three coronary angiography studies where changes induced by CM (iohexol, iohexol/Na, iodixanol and ioxaglate) were analysed and compared. In another study CM related changes (iohexol) were compared with those from acetated Ringer injections and ischaemia during percutaneous transluminal angioplasty. The clinical relevance of the VCG changes induced by iohexol and iodixanol was assessed by registering the frequency of CAE up to 24 hours after cardioangiography in a total of 1020 patients receiving either of these two CM.Results: All CM induced changes in several VCG variables, in particular QRS-vd, QRSC-va and TC-vm were affected. Iodixanol caused significantly less VCG changes than both iohexol and ioxaglate. Ioxaglate induced the largest relative change in TC-vm. QRS-vd was more affected by iohexol injections in the left coronary artery than by ischaemia in the left anterior descending artery, while ischaemia induced the largest change in STC-vm. Both iohexol and iodixanol were well tolerated when used in an unselected patient population, but there was a trend that iodixanol induced fewer CAE. Conclusions: Dynamic vectorcardiography makes it easy to follow and quantitate CM induced electrophysiological changes. QRS-vd, QRSC-va and TC-vm seem best suited to monitor CM effects. Patients with unstable angina pectoris, old age and female gender might benefit from the use of iodixanol, the CM that affected VCG variables the least.
|
|
| 14. |
- Håkansson, Markus, et al.
(author)
-
Nodule detection in digital chest radiography: effect of nodule location.
- 2005
-
In: Radiation protection dosimetry. - : Oxford University Press (OUP). - 0144-8420 .- 1742-3406. ; 114:1-3, s. 92-6
-
Journal article (peer-reviewed)abstract
- Most detection studies in chest radiography treat the entire chest image as a single background or divided into the two regions parenchyma and mediastinum. However, the different parts of the lung show great variations in attenuation and structure, leading to different amounts of quantum noise and scattered radiation as well as different complexity. Detailed data on the difference in detectability in the different regions are of importance. The purpose of this study was to quantify the difference in detectability between different regions of a chest image. The chest X ray was divided into six different regions, where each region was considered to be uniform in terms of detectability. Thirty clinical chest images were collected and divided into the different regions. Simulated designer nodules with a full-width-at-fifth-maximum of 10 mm but with varying contrast were added to the images. An equal number of images lacking pathology were included and a receiver operating characteristic (ROC) study was conducted with five observers. Results show that the image contrast needed to obtain a constant value of A(z) (area under an ROC curve) differs by more than a factor of four between different regions.
|
|
| 15. |
- Johnsson, Åse (Allansdotter), 1966, et al.
(author)
-
A phantom study of nodule size evaluation with chest tomosynthesis and computed tomography.
- 2010
-
In: Radiation protection dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 139:1-3, s. 140-143
-
Journal article (peer-reviewed)abstract
- The aim of the present study was to investigate nodule size measurements with chest tomosynthesis (TS) and computed tomography (CT). A 26-mm thick phantom, composed of a Polylite block with embedded spheres of different materials and sizes (4-20 mm), was scanned by both CT and TS. Six observers without prior knowledge of the true diameters of the spheres independently measured the diameter of the spheres on the CT and TS images. Four observers were allowed to change the window settings and two of the observers used predetermined fixed viewing conditions. The mean relative errors for all observers and all measured spheres compared with the known diameter of the spheres were 1.4 % (standard deviation, SD: 5.4 %) on CT images and -1.1 % (SD: 5.0 %) on TS images. With regard to the four observers where the window settings were at the discretion of the observer, the mean relative errors were 1.4 % (SD: 6.4 %) on CT images and -1.7 % (SD: 5.7 %) on TS images. Regarding the two observers using identical viewing conditions the mean relative error was 1.5 % (SD: 2.8 %) on CT images and 0.2 % (SD: 2.6 %) on TS images. In conclusion, the study suggests that nodule size measurements on chest TS might be an alternative to measurements on CT.
|
|
| 16. |
|
|
| 17. |
|
|
| 18. |
- Johnsson, Åse (Allansdotter), 1966, et al.
(author)
-
Incidental findings and their handling in the Swedish CArdioPulmonary bioimage study (SCAPIS)
- 2017
-
In: Incidental Radiological Findings. - Cham : Springer International Publishing. - 0942-5373 .- 2197-4187. - 9783319425818 - 9783319425795 - 9783319826127 ; , s. 91-101
-
Book chapter (peer-reviewed)abstract
- The Swedish CArdioPulmonary bioImage Study (SCAPIS) combines the use of new imaging technologies, large-scale proteomics/metabolomics/genomics, and epidemiological analyses to extensively characterize a Swedish cohort of 30,000 men and women aged between 50 and 64 years. Its main aims are to improve risk prediction and to optimize our ability to study mechanisms of cardiopulmonary diseases. SCAPIS is currently recruiting at six sites in Sweden, and a pilot study was conducted in 2012 to test the feasibility of the comprehensive study protocol. In the planning phase, it was recognized that the detailed phenotyping used in SCAPIS would identify a large number of clinical findings in need of medical attention. This was confirmed by evaluation of results from the pilot study. Here we focus on pulmonary nodules and asymptomatic coronary artery stenosis. These clinical features were observed in a large number of participants, and the clinical handing and prognosis related to these observations are unclear. They thus posed great challenges for the study in their practical and ethical handling. This chapter describes how we developed procedures to handle these findings based on existing evidence and expert consensus as well as deliberations on ethical issues.
|
|
| 19. |
- Johnsson, Åse (Allansdotter), 1966, et al.
(author)
-
Nodule detection by chest tomosynthesis
- 2009
-
In: 2nd World Congress of Thoracic Imaging and Diagnosis in Chest Disease, 30 May-2 June 2009, Valencia, Spain.
-
Conference paper (other academic/artistic)
|
|
| 20. |
- Johnsson, Åse (Allansdotter), 1966, et al.
(author)
-
Overview of two years of clinical experience of chest tomosynthesis at Sahlgrenska University Hospital.
- 2010
-
In: Radiation protection dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 139:1-3, s. 124-129
-
Journal article (peer-reviewed)abstract
- Since December 2006, approximately 3800 clinical chest tomosynthesis examinations have been performed at our department at Sahlgrenska University Hospital. A subset of the examinations has been included in studies of the detectability of pulmonary nodules, using computed tomography (CT) as the gold standard. Visibility studies, in which chest tomosynthesis and CT have been compared side-by side, have been used to determine the depiction potential of chest tomosynthesis. Comparisons with conventional chest radiography have been made. In the clinical setting, chest tomosynthesis has mostly been used as an additional examination. The most frequent indication for chest tomosynthesis has been suspicion of a nodule or tumour. In visibility studies, tomosynthesis has depicted over 90 % of the nodules seen on the CT scan. The corresponding figure for chest radiography has been <30 %. In the detection studies, the lesion-level sensitivity has been approximately 60 % for tomosynthesis and 20 % for chest radiography. In one of the detection studies, an analysis of all false-positive nodules was performed. This analysis showed that all findings had morphological correlates on the CT examinations. The majority of the false-positive nodules were localised in the immediate subpleural region. In conclusion, chest tomosynthesis is an improved chest radiography method, which can be used to optimise the use of CT resources, thereby reducing the radiation dose to the patient population. However, there are some limitations with chest tomosynthesis. For example, patients undergoing tomosynthesis have to be able to stand still and hold their breath firmly for 10 s. Also, chest tomosynthesis has a limited depth resolution, which may explain why pathology in the subpleural region is more difficult to interpret and artefacts from medical devices may occur.
|
|
| 21. |
- Johnsson, Åse (Allansdotter), 1966, et al.
(author)
-
Pulmonary nodule size evaluation with chest tomosynthesis.
- 2012
-
In: Radiology. - : Radiological Society of North America (RSNA). - 1527-1315 .- 0033-8419. ; 265:1, s. 273-82
-
Journal article (peer-reviewed)abstract
- Purpose: To evaluate intra- and interobserver variability, as well as agreement for nodule size measurements on chest tomosynthesis and computed tomographic (CT) images. Materials and Methods: The Regional Ethical Review Board approved this study, and all participants gave written informed consent. Thirty-six segmented nodules in 20 patients were included in the study. Eight observers measured the left-to-right, inferior-to-superior, and longest nodule diameters on chest tomosynthesis and CT images. Intra- and interobserver repeatability, as well as agreement between measurements on chest tomosynthesis and CT images, were assessed as recommended by Bland and Altman. Results: The difference between the mean manual and the segmented diameter was -2.2 and -2.3 mm for left-to-right and -2.6 and -2.2 mm for the inferior-to-superior diameter for measurements on chest tomosynthesis and CT images, respectively. Intraobserver 95% limits of agreement (LOA) for the longest diameter ranged from a lower limit of -1.1 mm and an upper limit of 1.0 mm to -1.8 and 1.8 mm for chest tomosynthesis and from -0.6 and 0.9 mm to -3.1 and 2.2 mm for axial CT. Interobserver 95% LOA ranged from -1.3 and 1.5 mm to -2.0 and 2.1 mm for chest tomosynthesis and from -1.8 and 1.1 mm to -2.2 and 3.1 mm for axial CT. The 95% LOA concerning the mean of the observers' measurements of the longest diameter at chest tomosynthesis and axial CT were ±2.1 mm (mean measurement error, 0 mm). For the different observers, the 95% LOA between the modalities ranged from -2.2 and 1.6 mm to -3.2 and 2.8 mm. Conclusion: Measurements on chest tomosynthesis and CT images are comparable, because there is no evident bias between the modalities and the repeatability is similar. The LOA between measurements for the two modalities raise concern if measurements from chest tomosynthesis and CT were to be used interchangeably. © RSNA, 2012 Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12111459/-/DC1.
|
|
| 22. |
- Karlsson, Martin, 1978, et al.
(author)
-
Prophylactic fibrinogen infusion reduces bleeding after coronary artery bypass surgery
- 2009
-
In: Thrombosis & Haemostasis. ; 102, s. 137-144
-
Journal article (peer-reviewed)abstract
- It has been suggested that preoperative fibrinogen plasma concentration is independently associated to postoperative blood loss after cardiac surgery. Theoretically, prophylactic infusion of fibrinogen concentrate may thus reduce postoperative bleeding, but this has not previously been investigated. Twenty elective coronary artery bypass graft (CABG) patients with preoperative plasma fibrinogen levels <3.8 g/l were included in a prospective randomised pilot study. Patients were randomised to receive an infusion of 2 g fibrinogen concentrate (FIB group) or no infusion before surgery (control group). Primary endpoint was safety with clinical adverse events and graft occlusion assessed by multi-slice computed tomography. Predefined secondary endpoints were postoperative blood loss, blood transfusions, haemoglobin levels 24 hours (h) after surgery, and global haemostasis assessed with thromboelastometry, 2 and 24 hours after surgery. Infusion of 2 g fibrinogen concentrate increased plasma levels of fibrinogen by 0.6 ± 0.2 g/l. There were no clinically detectable adverse events of fibrinogen infusion. Computed tomography revealed one subclinical vein graft occlusion in the FIB group. Fibrinogen concentrate infusion reduced postoperative blood loss by 32% (565 ± 150 vs. 830 ± 268 ml/12 h, p=0.010). Haemoglobin concentration was significantly higher 24 h after surgery in the FIB group(110 ± 12 vs. 98 ± 8 g/l, p=0.018). Prophylactic fibrinogen concentrate infusion did not influence global postoperative haemostasis as assessed by thromboelastometry. In conclusion, in this pilot study preoperative fibrinogen concentrate infusion reduced bleeding after CABG without evidence of postoperative hypercoagulability. Larger studies are necessary to ensure safety and confirm efficacy of prophylactic fibrinogen treatment in cardiac surgery.
|
|
| 23. |
|
|
| 24. |
- Perrotta, S., et al.
(author)
-
Left thoracotomy for recurrent left ventricular pseudoaneurysm
- 2010
-
In: Journal of cardiovascular medicine (Hagerstown, Md.). - 1558-2035.
-
Journal article (peer-reviewed)abstract
- A 63-year-old man developed a left ventricular pseudoaneurysm 6 months after surgery for coronary artery disease, mitral valve insufficiency and left ventricular aneurysm. The grafts were patent and the mitral valve competent, so it was decided to resect the pseudoaneurysm. The heart was approached through a left posterolateral thoracotomy using a femoral arteriovenous cardiopulmonary bypass with moderate hypothermia (25 degrees C) and fibrillatory arrest. The postoperative course was uneventful. At follow-up, 55 months after surgery, the patient is doing well and magnetic resonance reveals absence of pseudoaneurysm and increased left ventricular ejection fraction. In patients with left ventricular pseudoaneurysm undergoing redo surgery, especially in the presence of patent coronary grafts, left thoracotomy seems to be a suitable alternative to full sternotomy.
|
|
| 25. |
|
|
| 26. |
- Svalkvist, Angelica, et al.
(author)
-
Evaluation of an improved method of simulating lung nodules in chest tomosynthesis
- 2012
-
In: Acta Radiologica. - : SAGE Publications. - 0284-1851 .- 1600-0455. ; 53:8, s. 874-884
-
Journal article (peer-reviewed)abstract
- Background: Simulated pathology is a valuable complement to clinical images in studies aiming at evaluating an imaging technique. In order for a study using simulated pathology to be valid, it is important that the simulated pathology in a realistic way reflect the characteristics of real pathology. Purpose: To perform a thorough evaluation of a nodule simulation method for chest tomosynthesis, comparing the detection rate and appearance of the artificial nodules with those of real nodules in an observer performance experiment. Material and Methods: A cohort consisting of 64 patients, 38 patients with a total of 129 identified pulmonary nodules and 26 patients without identified pulmonary nodules, was used in the study. Simulated nodules, matching the real clinically found pulmonary nodules by size, attenuation, and location, were created and randomly inserted into the tomosynthesis section images of the patients. Three thoracic radiologists and one radiology resident reviewed the images in an observer performance study divided into two parts. The first part included nodule detection and the second part included rating of the visual appearance of the nodules. The results were evaluated using a modified receiver-operating characteristic (ROC) analysis. Results: The sensitivities for real and simulated nodules were comparable, as the area under the modified ROC curve (AUC) was close to 0.5 for all observers (range, 0.43-0.55). Even though the ratings of visual appearance for real and simulated nodules overlapped considerably, the statistical analysis revealed that the observers to were able to separate simulated nodules from real nodules (AUC values range 0.70-0.74). Conclusion: The simulation method can be used to create artificial lung nodules that have similar detectability as real nodules in chest tomosynthesis, although experienced thoracic radiologists may be able to distinguish them from real nodules.
|
|
| 27. |
- Vikgren, Jenny, 1957, et al.
(author)
-
Comparison of chest tomosynthesis and chest radiography for detection of pulmonary nodules: human observer study of clinical cases.
- 2008
-
In: Radiology. - : Radiological Society of North America (RSNA). - 1527-1315 .- 0033-8419. ; 249:3, s. 1034-1041
-
Journal article (peer-reviewed)abstract
- PURPOSE: To compare chest tomosynthesis with chest radiography in the detection of pulmonary nodules by using multidetector computed tomography (CT) as the reference method. MATERIALS AND METHODS: The Regional Ethical Review Board approved this study, and all participants gave informed consent. Four thoracic radiologists acted as observers in a jackknife free-response receiver operating characteristic (JAFROC) study conducted in 42 patients with and 47 patients without pulmonary nodules examined with chest tomosynthesis and chest radiography. Multidetector CT served as reference method. The observers marked suspected nodules on the images by using a four-point rating scale for the confidence of presence. The JAFROC figure of merit was used as the measure of detectability. The number of lesion localizations relative to the total number of lesions (lesion localization fraction [LLF]) and the number of nonlesion localizations relative to the total number of cases (nonlesion localization fraction [NLF]) were determined. RESULTS: Performance of chest tomosynthesis was significantly better than that of chest radiography with regard to detectability (F statistic = 32.7, df = 1, 34.8, P < .0001). For tomosynthesis, the LLF for the smallest nodules (< or = 4 mm) was 0.39 and increased with an increase in size to an LLF for the largest nodules (> 8 mm) of 0.83. The LLF for radiography was small, except for the largest nodules, for which it was 0.52. In total, the LLF was three times higher for tomosynthesis. The NLF was approximately 50% higher for tomosynthesis. CONCLUSION: For the detection of pulmonary nodules, the performance of chest tomosynthesis is better, with increased sensitivity especially for nodules smaller than 9 mm, than that of chest radiography.
|
|
| 28. |
- Vikgren, Jenny, 1957, et al.
(author)
-
High-resolution computed tomography with 16-row MDCT: A comparison regarding visibility and motion artifacts of dose-modulated thin slices and "step and shoot" images
- 2008
-
In: Acta Radiologica. - : SAGE Publications. - 0284-1851 .- 1600-0455. ; 49:7, s. 755-760
-
Journal article (peer-reviewed)abstract
- Background: Dose modulation can be used to reduce the radiation dose in computed tomography (CT) examinations while still obtaining the necessary diagnostic image quality. Multidetector-row computed tomography (MDCT) provides the possibility of simultaneous reconstruction of thin and thick slices from the same raw data. Purpose: To compare thin slices reconstructed from a dose-modulated helical acquisition and conventional high-resolution computed tomography (HRCT) images taken with the “step and shoot” technique in terms of visibility and motion artifacts, in order to investigate the possibility of excluding “step and shoot” acquisition from the HRCT examination. Material and Methods: Twenty patients were examined by a dose-modulated helical acquisition, “MDCT smart mA,” and by a noncontiguous cross-sectional high-resolution 16-row MDCT examination, “MDCT step and shoot.” Images from four anatomical levels, made anonymous regarding identity and technical data, were analyzed in random order by four thoracic radiologists. Results: “MDCT smart mA” was worse than “MDCT step and shoot” in terms of visibility. Concerning motion artifacts, “MDCT smart mA” was better than “MDCT step and shoot.” Conclusion: Thin images reconstructed from a dose-modulated 16-row helical MDCT acquisition (“MDCT smart mA”), as performed in our study, do not provide sufficient image quality regarding visibility compared to the “MDCT step and shoot” technique for the latter technique to be excluded from the HRCT examination.
|
|
| 29. |
- Vikgren, Jenny, 1957, et al.
(author)
-
High-Resolution Computed Tomography with Single-Slice Computed Tomography and 16-Channel Multidetector Computed Tomography: A Comparison Regarding Visibility and Motion Artifacts
- 2007
-
In: Acta Radiologica. - : SAGE Publications. - 0284-1851 .- 1600-0455. ; 48:9, s. 956-961
-
Journal article (peer-reviewed)abstract
- Background: High-resolution computed tomography is the image procedure of choice in the evaluation of interstitial lung disease. Multidetector-row computed tomography provides the possibility of simultaneous reconstruction of thin and thick slices from the same raw data, acquired from one single series. Thus, it may be tempting to exclude the step-and-shoot series. Purpose: To compare high-resolution computed tomography (HRCT step-and-shoot) from single-slice CT (SSCT) and 16-channel multidetector CT (MDCT) in terms of visibility and motion artifacts, and to investigate whether thin images reconstructed from helical MDCT are equal to or better than conventional HRCT by SSCT in terms of visibility and motion artifacts. Material and Methods: 20 patients underwent HRCT step-and-shoot by SSCT (SSCT step-and-shoot) and MDCT (MDCT step-and-shoot), and a helical MDCT acquisition (MDCT helical). Images from four anatomical levels were analyzed in random order regarding visibility and motion artifacts. Results: Visibility using MDCT step-and-shoot was significantly better than or equal to SSCT step-and-shoot for segmental bronchi and fissures, but not for subsegmental bronchi. For MDCT helical, visibility was equal to or better than SSCT step-and-shoot for segmental bronchi, but not for fissures and subsegmental bronchi. Concerning motion artifacts, MDCT step-and-shoot and MDCT helical were significantly better than or equal to SSCT step-and-shoot. Conclusion: The image quality (accounting for motion artifacts and visibility) of SSCT step-and-shoot and MDCT step-and-shoot is comparable. The visibility of anatomic structures in images from MDCT helical is inferior to HRCT step-and-shoot.
|
|
| 30. |
|
|
| 31. |
- Zachrisson, Sara, et al.
(author)
-
Effect of clinical experience of chest tomosynthesis on detection of pulmonary nodules.
- 2009
-
In: Acta radiologica. - : SAGE Publications. - 1600-0455 .- 0284-1851. ; 50:8, s. 884-891
-
Journal article (peer-reviewed)abstract
- BACKGROUND: The new technique chest tomosynthesis refers to the principle of collecting low-dose projections of the chest at different angles and using these projections to reconstruct section images of the chest at a radiation dose comparable to that of chest radiography. PURPOSE: To investigate if, for experienced thoracic radiologists, the detectability of pulmonary nodules obtained after only a short initial learning period of chest tomosynthesis improves with additional clinical experience of the new technique. MATERIAL AND METHODS: Two readings of the same clinical chest tomosynthesis cases, the first performed after 6 months of clinical experience and the second after an additional period of 1 year, were conducted. Three senior thoracic radiologists, with more than 20 years of experience of chest radiography, acted as observers, with the task of detecting pulmonary nodules in a jackknife free-response receiver operating characteristics (JAFROC1) study. The image material consisted of 42 patients with and 47 patients without pulmonary nodules examined with chest tomosynthesis. Multidetector computed tomography (MDCT) was used as a reference. The total number of nodules was 131. The JAFROC1 figure of merit (FOM) was used as the principal measure of detectability. RESULTS: The difference in the observer-averaged JAFROC1 FOM of the two readings was 0.004 (95% confidence interval: -0.11, 0.12; F-statistic: 0.01 on 1 and 2.65 df; P=0.91). Thus, no significant improvement in detectability was found after the additional clinical experience of tomosynthesis. CONCLUSION: The study indicates that experienced thoracic radiologists already within the first months of clinical use of chest tomosynthesis are able to take advantage of the new technique in the task of detecting pulmonary nodules.
|
|
| 32. |
|
|
| 33. |
- Zachrisson, Sara, et al.
(author)
-
Evaluation of chest tomosynthesis for the detection of pulmonary nodules: Effect of clinical experience and comparison with chest radiography
- 2009
-
In: Progress in Biomedical Optics and Imaging - Proceedings of SPIE. - : SPIE. - 1605-7422. ; 7263
-
Journal article (other academic/artistic)abstract
- Chest tomosynthesis refers to the technique of collecting low-dose projections of the chest at different angles and using these projections to reconstruct section images of the chest. In this study, a comparison of chest tomosynthesis and chest radiography in the detection of pulmonary nodules was performed and the effect of clinical experience of chest tomosynthesis was evaluated. Three senior thoracic radiologists, with more than ten years of experience of chest radiology and 6 months of clinical experience of chest tomosynthesis, acted as observers in a jackknife free-response receiver operating characteristics (JAFROC-1) study, performed on 42 patients with and 47 patients without pulmonary nodules examined with both chest tomosynthesis and chest radiography. Multidetector computed tomography (MDCT) was used as reference and the total number of nodules found using MDCT was 131. In order to investigate the effect of additional clinical experience of chest tomosynthesis, a second reading session of the tomosynthesis images was performed one year after the initial one. The JAFROC-1 figure of merit (FOM) was used as the principal measure of detectability. In comparison with chest radiography, chest tomosynthesis performed significantly better with regard to detectability. The observer-averaged JAFROC-1 FOM was 0.61 for tomosynthesis and 0.40 for radiography, giving a statistically significant difference between the techniques of 0.21 (p<0.0001). The observer-averaged JAFROC-1 FOM of the second reading of the tomosynthesis cases was not significantly higher than that of the first reading, indicating no improvement in detectability from the additional clinical experience of tomosynthesis.
|
|
