1.
Ásgeirsdóttir, Helga, et al.
(författare)
Depiction of anatomic structures of relevance for scoring of cystic fibrosis changes by chest tomosynthesis and computed tomography
2014
Ingår i: Journal of Cystic Fibrosis. 37th European Cystic Fibrosis Conference, 11-14 June 2014, Gothenburg, Sweden. ; 13:Suppl. 2
Konferensbidrag (övrigt vetenskapligt/konstnärligt) abstract
Introduction: Chest radiography (CR) and computed tomography (CT) are commonly used for imaging of patients with cystic fibrosis, and scoring is applied to assess disease severity. Chest tomosynthesis (CTS) is a new imaging modality providing better anatomic visualization than CR at radiation doses and costs lower than CT. Objective: To compare visibility and size of anatomic structures of relevance for scoring in CTS and CT images. Methods: 21 adult patients with cystic fibrosis were examined both with CTS (VolumeRAD; GE Healthcare) and volumetric CT (LightSpeed Pro 16, LightSpeed VCT, Discovery CT750HD; GE healthcare and Somatom Definition, Siemens Medical Solutions). The average effective dose for a standard patient was 0.13 and 4.5 mSv for CTS and CT, respectively. Comparison of visibility and manual measurements of diameters of the central and peripheral bronchi and their accompanying artery, as well as bronchial wall thickness (BWT), were performed in a non-blinded fashion. Results: All central structures could be evaluated. Mean difference in diameter of central bronchi, accompanying artery and BWT between CTS and CT was −0.6 (SD 0.6), −0.7 (SD 0.7) and −0.4 (SD 0.2) mm, respectively. Peripheral structures were more difficult to assess by CTS. Peripheral bronchial diameter, BWT and diameter of accompanying artery could be assessed by CTS in 20, 15 and 4 cases, respectively and mean difference between measurements was −0.5 (SD 0.5), −0.3 (SD 0.3) and −0.4 (SD 0.4) mm, respectively. Conclusion: This study indicates that peripheral structures are more difficult to evaluate by CTS and that CTS slightly underestimate size of structures in comparison to CT
2.
Pullerits, Rille, 1969, et al.
(författare)
Off-Trial Evaluation of the B cell-Targeting Treatment in the Refractory Cases of Antineutrophil Cytoplasmic Antibodies (ANCA)-Associated Vasculitis: Long-Term Follow-Up from a Single Centre.
2012
Ingår i: Scandinavian journal of immunology. - : Wiley. - 1365-3083 .- 0300-9475. ; 76:4, s. 411-20
Tidskriftsartikel (refereegranskat) abstract
The aim of the study was to evaluate long-term clinical and immunological effects of anti-B cell treatment in patients with antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis refractory to conventional immunosuppressive treatment. Rituximab (RTX) was added to the ongoing immunosuppressive treatment in 29 patients with refractory ANCA-associated vasculitis. The disease activity was measured using Birmingham Vasculitis Activity Score/Wegener's granulomatosis (BVAS/WG score), and clinical laboratory variables were recorded. The median BVAS/WG score before treatment was 6 (IQR 3-8), and 28 patients (97%) had disease flare classified either severe (62%) or limited (34%). Six of 29 patients (21%) achieved a complete remission, and 12 (41%) had a treatment response with ≥50% decrease in BVAS/WG score at 6months. Fourteen patients (64%) with kidney involvement achieved remission, and in seven patients (50%), no flare was seen during the follow-up period. Three patients had renal flare and were successfully re-treated with RTX. Seventeen patients had disease symptoms from airways and eyes at RTX initiation, whereas only 29% displayed ≥50% treatment response. Limited clinical improvement was seen in patients with endobronchial lesions and trachea-subglottic granulomatous disease. RTX is a potent therapeutic option for ANCA-associated vasculitis refractory to conventional treatment. Best response may be expected in patients with vasculitic manifestations.
3.
4.
Asplund, Sara, 1976, et al.
(författare)
Extended analysis of the effect of learning with feedback on the detectability of pulmonary nodules in chest tomosynthesis
2011
Ingår i: Progress in Biomedical Optics and Imaging - Proceedings of SPIE. - : SPIE. - 1605-7422. ; 7966
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt) 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.
(författare)
Learning aspects and potential pitfalls regarding detection of pulmonary nodules in chest tomosynthesis and proposed related quality criteria.
2011
Ingår i: Acta radiologica. - : SAGE Publications. - 1600-0455 .- 0284-1851. ; 52:5, s. 503-512
Tidskriftsartikel (refereegranskat) 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.
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9.
Johnsson, Åse (Allansdotter), 1966, et al.
(författare)
A phantom study of nodule size evaluation with chest tomosynthesis and computed tomography.
2010
Ingår i: Radiation protection dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 139:1-3, s. 140-143
Tidskriftsartikel (refereegranskat) 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.
10.
Johnsson, Åse (Allansdotter), 1966, et al.
(författare)
A Retrospective Study of Chest Tomosynthesis as a Tool for Optimizing the use of Computed Tomography Resources and Reducing Patient Radiation Exposure
2014
Ingår i: Academic Radiology. - : Elsevier BV. - 1076-6332. ; 21:11, s. 1427-1433
Tidskriftsartikel (refereegranskat) abstract
Rationale and Objectives: To investigate potential benefits and drawbacks of the clinical use of chest tomosynthesis (CTS), to what extent CTS obviates the need for chest computed tomography (CT), and what reduction in radiation dose thereby can be achieved. Materials and Methods: The Regional Ethical Review Board approved the follow-up study of patients examined with CTS as part of clinical routine. For each case, two radiologists in consensus determined whether CT would have been performed, had CTS not been an option, and whether CTS was an adequate examination. Thereafter, it was determined whether the use of CTS instead of CT in retrospect was beneficial, neutral, or detrimental for the radiological work-up. The radiation dose to the patient population was determined both for the actual clinical situation and for the alternative scenario that would result, had CTS not been available. Results: During 1 month 3.5 years before the survey, 149 patients (74 women, age 18-91 years) had undergone CTS for clinical purposes. It was judged that CT would have been performed in 100 cases, had CTS not been available, and that CTS obviated the need for CT in 80 cases. CTS was judged as beneficial, neutral, and detrimental for the radiological work-up in 85, 13, and two cases, respectively. For the entire study population, the use of CTS decreased the average effective dose from 2.7 to 0.7 mSv. Conclusions: The present study indicates that CTS may have benefits for the radiological work-up as it has the potential to both optimize the use of CT resources and reduce the effective dose to the patient population. A drawback is that CTS examinations may fail to reveal pathology visible with CT and in clinically doubtful cases further investigations including other imaging procedures should be considered.
