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- Meltzer, Carin
(författare)
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Chest Tomosynthesis for Detection and Surveillance of Pulmonary Pathology. Studies on Cystic Fibrosis and Solid Pulmonary Nodules
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Introduction: Digital tomosynthesis (DTS) is a relatively new imaging modality in thoracic imaging. The technique is based on the equipment of conventional radiography, upgraded with a moving tube that enables separation of structures that are superimposed on chest x-ray (CXR). DTS has proven to be superior to CXR in detection of pathology, as well as a problem-solver for inconclusive findings in CXR, and has also been suggested as a low-dose / low-cost alternative to computed tomography (CT). However, the number of studies comparing DTS with CT are limited. Consequently, the overall aim of this thesis was to compare pulmonary imaging in DTS with CT, and to investigate the potential for DTS to serve as an alternative to CT. The performance of DTS was evaluated in terms of visualization, characterization, detection and follow-up of structural changes for two groups that often undergo multiple CT examinations; patients with cystic fibrosis (CF), and individuals with incidental solid pulmonary nodules. Methods: Visibility of anatomical structures in CF was studied by a head-to-head comparison of concurrently performed CT and DTS (Paper I). Estimation of extent of disease was quantified by modality-specific scoring methods on CT, DTS and CXR, in two sets of examinations for each participant, separated by three years (Paper II). The studies on pulmonary nodules were based on individuals recruited from the pilot study of the population-based Swedish CArdioPulmonary bioImage Study (SCAPIS), with incidental solid nodules requiring follow-up detected on chest CT. Participants were examined by DTS in addition to routine CT for surveillance of nodule growth. Detection rates and recommendation for follow-up were independently assessed on DTS and compared to CT (Paper III). Nodule size and change of size between two examinations were estimated by diametrical measurements on DTS and semi-automated derived diameters and volume on CT (Paper IV). Results: The studies on CF showed equal or superior visibility of anatomical structures in DTS in 48% of the cases. Structures in the anterior, posterior and lower parts of the lungs were less well depicted than those located in the central and lateral parts. Perceived visibility varied significantly among the observers (Paper I). Inter-modality correlation between DTS and CT for assessment of extent of disease was very strong regarding total severity score as well as sub-scores of bronchiectasis and bronchial wall thickening, which are key findings in CF (Paper II). Nodule detection rates in DTS were between 48 and 62% for nodules measuring 5-10 mm in diameter, with a reduced number of nodules recommended for follow-up compared to CT (Paper III). An acceptable inter-modality agreement of average diameter, but lower agreement compared to volumetric estimates on CT was found (Paper IV). In conclusion, the results indicate that DTS could be an alternative to CT in surveillance of patients with CF, and for follow-up of well-depicted solid nodules. Further studies including cases with progressive disease are warranted.
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- Meltzer, Carin, et al.
(författare)
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Detection and Characterization of Solid Pulmonary Nodules at Digital Chest Tomosynthesis: Data from a Cohort of the Pilot Swedish Cardiopulmonary Bioimage Study
- 2018
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Ingår i: Radiology. - : Radiological Society of North America (RSNA). - 0033-8419 .- 1527-1315. ; 287:3, s. 1018-1027
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To investigate the performance of digital tomosynthesis (DTS) for detection and characterization of incidental solid lung nodules. Materials and Methods: This prospective study was based on a population study with 1111 randomly selected participants (age range, 50-64 years) who underwent a medical evaluation that included chest computed tomography (CT). Among these, 125 participants with incidental nodules 5 mm or larger were included in this study, which added DTS in conjunction with the follow-up CT and was performed between March 2012 and October 2014. DTS images were assessed by four thoracic radiologists blinded to the true number of nodules in two separate sessions according to the 5-mm (125 participants) and 6-mm (55 participants) cut-off for follow-up of incidental nodules. Pulmonary nodules were directly marked on the images by the readers and graded regarding confidence of presence and recommendation for follow-up. Statistical analyses included jackknife free-response receiver operating characteristic, receiver operating characteristic, and Cohen k coefficient. Results: Overall detection rate ranges of CT-proven nodules 5 mm or larger and 6 mm or larger were, respectively, 49%58% and 48%-62%. Jackknife free-response receiver operating characteristics figure of merit for detection of CT-proven nodules 5 mm or larger and 6 mm or larger was 0.47 and 0.51, respectively, and area under the receiver operating characteristic curve regarding recommendation for follow-up was 0.62 and 0.65, respectively. Conclusion: Routine use of DTS would result in lower detection rates and reduced number of small nodules recommended for follow-up. (C) RSNA, 2018.
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- Meltzer, Carin, et al.
(författare)
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Nodule mimics in chest tomosynthesis
- 2017
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Ingår i: World Congress of Thoracic Imaging. June 18-21, 2017, Boston, Massachusetts.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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- Meltzer, Carin, et al.
(författare)
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Quantification of Pulmonary Pathology in Cystic Fibrosis-Comparison Between Digital Chest Tomosynthesis and Computed Tomography.
- 2021
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Ingår i: Radiation protection dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 195:3-4, s. 434-442
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Tidskriftsartikel (refereegranskat)abstract
- Digital tomosynthesis (DTS) is currently undergoing validation for potential clinical implications. The aim of this study was to investigate the potential for DTS as a low-dose alternative to computed tomography (CT) in imaging of pulmonary pathology in patients with cystic fibrosis (CF).DTS and CT were performed as part of the routine triannual follow-up in 31 CF patients. Extent of disease was quantified according to modality-specific scoring systems. Statistical analysis included Spearman's rank correlation coefficient (r) and Krippendorff's alpha (α).The median effective dose was 0.14 for DTS and 2.68 for CT. Intermodality correlation was very strong for total score and the subscores regarding bronchiectasis and bronchial wall-thickening (r=0.82-0.91, P<0.01). Interobserver reliability was high for total score, bronchiectasis and mucus plugging (α=0.83-0.93) in DTS.Chest tomosynthesis could be a low-dose alternative to CT in quantitative estimation of structural lung disease in CF.
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- Meltzer, Carin, et al.
(författare)
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Surveillance of small, solid pulmonary nodules at digital chest tomosynthesis: data from a cohort of the pilot Swedish CArdioPulmonary bioImage Study (SCAPIS)
- 2021
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Ingår i: Acta Radiologica. - : SAGE Publications. - 0284-1851 .- 1600-0455. ; 62:3, s. 348-359
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Tidskriftsartikel (refereegranskat)abstract
- Background Digital tomosynthesis (DTS) might be a low-dose/low-cost alternative to computed tomography (CT). Purpose To investigate DTS relative to CT for surveillance of incidental, solid pulmonary nodules. Material and Methods Recruited from a population study, 106 participants with indeterminate solid pulmonary nodules on CT underwent surveillance with concurrently performed CT and DTS. Nodule size on DTS was assessed by manual diameter measurements and semi-automatic nodule segmentations were independently performed on CT. Measurement agreement was analyzed according to Bland-Altman with 95% limits of agreement (LoA). Detection of nodule volume change > 25% by DTS in comparison to CT was evaluated with receiver operating characteristics (ROC). Results A total of 81 nodules (76%) were assessed as measurable on DTS by two independent observers. Inter- and intra-observer LoA regarding change in average diameter were +/- 2 mm. Calculation of relative volume change on DTS resulted in wide inter- and intra-observer LoA in the order of +/- 100% and +/- 50%. Comparing relative volume change between DTS and CT resulted in LoA of -58% to 67%. The area under the ROC curve regarding the ability of DTS to detect volumetric changes > 25% on CT was 0.58 (95% confidence interval [CI] = 0.40-0.76) and 0.50 (95% CI = 0.35-0.66) for the two observers. Conclusion The results of the present study show that measurement variability limits the agreement between DTS and CT regarding nodule size change for small solid nodules.
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- Meltzer, Carin, et al.
(författare)
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VISIBILITY OF STRUCTURES OF RELEVANCE FOR PATIENTS WITH CYSTIC FIBROSIS IN CHEST TOMOSYNTHESIS: INFLUENCE OF ANATOMICAL LOCATION AND OBSERVER EXPERIENCE
- 2016
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Ingår i: Radiation protection dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 169:1-4, s. 169-179
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Tidskriftsartikel (refereegranskat)abstract
- The aims of this study were to assess the visibility of pulmonary structures in patients with cystic fibrosis (CF) in digital tomosynthesis (DTS) using computed tomography (CT) as reference and to investigate the dependency on anatomical location and observer experience. Anatomical structures in predefined regions of CT images from 21 patients were identified. Three observers with different levels of experience rated the visibility of the structures in DTS by performing a head-to-head comparison with visibility in CT. Visibility of the structures in DTS was reported as equal to CT in 34 %, inferior in 52 % and superior in 14 % of the ratings. Central and peripheral lateral structures received higher visibility ratings compared with peripheral structures anteriorly, posteriorly and surrounding the diaphragm (p ≤ 0.001). Reported visibility was significantly higher for the most experienced observer (p ≤ 0.01). The results indicate that minor pathology can be difficult to visualise with DTS depending on location and observer experience. Central and peripheral lateral structures are generally well depicted.
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- Meltzer, Carin, et al.
(författare)
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Visibility of structures of relevance for patients with cystic fibrosis in chest tomosynthesis – influence of anatomical location and observer experience
- 2015
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Ingår i: Optimisation in X-ray and Molecular Imaging 2015 - the Fourth Malmö Conference on Medical Imaging, Gothenburg, Sweden, 28-30 May 2015.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Purpose: To assess visibility of pulmonary structures of relevance for patients with cystic fibrosis on digital tomosynthesis (DTS) images in comparison to computed tomography (CT) images and to investigate if visibility is affected by anatomical location and observer experience. Methods: Twenty-one patients with cystic fibrosis were examined by DTS and helical CT within 90 minutes. Tube voltage of both modalities was 120kV. Nominal slice thickness of the coronal section images of DTS was 5 mm and slice thickness of the transverse CT images was 1-1.25 mm. In each patient 30 pulmonary structures, primarily bronchiectasis, mucus plugging and vessels, were identified in predefined regions at four different anatomical levels of the CT examination, resulting in a total of 630 structures for head to head comparison between the modalities. Three observers, with varying experience both regarding DTS and patients with cystic fibrosis, independently evaluated visibility of the structures in DTS on a scale from 0 to 5 using the transverse CT images as reference and coronal CT images (thickness 4mm / increment 3mm) for anatomical guidance. The observers’ responses were analyzed using visual grading characteristics (VGC) analysis. Results: Visibility in DTS in comparison to CT was reported as equal in 34%, inferior in 52% and superior in 14 % of the structures. The visibility of structures in the central and peripheral lateral regions of the lungs received higher scores compared to the peripheral regions anteriorly, posteriorly and around the diaphragm (p≤0.001). There were no significant differences between the central regions of the different anatomical levels. The most experienced observer reported higher visibility scores than the two less experienced observers (p≤0.01). Conclusion: The results indicate that the perceived visibility of specific anatomical structures in DTS is generally inferior to CT and dependent on both anatomical location and observer experience.
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- Mirzai, Maral, et al.
(författare)
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The Effect of Dose Reduction on Overall Image Quality in Clinical Chest Tomosynthesis
- 2021
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Ingår i: Academic Radiology. - : Elsevier BV. - 1076-6332. ; 28:10, s. 289-296
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Tidskriftsartikel (refereegranskat)abstract
- Rationale and Objectives: To evaluate the effect of reduction in effective dose on the reproduction of anatomical structures in chest tomosynthesis (CTS). Materials and Methods: Twenty-four CTS examinations acquired at exposure settings resulting in an effective dose of 0.12 mSv for an average sized patient were included in the study. The examinations underwent simulated dose reduction to dose levels corresponding to 32%, 50%, and 70% of the original dose using a previously described and validated method. The image quality was evaluated by five thoracic radiologists who rated the fulfillment of specified image quality criteria in a visual grading study. The ratings for each image quality criterion in the dose-reduced images were compared to the corresponding ratings for the full-dose examinations using visual grading characteristics (VGC) analysis. The area under the resulting VGC curve (AUCVGC) provides a measure of the difference between the ratings, where an AUCVGC of 0.5 indicates no difference. Results: The dose reductions resulted in inferior reproduction of structures compared to the original dose level (AUCVGC <0.5). Structures in the central region of the lung obtained the lowest AUCVGC for each dose level whereas the reproduction of structures in the parenchyma was least affected by the dose reduction. Conclusion: Although previous studies have shown that dose reduction in CTS is possible without affecting the performance of certain clinical tasks, the reproduction of normal anatomical structures is significantly degraded even at small reductions. It is therefore important to consider the clinical purpose of the CTS examinations before deciding on a permanent dose reduction. © 2020 The Association of University Radiologists
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