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| 5. |
- Baumann, Stefan, et al.
(författare)
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Gender differences in the diagnostic performance of machine learning coronary CT angiography-derived fractional flow reserve -results from the MACHINE registry
- 2019
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Ingår i: European Journal of Radiology. - : ELSEVIER IRELAND LTD. - 0720-048X .- 1872-7727. ; 119
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: This study investigated the impact of gender differences on the diagnostic performance of machine-learning based coronary CT angiography (cCTA)-derived fractional flow reserve (CT-FFR mL ) for the detection of lesion-specific ischemia. Method: Five centers enrolled 351 patients (73.5% male) with 525 vessels in the MACHINE (Machine leArning Based CT angiograpHy derIved FFR: a Multi-ceNtEr) registry. CT-FFRML and invasive FFR amp;lt;= 0.80 were considered hemodynamically significant, whereas cCTA luminal stenosis amp;gt;= 50% was considered obstructive. The diagnostic performance to assess lesion-specific ischemia in both men and women was assessed on a per-vessel basis. Results: In total, 398 vessels in men and 127 vessels in women were included. Compared to invasive FFR, CT-FFRML reached a sensitivity, specificity, positive predictive value, and negative predictive value of 78% (95%CI 72-84), 79% (95%CI 73-84), 75% (95%CI 69-79), and 82% (95%CI: 76-86) in men vs. 75% (95%CI 58-88), 81 (95%CI 72-89), 61% (95%CI 50-72) and 89% (95%CI 82-94) in women, respectively. CT-FFRML showed no statistically significant difference in the area under the receiver-operating characteristic curve (AUC) in men vs. women (AUC: 0.83 [95%CI 0.79-0.87] vs. 0.83 [95%CI 0.75-0.89], p = 0.89). CT-FFRML was not superior to cCTA alone [AUC: 0.83 (95%CI: 0.75-0.89) vs. 0.74 (95%CI: 0.65-0.81), p = 0.12] in women, but showed a statistically significant improvement in men [0.83 (95%CI: 0.79-0.87) vs. 0.76 (95%CI: 0.71-0.80), p = 0.007]. Conclusions: Machine-learning based CT-FFR performs equally in men and women with superior diagnostic performance over cCTA alone for the detection of lesion-specific ischemia.
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| 6. |
- Björkman, Ann-Sofi, et al.
(författare)
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Spectral photon-counting CT: Image quality evaluation using a metal-containing bovine bone specimen
- 2023
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Ingår i: European Journal of Radiology. - : ELSEVIER IRELAND LTD. - 0720-048X .- 1872-7727. ; 168
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To find the optimal imaging parameters for a photon-counting detector CT (PCD-CT) and to compare it to an energy-integrating detector CT (EID-CT) in terms of image quality and metal artefact severity using a metal-containing bovine knee specimen. Methods: A bovine knee with a stainless-steel plate and screws was imaged in a whole-body research PCD-CT at 120 kV and 140 kV and in an EID dual-source CT (DSCT) at Sn150 kV and 80/Sn150 kV. PCD-CT virtual monoenergetic 72 and 150 keV images and EID-CT images processed with and without metal artefact reduction algorithms (iMAR) were compared. Four radiologists rated the visualisation of bony structures and metal artefact severity. The Friedman test and Wilcoxon signed-rank test with Bonferronis correction were used. P-values of <= 0.0001 were considered statistically significant. Distributions of HU values of regions of interest (ROIs) in artefact-affected areas were analysed.Results: PCD-CT 140 kV 150 keV images received the highest scores and were significantly better than EID-CT Sn150 kV images. PCD-CT 72 keV images were rated significantly lower than all the others. HU-value variation was larger in the 120 kV and the 72 keV images. The ROI analysis revealed no large difference between scanners regarding artefact severity.Conclusion: PCD-CT 140 kV 150 keV images of a metal-containing bovine knee specimen provided the best image quality. They were superior to, or as good as, the best EID-CT images; even without the presumed advantage of tin filter and metal artefact reduction algorithms. PCD-CT is a promising method for reducing metal artefacts.
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| 7. |
- Blomqvist, L., et al.
(författare)
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Limited evidence for the use of imaging to detect prostate cancer : a systematic review
- 2014
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Ingår i: European Journal of Radiology. - : Elsevier. - 0720-048X .- 1872-7727. ; 83:9, s. 1601-1606
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Forskningsöversikt (refereegranskat)abstract
- Objective: To assess the diagnostic accuracy of imaging technologies for detecting prostate cancer in patients with elevated PSA-values or suspected findings on clinical examination.Methods: The databases Medline, EMBASE, Cochrane, CRD HTA/DARE/NHS EED and EconLit were searched until June 2013. Pre-determined inclusion criteria were used to select full text articles. Risk of bias in individual studies was rated according to QUADAS or AMSTAR. Abstracts and full text articles were assessed independently by two reviewers. The performance of diagnostic imaging was compared with systematic biopsies (reference standard) and sensitivity and specificity were calculated.Results: The literature search yielded 5141 abstracts, which were reviewed by two independent reviewers. Of these 4852 were excluded since they did not meet the inclusion criteria. 288 articles were reviewed in full text for quality assessment. Six studies, three using MRI and three using transrectal ultrasound were included. All were rated as high risk of bias. Relevant studies on PET/CT were not identified.Conclusion: Despite clinical use, there is insufficient evidence regarding the accuracy of imaging technologies for detecting cancer in patients with suspected prostate cancer using TRUS guided systematic biopsies as reference standard. (C) 2014 Elsevier Ireland Ltd. All rights reserved.
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| 8. |
- Boita, Joana, et al.
(författare)
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Development and content validity evaluation of a candidate instrument to assess image quality in digital mammography : A mixed-method study
- 2021
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Ingår i: European Journal of Radiology. - : Elsevier BV. - 0720-048X. ; 134
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To develop a candidate instrument to assess image quality in digital mammography, by identifying clinically relevant features in images that are affected by lower image quality. Methods: Interviews with fifteen expert breast radiologists from five countries were conducted and analysed by using adapted directed content analysis. During these interviews, 45 mammographic cases, containing 44 lesions (30 cancers, 14 benign findings), and 5 normal cases, were shown with varying image quality. The interviews were performed to identify the structures from breast tissue and lesions relevant for image interpretation, and to investigate how image quality affected the visibility of those structures. The interview findings were used to develop tentative items, which were evaluated in terms of wording, understandability, and ambiguity with expert breast radiologists. The relevance of the tentative items was evaluated using the content validity index (CVI) and modified kappa index (k*). Results: Twelve content areas, representing the content of image quality in digital mammography, emerged from the interviews and were converted into 29 tentative items. Fourteen of these items demonstrated excellent CVI ≥ 0.78 (k* > 0.74), one showed good CVI < 0.78 (0.60 ≤ k* ≤ 0.74), while fourteen were of fair or poor CVI < 0.78 (k* ≤ 0.59). In total, nine items were deleted and five were revised or combined resulting in 18 items. Conclusions: By following a mixed-method methodology, a candidate instrument was developed that may be used to characterise the clinically-relevant impact that image quality variations can have on digital mammography.
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| 9. |
- Boita, Joana, et al.
(författare)
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Validation of a candidate instrument to assess image quality in digital mammography using ROC analysis
- 2021
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Ingår i: European Journal of Radiology. - : Elsevier BV. - 1872-7727 .- 0720-048X. ; 139
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Tidskriftsartikel (refereegranskat)abstract
- PurposeTo validate a candidate instrument, to be used by different professionals to assess image quality in digital mammography (DM), against detection performance results.MethodsA receiver operating characteristics (ROC) study was conducted to assess the detection performance in DM images with four different image quality levels due to different quality issues. Fourteen expert breast radiologists from five countries assessed a set of 80 DM cases, containing 60 lesions (40 cancers, 20 benign findings) and 20 normal cases. A visual grading analysis (VGA) study using a previously-described candidate instrument was conducted to evaluate a subset of 25 of the images used in the ROC study. Eight radiologists that had participated in the ROC study, and seven expert breast-imaging physicists, evaluated this subset. The VGA score (VGAS) and the ROC and visual grading characteristics (VGC) areas under the curve (AUCROC and AUCVGC) were compared.ResultsNo large differences in image quality among the four levels were detected by either ROC or VGA studies. However, the ranking of the four levels was consistent: level 1 (partial AUCROC: 0.070, VGAS: 6.77) performed better than levels 2 (0.066, 6.15), 3 (0.061, 5.82), and 4 (0.062, 5.37). Similarity between radiologists’ and physicists’ assessments was found (average VGAS difference of 10 %).ConclusionsThe results from the candidate instrument were found to correlate with those from ROC analysis, when used by either observer group. Therefore, it may be used by different professionals, such as radiologists, radiographers, and physicists, to assess clinically-relevant image quality variations in DM.
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| 10. |
- Booij, Ronald, et al.
(författare)
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Assessment of visibility of bone structures in the wrist using normal and half of the radiation dose with photon-counting detector CT
- 2023
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Ingår i: European Journal of Radiology. - : ELSEVIER IRELAND LTD. - 0720-048X .- 1872-7727. ; 159
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To quantitatively and qualitatively assess the visibility of bone structures in the wrist on photon-counting detector computed tomography (PCD-CT) images compared to state-of-the-art energy-integrating de-tector CT (EID-CT).Method: Four human cadaveric wrist specimens were scanned with EID-CT and PCD-CT at identical CTDIvolof 12.2 mGy and with 6.1 mGy (half dose PCD-CT). Axial images were reconstructed using the thinnest possible slice thickness, i.e. 0.4 mm on EID-CT and 0.2 mm on PCD-CT, with the largest image matrix size possible using reconstruction kernels optimized for bone (EID-CT: Ur68, PCD-CT: Br92). Quantitative evaluation was performed to determine contrast-noise ratio (CNR) of bone/ fat, cortical and trabecular sharpness. An observer study using visual grading characteristics (VGC) analysis was performed by six observers to assess the visibility of nutrient canals, trabecular architecture, cortical bone and the general image quality.Results: At equal dose, images obtained with PCD-CT had 39 +/- 6 % lower CNR (p = 0.001), 71 +/- 57 % higher trabecular sharpness in the radius (p = 0.02) and 42 +/- 8 % (p < 0.05) sharper cortical edges than those obtained with EID-CT. This was confirmed by VGC analysis showing a superior visibility of nutrient canals, trabeculae and cortical bone area under the curve (AUC) > 0.89) for PCD-CT, even at half dose.Conclusions: Despite a lower CNR and increased noise, the trabecular and cortical sharpness were twofold higher with PCD-CT. Visual grading analysis demonstrated superior visibility of cortical bone, trabeculae, nutrient canals and an overall improved image quality with PCD-CT over EID-CT. At half dose, PCD-CT also yielded superior image quality, both in quantitative measures and as evaluated by radiologists.
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| 11. |
- Bornefalk, Hans, et al.
(författare)
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Single-shot dual-energy subtraction mammography with electronic spectrum splitting : Feasibility
- 2006
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Ingår i: European Journal of Radiology. - : Elsevier BV. - 0720-048X .- 1872-7727. ; 60:2, s. 275-278
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Tidskriftsartikel (refereegranskat)abstract
- We present a single-shot dual-energy subtraction mammography technique using an energy sensitive photon counting detector. An electronic threshold near the middle of the X-ray spectrum discriminates between high- and low-energy photons, and allows the simultaneous acquisition of high- and low-energy images which can be combined to suppress anatomical clutter. By setting the electronic threshold close to 33.2 keV (the k-edge of iodine) the system is optimized for dual-energy contrast-enhanced imaging of breast tumors. This method eliminates the need for separate exposures which might otherwise lead to motion artifacts. The method is illustrated in phantom images.
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| 14. |
- Diaz, Sandra, et al.
(författare)
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Validity of apparent diffusion coefficient hyperpolarized He-3-MRI using MSCT and pulmonary function tests as references
- 2009
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Ingår i: European Journal of Radiology. - : Elsevier BV. - 1872-7727 .- 0720-048X. ; 71:2, s. 257-263
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To compare apparent diffusion coefficient (ADC) measurements from hyperpolarized (HP) helium (He-3)-magnetic resonance imaging (MRI) with quantitative data from multislice Computed Tomography (CT) (MSCT) of the whole lungs and pulmonary function tests (PFT). Materials and methods: Twenty-seven subjects, 22 with established emphysema and 5 with preclinical emphysema defined by PFT criteria, were examined with Hp He-3-MRI and MSCT. Mean age was 55 (+/- 12) years, 18 female and 9 male. Mean ADC from He-3-MRI was compared with emphysema index (EI), 15th percentile and mean lung density (MLD) values from MSCT. Both mean ADC and MSCT data were compared to PFT, especially percent of predicted diffusing capacity of carbon monoxide (%predicted DLCO), using Pearson's correlation test. Results: Mean ADC and standard deviation values were 0.392 +/- 0.119 cm(2)/s for the established emphysema group and 0.216 +/- 0.046 for the pre-clinical emphysema group. MSCT values for the established emphysema group and pre-clinical emphysema group were: EI (%) 11 +/- 12 and 0.4 +/- 0.6, respectively; 15th percentile (Hounsfield Units (HU)), -956 +/- 25 and -933 +/- 13, respectively and MLD (HU) -877 +/- 20 and -863 +/- 15, respectively. Correlations between mean ADC and El and 15th percentile were both r=0.90 and for MLD r=0.59. There was higher correlation between mean ADC and %predicted DLCO (r=0.90) than between El and %predicted DLCO (r=0.76). Conclusion: Hp He-3-MRI correlates well with density measurements from MSCT and agrees better than MSCT with %predicted DLCO which is the PFT most related to emphysema. (C) 2008 Elsevier Ireland Ltd. All rights reserved.
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| 15. |
- Dustler, Magnus, et al.
(författare)
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High-attenuation artifact reduction in breast tomosynthesis using a novel reconstruction algorithm
- 2019
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Ingår i: European Journal of Radiology. - : Elsevier BV. - 0720-048X. ; 116, s. 21-26
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To assess the effect on reducing the out-of-plane artifacts from metal objects in breast tomosynthesis (BT)using a novel artifact-reducing reconstruction algorithm in specimen radiography. Methods and Materials: The study was approved by the Regional Ethical Review Board. BT images of 18 partial- and whole mastectomy specimens from women with breast cancer were acquired before and after a needle was inserted close to the lesion. The images were reconstructed using both a standard reconstruction algorithm, and a novel algorithm; the latter uses pre-segmentation to remove highly attenuating artifact-inducing objects from projection images before reconstruction. Images were separately reconstructed with and without segmentation, and combined into an artifact-reduced reconstruction. Standard and artifact-reduced BT-algorithms were compared visually and quantitatively using clinical images of mastectomy specimens and a physical anthropomorphic phantom. Six readers independently assessed the visibility of the lesion with and without artifact-reduction in a side-by-side comparison. A quantitative analysis was performed, comparing the signal-difference to background ratio (SDBR)and artifact spread function (ASF)between the two reconstruction methods. Results: The magnitude of out-of-plane artifacts was clearly reduced with the novel reconstruction compared to BT-images without artifact reduction. Lesion masking by artifacts was largely averted; tumour visibility was comparable to standard BT images without a needle. In 76 ± 8% (standard deviation)of cases overall, readers could confidently state needle location. The same figure was 94 ± 6% for whole mastectomy cases, compared to 62 ± 17% for partial mastectomies. With metal artifact reduction, SDBR increased by 97% in the phantom, and by 69% in the mastectomies. The artifact spread function was substantially narrower. Conclusion: Artifact reduction in BT using a novel reconstruction method enables qualitatively and quantitatively improved clinical use of BT when metal artifacts can be a limiting factor such as in tomosynthesis-guided biopsy.
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| 16. |
- Ekholm, S. E., et al.
(författare)
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MRI staging using gadodiamide for soft-tissue tumors of the head and neck region. Results from a phase II trial and a 5-year clinical follow-up
- 2001
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Ingår i: Eur J Radiol. - 0720-048X. ; 39:3, s. 168-75
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Tidskriftsartikel (refereegranskat)abstract
- In order to document the safety, tolerability and efficacy of gadodiamide outside CNS, an open, non-drug comparative study was performed in patients with tumors of the head and neck region. Fifty adult patients were included and 48 patients received the contrast medium. The examinations were performed on a 1.5 T imager using transverse, non-enhanced T1- and PD-/T2-weighted conventional spin-echo sequences, followed by a contrast-enhanced transverse T1-weighted sequence. Post-contrast images provided more diagnostic information compared to unenhanced images in 33 of 48 patients (69%). This information was of significant help in four and of moderate help in 14 cases. Post-contrast images compared to non-enhanced T1-weighted showed improvement in lesion delineation for 29 of the 43 patients where a lesion was observed. Only in two patients was the diagnostic information lower post-contrast. A comparison between all pre-contrast images versus contrast medium enhanced showed post-contrast images to give more diagnostic information in 14 and less in nine patients. No patient experienced discomfort in relation to gadodiamide injection. Only one adverse event occurred which was described as thirst, being of moderate intensity. The 5-year clinical outcome was analyzed and compared with the pre-operative staging. The case-books of all patients were reviewed and in 44 patients all information could be found. Of those, 18 were still alive, one with active disease (AAD) and 17 with no evidence of disease (NED). Two of those four patients, where information was incomplete, showed NED and two had died. This trial showed that contrast-enhancement using gadodiamide for evaluation of soft tissue tumors in the head and neck region was safe and provided statistically significant more diagnostic information compared with unenhanced images. MRI, when compared with palpation/inspection, changed tumor staging in approximately 30% of all cases.
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| 17. |
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| 18. |
- Eriksson, Anders, et al.
(författare)
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Diagnostic accuracy of postmortem imaging vs autopsy : a systematic review
- 2017
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Ingår i: European Journal of Radiology. - : ELSEVIER IRELAND LTD. - 0720-048X .- 1872-7727. ; 89, s. 249-269
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Forskningsöversikt (refereegranskat)abstract
- Background Postmortem imaging has been used for more than a century as a complement to medico-legal autopsies. The technique has also emerged as a possible alternative to compensate for the continuous decline in the number of clinical autopsies. To evaluate the diagnostic accuracy of postmortem imaging for various types of findings, we performed this systematic literature review. Data sources The literature search was performed in the databases PubMed, Embase and Cochrane Library through January 7, 2015. Relevant publications were assessed for risk of bias using the QUADAS tool and were classified as low, moderate or high risk of bias according to pre-defined criteria. Autopsy and/or histopathology were used as reference standard. Findings The search generated 2600 abstracts, of which 340 were assessed as possibly relevant and read in full-text. After further evaluation 71 studies were finally included, of which 49 were assessed as having high risk of bias and 22 as moderate risk of bias. Due to considerable heterogeneity - in populations, techniques, analyses and reporting - of included studies it was impossible to combine data to get a summary estimate of the diagnostic accuracy of the various findings. Individual studies indicate, however, that imaging techniques might be useful for determining organ weights, and that the techniques seem superior to autopsy for detecting gas Conclusions and Implications In general, based on the current scientific literature, it was not possible to determine the diagnostic accuracy of postmortem imaging and its usefulness in conjunction with, or as an alternative to autopsy. To correctly determine the usefulness of postmortem imaging, future studies need improved planning, improved methodological quality and larger materials, preferentially obtained from multi-center studies.
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| 19. |
- Fennessy, F. M., et al.
(författare)
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Quantitative diffusion MRI in prostate cancer: Image quality, what we can measure and how it improves clinical assessment
- 2023
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Ingår i: European Journal of Radiology. - 0720-048X. ; 167
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Forskningsöversikt (refereegranskat)abstract
- Diffusion-weighted imaging is a dependable method for detection of clinically significant prostate cancer. In prostate tissue, there are several compartments that can be distinguished from each other, based on different water diffusion decay signals observed. Alterations in cell architecture, such as a relative increase in tumor infiltration and decrease in stroma, will influence the observed diffusion signal in a voxel due to impeded random motion of water molecules. The amount of restricted diffusion can be assessed quantitatively by measuring the apparent diffusion coefficient (ADC) value. This is traditionally calculated using a monoexponential decay formula represented by the slope of a line produced between the logarithm of signal intensity decay plotted against selected b-values. However, the choice and number of b-values and their distribution, has a significant effect on the measured ADC values. There have been many models that attempt to use higher-order functions to better describe the observed diffusion signal decay, requiring an increased number and range of b-values. While ADC can probe heterogeneity on a macroscopic level, there is a need to optimize advanced diffusion techniques to better interrogate prostate tissue microstructure. This could be of benefit in clinical challenges such as identifying sparse tumors in normal prostate tissue or better defining tumor margins. This paper reviews the principles of diffusion MRI and novel higher order diffusion signal analysis techniques to improve the detection of prostate cancer.
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| 20. |
- Fredäng Kämmerling, Nina, et al.
(författare)
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A comparative study of image quality and diagnostic confidence in diagnosis and follow-up of scaphoid fractures using photon-counting detector CT and energy-integrating detector CT
- 2024
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Ingår i: European Journal of Radiology. - : ELSEVIER IRELAND LTD. - 0720-048X .- 1872-7727. ; 173
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Scaphoid fractures in patients and assessment of healing using PCD-CT have, as far as we know, not yet been studied. Therefore, the aim was to compare photon counting detector CT (PCD-CT) with energy integrating detector CT (EID-CT) in terms of fracture visibility and evaluation of fracture healing. Method: Eight patients with scaphoid fracture were examined with EID-CT and PCD-CT within the first week posttrauma, and with additional scans at 4, 6 and 8 weeks. Our clinical protocol for wrist examination with EID-CT was used (CTDIvol 3.1 +/- 0.1 mGy, UHR kernel Ur77). For PCD-CT matched radiation dose, reconstruction kernel Br89. Quantitative analyses of noise, CNR, trabecular and cortical sharpness, and bone volume fraction were conducted. Five radiologists evaluated the images for fracture visibility, fracture gap consolidation and image quality, and rated their confidence in the diagnosis. Results: The trabecular and cortical sharpness were superior in images obtained with PCD-CT compared with EIDCT. A successive reduction in trabecular bone volume fraction during the immobilized periods was found with both systems. Despite higher noise and lower CNR with PCD-CT, radiologists rated the image quality of PCD-CT as superior. The visibility of the fracture line within 1 -week post -trauma was rated higher with PCD-CT as was diagnostic confidence, but the subsequent assessments of fracture gap consolidation during healing process and the confidence in diagnosis were found equivalent between both systems. Conclusion: PCD-CT offers superior visibility of bone microstructure compared with EID-CT. The evaluation of fracture healing and confidence in diagnosis were rated equally with both systems, but the radiologists found primary fracture visibility and overall image quality superior with PCD-CT.
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| 21. |
- Grankvist, J, et al.
(författare)
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MRI and PET/CT of patients with bone metastases from breast carcinoma
- 2012
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Ingår i: European Journal of Radiology. - : Elsevier BV. - 0720-048X .- 1872-7727. ; 81:1, s. e13-e18
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Tidskriftsartikel (refereegranskat)abstract
- 3.0Tesla magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) was compared with combined 18F-fluorodeoxyglucose positron emission tomography and computed tomography (PET/CT) in patients with suspected bone metastases from breast cancer. A prospective clinical study was performed in 13 female breast cancer patients (mean age 61years; range 45-85 years). The spine was imaged in the sagittal plane with T1-weighted (T1), short tau inversion recovery (STIR), and T2-weighted fat-saturated (T2) sequences. The pelvis was imaged similarly in the coronal plane. Axial DWI was performed from the skull base to the mid-thigh. MRI and PET/CT were performed in all patients at a maximum interval of 10 working days and at least 14 days after chemotherapy. MRI was reviewed by two radiologists, and their consensus on potential metastases in 27 predefined locations was recorded. The predefined locations were the vertebral bodies (24), the left (1) and right (1) pelvic bones, and the sacral bone (1). The PET/CT was reviewed by a radiologists and a nuclear medicine physician. MRI detected 59 of the 60 active metastases found with our gold standard modality PET/CT. T1 had the highest sensitivity (98%) but rather low specificity (77%), but with the addition of STIR and DWI, the specificity increased to 95%. The additional metastases detected with MRI most likely represented postherapeutic residual scars without active tumour. In conclusion, 3.0Tesla MRI with T1, STIR, and DWI is useful for the clinical evaluation of bone metastases from breast cancer and compares well to PET/CT.
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| 22. |
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| 23. |
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| 24. |
- Helms, Gunther
(författare)
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The principles of quantification applied to in vivo proton MR spectroscopy
- 2008
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Ingår i: European Journal of Radiology. - : Elsevier BV. - 1872-7727 .- 0720-048X. ; 67:2, s. 218-229
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Forskningsöversikt (refereegranskat)abstract
- Following the identification of metabolite signals in the in vivo MR spectrum, quantification is the procedure to estimate numerical values of their concentrations. The two essential steps are discussed in detail: analysis by fitting a model of prior knowledge, that is, the decomposition of the spectrum into the signals of singular metabolites; then, normalization of these signals to yield concentration estimates. Special attention is given to using the in vivo water signal as internal reference.
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| 25. |
- Hennings, Joakim, et al.
(författare)
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Computed tomography, magnetic resonance imaging and 11C-metomidate positron emission tomography for evaluation of adrenal incidentalomas
- 2009
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Ingår i: European Journal of Radiology. - : Elsevier BV. - 0720-048X .- 1872-7727. ; 69:2, s. 314-23
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Given the higher sensitivity of modern computed tomography (CT) scanners, adrenal incidentalomas are being discovered increasingly often. This implies a growing quantitative diagnostic and clinical problem. CT and/or magnetic resonance imaging (MRI) and usually thorough hormonal testing are routinely used to determine the origin of these lesions. Recently, positron emission tomography (PET) using the tracer (11)C-metomidate (MTO) has been established as an alternative diagnostic method with high sensitivity for identifying adrenocortical lesions. The aim of this study was to evaluate the clinical use and value of MTO-PET compared to CT and MRI in the characterisation and work-up of adrenal incidentalomas. METHODS: Initially, we retrospectively evaluated 20 adrenal incidentalomas in patients who had undergone CT, MRI and MTO-PET and from whom we had either histopathological diagnosis or clinical follow-up data. After this analysis we conducted a prospective study in order to compare the imaging modalities. In the latter study, 24 incidentalomas were imaged by CT, MRI and MTO-PET and the results were correlated to those from histopathology (n=8) and clinical diagnosis after follow-up (n=16). RESULTS: In the retrospective analysis, MRI and especially MTO-PET, correlated well to histopathology and clinical diagnosis after follow-up, whereas specificity with CT was low. This was possibly due to the presence of several haematomas/fibrosis which were misdiagnosed as adrenocortical adenomas. In the prospective cohort, sensitivity and specificity with CT were 0.71 and 1.0, respectively, and further characterisation by MRI increased these values to 0.86 and 1.0, whereas maximum sensitivity and specificity were reached when MTO-PET was added. CONCLUSION: The diagnosis of an adrenocortical adenoma may be established by CT in most patients and by MRI in an additional number. For the few remaining patients needing further characterisation, MTO-PET is advantageous as an additional imaging modality.
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| 26. |
- Hjelmgren, Ola, et al.
(författare)
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A study of plaque vascularization and inflammation using quantitative contrast-enhanced US and PET/CT
- 2014
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Ingår i: European Journal of Radiology. - : Elsevier BV. - 0720-048X .- 1872-7727. ; 83:7, s. 1184-1189
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Tidskriftsartikel (refereegranskat)abstract
- Background: Contrast-enhanced ultrasound (CEUS) is an in vivo methodology to quantify carotid plaque vascularization. Increased metabolism in plaques, measured as FDG uptake in PET/CT examination, has been associated with markers of inflammation in histological samples. In this study, we tested the association between FDG uptake and vascularization measured by CEUS to assess whether CEUS can be used as an in vivo marker of plaque vulnerability. Methods: After informed consent, subjects aged >60 years with carotid plaque height exceeding 2.5 mm were recruited. CEUS was performed and analyzed using earlier described protocol and software, Contrast Quantification Program, which calculates the fraction of the plaque being contrast positive (CQP value). PET/CT examination was performed within 3 months of CEUS (median time 7 days). PET/CT images were acquired 90 min after FDG injection (2.7 MBq/kg). FDG uptake was measured as tissue background index (TBI), calculated using Spearman's rho as mean standard uptake value (SUV) of the plaque divided by mean Shy in the jugular vein (mean of 7 measuring points). Local ethics committee approved the study. Results: We recruited 13 subjects (5 women) with a mean age of 71 years, 6 had a history of stroke or TIA, 1 had a history of ipsilateral stroke. CQP values showed a significant, positive correlation with TBI of carotid plaques, r= 0.67, p <0.02. Conclusions: Plaque vascularization measured by CEUS correlates positively with FDG uptake measured by PET/CT in humans. This indicates an association between vascularization and inflammation and/or hypoxia, supporting the use of CEUS as a non-invasive method to detect plaque vulnerability. (C) 2014 Elsevier Ireland Ltd. All rights reserved.
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| 27. |
- Holen, Åsne Sørlien, et al.
(författare)
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Early screening outcomes before, during, and after a randomized controlled trial with digital breast tomosynthesis
- 2023
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Ingår i: European Journal of Radiology. - 0720-048X. ; 167
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To describe and compare early screening outcomes before, during and after a randomized controlled trial with digital breast tomosynthesis (DBT) including synthetic 2D mammography versus standard digital mammography (DM) (To-Be 1) and a follow-up cohort study using DBT (To-Be 2). Methods: Retrospective results of 125,020 screening examinations from four consecutive screening rounds performed in 2014–2021 were described and compared for pre-To-Be 1 (DM), To-Be 1 (DM or DBT), To-Be 2 (DBT), and post-To-Be 2 (DM) cohorts. Descriptive analyses of rates of recall, biopsy, screen-detected and interval cancer, distribution of histopathologic tumor characteristics and time spent on image interpretation and consensus were presented for the four rounds including five cohorts, one cohort in each screening round except for the To-Be 1 trail, which included a DBT and a DM cohort. Odds ratios (OR) with 95% CIs was calculated for recall and cancer detection rates. Results: Rate of screen-detected cancer was 0.90% for women screened with DBT in To-Be 2 and 0.64% for DM in pre-To-Be 1. The rates did not differ for the To-Be 1 DM (0.61%), To-Be 1 DBT (0.66%) and post-To-Be 2 DM (0.67%) cohorts. The interval cancer rates ranged between 0.13% and 0.20%. The distribution of histopathologic tumor characteristics did not differ between the cohorts. Conclusions: Screening all women with DBT following a randomized controlled trial in an organized, population-based screening program showed a temporary increase in the rate of screen-detected cancer.
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| 28. |
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| 29. |
- Kanis, John A, et al.
(författare)
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Assessment of fracture risk
- 2009
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Ingår i: European Journal of Radiology. - : Elsevier BV. - 0720-048X .- 1872-7727. ; 71:3, s. 392-7
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Tidskriftsartikel (refereegranskat)abstract
- Fractures are a common complication of osteoporosis. Although osteoporosis is defined by bone mineral density at the femoral neck, other sites and validated techniques can be used for fracture prediction. Several clinical risk factors contribute to fracture risk independently of BMD. These include age, prior fragility fracture, smoking, excess alcohol, family history of hip fracture, rheumatoid arthritis and the use of oral glucocorticoids. These risk factors in conjunction with BMD can be integrated to provide estimates of fracture probability using the FRAX tool. Fracture probability rather than BMD alone can be used to fashion strategies for the assessment and treatment of osteoporosis.
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| 30. |
- Karlsson, Anders, et al.
(författare)
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The accuracy of incremental pre-operative breast MRI findings - Concordance with histopathology in the Swedish randomized multicenter POMB trial
- 2019
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Ingår i: European Journal of Radiology. - : ELSEVIER IRELAND LTD. - 0720-048X .- 1872-7727. ; 114, s. 185-191
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The Pre-Operative MRI of the Breast (POMB) trial was a randomized, prospective, multicenter trial evaluating the impact of pre-operative breast MRI on treatment regimens and short-term surgical outcomes in women up to 56 years of age with breast cancer. The purpose of this study was to evaluate the performance of pre-operative breast MRI in the POMB trial with respect to incremental MRI findings - over conventional breast imaging methods - and their concordance with histopathology.Patients and methods: Two-hundred and ten patients (n = 210) participating in the POMB trial underwent preoperative breast MRI at two Swedish breast units. Positive predictive values (PPV) for the incremental MRI findings were calculated for three subgroups of patients with: 1. alteration/alterations of treatment plan; 2. no alteration of treatment plan; and, 3. MRI-related conversion from BCS to mastectomy. Area under the receiver operating characteristic curve (AUC) was calculated using in-breast BI-RADS based ratings for the whole MRI group.Results: After exclusions a total number of 99 incremental findings in 78 patients were eligible for statistical analysis resulting in a PPV = 74%: (95% CI 60-84%) in 39 patients with MRI related alterations of initial treatment plans and 27%: (95% CI 14-44%) in 39 patients without. Positive predictive values of incremental findings decisive for specific treatment alteration/s were 83% (95% CI 68-92%) in patients with any alteration of initial treatment plans and 91% (95% CI 70-98%) for patients (n = 20/22) with conversion from breast conserving surgery to mastectomy. The empirical AUC for the incremental findings in the whole MRI group was 85% (95% CI 78-91%).Conclusion: Breast MRI, performed and evaluated together with conventional breast imaging methods can provide relevant information at a high degree of accuracy in the pre-operative setting.
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| 31. |
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| 32. |
- Kataria, Bharti, 1955-, et al.
(författare)
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Assessment of image quality in abdominal computed tomography : Effect of model-based iterative reconstruction, multi-planar reconstruction and slice thickness on potential dose reduction
- 2020
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Ingår i: European Journal of Radiology. - : Elsevier Ireland Ltd. - 0720-048X .- 1872-7727. ; 122
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To determine the effect of tube load, model-based iterative reconstruction (MBIR) strength and slice thickness in abdominal CT using visual comparison of multi-planar reconstruction images. Method: Five image criteria were assessed independently by four radiologists on two data sets at 42- and 98-mAs tube loads for 25 patients examined on a 192-slice dual-source CT scanner. Effect of tube load, MBIR strength, slice thickness and potential dose reduction was estimated with Visual Grading Regression (VGR). Objective image quality was determined by measuring noise (SD), contrast-to-noise (CNR) ratio and noise-power spectra (NPS). Results: Comparing 42- and 98-mAs tube loads, improved image quality was observed as a strong effect of log tube load regardless of MBIR strength (p < 0.001). Comparing strength 5 to 3, better image quality was obtained for two criteria (p < 0.01), but inferior for liver parenchyma and overall image quality. Image quality was significantly better for slice thicknesses of 2mm and 3mm compared to 1mm, with potential dose reductions between 24%-41%. As expected, with decrease in slice thickness and algorithm strength, the noise power and SD (HU-values) increased, while the CNR decreased. Conclusion: Increasing slice thickness from 1 mm to 2 mm or 3 mm allows for a possible dose reduction. MBIR strength 5 shows improved image quality for three out of five criteria for 1 mm slice thickness. Increasing MBIR strength from 3 to 5 has diverse effects on image quality. Our findings do not support a general recommendation to replace strength 3 by strength 5 in clinical abdominal CT protocols. However, strength 5 may be used in task-based protocols.
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| 33. |
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| 34. |
- Krause, Johan, et al.
(författare)
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Ultrasonography findings and tumour quantification in patients with pseudomyxoma peritonei
- 2012
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Ingår i: European Journal of Radiology. - : Elsevier BV. - 0720-048X .- 1872-7727. ; 81:4, s. 648-651
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Tidskriftsartikel (refereegranskat)abstract
- Pseudomyxoma peritonei (PMP) is a disease with various clinical presentations and the diagnostic value of ultrasonography (US) is under investigated. The purpose of this study was to identify the most common US finding in PMP and to investigate US sensitivity, specificity, positive and negative predictive value in quantifying tumour burden in different abdomino-pelvic regions in PMP patients. Between February 2006 and December 2008, 54 patients were treated with cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) due to PMP. The results from preoperative US examination with and without intravenously administrated contrast (SonoVue) were compared to surgical findings. The mean US peritoneal cancer index (PCI) was 6 (range 0-25) and the surgical PCI was 18 (range 3-27) p<0.0001. The histo-pathological subtypes did not influence the US findings. Ascites, bowel loops adhesions and omental cake were mostly visualised correctly by US. The sensitivity of US in quantification of tumour nodules was 91.5% (range 74-100%) and specificity was 33.8% (range 18-55%). The positive predictive value of US examination in PMP was 22% (range 11-44%) and the negative predictive value was 93% (range 77-100%). US can detect the most common PMP findings (ascites and omental cake). The sensitivity of US to quantify PMP tumour burden in different abdominio-pelvic region was relatively high, however, this imaging tool had low specificity.
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| 35. |
- Kvist, Ola, et al.
(författare)
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DTI assessment of the maturing growth plate of the knee in adolescents and young adults
- 2023
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Ingår i: European Journal of Radiology. - : Elsevier. - 0720-048X .- 1872-7727. ; 162
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To assess the growth plates of the knee in a healthy population of young adults and adolescents using DTI, and to correlate the findings with chronological age and skeletal maturation.METHODS: A prospective, cross-sectional study to assess the tibial and femoral growth plates with DTI in 155 healthy volunteers aged between 14.0 and 21 years old. Echo-planar DTI with 15 directions and b value of 0 and 600 s/mm2 was performed on a 3 T whole-body scanner.RESULTS: A relationship was observed between chronological age and most DTI metrics (fractional anisotropy, mean diffusivity, and radial diffusivity), tract length and volume. (No significant relationship could be seen for axonal diffusivity and tract length.) Subdivision according to skeletal maturation showed the greatest tract lengths and volumes seen in stage 4b and not 4a. The intra-observer agreement was significant (P = 0.01) for all the measured variables, but agreement varied (femur 0.53 - 0.98; tibia 0.58 - 0.98). Spearman's correlation showed a significant correlation for age (P = 0.05; P = 0.01) as well as for the fractional anisotropy value within all variables in both femur and tibia. Tract number and volume had a similar correlation with most variables, especially the DTI metrics, and would seem to be interchangeable.CONCLUSION: The current study indicates that DTI metrics could be a tool to assess the skeletal maturation process of the growth plate and its activity. Tractography seems promising to assess the activity of the growth plate in a younger population but must be used with caution in the more mature growth plate.
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| 36. |
- Kämmerling, Nina, et al.
(författare)
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Assessment of image quality in photon-counting detector computed tomography of the wrist - An ex vivo study
- 2022
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Ingår i: European Journal of Radiology. - : Elsevier Ireland Ltd. - 0720-048X .- 1872-7727. ; 154
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The aim of this study was to evaluate the effect of reconstruction parameters on image quality in wrist imaging using photon-counting detector CT (PCD-CT) and to compare the results with images from an energyintegrating detector CT (EID-CT). Methods: Twelve cadaveric wrist specimens were examined using a prototype PCD-CT and a clinical EID-CT using similar radiation dose. Reconstruction parameters were matched between scanners. Also, sharper reconstruction kernels, a larger matrix size, and smaller slice thicknesses were evaluated for PCD-CT. Image noise, contrast-tonoise ratio (CNR) and image sharpness in trabecular structures were quantitatively measured. Image quality with respect to the visibility of cortical and trabecular bone structures was assessed by six radiologists using visual grading methods.Results: Images obtained with PCD-CT had lower noise (42.6 +/- 3.9 HU vs 75.1 +/- 6.3 HU), higher CNR (38.9 +/- 4.5 vs 19.0 +/- 2.4) and higher trabecular sharpness (63.5 +/- 6.0 vs 53.7 +/- 8.5) than those obtained with EID-CT using similar scan and reconstruction parameters (p < 0.001). The image sharpness in trabecular structures was further improved by using sharper kernels, despite higher noise levels. Radiologists had a strong preference for PCD-CT images both in terms of spatial resolution and suitability for bone imaging. Visual grading analysis showed an improved visibility of cortical bone, trabeculae and nutritive canals (p < 0.005).Conclusion: PCD-CT offers improved image quality regarding bone structures in the wrist relative to EID-CT systems, particularly when sharper reconstruction kernels, smaller slice thickness and a larger image matrix size are used.
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| 37. |
- Lindgren Belal, Sarah, et al.
(författare)
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Deep learning for segmentation of 49 selected bones in CT scans: First step in automated PET/CT-based 3D quantification of skeletal metastases
- 2019
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Ingår i: European Journal of Radiology. - : Elsevier BV. - 0720-048X .- 1872-7727. ; 113, s. 89-95
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The aim of this study was to develop a deep learning-based method for segmentation of bones in CT scans and test its accuracy compared to manual delineation, as a first step in the creation of an automated PET/CT-based method for quantifying skeletal tumour burden. Methods: Convolutional neural networks (CNNs) were trained to segment 49 bones using manual segmentations from 100 CT scans. After training, the CNN-based segmentation method was tested on 46 patients with prostate cancer, who had undergone 18 F-choline-PET/CT and 18 F-NaF PET/CT less than three weeks apart. Bone volumes were calculated from the segmentations. The network's performance was compared with manual segmentations of five bones made by an experienced physician. Accuracy of the spatial overlap between automated CNN-based and manual segmentations of these five bones was assessed using the Sørensen-Dice index (SDI). Reproducibility was evaluated applying the Bland-Altman method. Results: The median (SD) volumes of the five selected bones were by CNN and manual segmentation: Th7 41 (3.8) and 36 (5.1), L3 76 (13) and 75 (9.2), sacrum 284 (40) and 283 (26), 7th rib 33 (3.9) and 31 (4.8), sternum 80 (11) and 72 (9.2), respectively. Median SDIs were 0.86 (Th7), 0.85 (L3), 0.88 (sacrum), 0.84 (7th rib) and 0.83 (sternum). The intraobserver volume difference was less with CNN-based than manual approach: Th7 2% and 14%, L3 7% and 8%, sacrum 1% and 3%, 7th rib 1% and 6%, sternum 3% and 5%, respectively. The average volume difference measured as ratio volume difference/mean volume between the two CNN-based segmentations was 5–6% for the vertebral column and ribs and ≤3% for other bones. Conclusion: The new deep learning-based method for automated segmentation of bones in CT scans provided highly accurate bone volumes in a fast and automated way and, thus, appears to be a valuable first step in the development of a clinical useful processing procedure providing reliable skeletal segmentation as a key part of quantification of skeletal metastases.
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| 38. |
- Lofthag-Hansen, Sara, 1956, et al.
(författare)
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Evaluation of subjective image quality in relation to diagnostic task for cone beam computed tomography with different fields of view.
- 2011
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Ingår i: European journal of radiology. - : Elsevier BV. - 1872-7727 .- 0720-048X. ; 80:2, s. 483-488
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: To evaluate subjective image quality for two diagnostic tasks, periapical diagnosis and implant planning, for cone beam computed tomography (CBCT) using different exposure parameters and fields of view (FOVs). MATERIALS AND METHODS: Examinations were performed in posterior part of the jaws on a skull phantom with 3D Accuitomo (FOV 3cm×4cm) and 3D Accuitomo FPD (FOVs 4cm×4cm and 6cm×6cm). All combinations of 60, 65, 70, 75, 80kV and 2, 4, 6, 8, 10mA with a rotation of 180° and 360° were used. Dose-area product (DAP) value was determined for each combination. The images were presented, displaying the object in axial, cross-sectional and sagittal views, without scanning data in a random order for each FOV and jaw. Seven observers assessed image quality on a six-point rating scale. RESULTS: Intra-observer agreement was good (κ(w)=0.76) and inter-observer agreement moderate (κ(w)=0.52). Stepwise logistic regression showed kV, mA and diagnostic task to be the most important variables. Periapical diagnosis, regardless jaw, required higher exposure parameters compared to implant planning. Implant planning in the lower jaw required higher exposure parameters compared to upper jaw. Overall ranking of FOVs gave 4cm×4cm, 6cm×6cm followed by 3cm×4cm. CONCLUSIONS: This study has shown that exposure parameters should be adjusted according to diagnostic task. For this particular CBCT brand a rotation of 180° gave good subjective image quality, hence a substantial dose reduction can be achieved without loss of diagnostic information.
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| 39. |
- Loizou, L., et al.
(författare)
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Radiological assessment of local resectability status in patients with pancreatic cancer: Interreader agreement and reader performance in two different classification systems
- 2018
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Ingår i: European Journal of Radiology. - : Elsevier BV. - 0720-048X .- 1872-7727. ; 106, s. 69-76
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To assess the interreader agreement and reader performance in the evaluation of patients with pancreatic cancer (PC) in two classification systems of local resectability status prior to initiation of therapy, namely the National Comprehensive Cancer Network (NCCN) and Karolinska classification system (KCS). Methods: In this ethics review board-approved retrospective study, six radiologists independently evaluated pancreatic CT-examinations of 30 patients randomly selected from a tertiary referral centre's multidisciplinary tumour board database. Based on well-defined criteria of tumour-vessel relationship, each patient was assigned to one of three NCCN and six KCS categories. We assessed the intraclass correlation coefficient (ICC) and compared the percentages of correct tumour classification of the six readers in both systems (Chi-square test; a P-value < 0.05 was considered significant). The standard of reference was a consensus evaluation of CT-examinations by three readers not involved in the image analysis. Results: The ICC for NCCN and KCS was 0.82 and 0.84, respectively (very strong agreement). The percentages of correct tumour classification at NCCN and KCS were 53-83% and 30-57%, respectively, with no statistically significant differences in the overall reader comparison per classification system. In pair-wise comparison between readers for NCCN/KCS, there were statistically significant differences between reader 5 vs. readers 4 (P = 0.012) and 3 (P = 0.045)/ reader 5 vs. reader 4 (P = 0.037). Conclusion: Interreader agreement in both PC classification systems is very strong. NCCN may be advantageous in terms of reader performance compared to KCS.
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| 40. |
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| 41. |
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| 42. |
- Macri, Erin M., et al.
(författare)
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Does patellar alignment or trochlear morphology predict worsening of patellofemoral disease within the first 5 years after anterior cruciate ligament reconstruction?
- 2019
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Ingår i: European Journal of Radiology. - : ELSEVIER IRELAND LTD. - 0720-048X .- 1872-7727. ; 113, s. 32-38
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: We described patellofemoral alignment and trochlear morphology at one and five years after anterior cruciate ligament reconstruction (ACLR), and evaluated the associations between alignment and trochlear morphology (at one year) and worsening patellofemoral osteoarthritis (OA) features by five years. We also evaluated the associations between alignment and morphology to self-reported pain and function (Knee injury and Osteoarthritis Outcome Score, KOOS) at five years. Materials and methods: In this longitudinal observational study, we followed 73 participants (mean age 29[9] years, 40% women) from one-to five-years after ACLR. Using MRI, we measured alignment and morphology, and scored cartilage and bone marrow lesions at both time points. We used mixed effects and linear regression models to achieve our stated aims. Results: Greater lateral patella displacement increased risk of cartilage worsening (Odds Ratio [95% CI]: 1.09 [1.01, 1.16]); while less lateral tilt (0.91 [0.83, 0.99]) and greater trochlear angle (0.88 [0.77, 1.00]) were protective. Greater medial trochlear inclination increased risk of bone marrow lesion worsening (1.12 [1.04, 1.19]); while greater trochlear angle was protective (0.80 [0.67, 0.96]). Greater lateral displacement was associated with worse self-reported KOOS sport and recreation scores (beta [95% CI]: -11.0 [-20.9, -1.2]) and quality of life scores (-10.5 [-20.4, -0.7]). Conclusions: Lateral displacement, lateral tilt, and morphology at 1 year post-ACLR altered the risk of worsening patellofemoral OA features four years later. Lateral displacement was the only measure associated with worse self-reported symptoms at five years. These findings may lead to novel treatment strategies for secondary prevention after ACLR.
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| 43. |
- Mantini, Cesare, et al.
(författare)
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Influence of image reconstruction parameters on cardiovascular risk reclassification by Computed Tomography Coronary Artery Calcium Score
- 2018
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Ingår i: European Journal of Radiology. - : Elsevier BV. - 0720-048X. ; 101, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To investigate the influence of different CT reconstruction parameters on coronary artery calcium scoring (CACS) values and reclassification of predicted cardiovascular (CV) risk. Methods: CACS was evaluated in 113 patients undergoing ECG-gated 64-slice CT. Reference CACS protocol included standard kernel filter (B35f) with slice thickness/increment of 3/1.5 mm, and field-of-view (FOV) of 150–180 mm. Influence of different image reconstruction algorithms (reconstructed slice thickness/increment 2.0/1.0–1.5/0.8–3.0/2.0–3.0/3.0 mm; slice kernel B30f-B45f; FOV 200–250 mm) on Agatston score was assessed by Bland-Altman plots and concordance correlation coefficient (CCC) analysis. Classification of CV risk was based on the Mayo Clinic classification. Results: Different CACS reconstruction parameters showed overall good accuracy and precision when compared with reference protocol. Protocols with larger FOV, thinner slices and sharper kernels were associated with significant CV risk reclassification. Use of kernel B45f showed a moderate positive correlation with reference CACS protocol (Agatston CCC = 0.67), and yielded significantly higher CACS values (p <.05). Reconstruction parameters using B30f or B45f kernels, 250 mm FOV, or slice thickness/increment of 2.0/1.0 mm or 1.5/0.8 mm, were associated with significant reclassification of CV risk (p <.05). Conclusions: Kernel, FOV, slice thickness and increment are major determinants of accuracy and precision of CACS measurement. Despite high agreement and overall good correlation of different reconstruction protocols, thinner slices thickness and increment, and sharper kernels were associated with significant upward reclassification of CV risk. Larger FOV determined both upward and downward reclassification of CV risk.
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| 44. |
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| 45. |
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| 46. |
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| 47. |
- Morcos, Sameh K., et al.
(författare)
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Reducing the risk of iodine-based and MRI contrast media administration : recommendation for a questionnaire at the time of booking
- 2008
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Ingår i: European Journal of Radiology. - : Elsevier BV. - 0720-048X .- 1872-7727. ; 66:2, s. 225-229
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a practical questionnaire to be used when a contrast medium examination is requested. The questionnaire is based on the guidelines from the European Society of Urogenital Radiology. Its aim is to identify patients at increased risk of clinically relevant renal and non-renal adverse reactions to iodine-based and MRI contrast agents. The questionnaire should be completed by the referring physician when the examination is requested.
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| 48. |
- Morgan, Alexandra R, et al.
(författare)
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Feasibility assessment of using oxygen-enhanced magnetic resonance imaging for evaluating the effect of pharmacological treatment in COPD.
- 2014
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Ingår i: European Journal of Radiology. - : Elsevier BV. - 1872-7727 .- 0720-048X. ; 83:11, s. 2093-2101
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Tidskriftsartikel (refereegranskat)abstract
- Oxygen-enhanced MRI (OE-MRI) biomarkers have potential value in assessment of COPD, but need further evaluation before treatment-induced changes can be interpreted. The objective was to evaluate how OE-MRI parameters of regional ventilation and oxygen uptake respond to standard pharmacological interventions in COPD, and how the response compares to that of gold standard pulmonary function tests.
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| 49. |
- Norén, Bengt, 1955-, et al.
(författare)
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Separation of advanced from mild fibrosis in diffuse liver disease using 31P magnetic resonance spectroscopy
- 2008
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Ingår i: European Journal of Radiology. - : Elsevier. - 0720-048X .- 1872-7727. ; 66:2, s. 313-320
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Tidskriftsartikel (refereegranskat)abstract
- 31P-MRS using DRESS was used to compare absolute liver metabolite concentrations (PME, Pi, PDE, γATP, αATP, βATP) in two distinct groups of patients with chronic diffuse liver disorders, one group with steatosis (NAFLD) and none to moderate inflammation (n = 13), and one group with severe fibrosis or cirrhosis (n = 16). All patients underwent liver biopsy and extensive biochemical evaluation. A control group (n = 13) was also included. Absolute concentrations and the anabolic charge, AC = {PME}/({PME} + {PDE}), were calculated.Comparing the control and cirrhosis groups, lower concentrations of PDE (p = 0.025) and a higher AC (p < 0.001) were found in the cirrhosis group. Also compared to the NAFLD group, the cirrhosis group had lower concentrations of PDE (p = 0.01) and a higher AC (p = 0.009). No significant differences were found between the control and NAFLD group. When the MRS findings were related to the fibrosis stage obtained at biopsy, there were significant differences in PDE between stage F0–1 and stage F4 and in AC between stage F0–1 and stage F2–3.Using a PDE concentration of 10.5 mM as a cut-off value to discriminate between mild, F0–2, and advanced, F3–4, fibrosis the sensitivity and specificity were 81% and 69%, respectively. An AC cut-off value of 0.27 showed a sensitivity of 93% and a specificity of 54%.In conclusion, the results suggest that PDE is a marker of liver fibrosis, and that AC is a potentially clinically useful parameter in discriminating mild fibrosis from advanced.
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| 50. |
- Persson, Anders, 1953-, et al.
(författare)
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Advances of dual source, dual-energy imaging in postmortem CT
- 2008
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Ingår i: European Journal of Radiology. - : Elsevier BV. - 0720-048X .- 1872-7727. ; 68:3, s. 446-455
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Tidskriftsartikel (refereegranskat)abstract
- This paper focuses on the use of multi-detector row dual-energy computed tomography (DECT) in the evaluation of postmortal examinations. The use of dual energy moves postmortem CT to an entirely new dimension of diagnostic sensitivity where contrast in the image is not merely limited to X-ray attenuation differences, but may include elements of functional and tissue characterization. This additional information may be used to improve the benefit postmortem imaging can provide to supplement and simplify the conventional autopsy. © 2008 Elsevier Ireland Ltd. All rights reserved.
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