| 1. |
- Alshamari, Muhammed, 1975-, et al.
(författare)
-
Impact of iterative reconstruction on image quality of low-dose CT of the lumbar spine
- 2017
-
Ingår i: Acta Radiologica. - London : Sage Publications. - 0284-1851 .- 1600-0455. ; 58:6, s. 702-709
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Iterative reconstruction (IR) is a recent reconstruction algorithm for computed tomography (CT) that can be used instead of the standard algorithm, filtered back projection (FBP), to reduce radiation dose and/or improve image quality.Purpose: To evaluate and compare the image quality of low-dose CT of the lumbar spine reconstructed with IR to conventional FBP, without further reduction of radiation dose.Material and Methods: Low-dose CT on 55 patients was performed on a Siemens scanner using 120 kV tube voltage, 30 reference mAs, and automatic dose modulation. From raw CT data, lumbar spine CT images were reconstructed with a medium filter (B41f) using FBP and four levels of IR (levels 2-5). Five reviewers scored all images on seven image quality criteria according to the European guidelines on quality criteria for CT, using a five-grade scale. A side-by-side comparison was also performed.Results: There was significant improvement in image quality for IR (levels 2-4) compared to FBP. According to visual grading regression, odds ratios of all criteria with 95% confidence intervals for IR2, IR3, IR4, and IR5 were: 1.59 (1.39-1.83), 1.74 (1.51-1.99), 1.68 (1.46-1.93), and 1.08 (0.94-1.23), respectively. In the side-by-side comparison of all reconstructions, images with IR (levels 2-4) received the highest scores. The mean overall CTDIvol was 1.70 mGy (SD 0.46; range, 1.01-3.83 mGy). Image noise decreased in a linear fashion with increased strength of IR.Conclusion: Iterative reconstruction at levels 2, 3, and 4 improves image quality of low-dose CT of the lumbar spine compared to FPB.
|
|
| 2. |
- Alshamari, Muhammed, 1975-, et al.
(författare)
-
Low dose CT of the lumbar spine compared with radiography : a study on image quality with implications for clinical practice
- 2016
-
Ingår i: Acta Radiologica. - London, United Kingdom : Sage Publications. - 0284-1851 .- 1600-0455. ; 57:5, s. 602-611
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Lumbar spine radiography is often performed instead of CT for radiation dose concerns.Purpose: To compare image quality and diagnostic information from low dose lumbar spine CT at an effective dose of about 1 mSv with lumbar spine radiography.Material and Methods: Fifty-one patients were examined by both methods. Five reviewers scored all examinations on eight image quality criteria using a five-graded scale and also assessed three common pathologic changes.Results: Low dose CT scored better than radiography on the following: sharp reproduction of disc profile and vertebral end-plates (odds ratio [OR], 1.8; 95% confidence interval [CI], 1.3-2.5), intervertebral foramina and pedicles (OR, 4.3; 95% CI, 3.1-5.9), intervertebral joints (OR, 139; 95% CI, 59-326), spinous and transverse processes (OR, 7.0; 95% CI, 4.3-11.2), sacro-iliac joints (OR, 4.2; 95% CI, 3.2-5.7), reproduction of the adjacent soft tissues (OR, 2.9; 95% CI, 2.1-4.0), and absence of any obscuring superimposed gastrointestinal gas and contents (OR, 188; 95% CI, 66-539). Radiography scored better on sharp reproduction of cortical and trabecular bone (OR, 0.3; 95% CI, 0.2-0.4). The reviewers visualized disk degeneration, spondylosis/diffuse idiopathic skeletal hyperostosis (DISH) and intervertebral joint osteoarthritis more clearly and were more certain with low dose CT. Mean time to review low dose CT was 204 s (95% CI, 194-214 s.), radiography 152 s (95% CI, 146-158 s.). The effective dose for low dose CT was 1.0-1.1 mSv, for radiography 0.7 mSv.Conclusion: Low dose lumbar spine CT at about 1 mSv has superior image quality to lumbar spine radiography with more anatomical and diagnostic information.
|
|
| 3. |
- Andersson, Karin M., 1989-, et al.
(författare)
-
Visual grading evaluation of commercially available metal artefact reduction techniques in hip prosthesis computed tomography
- 2016
-
Ingår i: British Journal of Radiology. - London, United Kingdom : British Institute of Radiology. - 0007-1285 .- 1748-880X. ; 89:1063
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives: To evaluate metal artefact reduction (MAR) techniques from four computed tomography (CT) vendors in hip prosthesis imaging.Methods: Bilateral hip prosthesis phantom images, obtained by using MAR algorithms for single energy CT data or dual energy CT (DECT) data and by monoenergetic reconstructions of DECT data, were visually graded by five radiologists using ten image quality criteria. Comparisons between the MAR images and a reference image were performed for each scanner separately. Ordinal probit regression analysis was used.Results: The MAR algorithms in general improved the image quality based on the majority of the criteria (up to between 8/10 and 10/10) with a statistically improvement in overall image quality (P<0.001). However, degradation of image quality, such as new artefacts, was seen in some cases. A few monoenergetic reconstruction series improved the image quality (P<0.004) for one of the DECT scanners, but it was only improved for some of the criteria (up to 5/10). Monoenergetic reconstructions resulted in worse image quality for the majority of the criteria (up to 7/10) for the other DECT scanner.Conclusions: The MAR algorithms improved the image quality of the hip prosthesis CT images. However, since additional artefacts and degradation of image quality were seen in some cases, all algorithms should be carefully evaluated for every clinical situation. Monoenergetic reconstructions were in general concluded to be insufficient for reducing metal artifacts. Advances in knowledge: Qualitative evaluation of the usefulness of several MAR techniques from different vendors in CT imaging of hip prosthesis.
|
|
| 4. |
- Alshamari, Muhammed, 1975-, et al.
(författare)
-
Diagnostic accuracy of low-dose CT compared with abdominal radiography in non-traumatic acute abdominal pain : prospective study and systematic review
- 2016
-
Ingår i: European Radiology. - New York : Springer. - 0938-7994 .- 1432-1084. ; 26:6, s. 1766-1774
-
Forskningsöversikt (refereegranskat)abstract
- Objectives: Abdominal radiography is frequently used in acute abdominal non-traumatic pain despite the availability of more advanced diagnostic modalities. This study evaluates the diagnostic accuracy of low-dose CT compared with abdominal radiography, at similar radiation dose levels.Methods: Fifty-eight patients were imaged with both methods and were reviewed independently by three radiologists. The reference standard was obtained from the diagnosis in medical records. Sensitivity and specificity were calculated. A systematic review was performed after a literature search, finding a total of six relevant studies including the present.Results: Overall sensitivity with 95 % CI for CT was 75 % (66-83 %) and 46 % (37-56 %) for radiography. Specificity was 87 % (77-94 %) for both methods. In the systematic review the overall sensitivity for CT varied between 75 and 96 % with specificity from 83 to 95 % while the overall sensitivity for abdominal radiography varied between 30 and 77 % with specificity 75 to 88 %.Conclusions: Based on the current study and available evidence, low-dose CT has higher diagnostic accuracy than abdominal radiography and it should, where logistically possible, replace abdominal radiography in the workup of adult patients with acute non-traumatic abdominal pain.Key points: • Low-dose CT has a higher diagnostic accuracy than radiography. • A systematic review shows that CT has better diagnostic accuracy than radiography. • Radiography has no place in the workup of acute non-traumatic abdominal pain.
|
|
| 5. |
- Geijer, Håkan, 1961-, et al.
(författare)
-
Added value of double reading in diagnostic radiology, a systematic review
- 2018
-
Ingår i: Insights into Imaging. - : Springer. - 1869-4101. ; 9:3, s. 287-301
-
Forskningsöversikt (refereegranskat)abstract
- OBJECTIVES: Double reading in diagnostic radiology can find discrepancies in the original report, but a systematic program of double reading is resource consuming. There are conflicting opinions on the value of double reading. The purpose of the current study was to perform a systematic review on the value of double reading.METHODS: A systematic review was performed to find studies calculating the rate of misses and overcalls with the aim of establishing the added value of double reading by human observers.RESULTS: The literature search resulted in 1610 hits. After abstract and full-text reading, 46 articles were selected for analysis. The rate of discrepancy varied from 0.4 to 22% depending on study setting. Double reading by a sub-specialist, in general, led to high rates of changed reports.CONCLUSIONS: The systematic review found rather low discrepancy rates. The benefit of double reading must be balanced by the considerable number of working hours a systematic double-reading scheme requires. A more profitable scheme might be to use systematic double reading for selected, high-risk examination types. A second conclusion is that there seems to be a value of sub-specialisation for increased report quality. A consequent implementation of this would have far-reaching organisational effects.KEY POINTS: • In double reading, two or more radiologists read the same images. • A systematic literature review was performed. • The discrepancy rates varied from 0.4 to 22% in various studies. • Double reading by sub-specialists found high discrepancy rates.
|
|
| 6. |
- Geijer, H, et al.
(författare)
-
Comparison of color LCD and medical-grade monochrome LCD displays in diagnostic radiology.
- 2007
-
Ingår i: Journal of Digital Imaging. - : Springer Science and Business Media LLC. - 0897-1889 .- 1618-727X. ; 20:2, s. 114-121
-
Tidskriftsartikel (refereegranskat)abstract
- Abstract In diagnostic radiology, medical-grade monochrome displays are usually recommended because of their higher luminance. Standard color displays can be used as a less expensive alternative, but have a lower luminance. The aim of the present study was to compare image quality for these two types of displays. Images of a CDRAD contrast-detail phantom were read by four radiologists using a 2-megapixel (MP) color display (143 cd/m2 maximum luminance) as well as 2-MP (295 cd/m2) and 3-MP monochrome displays. Thirty lumbar spine radiographs were also read by four radiologists using the color and the 2-MP monochrome display in a visual grading analysis (VGA). Very small differences were found between the displays when reading the CDRAD images. The VGA scores were −0.28 for the color and −0.25 for the monochrome display (p=0.24; NS). It thus seems possible to use color displays in diagnostic radiology provided that grayscale adjustment is used. Key words PACS - displays - digital imaging - luminance - image quality - monitor - medical imaging - liquid crystal display
|
|
| 7. |
|
|
| 8. |
- Geijer, Mats, 1957, et al.
(författare)
-
Health-related quality of life in early psoriatic arthritis compared with early rheumatoid arthritis and a general population
- 2021
-
Ingår i: Seminars in Arthritis and Rheumatism. - : Elsevier BV. - 0049-0172 .- 1532-866X. ; 51:1, s. 246-252
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: Both psoriatic arthritis (PsA) and rheumatoid arthritis (RA) have a significant impact on quality of life, but few reports have compared the two diseases. The current study assessed health-related quality of life (HRQoL) in PsA at diagnosis and after five years compared with early rheumatoid arthritis (RA) and a matched general population. Methods: Patients with early PsA and early RA included in two Swedish registries with HRQoL data measured by the Medical Outcomes Study Short Form 36 (SF-36) at baseline and at five years follow-up were included. Differences in SF-36 scores compared with the general population were calculated for each patient. Physical function, disease activity, the delay before diagnosis, pain, and general wellbeing were used as explanatory variables. Statistical tests included t-tests and univariate and multivariate linear regression. Results: PsA (n = 166) and RA (n = 133) patients of both sexes had significantly reduced HRQoL at disease onset. After five years, PsA patients still had impairments in several domains of SF-36, whereas RA patients had an almost normalized HRQoL. The time from symptom onset to diagnosis, disease activity, and disability independently contributed to the reduced improvement in PsA. Conclusion: Both early PsA and RA are characterized by severely reduced HRQoL. Despite more severe disease at inclusion, normalization of HRQoL is seen in patients with RA but not PsA. This may be due to delay in the diagnosis of PsA or more powerful interventions in RA. Earlier detection, lifestyle intervention, and more aggressive management strategies may be needed for PsA. (C) 2020 Elsevier Inc. All rights reserved.
|
|
| 9. |
- Geijer, Mats, 1957-, et al.
(författare)
-
Tomosynthesis of the thoracic spine : added value in diagnosing vertebral fractures in the elderly
- 2017
-
Ingår i: European Radiology. - New York : Springer. - 0938-7994 .- 1432-1084. ; 27:2, s. 491-497
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives: Thoracic spine radiography becomes more difficult with age. Tomosynthesis is a low-dose tomographic extension of radiography which may facilitate thoracic spine evaluation. This study assessed the added value of tomosynthesis in imaging of the thoracic spine in the elderly.Methods: Four observers compared the image quality of 50 consecutive thoracic spine radiography and tomosynthesis data sets from 48 patients (median age 67 years, range 55-92 years) on a number of image quality criteria. Observer variation was determined by free-marginal multirater kappa. The conversion factor and effective dose were determined from the dose-area product values.Results: For all observers significantly more vertebrae were seen with tomosynthesis than with radiography (mean 12.4/9.3, P < 0.001) as well as significantly more fractures (mean 0.9/0.7, P = 0.017). The image quality score for tomosynthesis was significantly higher than for radiography, for all evaluated structures. Tomosynthesis took longer to evaluate than radiography. Despite this, all observers scored a clear preference for tomosynthesis. Observer agreement was substantial (mean κ = 0.73, range 0.51-0.94). The calibration or conversion factor was 0.11 mSv/(Gy cm(2)) for the combined examination. The resulting effective dose was 0.87 mSv.Conclusion: Tomosynthesis can increase the detection rate of thoracic vertebral fractures in the elderly, at low added radiation dose.KEY POINTS:• Tomosynthesis helps evaluate the thoracic spine in the elderly. • Observer agreement for thoracic spine tomosynthesis was substantial (mean κ = 0.73). • Significantly more vertebrae and significantly more fractures were seen with tomosynthesis. • Tomosynthesis took longer to evaluate than radiography. • There was a clear preference among all observers for tomosynthesis over radiography.
|
|
| 10. |
- Abramo, Antonio, et al.
(författare)
-
Osteotomy of distal radius fracture malunion using a fast remodeling bone substitute consisting of calcium sulphate and calcium phosphate.
- 2010
-
Ingår i: Journal of biomedical materials research. Part B, Applied biomaterials. - : Wiley. - 1552-4981 .- 1552-4973. ; 92:1, s. 281-6
-
Tidskriftsartikel (refereegranskat)abstract
- Malunion after a distal radius fracture can be treated with an osteotomy of the distal radius. Autologous iliac crest bone graft is often used to fill the gap, but the procedure is associated with donor site morbidity. In this study a novel fast resorbing biphasic bone substitute consisting of a mixture of calcium sulphate and calcium phosphate is used (Cerament BoneSupport AB, Sweden). Fifteen consecutive patients, with a mean age of 52 (27-71) years were included. All had a malunion after a distal radius fracture and underwent an osteotomy. A fragment specific fixation system, TriMed (TriMed, Valencia, CA), consisting of a Buttress Pin and a Radial Pin Plate were used for fixation and a calcium sulphate and calcium phosphate mixture as bone substitute. The patients were followed for 1 year. Grip strength increased from 61 (28-93)% of the contralateral hand to 85 (58-109)%, p < 0.001. DASH scores decreased from 37 (22-61) to 24 (2-49) p = 0.003. Radiographically all osteotomies healed. An increase of ulnar variance was noted during healing from 1.8 mm immediately postoperatively to 2.6 mm at final follow up. Osteotomy can increase grip strength and decease disability after a malunited fracture. In the present series the bone substitute was replaced by bone, but a minor loss of the achieved radiographic correction was noted in some patients during osteotomy healing. A more rigid fixation may improve the radiographic outcome with this kind of bone substitute.
|
|
