| 1. |
- Alshamari, Muhammed, 1975-, et al.
(författare)
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Diagnostic accuracy of low-dose CT compared with abdominal radiography in non-traumatic acute abdominal pain : prospective study and systematic review
- 2016
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Ingår i: European Radiology. - New York : Springer. - 0938-7994 .- 1432-1084. ; 26:6, s. 1766-1774
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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.
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| 2. |
- Alshamari, Muhammed, 1975-, et al.
(författare)
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Impact of iterative reconstruction on image quality of low-dose CT of the lumbar spine
- 2017
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Ingår i: Acta Radiologica. - London : Sage Publications. - 0284-1851 .- 1600-0455. ; 58:6, s. 702-709
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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.
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| 3. |
- Alshamari, Muhammed, 1975-, et al.
(författare)
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Low dose CT of the lumbar spine compared with radiography : a study on image quality with implications for clinical practice
- 2016
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Ingår i: Acta Radiologica. - London, United Kingdom : Sage Publications. - 0284-1851 .- 1600-0455. ; 57:5, s. 602-611
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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.
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| 4. |
- Andersson, Karin M., 1989-, et al.
(författare)
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Visual grading evaluation of commercially available metal artefact reduction techniques in hip prosthesis computed tomography
- 2016
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Ingår i: British Journal of Radiology. - London, United Kingdom : British Institute of Radiology. - 0007-1285 .- 1748-880X. ; 89:1063
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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.
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| 5. |
- Geijer, Håkan, 1961-, et al.
(författare)
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Added value of double reading in diagnostic radiology, a systematic review
- 2018
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Ingår i: Insights into Imaging. - : Springer. - 1869-4101. ; 9:3, s. 287-301
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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.
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| 6. |
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| 7. |
- Geijer, Mats, 1957-, et al.
(författare)
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Tomosynthesis of the thoracic spine : added value in diagnosing vertebral fractures in the elderly
- 2017
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Ingår i: European Radiology. - New York : Springer. - 0938-7994 .- 1432-1084. ; 27:2, s. 491-497
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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.
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| 8. |
- Ah, Rebecka, et al.
(författare)
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Prognostic Value of P-POSSUM and Osteopenia for Predicting Mortality After Emergency Laparotomy in Geriatric Patients
- 2019
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Ingår i: Bulletin of emergency and trauma. - : Shiraz University of Medical Sciences. - 2322-2522 .- 2322-3960. ; 7:3, s. 223-231
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To evaluate the Portsmouth-Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (P-POSSUM) in comparison with other risk factors for mortality including osteopenia as an indicator for frailty in geriatric patients subjected to emergency laparotomy.Methods: All geriatric patients (≥65 years) undergoing emergency laparotomy at a single university hospital between 1/2015 and 12/2016 were included in this cohort study. Demographics and outcomes were retrospectively collected from medical records. Association between prognostic markers and 30-day mortality was assessed using Poisson and backward stepwise regression models. Prognostic value was assessed using receiver operating characteristic (ROC) curves.Results: =0.004) while osteopenia was not. P-POSSUM had poor prognostic value for 30-day mortality with an area under the ROC curve (AUC) of 0.59. The prognostic value of P-POSSUM improved significantly when adjusting for patient covariates (AUC=0.83).Conclusion: P-POSSUM and osteopenia alone hardly predict 30-day mortality in geriatric patients following emergency laparotomy. P-POSSUM adjusted for other patient covariates improves the prediction.
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| 9. |
- Alshamari, Muhammed, 1975-
(författare)
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Low-dose computed tomography of the abdomen and lumbar spine
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Radiography is a common radiologic investigation despite abundant evidence of its limited diagnostic value. On the other hand, computed tomography (CT) has a high diagnostic value and is widely considered to be among the most important advances in medicine. However, CT exposes patients to a higher radiation dose and it might therefore not be acceptable simply to replace radiography with CT, despite the powerful diagnostic value of this technique. At the expense of reduced CT image quality, which could be adjusted to the diagnostic needs, low-dose CT of abdomen and lumbar spine can be performed at similar dose to radiography. The aim of the current thesis project was to evaluate low-dose CT of the abdomen and lumbar spine and to compare it with radiography. The hypothesis was that CT would give better image quality and diagnostic information compared to radiography at similar dose levels. Firstly, the diagnostic accuracy of low-dose CT of the abdomen was evaluated. Results showed that low-dose CT of abdomen has a high sensitivity and specificity compared to radiography, i.e., it has higher diagnostic accuracy. Similar results were obtained from our systematic review. Secondly, in a phantom study, an ovine phantom was scanned at various CT settings. The image quality was evaluated to obtain a protocol for the optimal settings for low-dose CT of lumbar spine at 1 mSv. This new protocol was then used in a clinical study to assess the image quality of low-dose CT of the lumbar spine and compare it to radiography. Results showed that low-dose CT has significantly better image quality than radiography. Finally, the impact of Iterative reconstruction (IR) on image quality of lumbar spine CT was tested. Iterative reconstruction is a recent CT technique aimed to reduce radiation dose and/or improve image quality. The results showed that the use of medium strength IR levels in the reconstruction of CT image improves image quality compared to filtered back projection. In conclusion, low-dose CT of the abdomen and lumbar spine, at about 1 mSv, has better image quality and gives diagnostic information compared to radiography at similar dose levels and it could therefore replace radiography.
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| 10. |
- Bäck, Anna, 1976-, et al.
(författare)
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Diuretic decision seven minutes post Tc-99m-MAG3 administration in a renography
- 2018
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Ingår i: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer. - 1619-7070 .- 1619-7089. ; 45:Suppl. 1, s. S765-S765
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Aim: The F+10 method in supine position, which has been implemented at our Nuclear Medicine department since 2015, involves a 30- minute long dynamic acquisition. The diuretic is only administered when necessary and decision is taken by the radiographers in a semi-automated fashion without consulting a physician, by calculating the remaining activity in the kidneys seven minutes post 99mTc-MAG3 injection and comparing the value with an arbitrary threshold of 75 %. If needed, the diuretic is injected three minutes later. The aim of this study was to correlate our method with the established previously used F+20 protocol in adults. Is the currently used threshold of 75% of activity left in any kidney at seven minutes the optimal cut-off value for diuretic administration?Material and Methods: This is an ongoing retrospective study which include 320 F+20 examinations of adult patients performed during 2013-2015. They were all re-evaluated according to the currently used F+10 method, categorized as requiring diuretic or not and correlated to the original F+20 examination. A ROC-curve was drawn to delineate the best cut-off value for remaining renal activity. Sensitivity, specificity and accuracy were calculated.Results: Preliminary results indicate that the F+10 re-evaluations with the currently used cut-off value of 75% did not correlate with the original F+20 examinations. In 80% (255 examinations) of the F+10 re-evaluations diuretic would have been considered necessary while only 52% (167 examinations) received diuretics in the original F+20 renographies (sensitivity 1.0, specificity 0.42). However, all the patients who required furosemide in the original F+20 renographies would have received diuretic if they had been imaged with the F+10 protocol. Furthermore, examination time is considerably reduced. After an evaluation of the ROC-curve the optimal cut-off value was 94% (sensitivity 0.92, specificity 0.84, accuracy 0.88). However, by implementing this value, 13 patients (4%) would have been falsely categorized as not requiring diuretic.Conclusions: The 99mTc-MAG3 renography with the F+10 protocol in supine position is a feasible and acceptable method in clinical practice.
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| 11. |
- Ferrari, Gabriele, 1984-, et al.
(författare)
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PCI in saphenous vein graft after CABG : a review of the international literature
- 2019
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Ingår i: Book of abstracts. - : School of Health Sciences and School of Medical Sciences, Örebro University. - 9789187789304
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Konferensbidrag (refereegranskat)abstract
- Background/objectives: To review the international literature about the use of Percutaneous Coronary Intervention (PCI) in vena saphena magna graft after a Coronary Artery Bypass Grafting (CABG).Methods: We reviewed, from three different databases, the recent international literature (published between January 1, 2000 and December 31, 2018) regarding the use of PCI invenous grafts. Two independent researchers performed the literature search, designed after a PICO model. Forty articles were selected and a quality assessment was performed.Results: We noticed a high percentage of short and long-term cardiac events. The peri-procedural failure rate, due to residual stenos, had a mean value around 10%. The 30-days MACE (major adverse cardiac event) had a mean value of 6-7%, with the lower rates associated with the use of embolic protection devices. The MACE rates at 1 year reported were above 10% for most reports (up to over 30%; mean 16%), with better results after the use of a drug-eluting stent (DES) instead of a bare-metal stent. The long-term MACE (2-5 years) reported was high in all studies, with values ranging between 18% and 58%, with target vessel revascularization rates between 9% and 44%. The benefits of DES no longer remain in the long term.Conclusions: The percutaneous intervention of an occluded or stenosed saphenous vein graftis a challenge for the angiographer and is still associated with high rates of failure, MACE and restenosis. The key of the success of the procedure seems to be to optimize the quality of the venous graft itself.
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| 12. |
- Geijer, Håkan, 1961-, et al.
(författare)
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Temperature measurements with a temporal scanner : systematic review and meta-analysis
- 2016
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Ingår i: BMJ Open. - London, United Kingdom : BMJ Group. - 2044-6055. ; 6:3
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Forskningsöversikt (refereegranskat)abstract
- Objectives: Systematic review and meta-analysis on the diagnostic accuracy of temporal artery thermometers (TAT).Design: Systematic review and meta-analysis. The index test consisted of temperature measurement with TAT. The reference test consisted of an estimation of core temperature.Participants: Clinical patients as well as healthy participants, with or without fever.Interventions: Literature search in PubMed, Embase, Cinahl and Web of Science. Three reviewers selected articles for full-text reading after which a further selection was made. Risk of bias was assessed with QUADAS-2. Pooled difference and limits of agreement (LoA) were estimated with an inverse variance weighted approach. Subgroup and sensitivity analyses were performed. Sensitivity and specificity were estimated using hierarchical models. Quality of evidence was assessed according to the GRADE system.Primary and secondary outcome measures: The primary outcome was measurement accuracy expressed as mean difference ±95% LoA. A secondary outcome was sensitivity and specificity to detect fever. If tympanic thermometers were assessed in the same population as TAT, these results were recorded as well.Results: 37 articles comprising 5026 participants were selected. Pooled difference was -0.19°C (95% LoA -1.16 to 0.77°C), with moderate quality of evidence. Pooled sensitivity was 0.72 (95% CI 0.61 to 0.81) with a specificity of 0.94 (95% CI 0.87 to 0.97). The subgroup analysis revealed a trend towards underestimation of the temperature for febrile patients. There was a large heterogeneity among included studies with wide LoA which reduced the quality of evidence.Conclusions: TAT is not sufficiently accurate to replace one of the reference methods such as rectal, bladder or more invasive temperature measurement methods. The results are, however, similar to those with tympanic thermometers, both in our meta-analysis and when compared with others. Thus, it seems that TAT could replace tympanic thermometers with the caveat that both methods are inaccurate.Trial registration number: CRD42014008832.
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| 13. |
- Gustafsson, Agneta, et al.
(författare)
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A visual grading study for different administered activity levels in bone scintigraphy
- 2015
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Ingår i: Clinical Physiology and Functional Imaging. - : Wiley-Blackwell. - 1475-0961 .- 1475-097X. ; 35:3, s. 231-236
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: The aim of the study is to assess the administered activity levels versus visual-based image quality using visual grading regression (VGR) including an assessment of the newly stated image criteria for whole-body bone scintigraphy.Materials and methods: A total of 90 patients was included and grouped in three levels of administered activity: 400, 500 and 600 MBq. Six clinical image criteria regarding image quality was formulated by experienced nuclear medicine physicians. Visual grading was performed in all images, where three physicians rated the fulfilment of the image criteria on a four-step ordinal scale. The results were analysed using VGR. A count analysis was also made where the total number of counts in both views was registered.Results: The administered activity of 600 MBq gives significantly better image quality than 400 MBq in five of six criteria (P<005). Comparing the administered activity of 600 MBq to 500 MBq, four criteria of six show significantly better image quality (P<005). The administered activity of 500 MBq gives no significantly better image quality than 400 Mbq (P<005). The count analysis shows that none of the three levels of administrated activity fulfil the recommendations by the EANM.Conclusion: There was a significant improvement in perceived image quality using an activity level of 600 MBq compared to lower activity levels in whole-body bone scintigraphy for the gamma camera equipment end set-up used in this study. This type of visual-based grading study seems to be a valuable tool and easy to implement in the clinical environment.
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| 14. |
- Jendeberg, Johan, 1972-, et al.
(författare)
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Prediction of spontaneous ureteral stone passage : Automated 3D-measurements perform equal to radiologists, and linear measurements equal to volumetric
- 2018
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Ingår i: European Radiology. - : Springer. - 0938-7994 .- 1432-1084. ; 28:6, s. 2474-2483
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To compare the ability of different size estimates to predict spontaneous passage of ureteral stones using a 3D-segmentation and to investigate the impact of manual measurement variability on the prediction of stone passage.METHODS: We retrospectively included 391 consecutive patients with ureteral stones on non-contrast-enhanced CT (NECT). Three-dimensional segmentation size estimates were compared to the mean of three radiologists' measurements. Receiver-operating characteristic (ROC) analysis was performed for the prediction of spontaneous passage for each estimate. The difference in predicted passage probability between the manual estimates in upper and lower stones was compared.RESULTS: The area under the ROC curve (AUC) for the measurements ranged from 0.88 to 0.90. Between the automated 3D algorithm and the manual measurements the 95% limits of agreement were 0.2 ± 1.4 mm for the width. The manual bone window measurements resulted in a > 20 percentage point (ppt) difference between the readers in the predicted passage probability in 44% of the upper and 6% of the lower ureteral stones.CONCLUSIONS: All automated 3D algorithm size estimates independently predicted the spontaneous stone passage with similar high accuracy as the mean of three readers' manual linear measurements. Manual size estimation of upper stones showed large inter-reader variations for spontaneous passage prediction.KEY POINTS:• An automated 3D technique predicts spontaneous stone passage with high accuracy.• Linear, areal and volumetric measurements performed similarly in predicting stone passage.• Reader variability has a large impact on the predicted prognosis for stone passage.
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| 15. |
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| 16. |
- Jendeberg, Johan, 1972-, et al.
(författare)
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Size matters : The width and location of a ureteral stone accurately predict the chance of spontaneous passage
- 2017
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Ingår i: European Radiology. - : Springer. - 0938-7994 .- 1432-1084. ; 27:11, s. 4775-4785
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To determine how to most accurately predict the chance of spontaneous passage of a ureteral stone using information in the diagnostic non-enhanced computed tomography (NECT) and to create predictive models with smaller stone size intervals than previously possible.METHODS: Retrospectively 392 consecutive patients with ureteric stone on NECT were included. Three radiologists independently measured the stone size. Stone location, side, hydronephrosis, CRP, medical expulsion therapy (MET) and all follow-up radiology until stone expulsion or 26 weeks were recorded. Logistic regressions were performed with spontaneous stone passage in 4 weeks and 20 weeks as the dependent variable.RESULTS: The spontaneous passage rate in 20 weeks was 312 out of 392 stones, 98% in 0-2 mm, 98% in 3 mm, 81% in 4 mm, 65% in 5 mm, 33% in 6 mm and 9% in ≥6.5 mm wide stones. The stone size and location predicted spontaneous ureteric stone passage. The side and the grade of hydronephrosis only predicted stone passage in specific subgroups.CONCLUSION: Spontaneous passage of a ureteral stone can be predicted with high accuracy with the information available in the NECT. We present a prediction method based on stone size and location.KEY POINTS: • Non-enhanced computed tomography can predict the outcome of ureteral stones. • Stone size and location are the most important predictors of spontaneous passage. • Prediction models based on stone width or length and stone location are introduced. • The observed passage rates for stone size in mm-intervals are reported. • Clinicians can make better decisions about treatment.
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| 17. |
- Kataria, Bharti, 1955-
(författare)
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Visual grading evaluation of reconstruction methods and dose optimisation in abdominal Computed Tomography
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Since its introduction in the 1970’s CT has emerged as a modality of choice because of its high sensitivity in producing accurate diagnostic images. A third of all Computed Tomography (CT) examinations are abdominal CTs which deliver one of the highest doses among common examinations. An increase in the number of CT examinations has raised concerns about the negative effects of ionising radiation as the dose is cumulative over the life span of the individual. Image quality in CT is closely related to the radiation dose, so that a certain dose with an associated small, but not negligible, risk is a prerequisite for high image quality. Typically, dose reduction in CT results in higher noise and a decrease in low contrast resolution which can be detrimental to the image quality produced. New technology presents a wide range of dose reduction strategies, the latest being iterative reconstruction (IR).The aim of this thesis was to evaluate two different classes of iterative reconstruction algorithms: statistical (SAFIRE) and model-based (ADMIRE) as well as to explore the diagnostic value of a low-dose abdominal CT for optimisation purposes.This thesis included a total of 140 human subjects in four image quality evaluation studies, three of which were prospective studies (Papers I, II and IV) and one retrospective study (Paper III). Visual grading experiments to determine the potential dose reductions, were performed with pairwise comparison of image quality in the same patient at different tube loads (dose) and reconstructed with Filtered back projection (FBP) and SAFIRE strength 1 in a low-dose abdominal CT (Paper I) and FBP and ADMIRE strengths 3 and 5 in a standard dose abdominal CT (Paper II). Paper IV evaluated the impact of slice thicknesses in CT images reconstructed with ADMIRE strengths 3 and 5 when comparing multiplanar reconstruction (MPR) formatted images in a standard dose abdominal CT. Paper III, on the other hand, was an absolute assessment of image quality and pathology between the three phases of a CT Urography (CTU) protocol to explore the diagnostic value of low-dose abdominal CT. The anonymised images were displayed in random order and image quality was assessed by a group of radiologists using image quality criteria from the “European guidelines of quality criteria for CT”. The responses from the reviewer assessment were analysed statistically with ordinal logistic regression i.e. Visual Grading Regression (VGR).Results in Paper I show that a small dose reduction (5-9 %) was possible using SAFIRE strength 1and indicated the need for further research to evaluate the dose reduction potential of higher strengths of the algorithm. In Paper II a 30% dose reduction was possible without change in ADMIRE algorithm strength as no improvement in image quality was observed between tube loads 98- and 140 mAs. When comparing tube loads 42 and 98 mAs, further dose reduction was possible with ADMIRE strength 3 (22-47%). However, for images reconstructed with ADMIRE strength 5, a dose reduction of 34-74% was possible for some, but not all image criteria. Image quality in low-contrast objects such as the liver parenchyma, was affected and a decline in diagnostic confidence was observed. Paper IV showed potential dose reductions are possible with increasing slice thickness from 1 mm to 2 mm (24-35%) and 1 mm to 3mm (25-41%). ADMIRE strength 3 continued to provide diagnostically acceptable images with possible dose reductions for all image criteria assessed. Despite objective evaluations showing a decrease in noise and an increase in contrast to noise ratio, ADMIRE strength 5 had diverse effects on the five image criteria, depending on slice thickness and further dose reductions were limited to certain image criteria. The findings do not support a general recommendation to replace ADMIRE3 with ADMIRE5 in clinical abdominal CT protocols.Paper III studied another aspect of optimisation and results show that visualisation of renal anatomy was as expected in favour of the post-contrast phases when compared to the native phase. Assessment of pathology showed no significant differences between the three phases. Significantly higher diagnostic certainty for renal anatomy was observed for the post-contrast phases when compared to the native phase. Significantly high certainty scores were also seen for the nephrographic phase for incidental findings. The conclusion is that a low-dose series seems to be sufficient as a first-line modality in certain patient groups.This thesis clinically evaluated the effect of IR in abdominal CT imaging and estimated potential dose reductions. The important conclusion from papers I, II and IV is that IR improves image quality in abdominal CT allowing for some dose reductions. However, the clinical utility of the highest strength of the algorithm is limited to certain criteria. The results can be used to optimise the clinical abdominal CT protocol. The conclusion from paper III may increase clinical awareness of the value of the low-dose abdominal protocol when choosing an imaging method for certain patient groups who are more sensitive to radiation.
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| 18. |
- Lidén, Mats, 1976-, et al.
(författare)
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Two- and three-dimensional CT measurements of urinary calculi length and width : a comparative study
- 2015
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Ingår i: Acta Radiologica. - : Sage Publications. - 0284-1851 .- 1600-0455. ; 56:4, s. 487-492
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Tidskriftsartikel (refereegranskat)abstract
- Background: The standard imaging procedure for a patient presenting with renal colic is unenhanced computed tomography (CT). The CT measured size has a close correlation to the estimated prognosis for spontaneous passage of a ureteral calculus. Size estimations of urinary calculi in CT images are still based on two-dimensional (2D) reformats.Purpose: To develop and validate a calculus oriented three-dimensional (3D) method for measuring the length and width of urinary calculi and to compare the calculus oriented measurements of the length and width with corresponding 2D measurements obtained in axial and coronal reformats.Material and Methods: Fifty unenhanced CT examinations demonstrating urinary calculi were included. A 3D symmetric segmentation algorithm was validated against reader size estimations. The calculus oriented size from the segmentation was then compared to the estimated size in axial and coronal 2D reformats.Results: The validation showed 0.1 +/- 0.7mm agreement against reference measure. There was a 0.4mm median bias for 3D estimated calculus length compared to 2D (P < 0.001), but no significant bias for 3D width compared to 2D.Conclusion: The length of a calculus in axial and coronal reformats becomes underestimated compared to 3D if its orientation is not aligned to the image planes. Future studies aiming to correlate calculus size with patient outcome should use a calculus oriented size estimation.
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| 19. |
- Piippo-Huotari, Oili, 1959-, et al.
(författare)
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New patient-controlled abdominal compression method in radiography : radiation dose and image quality
- 2018
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Ingår i: Acta Radiologica Open. - : Sage Publications. - 2058-4601. ; 7:5, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- Background: The radiation dose for patients can be reduced with many methods and one way is to use abdominal compression. In this study, the radiation dose and image quality for a new patient-controlled compression device were compared with conventional compression and compression in the prone position.Purpose: To compare radiation dose and image quality of patient-controlled compression compared with conventional and prone compression in general radiography.Material and Methods: An experimental design with quantitative approach. After obtaining the approval of the ethics committee, a consecutive sample of 48 patients was examined with the standard clinical urography protocol. The radiation doses were measured as dose-area product and analyzed with a paired t-test. The image quality was evaluated by visual grading analysis. Four radiologists evaluated each image individually by scoring nine criteria modified from the European quality criteria for diagnostic radiographic images.Results: There was no significant difference in radiation dose or image quality between conventional and patient-controlled compression. Prone position resulted in both higher dose and inferior image quality.Conclusion: Patient-controlled compression gave similar dose levels as conventional compression and lower than prone compression. Image quality was similar with both patient-controlled and conventional compression and was judged to be better than in the prone position.
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| 20. |
- Samano, Ninos, 1972-, et al.
(författare)
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Graft patency is associated with higher health-related quality of life after coronary artery bypass surgery
- 2016
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Ingår i: Interactive Cardiovascular and Thoracic Surgery. - Oxford, USA : Oxford University Press. - 1569-9293 .- 1569-9285. ; 24:3, s. 388-394
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The objective of this study was to investigate whether graft patency was associated with higher health-related quality of life in coronary artery bypass grafting patients and to compare this study with the general Swedish population.Methods: Patients were included from 3 randomized trials and 1 prospective cohort trial. The generic health-related quality of life instrument, EQ-5D (VAS and index) was used. Graft patency was assessed with computed tomography angiography. Patients were divided into 2 groups according to the number of occluded distal anastomosis: Group I with no to 1 occlusion (n = 209) and Group II with 2 to 4 occlusions (n = 24).Results: Two hundred and thirty-three patients underwent computed tomography angiography at a mean of 7.5 (1-18) years post-operatively. The mean difference in EQ-VAS and EQ-5D index between Groups II and I after model adjustment was -19.8 (95% CI -25.3 to -14.3; P < 0.001) and -0.13 (95% CI -0.19 to -0.08; P < 0.001), respectively. The EQ-5D index for the study population was similar compared with the Swedish population, 0.851 and 0.832, respectively, with an effect-size of 0.112 (trivial). The EQ-5D index of the study population was higher compared with the ischemic heart disease group in the Swedish population, 0.851 vs 0.60, with an effect-size of 0.999 (large).Conclusion: Graft patency was associated with higher health-related quality of life in coronary artery bypass patients. This patient group reported similar function and wellbeing compared to the general Swedish population and better health status than those in the same disease group in the general population.Clinical registration number: Clinicaltrials.gov: NCT02547194 and the Research and Development registry in Sweden: 167861.
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| 21. |
- Samano, Ninos, 1972-
(författare)
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No-Touch Saphenous Veins in Coronary Artery Bypass Grafting : Long-term Angiographic, Surgical, and Clinical Aspects
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Ischemic heart disease is currently the leading cause of death globally. Coronary artery bypass grafting (CABG) is considered the best treatment for many patients and its success depends on the long-term patency of the conduits. Greater use of arterial grafts has been advocated because of their higher long-term patency compared to saphenous vein grafts (SVGs). Despite this, SVGs account for up to 80% of all grafts used in CABG. Consequently, the long-term patency of the saphenous vein (SV) is one of the most crucial challenges in cardiovascular surgery. The no-touch (NT) SV in CABG has shown a superior patency rate, slower progression of atherosclerosis, and better clinical outcome compared to conventional veins up to 8.5 years postoperatively. The aim of this thesis was to study the long-term angiographic, echocardiographic, and clinical aspects of CABG patients receiving either NT or conventional vein grafts and to investigate the health-related quality of life (HRQoL) in this patient group. Studies I-II report a randomized trial between NT and conventional veins where 74 patients were followed-up at a mean of 16 years postoperatively. Study III is a prospective cohort trial in which 97 patients with NT vein grafts anastomosed to the left anterior descending artery (LAD) were included and followed-up at a mean of 6 years postoperatively. Study IV included 257 patients in whom HRQoL and graft patency were studied during the same follow-up visit. Overall, NT vein grafts showed a higher patency compared to conventional veins at a mean of 16 years, 83% vs. 64% (p=0.03), which was similar to the patency of the left internal thoracic artery, 88%. The NT group had a better left ventricular ejection fraction compared to the conventional group, 57.9% vs. 49.4% (p=0.011). After a mean of 6 years, the patency rate of NT SVs to the LAD was 95.6% and to non-LAD targets, 93.9%. Graft patency was an independent predictor of HRQoL in CABG patients. These patients reported a function and wellbeing similar to that of the Swedish population and clearly higher health status than those in the same disease group in the general population.
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| 22. |
- Samano, Ninos, 1972-, et al.
(författare)
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The no-touch saphenous vein for coronary artery bypass grafting maintains a patency, after 16 years, comparable to the left internal thoracic artery : a randomized trial
- 2015
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Ingår i: Journal of Thoracic and Cardiovascular Surgery. - : Mosby-Elsevier. - 0022-5223 .- 1097-685X. ; 150:4, s. 880-888
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: This study investigates whether the no-touch (NT) vein graft, at a mean time of 16 years, maintains a significantly higher patency rate than conventional (C) vein grafts and still has patency comparable to that of the left internal thoracic artery (LITA).Methods: A total of 156 patients accepted for coronary artery bypass grafting were randomly allocated to 1 of 3 groups. In the C group, the saphenous vein (SV) was stripped and distended. In the intermediate group, the SV was stripped but not distended. In the NT group, the SV was neither stripped nor distended, but rather harvested with a fat pedicle. This study is an angiographic follow-up of the C and NT groups, at a mean time of 16 years postoperatively.Results: Fifty-four patients were included (C group = 27; NT group = 27). In all, 72 and 75 vein grafts were completed in groups C and NT, respectively. Crude SV graft patency was 64% in the C group versus 83% in the NT group (P = .03), which was similar to the patency of the LITA (88%). The harvesting technique had a major impact on the patency with a hazard ratio for occlusion of 1.83 for the C group (P = .04).Conclusions: Harvesting the SV with the NT technique conferred, at a mean time of 16 years, a significantly higher patency than the conventional technique that was still comparable to that of the LITA.
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| 23. |
- Samano, Ninos, 1972-, et al.
(författare)
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The no-touch saphenous vein graft in elderly coronary bypass patients with multiple comorbidities is a promising conduit to substitute the left internal thoracic artery
- 2017
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Ingår i: Journal of Thoracic and Cardiovascular Surgery. - : Mosby Inc.. - 0022-5223 .- 1097-685X. ; 154:2, s. 457-466.e3
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: We investigated the patency rates of no-touch saphenous vein grafts anastomosed to the left anterior descending artery compared with the left internal thoracic artery. Further, we compared the patency of no-touch vein grafts to the left anterior descending artery with the patency of no-touch vein grafts to other coronary arteries.METHODS: Of 2635 consecutive patients undergoing coronary artery bypass grafting between 2003 and 2008, 168 (6.3%) were given at least a saphenous vein graft to the left anterior descending artery to avoid harvesting complications in high-risk patients or in response to a left internal thoracic artery injury. A total of 97 patients were consecutively included after informed consent. A clinical examination and computed tomography angiography were performed on 91 patients at a mean of 6 (4-9) years.RESULTS: The mean age of patients was 75.6 ± 8.5 years. Postoperatively, 88.7% of patients (86/97) were free of angina. The 91 examined patients had 163 grafts with 286 distal anastomoses. Crude patency, according to distal anastomoses, was 94.4% (270/286). The patency of single versus sequential no-touch vein grafts to the left anterior descending artery was 98% (50/51) versus 92.5% (37/40). The total patency rate was 95.6% (87/91), similar to the reported patency rate for the left internal thoracic artery. The no-touch grafts to the left anterior descending artery versus other coronaries had a patency of 95.6% (87/91) versus 93.8% (183/195), a high similarity confirmed by an equivalence analysis.CONCLUSIONS: In elderly coronary bypass patients with multiple comorbidities, a no-touch saphenous vein graft is a promising substitute for the left internal thoracic artery.
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| 24. |
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| 25. |
- Savvopoulos, Christos, et al.
(författare)
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99mTc-MIBI Embolus in the Late Phase of a Parathyroid Scan
- 2019
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Ingår i: Clinical Nuclear Medicine. - : Lippincott Williams & Wilkins. - 0363-9762 .- 1536-0229. ; 44:8, s. 655-656
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- We report a case of a transient focal MIBI uptake in the late, 90 minutes postinjection phase of a parathyroid scintigraphy in which SPECT/CT imaging proved valuable in delineating the nature of this incidental finding.
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| 26. |
- Simard, Trevor, et al.
(författare)
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Impact of Center Experience on Patient Radiation Exposure During Transradial Coronary Angiography and Percutaneous Intervention : A Patient-Level, International, Collaborative, Multi-Center Analysis
- 2016
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Ingår i: Journal of the American Heart Association. - Hoboken, USA : Wiley-Blackwell. - 2047-9980. ; 5:6
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Tidskriftsartikel (refereegranskat)abstract
- Background: The adoption of the transradial (TR) approach over the traditional transfemoral (TF) approach has been hampered by concerns of increased radiation exposure-a subject of considerable debate within the field. We performed a patient-level, multi-center analysis to definitively address the impact of TR access on radiation exposure.Methods and Results: Overall, 10 centers were included from 6 countries-Canada (2 centers), United Kingdom (2), Germany (2), Sweden (2), Hungary (1), and The Netherlands (1). We compared the radiation exposure of TR versus TF access using measured dose-area product (DAP). To account for local variations in equipment and exposure, standardized TR:TF DAP ratios were constructed per center with procedures separated by coronary angiography (CA) and percutaneous coronary intervention (PCI). Among 57 326 procedures, we demonstrated increased radiation exposure with the TR versus TF approach, particularly in the CA cohort across all centers (weighted-average ratios: CA, 1.15; PCI, 1.05). However, this was mitigated by increasing TR experience in the PCI cohort across all centers (r=-0.8; P=0.005). Over time, as a center transitioned to increasing TR experience (r=0.9; P=0.001), a concomitant decrease in radiation exposure occurred (r=-0.8; P=0.006). Ultimately, when a center's balance of TR to TF procedures approaches 50%, the resultant radiation exposure was equivalent.Conclusions: The TR approach is associated with a modest increase in patient radiation exposure. However, this increase is eliminated when the TR and TF approaches are used with equal frequency-a guiding principle for centers adopting the TR approach.
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