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Kataria, B., Nilsson Althen, J., Smedby, Ö., Persson, A., Sökjer, H. & Sandborg, M. (2019). Image quality and pathology assessment in CT Urography: when is the low-dose seriessufficient?. BMC Medical Imaging, 19, Article ID 64.
Åpne denne publikasjonen i ny fane eller vindu >>Image quality and pathology assessment in CT Urography: when is the low-dose seriessufficient?
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2019 (engelsk)Inngår i: BMC Medical Imaging, ISSN 1471-2342, E-ISSN 1471-2342, Vol. 19, artikkel-id 64Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Background

Our aim was to compare CT images from native, nephrographic and excretory phases using image quality criteria as well as the detection of positive pathological findings in CT Urography, to explore if the radiation burden to the younger group of patients or patients with negative outcomes can be reduced.

Methods

This is a retrospective study of 40 patients who underwent a CT Urography examination on a 192-slice dual source scanner. Image quality was assessed for four specific renal image criteria from the European guidelines, together with pathological assessment in three categories: renal, other abdominal, and incidental findings without clinical significance. Each phase was assessed individually by three radiologists with varying experience using a graded scale. Certainty scores were derived based on the graded assessments. Statistical analysis was performed using visual grading regression (VGR). The limit for significance was set at p = 0.05.

Results

For visual reproduction of the renal parenchyma and renal arteries, the image quality was judged better for the nephrogram phase (p < 0.001), whereas renal pelvis/calyces and proximal ureters were better reproduced in the excretory phase compared to the native phase (p < 0.001). Similarly, significantly higher certainty scores were obtained in the nephrogram phase for renal parenchyma and renal arteries, but in the excretory phase for renal pelvis/calyxes and proximal ureters. Assessment of pathology in the three categories showed no statistically significant differences between the three phases. Certainty scores for assessment of pathology, however, showed a significantly higher certainty for renal pathology when comparing the native phase to nephrogram and excretory phase and a significantly higher score for nephrographic phase but only for incidental findings.

Conclusion

Visualisation of renal anatomy was as expected with each post-contrast phase showing favourable scores compared to the native phase. No statistically significant differences in the assessment of pathology were found between the three phases. The low-dose CT (LDCT) seems to be sufficient in differentiating between normal and pathological examinations. To reduce the radiation burden in certain patient groups, the LDCT could be considered a suitable alternative as a first line imaging method. However, radiologists should be aware of its limitations.

sted, utgiver, år, opplag, sider
BioMed Central, 2019
Emneord
Computed tomography, Urography, Low-dose, Optimization, Image quality, Dose
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-159965 (URN)10.1186/s12880-019-0363-z (DOI)000480486200001 ()31399078 (PubMedID)2-s2.0-85070460822 (Scopus ID)
Prosjekter
Visual grading evaluation of reconstruction methods and dose optimisation in abdominal Computed Tomography
Forskningsfinansiär
Region Östergötland, LIO-620341Linköpings universitet, LIO-697941
Tilgjengelig fra: 2019-08-30 Laget: 2019-08-30 Sist oppdatert: 2019-09-04bibliografisk kontrollert
Kataria, B., Nilsson Althen, J., Smedby, Ö., Persson, A., Sökjer, H. & Sandborg, M. (2018). Assessment of image quality in abdominal CT: potential dose reduction with model-based iterative reconstruction. European Radiology
Åpne denne publikasjonen i ny fane eller vindu >>Assessment of image quality in abdominal CT: potential dose reduction with model-based iterative reconstruction
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2018 (engelsk)Inngår i: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Purpose To estimate potential dose reduction in abdominal CT by visually comparing images reconstructed with filtered back projection (FBP) and strengths of 3 and 5 of a specific MBIR.

Material and methods A dual-source scanner was used to obtain three data sets each for 50 recruited patients with 30, 70 and 100% tube loads (mean CTDIvol 1.9, 3.4 and 6.2 mGy). Six image criteria were assessed independently by five radiologists. Potential dose reduction was estimated with Visual Grading Regression (VGR).

Results Comparing 30 and 70% tube load, improved image quality was observed as a significant strong effect of log tube load and reconstruction method with potential dose reduction relative to FBP of 22–47% for MBIR strength 3 (p < 0.001). For MBIR strength 5 no dose reduction was possible for image criteria 1 (liver parenchyma), but dose reduction between 34 and 74% was achieved for other criteria. Interobserver reliability showed agreement of 71–76% (κw 0.201–0.286) and intra-observer reliability of 82–96% (κw 0.525–0.783).

Conclusion MBIR showed improved image quality compared to FBP with positive correlation between MBIR strength and increasing potential dose reduction for all but one image criterion.

sted, utgiver, år, opplag, sider
Heidelberg: Springer, 2018
Emneord
Dose Computed tomography Iterative reconstruction Abdomen FBP
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-145274 (URN)10.1007/s00330-017-5113-4 (DOI)000431653200023 ()29368163 (PubMedID)2-s2.0-85040915759 (Scopus ID)
Merknad

Funding agencies: ALF-grant from Region Ostergotland; LFoU-grant from Region Ostergotland; Medical Faculty at Linkoping University

Tilgjengelig fra: 2018-02-20 Laget: 2018-02-20 Sist oppdatert: 2019-09-01bibliografisk kontrollert
Siiskonen, T., Ciraj-Bjelac, O., Dabin, J., Diklic, A., Domienik-Andrzejewska, J., Farah, J., . . . Vano, E. (2018). Establishing the European diagnostic reference levels for interventional cardiology. Physica medica (Testo stampato), 54, 42-48
Åpne denne publikasjonen i ny fane eller vindu >>Establishing the European diagnostic reference levels for interventional cardiology
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2018 (engelsk)Inngår i: Physica medica (Testo stampato), ISSN 1120-1797, E-ISSN 1724-191X, Vol. 54, s. 42-48Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Interventional cardiac procedures may be associated with high patient doses and therefore require special attention to protect the patients from radiation injuries such as skin erythema, cardiovascular tissue reactions or radiation-induced cancer. In this study, patient exposure data is collected from 13 countries (37 clinics and nearly 50 interventional rooms) and for 10 different procedures. Dose data was collected from a total of 14,922 interventional cardiology procedures. Based on these data European diagnostic reference levels (DRL) for air kerma-area product are suggested for coronary angiography (CA, DRL = 35 Gy cm(2)), percutaneous coronary intervention (PCI, 85 Gy cm(2)), transcatheter aortic valve implantation (TAVI, 130 Gy cm(2)), electrophysiological procedures (12 Gy cm(2)) and pacemaker implantations Pacemaker implantations were further divided into single-chamber (2.5 Gy cm(2)) and dual chamber (3.5 Gy cm(2)) procedures and implantations of cardiac resynchronization therapy pacemaker (18 Gy cm(2)). Results show that relatively new techniques such as TAVI and treatment of chronic total occlusion (CTO) often produce relatively high doses, and thus emphasises the need for use of an optimization tool such as DRL to assist in reducing patient exposure. The generic DRL presented here facilitate comparison of patient exposure in interventional cardiology.

sted, utgiver, år, opplag, sider
ELSEVIER SCI LTD, 2018
Emneord
Diagnostic reference levels; Interventional cardiology
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-152392 (URN)10.1016/j.ejmp.2018.09.012 (DOI)000447271300006 ()30337009 (PubMedID)
Tilgjengelig fra: 2018-10-30 Laget: 2018-10-30 Sist oppdatert: 2019-05-01
Malusek, A., Sandborg, M. & Alm Carlsson, G. (2016). ACCURATE KAP METER CALIBRATION AS A PREREQUISITE FOR OPTIMISATION IN PROJECTION RADIOGRAPHY. Radiation Protection Dosimetry, 169(1-4), 353-359
Åpne denne publikasjonen i ny fane eller vindu >>ACCURATE KAP METER CALIBRATION AS A PREREQUISITE FOR OPTIMISATION IN PROJECTION RADIOGRAPHY
2016 (engelsk)Inngår i: Radiation Protection Dosimetry, ISSN 0144-8420, E-ISSN 1742-3406, Vol. 169, nr 1-4, s. 353-359Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Modern X-ray units register the air kerma–area product, PKA, with a built-in KAP meter. Some KAP meters show an energydependent bias comparable with the maximum uncertainty articulated by the IEC (25 %), adversely affecting dose-optimisation processes. To correct for the bias, a reference KAP meter calibrated at a standards laboratory and two calibration methods described here can be used to achieve an uncertainty of <7 % as recommended by IAEA. A computational model of the reference KAP meter is used to calculate beam quality correction factors for transfer of the calibration coefficient at the standards laboratory, Q0, to any beam quality, Q, in the clinic. Alternatively, beam quality corrections are measured with an energy-independent dosemeter via a reference beam quality in the clinic, Q1, to beam quality, Q. Biases up to 35 % of built-in KAP meter readings were noted. Energy-dependent calibration factors are needed for unbiased PKA. Accurate KAP meter calibration as a prerequisite for optimisation in projection radiography.

sted, utgiver, år, opplag, sider
Oxford University Press, 2016
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-124662 (URN)10.1093/rpd/ncv524 (DOI)000383492100056 ()26743261 (PubMedID)
Merknad

Funding agencies: Swedish Radiation Safety Authority, SSM [SSM 2014-1204]

Tilgjengelig fra: 2016-02-09 Laget: 2016-02-09 Sist oppdatert: 2017-05-02bibliografisk kontrollert
Tesselaar, E. & Sandborg, M. (2016). ASSESSING THE USEFULNESS OF THE QUASI-IDEAL OBSERVER FORQUALITY CONTROL IN FLUOROSCOPY. Radiation Protection Dosimetry, 169(1-4), 360-364
Åpne denne publikasjonen i ny fane eller vindu >>ASSESSING THE USEFULNESS OF THE QUASI-IDEAL OBSERVER FORQUALITY CONTROL IN FLUOROSCOPY
2016 (engelsk)Inngår i: Radiation Protection Dosimetry, ISSN 0144-8420, E-ISSN 1742-3406, Vol. 169, nr 1-4, s. 360-364Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The aim of this work was to evaluate the reliability of the square of the signal-to-noise ratio rate, SNR2rate, as a precise measurement for quality control test in a digital fluoroscopy system. The quasi-ideal model observer was used to measure SNR2rate. The dose rate, pulse rate and field of view were varied, and their effect on dose efficiency, defined as SNR2rate=PKA;rate, was evaluated (where PKA;rate is the air kerma-area product rate). Measurements were repeated to assess reproducibility. The relative standard deviation in SNR2rate=PKA;rate over seven consecutive measurements was 5 %. No significant variation in SNR2rate=PKA;rate was observed across different pulse rates (10–30 pulses s-1). The low-dose-rate setting had a superior dose efficiency compared with the medium- and high-dose-rate settings. A smaller field of view resulted in higher dose efficiency. The results show that SNR2rate=PKA;rate measurements offer the high precision required in quality control constancy tests.

HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-123020 (URN)10.1093/rpd/ncv434 (DOI)000383492100057 ()26493947 (PubMedID)
Merknad

Funding agencies: ALF (Avtal om Lakarutbildning och Forskning) grants from Region Ostergotland [LIO-357651]

Tilgjengelig fra: 2015-12-02 Laget: 2015-12-02 Sist oppdatert: 2017-12-01bibliografisk kontrollert
Kardell, M., Magnusson, M., Sandborg, M., Alm Carlsson, G., Jeuthe, J. & Malusek, A. (2016). AUTOMATIC SEGMENTATION OF PELVIS FOR BRACHYTHERAPYOF PROSTATE. Radiation Protection Dosimetry, 169(1-4), 398-404
Åpne denne publikasjonen i ny fane eller vindu >>AUTOMATIC SEGMENTATION OF PELVIS FOR BRACHYTHERAPYOF PROSTATE
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2016 (engelsk)Inngår i: Radiation Protection Dosimetry, ISSN 0144-8420, E-ISSN 1742-3406, Vol. 169, nr 1-4, s. 398-404Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Advanced model-based iterative reconstruction algorithms in quantitative computed tomography (CT) perform automatic segmentation of tissues to estimate material properties of the imaged object. Compared with conventional methods, these algorithms may improve quality of reconstructed images and accuracy of radiation treatment planning. Automatic segmentation of tissues is, however, a difficult task. The aim of this work was to develop and evaluate an algorithm that automatically segments tissues in CT images of the male pelvis. The newly developed algorithm (MK2014) combines histogram matching, thresholding, region growing, deformable model and atlas-based registration techniques for the segmentation of bones, adipose tissue, prostate and muscles in CT images. Visual inspection of segmented images showed that the algorithm performed well for the five analysed images. The tissues were identified and outlined with accuracy sufficient for the dual-energy iterative reconstruction algorithm whose aim is to improve the accuracy of radiation treatment planning in brachytherapy of the prostate.

HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-122978 (URN)10.1093/rpd/ncv461 (DOI)000383492100063 ()26567322 (PubMedID)
Forskningsfinansiär
Swedish Cancer Society, CAN 2012/764Swedish Cancer Society, CAN 2014/691
Merknad

Funding agencies: Swedish Cancer Foundation [CAN 2012/764, CAN 2014/691]; Medical Faculty, Linkoping University; ALF Grants, Region Ostergotland [LiO-438731]

Tilgjengelig fra: 2015-12-01 Laget: 2015-12-01 Sist oppdatert: 2017-12-01
Tesselaar, E., Dahlström, N. & Sandborg, M. (2016). CLINICAL AUDIT OF IMAGE QUALITY IN RADIOLOGY USING VISUAL GRADING CHARACTERISTICS ANALYSIS. Radiation Protection Dosimetry, 169(1-4), 340-346
Åpne denne publikasjonen i ny fane eller vindu >>CLINICAL AUDIT OF IMAGE QUALITY IN RADIOLOGY USING VISUAL GRADING CHARACTERISTICS ANALYSIS
2016 (engelsk)Inngår i: Radiation Protection Dosimetry, ISSN 0144-8420, E-ISSN 1742-3406, Vol. 169, nr 1-4, s. 340-346Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The aim of this work was to assess whether an audit of clinical image quality could be efficiently implemented within a limited time frame using visual grading characteristics (VGC) analysis. Lumbar spine radiography, bedside chest radiography and abdominal CT were selected. For each examination, images were acquired or reconstructed in two ways. Twenty images per examination were assessed by 40 radiology residents using visual grading of image criteria. The results were analysed using VGC. Inter-observer reliability was assessed. The results of the visual grading analysis were consistent with expected outcomes. The inter-observer reliability was moderate to good and correlated with perceived image quality (r2 5 0.47). The median observation time per image or image series was within 2 min. These results suggest that the use of visual grading of image criteria to assess the quality of radiographs provides a rapid method for performing an image quality audit in a clinical environment.

HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-123019 (URN)10.1093/rpd/ncv411 (DOI)000383492100054 ()26410763 (PubMedID)
Tilgjengelig fra: 2015-12-02 Laget: 2015-12-02 Sist oppdatert: 2017-05-03
Simard, T., Hibbert, B., Natarjan, M., Mercuri, M., Hetherington, S., Wright, R., . . . So, D. (2016). Impact of Center Experience on Patient Radiation Exposure During Transradial Coronary Angiography and Percutaneous Intervention: A Patient-Level, International, Collaborative, Multi-Center Analysis. Journal of the American Heart Association: Cardiovascular and Cerebrovascular Disease, 5(6)
Åpne denne publikasjonen i ny fane eller vindu >>Impact of Center Experience on Patient Radiation Exposure During Transradial Coronary Angiography and Percutaneous Intervention: A Patient-Level, International, Collaborative, Multi-Center Analysis
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2016 (engelsk)Inngår i: Journal of the American Heart Association: Cardiovascular and Cerebrovascular Disease, ISSN 2047-9980, E-ISSN 2047-9980, Vol. 5, nr 6Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

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.

sted, utgiver, år, opplag, sider
Wiley-Blackwell, 2016
Emneord
coronary angiography, dose-area product, percutaneous coronary intervention, radial artery catheterisation, radiation, transradial
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-129002 (URN)10.1161/JAHA.116.003333 (DOI)000386712700040 ()27247332 (PubMedID)
Merknad

Funding agencies: General Electric (GE) Healthcare; TeraRecon Inc.; Saul and Edna Goldfarb Research Chair in Cardiac Imaging

Tilgjengelig fra: 2016-06-08 Laget: 2016-06-08 Sist oppdatert: 2017-11-30
Kataria, B., Sandborg, M. & Nilsson Althen, J. (2016). IMPLICATIONS OF PATIENT CENTRING ON ORGAN DOSE IN COMPUTED TOMOGRAPHY. Radiation Protection Dosimetry, 169(1-4), 130-135
Åpne denne publikasjonen i ny fane eller vindu >>IMPLICATIONS OF PATIENT CENTRING ON ORGAN DOSE IN COMPUTED TOMOGRAPHY
2016 (engelsk)Inngår i: Radiation Protection Dosimetry, ISSN 0144-8420, E-ISSN 1742-3406, Vol. 169, nr 1-4, s. 130-135Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Automatic exposure control (AEC) in computed tomography (CT) facilitates optimisation of dose absorbed by the patient. The use of AEC requires appropriate ‘patient centring’ within the gantry, since positioning the patient off-centre may affect both image quality and absorbed dose. The aim of this experimental study was to measure the variation in organ and abdominal surface dose during CTexaminations of the head, neck/thorax and abdomen. The dose was compared at the isocenter with two off-centre positions—ventral and dorsal to the isocenter. Measurements were made with an anthropomorphic adult phantom and thermoluminescent dosemeters. Organs and surfaces for ventral regions received lesser dose (5.6–39.0 %) than the isocenter when the phantom was positioned 13 cm off-centre. Similarly, organ and surface doses for dorsal regions were reduced by 5.0–21.0 % at 25 cm off-centre. Therefore, correct vertical positioning of the patient at the gantry isocenter is important to maintain optimal imaging conditions.

sted, utgiver, år, opplag, sider
Oxford University Press, 2016
Emneord
computed tomography, organ dose
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-125340 (URN)10.1093/rpd/ncv527 (DOI)000383492100020 ()26743256 (PubMedID)
Tilgjengelig fra: 2016-02-19 Laget: 2016-02-19 Sist oppdatert: 2019-09-01
Örtenberg, A., Magnusson, M., Sandborg, M., Alm Carlsson, G. & Malusek, A. (2016). PARALLELISATION OF THE MODEL-BASED ITERATIVE RECONSTRUCTION ALGORITHM DIRA. Radiation Protection Dosimetry, 169(1-4), 405-409
Åpne denne publikasjonen i ny fane eller vindu >>PARALLELISATION OF THE MODEL-BASED ITERATIVE RECONSTRUCTION ALGORITHM DIRA
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2016 (engelsk)Inngår i: Radiation Protection Dosimetry, ISSN 0144-8420, E-ISSN 1742-3406, Vol. 169, nr 1-4, s. 405-409Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

New paradigms for parallel programming have been devised to simplify software development on multi-core processors and many-core graphical processing units (GPU). Despite their obvious benefits, the parallelisation of existing computer programs is not an easy task. In this work, the use of the Open Multiprocessing (OpenMP) and Open Computing Language (OpenCL) frameworks is considered for the parallelisation of the model-based iterative reconstruction algorithm DIRA with the aim to significantly shorten the code’s execution time. Selected routines were parallelised using OpenMP and OpenCL libraries; some routines were converted from MATLAB to C and optimised. Parallelisation of the code with the OpenMP was easy and resulted in an overall speedup of 15 on a 16-core computer. Parallelisation with OpenCL was more difficult owing to differences between the central processing unit and GPU architectures. The resulting speedup was substantially lower than the theoretical peak performance of the GPU; the cause was explained.

sted, utgiver, år, opplag, sider
Oxford university press: , 2016
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-123009 (URN)10.1093/rpd/ncv430 (DOI)000383492100064 ()26454270 (PubMedID)
Forskningsfinansiär
Swedish Cancer Society, CAN 2012/764Swedish Cancer Society, CAN 2014/691
Merknad

Funding agencies: Swedish Cancer Foundation [CAN 2012/764, CAN 2014/691]

Tilgjengelig fra: 2015-12-01 Laget: 2015-12-01 Sist oppdatert: 2018-01-10
Organisasjoner
Identifikatorer
ORCID-id: ORCID iD iconorcid.org/0000-0003-3352-8330