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Smedby, Örjan, ProfessorORCID iD iconorcid.org/0000-0002-7750-1917
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Kataria, B., Nilsson Althén, J., Smedby, Ö., Persson, A., Sökjer-Petersen, H. & Sandborg, M. (2019). Image quality and pathology assessment in CT Urography: when is the low-dose series sufficient?. BMC Medical Imaging, 19(1), Article ID 64.
Öppna denna publikation i ny flik eller fönster >>Image quality and pathology assessment in CT Urography: when is the low-dose series sufficient?
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2019 (Engelska)Ingår i: BMC Medical Imaging, ISSN 1471-2342, E-ISSN 1471-2342, Vol. 19, nr 1, artikel-id 64Artikel i tidskrift (Refereegranskat) 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.

Ort, förlag, år, upplaga, sidor
BioMed Central, 2019
Nyckelord
Computed tomography; Urography; Low-dose; Optimization; Image quality; Dose
Nationell ämneskategori
Radiologi och bildbehandling
Identifikatorer
urn:nbn:se:liu:diva-160048 (URN)10.1186/s12880-019-0363-z (DOI)000480486200001 ()31399078 (PubMedID)2-s2.0-85070460822 (Scopus ID)
Anmärkning

Funding Agencies|ALF-and LFoU-grants from Region Ostergotland; Medical Faculty at Linkoping University

Tillgänglig från: 2019-09-06 Skapad: 2019-09-06 Senast uppdaterad: 2019-10-15Bibliografiskt granskad
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
Öppna denna publikation i ny flik eller fönster >>Assessment of image quality in abdominal CT: potential dose reduction with model-based iterative reconstruction
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2018 (Engelska)Ingår i: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084Artikel i tidskrift (Refereegranskat) 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.

Ort, förlag, år, upplaga, sidor
Heidelberg: Springer, 2018
Nyckelord
Dose Computed tomography Iterative reconstruction Abdomen FBP
Nationell ämneskategori
Radiologi och bildbehandling
Identifikatorer
urn:nbn:se:liu:diva-145274 (URN)10.1007/s00330-017-5113-4 (DOI)000431653200023 ()29368163 (PubMedID)2-s2.0-85040915759 (Scopus ID)
Anmärkning

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

Tillgänglig från: 2018-02-20 Skapad: 2018-02-20 Senast uppdaterad: 2019-10-15Bibliografiskt granskad
Klintström, B., Klintström, E., Smedby, Ö. & Moreno, R. (2017). Feature space clustering for trabecular bone segmentation. In: Sharma P., Bianchi F. (Ed.), Image Analysis - 20th Scandinavian Conference on Image Analysis, SCIA 2017, Proceedings: . Paper presented at 20th Scandinavian Conference on Image Analysis (SCIA), Tromsö 12-14 juni 2017 (pp. 65-70). Springer, 10270
Öppna denna publikation i ny flik eller fönster >>Feature space clustering for trabecular bone segmentation
2017 (Engelska)Ingår i: Image Analysis - 20th Scandinavian Conference on Image Analysis, SCIA 2017, Proceedings / [ed] Sharma P., Bianchi F., Springer, 2017, Vol. 10270, s. 65-70Konferensbidrag, Publicerat paper (Refereegranskat)
Abstract [en]

Trabecular bone structure has been shown to impact bone strength and fracture risk. In vitro, this structure can be measured by micro-computed tomography (micro-CT). For clinical use, it would be valuable if multi-slice computed tomography (MSCT) could be used to analyse trabecular bone structure. One important step in the analysis is image volume segmentation. Previous segmentation techniques have either been computer resource intensive or produced suboptimal results when used on MSCT data. This paper proposes a new segmentation method that tries to balance good results against computational complexity.

Ort, förlag, år, upplaga, sidor
Springer, 2017
Serie
Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349 ; 10270
Nyckelord
Clustering, Feature-space, Segmentation, Trabecular bone
Nationell ämneskategori
Radiologi och bildbehandling
Identifikatorer
urn:nbn:se:liu:diva-142938 (URN)10.1007/978-3-319-59129-2_6 (DOI)978-3-319-59128-5 (ISBN)978-3-319-59129-2 (ISBN)
Konferens
20th Scandinavian Conference on Image Analysis (SCIA), Tromsö 12-14 juni 2017
Tillgänglig från: 2017-11-13 Skapad: 2017-11-13 Senast uppdaterad: 2018-03-26
Chowdhury, M., Klintström, B., Klintström, E., Smedby, Ö. & Moreno, R. (2017). Granulometry-Based Trabecular Bone Segmentation. In: Sharma P., Bianchi F. (Ed.), Image Analysis - 20th Scandinavian Conference on Image Analysis, SCIA 2017, Proceedings: . Paper presented at 20th Scandinavian Conference on Image Analysis (SCIA), Tromsö 12-14 juni 2017 (pp. 100-108). Springer, 10270
Öppna denna publikation i ny flik eller fönster >>Granulometry-Based Trabecular Bone Segmentation
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2017 (Engelska)Ingår i: Image Analysis - 20th Scandinavian Conference on Image Analysis, SCIA 2017, Proceedings / [ed] Sharma P., Bianchi F., Springer, 2017, Vol. 10270, s. 100-108Konferensbidrag, Publicerat paper (Refereegranskat)
Abstract [en]

The accuracy of the analyses for studying the three dimensionaltrabecular bone microstructure rely on the quality of the segmentationbetween trabecular bone and bone marrow. Such segmentationis challenging for images from computed tomography modalities thatcan be used in vivo due to their low contrast and resolution. For thispurpose, we propose in this paper a granulometry-based segmentationmethod. In a first step, the trabecular thickness is estimated by usingthe granulometry in gray scale, which is generated by applying the openingmorphological operation with ball-shaped structuring elements ofdifferent diameters. This process mimics the traditional sphere-fittingmethod used for estimating trabecular thickness in segmented images.The residual obtained after computing the granulometry is comparedto the original gray scale value in order to obtain a measurement ofhow likely a voxel belongs to trabecular bone. A threshold is applied toobtain the final segmentation. Six histomorphometric parameters werecomputed on 14 segmented bone specimens imaged with cone-beam computedtomography (CBCT), considering micro-computed tomography(micro-CT) as the ground truth. Otsu’s thresholding and AutomatedRegion Growing (ARG) segmentation methods were used for comparison.For three parameters (Tb.N, Tb.Th and BV/TV), the proposedsegmentation algorithm yielded the highest correlations with micro-CT,while for the remaining three (Tb.Nd, Tb.Tm and Tb.Sp), its performancewas comparable to ARG. The method also yielded the strongestaverage correlation (0.89). When Tb.Th was computed directly fromthe gray scale images, the correlation was superior to the binary-basedmethods. The results suggest that the proposed algorithm can be usedfor studying trabecular bone in vivo through CBCT.

Ort, förlag, år, upplaga, sidor
Springer, 2017
Serie
Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349 ; 10270
Nyckelord
Cone beam computed tomography; Segmentation; Granulometry; Trabecular bone
Nationell ämneskategori
Radiologi och bildbehandling
Identifikatorer
urn:nbn:se:liu:diva-142961 (URN)10.1007/978-3-319-59129-2_9 (DOI)
Konferens
20th Scandinavian Conference on Image Analysis (SCIA), Tromsö 12-14 juni 2017
Tillgänglig från: 2017-11-13 Skapad: 2017-11-13 Senast uppdaterad: 2018-04-03Bibliografiskt granskad
Lidayova, K., Frimmel, H., Wang, C., Bengtsson, E. & Smedby, Ö. (2016). Fast vascular skeleton extraction algorithm. Pattern Recognition Letters, 76, 67-75
Öppna denna publikation i ny flik eller fönster >>Fast vascular skeleton extraction algorithm
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2016 (Engelska)Ingår i: Pattern Recognition Letters, ISSN 0167-8655, E-ISSN 1872-7344, Vol. 76, s. 67-75Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Vascular diseases are a common cause of death, particularly in developed countries. Computerized image analysis tools play a potentially important role in diagnosing and quantifying vascular pathologies. Given the size and complexity of modern angiographic data acquisition, fast, automatic and accurate vascular segmentation is a challenging task. In this paper we introduce a fully automatic high-speed vascular skeleton extraction algorithm that is intended as a first step in a complete vascular tree segmentation program. The method takes a 3D unprocessed Computed Tomography Angiography (CTA) scan as input and produces a graph in which the nodes are centrally located artery voxels and the edges represent connections between them. The algorithm works in two passes where the first pass is designed to extract the skeleton of large arteries and the second pass focuses on smaller vascular structures. Each pass consists of three main steps. The first step sets proper parameters automatically using Gaussian curve fitting. In the second step different filters are applied to detect voxels nodes - that are part of arteries. In the last step the nodes are connected in order to obtain a continuous centerline tree for the entire vasculature. Structures found, that do not belong to the arteries, are removed in a final anatomy-based analysis. The proposed method is computationally efficient with an average execution time of 29 s and has been tested on a set of CTA scans of the lower limbs achieving an average overlap rate of 97% and an average detection rate of 71%. (C) 2015 Elsevier B.V. All rights reserved.

Ort, förlag, år, upplaga, sidor
ELSEVIER SCIENCE BV, 2016
Nyckelord
Skeleton extraction; Centerline tree; Vascular tree; Blood vessels; CT angiography
Nationell ämneskategori
Klinisk medicin
Identifikatorer
urn:nbn:se:liu:diva-128720 (URN)10.1016/j.patrec.2015.06.024 (DOI)000375135600009 ()
Anmärkning

Funding Agencies|Swedish Council for Research [VR-NT 2014-6153]

Tillgänglig från: 2016-06-07 Skapad: 2016-05-30 Senast uppdaterad: 2017-11-30
Maria Marreiros, F. M., Wang, C., Rossitti, S. & Smedby, Ö. (2016). Non-rigid point set registration of curves: registration of the superficial vessel centerlines of the brain. In: Medical Imaging 2016: Image-Guided Procedures, Robotic Interventions, and Modeling. Paper presented at Medical Imaging 2016: Image-Guided Procedures, Robotic Interventions, and Modeling, San Diego, California, United States, February 27, 2016 (pp. 978611-1-978611-8). SPIE - International Society for Optical Engineering, 9786
Öppna denna publikation i ny flik eller fönster >>Non-rigid point set registration of curves: registration of the superficial vessel centerlines of the brain
2016 (Engelska)Ingår i: Medical Imaging 2016: Image-Guided Procedures, Robotic Interventions, and Modeling, SPIE - International Society for Optical Engineering, 2016, Vol. 9786, s. 8s. 978611-1-978611-8Konferensbidrag, Publicerat paper (Refereegranskat)
Abstract [en]

In this study we present a non-rigid point set registration for 3D curves (composed by 3D set of points). Themethod was evaluated in the task of registration of 3D superficial vessels of the brain where it was used to matchvessel centerline points. It consists of a combination of the Coherent Point Drift (CPD) and the Thin-PlateSpline (TPS) semilandmarks. The CPD is used to perform the initial matching of centerline 3D points, whilethe semilandmark method iteratively relaxes/slides the points.

For the evaluation, a Magnetic Resonance Angiography (MRA) dataset was used. Deformations were appliedto the extracted vessels centerlines to simulate brain bulging and sinking, using a TPS deformation where afew control points were manipulated to obtain the desired transformation (T1). Once the correspondences areknown, the corresponding points are used to define a new TPS deformation(T2). The errors are measured in thedeformed space, by transforming the original points using T1 and T2 and measuring the distance between them.To simulate cases where the deformed vessel data is incomplete, parts of the reference vessels were cut and thendeformed. Furthermore, anisotropic normally distributed noise was added.

The results show that the error estimates (root mean square error and mean error) are below 1 mm, even inthe presence of noise and incomplete data.

Ort, förlag, år, upplaga, sidor
SPIE - International Society for Optical Engineering, 2016. s. 8
Serie
Progress in Biomedical Optics, ISSN 1605-7422 ; 9786
Nyckelord
Non-rigid registration, brain shift correction, vessel registration
Nationell ämneskategori
Medicinsk bildbehandling
Identifikatorer
urn:nbn:se:liu:diva-126347 (URN)10.1117/12.2208421 (DOI)000382315800036 ()978-1-5106-0021-8 (ISBN)
Konferens
Medical Imaging 2016: Image-Guided Procedures, Robotic Interventions, and Modeling, San Diego, California, United States, February 27, 2016
Projekt
ARIOR
Forskningsfinansiär
Barncancerfonden, MT2013-0036
Tillgänglig från: 2016-03-22 Skapad: 2016-03-22 Senast uppdaterad: 2016-09-27Bibliografiskt granskad
Klintström, E., Klintström, B., Moreno, R., Brismar, T. B., Pahr, D. H. & Smedby, Ö. (2016). Predicting Trabecular Bone Stiffness from Clinical Cone-Beam CT and HR-pQCT Data; an In Vitro Study Using Finite Element Analysis. PLoS ONE, 11(8), Article ID e0161101.
Öppna denna publikation i ny flik eller fönster >>Predicting Trabecular Bone Stiffness from Clinical Cone-Beam CT and HR-pQCT Data; an In Vitro Study Using Finite Element Analysis
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2016 (Engelska)Ingår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, nr 8, artikel-id e0161101Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Stiffness and shear moduli of human trabecular bone may be analyzed in vivo by finite element (FE) analysis from image data obtained by clinical imaging equipment such as high resolution peripheral quantitative computed tomography (HR-pQCT). In clinical practice today, this is done in the peripheral skeleton like the wrist and heel. In this cadaveric bone study, fourteen bone specimens from the wrist were imaged by two dental cone beam computed tomography (CBCT) devices and one HR-pQCT device as well as by dual energy X-ray absorptiometry (DXA). Histomorphometric measurements from micro-CT data were used as gold standard. The image processing was done with an in-house developed code based on the automated region growing (ARG) algorithm. Evaluation of how well stiffness (Young’s modulus E3) and minimum shear modulus from the 12, 13, or 23 could be predicted from the CBCT and HR-pQCT imaging data was studied and compared to FE analysis from the micro-CT imaging data. Strong correlations were found between the clinical machines and micro-CT regarding trabecular bone structure parameters, such as bone volume over total volume, trabecular thickness, trabecular number and trabecular nodes (varying from 0.79 to 0.96). The two CBCT devices as well as the HR-pQCT showed the ability to predict stiffness and shear, with adjusted R2 -values between 0.78 and 0.92, based on data derived through our in-house developed code based on the ARG algorithm. These findings indicate that clinically used CBCT may be a feasible method for clinical studies of bone structure and mechanical properties in future osteoporosis research.

Ort, förlag, år, upplaga, sidor
Public library of science, 2016
Nationell ämneskategori
Klinisk medicin
Identifikatorer
urn:nbn:se:liu:diva-130798 (URN)10.1371/journal.pone.0161101 (DOI)000381381100120 ()27513664 (PubMedID)
Tillgänglig från: 2016-08-24 Skapad: 2016-08-24 Senast uppdaterad: 2018-03-26Bibliografiskt granskad
Blystad, I., Håkansson, I., Tisell, A., Ernerudh, J., Smedby, Ö., Lundberg, P. & Larsson, E.-M. (2016). Quantitative MRI for Analysis of Active Multiple Sclerosis Lesions without Gadolinium-Based Contrast Agent. American Journal of Neuroradiology, 37(1), 94-100
Öppna denna publikation i ny flik eller fönster >>Quantitative MRI for Analysis of Active Multiple Sclerosis Lesions without Gadolinium-Based Contrast Agent
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2016 (Engelska)Ingår i: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 37, nr 1, s. 94-100Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

BACKGROUND AND PURPOSE: Contrast-enhancing MS lesions are important markers of active inflammation in the diagnostic work-up of MS and in disease monitoring with MR imaging. Because intravenous contrast agents involve an expense and a potential risk of adverse events, it would be desirable to identify active lesions without using a contrast agent. The purpose of this study was to evaluate whether pre-contrast injection tissue-relaxation rates and proton density of MS lesions, by using a new quantitative MR imaging sequence, can identify active lesions. MATERIALS AND METHODS: Forty-four patients with a clinical suspicion of MS were studied. MR imaging with a standard clinical MS protocol and a quantitative MR imaging sequence was performed at inclusion (baseline) and after 1 year. ROIs were placed in MS lesions, classified as nonenhancing or enhancing. Longitudinal and transverse relaxation rates, as well as proton density were obtained from the quantitative MR imaging sequence. Statistical analyses of ROI values were performed by using a mixed linear model, logistic regression, and receiver operating characteristic analysis. RESULTS: Enhancing lesions had a significantly (P &lt; .001) higher mean longitudinal relaxation rate (1.22 0.36 versus 0.89 +/- 0.24), a higher mean transverse relaxation rate (9.8 +/- 2.6 versus 7.4 +/- 1.9), and a lower mean proton density (77 +/- 11.2 versus 90 +/- 8.4) than nonenhancing lesions. An area under the receiver operating characteristic curve value of 0.832 was obtained. CONCLUSIONS: Contrast-enhancing MS lesions often have proton density and relaxation times that differ from those in nonenhancing lesions, with lower proton density and shorter relaxation times in enhancing lesions compared with nonenhancing lesions.

Ort, förlag, år, upplaga, sidor
AMER SOC NEURORADIOLOGY, 2016
Nationell ämneskategori
Klinisk medicin
Identifikatorer
urn:nbn:se:liu:diva-124482 (URN)10.3174/ajnr.A4501 (DOI)000367466500019 ()26471751 (PubMedID)
Anmärkning

Funding Agencies|National Science and Engineering Research Council; University of Linkoping; University Hospital Research Funds

Tillgänglig från: 2016-02-02 Skapad: 2016-02-01 Senast uppdaterad: 2017-11-16
Bernard, O., Bosch, J. G., Heyde, B., Alessandrini, M., Barbosa, D., Camarasu-Pop, S., . . . Dhooge, J. (2016). Standardized Evaluation System for Left Ventricular Segmentation Algorithms in 3D Echocardiography. IEEE Transactions on Medical Imaging, 35(4), 967-977
Öppna denna publikation i ny flik eller fönster >>Standardized Evaluation System for Left Ventricular Segmentation Algorithms in 3D Echocardiography
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2016 (Engelska)Ingår i: IEEE Transactions on Medical Imaging, ISSN 0278-0062, E-ISSN 1558-254X, Vol. 35, nr 4, s. 967-977Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Real-time 3D Echocardiography (RT3DE) has been proven to be an accurate tool for left ventricular (LV) volume assessment. However, identification of the LV endocardium remains a challenging task, mainly because of the low tissue/blood contrast of the images combined with typical artifacts. Several semi and fully automatic algorithms have been proposed for segmenting the endocardium in RT3DE data in order to extract relevant clinical indices, but a systematic and fair comparison between such methods has so far been impossible due to the lack of a publicly available common database. Here, we introduce a standardized evaluation framework to reliably evaluate and compare the performance of the algorithms developed to segment the LV border in RT3DE. A database consisting of 45 multivendor cardiac ultrasound recordings acquired at different centers with corresponding reference measurements from three experts are made available. The algorithms from nine research groups were quantitatively evaluated and compared using the proposed online platform. The results showed that the best methods produce promising results with respect to the experts measurements for the extraction of clinical indices, and that they offer good segmentation precision in terms of mean distance error in the context of the experts variability range. The platform remains open for new submissions.

Ort, förlag, år, upplaga, sidor
IEEE Press, 2016
Nyckelord
Endocardium; left ventricle segmentation; real-time 3D echocardiography; standardized evaluation system
Nationell ämneskategori
Klinisk medicin
Identifikatorer
urn:nbn:se:liu:diva-127780 (URN)10.1109/TMI.2015.2503890 (DOI)000374164800004 ()26625409 (PubMedID)
Anmärkning

Funding agencies: Riksbankens Jubileumsfond; VINNOVA

Tillgänglig från: 2016-05-12 Skapad: 2016-05-12 Senast uppdaterad: 2017-11-30
Maria Marreiros, F. M., Rossitti, S., Karlsson, P., Wang, C., Gustafsson, T., Carleberg, P. & Smedby, Ö. (2016). Superficial vessel reconstruction with a multiview camera system. Journal of Medical Imaging, 3(1), 015001-1-015001-13
Öppna denna publikation i ny flik eller fönster >>Superficial vessel reconstruction with a multiview camera system
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2016 (Engelska)Ingår i: Journal of Medical Imaging, ISSN 2329-4302, E-ISSN 2329-4310, Vol. 3, nr 1, s. 015001-1-015001-13Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

We aim at reconstructing superficial vessels of the brain. Ultimately, they will serve to guide the deformationmethods to compensate for the brain shift. A pipeline for three-dimensional (3-D) vessel reconstructionusing three mono-complementary metal-oxide semiconductor cameras has been developed. Vessel centerlinesare manually selected in the images. Using the properties of the Hessian matrix, the centerline points areassigned direction information. For correspondence matching, a combination of methods was used. The processstarts with epipolar and spatial coherence constraints (geometrical constraints), followed by relaxation labelingand an iterative filtering where the 3-D points are compared to surfaces obtained using the thin-plate spline withdecreasing relaxation parameter. Finally, the points are shifted to their local centroid position. Evaluation invirtual, phantom, and experimental images, including intraoperative data from patient experiments, showsthat, with appropriate camera positions, the error estimates (root-mean square error and mean error) are∼1 mm.

Ort, förlag, år, upplaga, sidor
SPIE - International Society for Optical Engineering, 2016
Nationell ämneskategori
Datorseende och robotik (autonoma system)
Identifikatorer
urn:nbn:se:liu:diva-123661 (URN)10.1117/1.JMI.3.1.015001 (DOI)
Projekt
ARIOR
Forskningsfinansiär
Barncancerfonden, MT2013-0036
Tillgänglig från: 2016-01-05 Skapad: 2016-01-05 Senast uppdaterad: 2018-01-10Bibliografiskt granskad
Organisationer
Identifikatorer
ORCID-id: ORCID iD iconorcid.org/0000-0002-7750-1917

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