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Sousa, J. M., Appel, L., Engstrom, M., Nyholm, D., Ahlström, H. & Lubberink, M. (2024). Comparison of quantitative [11C]PE2I brain PET studies between an integrated PET/MR and a stand-alone PET system. Physica medica (Testo stampato), 117, Article ID 103185.
Open this publication in new window or tab >>Comparison of quantitative [11C]PE2I brain PET studies between an integrated PET/MR and a stand-alone PET system
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2024 (English)In: Physica medica (Testo stampato), ISSN 1120-1797, E-ISSN 1724-191X, Vol. 117, article id 103185Article in journal (Refereed) Published
Abstract [en]

PET/MR systems demanded great efforts for accurate attenuation correction (AC) but differences in technology, geometry and hardware attenuation may also affect quantitative results. Dedicated PET systems using transmission-based AC are regarded as the gold standard for quantitative brain PET. The study aim was to investigate the agreement between quantitative PET outcomes from a PET/MR scanner against a stand-alone PET system.Nine patients with Parkinsonism underwent two 80-min dynamic PET scans with the dopamine transporter ligand [11C]PE2I. Images were reconstructed with resolution-matched settings using 68Ge-transmission (standalone PET), and zero-echo-time MR (PET/MR) scans for AC. Non-displaceable binding potential (BPND) and relative delivery (R1) were evaluated using volumes of interest and voxel-wise analysis.Correlations between systems were high (r >= 0.85) for both quantitative outcome parameters in all brain regions. Striatal BPND was significantly lower on PET/MR than on stand-alone PET (-7%). R1 was significantly overestimated in posterior cortical regions (9%) and underestimated in striatal (-9%) and limbic areas (-6%). The voxel-wise evaluation revealed that the MR-safe headphones caused a negative bias in both parametric BPND and R1 images. Additionally, a significant positive bias of R1 was found in the auditory cortex, most likely due to the acoustic background noise during MR imaging. The relative bias of the quantitative [11C]PE2I PET data acquired from a SIGNA PET/MR system was in the same order as the expected test-retest reproducibility of [11C]PE2I BPND and R1, compared to a stand-alone ECAT PET scanner. MR headphones and background noise are potential sources of error in functional PET/MR studies.

Place, publisher, year, edition, pages
Elsevier, 2024
Keywords
Positron emission tomography, Dopamine transporter, Cerebral blood flow, PET quantification
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:uu:diva-520362 (URN)10.1016/j.ejmp.2023.103185 (DOI)001129803800001 ()38042064 (PubMedID)
Funder
Swedish Research Council, 2011-6269Swedish Research Council, 2016-01040Swedish Heart Lung Foundation, 20170492
Available from: 2024-01-15 Created: 2024-01-15 Last updated: 2024-01-15Bibliographically approved
Engström, G., Lampa, E., Dekkers, K., Lin, Y.-T., Ahlm, K., Ahlström, H., . . . Sundström, J. (2024). Pulmonary function and atherosclerosis in the general population: causal associations and clinical implications. Eur J Epidemiol
Open this publication in new window or tab >>Pulmonary function and atherosclerosis in the general population: causal associations and clinical implications
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2024 (English)In: Eur J Epidemiol, ISSN 1573-7284 Electronic 0393-2990 LinkingArticle in journal (Refereed) Published
Abstract [en]

Reduced lung function is associated with cardiovascular mortality, but the relationships with atherosclerosis are unclear. The population-based Swedish CArdioPulmonary BioImage study measured lung function, emphysema, coronary CT angiography, coronary calcium, carotid plaques and ankle-brachial index in 29,593 men and women aged 50-64 years. The results were confirmed using 2-sample Mendelian randomization. Lower lung function and emphysema were associated with more atherosclerosis, but these relationships were attenuated after adjustment for cardiovascular risk factors. Lung function was not associated with coronary atherosclerosis in 14,524 never-smokers. No potentially causal effect of lung function on atherosclerosis, or vice versa, was found in the 2-sample Mendelian randomization analysis. Here we show that reduced lung function and atherosclerosis are correlated in the population, but probably not causally related. Assessing lung function in addition to conventional cardiovascular risk factors to gauge risk of subclinical atherosclerosis is probably not meaningful, but low lung function found by chance should alert for atherosclerosis.

Keywords
Atherosclerosis Coronary heart disease Emphysema Spirometry
National Category
Health Sciences
Identifiers
urn:nbn:se:uu:diva-520136 (URN)10.1007/s10654-023-01088-z (DOI)
Note

Engstrom, Gunnar Lampa, Erik Dekkers, Koen Lin, Yi-Ting Ahlm, Kristin Ahlstrom, Hakan Alfredsson, Joakim Bergstrom, Goran Blomberg, Anders Brandberg, John Caidahl, Kenneth Cederlund, Kerstin Duvernoy, Olov Engvall, Jan E Eriksson, Maria J Fall, Tove Gigante, Bruna Gummesson, Anders Hagstrom, Emil Hamrefors, Viktor Hedner, Jan Janzon, Magnus Jernberg, Tomas Johnson, Linda Lind, Lars Lindberg, Eva Mannila, Maria Nilsson, Ulf Persson, Anders Persson, Hans Lennart Persson, Margaretha Ramnemark, Anna Rosengren, Annika Schmidt, Caroline Skoglund Larsson, Linn Skold, C Magnus Swahn, Eva Soderberg, Stefan Toren, Kjell Waldenstrom, Anders Wollmer, Per Zaigham, Suneela Ostgren, Carl Johan Sundstrom, Johan eng ERC-2018-STG-801965/ERC_/European Research Council/International Netherlands 2024/01/02 Eur J Epidemiol. 2024 Jan 2. doi: 10.1007/s10654-023-01088-z.

Available from: 2024-01-11 Created: 2024-01-11 Last updated: 2024-01-11
Sjöholm, T., Tarai, S., Malmberg, F., Strand, R., Korenyushkin, A., Enblad, G., . . . Kullberg, J. (2023). A whole-body diffusion MRI normal atlas: development, evaluation and initial use. Cancer Imaging, 23(1), Article ID 87.
Open this publication in new window or tab >>A whole-body diffusion MRI normal atlas: development, evaluation and initial use
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2023 (English)In: Cancer Imaging, ISSN 1740-5025, E-ISSN 1470-7330, Vol. 23, no 1, article id 87Article in journal (Refereed) Published
Abstract [en]

Background: Statistical atlases can provide population-based descriptions of healthy volunteers and/or patients and can be used for region- and voxel-based analysis. This work aims to develop whole-body diffusion atlases of healthy volunteers scanned at 1.5T and 3T. Further aims include evaluating the atlases by establishing whole-body Apparent Diffusion Coefficient (ADC) values of healthy tissues and including healthy tissue deviations in an automated tumour segmentation task.

Methods: Multi-station whole-body Diffusion Weighted Imaging (DWI) and water-fat Magnetic Resonance Imaging (MRI) of healthy volunteers (n = 45) were acquired at 1.5T (n = 38) and/or 3T (n = 29), with test-retest imaging for five subjects per scanner. Using deformable image registration, whole-body MRI data was registered and composed into normal atlases. Healthy tissue ADCmean was manually measured for ten tissues, with test-retest percentage Repeatability Coefficient (%RC), and effect of age, sex and scanner assessed. Voxel-wise whole-body analyses using the normal atlases were studied with ADC correlation analyses and an automated tumour segmentation task. For the latter, lymphoma patient MRI scans (n = 40) with and without information about healthy tissue deviations were entered into a 3D U-Net architecture.

Results: Sex- and Body Mass Index (BMI)-stratified whole-body high b-value DWI and ADC normal atlases were created at 1.5T and 3T. %RC of healthy tissue ADCmean varied depending on tissue assessed (4-48% at 1.5T, 6-70% at 3T). Scanner differences in ADCmean were visualised in Bland-Altman analyses of dually scanned subjects. Sex differences were measurable for liver, muscle and bone at 1.5T, and muscle at 3T. Volume of Interest (VOI)-based multiple linear regression, and voxel-based correlations in normal atlas space, showed that age and ADC were negatively associated for liver and bone at 1.5T, and positively associated with brain tissue at 1.5T and 3T. Adding voxel-wise information about healthy tissue deviations in an automated tumour segmentation task gave numerical improvements in the segmentation metrics Dice score, sensitivity and precision.

Conclusions: Whole-body DWI and ADC normal atlases were created at 1.5T and 3T, and applied in whole-body voxel-wise analyses.

Place, publisher, year, edition, pages
BioMed Central (BMC), 2023
National Category
Medical Image Processing
Identifiers
urn:nbn:se:uu:diva-495131 (URN)10.1186/s40644-023-00603-5 (DOI)001067462000001 ()37710346 (PubMedID)
Available from: 2023-01-24 Created: 2023-01-24 Last updated: 2023-10-06Bibliographically approved
Ahmad, N., Strand, R., Sparresäter, B., Tarai, S., Lundström, E., Bergström, G., . . . Kullberg, J. (2023). Automatic segmentation of large-scale CT image datasets for detailed body composition analysis.. BMC Bioinformatics, 24(1), Article ID 346.
Open this publication in new window or tab >>Automatic segmentation of large-scale CT image datasets for detailed body composition analysis.
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2023 (English)In: BMC Bioinformatics, E-ISSN 1471-2105, Vol. 24, no 1, article id 346Article in journal (Refereed) Published
Abstract [en]

BACKGROUND: Body composition (BC) is an important factor in determining the risk of type 2-diabetes and cardiovascular disease. Computed tomography (CT) is a useful imaging technique for studying BC, however manual segmentation of CT images is time-consuming and subjective. The purpose of this study is to develop and evaluate fully automated segmentation techniques applicable to a 3-slice CT imaging protocol, consisting of single slices at the level of the liver, abdomen, and thigh, allowing detailed analysis of numerous tissues and organs.

METHODS: The study used more than 4000 CT subjects acquired from the large-scale SCAPIS and IGT cohort to train and evaluate four convolutional neural network based architectures: ResUNET, UNET++, Ghost-UNET, and the proposed Ghost-UNET++. The segmentation techniques were developed and evaluated for automated segmentation of the liver, spleen, skeletal muscle, bone marrow, cortical bone, and various adipose tissue depots, including visceral (VAT), intraperitoneal (IPAT), retroperitoneal (RPAT), subcutaneous (SAT), deep (DSAT), and superficial SAT (SSAT), as well as intermuscular adipose tissue (IMAT). The models were trained and validated for each target using tenfold cross-validation and test sets.

RESULTS: The Dice scores on cross validation in SCAPIS were: ResUNET 0.964 (0.909-0.996), UNET++ 0.981 (0.927-0.996), Ghost-UNET 0.961 (0.904-0.991), and Ghost-UNET++ 0.968 (0.910-0.994). All four models showed relatively strong results, however UNET++ had the best performance overall. Ghost-UNET++ performed competitively compared to UNET++ and showed a more computationally efficient approach.

CONCLUSION: Fully automated segmentation techniques can be successfully applied to a 3-slice CT imaging protocol to analyze multiple tissues and organs related to BC. The overall best performance was achieved by UNET++, against which Ghost-UNET++ showed competitive results based on a more computationally efficient approach. The use of fully automated segmentation methods can reduce analysis time and provide objective results in large-scale studies of BC.

Place, publisher, year, edition, pages
BioMed Central (BMC), 2023
Keywords
Body composition, Computed tomography, Deep learning, Medical imaging, Segmentation
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:uu:diva-514086 (URN)10.1186/s12859-023-05462-2 (DOI)001068040700003 ()37723444 (PubMedID)
Available from: 2023-10-13 Created: 2023-10-13 Last updated: 2024-01-18Bibliographically approved
Veit-Haibach, P., Ahlström, H., Boellaard, R., Delgado Bolton, R. C., Hesse, S., Hope, T., . . . Herrmann, K. (2023). International EANM-SNMMI-ISMRM consensus recommendation for PET/MRI in oncology. European Journal of Nuclear Medicine and Molecular Imaging, 50(12), 3513-3537
Open this publication in new window or tab >>International EANM-SNMMI-ISMRM consensus recommendation for PET/MRI in oncology
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2023 (English)In: European Journal of Nuclear Medicine and Molecular Imaging, ISSN 1619-7070, E-ISSN 1619-7089, Vol. 50, no 12, p. 3513-3537Article in journal (Refereed) Published
Abstract [en]

The Society of Nuclear Medicine and Molecular Imaging (SNMMI) is an international scientific and professional organization founded in 1954 to promote the science, technology, and practical application of nuclear medicine. The European Association of Nuclear Medicine (EANM) is a professional non-profit medical association that facilitates communication worldwide between individuals pursuing clinical and research excellence in nuclear medicine. The EANM was founded in 1985. The merged International Society for Magnetic Resonance in Medicine (ISMRM) is an international, nonprofit, scientific association whose purpose is to promote communication, research, development, and applications in the field of magnetic resonance in medicine and biology and other related topics and to develop and provide channels and facilities for continuing education in the field.The ISMRM was founded in 1994 through the merger of the Society of Magnetic Resonance in Medicine and the Society of Magnetic Resonance Imaging. SNMMI, ISMRM, and EANM members are physicians, technologists, and scientists specializing in the research and practice of nuclear medicine and/or magnetic resonance imaging.

The SNMMI, ISMRM, and EANM will periodically define new guidelines for nuclear medicine practice to help advance the science of nuclear medicine and/or magnetic resonance imaging and to improve the quality of service to patients throughout the world. Existing practice guidelines will be reviewed for revision or renewal, as appropriate, on their fifth anniversary or sooner, if indicated. Each practice guideline, representing a policy statement by the SNMMI/EANM/ISMRM, has undergone a thorough consensus process in which it has been subjected to extensive review. The SNMMI, ISMRM, and EANM recognize that the safe and effective use of diagnostic nuclear medicine imaging and magnetic resonance imaging requires specific training, skills, and techniques, as described in each document. Reproduction or modification of the published practice guideline by those entities not providing these services is not authorized.

These guidelines are an educational tool designed to assist practitioners in providing appropriate care for patients. They are not inflexible rules or requirements of practice and are not intended, nor should they be used, to establish a legal standard of care. For these reasons and those set forth below, the SNMMI, the ISMRM, and the EANM caution against the use of these guidelines in litigation in which the clinical decisions of a practitioner are called into question.

The ultimate judgment regarding the propriety of any specific procedure or course of action must be made by the physician or medical physicist in light of all the circumstances presented. Thus, there is no implication that an approach differing from the guidelines, standing alone, is below the standard of care. To the contrary, a conscientious practitioner may responsibly adopt a course of action different from that set forth in the guidelines when, in the reasonable judgment of the practitioner, such course of action is indicated by the condition of the patient, limitations of available resources, or advances in knowledge or technology subsequent to publication of the guidelines.

The practice of medicine includes both the art and the science of the prevention, diagnosis, alleviation, and treatment of disease. The variety and complexity of human conditions make it impossible to always reach the most appropriate diagnosis or to predict with certainty a particular response to treatment.

Therefore, it should be recognized that adherence to these guidelines will not ensure an accurate diagnosis or a successful outcome. All that should be expected is that the practitioner will follow a reasonable course of action based on current knowledge, available resources, and the needs of the patient to deliver effective and safe medical care. The sole purpose of these guidelines is to assist practitioners in achieving this objective.

Place, publisher, year, edition, pages
Springer Nature, 2023
Keywords
Consensus, EANM, ISMRM, MRI, Oncology, PET, PETMR, SNMMI
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:uu:diva-514088 (URN)10.1007/s00259-023-06406-x (DOI)001059909000001 ()37624384 (PubMedID)
Available from: 2023-10-13 Created: 2023-10-13 Last updated: 2024-01-26Bibliographically approved
Jönsson, H., Ahlström, H. & Kullberg, J. (2023). Spatial mapping of tumor heterogeneity in whole-body PET-CT: a feasibility study. Biomedical engineering online, 22, Article ID 110.
Open this publication in new window or tab >>Spatial mapping of tumor heterogeneity in whole-body PET-CT: a feasibility study
2023 (English)In: Biomedical engineering online, E-ISSN 1475-925X, Vol. 22, article id 110Article in journal (Refereed) Published
Abstract [en]

Background: Tumor heterogeneity is recognized as a predictor of treatment response and patient outcome. Quantification of tumor heterogeneity across all scales may therefore provide critical insight that ultimately improves cancer management.

Methods: An image registration-based framework for the study of tumor heterogeneity in whole-body images was evaluated on a dataset of 490 FDG-PET-CT images of lung cancer, lymphoma, and melanoma patients. Voxel-, lesion- and subject-level features were extracted from the subjects' segmented lesion masks and mapped to female and male template spaces for voxel-wise analysis. Resulting lesion feature maps of the three subsets of cancer patients were studied visually and quantitatively. Lesion volumes and lesion distances in subject spaces were compared with resulting properties in template space. The strength of the association between subject and template space for these properties was evaluated with Pearson's correlation coefficient.

Results: Spatial heterogeneity in terms of lesion frequency distribution in the body, metabolic activity, and lesion volume was seen between the three subsets of cancer patients. Lesion feature maps showed anatomical locations with low versus high mean feature value among lesions sampled in space and also highlighted sites with high variation between lesions in each cancer subset. Spatial properties of the lesion masks in subject space correlated strongly with the same properties measured in template space (lesion volume, R = 0.986, p < 0.001; total metabolic volume, R = 0.988, p < 0.001; maximum within-patient lesion distance, R = 0.997, p < 0.001). Lesion volume and total metabolic volume increased on average from subject to template space (lesion volume, 3.1 +/- 52 ml; total metabolic volume, 53.9 +/- 229 ml). Pair-wise lesion distance decreased on average by 0.1 +/- 1.6 cm and maximum within-patient lesion distance increased on average by 0.5 +/- 2.1 cm from subject to template space.

Conclusions: Spatial tumor heterogeneity between subsets of interest in cancer cohorts can successfully be explored in whole-body PET-CT images within the proposed framework. Whole-body studies are, however, especially prone to suffer from regional variation in lesion frequency, and thus statistical power, due to the non-uniform distribution of lesions across a large field of view.

Place, publisher, year, edition, pages
BioMed Central (BMC), 2023
Keywords
Tumor distribution, Tumor heterogeneity, Voxel-wise analysis, Whole-body PET-CT
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:uu:diva-519106 (URN)10.1186/s12938-023-01173-0 (DOI)001123380400001 ()38007471 (PubMedID)
Funder
Swedish Cancer Society
Available from: 2024-01-04 Created: 2024-01-04 Last updated: 2024-01-04Bibliographically approved
Marchesi, S., Lundström, E., Ahlström, H. & Lipcsey, M. (2023). The Use of Diffusion Weighted Imaging and Intravoxel Incoherent Motion to Assess Edema and Perfusion in Abdominal Organs during Endotoxemia. MAGNETOCHEMISTRY, 9(2), Article ID 58.
Open this publication in new window or tab >>The Use of Diffusion Weighted Imaging and Intravoxel Incoherent Motion to Assess Edema and Perfusion in Abdominal Organs during Endotoxemia
2023 (English)In: MAGNETOCHEMISTRY, ISSN 2312-7481, Vol. 9, no 2, article id 58Article in journal (Refereed) Published
Abstract [en]

Diffusion weighted magnetic resonance imaging (DW-MRI) technique probing the microscopic movement of water molecules in tissue, allows for the quantification of water diffusivity and the contribution of perfusion to the total amount of water. In the last decades, its use in organs other than the brain has increased and it has successfully been applied to abdominal organs; otherwise the use of DWI for the assessment of perfusion (by measuring perfusion fraction and edema (by measuring the apparent diffusion coefficient-ADC) of entire organs is not a clinical standard. The aim of this paper is to assess whether DWI, specifically IVIM, can accurately assess edema (the amount of water contained in a tissue) and perfusion in abdominal organs (liver, spleen, intestine and kidneys) in an endotoxemic porcine model. Endotoxemia was induced in 20 piglets and they were divided into three groups: HM group (HighMAP, mean arterial pressure was maintained >65 mmHg by noradrenaline infusion), LM group (LowMAP, MAP was maintained between 50 and 60 mmHg) and LTD (the thoracic duct was ligated to increase abdominal edema). In addition, a fourth group of healthy controls (four animals) underwent MRI. Edema was also assessed by wet-dry weight in liver, spleen and intestine; and perfusion was assessed by hemodynamics, lactate concentration and SvO(2). ADC was found to be higher in the intestine of the LTD group compared with the other groups, in accordance with wet-dry weight. In addition, ADC in kidneys was found to be correlated to glomerular filtration rate. f was correlated with hemodynamics in kidneys and liver. The presented data show that there is a potential for clinical use of the technique in septic patients.

Place, publisher, year, edition, pages
MDPI, 2023
Keywords
diffusion-weighted imaging, apparent diffusion coefficient, f value, sepsis, endotoxemia, abdominal organs, edema, perfusion
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:uu:diva-499157 (URN)10.3390/magnetochemistry9020058 (DOI)000940839700001 ()
Available from: 2023-04-03 Created: 2023-04-03 Last updated: 2023-04-03Bibliographically approved
Thunswärd, P., Österberg, K. & Ahlström, H. (2023). Ultrasound Contrast Agent Priming of Biopsy and Introducer Needles by Using a Small Syringe to Improve Needle Visibility in a Phantom Model. Cardiovascular and Interventional Radiology, 46(8), 1066-1075
Open this publication in new window or tab >>Ultrasound Contrast Agent Priming of Biopsy and Introducer Needles by Using a Small Syringe to Improve Needle Visibility in a Phantom Model
2023 (English)In: Cardiovascular and Interventional Radiology, ISSN 0174-1551, E-ISSN 1432-086X, Vol. 46, no 8, p. 1066-1075Article in journal (Refereed) Published
Abstract [en]

Purpose

Biopsy under the guidance of contrast-enhanced ultrasound is sometimes useful. Needle visualization in contrast-specific imaging-mode is often poor; however, it may be improved by priming the needles with an ultrasound contrast agent. This study aimed to evaluate needle priming methods using the ultrasound contrast agent sulfur hexafluoride and a 1 mL syringe.

Material and Methods

Two kinds of biopsy needles, side-notch and full core, and one kind of introducer needle were primed using non-primed needles as controls (n = 180). Recordings of punctures were performed in a water bath phantom to which the ultrasound contrast agent had also been added. Contrast-specific imaging-mode needle visibility was evaluated for the entire needles and the needle tips, respectively, quantitatively by calculating the contrast-to-noise ratio and qualitatively via grading by three radiologists.

Results

The contrast-to-noise ratio following the ultrasound contrast agent priming was superior compared to the controls for the entire needles of all three types (p < 0.001) and for the needle tips of the core biopsy needles and introducer needles (p < 0.001). However, the ratio was equal to the controls for the needle tips of the side-notch biopsy needles (p = 0.19). Needle visibility following the ultrasound contrast agent priming was qualitatively superior compared to the controls for both the entire needles and the needle tips, and the difference was considered clinically relevant by the assessors (p < 0.001).

Conclusion

The ultrasound contrast agent needle priming methods described increased the contrast-specific imaging-mode needle visibility in a phantom model. Nonetheless, the results also need to be confirmed in vivo.

Place, publisher, year, edition, pages
Springer Nature, 2023
Keywords
Needle visibility, Ultrasound, Contrast-enhanced ultrasound, Contrast-specific imaging-mode, Needle priming, Ultrasound contrast agent, Needle filling, Core needle biopsy, Core biopsy needle, Introducer needle
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:uu:diva-510939 (URN)10.1007/s00270-023-03500-3 (DOI)001028420300003 ()37438650 (PubMedID)
Funder
Swedish Cancer Society, 2020 1303 PjF01Region UppsalaUppsala University
Available from: 2023-09-13 Created: 2023-09-13 Last updated: 2023-09-13Bibliographically approved
Jönsson, H., Ekström, S., Strand, R., Pedersen, M. A., Molin, D., Ahlström, H. & Kullberg, J. (2022). An image registration method for voxel-wise analysis of whole-body oncological PET-CT. Scientific Reports, 12, Article ID 18768.
Open this publication in new window or tab >>An image registration method for voxel-wise analysis of whole-body oncological PET-CT
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2022 (English)In: Scientific Reports, E-ISSN 2045-2322, Vol. 12, article id 18768Article in journal (Refereed) Published
Abstract [en]

Whole-body positron emission tomography-computed tomography (PET-CT) imaging in oncology provides comprehensive information of each patient's disease status. However, image interpretation of volumetric data is a complex and time-consuming task. In this work, an image registration method targeted towards computer-aided voxel-wise analysis of whole-body PET-CT data was developed. The method used both CT images and tissue segmentation masks in parallel to spatially align images step-by-step. To evaluate its performance, a set of baseline PET-CT images of 131 classical Hodgkin lymphoma (cHL) patients and longitudinal image series of 135 head and neck cancer (HNC) patients were registered between and within subjects according to the proposed method. Results showed that major organs and anatomical structures generally were registered correctly. Whole-body inverse consistency vector and intensity magnitude errors were on average less than 5 mm and 45 Hounsfield units respectively in both registration tasks. Image registration was feasible in time and the nearly automatic pipeline enabled efficient image processing. Metabolic tumor volumes of the cHL patients and registration-derived therapy-related tissue volume change of the HNC patients mapped to template spaces confirmed proof-of-concept. In conclusion, the method established a robust point-correspondence and enabled quantitative visualization of group-wise image features on voxel level.

Place, publisher, year, edition, pages
Springer Nature, 2022
National Category
Radiology, Nuclear Medicine and Medical Imaging
Research subject
Computerized Image Processing; Computerized Image Processing
Identifiers
urn:nbn:se:uu:diva-488091 (URN)10.1038/s41598-022-23361-z (DOI)000879722100009 ()36335130 (PubMedID)
Funder
Swedish Cancer Society, 20 1303 PjF 01 H
Available from: 2022-11-09 Created: 2022-11-09 Last updated: 2022-12-05Bibliographically approved
Julian, V., Bergsten, P., Ennequin, G., Forslund, A., Ahlström, H., Ciba, I., . . . Weghuber, D. (2022). Association between alanine aminotransferase as surrogate of fatty liver disease and physical activity and sedentary time in adolescents with obesity. European Journal of Pediatrics, 181(8), 3119-3129
Open this publication in new window or tab >>Association between alanine aminotransferase as surrogate of fatty liver disease and physical activity and sedentary time in adolescents with obesity
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2022 (English)In: European Journal of Pediatrics, ISSN 0340-6199, E-ISSN 1432-1076, Vol. 181, no 8, p. 3119-3129Article in journal (Refereed) Published
Abstract [en]

To compare patterns of sedentary (SED) time (more sedentary, SED + vs less sedentary, SED-), moderate to vigorous physical activity (MVPA) time (more active, MVPA + vs less active, MVPA-), and combinations of behaviors (SED-/MVPA + , SED-/MVPA-, SED + /MVPA + , SED + /MVPA-) regarding nonalcoholic fatty liver diseases (NAFLD) markers. This cross-sectional study included 134 subjects (13.4 +/- 2.2 years, body mass index (BMI) 98.9 +/- 0.7 percentile, 48.5% females) who underwent 24-h/7-day accelerometry, anthropometric, and biochemical markers (alanine aminotransferase (ALT) as first criterion, and aspartate aminotransferase (AST), gamma-glutamyl transpeptidase (GGT), AST/ALT ratio as secondary criteria). A subgroup of 39 patients underwent magnetic resonance imaging-liver fat content (MRI-LFC). Hepatic health was better in SED- (lower ALT, GGT, and MRI-LFC (p < 0.05), higher AST/ALT (p < 0.01)) vs SED + and in MVPA + (lower ALT (p < 0.05), higher AST/ALT (p < 0.01)) vs MVPA- groups after adjustment for age, gender, and Tanner stages. SED-/MVPA + group had the best hepatic health. SED-/MVPA- group had lower ALT and GGT and higher AST/ALT (p < 0.05) in comparison with SED + /MVPA + group independently of BMI. SED time was positively associated with biochemical (high ALT, low AST/ALT ratio) and imaging (high MRI-LFC) markers independently of MVPA. MVPA time was associated with biochemical markers (low ALT, high AST/ALT) but these associations were no longer significant after adjustment for SED time. Conclusion: Lower SED time is associated with better hepatic health independently of MVPA. Reducing SED time might be a first step in the management of pediatric obesity NAFLD when increasing MVPA is not possible.

Place, publisher, year, edition, pages
Springer, 2022
Keywords
Sedentary behavior, Physical activity, Pediatric obesity, Nonalcoholic fatty liver disease
National Category
Pediatrics
Identifiers
urn:nbn:se:uu:diva-484603 (URN)10.1007/s00431-022-04539-z (DOI)000819274200002 ()35771354 (PubMedID)
Funder
Swedish Research Council, 2016-01040
Available from: 2022-09-30 Created: 2022-09-30 Last updated: 2022-09-30Bibliographically approved
Projects
Leverfett som ny måltavla för kostbehandling av kardiometabola rubbningar vid prediabetes och diabetes [20180709_HLF]; Uppsala University
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-8701-969x

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