| 1. |
- Edholm, David, et al.
(författare)
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Preoperative 4-week low-calorie diet reduces liver volume and intrahepatic fat, and facilitates laparoscopic gastric bypass in morbidly obese
- 2011
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Ingår i: Obesity Surgery. - : Springer Science and Business Media LLC. - 0960-8923 .- 1708-0428. ; 21:3, s. 345-350
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The aim of this study was to explore changes in liver volume and intrahepatic fat in morbidly obese patients during 4 weeks of low-calorie diet (LCD) before surgery and to investigate if these changes would facilitate the following laparoscopic gastric bypass.METHODS: Fifteen female patients (121.3 kg, BMI 42.9) were treated preoperatively in an open study with LCD (800-1,100 kcal/day) during 4 weeks. Liver volume and fat content were assessed by magnetic resonance imaging and spectroscopy before and after the LCD treatment.RESULTS: Liver appearance and the complexity of the surgery were scored at the operation. Eighteen control patients (114.4 kg, BMI 40.8), without LCD were scored similarly. Average weight loss in the LCD group was 7.5 kg, giving a mean weight of 113.9 kg at surgery. Liver volume decreased by 12% (p < 0.001) and intrahepatic fat by 40% (p < 0.001). According to the preoperative scoring, the size of the left liver lobe, sharpness of the liver edge, and exposure of the hiatal region were improved in the LCD group compared to the controls (all p < 0.05).CONCLUSIONS: The overall complexity of the surgery was perceived lower in the LCD group (p < 0.05), due to improved exposure and reduced psychological stress (both p < 0.05). Four weeks of preoperative LCD resulted in a significant decrease in liver volume and intrahepatic fat content, and facilitated the subsequent laparoscopic gastric bypass as scored by the surgeon
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| 2. |
- Eriksson, Rolf, 1979-
(författare)
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The Utility of Manganese for Magnetic Resonance Imaging of Transient Myocardial Ischemia
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In order to improve the diagnosis of coronary artery disease, better methods for detection of myocardial perfusion defects would be useful. One of the methods used for myocardial perfusion evaluation today is magnetic resonance imaging. This method could be improved if a contrast agent that induced long-lasting contrast enhancement in the myocardium could be developed. The paramagnetic manganese(II) ion has promising properties for meeting this need, since it enters cardiomyocytes through voltage-gated calcium channels and remains inside the cells for a long time after an intravenous injection. If these properties can be utilized, manganese-enhanced MRI has potential for detecting transient periods of ischemia in a manner similar to the conventional SPECT stress test.To investigate the contrast-enhancing properties of the manganese(II) ion, a series of experiments was performed in pigs, using a manganese salt (MnCl2) and two manganese-based chelates (MnDPDP and MnHPTA) and measuring the longitudinal relaxation rates before and after contrast agent administration. This was done in normal pig myocardium at rest and during dobutamine-induced stress with several different doses of contrast agent, and in a model for coronary artery stenosis using MnCl2 administered during dobutamine stress to determine whether transient ischemia could be detected with this contrast agent.The results of these experiments showed that of the three contrast agents, MnCl2 induces the greatest increase in ΔR1, followed by MnHPTA. Using MnCl2 it was possible to produce images on which transient myocardial ischemia was visible, but only during the first 30 minutes after contrast agent injection.The stenosis model is still far from the clinical situation and several complications, including the potential toxicity of the manganese(II) ion, remain to be overcome. However, the results from this model are promising for the future development of manganese- enhanced magnetic resonance imaging of transient myocardial ischemia.
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| 3. |
- Glimelius, Bengt, et al.
(författare)
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U-CAN : a prospective longitudinal collection of biomaterials and clinical information from adult cancer patients in Sweden.
- 2018
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Ingår i: Acta Oncologica. - : Taylor & Francis. - 0284-186X .- 1651-226X. ; 57:2, s. 187-194
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Tidskriftsartikel (refereegranskat)abstract
- Background: Progress in cancer biomarker discovery is dependent on access to high-quality biological materials and high-resolution clinical data from the same cases. To overcome current limitations, a systematic prospective longitudinal sampling of multidisciplinary clinical data, blood and tissue from cancer patients was therefore initiated in 2010 by Uppsala and Umeå Universities and involving their corresponding University Hospitals, which are referral centers for one third of the Swedish population.Material and Methods: Patients with cancer of selected types who are treated at one of the participating hospitals are eligible for inclusion. The healthcare-integrated sampling scheme encompasses clinical data, questionnaires, blood, fresh frozen and formalin-fixed paraffin-embedded tissue specimens, diagnostic slides and radiology bioimaging data.Results: In this ongoing effort, 12,265 patients with brain tumors, breast cancers, colorectal cancers, gynecological cancers, hematological malignancies, lung cancers, neuroendocrine tumors or prostate cancers have been included until the end of 2016. From the 6914 patients included during the first five years, 98% were sampled for blood at diagnosis, 83% had paraffin-embedded and 58% had fresh frozen tissues collected. For Uppsala County, 55% of all cancer patients were included in the cohort.Conclusions: Close collaboration between participating hospitals and universities enabled prospective, longitudinal biobanking of blood and tissues and collection of multidisciplinary clinical data from cancer patients in the U-CAN cohort. Here, we summarize the first five years of operations, present U-CAN as a highly valuable cohort that will contribute to enhanced cancer research and describe the procedures to access samples and data.
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| 4. |
- Hagström, Emil, et al.
(författare)
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Plasma-parathyroid hormone is associated with subclinical and clinical atherosclerotic disease in 2 community-based cohorts
- 2014
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Ingår i: Arteriosclerosis, Thrombosis and Vascular Biology. - 1079-5642 .- 1524-4636. ; 34:7, s. 1567-1579
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Cardiovascular risk factors have different impact on different arterial territories. Diseases with elevated circulating parathyroid hormone (PTH) such as primary hyperparathyroidism and chronic renal failure have been shown to be associated with an increased risk of cardiovascular disease, predominantly heart or cerebrovascular diseases. However, data on the associations between circulating PTH and peripheral atherosclerosis are limited.APPROACH AND RESULTS: Two prospective, community-based studies were used. In 306 men and women, who were 70 years old, from the Prospective investigation of the vasculature in Uppsala seniors (PIVUS) study, cross-sectional relations between PTH and atherosclerotic burden assessed by whole-body magnetic resonance angiography were investigated. In 998 men, who were 71 years old, from the Uppsala longitudinal study of adult men (ULSAM) study, the association between PTH concentration and risk of subsequent nonfatal atherosclerotic disease (excluding coronary or cerebrovascular disease) was investigated. Adjusting for established vascular risk factors, PTH was associated with burden of atherosclerosis (increase in total atherosclerotic score per SD PTH increase: 0.04, 0.003-0.08; P=0.03) in the PIVUS study. During follow-up in the ULSAM study (median 16.7 years), 89 men were diagnosed with nonfatal atherosclerotic disease. In Cox-regression analyses adjusting for established vascular risk factors and mineral metabolism, higher PTH was associated with an increased risk of nonfatal atherosclerotic disease (hazard ratio for 1 SD increase of PTH: 1.55, 1.33-1.88; P<0.0001). Results were similar when including fatal atherosclerotic disease in the outcome.CONCLUSIONS: In 2 independent community-based cohorts, PTH was associated to the degree of atherosclerosis and risk of clinically overt atherosclerotic disease, respectively. Our data confirm and extend previous studies supporting a role for PTH in the development of atherosclerotic disease.
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| 5. |
- Hagström, Emil, et al.
(författare)
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Plasma parathyroid hormone is associated with vascular dementia and cerebral hyperintensities in two community-based cohorts
- 2014
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 99:11, s. 4181-4189
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Tidskriftsartikel (refereegranskat)abstract
- Context: In diseases with increased PTH such as hyperparathyroidism and chronic renal failure, dementia is common. Little is known of PTH and dementia in the community.Objective: We sought to investigate relations between PTH, clinical dementia and cerebral micro-vascular disease. Setting and Design: The Uppsala Longitudinal Study Of Adult Men (ULSAM) was prospective, baseline, 1991-1995; followup, 15.8 years. The Prospective Investigation Of The Vasculature In Uppsala Seniors (PIVUS) was cross-sectional, baseline, 2001. Both settings were community based.Participants and Main Outcome Measure: In the ULSAM study of 998 men (age 71) the association between PTH and dementia was investigated. In the PIVUS study of 406 men and women (age 70) the relation between PTH and magnetic resonance imaging signs of cerebral small vascular disease was investigated.Results: During followup, 56 individuals were diagnosed with vascular, 91 with Alzheimer's, and 59 with other dementias. In Cox-regression analyses, higher PTH was associated with vascular dementia (hazard ratio per 1 SD increase of PTH, 1.41; P < .01), but not with other dementias. The top tertile of PTH accounted for 18.5% of the population-attributable risk for vascular dementia, exceeding all other risk factors. In linear regression analysis in PIVUS, PTH was associated with increasing white matter hyperintensities (WMHI), reflecting increasing burden of cerebral small vessel disease (1 SD PTH increase, 0.31 higher category of WMHI; P = .016). All models were adjusted for vascular risk factors and mineral metabolism.Conclusions: In two community-based samples, PTH predicted clinically diagnosed and neuroimaging indices of vascular dementia and cerebral small vessel disease. Our data suggest a role for PTH in the development of vascular dementia.
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| 6. |
- Hedström, Erik, et al.
(författare)
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Importance of perfusion in myocardial viability studies using delayed contrast-enhanced magnetic resonance imaging
- 2006
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Ingår i: Journal of Magnetic Resonance Imaging. - : Wiley. - 1053-1807 .- 1522-2586. ; 24:1, s. 77-83
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To investigate whether an extracellular gadolinium-(Gd)-based contrast agent (CA) enters nonperfused myocardium during acute coronary occlusion, and whether nonperfused myocardium presents as hyperintense in delayed contrast-enhanced (DE) MR images in the absence of CA in that region. MATERIALS AND METHODS: The left anterior descending coronary artery (LAD) was occluded for 200 minutes in six pigs. The longitudinal relaxation rate (R(1)) in blood, perfused myocardium, and nonperfused myocardium was repeatedly measured using a Look-Locker sequence before and during the first hour after administration of Gd-DTPA-BMA. RESULTS: While blood and perfused myocardium showed a major increase in R(1) after CA administration, nonperfused myocardium did not. R(1) in nonperfused myocardium was significantly lower than in blood and perfused myocardium during the first hour after CA administration. When the signal from perfused myocardium was nulled, demarcation of the hyperintense nonperfused myocardium was achieved in all of the study animals. CONCLUSION: Gd-DTPA-BMA does not enter ischemic myocardium within one hour after administration during acute coronary occlusion. The ischemic region with complete absence of CA still appears bright when the signal from perfused myocardium is nulled using inversion-recovery DE-MRI. This finding is important for understanding the basic pathophysiology of inversion-recovery viability imaging, as well as for imaging of acute coronary syndromes.
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| 7. |
- Kullberg, Joel, et al.
(författare)
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Gastric bypass promotes more lipid mobilization than a similar weight loss induced by low-calorie diet
- 2011
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Ingår i: Journal of Obesity. - : Hindawi Limited. - 2090-0708 .- 2090-0716. ; 2011, s. 959601-
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Tidskriftsartikel (refereegranskat)abstract
- Background.Recently, we found large reductions in visceral and subcutaneous fat one month after gastric bypass (GBP), without any change in liver fat content.Purpose.Firstly to characterize weight loss-induced lipid mobilization after one month with preoperative low-calorie diet (LCD) and a subsequent month following GBP, and secondly, to discuss the observations with reference to our previous published findings after GBP intervention alone.Methods.15 morbidly obese women were studied prior to LCD, at GBP, and one month after GBP. Effects on metabolism were measured by magnetic resonance techniques and blood tests.Results.Body weight was similarly reduced after both months (mean: -8.0 kg, n = 13). Relative body fat changes were smaller after LCD than after GBP (-7.1 ± 3.6% versus -10 ± 3.2%, P = .029, n = 13). Liver fat fell during the LCD month (-41%, P = .001, n = 13) but was unaltered one month after GBP (+12%).Conclusion.Gastric bypass seems to cause a greater lipid mobilization than a comparable LCD-induced weight loss. One may speculate that GBP-altered gastrointestinal signalling sensitizes adipose tissue to lipolysis, promoting the changes observed.
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| 8. |
- Melhus, Håkan, et al.
(författare)
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Use of novel bone biopsy system to study molecular effects of growth hormone in human bone : a pilot study
- 1999
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Ingår i: IUBMB Life - A Journal of the International Union of Biochemistry and Molecular Biology. - : Wiley. - 1521-6543 .- 1521-6551. ; 48:2, s. 175-178
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we have examined whether a novel bone biopsy system combined with reverse transcription-polymerase chain reaction (RT-PCR) or differential display PCR (ddPCR) can be used to detect specific mRNAs induced by growth hormone (GH) in human bone. In a 58-year-old man with complete GH deficiency as a result of empty sella, bone biopsies were taken before, and 5 and 24 h after administration of 24 recombinant human GH. Insulin-like growth factor binding protein-3 (IGFBP-3) mRNA levels in this patient, measured in a semiquantitative RT-PCR assay, increased about 40% 24 h after GH administration. This increase was not seen in a healthy control who did not receive GH, suggesting that the increase was an effect of GH rather than of the biopsy itself. Several differentially expressed mRNAs were detected by ddPCR. Thus, this pilot study suggests that our novel bone biopsy system may be suitable for in vivo studies of the molecular effects of substances with essential functions in human bone.
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| 9. |
- Weis, Jan, et al.
(författare)
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MR spectroscopy of the human prostate using surface coil at 3 T : Metabolite ratios, age-dependent effects, and diagnostic possibilities
- 2011
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Ingår i: Journal of Magnetic Resonance Imaging. - : Wiley. - 1053-1807 .- 1522-2586. ; 34:6, s. 1277-1284
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To measure prostate spectra of healthy volunteers using a surface coil, to demonstrate age-dependent effects, and to investigate diagnostic possibilities for prostate cancer detection. MATERIALS AND METHODS: Single-voxel and 2D magnetic resonance spectroscopic imaging (MRSI) spectra of 51 healthy volunteers with biopsy-proven prostate carcinoma of 20 patients for comparison were measured and processed using the LCModel. The mean normalized spectra and mean metabolite-to-citrate intensity ratios were computed. RESULTS: Metabolite-to-citrate ratios of healthy volunteers were lower in the older group (>51 years) than in the younger group (<45 years). The peripheral zone (PZ) revealed a lower metabolite-to-citrate intensity ratio than the central gland (CG). Age-related differences in metabolite-to-citrate ratio were insignificant in the voxels with predominantly CG tissue, whereas significant differences were found in the PZ. Sensitivity in detecting prostate cancer by single-voxel spectroscopy (SVS) and 2D MRSI was 75% and 80%, respectively. CONCLUSION: SVS and 2D MRSI of the prostate at 3 T, using a surface coil, are useful in situations when insertion of the endorectal coil into the rectum is difficult or impossible. Our findings of age-dependent effects may be of importance for the analysis of patient spectra.
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| 10. |
- Örlefors, Håkan, et al.
(författare)
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Positron emission tomography with 5-hydroxytryprophan in neuroendocrine tumors
- 1998
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Ingår i: Journal of Clinical Oncology. - 0732-183X .- 1527-7755. ; 16:7, s. 2534-2541
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Carcinoid tumors, especially those of midgut origin, produce serotonin via the precursors tryptophan and 5-hydroxytryptophan (5-HTP). We have evaluated the usefulness of positron emission tomography (PET) with carbon-11-labeled 5-HTP in the diagnosis and treatment follow-up evaluation of patients with neuroendocrine tumors. PATIENTS AND METHODS: PET using 11C-labeled 5-HTP was compared with computed tomography (CT) in 18 patients (14 midgut, one foregut, one hindgut carcinoid, and two endocrine pancreatic tumors [EPT]). In addition, 10 of 18 patients were monitored with PET examinations during treatment. RESULTS: All 18 patients, including two with normal urinary 5-hydroxyindole acetic acid (U-5-HIAA), had increased uptake of 11C-labeled 5-HTP in tumorous tissue as compared with normal tissue. Liver metastases, as well as lymph node, pleural, and skeletal metastases, showed enhanced 5-HTP uptake and PET could detect more lesions than CT in 10 patients and equal numbers in the others. Tumor visibility was better for PET than for CT due to the high and selective uptake of 5-HTP with a high tumor-to-background ratio. Binding studies indicated an irreversible trapping of 5-HTP in the tumors. Linear regression analyses showed a clear correlation (r = .907) between changes in U-5-HIAA and changes in the transport rate constant for 5-HTP during treatment. CONCLUSION: PET with 11C-labeled 5-HTP demonstrated high uptake in neuroendocrine gastrointestinal tumors and thereby allowed improved visualization compared with CT. The in vivo data on regional tumor metabolism, as expressed in 11C-5-HTP uptake and transport rate, provided additional information over conventional radiologic techniques. The close correlation between the changes in 11C-5-HTP transport rate and U-HIAA during medical treatment indicates the potential of 11C-5-HTP-PET as a means to monitor therapy.
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| 11. |
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| 12. |
- Abdul Qadhr, Göran, et al.
(författare)
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Whole-body diffusion-weighted imaging compared with FDG-PET/CT in staging of lymphoma patients
- 2011
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Ingår i: Acta Radiologica. - : SAGE Publications. - 0284-1851 .- 1600-0455. ; 52:2, s. 173-180
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Tidskriftsartikel (refereegranskat)abstract
- Background:Diffusion-weighted imaging (DWI) has become increasingly valuable in lymph node imaging, yet the clinical utility of this technique in the staging of lymphoma has not been established.Purpose:To compare whole-body DWI with FDG-PET/CT in the staging of lymphoma patients.Material and Methods:Thirty-one patients, eight with Hodgkin lymphoma (HL) and 23 with non-Hodgkin's lymphoma (18 aggressive and five indolent) underwent both whole-body DWI, whole-body MRI (T1W and T2W-STIR) and FDG-PET/CT. Lesions on whole-body DWI were only considered positive if they correlated with lesions on T1W and T2W-STIR images. The staging given by each technique was compared, according to the Ann Arbor staging system. Differences in staging were solved using biopsy results, and clinical and CT follow-ups as standard of reference.Results: The staging was the same for DWI and FDG-PET/CT in 28 (90.3%) patients and different in three (9.7%). Of the 28 patients with the same staging, 11 had stage IV in both techniques and 17 had stages 0-III. No HL or aggressive non-Hodgkin's lymphoma patients had different staging. Three indolent small lymphocytic lymphoma/chronic lymphocytic leukemia (SLL/CLL) lymphoma had higher staging with DWI when compared with FDG-PET/CT. One small subcutaneous breast lymphoma was not seen but all other extranodal sites were detected by both techniques.Conclusion:Whole-body DWI is a promising technique for staging of both (aggressive and indolent) non-Hodgkin's lymphoma and HL.
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| 13. |
- Abdulla, Maysaa, et al.
(författare)
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Prognostic impact of abdominal lymph node involvement in diffuse large B-cell lymphoma
- 2020
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Ingår i: European Journal of Haematology. - : Wiley. - 0902-4441 .- 1600-0609. ; 104:3, s. 207-213
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The prognostic value of site of nodal involvement in diffuse large B-cell lymphomas (DLBCL) is mainly unknown. We aimed to determine the prognostic significance of nodal abdominal involvement in relation to tumour cell markers and clinical characteristics of 249 DLBCL patients in a retrospective single-centre study.METHODS: Contrast-enhanced computed tomography (CT) of the abdomen and thorax revealed pathologically enlarged abdominal lymph nodes in 156 patients, while in 93 patients there were no pathologically enlarged lymph nodes in the abdomen. In 81 cases, the diagnosis of DLBCL was verified by histopathological biopsy obtained from abdominal lymph node.RESULTS: Patients with abdominal nodal disease had inferior lymphoma-specific survival (P = .04) and presented with higher age-adjusted IPI (P < .001), lactate dehydrogenase (P < .001) and more often advanced stage (P < .001), bulky disease (P < .001), B symptoms (P < .001), and double expression of MYC and BCL2 (P = .02) compared to patients without nodal abdominal involvement, but less often extranodal involvement (P < .02). The worst outcome was observed in those where the abdominal nodal involvement was verified by histopathological biopsy.CONCLUSION: Diffuse large B-cell lymphomas patients with abdominal nodal disease had inferior outcome and more aggressive behaviour, reflected both in clinical and biological characteristics.
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| 14. |
- Ahlström, Håkan, et al.
(författare)
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An experimental model for pharmacokinetic studies of monoclonal antibodies in human colonic cancer
- 1987
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Ingår i: Acta Oncologica. - 0284-186X .- 1651-226X. ; 26:6, s. 447-451
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Tidskriftsartikel (refereegranskat)abstract
- An experimental model consisting of athymic rats carrying human colonic tumours from cell line LS 174T in both hind legs was used. 125I-labelled anti-carcinoembryonic antigen (anti-CEA) monoclonal antibodies were injected intra-arterially (i.a.), either alone (21 rats) or together with degradable starch microspheres (6 rats). As a control, an irrelevant antibody was injected i.a., alone (6 rats) or together with microspheres (3 rats). An intra-arterial injection was given on the side bearing one tumour in each rat, while the contralateral tumour served as an 'intravenous' control. The rats were submitted to external gamma measurements daily for four days. On the fourth day they were killed and pieces from the tumours and from various organs were examined by in vitro measurements. The results indicate strong expression of CEA in LS 174T cells grafted to athymic rats. No lasting enhancement of the tumour uptake was achieved by intra-arterial injection of antibodies as compared with the control tumours.
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| 15. |
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| 16. |
- Ahlström, Håkan, et al.
(författare)
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CT-guided bone biopsy performed by means of a coaxial biopsy system with an eccentric drill
- 1993
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Ingår i: Radiology. - 0033-8419 .- 1527-1315. ; 188:2, s. 549-552
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Tidskriftsartikel (refereegranskat)abstract
- Thirty-seven consecutive bone biopsies guided with computed tomography were performed in 32 patients by use of three different techniques to penetrate cortical bone and gain access to the lesion. The following instruments were used: a thin bone biopsy needle (12 biopsies), a conventional drill with an outer cannula (six biopsies), and a coaxial biopsy system that consists of a drill with an eccentric tip and an outer cannula (19 biopsies). This eccentric drill makes a hole in the bone larger than the diameter of the cannula and thereby makes it easy to advance the cannula over the drill until the cannula is anchored in the bone. One can then obtain multiple samples through the cannula. The thin bone biopsy needle could not penetrate thick (8 mm thick) cortical bone. The outer cannula was not anchored in the bone when the conventional drill was used. In 16 biopsies, the new coaxial biopsy system penetrated cortical bone with a thickness of 1-8 mm and was anchored there, and lesion samples were obtained through the anchored cannula.
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| 17. |
- Ahlström, Håkan, et al.
(författare)
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Enhanced uptake of intra-arterially injected anti-CEA monoclonal antibodies in human colonic cancer after mannitol infusion in an experimental model
- 1987
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Ingår i: Acta Oncologica. - 0284-186X .- 1651-226X. ; 26:6, s. 453-458
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Tidskriftsartikel (refereegranskat)abstract
- In a previous report athymic rats carrying transplanted human colonic tumours from cell line LS 174T in both hind legs were injected intra-arterially (i.a.) with 125I-labelled anti-carcinoembryonic (anti-CEA) monoclonal antibodies. The i.a. injection was given on one side bearing a tumour in each rat, while the contralateral tumour served as an 'intravenous' control. In the same experimental model and treated in the same way, 10 rats were injected i.a. with anti-CEA monoclonal antibodies after an i.a. mannitol infusion. In both groups of rats external gamma measurements were performed daily for four days. On the fourth day the rats were killed and pieces of the tumours and of various organs were weighed and the activity was determined with a gamma-counter. The tumour uptake of antibodies was significantly enhanced after mannitol infusion.
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| 18. |
- Ahlström, Håkan, et al.
(författare)
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Inoperable biliary obstruction treated with percutaneously placed endoprosthesis
- 1986
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Ingår i: Acta chirurgica Scandinavica. - 0001-5482. ; 152, s. 301-303
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Tidskriftsartikel (refereegranskat)abstract
- Biliary obstruction was treated with endoprosthetic drainage in 30 patients with pancreatic, 10 with gallbladder and 27 with biliary duct cancer, and 13 of the patients received more than one endoprosthesis. The median survival time in the respective cancer groups was 12, 10 and 9 weeks, including 6, 3 and 4 weeks spent in the patients' own homes. The patients with multiple endoprostheses had 24 weeks median survival with 22 weeks at home. Another patient, with a medically treated malignant endocrine tumour of the pancreas, lived for more than 3 years after biliary tract stenting. Complications associated with insertion of endoprosthesis were few, and clinical cholangitis occurred in seven cases. For individual patients it is difficult to predict the benefit of endoprosthetic drainage, but the procedure seems questionable if the predrainage bilirubin level is very high.
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| 19. |
- Ahlström, Håkan, et al.
(författare)
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Magnetic resonance imaging of sacroiliac joint inflammation
- 1990
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Ingår i: Arthritis and Rheumatism. - 0004-3591 .- 1529-0131. ; 33:12, s. 1763-1769
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Tidskriftsartikel (refereegranskat)abstract
- A consecutive series of 27 patients with symptoms compatible with sacroiliitis underwent magnetic resonance imaging (MRI) of the sacroiliac joints. The diagnostic sensitivity of MRI was similar to that of computed tomography or conventional radiography. However, MRI seems to have the potential of providing unique information about the disease process in sacroiliitis by demonstrating abnormalities in subchondral bone and periarticular bone marrow. The results of this study suggest that early inflammatory changes in sacroiliitis occur in the subchondral structures of the sacroiliac joints.
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| 20. |
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| 21. |
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| 22. |
- Ahlström, Håkan, et al.
(författare)
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Overview of MnDPDP as a pancreas-specific contrast agent for MR imaging
- 1997
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Ingår i: Acta Radiologica. - 0284-1851 .- 1600-0455. ; 38:4 Pt 2, s. 660-664
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To describe and discuss previous and ongoing clinical and experimental studies with MnDPDP (Teslascan) as a pancreas-specific contrast agent for MR imaging. MATERIAL AND METHODS: All results, both experimental and clinical, applying MnDPDP as a pancreas-specific contrast agent for MR imaging, were collected. RESULTS: An increase of up to 100% in signal intensity was seen in normal pancreatic parenchyma, reaching its maximum approximately 25 min after the beginning of MnDPDP administration. Maximal enhancement was sustained for 4 h. Enhancement was only seen in the T1-weighted images. No enhancement was observed in tumours and an increase in contrast-to-noise of about 200% was obtained. The uptake of MnDPDP in pancreatitis compared with normal pancreatic parenchyma was decreased in an animal model. CONCLUSION: Improved depiction and demarcation of pancreatic tumours with MR imaging were obtained after administration of MnDPDP. MR imaging with and without MnDPDP might be valuable for staging of pancreatitis.
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| 23. |
- Ahlström, Håkan, et al.
(författare)
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Pancreatic neuroendocrine tumors : diagnosis with PET
- 1995
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Ingår i: Radiology. - 0033-8419 .- 1527-1315. ; 195:2, s. 333-337
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To evaluate the use of carbon-11-labeled L-dihydroxyphenylalanine (L-DOPA) and hydroxytryptophan (5-HTP) in the diagnosis of pancreatic endocrine tumors with positron emission tomography (PET). MATERIALS AND METHODS: Twenty-two consecutive patients with clinically and biochemically verified pancreatic endocrine tumors were examined with computed tomography (CT) and PET with L-DOPA alone (n = 16) or both C-11-L-DOPA and C-11-5-HTP (n = 6). RESULTS: Tumor uptake of L-DOPA was found in 11 patients, eight of whom had metastatic disease. Heterogeneity of tracer uptake was noted among different lesions in the same patient (ie, high uptake in some lesions and low uptake in others). Results in patients examined with both L-DOPA and 5-HTP correlated well, but the uptake levels of 5-HTP were higher in two of three patients with positive findings. In two additional patients, CT enabled detection of tumors not detected at PET. CONCLUSION: The current PET technique can be a valuable complement to CT in demonstration of functional pancreatic endocrine tumors, in particular, glucagonomas, but is less useful in detection of nonfunctional tumors.
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| 24. |
- Ahlström, Håkan, et al.
(författare)
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Positron emission tomography in the diagnosis and staging of urinary bladder cancer
- 1996
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Ingår i: Acta Radiologica. - 0284-1851 .- 1600-0455. ; 37:2, s. 180-185
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Evaluation of positron emission tomography (PET) using (18)fl 18F-2-fluoro-2-deoxy-D-glucose (18FDG) and L-methyl-11C-methionine in the diagnosis and staging of urinary bladder carcinoma. MATERIAL AND METHODS: Twenty-three patients with biopsy-proven urinary bladder carcinoma were examined with PET after intravenous injection of 11C-methionine; 2 were also examined with 18FDG. The results from the PET investigations were compared with CT or MR findings and TNM classification before and after treatment. RESULTS: The urinary excretion of 18FDG prevented distinction of the primary tumour from the surrounding tracer. With 11C-methionine it was possible to detect 18/23 primary tumours. A trend was seen, suggesting that the higher the uptake values of 11C-methionine in the tumour, the greater the tumour stage. CONCLUSION: It is possible to visualize urinary bladder tumours larger than 1 cm in diameter with PET using (11)C-methionine, but the value of the method in the staging of the lesions is not superior to conventional methods.
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| 25. |
- Ahlström, Håkan, et al.
(författare)
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Preoperative localization of endocrine pancreatic tumours by intra-arterial dynamic computed tomography
- 1990
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Ingår i: Acta Radiologica. - 0284-1851 .- 1600-0455. ; 31:2, s. 171-175
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Tidskriftsartikel (refereegranskat)abstract
- Eleven patients with biochemically confirmed endocrine pancreatic tumours were examined with intra-arterial (i.a.) dynamic computed tomography (CT) and angiography preoperatively. Seven of the patients suffered from the multiple endocrine neoplasia type 1 (MEN-1) syndrome. All patients were operated upon and surgical palpation and ultrasound were the peroperative localization methods. Of the 33 tumours which were found at histopathologic analysis of the resected specimens in the 11 patients, 7 tumours in 7 patients were correctly localized by both i.a. dynamic CT and angiography. Six patients with MEN-1 syndrome had multiple tumours and this group of patients together had 28 tumours, of which 5 (18%) were localized preoperatively by both CT and angiography. I.a. dynamic CT, with the technique used by us, does not seem to improve the localization of endocrine pancreatic tumours, especially in the rare group of MEN-1 patients, as compared with angiography.
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| 26. |
- Ahlström, Håkan, et al.
(författare)
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Pulmonary MR angiography with ultrasmall superparamagnetic iron oxide particles as a blood pool agent and a navigator echo for respiratory gating : pilot study
- 1999
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Ingår i: Radiology. - 0033-8419 .- 1527-1315. ; 211:3, s. 865-869
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Tidskriftsartikel (refereegranskat)abstract
- In nine healthy adult volunteers, pulmonary magnetic resonance angiography was performed with the blood pool agent NC100150 injection combined with respiratory gating with a navigator echo. With increasing doses of the contrast agent, higher signal intensities and vessel branch order visualization were achieved. No motion artifacts were seen. The blood pool agent NC100150 injection in combination with respiratory navigator gating permitted acquisition of high-quality MR angiograms of the pulmonary vasculature during continuous breathing.
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| 27. |
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| 28. |
- Ahlström, Håkan, et al.
(författare)
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The spatial distribution of parenterally administered monoclonal antibodies against CEA in a human colorectal tumour xenograft
- 1989
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Ingår i: Acta Oncologica. - 0284-186X .- 1651-226X. ; 28:1, s. 81-86
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Tidskriftsartikel (refereegranskat)abstract
- A recently developed experimental model consisting of athymic rats carrying human colonic tumours from the cell line LS 174 T in both hind legs was used. 125I-labelled anti-carcinoembryonic (anti-CEA) monoclonal antibodies were injected either intra-arterially after a bolus injection of mannitol, or intra-peritoneally with or without mannitol. On the fourth day the rats were killed and pieces from the tumours and various organs were measured in a well scintillation counter. Tumour pieces were then submitted to autoradiography and immunohistochemistry for examination of the antibody distribution at the cellular level. In all examined tumours injected with anti-CEA antibodies, most of the antibodies were located in the periphery close to fibrovascular septa. It appears, in addition to the specificity of the antibody for the CEA, that the tumour vascular permeability and anatomy are of utmost importance for tumour targeting in this experimental model with the particular antibody used.
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| 29. |
- Ahlström, Håkan, et al.
(författare)
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Vascularization of the continuous human colonic cancer cell line LS 174 T deposited subcutaneously in nude rats
- 1988
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Ingår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - 0903-4641 .- 1600-0463. ; 96:8, s. 701-710
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Tidskriftsartikel (refereegranskat)abstract
- The macro- and microvasculature of the human colonic cancer cell line LS 174 T, 2-8 weeks after subcutaneous deposition in both hind legs of congenitally athymic rats was investigated by light microscopy, angiography, and microvascular corrosion casting with analysis in a scanning electron microscope. The tumour blood vessels were connected to branches of the femoral artery. Only the outer 200-500 micron of the tumour was extensively vascularized, with several concentric, incomplete layers of tortuous vessels, resembling onion skin. Light microscopy revealed necrosis and bleeding in the centre of the tumour, especially in the older tumours, which corresponded well to the central avascularity observed in the casts. There was an increase in venular and capillary density and tortousity towards the tumour in the adjacent muscular fascia. It is concluded that the cell line LS 174 T grows invasively inwards and recruits its vessels from the nude rat host. The overall tumour vascular pattern was unorganized, suggesting limited control of new vessel formation. Extravasations of resin, which were encountered in all cast tumours, can be a rough indicator of enhanced vascular permeability.
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| 30. |
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| 31. |
- Ahmad, Nouman, et al.
(författare)
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Automatic segmentation of large-scale CT image datasets for detailed body composition analysis
- 2023
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Ingår i: BMC BIOINFORMATICS. - : BioMed Central (BMC). - 1471-2105. ; 24:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundBody 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.MethodsThe 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.ResultsThe 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.ConclusionFully 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.
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| 32. |
- Ahmad, Nouman, et al.
(författare)
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Voxel-wise body composition analysis using image registration of a three-slice CT imaging protocol : methodology and proof-of-concept studies
- 2024
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Ingår i: Biomedical engineering online. - : Springer Nature. - 1475-925X. ; 23:1
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Tidskriftsartikel (refereegranskat)abstract
- Background Computed tomography (CT) is an imaging modality commonly used for studies of internal body structures and very useful for detailed studies of body composition. The aim of this study was to develop and evaluate a fully automatic image registration framework for inter-subject CT slice registration. The aim was also to use the results, in a set of proof-of-concept studies, for voxel-wise statistical body composition analysis (Imiomics) of correlations between imaging and non-imaging data.Methods The current study utilized three single-slice CT images of the liver, abdomen, and thigh from two large cohort studies, SCAPIS and IGT. The image registration method developed and evaluated used both CT images together with image-derived tissue and organ segmentation masks. To evaluate the performance of the registration method, a set of baseline 3-single-slice CT images (from 2780 subjects including 8285 slices) from the SCAPIS and IGT cohorts were registered. Vector magnitude and intensity magnitude error indicating inverse consistency were used for evaluation. Image registration results were further used for voxel-wise analysis of associations between the CT images (as represented by tissue volume from Hounsfield unit and Jacobian determinant) and various explicit measurements of various tissues, fat depots, and organs collected in both cohort studies.Results Our findings demonstrated that the key organs and anatomical structures were registered appropriately. The evaluation parameters of inverse consistency, such as vector magnitude and intensity magnitude error, were on average less than 3 mm and 50 Hounsfield units. The registration followed by Imiomics analysis enabled the examination of associations between various explicit measurements (liver, spleen, abdominal muscle, visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), thigh SAT, intermuscular adipose tissue (IMAT), and thigh muscle) and the voxel-wise image information.Conclusion The developed and evaluated framework allows accurate image registrations of the collected three single-slice CT images and enables detailed voxel-wise studies of associations between body composition and associated diseases and risk factors.
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| 33. |
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| 34. |
- Alsaqal, Salem, et al.
(författare)
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The Combination of MR Elastography and Proton Density Fat Fraction Improves Diagnosis of Nonalcoholic Steatohepatitis.
- 2022
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Ingår i: Journal of Magnetic Resonance Imaging. - : John Wiley & Sons. - 1053-1807 .- 1522-2586. ; 56:2, s. -379
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is rapidly increasing worldwide. It is subdivided into nonalcoholic fatty liver (NAFL) and the more aggressive form, nonalcoholic steatohepatitis (NASH), which carries a higher risk of developing fibrosis and cirrhosis. There is currently no reliable non-invasive method for differentiating NASH from NAFL.PURPOSE: To investigate the ability of magnetic resonance imaging (MRI)-based imaging biomarkers to diagnose NASH and moderate fibrosis as well as assess their repeatability.STUDY TYPE: Prospective.SUBJECTS: Sixty-eight participants (41% women) with biopsy-proven NAFLD (53 NASH and 15 NAFL). Thirty participants underwent a second MRI in order to assess repeatability.FIELD STRENGTH/SEQUENCE: 3.0 T; MR elastography (MRE) (a spin-echo echo-planar imaging [SE-EPI] sequence with motion-encoding gradients), MR proton density fat fraction (PDFF) and R2* mapping (a multi-echo three-dimensional gradient-echo sequence), T1 mapping (a single-point saturation-recovery technique), and diffusion-weighted imaging (SE-EPI sequence).ASSESSMENT: Quantitative MRI measurements were obtained and assessed alone and in combination with biochemical markers (cytokeratin-18 [CK18] M30, alanine transaminase [ALT], and aspartate transaminase [AST]) using logistic regression models. Models that could differentiate between NASH and NAFL and between moderate to advanced fibrosis (F2-4) and no or mild fibrosis (F0-1), based on the histopathological results, were identified.STATISTICAL TESTS: Independent samples t-test, Pearson's chi-squared test, area under the receiver operating characteristic curve (AUROC), Spearman's correlation, intra-individual coefficient of variation, and intraclass correlation coefficient (ICC). Statistical significance was set at P < 0.05.RESULTS: There was a significant difference between the NASH and NAFL groups with liver stiffness assessed with MRE, CK18 M30, and ALT, with an AUROC of 0.74, 0.76, and 0.70, respectively. Both MRE and PDFF contributed significantly to a bivariate model for diagnosing NASH (AUROC = 0.84). MRE could significantly differentiate between F2-4 and F0-1 (AUROC = 0.74). A model combining MRE with AST improved the diagnosis of F2-4 (AUROC = 0.83). The ICC for repeatability was 0.94 and 0.99 for MRE and PDFF, respectively.DATA CONCLUSION: MRE can potentially diagnose NASH and differentiate between fibrosis stages. Combining MRE with PDFF improves the diagnosis of NASH.LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY: Stage 2.
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| 35. |
- Amini, Hashem, et al.
(författare)
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Second trimester fetal magnetic resonance imaging improves diagnosis of non-central nervous system anomalies
- 2011
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Ingår i: Acta Obstetricia et Gynecologica Scandinavica. - : Wiley. - 0001-6349 .- 1600-0412. ; 90:4, s. 380-389
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Tidskriftsartikel (refereegranskat)abstract
- Objectives. To evaluate the additional information of second trimester magnetic resonance imaging (MRI) compared to ultrasound in fetuses with identified or suspected non-CNS anomalies and to study the clinical impact of the MRI information on pregnancy management. Design. Prospective study during 2003-2007. The fetal MRI examination was planned to be performed within three days after the ultrasound. Setting. Uppsala University hospital. Material and methods. Sixty-three women, where the second trimester ultrasound identified or raised suspicion of fetal anomalies were included. Ultrasound was compared to MRI in relation to the final diagnosis, which was based on the assessment of all available data including post-partum clinical follow-up and autopsy results. Main outcome measures. Evaluation of the additional information gained from MRI and the consequences it had on pregnancy management. Results. The mean interval between ultrasound and MRI was 2.6 days (range 0-15). In 42 (67%) cases MRI was performed within three days. All MRI examinations were assessable. In 43 (68%) fetuses MRI provided no additional information, in 17 (27%) MRI added information without changing the management and in three (5%) MRI provided additional information which changed the management. All these three cases had oligohydramnios. In all six cases of diaphragmatic hernia MRI provided additional information. Conclusions. Fetal MRI of non-CNS anomalies in the second trimester seems to be a valuable adjunct to ultrasound diagnosis of non-CNS anomalies, especially in cases of oligohydramnios and diaphragmatic hernia.
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| 36. |
- Amini, Hashem, 1960-, et al.
(författare)
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The Clinical Impact of Fetal Magnetic Resonance Imaging on Management of Non-CNS Anomalies in the Second Trimester of Pregnancy
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Objectives: To evaluate the additional information of second trimester MRI compared to ultrasound in fetuses with identified or suspected non-CNS anomalies and to study the clinical impact of the MRI information on pregnancy management. Methods: Sixty-three women were included, where the second trimester ultrasound identified or raised suspicion of fetal anomalies. Ultrasound was compared to MRI in relation to the final diagnosis, fetal autopsy if performed or postnatal diagnosis. The additional information of MRI and effect on pregnancy management was estimated in consensus. Results: The mean gestational age at the last ultrasound before MRI was 18+1 weeks (range 13+0-21+5). The mean interval between ultrasound and MRI was 2.6 days (range 0-15). In 42 (67 %) cases MRI was performed within three days. All MRI examinations were assessable. In 43 (68 %) fetuses MRI provided no additional information, in 17 (27 %) MRI added information without changing the management and in three (5 %) MRI provided additional information which changed the management. These three cases had all oligohydramnios. In all six cases of diaphragmatic hernia MRI provided additional information. Conclusions: Fetal MRI of non-CNS anomalies is feasible in the second trimester and gives additional information in nearly a third of cases. It may provide a clinically valuable adjunct to ultrasound especially in cases of diaphragmatic hernia or oligohydramnios.
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| 37. |
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| 38. |
- Andersson, Camilla, et al.
(författare)
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Assessment of Whether Patients' Knowledge, Satisfaction, and Experience Regarding Their 18F-Fluoride PET/CT Examination Affects Image Quality
- 2016
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Ingår i: Journal of Nuclear Medicine Technology. - : Society of Nuclear Medicine. - 0091-4916 .- 1535-5675. ; 44:1, s. 21-25
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate patients’ previous knowledge, satisfaction and experience regarding a (18F)-fluoride positron emission tomography / computed tomography examination ((18F)-fluoride PET/CT) and to explore whether experienced discomfort during the examination or pain was associated with reduced image quality. A further aim was to explore whether patients’ health-related quality of life (HRQoL) was associated with their satisfaction and experiences of the examination.Methods: Fifty consecutive patients with a histopathological diagnosis of prostate cancer who were scheduled for (18F)-fluoride PET/CT were asked to participate in the study, which was performed between November 2011 and April 2013. A questionnaire was used to collect information regarding the patients’ previous knowledge and experience of the examination. Image quality assessment was performed according to an arbitrary scale. The EORTC-QLQ-C30 and QLQ-PR25 were used to assess HRQoL.Results: Forty-six patients (96%) completed the questionnaires. Twenty-six per cent of participants did not know at all what a (18F)-fluoride PET/CT examination was. The majority (52-70%) were to a very high degree satisfied with the care provided by the nursing staff but less satisfied with the information given prior to the examination. The image quality was similar in patients who were exhausted or claustrophobic during the examination and those who were not. No correlations between HRQoL and the participants’ experience of (18F)-fluoride PET/CT were found.Conclusion: The majority of participants were satisfied with the care provided by the nursing staff, but there is still room for improvement especially regarding the information prior to the examination. Long examination time may be strenuous, for the patient but there was no difference in image quality between patients who felt discomfort during the examination or pain and those who did not.
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| 39. |
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| 40. |
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| 41. |
- Andersson, Camilla, et al.
(författare)
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Patient Experience of an 18F-FDG-PET/CT Examination: : Need for Improvements in Patient Care
- 2015
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Ingår i: Journal of Radiology Nursing. - : Elsevier. - 1546-0843. ; 34:2, s. 100-108
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Tidskriftsartikel (refereegranskat)abstract
- The aims of this study were to investigate the patients' knowledge about and experience of an 18F-fluoro-deoxy-glucose (FDG)-positron emission tomography (PET)/computed tomography (CT) examination and to investigate the self-reported feelings of stress, level of physical activity, and health-related quality of life (HRQoL) and to find out if this was related to how they experienced the examination. A cross-sectional survey was used to collect information on 198 patients with known or suspected malignancy. As many as 32% to 63% were satisfied with the nursing staff, the communication, and the professional skills. Most patients did not know beforehand what an FDG-PET/CT examination was. The HRQoL, level of perceived stress, and physical activity were relatively low. A better HRQoL, lower level of perceived stress, and a higher level of physical activity were correlated to a more positive experience and higher education to more knowledge about the examination (p < .01–.05). The information before the examination needs to be improved. The results may be used to improve patient care and optimize imaging procedures.
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| 42. |
- Andersson, Camilla
(författare)
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PET/CT in oncology : Patient experience, image quality and the value of information
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The overall aim was to investigate patients’ experiences with a PET/CT examination, satisfaction with care provided in connection to the examination and whether web-based information can improve satisfaction with care and image quality, compared to standard care. An additional aim was to explore how satisfaction with care and image quality is associated with health-related quality of life (HRQoL) and perceived stress. Methods: Study I and IV included patients with known or suspected malignancy scheduled for an 18F-FDG PET/CT examination. Study II included prostate cancer patients with known or suspected bone metastases scheduled for an 18F-fluoride PET/CT examination, and study III included head and neck cancer patients scheduled for an 18F-FDG PET/CT examination in a fixation mask. Study I and II had cross-sectional designs, study III used a phenomenological methodology according to Max van Manen, and study IV was a randomized controlled trial. Results: Study I and II found that many patients did not know before what a PET/CT examination was but were satisfied with care provided by the nursing staff. In study II the image quality was high and there was no difference in image quality between those patients that experienced pain or discomfort during the PET/CT and those that did not. Study III showed that the patient’s lifeworld was changed during the PET/CT examination and the use of coping strategies helped the patient to endure the examination procedure. In study IV the overall satisfaction, satisfaction single-variables and image quality was high in the intervention group and standard care group. There was no statistically significant difference between patients the intervention group and standard care group. However, there was slightly higher number of detected image quality defects in the standard care group. In study I and IV there were some statistically significant correlations between patient satisfaction and HRQoL (p<0.01-0.05). Conclusion: The results of this thesis may be used to improve patient information and care in connection to PET/CT examinations and thereby help optimize PET/CT imaging procedure. However, the results need to be investigated in larger populations.
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| 43. |
- Andersson, Camilla, et al.
(författare)
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Randomized Controlled Trial Examining Effects of Web-Based Information on Patient Satisfaction and Image Quality in 18F-FDG PET/CT Examinations
- 2019
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Ingår i: Journal of Nuclear Medicine Technology. - : Society of Nuclear Medicine. - 0091-4916 .- 1535-5675. ; :1, s. 36-46
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Tidskriftsartikel (refereegranskat)abstract
- Our aim was to compare the effect that having access, versus not having access, to web-based patient information on 18F-FDG PET/CT has on image quality and on patient satisfaction with their care during and knowledge about the examination, as well as to explore whether patients utilized and were satisfied with the web-based information.Methods: We recruited 148 patients between October 2015 and December 2016 and randomly assigned them to a standard-care group or an intervention group. Both groups received standard information about the 18F-FDG PET/CT examination, but the intervention group also received access to web-based information. A questionnaire was used to evaluate patient satisfaction with, knowledge about, and discomfort during the examination, and a masked assessment of image quality was conducted.Results: Overall satisfaction was high in both groups. The lowest satisfaction was with information about how the patients would receive the results of the examination. More patients in the intervention group than in the standard-care group knew how the 18F-FDG PET/CT examination would be conducted. Descriptive data suggest that image quality was slightly better in the intervention group than in the standard-care group, but none of the outcomes significantly differed between the groups. However, several obstacles were encountered during recruitment that led to insufficient power to detect differences. Also, only 54 of 75 patients (72%) in the intervention group utilized the web-based information. However, those who did utilize the information were satisfied with it and found it helpful.Conclusion: The effects of web-based information need to be investigated in a larger sample of patients. Having access to improved information before undergoing 18F-FDG PET/CT may help patients prepare for and undergo the examination. It may also improve image quality. However, this possibility needs to be investigated using image quality as the primary outcome. The results may be used to improve patient information and care and thereby optimize the 18F-FDG PET/CT procedure.
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| 44. |
- Andersson, Jonathan, et al.
(författare)
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Estimating the cold-induced brown adipose tissue glucose uptake rate measured by 18F-FDG PET using infrared thermography and water-fat separated MRI
- 2019
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Brown adipose tissue (BAT) expends chemical energy to produce heat, which makes it a potential therapeutic target for combating metabolic dysfunction and overweight/obesity by increasing its metabolic activity. The most well-established method for measuring BAT metabolic activity is glucose uptake rate (GUR) measured using 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET). However, this is expensive and exposes the subjects to potentially harmful radiation. Cheaper and safer methods are warranted for large-scale or longitudinal studies. Potential alternatives include infrared thermography (IRT) and magnetic resonance imaging (MRI). The aim of this study was to evaluate and further develop these techniques. Twelve healthy adult subjects were studied. The BAT GUR was measured using 18F-FDG PET during individualized cooling. The temperatures of the supraclavicular fossae and a control region were measured using IRT during a simple cooling protocol. The fat fraction and effective transverse relaxation rate of BAT were measured using MRI without any cooling intervention. Simple and multiple linear regressions were employed to evaluate how well the MRI and IRT measurements could estimate the GUR. Results showed that both IRT and MRI measurements correlated with the GUR. This suggest that these measurements may be suitable for estimating the cold-induced BAT GUR in future studies.
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| 45. |
- Andersson, Jonathan, et al.
(författare)
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MRI estimates of brown adipose tissue in children - Associations to adiposity, osteocalcin, and thigh muscle volume
- 2019
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Ingår i: Magnetic Resonance Imaging. - : Elsevier BV. - 0730-725X .- 1873-5894. ; 58, s. 135-142
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Tidskriftsartikel (refereegranskat)abstract
- Context Brown adipose tissue is of metabolic interest. The tissue is however poorly explored in children. Methods: Sixty-three 7-year old subjects from the Swedish birth-cohort Halland Health and Growth Study were recruited. Care was taken to include both normal weight and overweight children, but the subjects were otherwise healthy. Only children born full term were included. Water-fat separated whole-body MRI scans, anthropometric measurements, and measurements of fasting glucose and levels of energy homeostasis related hormones, including the insulin-sensitizer osteocalcin, were performed. The fat fraction (FF) and effective transverse relaxation time (T-2(star)) of suspected brown adipose tissue in the cervical-supraclavicular-axillary fat depot (sBAT) and the FFs of abdominal visceral (VAT) and subcutaneous adipose tissue (SAT) were measured. Volumes of sBAT, abdominal VAT and SAT, and thigh muscle volumes were measured. Results: The FF in the sBAT depot was lower than in VAT and SAT for all children. In linear correlations including sex and age as explanatory variables, sBAT FF correlated positively with all measures of adiposity (p < 0.01), except for VAT FF and weight, positively with sBAT T-2* (p = 0.036), and negatively with osteocalcin (p = 0.017). When adding measures of adiposity as explanatory variables, sBAT FF also correlated negatively with thigh muscle volume (p < 0.01). Conclusions: Whole-body water-fat MRI of children allows for measurements of sBAT. The FF of sBAT was lower than that of VAT and SAT, indicating presence of BAT. Future studies could confirm whether the observed correlations corresponds to a hormonally active BAT.
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| 46. |
- Andersson, Jonathan, et al.
(författare)
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Separation of water and fat signal in whole-body gradient echo scans using convolutional neural networks
- 2019
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Ingår i: Magnetic Resonance in Medicine. - : Wiley. - 0740-3194 .- 1522-2594. ; 82:3, s. 1177-1186
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To perform and evaluate water–fat signal separation of whole‐body gradient echo scans using convolutional neural networks.Methods: Whole‐body gradient echo scans of 240 subjects, each consisting of 5 bipolar echoes, were used. Reference fat fraction maps were created using a conventional method. Convolutional neural networks, more specifically 2D U‐nets, were trained using 5‐fold cross‐validation with 1 or several echoes as input, using the squared difference between the output and the reference fat fraction maps as the loss function. The outputs of the networks were assessed by the loss function, measured liver fat fractions, and visually. Training was performed using a graphics processing unit (GPU). Inference was performed using the GPU as well as a central processing unit (CPU).Results: The loss curves indicated convergence, and the final loss of the validation data decreased when using more echoes as input. The liver fat fractions could be estimated using only 1 echo, but results were improved by use of more echoes. Visual assessment found the quality of the outputs of the networks to be similar to the reference even when using only 1 echo, with slight improvements when using more echoes. Training a network took at most 28.6 h. Inference time of a whole‐body scan took at most 3.7 s using the GPU and 5.8 min using the CPU.Conclusion: It is possible to perform water–fat signal separation of whole‐body gradient echo scans using convolutional neural networks. Separation was possible using only 1 echo, although using more echoes improved the results.
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| 47. |
- Andersson, Jonathan, et al.
(författare)
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Water-fat separation incorporating spatial smoothing is robust to noise
- 2018
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Ingår i: Magnetic Resonance Imaging. - : Elsevier BV. - 0730-725X .- 1873-5894. ; 50, s. 78-83
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To develop and evaluate a noise-robust method for reconstruction of water and fat images for spoiled gradient multi-echo sequences.METHODS: The proposed method performs water-fat separation by using a graph cut to minimize an energy function consisting of unary and binary terms. Spatial smoothing is incorporated to increase robustness to noise. The graph cut can fail to find a solution covering the entire image, in which case the relative weighting of the unary term is iteratively increased until a complete solution is found. The proposed method was compared to two previously published methods. Reconstructions were performed on 16 cases taken from the 2012 ISMRM water-fat reconstruction challenge dataset, for which reference reconstructions were provided. Robustness towards noise was evaluated by reconstructing images with different levels of noise added. The percentage of water-fat swaps were calculated to measure performance.RESULTS: At low noise levels the proposed method produced similar results to one of the previously published methods, while outperforming the other. The proposed method significantly outperformed both of the previously published methods at moderate and high noise levels.CONCLUSION: By incorporating spatial smoothing, an increased robustness towards noise is achieved when performing water-fat reconstruction of spoiled gradient multi-echo sequences.
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| 48. |
- Andersson, Jonathan
(författare)
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Water–fat separation in magnetic resonance imaging and its application in studies of brown adipose tissue
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Virtually all the magnetic resonance imaging (MRI) signal of a human originates from water and fat molecules. By utilizing the property chemical shift the signal can be separated, creating water- and fat-only images. From these images it is possible to calculate quantitative fat fraction (FF) images, where the value of each voxel is equal to the percentage of its signal originating from fat. In papers I and II methods for water–fat signal separation are presented and evaluated.The method in paper I utilizes a graph-cut to separate the signal and was designed to perform well even for a low signal-to-noise ratio (SNR). The method was shown to perform as well as previous methods at high SNRs, and better at low SNRs.The method presented in paper II uses convolutional neural networks to perform the signal separation. The method was shown to perform similarly to a previous method using a graph-cut when provided non-undersampled input data. Furthermore, the method was shown to be able to separate the signal using undersampled data. This may allow for accelerated MRI scans in the future.Brown adipose tissue (BAT) is a thermogenic organ with the main purpose of expending chemical energy to prevent the body temperature from falling too low. Its energy expending capability makes it a potential target for treating overweight/obesity and metabolic dysfunctions, such as type 2 diabetes. The most well-established way of estimating the metabolic potential of BAT is through measuring glucose uptake using 18F-fludeoxyglucose (18F-FDG) positron emission tomography (PET) during cooling. This technique exposes subjects to potentially harmful ionizing radiation, and alternative methods are desired. One alternative method is measuring the BAT FF using MRI.In paper III the BAT FF in 7-year olds was shown to be negatively associated with blood serum levels of the bone-specific protein osteocalcin and, after correction for adiposity, thigh muscle volume. This may have implications for how BAT interacts with both bone and muscle tissue.In paper IV the glucose uptake of BAT during cooling of adult humans was measured using 18F-FDG PET. Additionally, their BAT FF was measured using MRI, and their skin temperature during cooling near a major BAT depot was measured using infrared thermography (IRT). It was found that both the BAT FF and the temperature measured using IRT correlated with the BAT glucose uptake, meaning these measurements could be potential alternatives to 18F-FDG PET in future studies of BAT.
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| 49. |
- Andrén, Ulla, 1955-, et al.
(författare)
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Utveckling av ett nytt yrke inom socialpsykiatrisk vård
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The program in Social Psychiatric Care is a three-year program at the university level leading to a vocational qualification in social psychiatric care and a bachelor's degree in the field of Health Sciences. Until the spring of 2018, six litters have graduated. Students in the social psychiatric care program often have personal interest, previous professional experience from the business areas or inspiration from related friends working in the field of activity. Personal experiences of problems in the fields of activity are also prominent among the students. Students believe that personal experience, willingness and ability is important in order to work within the profession. Characteristics of the students are also an interest and a clear empathetic willingness to work with people and they consider that the profession primarily requires characteristics such as altruism, empathy, social skills and deeper knowledge and understanding in the field. Upon completion of education, students want a career role where they can help other people, feel motivated, or they aim for specific positions or areas of activity. Both managers and alumni from the Social Psychiatric Care program value the broad professional competence that the program leads to. Psychiatric competence is emphasized as particularly valuable by both alumni and managers. This competence means that they also complement the other professions in the activities. Students consider themselves possessed a professional identity that involves introducing psychiatric and custody skills to organizations that previously lacked these perspectives. Something that also brings new approaches to patients, users and clients. Being able to use knowledge from several disciplines are considered to be a strength and competence that are well-needed in environments where people with mental ill health are cared for. The alumni perceive their knowledge as both interdisciplinary and interprofessional.
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- Benedict, Christian, et al.
(författare)
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Association between physical activity and brain health in older adults
- 2013
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 34:1, s. 83-90
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Tidskriftsartikel (refereegranskat)abstract
- In the present cross-sectional study, we examined physical activity (PA) and its possible association with cognitive skills and brain structure in 331 cognitively healthy elderly. Based on the number of self-reported light and hard activities for at least 30 minutes per week, participants were assigned to 4 groups representing different levels of PA. The cognitive skills were assessed by the Mini Mental State Examination score, a verbal fluency task, and the Trail-making test as a measure of visuospatial orientation ability. Participants also underwent a magnetic resonance imaging of the brain. Multiple regression analysis revealed that greater PA was associated with a shorter time to complete the Trail-making test, and higher levels of verbal fluency. Further, the level of self-reported PA was positively correlated with brain volume, white matter, as well as a parietal lobe gray matter volume, situated bilaterally at the precuneus. These present cross-sectional results indicate that PA is a lifestyle factor that is linked to brain structure and function in late life.
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