| 1. |
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| 2. |
- Andersson, Jesper L, et al.
(författare)
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A method for coregistration of PET and MR brain images
- 1995
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Ingår i: Journal of Nuclear Medicine. - 0161-5505 .- 1535-5667. ; 36:7, s. 1307-1315
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Tidskriftsartikel (refereegranskat)abstract
- Combining MRI morphological data with functional PET data offers significant advantages in research as well as in many clinical situations. Automatic methods are needed, however, to coregister the data from the two modalities.METHODS:Simulated PET images were created by simple and automatic segmentation of MR images followed by the assignment of different uptake values to various tissue types. The simulated PET images were registered to actual PET images using a pixel-by-pixel, PET-PET registration method. The transformation matrix was then applied to the MR images. The method was used to register MRI data to PET transmission scans and emission scans obtained with FDG, nomifensine and raclopride. Validation was performed by comparing the results to those obtained by matching internal points manually defined in both volumes.RESULTS:Emission and transmission PET images were successfully registered to MR data. Comparison to the manual method indicated a registration accuracy on the order of 1-2 mm in each direction. No difference in accuracy between the different tracers was found. The error sensitivity for the method's assumptions seemed to be sufficiently low to allow complete automation of the method.CONCLUSION:We present a rapid, robust and fully automated method to register PET and MR brain images with sufficient accuracy for most clinical applications.
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| 3. |
- Beshara, Soheir, et al.
(författare)
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Kinetic analysis of 52Fe-labelled iron(III) hydroxide-sucrose complex following bolus administration using positron emission tomography
- 1999
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Ingår i: British Journal of Haematology. - : Wiley. - 0007-1048 .- 1365-2141. ; 104:2, s. 288-295
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Tidskriftsartikel (refereegranskat)abstract
- Kinetic analysis of a single intravenous injection of 100 mg iron(III) hydroxide-sucrose complex (Venofer) mixed with 52Fe(III) hydroxide-sucrose as a tracer was followed for 3-6 h in four generally anaesthetized, artificially ventilated minipigs using positron emission tomography (PET). The amount of injected radioactivity ranged from 30 to 200 MBq. Blood radioactivity, measured by PET in the left ventricle of the heart, displayed a fast clearance phase followed by a slow one. In the liver and bone marrow a fast radioactivity uptake occurred during the first 30 min, followed by a slower steady increase. In the liver a slight decrease in radioactivity uptake was noted by the end of the study. A kinetic analysis using a three-compartment (namely blood pool, reversible and irreversible tissue pools) model showed a fairly high distribution volume in the liver as compared with the bone marrow. In conclusion, the pharmacokinetics of the injected complex was clearly visualized with the PET technique. The organs of particular interest, namely the heart (for blood kinetics), liver and bone marrow could all be viewed by a single setting of a PET tomograph with an axial field of view of 10 cm. The half-life (T1/2) of 52Fe (8.3 h) enables a detailed kinetic study up to 24 h. A novel method was introduced to verify the actual 52Fe contribution to the PET images by removing the interfering radioactive daughter 52mMn positron emissions. The kinetic data fitted the three-compartment model, from which rate constants could be obtained for iron transfer from the blood to a pool of iron in bone marrow or liver to which it was bound during the study period. In addition, there was a reversible tissue pool of iron, which in the liver slowly equilibrated with the blood, to give a net efflux from the liver some hours after i.v. administration. The liver uptake showed a relatively long distribution phase, whereas the injected iron was immediately incorporated into the bone marrow. Various transport mechanisms seem to be involved in the handling of the injected iron complex.
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| 4. |
- Beshara, Soheir, et al.
(författare)
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Pharmacokinetics and red cell utilization of iron(III) hydroxide- sucrose complex in anaemic patients: a study using positron emission tomography
- 1999
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Ingår i: British Journal of Haematology. - : Wiley. - 0007-1048 .- 1365-2141. ; 104:2, s. 296-302
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Tidskriftsartikel (refereegranskat)abstract
- The pharmacokinetics of a single intravenous injection of 100 mg iron hydroxide-sucrose complex labelled with a tracer in the form of 52Fe/59Fe was followed in six anaemic patients for a period ranging from 6 to 8 3 h using positron emission tomography (PET). Red cell utilization of the labelled iron was followed for 4 weeks. PET data showed radioactive uptake by the liver, spleen and bone marrow. The uptake by the macrophage-rich spleen demonstrated the reticuloendothelial uptake of this iron preparation, with subsequent effective release of that iron for marrow utilization. Red cell utilization, followed for 4 weeks, ranged from 59% to 97%. The bone marrow influx rate constant was independent of blood iron concentration, indicating non-saturation of the transport system in bone marrow. This implied that higher doses of the iron complex can probably be used in the same setting. A higher influx rate into the marrow compared with the liver seemed to be consistent with higher red cell utilization. This would indicate that early distribution of the injected iron complex may predict the long-term utilization.
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| 5. |
- Dencker, Magnus, et al.
(författare)
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Primary lung tumour visualised by transthoracic echocardiography
- 2008
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Ingår i: Cardiovascular Ultrasound. - : Springer Science and Business Media LLC. - 1476-7120. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- We present images of a rare case where a primary lung tumour was visualised by transthoracic echocardiography. The patient was a 78-year-old male where Chest X-ray had revealed a tumour-suspected structure in the left lung. Both transthoracic echocardiography and combined PET/CT images showed a large tumour located close to the heart. Fine-needle biopsy showed non-small cell lung cancer.
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| 6. |
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| 7. |
- Dencker, Magnus, et al.
(författare)
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Right ventricular metastasis of leiomyosarcoma.
- 2009
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Ingår i: Cardiovascular Ultrasound. - : Springer Science and Business Media LLC. - 1476-7120. ; 7:May 5
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Tidskriftsartikel (refereegranskat)abstract
- Metastatic presentation of leiomyosarcoma in the heart is very rare. We present transthoracic echocardiography and combined PET/CT images of a case with a large right ventricular metastasis of leiomyosarcoma. The patient was placed on cytostatic drugs for palliative purposes, but passed away one month later because of an untreatable ventricular tackycardia.
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| 8. |
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| 9. |
- Edling, Christer, et al.
(författare)
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Positron emission tomography studies of healthy volunteers : No effects on the dopaminergic terminals and synthesis after short-term exposure to toluene
- 1997
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Ingår i: Human and Experimental Toxicology. - : SAGE Publications. - 0960-3271 .- 1477-0903. ; 16:3, s. 171-176
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Tidskriftsartikel (refereegranskat)abstract
- Despite extensive research, the mechanisms for the effects of organic solvents on the central nervous system are still unknown. One mechanism proposed is that solvents interfere with the synthesis of neurotransmitters. In the present study 11 male healthy volunteers were exposed during 15 min to 100 p.p.m. toluene at light physical exercise, and the dopamine decarboxylase activity and number of terminals in putamen were measured before and after exposure by positron emission tomography. Two different tracers were used [beta-11C]L-DOPA for decarboxylase activity during the in vivo synthesis of dopamine, and [11C]nomifensine to estimate the number of terminals. Although there was a slight increase in the rate of dopamine synthesis in the putamen after the exposure, this difference was not statistically significant (P = 0.4). No effect was observed with regard to the uptake of nomifensine. There was no significant relationship between the dose of toluene and rate of dopamine synthesis, and no significant correlation between the time from end of exposure to start of the PET-camera and DOPA. Our findings indicate that short term exposure to 100 p.p.m. of toluene does not affect the rate of dopamine synthesis or the number of presynaptic terminals.
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| 10. |
- Engström, Gunnar, et al.
(författare)
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Asymptomatic leg and carotid atherosclerosis in smokers is related to degree of ventilatory capacity: longitudinal and cross-sectional results from 'Men born in 1914', Sweden
- 2001
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Ingår i: Atherosclerosis. - 1879-1484. ; 155:1, s. 237-243
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Tidskriftsartikel (refereegranskat)abstract
- Although smoking is associated with cardiovascular disease (CVD), many individuals remain healthy after many years of smoking. The population based cohort 'Men born in 1914' was used to investigate whether the occurrence of non-invasively detected atherosclerosis among smokers is associated with lung function [(i.e. height-adjusted forced expiratory volume during 1 s (FEV1.0) and vital capacity (VC)]. Two hundred and seven smokers without history of CVD were examined with spirometry and calf plethysmography at 55 years, and with spirometry, ankle-arm blood pressure recordings and ultrasound examinations of the carotid arteries at 68 years. Eighty-three men had atherosclerosis defined as carotid stenosis >30% or ankle-arm index <0.9. FEV1.0 and VC were both at 55 years (longitudinally) and at 68 years (cross-sectionally) lower among men with atherosclerosis at 68 years (55 years: FEV1.0, 3.2+/-0.6 vs. 3.4+/-0.5 l; P=0.02; VC, 4.2+/-0.5 vs. 4.4+/-0.5 l; P=0.02; 68 years: FEV1.0, 2.6+/-0.6 vs. 2.9+/-0.7 l; P=0.004; VC, 3.8+/-0.6 vs. 4.0+/-0.6; P=0.009, for men with and without atherosclerosis). The longitudinal and cross-sectional associations between FEV1.0, VC and atherosclerosis remained significant after adjustments for several potential confounders (tobacco consumption at 55 and 68 years, hypertension, diabetes, alcohol consumption at 68 years, and pulse wave amplitude as a measure of degree of atherosclerosis at 55 years). We conclude that the risk of developing atherosclerosis is associated with the degree of ventilatory capacity. The results suggest that in smokers, reduced lung function is a marker of susceptibility for atherosclerosis.
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| 11. |
- Engström, Gunnar, et al.
(författare)
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Blood pressure increase between 55 and 68 years of age is inversely related to lung function: longitudinal results from the cohort study 'Men born in 1914'
- 2001
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Ingår i: Journal of Hypertension. - 1473-5598. ; 19:7, s. 1203-1208
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Although age is associated with increasing blood pressure, there is a substantial heterogeneity within a certain birth cohort. Whether increase in systolic and diastolic blood pressure is related to pulmonary function is largely unknown. OBJECTIVE: To study blood pressure elevation between 55 and 68 years of age in relation to vital capacity (VC) and forced expiratory volume (FEV1.0) at 55. DESIGN: Population-based cohort study. PARTICIPANTS: A total of 375 men without antihypertensive medication at baseline. MAIN OUTCOME MEASURE: Change in systolic blood pressure (SBP) and diastolic blood pressure (DBP) over 13 years. RESULTS: Blood pressure increase between 55 and 68 years was highest among men who at 55 years had low vital capacity. Average increase in systolic blood pressure for men with vital capacity in the first, second, third and fourth quartile was 20.4, 18.7, 16.5 and 11.1 mmHg, respectively (P for trend = 0.005). Average increase in diastolic blood pressure was 10.6, 9.9, 9.0 and 6.3 mmHg, respectively (P= 0.02). The trends remained statistically significant after adjustments for baseline blood pressure, tobacco consumption, smoking cessation between 55 and 68, weight change between 55 and 68, physical activity and diabetes. Further analysis showed that the relationships could be found among men with blood pressures < or = 140/ 90 mmHg at baseline, whereas no significant association was found for men whose baseline SBP or DBP exceeded 140/90 mmHg. FEV1.0 showed similar associations with change in blood pressure. CONCLUSION: Lung function is inversely associated with future blood pressure increase. It is suggested that this association could contribute to the relationships between lung function and incidence of cardiovascular disease.
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| 12. |
- Engström, Gunnar, et al.
(författare)
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Increased incidence of myocardial infarction and stroke in hypertensive men with reduced lung function
- 2001
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Ingår i: Journal of Hypertension. - 1473-5598. ; 19:2, s. 295-301
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND OBJECTIVE: Although hypertension is associated with increased cardiovascular risk, many individuals remain free from disease. This study is aimed to investigate whether this variation in individual susceptibility is associated with lung function. DESIGN: Population-based prospective cohort study. PARTICIPANTS: 'Men born in 1914', Malmo, Sweden. Subjects (n = 639) were examined and considered free from prevalent cardiovascular disease at age 55 years. MAIN OUTCOME MEASURES: Mortality, fatal and non-fatal stroke and cardiac events (fatal or non-fatal myocardial infarction) during 28-years follow-up. RESULTS: Of the men, 467 had normal blood pressure and 172 (27%) had hypertension (> or = 160/95 mmHg or treatment for hypertension). Hypertensive men with height-adjusted forced expiratory volume during 1 s (FEV1.0) below median had significantly higher rates of stroke (13.4 versus 5.8/1,000 person-years), cardiac events (27.1 versus 12.8/1,000 person-years) and all cause mortality (52.5 versus 28.6/1,000 person-years) than hypertensive men with high FEV1.0. These differences remained statistically significant after adjustment for potential confounders. Men with normal blood pressure and FEV1.0 below median had higher rates of stroke (5.4 versus 4.2/1,000 person-years), cardiac events (13.3 versus 11.6/1,000 person-years) and all cause mortality (29.9 versus 21.2/1,000 person-years) than men with normal blood pressure and high FEV1.0. After adjustments for potential confounders, FEV1.0 was significantly associated with mortality among men with normal blood pressure, whereas the associations with stroke and cardiac events did not reach significance. CONCLUSION: The incidence of cardiovascular disease and death associated with hypertension is increased among men with reduced lung function. The synergistic interaction between hypertension and lung function was independent of smoking and other potential confounders.
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| 13. |
- Engström, Gunnar, et al.
(författare)
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Occurrence and prognostic significance of ventricular arrhythmia is related to pulmonary function: a study from "men born in 1914," Malmo, Sweden
- 2001
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Ingår i: Circulation. - 1524-4539. ; 103:25, s. 3086-3091
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Reduced lung function has been associated with increased rates of myocardial infarction. Whether the occurrence and prognostic significance of ventricular arrhythmia is related to lung function is largely unknown. METHODS AND RESULTS: We performed a population-based study of 68-year-old men without a history of stroke or myocardial infarction; 402 men participated. Mortality and coronary events (fatal or nonfatal) were studied in relation to ventricular arrhythmia during 24 hours, percentage of the predicted forced expiratory volume (FEV1(%pred)), vital capacity (VC(%pred)), and the FEV/VC ratio. During 14 years of follow-up, 181 men died and 87 experienced a coronary event. Occurrence of frequent or complex ventricular arrhythmia (Lown class 2 to 5) was significantly and inversely associated with FEV1(%pred). Men with Lown class 2 to 5 and a low FEV1(%pred) (below median) had significantly higher mortality (71.5 versus 26.8 per 1000 person-years; P<0.0001) and coronary event rates (37.7 versus 18.0; P=0.02) than men with Lown class 2 to 5 and a high FEV1(%pred). These associations remained significant after adjustments for potential confounders (mortality: relative risk [RR], 2.91; 95% CI,1.68 to 5.04; coronary events: RR, 2.16; 95% CI, 1.07 to 4.37). In men without frequent or complex arrhythmia (Lown 0 to 1), a low FEV1(%pred) was not significantly associated with mortality (RR, 1.37; 95% CI, 0.92 to 2.05) or coronary events (RR, 1.24; 95% CI, 0.67 to 2.27) after adjustments for confounders. The FEV/VC ratio showed similar associations with arrhythmia, mortality, and coronary events. CONCLUSIONS: Lung function is inversely associated with the occurrence of ventricular arrhythmia. The increased incidence of myocardial infarction and death associated with arrhythmia was mainly limited to men with a low FEV1(%pred) or FEV/VC. We suggest that lung function should be considered when assessing the prognostic significance of ventricular arrhythmia.
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| 14. |
- Frostfeldt, Gunnar, et al.
(författare)
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Development of myocardial microcirculation and metabolism in acute ST-elevation myocardial infarction evaluated with positron emission tomography
- 2005
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Ingår i: Journal of Nuclear Cardiology. - : Springer Science and Business Media LLC. - 1071-3581 .- 1532-6551. ; 12:1, s. 43-54
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Early reperfusion is an established therapeutic objective in acute myocardial infarction (MI). The relationship of regional myocardial microcirculation and metabolism toward outcome in acute human MI is not well known.METHODS AND RESULTS: In 8 patients, positron emission tomography (PET) was performed with oxygen 15-labeled water at 3 hours, 24 hours, and 3 weeks after the start of fibrinolytic treatment, with carbon 11 acetate at 3 hours and with fluorine 18 fluorodeoxyglucose at 24 hours and 3 weeks. Absolute quantification of perfusion and water-perfusable tissue fraction (PTF), metabolic activity, and substrate extraction in 4 regions of interest was performed. Coronary angiography was performed at 24 hours. Short-term outcome at 3 weeks was evaluated by contractile reserve with dobutamine stress echocardiography and lung water measurements with PET. Early regional perfusion, PTF, and extraction and utilization of oxygen and glucose decreased closer to the infarct region ( P < .001 for all). Infarct-related oxygen utilization and extraction of oxygen and glucose were closely related to outcome ( P < .01 for all). PTF improved significantly in the infarct-related regions over time in proportion to early oxygen extraction and utilization.CONCLUSIONS: This pilot study indicates that PET might be useful in the evaluation of treatment efficacy and that restoration of oxidative metabolism is more closely related to myocardial damage recovery than perfusion in the early phase after MI.
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| 15. |
- Garpered, Sabine, et al.
(författare)
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Evaluation of 18F-FDG uptake in lung parenchyma compensating for tissue fraction : Comparison between non-enhanced low dose CT and intravenous contrast-enhanced diagnostic CT
- 2020
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Ingår i: Nuklearmedizin. - : Georg Thieme Verlag KG. - 0029-5566 .- 2567-6407. ; 59:1, s. 20-25
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Tidskriftsartikel (refereegranskat)abstract
- AIM: To determine how the presence of intravenous (IV) contrast-enhanced CT influences SUV measurements corrected for both attenuation and tissue fraction. MATERIAL AND METHODS: Eighteen patients with different malignancies, free from lung disorders, lung cancer or metastasis, were prospectively recruited when referred for staging with combined 18F-FDG-PET/CT examination. A non-enhanced low-dose CT over the chest was immediately followed by a whole-body IV contrast-enhanced diagnostic CT and finally the PET acquisition. PET data were reconstructed with attenuation correction based on the two CT data sets. The lungs were segmented in the CT images and lung density was measured. Uptake of 18F-FDG in lung parenchyma was recorded using both non-enhanced and IV contrast-enhanced CT as well as with and without compensation for lung aeration. A comparison of SUV values of corrected and uncorrected PET images was performed. RESULTS: There was no significant difference between low dose PET/CT and IV contrast-enhanced PET/CT when removing the impact of air fraction (p = 0.093 for the right lung and p = 0.085 for the left lung). When tissue fraction was not corrected for, there was a significant difference between low dose PET/CT and IV contrast enhanced PET/CT used for attenuation correction (p = 0.006 for the right lung and p = 0.015 for the left lung). CONCLUSION: There was only a marginal effect on the assessement of SUV in the lung tissue when using IV contrast enhanced CT for attenuation correction when the air fraction was accounted for.
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| 16. |
- Garpered, Sabine, et al.
(författare)
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Measurement of airway inflammation in current smokers by positron emission tomography
- 2019
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Ingår i: Clinical Physiology and Functional Imaging. - : Wiley. - 1475-0961 .- 1475-097X. ; 39:6, s. 393-398
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Tidskriftsartikel (refereegranskat)abstract
- Background Accumulation of activated neutrophilic leucocytes is known to increase uptake of F-18-fluorodeoxyglucose (F-18-FDG) into lung tissue. Available evidence suggests that smokers and subjects with chronic obstructive pulmonary disease (COPD) have neutrophilic inflammation in peripheral airways. The aim of this study was to examine whether current smokers have higher lung tissue uptake of F-18-FDG than never-smokers when correcting for air fraction of the lungs. Methods We prospectively recruited 33 current smokers and 33 never-smokers among subjects referred for diagnosis or staging of cancer, other than lung cancer, with combined positron emission tomography/computed tomography (PET/CT) with F-18-FDG. Subjects with focal F-18-FDG uptake or focal CT abnormalities in the lungs were excluded. The lungs were segmented in the CT image, and lung density measured. F-18-FDG uptake was measured in the corresponding volume and corrected for air fraction. Results Lung uptake of F-18-FDG, corrected for air fraction, was 12 center dot 5 and 8 per cent higher in the right and left lungs, respectively, in current smokers than in never-smokers (P<0 center dot 05). Conclusion Abnormal lung tissue uptake of F-18-FDG may be masked by reduced lung density if the uptake is not related to air fraction. Increased uptake of F-18-FDG in lung tissue in current smokers relative to never-smokers may reflect inflammation in peripheral airways. Measurements of F-18-FDG uptake in the lung tissue may be useful for animal and human studies of airways disease in COPD and the relation between airway and systemic inflammation.
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| 17. |
- Geborek, Pierre, et al.
(författare)
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Measurement of oxygen and carbon dioxide partial pressures in synovial fluid after tonometry
- 1988
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Ingår i: Clinical Physiology. - 1365-2281. ; 8:4, s. 427-432
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Tidskriftsartikel (refereegranskat)abstract
- A commercially available gas analyser was used to measure tension of oxygen (PO2) and carbon dioxide (PCO2) in synovial fluid samples after tonometry. Measured values of PCO2 were close to the expected (median difference 0.2 kPa, range -0.4 to 0.4) within the analysed concentration range of 4-10 kPa. No consistent difference between measured and expected values of PO2 were found for oxygen in the range 3-11 kPa (median difference 0.1 kPa, range -0.3 to 1.2). For oxygen tensions below 3 kPa, however, the measured values invariably overestimated the actual PO2, the errors ranging from 0.3 to 1.9 kPa, median 1.1. The importance of proper handling of samples was investigated and storage for 1 h at 0 degrees C in plastic syringes resulted in elevation of the PO2 levels measured (range of elevation 0.2 to 3.6 kPa, median 1.15), whilst no significant differences were found when stored in glass syringes. Within the limits stated, commercially available gas analysers may thus be used to investigate these parameters related to local tissue metabolism in effusive joint conditions.
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| 18. |
- Granqvist, P, et al.
(författare)
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Sensed presence and mystical experiences are predicted by suggestibility, not by the application of transcranial weak complex magnetic fields
- 2005
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Ingår i: Neuroscience Letters. - : Elsevier BV. - 0304-3940. ; 379:1, s. 1-6
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Tidskriftsartikel (refereegranskat)abstract
- Transcranial magnetic stimulation (TMS) with weak (micro Tesla) complex waveform fields have been claimed to evoke the sensed presence of a sentient being in up to 80% in the general population. These findings have had a questionable neurophysiological foundation as the fields are approximately six orders of magnitude weaker than ordinary TMS fields. Also, no independent replication has been reported. To replicate and extend previous findings, we performed a double-blind experiment (N = 89), with a sham-field control group. Personality characteristics indicating suggestibility (absorption, signs of abnormal temporal lobe activity, and a "new age"-life-style orientation) were used as predictors. Sensed presence, mystical, and other somatosensory experiences previously reported from the magnetic field stimulation were outcome measures. We found no evidence for any effects of the magnetic fields, neither in the entire group, nor in individuals high in suggestibility. Because the personality characteristics significantly predicted outcomes, suggestibility may account for previously reported effects. Our results strongly question the earlier claims of experiential effects of weak magnetic fields.
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| 19. |
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| 20. |
- Gutte, Henrik, et al.
(författare)
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Automated interpretation of PET/CT images in patients with lung cancer.
- 2007
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Ingår i: Nuclear Medicine Communications. - 1473-5628. ; 28:2, s. 79-84
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To develop a completely automated method based on image processing techniques and artificial neural networks for the interpretation of combined [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) and computed tomography (CT) images for the diagnosis and staging of lung cancer. Methods: A total of 87 patients who underwent PET/CT examinations due to suspected lung cancer comprised the training group. The test group consisted of PET/CT images from 49 patients suspected with lung cancer. The consensus interpretations by two experienced physicians were used as the 'gold standard' image interpretation. The training group was used in the development of the automated method. The image processing techniques included algorithms for segmentation of the lungs based on the CT images and detection of lesions in the PET images. Lung boundaries from the CT images were used for localization of lesions in the PET images in the feature extraction process. Eight features from each examination were used as inputs to artificial neural networks trained to classify the images. Thereafter, the performance of the network was evaluated in the test set. Results: The performance of the automated method measured as the area under the receiver operating characteristic curve, was 0.97 in the test group, with an accuracy of 92%. The sensitivity was 86% at a specificity of 100%. Conclusions: A completely automated method using artificial neural networks can be used to detect lung cancer with such a high accuracy that the application as a clinical decision support tool appears to have significant potential.
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| 21. |
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| 22. |
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| 23. |
- Ly, John, et al.
(författare)
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Semi-automatic analysis of standard uptake values in serial PET/CT studies in patients with lung cancer and lymphoma
- 2012
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Ingår i: BMC Medical Imaging. - : Springer Science and Business Media LLC. - 1471-2342. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Background: Changes in maximum standardised uptake values (SUVmax) between serial PET/CT studies are used to determine disease progression or regression in oncologic patients. To measure these changes manually can be time consuming in a clinical routine. A semi-automatic method for calculation of SUVmaxin serial PET/CT studies was developed and compared to a conventional manual method. The semi-automatic method first aligns the serial PET/CT studies based on the CT images. Thereafter, the reader selects an abnormal lesion in one of the PET studies. After this manual step, the program automatically detects the corresponding lesion in the other PET study, segments the two lesions and calculates the SUVmaxin both studies as well as the difference between the SUVmaxvalues. The results of the semi-automatic analysis were compared to that of a manual SUVmaxanalysis using a Philips PET/CT workstation. Three readers did the SUVmaxreadings in both methods. Sixteen patients with lung cancer or lymphoma who had undergone two PET/CT studies were included. There were a total of 26 lesions.Results: Linear regression analysis of changes in SUVmaxshow that intercepts and slopes are close to the line of identity for all readers (reader 1: intercept = 1.02, R2= 0.96; reader 2: intercept = 0.97, R2= 0.98; reader 3: intercept = 0.99, R2= 0.98). Manual and semi-automatic method agreed in all cases whether SUVmaxhad increased or decreased between the serial studies. The average time to measure SUVmaxchanges in two serial PET/CT examinations was four to five times longer for the manual method compared to the semi-automatic method for all readers (reader 1: 53.7 vs. 10.5 s; reader 2: 27.3 vs. 6.9 s; reader 3: 47.5 vs. 9.5 s; p < 0.001 for all).Conclusions: Good agreement was shown in assessment of SUVmaxchanges between manual and semi-automatic method. The semi-automatic analysis was four to five times faster to perform than the manual analysis. These findings show the feasibility of using semi-automatic methods for calculation of SUVmaxin clinical routine and encourage further development of programs using this type of methods. © 2012 Ly et al; licensee BioMed Central Ltd.
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| 24. |
- Mattsson, Tomas, et al.
(författare)
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Sympathetic Nerve Dysfunction is Common in Patients With Chronic Intestinal Pseudo-obstruction.
- 2008
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Ingår i: Journal of Clinical Gastroenterology. - : Ovid Technologies (Wolters Kluwer Health). - 1539-2031 .- 0192-0790. ; 42:2, s. 174-177
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Tidskriftsartikel (refereegranskat)abstract
- GOAL: To clarify whether disturbances in the autonomic nervous system, reflected in abnormal cardiovascular reflexes, could explain symptoms of impaired heat regulation in patients with intestinal pseudo-obstruction. BACKGROUND: Chronic intestinal pseudo-obstruction is a clinical syndrome characterized by diffuse, unspecific gastrointestinal symptoms due to damage to the enteric nervous system or the smooth muscle cells. These patients often complain of excessive sweating or feeling cold, suggesting disturbances in the autonomic nervous system. Earlier studies have pointed to a coexistence of autonomic disturbances in the enteric and cardiovascular nervous system. STUDY: Thirteen consecutive patients (age range 23 to 79, mean 44 y) fulfilling the criteria for chronic intestinal pseudo-obstruction were investigated. Six of them complained of sweating or a feeling of cold. Examination of autonomic reflexes included heart rate variation to deep-breathing (expiration/inspiration index), heart rate reaction to tilt (acceleration index, brake index), and vasoconstriction (VAC) due to indirect cooling by laser doppler (VAC-index; high index indicates impaired VAC). Test results in patients were compared with healthy individuals. RESULTS: Patients had significantly higher (more abnormal) median VAC-index compared with healthy controls [1.79 (interquartile ranges 1.89) vs. 0.08 (interquartile ranges 1.29); P=0.0007]. However, symptoms of impaired heat regulation were not related to the VAC-index. There were no differences in expiration/inspiration, acceleration index, or brake index between patients and controls. CONCLUSIONS: The patients with severe gastrointestinal dysmotility showed impaired sympathetic nerve function which, however, did not seem to be associated with symptoms of impaired heat regulation.
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| 25. |
- Metry, George, et al.
(författare)
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Effect of normalization of hematocrit on brain circulation and metabolism in hemodialysis patients
- 1999
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Ingår i: Journal of the American Society of Nephrology. - 1046-6673 .- 1533-3450. ; 10:4, s. 854-863
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Tidskriftsartikel (refereegranskat)abstract
- Full correction of anemia with recombinant human erythropoietin (rhEPO) has been reported to reduce the risk of cardiovascular morbidity and mortality and improve the quality of life in hemodialysis (HD) patients. Effects of normalization of hematocrit on cerebral blood flow and oxygen metabolism were investigated by positron emission tomography. Regional cerebral blood flow (rCBF), cerebral blood volume (rCBV), oxygen extraction ratio (rOER), and metabolic rate for oxygen (rCMRO2) were measured in seven HD patients before and after correction of anemia and compared with those in six healthy control subjects. In addition, blood rheology before and on rhEPO therapy was measured in HD patients, which included blood viscosity, plasma viscosity, erythrocyte fluidity, and erythrocyte aggregability. The results showed that plasma viscosity was high (1.51+/-0.19 mPa x s) and erythrocyte fluidity was low (85.8+/-4.8 Pa(-1) x s(-1)), while whole blood viscosity was within the normal range (3.72+/-0.38 mPa x s) before rhEPO therapy. After treatment, the hematocrit rose significantly from 29.3+/-3.3 to 42.4+/-2.2% (P<0.001), accompanied by a significant increase in the whole blood viscosity to 4.57+/-0.16 mPa x s, nonsignificant decrease in erythrocyte fluidity to 79.9+/-7.4 mPa(-1) x s(-1) and nonsignificant change in plasma viscosity (1.46+/-1.3 mPa x s). Positron emission tomography measurements revealed that by normalization of hematocrit, rCBF significantly decreased from 65+/-11 to 48+/-12 ml/min per 100 cm3 (P<0.05). However, arterial oxygen content (caO2) significantly increased from 5.7+/-0.7 to 8.0+/-0.4 mmol/L (P<0.0001), rOER of the hemispheres significantly increased from 44+/-3 to 51+/-6% (P<0.05) and became significantly higher than healthy control subjects (P<0.05). In addition, rCBV significantly increased from 3.5+/-0.5 to 4.6+/-0.6 ml/100 cc brain tissue. The results showed that oxygen supply to the brain tissue increased with normalization of hematocrit, but it was accompanied by increased oxygen extraction in the brain tissue. This may be assumed to be related to the decrease of erythrocyte velocity in the cerebral capillaries as a result of the decreased blood deformability and the increased plasma viscosity.
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