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- Johansson, Edvin, et al.
(författare)
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Gradient echo imaging of flowing hyperpolarized nuclei : theory and phantom studies on 129Xe dissolved in ethanol
- 2002
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Ingår i: Journal of Magnetic Resonance. - 1090-7807 .- 1096-0856. ; 159:1, s. 68-75
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Tidskriftsartikel (refereegranskat)abstract
- The influence of flip angle and flow velocity on the signal intensity achieved when imaging a hyperpolarized substance with a spoiled gradient echo sequence was investigated. The study was performed both theoretically and experimentally using hyperpolarized xenon dissolved in ethanol. Analytical expressions regarding the optimal flip angle with respect to signal and the corresponding signal level are presented and comparisons with thermally polarized substances are made. Both experimentally and theoretically, the optimal flip angle was found to increase with increasing flow velocity. Numerical calculations showed that the velocity dependence of the signal differs between the cases of hyperpolarized and thermally polarized substances.
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- Johansson, Edvin, et al.
(författare)
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Perfusion assessment with bolus differentiation : a technique applicable to hyperpolarized tracers
- 2004
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Ingår i: Magnetic Resonance in Medicine. - : Wiley. - 0740-3194 .- 1522-2594. ; 52:5, s. 51-1043
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Tidskriftsartikel (refereegranskat)abstract
- A new technique for assessing tissue blood flow using hyperpolarized tracers, based on the fact that the magnetization of a hyperpolarized substance can be destroyed permanently, is described. Assessments of blood flow with this technique are inherently insensitive to arterial delay and dispersion, and allow for quantification of the transit time and dispersion in the arteries that supply the investigated tissue. Renal cortical blood flow was studied in six rabbits using a 13C-labeled compound (2-hydroxyethylacrylate) that was polarized by the parahydrogen-induced polarization (PHIP) technique. The renal cortical blood flow was estimated to be 5.7/5.4 +/- 1.6/1.3 ml/min per milliliter of tissue (mean +/- SD, right/left kidney), and the mean transit time and dispersion in the renal arteries were determined to be 1.47/1.42 +/- 0.07/0.07 s and 1.78/1.93 +/- 0.40/0.42 s2, respectively.
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- Månsson, S, et al.
(författare)
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Echo-planar MR imaging of dissolved hyperpolarized 129Xe : Potential for MR angiography
- 2002
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Ingår i: Acta Radiologica. - : SAGE Publications. - 0284-1851 .- 1600-0455. ; 43:5, s. 60-455
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The feasibility of hyperpolarized 129Xe for fast MR angiography (MRA) was evaluated using the echo-planar imaging (EPI) technique.MATERIAL AND METHODS: Hyperpolarized Xe gas was dissolved in ethanol, a carrier agent with high solubility for Xe (Ostwald solubility coefficient 2.5) and long relaxation times. The dissolved Xe was injected as a bolus into a flow phantom where the mean flow velocity was 15 cm/s. Ultrafast EPI images with 44 ms scan time were acquired of the flowing bolus and the signal-to-noise ratios (SNR) were measured.RESULTS: The relaxation times of hyperpolarized Xe in ethanol were measured to T1=160+/-11 s and T2 approximately 20 s. The resulting images of the flowing liquid were of reasonable quality and had an SNR of about 70.CONCLUSION: Based on the SNR of the obtained Xe EPI images, it was estimated that rapid in vivo MRA with 129Xe may be feasible, provided that an efficient, biologically acceptable carrier for Xe can be found and polarization levels of more than 25% can be achieved in isotopically enriched 129Xe.
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- Månsson, Åsa, et al.
(författare)
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The quality of life in men after radical cystectomy with a continent cutaneous diversion or orthotopic bladder substitution: is there a difference?
- 2002
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Ingår i: BJU International. - 1464-4096. ; 90:4, s. 386-390
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Tidskriftsartikel (refereegranskat)abstract
- Objective To compare the quality of life (QoL) in men after radical cystectomy who had either a continent cutaneous diversion or orthotopic bladder substitution. Patients and methods Eighty men with at least 6 months of follow-up and with no signs of recurrent disease after radical cystectomy for bladder carcinoma, and who had either a continent cutaneous diversion or orthotopic bladder substitution, were sent two types of questionnaire, the Functional Assessment of Cancer Therapy-Bladder Cancer (FACT-Bl) and the Hospital Anxiety and Depression Scale (HADS), to determine their QoL. Results The FACT-Bl and HADS questionnaires were returned by 90% and 71% of the patients, respectively ( P < 0.05). In the replies to the generic version of FACT-Bl there were no differences between the groups in any domain, the scores being high in all. In questions covering intestinal, urinary and sexual items, patients with continent diversion had less trouble controlling urine (P< 0.0001), had to empty less often (P < 0.001), and had fewer symptoms when emptying (P < 0.05). Patients with neobladders had a better appreciation of appearance and better preserved erectile function (both P < 0.05). In the answers to the HADS, the mean scores were low (within the normal ranges) and did not differ between the groups. Conclusion Using two instruments tested for validity and reliability, there were no differences between patients with continent diversion and those with orthotopic substitution.
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- Andersson, Kerstin, et al.
(författare)
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Patients with insulin-dependent diabetes but not those with non-insulin-dependent diabetes have anti-sulfatide antibodies as determined with a new ELISA assay
- 2002
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Ingår i: Autoimmunity. - : Informa UK Limited. - 0891-6934 .- 1607-842X. ; 35:7, s. 463-8
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: In sera from newly diagnosed insulin-dependent diabetes mellitus patients (IDDM type 1) autoantibodies occur against different antigen determinants often shared with neural tissues. The role of these autoantibodies in the disease process is not yet clarified but they can be used as a diagnostic tool in the detection of IDDM patients. METHODS: We have analysed the occurrence of sulfatide autoantibodies in serum from patients with type 1 diabetes (n = 20), individuals with pre-type 1 diabetes (n = 6), patients with type 2 diabetes (n = 32) and controls (n = 43). The method used for the determination of the autoantibodies was a newly developed microtitre-ELISA assay utilizing a complex of sulfatide-albumin as the ligand. RESULTS: The new assay procedure for serum sulfatide autoantibodies showed good reproducibility. The total (day-to-day) imprecision based on analyses of three different serum samples with positive titres varied between 11 and 14% during an assay period of 6 months. None of the controls (0/43) had positive titres of sulfatide antibodies. Of the patients with type 1 diabetes, 85% displayed positive titres of anti-sulfatide antibodies while none of the type 2 patients did so. All individuals with pre-type 1 diabetes had positive titres of sulfatide antibodies. CONCLUSIONS: We conclude that sulfatide autoantibodies in serum can be reproducibly assayed by the newly developed microtitre-ELISA procedure. Elevated titres of sulfatide autoantibodies are a constant finding in newly diagnosed type 1 patients.
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- Balldin, J, et al.
(författare)
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A 6-month controlled naltrexone study: Combined effect with cognitive behavioral therapy in outpatient treatment of alcohol dependence
- 2003
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Ingår i: Alcoholism: Clinical and Experimental Research. - 0145-6008 .- 1530-0277. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Background: In several studies, patients with alcohol dependence treated with the opioid antagonist naltrexone have shown fewer relapses to heavy drinking than those receiving placebo. An interaction between the naltrexone effect and the type of psychological therapy has been observed. Methods: A 6-month, double-blind, placebo-controlled, parallel-group study was performed at 10 different investigation sites. After a placebo run-in period of 1 week, 118 patients were randomized into 4 treatment groups—50 mg of naltrexone daily or placebo in combination with either cognitive behavioral therapy (CBT) or supportive therapy. The CBT was performed over nine sessions according to the manual of Project MATCH (Matching Alcoholism Treatments to Client Heterogeneity). The supportive therapy was defined as "the treatment as usual." Alcohol consumption, craving, carbohydrate-deficient transferrin, medication compliance by tablet count, and adverse clinical events were assessed at all visits. Other liver enzymes and psychiatric symptoms were also determined. Results: Ninety-one (77%) patients completed the study, and 92 (78%) were 80% compliant with the medication regimen. A lower percentage of heavy-drinking days was shown in the naltrexone group (p = 0.045) compared with the placebo group, as was a lower craving score (p = 0.029). These results are supported by the lower levels of liver enzyme activities (p < 0.010 for aspartate aminotransferase, alanine aminotransferase, and γ-glutamyltransferase), but not by the carbohydrate-deficient transferrin levels, in the naltrexone group. The mean time period before the first day of heavy drinking was longer for the group treated with CBT (p = 0.010), especially in combination with naltrexone (p = 0.007). Naltrexone was well tolerated, and no patients discontinued the study due to side effects. Conclusions: This study supports the effect of naltrexone in outpatient treatment of alcohol dependence and suggests that a beneficial interaction effect with CBT can be expected.
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