| 1. |
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| 2. |
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| 3. |
- Almquist, H, et al.
(författare)
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Performance of simultaneous emission-transmission systems for attenuation-corrected SPEct: a method for validation applied to two camera systems
- 2001
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Ingår i: Nuclear Medicine Communications. - 1473-5628. ; 22:7, s. 759-766
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Tidskriftsartikel (refereegranskat)abstract
- Several commercially available systems for attenuation correction in single photon emission computed tomography (SPECT) based on a transmission scan have been introduced that vary in performance. A test procedure for attenuation correction in SPECT is described and applied to two principally different gamma camera systems (the Siemens Multispect 3 triple-headed system [3HS] and the ADAC Genesys Vertex double-headed system [2HS]). The test procedure was based on geometrically well-defined phantoms. A torso phantom was used to illustrate the attenuation correction methods. The test procedure can be used without detailed knowledge of or access to the algorithms used for attenuation correction. The influence on the transmission measurement of radioactivity in a phantom was higher for the 2HS than for the 3HS. The 3HS produced satisfactory attenuation maps and corrected emission count rates to a constant value independent of phantom density and size. With the 2HS, there was a progressive decrease in the correction of emission count rates with increasing phantom density, and about 30% lower corrected count rates in the large compared with the small phantom. A decrease in measured attenuation coefficients in the vicinity of an emission source was demonstrated in large but not small phantoms. A likely explanation is erroneous correction of downscatter into the transmission energy window. This study demonstrates the need for independent evaluation of systems for attenuation correction in SPECT.
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| 4. |
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| 5. |
- Berglund, A Scott, et al.
(författare)
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Metaiodobenzylguanidine (MIBG) scintigraphy and computed tomography (CT) in clinical practice. Primary and secondary evaluation for localization of phaeochromocytomas
- 2001
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Ingår i: Journal of Internal Medicine. - : Wiley. - 1365-2796 .- 0954-6820. ; 249:3, s. 247-251
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To determine the diagnostic value of metaiodobenzylguanidine (MIBG) scintigraphy compared with computed tomography (CT) for the localization of phaeochromocytomas in clinical practice. DESIGN: Retrospective comparison between MIBG scintigrams and CT for localization of phaeochromocytomas in all patients successively examined with MIBG scintigraphy in Malmo from 1984 until January 1997. SETTING: Malmo University Hospital, Sweden. SUBJECTS: Sixty-four patients with clinically suspected phaeochromocytomas. MAIN OUTCOME MEASURES: MIBG scintigrams and CTs classified as positive or negative based on original interpretations (primary evaluation) and in a secondary evaluation by one blinded examiner are assessed through histological confirmation or clinical rule out of phaeochromocytomas. RESULTS: Twenty-five patients had surgically removed phaeochromocytomas. The remaining 39 patients had no proof of phaeochromocytomas. In the secondary evaluation, sensitivity for MIBG scintigraphy was 88% (22/25) and for CT was 100% (25/25). The specificity for MIBG scintigraphy was 89% (35/39) but only 50% for CT (18/36). Two out of a total of six extra-adrenal tumours were amongst the false-negative MIBG scintigrams. CONCLUSIONS: MIBG scintigraphy for the localization of phaeochromocytomas is superior to CT as far as specificity, whereas CT has a higher sensitivity. After biochemical diagnosis, CT will detect most phaeochromocytomas. MIBG scintigraphy can be of value in patients who show inconclusive results with biochemical testing and CT.
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| 6. |
- Bondesson, Eva, et al.
(författare)
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In vitro and in vivo aspects of quantifying intrapulmonary deposition of a dry powder radioaerosol.
- 2002
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Ingår i: International Journal of Pharmaceutics. - 1873-3476. ; 232:1-2, s. 149-156
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Tidskriftsartikel (refereegranskat)abstract
- Pulmonary delivery of pharmaceutical aerosols can be quantified using gamma scintigraphy. Technetium-99m, the most commonly used radionuclide in scintigraphic studies, cannot be incorporated into the drug molecule and, therefore, may be distributed differently from the drug itself, particularly if the drug is presented as a solid in a liquid suspension or as a dry powder formulation. This study demonstrated the importance of using conditions relevant to the in vivo situation in the in vitro characterisation of a dry powder aerosol of 99mTc-labelled lactose. The influence of inspiratory flow on the distribution of aerosol within the lungs was investigated in eight healthy subjects who inhaled the 99mTc-labelled lactose at four flows (30,40,60 and 80 l/min). No differences in penetration index (PI) or count density distribution of radioactivity were seen, indicating that regional distribution of aerosol in healthy airways was insensitive to differences in the inspiratory effort exerted by the subject while inhaling the experimental dry powder radioaerosol.
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| 7. |
- Bondesson, Eva, et al.
(författare)
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Planar gamma scintigraphy - points to consider when quantifying pulmonary dry powder aerosol deposition
- 2003
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Ingår i: International Journal of Pharmaceutics. - 1873-3476. ; 251:1-2, s. 33-47
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Tidskriftsartikel (refereegranskat)abstract
- Methodological aspects of planar gamma scintigraphy used to quantify pulmonary aerosol deposition were investigated using an experimental dry powder formulation. Particles of micronized salbutamol sulphate were labelled with technetium-99m and admixed to an ordered mixture of unlabelled micronized salbutamol sulphate and larger carrier particles of lactose. The radioaerosol was administered to 24 healthy subjects, 12 in each of two consecutive, similarly designed studies. Pulmonary deposition was determined using two methods: repeated planar imaging, and pharmacokinetic assessments following charcoal co-administration to prevent gastrointestinal salbutamol absorption. After due consideration had been taken to ensure appropriate radiolabelling, image acquisition and processing procedures, a scintigraphic estimate of 26.2% (24.2-28.4%) was obtained, which did not significantly differ from the pharmacokinetic estimate of 26.4% (24.4-28.7%). In summary, pre-study validation of the radiolabelling technique, quality control of radioaerosols produced during the study, correction for re-distribution of radiolabel from the lungs, selection of regions of interest, assessment of lung contours, correction for tissue attenuation of gamma rays and establishment of the actual recovery of radioactivity in the scintigraphic measurements could potentially affect the accuracy of the scintigraphic estimate of pulmonary deposition and, thus, should be carefully considered in the design or evaluation of any such study.
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| 8. |
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| 9. |
- Bornmyr, S, et al.
(författare)
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Effect of local cold provocation on systolic blood pressure and skin blood flow in the finger
- 2001
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Ingår i: Clinical Physiology. - : Wiley. - 1365-2281 .- 0144-5979. ; 21:5, s. 570-575
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Tidskriftsartikel (refereegranskat)abstract
- Demonstration of increased vascular cold reactivity in patients with Raynaud's syndrome is difficult. For medico-legal reasons, it is important to get objective measures of vasospasm in these patients. Evaluation of the degree of vasospasm also provides prognostic information which is useful for patient management. In this study, we compare two methods of arterial circulation measurement. The laser Doppler scanning is a new method, which uses the recently developed laser Doppler perfusion imaging (LDPI) instrument. The aim of the present study was to compare the effect on finger skin blood flow measured with LDPI with changes in finger systolic blood pressure during local cold provocation. The effect of such provocation, skin blood flow and systolic blood pressure, were studied in 15 healthy controls. Six patients with known traumatic vasospastic disease (TVD) were also tested with both methods. Finger skin blood flow was measured with LDPI on the distal phalanx of the index finger of the left hand, every minutes during 6 min of local heating at 40 degrees C followed by local cooling for 3 min at 15 degrees C and then for 3 min at 10 degrees C. Finger systolic blood pressure was measured with strain-gauge method before and after local cooling to 10 degrees C with a cuff perfused with water of desired temperature. The test was performed in the same finger within a week of the laser Doppler scanning. Local finger cooling to 15 degrees C and 10 degrees C caused a significant decrease in blood flow, most marked at 10 degrees C. There was, however, no correlation between the decrease in blood flow and blood pressure. In the TVD-patients decreases in skin blood flow were similar compared with the healthy controls. In contrast, the changes in systolic blood pressure, were outside normal range (systolic quotient <0.65) in five of the six patients (83%), and also in 11 of the 15 healthy controls (73%). In conclusion, there is no correlation between the decrease in finger skin blood flow and systolic blood pressure during local cold provocation. For diagnosis of traumatic vasospastic disease (TVD), local cold-induced changes in finger systolic blood pressure seems superior to changes in skin blood flow, but the ideal clinical method for demonstrating increased cold-induced vasospasm is, however, still lacking.
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| 10. |
- Brådvik, Ingela, et al.
(författare)
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Kinetics of lung clearance of 99mTc-DTPA in smoking patients with sarcoidosis compared to healthy smokers.
- 2002
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Ingår i: Respiratory Medicine. - : Elsevier BV. - 1532-3064 .- 0954-6111. ; 96:5, s. 317-321
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Tidskriftsartikel (refereegranskat)abstract
- Investigation of lung clearance of 99mTc-labelled diethylene triamine penta-acetic acid (DTPA) in smoking sarcoid patients has been impeded by difficulties to differ between pathology of clearance kinetics caused by sarcoidosis and by smoking. This study explores the kinetics of lung clearance of 99mTc-DTPA in 15 current smokers with intrathoracic sarcoidosis. The results are compared with findings from 16 healthy smokers. Measurements of lung clearance over 180 min, i.e. longer than usual, revealed in II of the sarcoid patients a bi-exponential lung clearance course, which is pathologic. All healthy smokers also showed a bi-exponential lung clearance. In the analysis of the bi-exponential curve an initial fast, and a slow clearance component could be separated. The smokers with sarcoidosis had a significantly higher elimination rate of the slow component than the healthy smokers. Thus, analysis of the late part of the lung clearance curve may be rewarding in smoking sarcoid patients. The study shows that lung clearance of 99mTc-DTPA may be a method useful also in smoking patients with sarcoidosis.
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| 11. |
- C-Bergstrand, Ingar, et al.
(författare)
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Timolol increased retrobulbar flow velocities in untreated glaucoma eyes but not in ocular hypertension
- 2001
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Ingår i: Acta Ophthalmologica Scandinavica. - : Wiley. - 1395-3907. ; 79:5, s. 455-461
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To investigate retrobulbar blood flow velocities and the effects of topical timolol treatment in eyes with newly detected, previously untreated open angle glaucoma or ocular hypertension. METHODS: Fifteen eyes with open angle glaucoma (OAG) and 12 eyes with ocular hypertension (OH), in the same number of patients, all untreated and newly detected, were examined with colour Doppler imaging of retrobulbar vessels before and after 1 month of topical timolol treatment (0.5% Timoptic BID). RESULTS: Baseline central retinal artery end diastolic velocity was lower (48%, p=0.0002) and resistive index higher (7.6%, p=0.018) in the OAG group than in the OH group. In the glaucoma group mean end diastolic velocity increased by 41%, (p=0.006) while resistive index decreased by 5.8%, (p=0.02) on treatment, while no significant changes were seen in the OH group. Blood flow velocities in the ophthalmic artery did not change with treatment. Baseline IOP and IOP reduction did not differ between OAG and OH group. CONCLUSION: Peripheral resistance to blood flow was found to be increased in untreated glaucoma eyes as compared to a similar group of eyes with ocular hypertension. Timolol treatment diminished resistance significantly in the glaucoma group, but not in the ocular hypertension group. Thus the two groups responded differently to timolol treatment. The reaction to IOP lowering treatment could indicate defective autoregulation in the glaucoma group.
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| 12. |
- Dahlback, M, et al.
(författare)
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Enhanced insulin absorption in the rabbit airways and lung by sodium dioctyl sulfosuccinate
- 2002
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Ingår i: Journal of Aerosol Medicine. - : Mary Ann Liebert Inc. - 0894-2684 .- 1557-9026. ; 15:1, s. 27-36
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this investigation was to study regional absorption of inhaled insulin together with an enhancer (sodium di-octyl-sulfosuccinate [DOSS]) in the rabbit airways and lung. Insulin was administered with or without DOSS by aerosol inhalation, intratracheal infusion, intranasally, sublingually, and without DOSS intravenously. Blood glucose and plasma levels of insulin were measured during 100 min from the start of administration. Inhalation of insulin (3 U) with 0.25% or 1% DOSS decreased average blood glucose levels significantly more than inhalation of insulin (3 U) without DOSS. Intratracheal administration of 1.5 U of insulin with 0.25% DOSS in 0.3 mL of vehicle decreased the average blood glucose level significantly compared with intratracheal administration of 1.5 U of insulin and no DOSS in 0.3 mL of vehicle and compared with 1.5 U of insulin with 0.25% DOSS in 0.15 mL of vehicle. Intravenous insulin (1.5 U) and inhaled (1.5 U) insulin in 0.25% DOSS decreased average blood glucose levels significantly compared with intratracheal (0.15 mL), intranasal, and sublingual administration of 1.5 U of insulin with 0.25% DOSS. The bioavailability of inhaled insulin (1.5 U) with 0.25% DOSS was estimated to be 16% in comparison with 7% for intratracheally (0.15 mL), 1% intranasally, and 0.8% sublingually administered insulin (1.5 U with 0.25% DOSS), respectively. Inhaled insulin together with the absorption enhancer DOSS decreased the blood glucose level more effectively than insulin given intratracheally, intranasally, or sublingually. The effect on blood glucose reflected the difference in plasma insulin concentration for the different routes of administration.
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| 13. |
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| 14. |
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| 15. |
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| 16. |
- Engström, Gunnar, et al.
(författare)
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Asymptomatic leg atherosclerosis is reduced by regular physical activity. Longitudinal results from the cohort "men born in 1914"
- 2001
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Ingår i: European Journal of Vascular and Endovascular Surgery. - : Elsevier BV. - 1532-2165 .- 1078-5884. ; 21:6, s. 502-507
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To study whether physical activity is associated with reduced occurrence of asymptomatic leg atherosclerosis. DESIGN: Longitudinal and cross-sectional analyses of the population-based cohort "men born in 1914". METHODS: Comparison of the systolic ankle/arm pressure index (AAI) at age 68 in groups who were sedentary, performed some activity, and performed regular physical training at 55 and 68 years of age. RESULTS: At 55 years of age, 100 (27%) were sedentary, 209 (58%) reported some physical activity and 54 (15%) reported regular physical training. At 68 years, 194 men (53%) reported the same degree of physical activity, 127 (35%) reported a higher physical activity, and 42 (12%) reported lower physical activity. Physical activity at 55 years (p =0.03) and increased physical activity between 55 and 68 years (p =0.03) were both associated with higher AAI at 68 after adjusting for potential confounders. At 68 years, AAI was 0.89+/-0.21, 1.01+/-0.13 and 1.05+/-0.11, respectively, in men who were sedentary, reported some physical activity, and regular physical training (p =0.0002). This association remained significant after adjustments for potential confounders. CONCLUSIONS: regular physical activity is associated with reduced occurrence of asymptomatic leg atherosclerosis, even in men taking up exercise after age of 55.
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| 17. |
- 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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| 18. |
- Engström, Gunnar, et al.
(författare)
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Lung function and cardiovascular risk: relationship with inflammation-sensitive plasma proteins.
- 2002
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Ingår i: Circulation. - 1524-4539. ; 106:20, s. 2555-2560
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Tidskriftsartikel (refereegranskat)abstract
- Background— The inverse relationship between pulmonary function and incidence of cardiovascular disease remains largely unexplained. This prospective study explored the hypothesis of a relationship with inflammation-sensitive plasma proteins. Methods and Results— Forced vital capacity (FVC) and plasma levels of fibrinogen, {alpha} 1-antitrypsin, haptoglobin, ceruloplasmin, and orosomucoid were determined in 5064 healthy men aged 28 to 61 years. All-cause mortality, cardiovascular mortality, and incidence of myocardial infarction were monitored over a mean follow-up period of 18.4 years. Low FVC (fourth quartile) was associated with higher protein levels and with increased incidences of myocardial infarction and cardiovascular death. Adjustments for protein levels reduced the age-adjusted relative risks (RRs) for myocardial infarction (from 1.99, 95% CI 1.5 to 2.6, to 1.70, 95% CI 1.3 to 2.2) and cardiovascular death (from 2.71, 95% CI 1.9 to 3.9, to 2.28, 95% CI 1.6 to 3.3) among men with low FVC, corresponding to {approx}25% of the excess risk. The risk factor–adjusted RRs were reduced from 1.45 (95% CI 1.1 to 1.9) to 1.38 (95% CI 1.1 to 1.8) and from 1.96 (95% CI 1.4 to 2.8) to 1.85 (95% CI 1.3 to 2.7) for myocardial infarction and cardiovascular death, respectively, corresponding to {approx}10% to 15% of the excess risk. Among men with low FVC, the risk factor–adjusted RR for myocardial infarction was 2.5 (95% CI 1.7 to 3.6) for those with high protein levels (>=2 proteins in top quartile) and 1.7 (95% CI 1.1 to 2.4) for those with low protein levels (<=1 protein in top quartile; reference, top quartile of FVC and low protein levels). Conclusions— FVC is significantly and inversely associated with plasma levels of inflammation-sensitive plasma proteins. This relationship contributes to but cannot fully explain the increased cardiovascular risk among men with low FVC.
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| 19. |
- Engström, Gunnar, et al.
(författare)
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Lung function, insulin resistance and incidence of cardiovascular disease: a longitudinal cohort study.
- 2003
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Ingår i: Journal of Internal Medicine. - : Wiley. - 1365-2796 .- 0954-6820. ; 253:5, s. 574-581
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Tidskriftsartikel (refereegranskat)abstract
- Objectives. To explore whether a reduced lung function is a risk factor for developing diabetes and insulin resistance (IR), and whether such relationship contributes to the largely unexplained association between lung function and incidence of cardiovascular disease (CVD). Design. Forced vital capacity (FVC) was assessed at baseline. Incidence of diabetes and IR [according to the homeostasis model assessment (HOMA) model] was assessed in a follow-up examination after 13.9 ± 2.6 and 9.4 ± 3.6 years for men and women, respectively. After the follow-up examination, incidence of CVD (stroke, myocardial infarction or cardiovascular death) was monitored over 7 years. Setting. Populations-based cohort study. Subjects. Initially nondiabetic men (n = 1436, mean age 44.6 years) and women (n = 896, mean age 49.8 years). Results. Prevalence of IR at the follow-up examination was 34, 26, 21 and 21%, respectively, for men in the first (lowest), second, third and fourth quartile of baseline FVC (P for trend <0.0001). The corresponding values for women were 30, 29, 25 and 17%, respectively (P for trend <0.001). Adjusted for potential confounders, the odds ratio (OR) for IR (per 10% increase in FVC) was 0.91 (CI: 0.84-0.99) for men and 0.89 (CI: 0.80-0.98) for women. FVC was similarly significantly associated with the incidence of diabetes (OR = 0.90, CI: 0.81-1.00), adjusted for sex and other confounders. The incidence of CVD after the follow-up examination was significantly increased only amongst subjects with low FVC who had developed IR (RR = 1.7, CI: 1.02-2.7). Conclusion. Subjects with a moderately reduced FVC have an increased risk of developing IR and diabetes. This relationship seems to contribute to the largely unexplained association between reduced lung function and incidence of CVD.
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| 20. |
- 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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| 21. |
- Ericsson, Anders, et al.
(författare)
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Automated interpretation of ventilation-perfusion lung scintigrams for the diagnosis of pulmonary embolism using support vector machines
- 2003
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Ingår i: 13th Scandinavian Conference, SCIA 2003 Halmstad, Sweden, June 29 – July 2, 2003 Proceedings/Lecture Notes in Computer Science. - 0302-9743 .- 1611-3349. - 9783540406013 ; 2749, s. 415-421
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Konferensbidrag (refereegranskat)abstract
- The purpose of this study was to develop a new completely automated method for the interpretation of ventilation-perfusion (V-P) lung scintigrams for the diagnosis of pulmonary embolism. A new way of extracting features, characteristic for pulmonary embolism is presented. These features are then used as input to a Support Vector Machine, which discriminates between pulmonary embolism or no embolism. Using a material of 509 training cases and 104 test cases, the performance of the system, measured as the area under the ROC curve, was 0.86 in the test group. It is concluded that a completely automatic method can be used for interpretation of V-P scintigrams. It is faster and more robust than a previously presented method [4,5] and the accuracy is at the same level as the the previous method. It also handles abnormalities in the lungs.
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| 22. |
- Evander, Eva, et al.
(författare)
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Role of ventilation scintigraphy in diagnosis of acute pulmonary embolism: an evaluation using artificial neural networks.
- 2003
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Ingår i: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089. ; 30:7, s. 961-965
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to assess the value of the ventilation study in the diagnosis of acute pulmonary embolism using a new automated method. Either perfusion scintigrams alone or two different combinations of ventilation/perfusion scintigrams were used as the only source of information regarding pulmonary embolism. A completely automated method based on computerised image processing and artificial neural networks was used for the interpretation. Three artificial neural networks were trained for the diagnosis of pulmonary embolism. Each network was trained with 18 automatically obtained features. Three different sets of features originating from three sets of scintigrams were used. One network was trained using features obtained from each set of perfusion scintigrams, including six projections. The second network was trained using features from each set of (joint) ventilation and perfusion studies in six projections. A third network was trained using features from the perfusion study in six projections combined with a single ventilation image from the posterior view. A total of 1,087 scintigrams from patients with suspected pulmonary embolism were used for network training. The test group consisted of 102 patients who had undergone both scintigraphy and pulmonary angiography. Performances in the test group were measured as area under the receiver operation characteristic curve. The performance of the neural network in interpreting perfusion scintigrams alone was 0.79 (95% confidence limits 0.71–0.86). When one ventilation image (posterior view) was added to the perfusion study, the performance was 0.84 (0.77–0.90). This increase was statistically significant (P=0.022). The performance increased to 0.87 (0.81–0.93) when all perfusion and ventilation images were used, and the increase in performance from 0.79 to 0.87 was also statistically significant (P=0.016). The automated method presented here for the interpretation of lung scintigrams shows a significant increase in performance when one or all ventilation images are added to the six perfusion images. Thus, the ventilation study has a significant role in the diagnosis of acute lung embolism.
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| 23. |
- Evilevitch, Vladimir, et al.
(författare)
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Microvascular response in guinea pig skin to histamine challenge with and without application of skin window.
- 2004
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961. ; 24:5, s. 266-269
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Tidskriftsartikel (refereegranskat)abstract
- We measured the microvascular response to histamine in guinea pig skin. Histamine (40 mg ml-1) was given either as a skin prick test or applied topically onto a skin window. The skin window was prepared by applying suction and gentle warming to the skin so that a blister was formed, and by removing the top of the blister. The microvascular response was measured as the accumulation of radiolabelled transferrin in the skin in vivo, reflecting a combination plasma exudation and vasodilatation. In the control (saline) challenge, the response was slightly greater in the skin window than after skin prick challenge and the scatter was larger. Histamine challenge resulted in a significant microvascular response with respect to the control situation when measured immediately after provocation for both challenge techniques. Ten minutes after challenge, a smaller response was measured, which was still significantly greater than control for the skin prick challenge, but not for topical provocation using the skin window technique. We conclude that the microvascular response to histamine after provocation with the skin prick technique is similar to that after topical provocation using the skin window technique. The skin window technique may have a lower sensitivity than the skin prick technique owing to a higher scatter in the control situation. This difference should be considered when performing and interpreting studies of the microvascular reaction in the skin.
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| 24. |
- Forsén, A, et al.
(författare)
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A 14-year prospective study of autonomic nerve function in Type 1 diabetic patients: association with nephropathy.
- 2004
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Ingår i: Diabetic Medicine. - : Wiley. - 1464-5491 .- 0742-3071. ; 21:8, s. 852-858
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Tidskriftsartikel (refereegranskat)abstract
- Aims Prospective studies of autonomic nerve function are rare. We have followed the progression of autonomic dysfunction in relation to nephropathy over 14 years in Type 1 diabetic patients. Methods Autonomic nerve function was assessed by heart-rate responses to deep breathing (E/I ratio) and tilting (acceleration and brake indices) and by the postural blood pressure reaction in 58 patients, 43 of whom were reassessed after 14 years. Nephropathy was evaluated by the degree of albuminuria (albuminuria > 20 µg/min or > 0.03 g/24 h) and glomerular filtration rate (51Cr-EDTA plasma clearance). The acceleration index had deteriorated after 7 years (P = 0.0155), whereas the E/I ratio (P = 0.0070) and the diastolic postural blood pressure reaction (P = 0.0054) had deteriorated 14 years after the baseline examination (age-corrected values). All those with albuminuria at the third examination showed signs of autonomic neuropathy at baseline (10 of 10) compared with only nine of 22 without (P = 0.0016). Multiple regression analysis showed that the association between autonomic dysfunction and future albuminuria was due to the E/I ratio. In addition, individuals with an abnormal postural diastolic blood pressure fall (n = 7) at baseline showed a greater fall in glomerular filtration rate more than others 7-14 years later [29 (16.5) ml/min/1.72 m2 vs. 11 (9) ml/min/1.72 m2; P = 0.0074]. Conclusion Autonomic nerve function had deteriorated after 14 years. Autonomic neuropathy and abnormal postural diastolic blood pressure falls at baseline were associated with future renal complications.
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