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  • Diaz, Sandra, et al. (författare)
  • Hyperpolarized (3)He apparent diffusion coefficient MRI of the lung: Reproducibility and volume dependency in healthy volunteers and patients with emphysema.
  • 2008
  • Ingår i: Journal of Magnetic Resonance Imaging. - John Wiley and Sons Inc.. - 1522-2586. ; 27, s. 763-770
  • Tidskriftsartikel (refereegranskat)abstract
    • PURPOSE: To measure the apparent diffusion coefficient (ADC) of hyperpolarized (HP) (3)He gas using diffusion weighted MRI in healthy volunteers and patients with emphysema and examine the reproducibility and volume dependency. MATERIALS AND METHODS: A total of eight healthy volunteers and 16 patients with emphysema were examined after inhalation of HP (3)He gas mixed with nitrogen (N(2)) during breathhold starting from functional residual capacity (FRC) in supine position. Coronal diffusion-sensitized MR images were acquired. Each subject was imaged on three separate days over a seven-day period and received two different volumes (6% and 15% of total lung capacity [TLC]) of HP (3)He each day. ADC maps and histograms were calculated. The mean and standard deviation (SD) of the ADC at different days and volumes were compared. RESULTS: The reproducibility of the mean ADC and SD over several days was good in both healthy volunteers and patients (SD range of 0.003-0.013 cm(2)/second and 0.001-0.009 cm(2)/second at 6% and 15% of TLC for healthy volunteers, and a SD range of 0.001-0.041 cm(2)/second and 0.001-0.011 cm(2)/second, respectively, for patients). A minor but significant increase in mean ADC with increased inhaled gas volume was observed in both groups. CONCLUSION: Mean ADC and SD of HP (3)He MRI is reproducible and discriminates well between healthy controls and patients with emphysema at the higher gas volume. This method is robust and may be useful to gain new insights into the pathophysiology and course of emphysema. J. Magn. Reson. Imaging 2008. (c) 2008 Wiley-Liss, Inc.
  • Diaz, Sandra, et al. (författare)
  • Validity of apparent diffusion coefficient hyperpolarized He-3-MRI using MSCT and pulmonary function tests as references
  • 2009
  • Ingår i: European Journal of Radiology. - Elsevier. - 1872-7727. ; 71:2, s. 257-263
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose: To compare apparent diffusion coefficient (ADC) measurements from hyperpolarized (HP) helium (He-3)-magnetic resonance imaging (MRI) with quantitative data from multislice Computed Tomography (CT) (MSCT) of the whole lungs and pulmonary function tests (PFT). Materials and methods: Twenty-seven subjects, 22 with established emphysema and 5 with preclinical emphysema defined by PFT criteria, were examined with Hp He-3-MRI and MSCT. Mean age was 55 (+/- 12) years, 18 female and 9 male. Mean ADC from He-3-MRI was compared with emphysema index (EI), 15th percentile and mean lung density (MLD) values from MSCT. Both mean ADC and MSCT data were compared to PFT, especially percent of predicted diffusing capacity of carbon monoxide (%predicted DLCO), using Pearson's correlation test. Results: Mean ADC and standard deviation values were 0.392 +/- 0.119 cm(2)/s for the established emphysema group and 0.216 +/- 0.046 for the pre-clinical emphysema group. MSCT values for the established emphysema group and pre-clinical emphysema group were: EI (%) 11 +/- 12 and 0.4 +/- 0.6, respectively; 15th percentile (Hounsfield Units (HU)), -956 +/- 25 and -933 +/- 13, respectively and MLD (HU) -877 +/- 20 and -863 +/- 15, respectively. Correlations between mean ADC and El and 15th percentile were both r=0.90 and for MLD r=0.59. There was higher correlation between mean ADC and %predicted DLCO (r=0.90) than between El and %predicted DLCO (r=0.76). Conclusion: Hp He-3-MRI correlates well with density measurements from MSCT and agrees better than MSCT with %predicted DLCO which is the PFT most related to emphysema. (C) 2008 Elsevier Ireland Ltd. All rights reserved.
  • Alamidi, Daniel F, et al. (författare)
  • T1 Relaxation Time in Lungs of Asymptomatic Smokers.
  • 2016
  • Ingår i: PLoS ONE. - Public Library of Science. - 1932-6203. ; 11:3
  • Tidskriftsartikel (refereegranskat)abstract
    • Interest in using T1 as a potential MRI biomarker of chronic obstructive pulmonary disease (COPD) has recently increased. Since tobacco smoking is the major risk factor for development of COPD, the aim for this study was to examine whether tobacco smoking, pack-years (PY), influenced T1 of the lung parenchyma in asymptomatic current smokers.
  • Bernspang, Elisabeth, et al. (författare)
  • CT lung densitometry in young adults with alpha-1-antitrypsin deficiency
  • 2011
  • Ingår i: Respiratory Medicine. - Elsevier. - 1532-3064. ; 105:1, s. 74-79
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Severe (PiZZ) and moderate (PiSZ) alpha-1-antitrypsin (AAT) deficiency predispose to lung emphysema, especially in smokers. We hypothesized that multi-slice computed tomography (CT) might be superior to pulmonary function tests (PFT) to detect lung emphysema in AAT-deficient individuals at the age of 32 years. Methods: A subgroup of PiZZ and PiSZ individuals identified during the Swedish newborn screening programme in 1972-74 underwent multi-slice CT and PFT at the age of 32 years. From the CT scans the percentile density at 15% (PD15) and the relative area below -910 Hounsfield Units (RA(-910) HU) were calculated. The results of PFT and CT were compared between the AAT-deficient individuals and an age-matched control group. Results: Twenty-five PiZZ, 11 PiSZ and 17 PiMM individuals participated in the study. All Pi subgroups had normal lung function. The mean PD15 was 81 (SD 22) g/L in the PiZZ individuals, 96 (SD 35) g/L in the PiSZ individuals and 79 (SD 17) g/L in the PiMM individuals (ns), and the RA-910 were 30 (SD 18)%, 24 (SD 20)%, and 32 (SD 18)%, respectively (ns). For the never-smoker subgroups, in the PiZZ (n = 23), PiSZ (n = 8) and PiMM (n = 12), the mean PD15 were 95 (SD 35) g/L, 81 (SD 22) g/L, and 75 (SD 12) g/L, respectively (ns). PD15 was significantly correlated to CT derived lung size (r = -0.72; p < 0.001). Conclusions: CT densitometry revealed no signs of emphysema and no differences between the AAT-deficient individuals identified by neonatal screening and age-matched control subjects. (C) 2010 Elsevier Ltd. All rights reserved,
  • Johnson, Linda S B, et al. (författare)
  • ST segment depression on 24-hour electrocardiography predicts incident atrial fibrillation in two population-based cohorts
  • 2018
  • Ingår i: Europace. - Oxford University Press. - 1532-2092. ; 20:3, s. 429-434
  • Tidskriftsartikel (refereegranskat)abstract
    • Aims: ST-depression at 24hECG has not been studied in relation to atrial fibrillation (AF) risk. We aimed to determine whether ST-depression at 24hECG was associated with incident AF in two Swedish population-based cohorts - a sub-cohort of the Malmö Diet and Cancer study (MDCS), and the cohort 'Men born in 1914', and to determine whether 24hECG could be used to predict AF development.Methods and results: There were 378 acceptable 24hECG recordings in the MDCS (mean age 64.5 years, 43% men) and 394 acceptable recordings in 'Men born in 1914' (mean age 68.8 years). Incidence of AF was monitored using national registers of hospitalizations and outpatient visits in Sweden. Mean follow-up ± SD (cumulative incidence) was 10.4 ± 2 years (11.3%) in MDCS, and 10.9 ± 4 years (7.3%) in 'Men born in 1914'. ST-depressions were independently associated with incident AF; hazard ratio (HR) (95% CI) 2.41 (1.29-4.50, P = 0.006) and 2.28 (1.05-4.95, P = 0.038) after adjustment [age, sex, height, weight, systolic blood pressure, smoking, anti-hypertensive drugs, LDL/total cholesterol, and HOMA-IR (in MDCS)]. AF incidence was substantially lower in individuals who had neither ST-depressions or high supraventricular activity (SVA, negative predictive value 0.97 and 0.94, in MDCS and 'Men born in 1914', respectively), and similar in men and women.Conclusion: ST-depression at 24h-ECG is independently associated with incident AF, and incidence is substantially lower in individuals with neither ST-depression or high SVA. 24hECG can be used not only to diagnose AF but also to identify individuals at high and low AF risk.
  • Kindvall, Simon, et al. (författare)
  • The change of longitudinal relaxation rate in oxygen enhanced pulmonary MRI depends on age and BMI but not diffusing capacity of carbon monoxide in healthy never-smokers
  • 2017
  • Ingår i: PLoS ONE. - Public Library of Science. - 1932-6203. ; 12:5
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective: Oxygen enhanced pulmonary MRI is a promising modality for functional lung studies and has been applied to a wide range of pulmonary conditions. The purpose of this study was to characterize the oxygen enhancement effect in the lungs of healthy, never-smokers, in light of a previously established relationship between oxygen enhancement and diffusing capacity of carbon monoxide in the lung (DL,CO) in patients with lung disease. Methods: In 30 healthy never-smoking volunteers, an inversion recovery with gradient echo read-out (Snapshot-FLASH) was used to quantify the difference in longitudinal relaxation rate, while breathing air and 100% oxygen, ΔR1, at 1.5 Tesla. Measurements were performed under multiple tidal inspiration breath-holds. Results: In single parameter linear models, ΔR1 exhibit a significant correlation with age (p = 0.003) and BMI (p = 0.0004), but not DL,CO (p = 0.33). Stepwise linear regression of ΔR1 yields an optimized model including an age-BMI interaction term. Conclusion: In this healthy, never-smoking cohort, age and BMI are both predictors of the change in MRI longitudinal relaxation rate when breathing oxygen. However, DL,CO does not show a significant correlation with the oxygen enhancement. This is possibly because oxygen transfer in the lung is not diffusion limited at rest in healthy individuals. This work stresses the importance of using a physiological model to understand results from oxygen enhanced MRI.
  • Laura Aaltonen, H., et al. (författare)
  • Airspace Dimension Assessment with nanoparticles reflects lung density as quantified by MRI
  • 2018
  • Ingår i: International Journal of Nanomedicine. - Dove Medical Press Ltd.. - 1176-9114. ; 13, s. 2989-2995
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Airspace Dimension Assessment with inhaled nanoparticles is a novel method to determine distal airway morphology. This is the first empirical study using Airspace Dimension Assessment with nanoparticles (AiDA) to estimate distal airspace radius. The technology is relatively simple and potentially accessible in clinical outpatient settings. Method: Nineteen never-smoking volunteers performed nanoparticle inhalation tests at multiple breath-hold times, and the difference in nanoparticle concentration of inhaled and exhaled gas was measured. An exponential decay curve was fitted to the concentration of recovered nanoparticles, and airspace dimensions were assessed from the half-life of the decay. Pulmonary tissue density was measured using magnetic resonance imaging (MRI). Results: The distal airspace radius measured by AiDA correlated with lung tissue density as measured by MRI (ρ = -0.584; p = 0.0086). The linear intercept of the logarithm of the exponential decay curve correlated with forced expiratory volume in one second (FEV1) (ρ = 0.549; p = 0.0149). Conclusion: The AiDA method shows potential to be developed into a tool to assess conditions involving changes in distal airways, eg, emphysema. The intercept may reflect airway properties; this finding should be further investigated.
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