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- Thompson, Paul M., et al.
(författare)
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The ENIGMA Consortium : large-scale collaborative analyses of neuroimaging and genetic data
- 2014
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Ingår i: BRAIN IMAGING BEHAV. - : Springer Science and Business Media LLC. - 1931-7557 .- 1931-7565. ; 8:2, s. 153-182
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Tidskriftsartikel (refereegranskat)abstract
- The Enhancing NeuroImaging Genetics through Meta-Analysis (ENIGMA) Consortium is a collaborative network of researchers working together on a range of large-scale studies that integrate data from 70 institutions worldwide. Organized into Working Groups that tackle questions in neuroscience, genetics, and medicine, ENIGMA studies have analyzed neuroimaging data from over 12,826 subjects. In addition, data from 12,171 individuals were provided by the CHARGE consortium for replication of findings, in a total of 24,997 subjects. By meta-analyzing results from many sites, ENIGMA has detected factors that affect the brain that no individual site could detect on its own, and that require larger numbers of subjects than any individual neuroimaging study has currently collected. ENIGMA's first project was a genome-wide association study identifying common variants in the genome associated with hippocampal volume or intracranial volume. Continuing work is exploring genetic associations with subcortical volumes (ENIGMA2) and white matter microstructure (ENIGMA-DTI). Working groups also focus on understanding how schizophrenia, bipolar illness, major depression and attention deficit/hyperactivity disorder (ADHD) affect the brain. We review the current progress of the ENIGMA Consortium, along with challenges and unexpected discoveries made on the way.
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| 2. |
- de Langen, Adrianus J, et al.
(författare)
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Monitoring response to antiangiogenic therapy in non-small cell lung cancer using imaging markers derived from PET and dynamic contrast-enhanced MRI
- 2011
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Ingår i: Journal of Nuclear Medicine. - : Society of Nuclear Medicine. - 0161-5505 .- 1535-5667 .- 2159-662X. ; 52:1, s. 48-55
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Tidskriftsartikel (refereegranskat)abstract
- With antiangiogenic agents, tumor shrinkage may be absent, despite survival benefit. The present study assessed the predictive value of molecular imaging for the identification of survival benefit during antiangiogenic treatment with bevacizumab and erlotinib in patients with advanced non–small cell lung cancer.Methods:Patients were evaluated using an imaging protocol including CT, 18F-FDG PET, H215O PET, and dynamic contrast-enhanced MRI to derive measurements on tumor size, glucose metabolism, perfusion, and microvascular permeability. The percentage change in imaging parameters after 3 wk of treatment as compared with baseline was calculated and correlated with progression-free survival (PFS).Results:Forty-four patients were included, and 40 underwent CT and 18F-FDG PET at both time points. Complete datasets, containing all imaging modalities, were available for 14 patients. Bevacizumab and erlotinib treatment resulted in decreased metabolism, perfusion, and tumor size. A decrease in standardized uptake value or tumor perfusion of more than 20% at week 3 was associated with longer PFS (9.7 vs. 2.8 mo, P = 0.01, and 12.5 vs. 2.9 mo, P = 0.009, respectively). Whole-tumor Ktrans (the endothelial transfer constant) was not associated with PFS, but patients with an increase of more than 15% in the SD of tumor Ktrans values—that is, an increase in regions with low or high Ktrans values—after 3 wk had shorter PFS (2.3 vs. 7.0 mo, P = 0.008). A partial response, according to the response evaluation criteria in solid tumors (RECIST), at week 3 was also associated with prolonged PFS (4.6 vs. 2.9 mo, P = 0.017). However, 40% of patients with a partial response as their best RECIST response still had stable disease at week 3. In these cases tumor perfusion was already decreased and Ktrans heterogeneity showed no increase, indicating that the latter parameters seem to be more discriminative than RECIST at the 3-wk time point.Conclusion:PET and dynamic contrast-enhanced MRI were able to identify patients who benefit from bevacizumab and erlotinib treatment. Molecular imaging seems to allow earlier response evaluation than CT.
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| 3. |
- Danad, Ibrahim, et al.
(författare)
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Carotid artery intima-media thickness, but not coronary artery calcium, predicts coronary vascular resistance in patients evaluated for coronary artery disease
- 2012
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Ingår i: European Heart Journal: Cardiovascular Imaging. - : Oxford University Press (OUP). - 2047-2404 .- 2047-2412. ; 13:4, s. 317-323
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Tidskriftsartikel (refereegranskat)abstract
- Aims There is growing evidence that coronary artery disease (CAD) affects not only the conduit epicardial coronary arteries, but also the microvascular coronary bed. Moreover, coronary microvascular dysfunction (CMVD) often precedes the stage of clinically overt epicardial CAD. Coronary artery calcium (CAC) and carotid intima-media thickness (C-IMT) measured with computed tomography (CT) and ultrasound, respectively, are among the available techniques to non-invasively assess atherosclerotic burden. An increased CAC score and C-IMT have also been associated with CMVD. It is therefore of interest to explore and compare the potential of CAC against C-IMT to predict minimal coronary vascular resistance (CVR). Methods and results We evaluated 120 patients (mean age 56 +/- 9 years, 58 men) without a documented history of CAD in whom and results obstructive CAD was excluded. All patients underwent C-IMT measurements, CAC scoring, and vasodilator stress O-15-water positron emission tomography (PET)/CT, during which the coronary flow reserve (CFR) and minimal CVR were analysed. Minimal CVR increased significantly with increasing tertiles of C-IMT (22 +/- 6, 27 +/- 11, and 28 +/- 9 mmHg mL(-1) min(-1) g(-1), P < 0.01), whereas the CFR was comparable across all C-IMT groups (P = 0.50). Minimal CVR increased significantly with an increase in CAC score (23 +/- 9, 27 +/- 8, 32 +/- 10, and 32 +/- 7 mmHg mL(-1) min(-1) g(-1). P < 0.01), whereas the CFR did not show a significant decrease with higher CAC scores (P = 0.18). Multivariable regression analysis revealed that C-IMT (P = 0.03), but not CAC, was independently associated with minimal CVR. Conclusion C-IMT, but not CAC score, independently predicts minimal CVR in patients with multiple cardiovascular risk factors and suspected of CAD.
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| 4. |
- Danad, Ibrahim, et al.
(författare)
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Coronary risk factors and myocardial blood flow in patients evaluated for coronary artery disease : a quantitative [15O]H2O PET/CT study
- 2012
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Ingår i: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089. ; 39:1, s. 102-112
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundThere has been increasing interest in quantitative myocardial blood flow (MBF) imaging over the last years and it is expected to become a routinely used technique in clinical practice. Positron emission tomography (PET) using [15O]H2O is the established gold standard for quantification of MBF in vivo. A fundamental issue when performing quantitative MBF imaging is to define the limits of MBF in a clinically suitable population. The aims of the present study were to determine the limits of MBF and to determine the relationship among coronary artery disease (CAD) risk factors, gender and MBF in a predominantly symptomatic patient cohort without significant CAD.MethodsA total of 128 patients (mean age 54 ± 10 years, 50 men) with a low to intermediate pretest likelihood of CAD were referred for noninvasive evaluation of CAD using a hybrid PET/computed tomography (PET/CT) scanner. MBF was quantified with [15O]H2O at rest and during adenosine-induced hyperaemia. Obstructive CAD was excluded in these patients by means of invasive or CT-based coronary angiography.ResultsGlobal average baseline MBF values were 0.91 ± 0.34 and 1.09 ± 0.30 ml·min−1·g−1 (range 0.54–2.35 and 0.59–2.75 ml·min−1·g−1) in men and women, respectively (p < 0.01). However, no gender-dependent difference in baseline MBF was seen following correction for rate–pressure product (0.98 ± 0.45 and 1.09 ± 0.30 ml·min−1·g−1 in men and women, respectively; p = 0.08). Global average hyperaemic MBF values were 3.44 ± 1.20 ml·min−1·g−1 in the whole study population, and 2.90 ± 0.85 and 3.78 ± 1.27 ml·min−1·g−1 (range 1.52–5.22 and 1.72–8.15 ml·min−1·g−1) in men and women, respectively (p < 0.001). Multivariate analysis identified male gender, age and body mass index as having an independently negative impact on hyperaemic MBF.ConclusionGender, age and body mass index substantially influence reference values and should be corrected for when interpreting hyperaemic MBF values.
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