| 1. |
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| 2. |
- 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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| 3. |
- Danad, Ibrahim, et al.
(författare)
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Effect of cardiac hybrid O-15-water PET/CT imaging on downstream referral for invasive coronary angiography and revascularization rate
- 2014
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Ingår i: European Heart Journal Cardiovascular Imaging. - : Oxford University Press (OUP). - 2047-2404 .- 2047-2412. ; 15:2, s. 170-179
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Tidskriftsartikel (refereegranskat)abstract
- This study evaluates the impact of hybrid imaging on referral for invasive coronary angiography (ICA) and revascularization rates. A total of 375 patients underwent hybrid O-15-water positron emission tomography (PET)/computed tomography (CT)-based coronary angiography (CTCA) imaging for the evaluation of coronary artery disease (CAD). Downstream treatment strategy within a 60-day period after hybrid PET/CTCA imaging for ICA referral and revascularization was assessed. CTCA examinations were classified as showing no (obstructive) CAD, equivocal (borderline test result), or obstructive CAD, while the PET perfusion images were classified into normal or abnormal. On the basis of CTCA imaging, 182 (49) patients displayed no (obstructive) CAD. Only 10 (5) patients who showed no (obstructive) CAD on CTCA were referred for ICA, which were all negative. An equivocal CT study was observed in 80 (21) patients, among whom 56 (70) showed normal myocardial perfusion imaging (MPI), resulting in referral rates for ICA of 18 for normal MPI and 71 for abnormal MPI, respectively. No revascularizations were performed in the presence of normal MPI, while 59 of those with abnormal MPI were revascularized. CTCA indentified obstructive CAD in 113 (30) patients accompanied in 59 (52) patients with abnormal MPI. Referral rate for ICA was 57 for normal MPI and 88 for those with abnormal MPI, resulting in revascularization rates of 26 and 72, respectively. Hybrid O-15-water PET/CTCA imaging impacts clinical decision-making with regard to referral for ICA and revascularization procedures. Particularly, in the presence of an equivocal or abnormal CTCA, MPI could guide in the decision to refer for ICA and revascularization.
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| 4. |
- 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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| 5. |
- Danad, Ibrahim, et al.
(författare)
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Impact of anatomical and functional severity of coronary atherosclerotic plaques on the transmural perfusion gradient : a [O-15]H2O PET study
- 2014
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Ingår i: European Heart Journal. - : Oxford University Press (OUP). - 0195-668X .- 1522-9645. ; 35:31, s. 2094-U149
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Tidskriftsartikel (refereegranskat)abstract
- Background Myocardial ischaemia occurs principally in the subendocardial layer, whereas conventional myocardial perfusion imaging provides no information on the transmural myocardial blood flow (MBF) distribution. Subendocardial perfusion measurements and quantification of the transmural perfusion gradient (TPG) could be more sensitive and specific for the detection of coronary artery disease (CAD). The current study aimed to determine the impact of lesion severity as assessed by the fractional flow reserve (FFR) on subendocardial perfusion and the TPG using [O-15]H2O positron emission tomography (PET) imaging in patients evaluated for CAD. Methods and results Sixty-six patients with anginal chest pain were prospectively enrolled and underwent [O-15] H2O myocardial perfusion PET imaging. Subsequently, invasive coronary angiography was performed and FFR obtained in all coronary arteries irrespective of the PET imaging results. Thirty (45%) patients were diagnosed with significant CAD(i.e. FFR <= 0.80), whereas on a per vessel analysis (n = 198), 53 (27%) displayed a positive FFR. Transmural hyperaemic MBF decreased significantly from 3.09 +/- 1.16 to 1.67 +/- 0.57 mL min(-1) g(-1) (P < 0.001) in non-ischaemic and ischaemic myocardium, respectively. The TPG decreased during hyperaemia when compared with baseline (1.20 +/- 0.14 vs. 0.94 +/- 0.17, P < 0.001), and was lower in arteries with a positive FFR (0.97 +/- 0.16 vs. 0.88 +/- 0.18, P < 0.01). ATPG threshold of 0.94 yielded an accuracy to detect CAD of 59%, which was inferior to transmural MBF with an optimal cutoff of 2.20 mL min(-1) g(-1) and an accuracy of 85% (P < 0.001). Diagnostic accuracy of subendocardial perfusion measurements was comparable with transmural MBF (83 vs. 85%, respectively, P = NS). Conclusion Cardiac [O-15]H2O PET imaging is able to distinguish subendocardial from subepicardial perfusion in the myocardium of normal dimensions. Hyperaemic TPG is significantly lower in ischaemic myocardium. This technique can potentially be employed to study subendocardial perfusion impairment in more detail. However, the diagnostic accuracy of subendocardial hyperaemic perfusion and TPG appears to be limited compared with quantitative transmural MBF, warranting further study.
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| 6. |
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| 7. |
- Timmer, Stefan A J, et al.
(författare)
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Carriers of the hypertrophic cardiomyopathy MYBPC3 mutation are characterized by reduced myocardial efficiency in the absence of hypertrophy and microvascular dysfunction
- 2011
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Ingår i: European Journal of Heart Failure. - : Wiley. - 1388-9842 .- 1879-0844. ; 13:12, s. 1283-1289
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Tidskriftsartikel (refereegranskat)abstract
- AIMS:Next to left ventricular (LV) hypertrophy, hypertrophic cardiomyopathy (HCM) is characterized by microvascular dysfunction and reduced myocardial external efficiency (MEE). Insights into the presence of these abnormalities as early markers of disease are of clinical importance in risk stratification, and development of therapeutic approaches. Therefore, the aim was to investigate myocardial perfusion and energetics in genotype-positive, phenotype-negative HCM subjects (carriers).METHODS AND RESULTS:Fifteen carriers of an MYBPC3 mutation underwent [15O]water positron emission tomography (PET) to assess myocardial blood flow (MBF). [11C]acetate PET was performed to obtain myocardial oxygen consumption (MVO2). By use of cardiovascular magnetic resonance imaging, LV volumes and mass were defined to calculate MEE, i.e. the ratio between external work and MVO2. Eleven healthy, genotype-negative, family relatives underwent similar scanning protocols to serve as a control group. Left ventricular mass was comparable between carriers and controls (93 ± 25 vs. 99 ± 21 g, P= 0.85), as was MBF at rest (1.19 ± 0.34 vs. 1.18 ± 0.32 mL min−1 g−1, P= 0.92), and during hyperaemia (3.87 ± 0.75 vs. 3.96 ± 0.86 mL min−1 g−1, P= 0.77). Myocardial oxygen consumption averaged 0.137 ± 0.057 mL min−1 g−1 in carriers and was not significantly different from controls (0.125 ± 0.043 mL min−1 g−1, P= 0.29). Cardiac work, however, was slightly reduced in carriers (7398 ± 1384 vs. 9139 ± 2484 mmHg mL in controls, P= 0.08). As a consequence, MEE was significantly decreased in carriers (27 ± 10 vs. 36 ± 8% in controls, P= 0.02).CONCLUSION:Carriers display reduced myocardial work generation in relation to oxygen consumption, in the absence of hypertrophy and flow abnormalities. Hence, impaired myocardial energetics may constitute a primary component of HCM pathogenesis.
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| 8. |
- de Haan, Stefan, et al.
(författare)
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Parametric imaging of myocardial viability using ¹⁵O-labelled water and PET/CT : comparison with late gadolinium-enhanced CMR
- 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. ; 39:8, s. 1240-1245
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Tidskriftsartikel (refereegranskat)abstract
- PurposeThe perfusable tissue index (PTI) is a marker of myocardial viability. Recent technological advances have made it possible to generate parametric PTI images from a single [15O]H2O PET/CT scan. The purpose of this study was to validate these parametric PTI images.MethodsThe study population comprised 46 patients with documented or suspected coronary artery disease who were studied with [15O]H2O PET and late gadolinium-enhanced (LGE) cardiac magnetic resonance imaging (CMR).ResultsOf the 736 myocardial segments included, 364 showed some degree of LGE. PTI and perfusable tissue fraction (PTF) diminished with increasing LGE. The areas under the curve of the PTI and PTF, used to predict (near) transmural LGE on CMR, were 0.86 and 0.87, respectively. Optimal sensitivity and specificity were 91 % and 73 % for PTI and 69 % and 87 % for PTF, respectively.ConclusionPTI and PTF assessed with a single [15O]H2O scan can be utilized as markers of myocardial viability in patients with coronary artery disease.
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| 9. |
- Hofman, Mark B.M., et al.
(författare)
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In-vivo validation of interpolation-based phase offset correction in cardiovascular magnetic resonance flow quantification : A multi-vendor, multi-center study
- 2019
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Ingår i: Journal of Cardiovascular Magnetic Resonance. - : Springer Science and Business Media LLC. - 1097-6647 .- 1532-429X. ; 21:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: A velocity offset error in phase contrast cardiovascular magnetic resonance (CMR) imaging is a known problem in clinical assessment of flow volumes in vessels around the heart. Earlier studies have shown that this offset error is clinically relevant over different systems, and cannot be removed by protocol optimization. Correction methods using phantom measurements are time consuming, and assume reproducibility of the offsets which is not the case for all systems. An alternative previously published solution is to correct the in-vivo data in post-processing, interpolating the velocity offset from stationary tissue within the field-of-view. This study aims to validate this interpolation-based offset correction in-vivo in a multi-vendor, multi-center setup. Methods: Data from six 1.5 T CMR systems were evaluated, with two systems from each of the three main vendors. At each system aortic and main pulmonary artery 2D flow studies were acquired during routine clinical or research examinations, with an additional phantom measurement using identical acquisition parameters. To verify the phantom acquisition, a region-of-interest (ROI) at stationary tissue in the thorax wall was placed and compared between in-vivo and phantom measurements. Interpolation-based offset correction was performed on the in-vivo data, after manually excluding regions of spatial wraparound. Correction performance of different spatial orders of interpolation planes was evaluated. Results: A total of 126 flow measurements in 82 subjects were included. At the thorax wall the agreement between in-vivo and phantom was - 0.2 ± 0.6 cm/s. Twenty-eight studies were excluded because of a difference at the thorax wall exceeding 0.6 cm/s from the phantom scan, leaving 98. Before correction, the offset at the vessel as assessed in the phantom was - 0.4 ± 1.5 cm/s, which resulted in a - 5 ± 16% error in cardiac output. The optimal order of the interpolation correction plane was 1st order, except for one system at which a 2nd order plane was required. Application of the interpolation-based correction revealed a remaining offset velocity of 0.1 ± 0.5 cm/s and 0 ± 5% error in cardiac output. Conclusions: This study shows that interpolation-based offset correction reduces the offset with comparable efficacy as phantom measurement phase offset correction, without the time penalty imposed by phantom scans. Trial registration: The study was registered in The Netherlands National Trial Register (NTR) under TC 4865. Registered 19 September 2014. Retrospectively registered.
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| 10. |
- Rolf, Marijn P, et al.
(författare)
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Sequence optimization to reduce velocity offsets in cardiovascular magnetic resonance volume flow quantification - A multi-vendor study
- 2011
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Ingår i: JOURNAL OF CARDIOVASCULAR MAGNETIC RESONANCE. - : Taylor and Francis / BioMed Central. - 1097-6647. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Eddy current induced velocity offsets are of concern for accuracy in cardiovascular magnetic resonance (CMR) volume flow quantification. However, currently known theoretical aspects of eddy current behavior have not led to effective guidelines for the optimization of flow quantification sequences. This study is aimed at identifying correlations between protocol parameters and the resulting velocity error in clinical CMR flow measurements in a multi-vendor study. Methods: Nine 1.5T scanners of three different types/vendors were studied. Measurements were performed on a large stationary phantom. Starting from a clinical breath-hold flow protocol, several protocol parameters were varied. Acquisitions were made in three clinically relevant orientations. Additionally, a time delay between the bipolar gradient and read-out, asymmetric versus symmetric velocity encoding, and gradient amplitude and slew rate were studied in adapted sequences as exploratory measurements beyond the protocol. Image analysis determined the worst-case offset for a typical great-vessel flow measurement. Results: The results showed a great variation in offset behavior among scanners (standard deviation among samples of 0.3, 0.4, and 0.9 cm/s for the three different scanner types), even for small changes in the protocol. Considering the absolute values, none of the tested protocol settings consistently reduced the velocity offsets below the critical level of 0.6 cm/s neither for all three orientations nor for all three scanner types. Using multilevel linear model analysis, oblique aortic and pulmonary slices showed systematic higher offsets than the transverse aortic slices (oblique aortic 0.6 cm/s, and pulmonary 1.8 cm/s higher than transverse aortic). The exploratory measurements beyond the protocol yielded some new leads for further sequence development towards reduction of velocity offsets; however those protocols were not always compatible with the time-constraints of breath-hold imaging and flow-related artefacts. Conclusions: This study showed that with current systems there was no generic protocol which resulted into acceptable flow offset values. Protocol optimization would have to be performed on a per scanner and per protocol basis. Proper optimization might make accurate (transverse) aortic flow quantification possible for most scanners. Pulmonary flow quantification would still need further (offline) correction.
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| 11. |
- Schwitter, Juerg, et al.
(författare)
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MR-IMPACT : comparison of perfusion-cardiac magnetic resonance with single-photon emission computed tomography for the detection of coronary artery disease in a multicentre, multivendor, randomized trial
- 2008
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Ingår i: European Heart Journal. - : Oxford University Press (OUP). - 0195-668X .- 1522-9645. ; 29:4, s. 480-9
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: To determine in a multicentre, multivendor trial the diagnostic performance for perfusion-cardiac magnetic resonance (perfusion-CMR) in comparison with coronary X-ray angiography (CXA) and single-photon emission computed tomography (SPECT). METHODS AND RESULTS: Of 241 eligible patients from 18 centres, 234 were randomly dosed with 0.01, 0.025, 0.05, 0.075, or 0.1 mmol/kg Gd-DTPA-BMA (Omniscantrade mark, GE-Healthcare) per stress (0.42 mg/kg adenosine) and rest perfusion study. Coronary artery disease (CAD) was defined as diameter stenosis > or =50% on quantitative CXA. Five CMR and eight SPECT studies (of 225 complete studies) were excluded from analyses due to inadequate quality (three blinded readers scored per modality). The comparison of CMR vs. SPECT was based on receiver operating characteristic (ROC) analysis. Perfusion-CMR at the optimal CM dose (0.1 mmol/kg) had similar performance as SPECT, if only the SPECT studies of the 42 patients with this dose were considered [area under ROC curve (AUC): 0.86 +/- 0.06 vs. 0.75 +/- 0.09 for SPECT, P = 0.12]; however, diagnostic performance of perfusion-CMR was better vs. the entire SPECT population (AUC: 0.67 +/- 0.05, n = 212, P = 0.013). CONCLUSIONS: In this multicentre, multivendor trial, ROC analyses suggest perfusion-CMR as a valuable alternative to SPECT for CAD detection showing equal performance in the head-to-head comparison. Comparing perfusion-CMR with the entire SPECT population suggests CMR superiority over SPECT, which warrants further evaluation in larger trials.
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| 12. |
- Timmer, Stefan A J, et al.
(författare)
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Effects of alcohol septal ablation on coronary microvascular function and myocardial energetics in hypertrophic obstructive cardiomyopathy
- 2011
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Ingår i: American Journal of Physiology. Heart and Circulatory Physiology. - : American Physiological Society. - 0363-6135 .- 1522-1539. ; 301:1, s. H129-H137
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the effects of alcohol septal ablation (ASA) on microcirculatory function and myocardial energetics in patients with hypertrophic cardiomyopathy (HCM) and left ventricular outflow tract (LVOT) obstruction. In 15 HCM patients who underwent ASA, echocardiography was performed before and 6 mo after the procedure to assess the LVOT gradient (LVOTG). Additionally, [15O]water PET was performed to obtain resting myocardial blood flow (MBF) and coronary vasodilator reserve (CVR). Changes in LV mass (LVM) and volumes were assessed by cardiovascular magnetic resonance imaging. Myocardial oxygen consumption (MVVo2) was evaluated by [11C]acetate PET in a subset of seven patients to calculate myocardial external efficiency (MEE). After ASA, peak LVOTG decreased from 41 ± 32 to 23 ± 19 mmHg (P = 0.04), as well as LVM (215 ± 74 to 169 ± 63 g; P < 0.001). MBF remained unchanged (0.94 ± 0.23 to 0.98 ± 0.15 ml·min−1·g−1; P = 0.45), whereas CVR increased (2.55 ± 1.23 to 3.05 ± 1.24; P = 0.05). Preoperatively, the endo-to-epicardial MBF ratio was lower during hyperemia compared with rest (0.80 ± 0.18 vs. 1.18 ± 0.15; P < 0.001). After ASA, the endo-to-epicardial hyperemic (h)MBF ratio increased to 1.03 ± 0.26 (P = 0.02). ΔCVR was correlated to ΔLVOTG (r = −0.82; P < 0.001) and ΔLVM (r = −0.54; P = 0.04). MEE increased from 15 ± 6 to 20 ± 9% (P = 0.04). Coronary microvascular dysfunction in obstructive HCM is at least in part reversible by relief of LVOT obstruction. After ASA, hMBF and CVR increased predominantly in the subendocardium. The improvement in CVR was closely correlated to the absolute reduction in peak LVOTG, suggesting a pronounced effect of LV loading conditions on microvascular function of the subendocardium. Furthermore, ASA has favorable effects on myocardial energetics.
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| 13. |
- Timmer, Stefan A J, et al.
(författare)
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Reappraisal of a single-tissue compartment model for estimation of myocardial oxygen consumption by [11C]acetate PET : an alternative to conventional monoexponential curve fitting
- 2011
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Ingår i: Nuclear medicine communications. - 0143-3636 .- 1473-5628. ; 32:1, s. 59-62
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Tidskriftsartikel (refereegranskat)abstract
- Background:Myocardial washout kinetics of carbon-11 labelled acetate ([11C]acetate) by positron emission tomography (PET) closely correlate with myocardial oxygen consumption (MVO2). Analysis of the tissue time activity curve by conventional monoexponential curve fitting, however, does not account for spillover effects and recirculating 11C activity. In theory, a compartment model considering variations of the arterial input function and metabolic 11C contamination, could improve consistency of MVO2 estimations. The objective of the study was to investigate this hypothesis.Methods: Nineteen healthy volunteers were studied under resting conditions with [11C]acetate PET. Time activity curves were analysed by automated monoexponential curve fitting and a single-tissue compartment model to obtain Kmono and k2, as noninvasive indices of MVO2. Subsequently, Kmono and k2 were related to the rate-pressure product, as an indirect marker of MVO2.Results:The rate-pressure product was significantly correlated to Kmono (r=0.46, P=0.047) and k2 (r=0.75, P<0.001).Conclusion:The results of this study suggest that a single-tissue compartment model yields more accurate noninvasive estimates of MVO2 by the use of [11C]acetate PET in humans, in comparison with monoexponential curve fitting.
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| 14. |
- Timmer, Stefan A J, et al.
(författare)
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Relation of coronary microvascular dysfunction in hypertrophic cardiomyopathy to contractile dysfunction independent from myocardial injury
- 2011
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Ingår i: American Journal of Cardiology. - : Elsevier BV. - 0002-9149 .- 1879-1913. ; 107:10, s. 1522-1528
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Tidskriftsartikel (refereegranskat)abstract
- We studied the spatial relations among hyperemic myocardial blood flow (hMBF), contractile function, and morphologic tissue alterations in 19 patients with hypertrophic cardiomyopathy (HC). All patients were studied with oxygen-15 water positron emission tomography during rest and adenosine administration to assess myocardial perfusion. Cardiovascular magnetic resonance was performed to derive delayed contrast-enhanced images and to calculate contractile function (Ecc) with tissue tagging. Eleven healthy subjects underwent similar positron emission tomographic and cardiovascular magnetic resonance scanning protocols and served as a control group. In the HC group, hMBF averaged 2.46 ± 0.91 ml/min/g and mean Ecc was −14.7 ± 3.4%, which were decreased compared to the control group (3.97 ± 1.48 ml/min/g and −17.7 ± 3.2%, respectively, p <0.001 for the 2 comparisons). Delayed contrast enhancement (DCE) was present only in patients with HC, averaging 6.2 ± 10.3% of left ventricular mass. In the HC group, Ecc and DCE in the septum (−13.7 ± 3.6% and 10.2 ± 13.6%) significantly differed from the lateral wall (−16.0 ± 2.8% and 2.4 ± 5.9%, p <0.001 for the 2 comparisons). In general, hMBF and Ecc were decreased in segments displaying DCE compared to nonenhanced segments (p <0.001 for the comparisons). In the HC group, univariate analysis revealed relations of hMBF to Ecc (r = −0.45, p <0.001) and DCE (r = −0.31, p <0.001). Multivariate analysis revealed that Ecc was independently related to hMBF (beta −0.37, p <0.001) and DCE (beta 0.28, p <0.001). In conclusion, in HC hMBF is impaired and related to contractile function independent from presence of DCE. When present, DCE reflected a progressed disease state as characterized by an increased perfusion deficit and contractile dysfunction.
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| 15. |
- Timmer, S A J, et al.
(författare)
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Right ventricular energetics in patients with hypertrophic cardiomyopathy and the effect of alcohol septal ablation
- 2011
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Ingår i: Journal of Cardiac Failure. - : Elsevier BV. - 1071-9164 .- 1532-8414. ; 17:10, s. 827-831
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND:Diastolic dysfunction in hypertrophic cardiomyopathy (HCM) is accompanied by augmented left ventricular (LV) end-diastolic pressure, above all in the presence of LV outflow tract (LVOT) obstruction. Increased back-pressure may augment right ventricular (RV) afterload and induce an oxidative metabolic imbalance between the 2 ventricles. The aim was to study right-to-left ventricular oxidative metabolism in HCM and the effects of alcohol septal ablation (ASA).METHODS AND RESULTS:Twenty-one HCM patients were enrolled. Eleven healthy subjects served as a control group. Subjects underwent 2-dimensional echocardiography to assess LVOT gradient, left atrial size, and diastolic function. [11C]Acetate positron-emission tomography (PET) was performed to determine RVk2 and LVk2, as a noninvasive index of oxidative metabolism. Seven HCM patients with LVOT obstruction, scheduled to undergo ASA, were also studied 6 months after the procedure. RVk2 was higher in HCM patients than i control subjects (0.081 ± 0.021 min−1 vs. 0.061 ± 0.017 min−1; P = .05), whereas LVk2 was similar between groups. Consequently, RVk2/LVk2 was increased in the patients (0.85 ± 0.19 vs 0.59 ± 0.13; P = .004). In patients with obstructive HCM, ASA reduced RVk2 (0.085 ± 0.021 min−1 to 0.072 ± 0.022 min−1; P = .001). Inasmuch as LVk2 remained unaffected by the procedure, RVk2/LVk2 was decreased after ASA (0.66 ± 0.18; P = .03). The absolute change in LVOT gradient was related to the absolute change in RVk2 (r = 0.77; P = .044).CONCLUSIONS:In HCM patients, RV oxygen consumption is increased in relation to the LV. ASA reduces RV oxygen consumption in HCM patients with LVOT obstruction, suggesting that increased LV loading conditions and diastolic dysfunction play a predominant role in augmenting RV workload in these patients.
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| 16. |
- Vermeltfoort, Ilse A., et al.
(författare)
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Feasibility of subendocardial and subepicardial myocardial perfusion measurements in healthy normals with (15)O-labeled water and positron emission tomography
- 2011
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Ingår i: Journal of Nuclear Cardiology. - : Springer Science and Business Media LLC. - 1071-3581 .- 1532-6551. ; 18:4, s. 650-656
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Tidskriftsartikel (refereegranskat)abstract
- Positron emission tomography (PET) enables robust and reproducible measurements of myocardial blood flow (MBF). However, the relatively limited resolution of PET till recently prohibited distinction between the subendocardial and the subepicardial layers in non-hypertrophied myocardium. Recent developments in hard- and software, however, have enabled to identify a transmural gradient difference in animal experiments. The aim of this study is to determine the feasibility of subendocardial and subepicardial MBF in normal human hearts assessed with (15)O-labeled water PET. Twenty-seven healthy subjects (mean age 41 +/- A 13 years; 11 men) were studied with (15)O-labeled water PET to quantify resting and hyperaemic (adenosine) MBF at a subendocardial and subepicardial level. In addition, cardiac magnetic resonance imaging was performed to determine left ventricular (LV) volumes and function. Mean rest MBF was 1.46 +/- A 0.49 in the subendocardium, and 1.14 +/- A 0.342 mL center dot A min(-1) center dot A g(-1) in the subepicardium (P < .001). MBF during vasodilation was augmented to a greater extent at the subepicardial level (subendocardium vs subepicardium: 3.88 +/- A 0.86 vs 4.14 +/- A 0.88 mL center dot A min(-1) center dot A g(-1), P = .013). The endocardial-to-epicardial MBF ratio decreased significantly during hyperaemia (1.35 +/- A 0.23 to 1.12 +/- A 0.20, P < .001). Hyperaemic transmural MBF was inversely correlated with left ventricular end-diastolic volume index (LVEDVI) (r (2) = 0.41, P = .0003), with greater impact however at the subendocardial level. (15)O-labeled water PET enables MBF measurements with distinction of the subendocardial and subepicardial layers in the normal human heart and correlates with LVEDVI. This PET technique may prove useful in evaluating patients with signs of ischaemia due to coronary artery disease or microvascular dysfunction.
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