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Träfflista för sökning "WFRF:(Knuuti Juhani) srt2:(2015-2019)"

Sökning: WFRF:(Knuuti Juhani) > (2015-2019)

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  • Grönman, Maria, et al. (författare)
  • Assessment of myocardial viability with [15O]water PET : A validation study in experimental myocardial infarction.
  • 2019
  • Ingår i: Journal of Nuclear Cardiology. - 1071-3581 .- 1532-6551.
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Assessment of myocardial viability is often needed in patients with chest pain and reduced ejection fraction. We evaluated the performance of reduced resting MBF, perfusable tissue fraction (PTF), and perfusable tissue index (PTI) in the assessment of myocardial viability in a pig model of myocardial infarction (MI).METHODS AND RESULTS: Pigs underwent resting [15O]water PET perfusion study 12 weeks after surgical (n = 16) or 2 weeks after catheter-based (n = 4) occlusion of the proximal left anterior descending coronary artery. MBF, PTF, and PTI were compared with volume fraction of MI in matched segments as assessed by triphenyl tetrazolium chloride staining of LV slices. MBF and PTF were lower in infarcted than non-infarcted segments. Segmental analysis of MBF showed similar area under the curve (AUC) of 0.85, 0.86, and 0.90 with relative MBF, PTF, and PTI for the detection of viable myocardium defined as infarct volume fraction of < 75%. Cut-off values of relative MBF of ≥ 67% and PTF of ≥ 66% resulted in accuracies of 90% and 81%, respectively.CONCLUSIONS: Our results indicate that resting MBF, PTF, and PTI based on [15O]water PET perfusion imaging are useful for the assessment of myocardial viability.
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  • Kudomi, Nobuyuki, et al. (författare)
  • Myocardial Blood Flow and Metabolic Rate of Oxygen Measurement in the Right and Left Ventricles at Rest and During Exercise Using 15O-Labeled Compounds and PET
  • 2019
  • Ingår i: ; 10
  • Tidskriftsartikel (refereegranskat)abstract
    • Aims: Simultaneous measurement of right (RV) and left ventricle (LV) myocardial blood flow (MBF), oxygen extraction fraction (OEF), and oxygen consumption (MVO2) non-invasively in humans would provide new possibilities to understand cardiac physiology and different patho-physiological states. Methods: We developed and tested an optimized novel method to measure MBF, OEF, and MVO2 simultaneously both in the RV and LV free wall (FW) using positron emission tomography in healthy young men at rest and during supine bicycle exercise. Results: Resting MBF was not significantly different between the three myocardial regions. Exercise increased MBF in the LVFW and septum, but MBF was lower in the RV compared to septum and LVFW during exercise. Resting OEF was similar between the three different myocardial regions (similar to 70%) and increased in response to exercise similarly in all regions. MVO2 increased approximately two to three times from rest to exercise in all myocardial regions, but was significantly lower in the RV during exercise as compared to septum LVFW. Conclusion: MBF, OEF, and MVO2 can be assessed simultaneously in the RV and LV myocardia at rest and during exercise. Although there are no major differences in the MBF and OEF between LV and RV myocardial regions in the resting myocardium, MVO2 per gram of myocardium appears to be lower the RV in the exercising healthy human heart due to lower mean blood flow. The presented method may provide valuable insights for the assessment of MBF, OEF and MVO2 in hearts in different pathophysiological states.
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  • Laaksonen, Marko, 1975-, et al. (författare)
  • Muscle free fatty-acid uptake associates to mechanical efficiency during exercise in humans
  • 2018
  • Ingår i: Frontiers in Physiology. - 1664-042X .- 1664-042X. ; 9:AUG
  • Tidskriftsartikel (refereegranskat)abstract
    • Intrinsic factors related to muscle metabolism may explain the differences in mechanical efficiency (ME) during exercise. Therefore, this study aimed to investigate the relationship between muscle metabolism and ME. Totally 17 healthy recreationally active male subjects were recruited and divided into efficient (EF; n=8) and inefficient (IE; n=9) groups, which were matched for age (mean±SD 24±2 vs. 23±2 yrs), BMI (23±1 vs. 23±2 kg m-2), physical acitivity levels (3.4±1.0 vs. 4.1±1.0 sessions/week), and V ̇O2peak (53±3 vs. 52±3 mL kg-1 min-1), respectively, but differed for ME at 45% of VO2peak intensity during submaximal bicycle ergometer test (EF 20.5±3.5 vs. IE 15.4±0.8 %, P < 0.001). Using Positron Emission Tomography, muscle blood flow (BF) and uptakes of oxygen (mVO2), fatty acids (FAU) and glucose (GU) were measured during dynamic submaximal knee-extension exercise. Workload-normalized BF (EF 35±14 vs. IE 34±11 mL 100g-1 min-1, P = 0.896), mVO2 (EF 4.1±1.2 vs. IE 3.9±1.2 mL 100g-1 min-1, P = 0.808), and GU (EF 3.1±1.8 vs. IE 2.6±2.3 μmol 100g-1 min-1, P = 0.641) as well as the delivery of oxygen, glucose, and fatty acids, as well as respiratory quotient were not different between the groups. However, FAU was significantly higher in EF than IE (3.1±1.7 vs. 1.7±0.6 μmol 100g-1 min-1, P < 0.047) and it also correlated with ME (r=0.56, P < 0.024) in the entire study group. EF group also demonstrated higher use of plasma fatty acids than IE, but no differences in use of plasma glucose and intramuscular energy sources were observed between the groups. These findings suggest that the effective use of plasma fatty acids is an important determinant of mechanical efficiency during exercise.
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  • Stuijfzand, Wijnand J, et al. (författare)
  • Relative flow reserve derived from quantitative perfusion imaging may not outperform stress myocardial blood flow for identification of hemodynamically significant coronary artery disease
  • 2015
  • Ingår i: Circulation Cardiovascular Imaging. - 1941-9651 .- 1942-0080. ; 8:1
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Quantitative myocardial perfusion imaging is increasingly used for the diagnosis of coronary artery disease. Quantitative perfusion imaging allows to noninvasively calculate fractional flow reserve (FFR). This so-called relative flow reserve (RFR) is defined as the ratio of hyperemic myocardial blood flow (MBF) in a stenotic area to hyperemic MBF in a normal perfused area. The aim of this study was to assess the value of RFR in the detection of significant coronary artery disease.METHODS AND RESULTS: From a clinical population of patients with suspected coronary artery disease who underwent oxygen-15-labeled water cardiac positron emission tomography and invasive coronary angiography, 92 patients with single- or 2-vessel disease were included. Intermediate lesions (diameter stenosis, 30%-90%; n=75) were interrogated by FFR. Thirty-eight (41%) vessels were deemed hemodynamically significant (>90% stenosis or FFR≤0.80). Hyperemic MBF, coronary flow reserve, and RFR were lower for vessels with a hemodynamically significant lesion (2.01±0.78 versus 2.90±1.16 mL·min(-1)·g(-1); P<0.001, 2.27±1.03 versus 3.10±1.29; P<0.001, and 0.67±0.23 versus 0.93±0.15; P<0.001, respectively). The correlation between RFR and FFR was moderate (r=0.54; P<0.01). Receiver operator characteristic curve analysis showed an area under the curve of 0.82 for RFR, which was not significantly higher compared with that for hyperemic MBF and coronary flow reserve (0.76; P=0.32 and 0.72; P=0.08, respectively).CONCLUSIONS: Noninvasive estimation of FFR by quantitative perfusion positron emission tomography by calculating RFR is feasible, yet only a trend toward a slight improvement of diagnostic accuracy compared with hyperemic MBF assessment was determined.
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7.
  • Trägårdh, Elin, et al. (författare)
  • Reporting nuclear cardiology: a joint position paper by the European Association of Nuclear Medicine (EANM) and the European Association of Cardiovascular Imaging (EACVI).
  • 2015
  • Ingår i: European Heart Journal-Cardiovascular Imaging. - : Oxford University Press. - 2047-2412. ; 16:3, s. 272-279
  • Tidskriftsartikel (refereegranskat)abstract
    • The report of an imaging procedure is a critical component of an examination, being the final and often the only communication from the interpreting physician to the referring or treating physician. Very limited evidence and few recommendations or guidelines on reporting imaging studies are available; therefore, an European position statement on how to report nuclear cardiology might be useful. The current paper combines the limited existing evidence with expert consensus, previously published recommendations as well as current clinical practices. For all the applications discussed in this paper (myocardial perfusion, viability, innervation, and function as acquired by single photon emission computed tomography and positron emission tomography or hybrid imaging), headings cover laboratory and patient demographics, clinical indication, tracer administration and image acquisition, findings, and conclusion of the report. The statement also discusses recommended terminology in nuclear cardiology, image display, and preliminary reports. It is hoped that this statement may lead to more attention to create well-written and standardized nuclear cardiology reports and eventually lead to improved clinical outcome.
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