4 results on '"JANIER*, MARC F."'
Search Results
2. Tagged MRI and PET in severe CAD: discrepancy between preoperative inotropic reserve and intramyocardial functional outcome after revascularization.
- Author
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Mazzadi, Alejandro N., Janier, Marc F., Brossier, Benjamin, André-Fouët, Xavier, Revel, Didier, and Croisille, Pierre
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MAGNETIC resonance imaging , *POSITRON emission tomography , *DOBUTAMINE , *CORONARY disease , *CARDIOMYOPATHIES - Abstract
In severe coronary artery disease (CAD), it has been shown that intramyocardial inotropic reserve as assessed with tagged magnetic resonance imaging (MRI) is uniformly distributed among positron emission tomography (PET) patterns reflecting normal or concomitant reductions in perfusion and glucose metabolism. This preliminary study aimed to delineate the relationship between preoperative values of intramyocardial inotropic reserve (in different PET patterns of perfusion and glucose uptake) and intramyocardial functional outcome after surgical revascularization in severe CAD. Twelve patients underwent preoperative tagged MRI (baseline, 10 μg·kg-1·min-1 of dobutamine), H215O/[18F]fluoro-deoxyglucose PET imaging, and postoperative resting tagged MRI. Regional midmyocardial circumferential shortening (Ecc, in %) and PET patterns (normal, match viable, mismatch viable, and infarcted) were assessed in three tagged MRI/PET short-axis slices. Ecc at baseline ranged from 12 ± 6 to 8 ± 5 and 4 ± 4% in normal, match-viable, and infarcted regions, respectively (P < 0.05) and was 8 ± 5% in mismatch-viable regions. Of the 429 regions studied, 187 showed preoperative inotropic reserve with dobutamine, but 238 showed postoperative functional improvement. Postoperative functional improvement was less common in infarcted regions (41 vs. ∼60% in the other PET patterns), but the extent of improvement was similar among PET patterns (∼6%). Postoperative functional improvement occurred in 53% of all (normal, match viable, and mismatch viable) regions without inotropic reserve. In severe CAD, revascularization affords greater intramyocardial functional benefit than expected from the evaluation of intramyocardial inotropic reserve with low-dose dobutamine. Postoperative functional improvement in PET-viable regions without inotropic reserve suggests that factors other than regionally enhanced perfusion contribute to such functional improvement. [ABSTRACT FROM AUTHOR] more...
- Published
- 2004
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Catalog
3. Dobutamine-tagged MRI for inotropic reserve assessment in severe CAD: relationship with PET findings.
- Author
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Mazzadi, Alejandro N., Janier, Marc F., Brossier, Benjamin, André-Fouët, Xavier, McFadden, Eugene, Revel, Didier, and Croisille, Pierre
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MAGNETIC resonance imaging , *POSITRON emission tomography , *MYOCARDIAL reperfusion , *CORONARY disease , *DOBUTAMINE , *MYOCARDIUM - Abstract
The impact of blood flow reductions on the intramyocardial inotropic reserve has not yet been established in coronary artery disease (CAD). We therefore evaluated in severe CAD the relationship between positron emission tomography (PET) patterns of perfusion and glucose uptake and the corresponding tagged magnetic resonance imaging (tagged MRI) values of midmyocardial strains under low-dose dobutamine. Eighteen patients underwent tagged MRI (at rest with dobutamine) and H215O/18F fluorodeoxyglucose PET. Regional midmyocardial circumferential shortening (Ecc) and PET patterns (normal, match viable, mismatch viable, and infarcted) were assessed in three tagged MRI/PET short-axis slices. Regional Ecc at rest correlated with both perfusion (r = 0.49) and glucose uptake (r -= 0.58). The presence of the inotropic reserve was similar in normal, match viable, and infarcted (∼40% of regions vs. 52% in mismatch viable. P < 0.05), but die extent of the increase after dobutamine was lower in infarcted regions (P = 0.06). Within each PET pattern, regions were grouped according to their Ecc values at rest into three categories (high, intermediate, and low contractile performance). In mismatch viable (hibernation), the inotropic reserve was similar among the three categories, but in the other PET patterns the presence and extent of the inotropic reserve was higher in those regions with lowest Ecc– (without significant differences in perfusion). In severe CAD, the presence of die inotropic reserve assessed by midmyocardial changes under dobutamine does not relate to resting perfusion. At a similar level of perfusion, the presence of the inotropic reserve is inversely related to contractile performance at rest, but our results suggest that it may not be true for hibernating myocardium. [ABSTRACT FROM AUTHOR] more...
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- 2004
- Full Text
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4. Renal blood flow measurement by positron emission tomography using 15O-labeled water.
- Author
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Juillard, Laurent, Janier, Marc F., Fouque, Denis, Lionnet, Martine, Le Bars, Didier, Cinotti, Luc, Barthez, Paul, Gharib, Claude, Laville, Maurice, Juillard, L, Janier, M F, Fouque, D, Lionnet, M, Le Bars, D, Cinotti, L, Barthez, P, Gharib, C, and Laville, M more...
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RENAL circulation , *POSITRON emission tomography , *ANIMAL experimentation , *COMPARATIVE studies , *KIDNEYS , *LATEX , *RESEARCH methodology , *MEDICAL cooperation , *RADIOISOTOPES , *RESEARCH , *SWINE , *WATER , *EVALUATION research - Abstract
Background: Only few noninvasive methods have the potential to quantitate renal blood flow (RBF) in humans. Positron emission tomography (PET) is a clinical imaging method that can be used to measure the tissue blood flow noninvasively. The purpose of this study was to validate PET measurement of RBF using 15O-labeled water (H215O), a tracer that allows repeated measurements at short time intervals.Methods: RBF was measured in six pigs by PET and by radioactive microspheres (MS). Three measurements were performed in each pig at baseline (BL), during vascular expansion and dopamine infusion (DA; 20 microg. kg-1. min-1 intravenously), and during angiotensin II (Ang II) infusion (50 ng. kg-1. min-1 intravenously). RBF was estimated from aortic and renal tracer kinetics using a model adapted from the blood flow model described by Kety and Smith.Results: PET and MS values correlated strongly (y = 0.79x + 42, r = 0.93, P < 0.0001) over the RBF range from 100 to 500 mL. min-1. 100 g-1. Pharmacologically induced changes were significant and were measured equally well by PET and MS: 38 and 39%, respectively, below BL (P < 0.005 and P < 0.05) under Ang II, and 47 and 48%, respectively, above BL (P < 0.005 and P < 0.01) under DA. A Bland and Altman representation showed a low average difference of -17 +/- 45 mL. min-1. 100 g-1 (mean +/- SD).Conclusion: To our knowledge, this study provides the first validation of RBF measurement by PET using H215O over a large range of RBF values (100 to 500 mL. min-1. 100 g-1), which correspond to RBF values in both healthy subjects and in patients suffering from chronic renal failure. [ABSTRACT FROM AUTHOR] more...- Published
- 2000
- Full Text
- View/download PDF
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