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ABSTRACT: PURPOSE: To investigate the specific imaging findings of multidetector row CT (MDCT) and PET/CT with(18)F-FDG in cardiac dominant diffuse large B-cell lymphoma (DLBCL) in comparison with other cardiac tumours. METHODS: Five patients with DLBCL and 12 patients with other cardiac tumours including pericardial tumours were retrospectively reviewed. Among the patients with other cardiac tumours, seven had metastatic tumours, three had benign tumours, and two had other malignant cardiac tumours. The location of the cardiac mass, the encasement of the coronary artery surrounded by the mass, and pericardial effusion were evaluated using MDCT. The disease activity of the cardiac tumour was also evaluated by PET/CT. RESULTS: Four of the five DLBCL patients had primarily right-sided cardiac lesions, which was seen significantly more frequently in DLBCL than in other cardiac tumours (p = 0.028). All cardiac DLBCL lesions were located around the atrioventricular groove and encased the coronary arteries. ECG-gated cardiac MDCT showed that there was no apparent stenosis of the coronary arteries. Large amounts of pericardial effusion were seen in all DLBCL patients. PET/CT revealed significantly higher FDG uptake in DLBCL than in other cardiac malignant tumours, with no overlap (p = 0.0007). CONCLUSION: The combination of a right-sided cardiac mass with a large pericardial effusion and no apparent stenosis of the encased coronary artery revealed by MDCT and a high maximum standard uptake value were the specific findings in cardiac dominant DLBCL.
European Journal of Nuclear Medicine 05/2013; · 4.53 Impact Factor
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Journal of Nuclear Cardiology 04/2013; · 2.67 Impact Factor
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ABSTRACT: OBJECTIVE: Our objective was to evaluate the interrelation of atherosclerotic burden, as assessed by coronary artery calcium (CAC) score and coronary vascular function, as assessed by quantitative estimates of coronary flow reserve (CFR), with respect to prediction of clinical outcomes. BACKGROUND: The contribution of coronary vascular dysfunction, atherosclerotic burden, and the two combined to cardiac events is unknown. METHODS: A total of 901 consecutive patients undergoing 82-Rubidium myocardial perfusion imaging (MPI) PET and CAC scan. All patients had normal MPI. The primary endpoint was composite of major adverse cardiac events (MACE) including cardiac death, nonfatal myocardial infarction, late revascularization, and admission for heart failure. RESULTS: At baseline, CFR decreased (2.15±0.72, 2.02±0.65, and 1.88±0.64, P<0.0001) with increasing levels of CAC (0, 1-399, and ≥400). Over a median of 1.53 years (IQR: 0.77-2.44), there were 57 MACE. Annual risk-adjusted MACE rates were higher for patients with CFR <2.0 compared to ≥2.0 (1.9 vs. 5.5%/year, P=0.0007) but were only borderline associated with CAC (3.1, 3.4 and 6.2%/year for CAC of zero, 1-399, and ≥400, respectively; P=0.09). Annualized adjusted MACE was increased in the presence of impaired CFR even among patients with CAC=0 (1.4% vs. 5.2%, P=0.03). Cox proportional hazards analysis revealed that CFR improved model fit, risk discrimination and risk reclassification over clinical risk, whereas CAC only modestly improved model fit without improving risk discrimination or reclassification. CONCLUSION: In symptomatic patients with normal MPI, global CFR but not CAC provides significant incremental risk stratification over clinical risk score for prediction of major adverse cardiac events.
Journal of the American College of Cardiology 03/2013; · 14.16 Impact Factor
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Journal of Nuclear Cardiology 01/2013; · 2.67 Impact Factor
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ABSTRACT: We report the usefulness of F-FDG PET/CT for the detection and therapy evaluation of the infective vegetation. A 64-year-old man with history of aortic valve replacement presented with 2 months of fever without identifiable cause. Echocardiogram showed no inflammation vegetation or abnormality of mechanical valve function. FDG PET/CT with 50 IU/kg IV heparin revealed focal uptakes near the mechanical aortic valve. After antibiotics therapy, fever was ameliorated, and FDG PET/CT findings showed markedly decreased uptake of the lesions. FDG PET/CT is a powerful tool to detect endocarditis even in patients with no anatomical abnormalities.
Clinical nuclear medicine 12/2012; 37(12):1184-5. · 3.92 Impact Factor
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Satoru Chiba, Masanao Naya,
Hiroyuki Iwano,
Keiichiro Yoshinaga,
Chietsugu Katoh,
Osamu Manabe,
Satoshi Yamada,
Satoru Wakasa,
Suguru Kubota,
Yoshiro Matsui,
Nagara Tamaki,
Hiroyuki Tsutsui
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ABSTRACT: PURPOSE: Diastolic function is impaired in patients with end-stage heart failure. Favorable structural changes by surgical ventricular reconstruction (SVR) are thought to improve diastolic function, however, previous studies reported the contradictory results. We hypothesized that cardiac oxidative metabolism and diastolic dysfunction might improve in parallel to the reduction of left ventricular chamber size after SVR. METHODS: We studied 11 patients underwent SVR associated with mitral valve repair for end-stage heart failure due to dilated cardiomyopathy. Diastolic function was assessed by echocardiography and myocardial oxidative metabolism was measured by the monoexponential clearance (k-mono) of (11)C-acetate positron emission tomography at baseline and 1 month after SVR. RESULTS: All patients had preoperative severe diastolic dysfunction [E/A 4.11 ± 1.18, deceleration time (DT) 134 ± 26 ms]. The study patients were divided into 2 groups according to the changes in diastolic function after SVR; unchanged or worsened diastolic function in 6 patients (55 %, Non-responder) and improved diastolic function in 5 (45 %, Responder). K-mono and wall stress decreased only in responder. The changes in k-mono before and after SVR correlated with those in deceleration time (r = -0.63; p < 0.05) and wall stress (r = 0.75; p < 0.01). CONCLUSIONS: Improvement of diastolic dysfunction in patients with end-stage heart failure by SVR was in parallel to that in oxidative metabolism. It suggests that SVR reduced excessive metabolism during the diastolic phase, in part, via the improvement in diastolic function and the reduction in LV wall stress.
European Journal of Nuclear Medicine 11/2012; · 4.53 Impact Factor
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ABSTRACT: This study sought to evaluate whether impaired vasodilator function, an early manifestation of coronary artery disease, which precedes angiographic stenosis, accounts for increased risk among patients with moderate to severe renal dysfunction.
Patients with renal dysfunction are at increased risk of adverse cardiac outcomes, even in the absence of overt myocardial ischemia or infarction.
We included 866 consecutive patients with moderate to severe renal dysfunction referred for rest and stress myocardial perfusion positron emission tomography and followed them for a median of 1.28 years (interquartile range: 0.64 to 2.34). Regional myocardial perfusion abnormalities were assessed by semiquantitative visual analysis of positron emission tomography images. Rest and stress myocardial blood flow were calculated using factor analysis and a 2-compartment kinetic model; they were also used to compute coronary flow reserve (stress/rest myocardial blood flow). The primary endpoint was cardiac death.
Overall, 3-year cardiac mortality was 16.2%. After adjusting for clinical risk, left ventricular ejection fraction, as well as the magnitude of scar and/or ischemia, coronary flow reserve below the median (<1.5) was associated with a 2.1-fold increase in the risk of cardiac death (95% confidence interval [CI]: 1.3 to 3.5, p = 0.004). Incorporation of coronary flow reserve into cardiac death risk assessment models resulted in an increase in the C-index from 0.75 to 0.77 (p = 0.05) and in a net reclassification improvement of 0.142 (95% CI: 0.076 to 0.219). Among patients at intermediate risk based on all data other than coronary flow reserve, the net reclassification improvement was 0.489 (95% CI: 0.192 to 0.836). Corresponding improvements in risk assessment for mortality from any cause were also demonstrated.
The presence of coronary vascular dysfunction in patients with moderate to severe renal dysfunction, as assessed by positron emission tomography, is a powerful, independent predictor of cardiac mortality and provides meaningful incremental risk stratification over conventional markers of clinical risk.
JACC. Cardiovascular imaging 10/2012; 5(10):1025-34. · 14.29 Impact Factor
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ABSTRACT: Diabetes mellitus increases the risk of adverse cardiac outcomes and is considered a coronary artery disease (CAD) equivalent. We examined whether coronary vascular dysfunction, an early manifestation of CAD, accounts for increased risk among diabetics compared with nondiabetics.
A total of 2783 consecutive patients (1172 diabetics and 1611 nondiabetics) underwent quantification of coronary flow reserve (CFR; CFR=stress divided by rest myocardial blood flow) by positron emission tomography and were followed up for a median of 1.4 years (quartile 1-3, 0.7-3.2 years). The primary end point was cardiac death. Impaired CFR (below the median) was associated with an adjusted 3.2- and 4.9-fold increase in the rate of cardiac death for diabetics and nondiabetics, respectively (P=0.0004). Addition of CFR to clinical and imaging risk models improved risk discrimination for both diabetics and nondiabetics (c index, 0.77-0.79, P=0.04; 0.82-0.85, P=0.03, respectively). Diabetic patients without known CAD with impaired CFR experienced a rate of cardiac death comparable to that for nondiabetic patients with known CAD (2.8%/y versus 2.0%/y; P=0.33). Conversely, diabetics without known CAD and preserved CFR had very low annualized cardiac mortality, which was similar to patients without known CAD or diabetes mellitus and normal stress perfusion and systolic function (0.3%/y versus 0.5%/y; P=0.65).
Coronary vasodilator dysfunction is a powerful, independent correlate of cardiac mortality among both diabetics and nondiabetics and provides meaningful incremental risk stratification. Among diabetic patients without CAD, those with impaired CFR have event rates comparable to those of patients with prior CAD, whereas those with preserved CFR have event rates comparable to those of nondiabetics.
Circulation 08/2012; 126(15):1858-68. · 14.74 Impact Factor
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Chietsugu Katoh,
Keiichiro Yoshinaga,
Ran Klein,
Katsuhiko Kasai,
Yuuki Tomiyama,
Osamu Manabe, Masanao Naya,
Mamoru Sakakibara,
Hiroyuki Tsutsui,
Robert A deKemp,
Nagara Tamaki
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ABSTRACT: Myocardial blood flow (MBF) estimation with (82)Rubidium ((82)Rb) positron emission tomography (PET) is technically difficult because of the high spillover between regions of interest, especially due to the long positron range. We sought to develop a new algorithm to reduce the spillover in image-derived blood activity curves, using non-uniform weighted least-squares fitting.
Fourteen volunteers underwent imaging with both 3-dimensional (3D) (82)Rb and (15)O-water PET at rest and during pharmacological stress. Whole left ventricular (LV) (82)Rb MBF was estimated using a one-compartment model, including a myocardium-to-blood spillover correction to estimate the corresponding blood input function Ca(t)(whole). Regional K1 values were calculated using this uniform global input function, which simplifies equations and enables robust estimation of MBF. To assess the robustness of the modified algorithm, inter-operator repeatability of 3D (82)Rb MBF was compared with a previously established method.
Whole LV correlation of (82)Rb MBF with (15)O-water MBF was better (P < .01) with the modified spillover correction method (r = 0.92 vs r = 0.60). The modified method also yielded significantly improved inter-operator repeatability of regional MBF quantification (r = 0.89) versus the established method (r = 0.82) (P < .01).
A uniform global input function can suppress LV spillover into the image-derived blood input function, resulting in improved precision for MBF quantification with 3D (82)Rb PET.
Journal of Nuclear Cardiology 04/2012; 19(4):763-74. · 2.67 Impact Factor
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Journal of the American College of Cardiology 04/2012; 59(15):1408. · 14.16 Impact Factor
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Venkatesh L Murthy, Masanao Naya,
Courtney R Foster,
Jon Hainer,
Mariya Gaber,
Gilda Di Carli,
Ron Blankstein,
Sharmila Dorbala,
Arkadiusz Sitek,
Michael J Pencina,
Marcelo F Di Carli
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ABSTRACT: Impaired vasodilator function is an early manifestation of coronary artery disease and may precede angiographic stenosis. It is unknown whether noninvasive assessment of coronary vasodilator function in patients with suspected or known coronary artery disease carries incremental prognostic significance.
A total of 2783 consecutive patients referred for rest/stress positron emission tomography were followed up for a median of 1.4 years (interquartile range, 0.7-3.2 years). The extent and severity of perfusion abnormalities were quantified by visual evaluation of myocardial perfusion images. Rest and stress myocardial blood flows were calculated with factor analysis and a 2-compartment kinetic model and were used to compute coronary flow reserve (coronary flow reserve equals stress divided by rest myocardial blood flow). The primary end point was cardiac death. Overall 3-year cardiac mortality was 8.0%. The lowest tertile of coronary flow reserve (<1.5) was associated with a 5.6-fold increase in the risk of cardiac death (95% confidence interval, 2.5-12.4; P<0.0001) compared with the highest tertile. Incorporation of coronary flow reserve into cardiac death risk assessment models resulted in an increase in the c index from 0.82 (95% confidence interval, 0.78-0.86) to 0.84 (95% confidence interval, 0.80-0.87; P=0.02) and in a net reclassification improvement of 0.098 (95% confidence interval, 0.025-0.180). Addition of coronary flow reserve resulted in correct reclassification of 34.8% of intermediate-risk patients (net reclassification improvement=0.487; 95% confidence interval, 0.262-0.731). Corresponding improvements in risk assessment for mortality from any cause were also demonstrated.
Noninvasive quantitative assessment of coronary vasodilator function with positron emission tomography is a powerful, independent predictor of cardiac mortality in patients with known or suspected coronary artery disease and provides meaningful incremental risk stratification over clinical and gated myocardial perfusion imaging variables.
Circulation 11/2011; 124(20):2215-24. · 14.74 Impact Factor
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ABSTRACT: The purpose of this study was to quantify the effects of coronary atherosclerosis morphology and extent on myocardial flow reserve (MFR).
Although the relationship between coronary stenosis and myocardial perfusion is well established, little is known about the contribution of other anatomic descriptors of atherosclerosis burden to this relationship.
We evaluated the relationship between atherosclerosis plaque burden, morphology, and composition and regional MFR (MFR(regional)) in 73 consecutive patients undergoing Rubidium-82 positron emission tomography and coronary computed tomography angiography for the evaluation of known or suspected coronary artery disease.
Atherosclerosis was seen in 51 of 73 patients and in 107 of 209 assessable coronary arteries. On a per-vessel basis, the percentage diameter stenosis (p = 0.02) or summed stenosis score (p = 0.002), integrating stenoses in series, was the best predictor of MFR(regional). Importantly, MFR(regional) varied widely within each coronary stenosis category, even in vessels with nonobstructive plaques (n = 169), 38% of which had abnormal MFR(regional) (<2.0). Total plaque length, composition, and remodeling index were not associated with lower MFR. On a per-patient basis, the modified Duke CAD (coronary artery disease) index (p = 0.04) and the number of segments with mixed plaque (p = 0.01) were the best predictors of low MFR(global).
Computed tomography angiography descriptors of atherosclerosis had only a modest effect on downstream MFR. On a per-patient basis, the extent and severity of atherosclerosis as assessed by the modified Duke CAD index and the number of coronary segments with mixed plaque were associated with decreased MFR.
Journal of the American College of Cardiology 10/2011; 58(17):1807-16. · 14.16 Impact Factor
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ABSTRACT: Myocardial blood flow (MBF) can be measured with positron emission tomography (PET) and its quantification should provide diagnostic information beyond that obtained through standard visual analysis. However, this possibility has not been fully studied with PET and generator-produced rubidium-82 (⁸²Rb). We evaluated regional MBF in segments with and without ischemia using ⁸²Rb PET in patients with coronary artery disease (CAD).
Rest and stress ⁸²Rb PET and coronary angiography were performed for 12 patients with CAD. Based on angiography and relative ⁸²Rb perfusion images, segments were classified into 4 groups (Group A: myocardial ischemia with >70% diameter stenosis; Group B: no ischemia with stenosis; Group C: no ischemia without stenosis; Group D: ischemia without stenosis). Rest MBF was similar among the 4 groups. Groups A and B showed reduced hyperemic MBF compared with Group C (P < 0.05 vs. Group C) [Group A (n=16) 1.28 ± 0.58 ml·min⁻¹·g⁻¹; Group B (n=11) 1.72 ± 0.64 ml·min⁻¹·g⁻¹; Group C (n=9) 2.60 ± 1.09 ml·min⁻¹·g⁻¹; Group D (n=2) 2.33 ml·min⁻¹·g⁻¹]. Coronary flow reserves were inversely correlated with percent diameter stenosis (r=0.76, P < 0.0001).
Segments with ischemia and coronary stenosis had reduced hyperemic MBF. Segments with coronary stenosis without ischemia also had reduced hyperemic MBF compared with non-stenotic segments. MBF quantification using ⁸²Rb PET may provide additional diagnostic information.
Circulation Journal 08/2011; 75(11):2628-34. · 3.77 Impact Factor
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Takashi Sugiki, Masanao Naya,
Osamu Manabe,
Satoru Wakasa,
Suguru Kubota,
Satoru Chiba,
Hiroyuki Iwano,
Satoshi Yamada,
Keiichiro Yoshinaga,
Nagara Tamaki,
Hiroyuki Tsutsui,
Yoshiro Matsui
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ABSTRACT: The aim of this study was to investigate the effects of surgical ventricular reconstruction (SVR) on cardiac efficiency as a surrogate marker for cardiac function and oxidative metabolism in patients with severe heart failure.
Our new integrated overlapping left ventriculoplasty, modified SVR, combined with mitral complex reconstruction, reduce left ventricular (LV) volume associated with improvement of symptoms of heart failure.
Twelve consecutive patients with end-stage heart failure due to nonischemic dilated cardiomyopathy (DCM) (n = 6) and ischemic dilated cardiomyopathy (ICM) (n = 6) who underwent SVR were studied. Myocardial oxidative metabolism per gram of tissue was estimated by monoexponential clearance of (11)C-acetate positron emission tomography (K(mono)). Forward stroke volume at the LV outflow tract was measured by echocardiography. Cardiac efficiency was estimated by the ratio of external work (stroke volume at the LV outflow tract index × systolic blood pressure × heart rate) to K(mono) before and 1 month after SVR.
After SVR, medians of New York Heart Association functional class significantly improved from 3 to 1.5 (p < 0.01) in both DCM and ICM patients. End-systolic and end-diastolic volume and LV mass significantly decreased in both groups. Stroke volume at the LV outflow tract increased from 43 ± 8 ml to 52 ± 11 ml (p = 0.028) in DCM patients, but not in ICM patients (49 ± 21 ml to 59 ± 26 ml, p = 0.12). K(mono) × LV mass, as an index of global LV oxidative metabolism, decreased in DCM patients (13.6 ± 1.9 g/min vs. 8.6 ± 1.5 g/min, p = 0.03) and ICM patients (12.0 ± 3.4 g/min vs. 9.2 ± 1.0 g/min, p = 0.06). As a result, cardiac efficiency increased in all patients with DCM (3.34 ± 0.46 × 10E6 vs. 4.74 ± 0.88 × 10E6 mm Hg·ml·min/m(2), p = 0.03) and in 5 of 6 patients with ICM (4.54 ± 1.66 × 10E6 vs. 5.99 ± 2.11 × 10E6 mm Hg·ml·min/m(2), p = 0.12).
Combined surgery with SVR and mitral complex reconstruction reduced LV volume in association with improvement of cardiac efficiency in patients with severe heart failure.
JACC. Cardiovascular imaging 07/2011; 4(7):762-70. · 14.29 Impact Factor
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ABSTRACT: Smoking cessation has been shown to normalize the coronary endothelial dysfunction in healthy young smokers. However, its effect has not been explored in middle-aged smokers with a longer history of smoking. Therefore, we compared the effects of smoking cessation on coronary vasomotor response between both young and middle-aged smokers and identified the predictor for its improvement.
This study investigated 14 young healthy smokers (age 25.2 ± 2.3 years), 13 middle-aged smokers (age 42.0 ± 6.5 years) and 10 non-smokers. Myocardial blood flow (MBF) was measured by using (15)O-water positron emission tomography (PET).
At baseline, the ratio of MBF during the cold pressor test (CPT) to that at rest (MBF(CPT/rest)), the index of coronary endothelial function, was significantly decreased in both young and middle-aged smokers compared to non-smokers (1.24 ± 0.20 and 1.10 ± 0.39 vs 1.53 ± 0.18, p < 0.05 and p < 0.001, respectively). The ratio of MBF during adenosine triphosphate infusion to that at rest was significantly decreased in middle-aged smokers compared to young smokers and non-smokers (3.34 ± 1.52 vs 4.43 ± 0.92 and 4.69 ± 1.25, p < 0.05, respectively). MBF(CPT/rest) at 1 month after smoking cessation significantly increased in young smokers, but not in middle-aged smokers. By multivariate analysis, baseline serum malondialdehyde-modified low-density lipoprotein (MDA-LDL) was an independent predictor for the changes in MBF(CPT/rest) after smoking cessation (β = -0.45, p < 0.05).
Coronary endothelial dysfunction was reversible by short-term smoking cessation in young smokers, but not in middle-aged smokers, which was associated with serum MDA-LDL levels. Long-term smoking exposure could lead to more advanced coronary endothelial dysfunction and atherosclerosis possibly via oxidative stress.
European Journal of Nuclear Medicine 03/2011; 38(3):491-8. · 4.53 Impact Factor
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ABSTRACT: Endothelial dysfunction is the earliest abnormality in the development of coronary atherosclerosis. 82Rb is a generator-produced positron emission tomography (PET) myocardial perfusion tracer that is becoming more widely used. We aimed to (1) develop a method for quantitative assessment of coronary endothelial function using the myocardial blood flow (MBF) response during a cold pressor test (CPT) in smokers, measured using 82Rb PET, and (2) compare the results with those measured using 15O-water PET.
MBF was assessed at rest and during the CPT with 82Rb and 15O-water in nine controls and ten smokers. A one-compartment model with tracer extraction correction was used to estimate MBF with both tracers. CPT response was calculated as the ratio of MBF during the CPT to MBF at rest.
At rest, measurements of MBF for smokers vs controls were not different using 15O-water (0.86±0.18 vs 0.70±0.13, p=0.426) than they were using 82Rb (0.83±0.23 vs 0.62±0.20, p=0.051). Both methods showed a reduced CPT response in smokers vs controls (15O-water, 1.03±0.21 vs 1.42±0.29, p=0.006; 82Rb, 1.02±0.28 vs 1.70±0.52, p<0.001). There was high reliability [intraclass correlation coefficients: 0.48 (0.07, 0.75)] of MBF measurement between 82Rb and 15O-water during the CPT.
Using a CPT, 82Rb MBF measurements detected coronary endothelial dysfunctions in smokers. 82Rb MBF measurements were comparable to those made using the 15O-water approach. Thus, 82Rb PET may be applicable for risk assessments or evaluation of risk factor modification in subjects with coronary risk factors.
European Journal of Nuclear Medicine 12/2010; 37(12):2233-41. · 4.53 Impact Factor
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ABSTRACT: The relationship between myocardial oxidative metabolism and pressure overload in aortic valve stenosis (AS) is not fully elucidated. We identified the determinants of myocardial oxidative metabolism by measuring its changes after aortic valve replacement (AVR) in patients with AS.
Myocardial 11C-acetate clearance rate constant (Kmono), an index of oxidative metabolism, was measured non-invasively by using positron emission tomography in 16 patients with moderate to severe AS and 7 healthy controls. The severity of AS was assessed by echocardiography. Of 16 patients, 5 were reexamined at 1 month after AVR.
Kmono was significantly higher in patients with AS than healthy controls by 42% (0.068±0.014 vs 0.048±0.007/min, p<0.01). Kmono was significantly correlated with age (r=0.58, p<0.01), left ventricular (LV) mass index (r=0.61, p<0.01) and estimated systolic LV pressure (r=0.81, p<0.001) measured by echocardiography. By multivariate analysis, estimated LV systolic pressure was an independent predictor of Kmono (β=0.93, p<0.01). After AVR, Kmono (from 0.075±0.012 to 0.061±0.014/min, p=0.043) and LV mass index (from 183±49 to 124±41 g/ml2, p=0.043) were significantly decreased despite no significant changes in rate-pressure product.
Myocardial oxygen metabolism was increased in patients with AS, which was decreased after AVR. The increased myocardial oxidative metabolism in AS was largely attributable to the pressure overload of the LV.
European Journal of Nuclear Medicine 12/2010; 37(12):2242-8. · 4.53 Impact Factor
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ABSTRACT: Cardiac PET has the unique ability to assess coronary flow reserve and coronary endothelial function on the basis of response of blood flow to pharmacological stress and the cold pressor test. Quantitative analysis of coronary vasomotor function is valuable for precise assessment of function and treatment monitoring in the presence of various coronary risk factors. In addition, recent data have shown prognostic value of PET assessment of coronary vasomotor imaging in patients with suspected coronary artery disease. Thus, quantitative analysis of PET has a great potential for wide application in identifying microcirculatory dysfunction and "individualized" monitoring of the effects of primary or preventive medical intervention to optimize cardiovascular outcome.
European Journal of Nuclear Medicine 11/2009; 37(6):1213-24. · 4.53 Impact Factor
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ABSTRACT: The repeatability of rest and hyperemic myocardial blood flow (MBF) measurements using 82Rb PET has not been evaluated. The aim of this study was to investigate the short-term repeatability of such measurements.
Fifteen healthy volunteers underwent rest and pharmacologic stress 82Rb PET, repeated 60 min apart.
There was no significant difference in repeated rest MBF (0.77+/-0.25 vs. 0.82+/-0.25 mL/min/g, P=0.31; mean difference, 6.18%+/-12.22%) or repeated hyperemic MBF (3.35+/-1.37 vs. 3.39+/-1.37 mL/min/g, P=0.81; mean difference, 1.17%+/-13.64%). The repeatability coefficients were 0.19 mL/min/g for rest MBF and 0.92 mL/min/g for hyperemia.
MBF using 82Rb is highly reproducible using a same-day short-term repeatability protocol. Serial MBF measurements with 82Rb PET should have the ability to quantify the acute effects of therapeutic interventions on MBF.
Journal of Nuclear Medicine 01/2009; 50(1):68-71. · 6.38 Impact Factor
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ABSTRACT: We evaluated whether myocardial beta-adrenergic receptor (beta-AR) density, as determined by 11C-CGP12177 PET, could predict improvement of cardiac function by beta-blocker carvedilol treatment in patients with idiopathic dilated cardiomyopathy (IDC).
Ten patients with IDC (left ventricular ejection fraction [LVEF]<45%) were studied. Myocardial beta-AR density was estimated using 11C-CGP12177 PET before treatment with carvedilol. Changes of LVEF in response to dobutamine infusion (DeltaLVEF-dobutamine) were also measured by echocardiography. Changes of LVEF (DeltaLVEF-carvedilol) were evaluated after 20 mo of carvedilol treatment.
Baseline myocardial beta-AR density significantly correlated with DeltaLVEF-carvedilol (r=-0.88, P<0.001). In contrast, DeltaLVEF-dobutamine did not correlate with DeltaLVEF-carvedilol (P=0.65). Myocardial beta-AR density was the significant multivariate independent predictor of DeltaLVEF-carvedilol (beta=-0.88, P<0.001) among univariate predictors, including functional class (r=0.76, P<0.05), plasma norepinephrine (r=0.85, P<0.01), LVEF (r=-0.64, P<0.05), and age as confounding factors. Furthermore, myocardial beta-AR density was significantly correlated with plasma norepinephrine (r=-0.79, P<0.01) and LVEF (r=0.70, P<0.05).
Myocardial beta-AR density is more tightly related to improvement of LVEF-carvedilol than is cardiac contractile reserve in patients with IDC. Patients with decreased myocardial beta-AR have higher resting adrenergic drive, as reflected by plasma norepinephrine, and may receive greater benefit from being treated by antiadrenergic drugs.
Journal of Nuclear Medicine 01/2009; 50(2):220-5. · 6.38 Impact Factor
