| 1. |
- Harms, Hendrik J, et al.
(författare)
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Automatic calculation of myocardial external efficiency using a single 11C-acetate PET scan.
- 2018
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Ingår i: Journal of Nuclear Cardiology. - : Springer Science and Business Media LLC. - 1071-3581 .- 1532-6551. ; 25:6, s. 1937-1944
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Myocardial external efficiency (MEE) is defined as the ratio of kinetic energy associated with cardiac work [forward cardiac output (FCO)*mean systemic pressure] and the chemical energy from oxygen consumed (MVO2) by the left ventricular mass (LVM). We developed a fully automated method for estimating MEE based on a single 11C-acetate PET scan without ECG-gating.METHODS AND RESULTS: Ten healthy controls, 34 patients with aortic valve stenosis (AVS), and 20 patients with mitral valve regurgitation (MVR) were recruited in a dual-center study. MVO2 was calculated using washout of 11C -acetate activity. FCO and LVM were calculated automatically using dynamic PET and parametric image formation. FCO and LVM were also obtained using cardiac magnetic resonance (CMR) in all subjects. The correlation between MEEPET-CMR and MEEPET was high (r = 0.85, P < 0.001) without significant bias. MEEPET was 23.6 ± 4.2% for controls and was lowered in AVS (17.2 ± 4.3%, P < 0.001) and in MVR (18.0 ± 5.2%, P = 0.004). MEEPET was strongly associated with both NYHA class (P < 0.001) and the magnitude of valvular dysfunction (mean aortic gradient: P < 0.001, regurgitant fraction: P = 0.009).CONCLUSION: A single 11C-acetate PET yields accurate and automated MEE results on different scanners. MEE might provide an unbiased measurement of the phenotypic response to valvular disease.
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| 2. |
- Harms, Hendrik J., et al.
(författare)
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Noninvasive Quantification of Myocardial C-11-Meta-Hydroxyephedrine Kinetics
- 2016
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Ingår i: Journal of Nuclear Medicine. - : Society of Nuclear Medicine. - 0161-5505 .- 1535-5667 .- 2159-662X. ; 57:9, s. 1376-1381
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Tidskriftsartikel (refereegranskat)abstract
- C-11-meta-hydroxyephedrine (C-11-HED) kinetics in the myocardium can be quantified using a single-tissue-compartment model together with a metabolite-corrected arterial blood sampler input function (BSIF). The need for arterial blood sampling, however, limits clinical applicability. The purpose of this study was to investigate the feasibility of replacing arterial sampling with imaging-derived input function (IDIF) and venous blood samples. Methods: Twenty patients underwent 60-min dynamic C-11-HED PET/CT scans with online arterial blood sampling. Thirteen of these patients also underwent venous blood sampling. Data were reconstructed using both 3 dimensional row-action maximum-likelihood algorithm (3DR) and a time-of-flight (TF) list-mode reconstruction algorithm. For each reconstruction, IDIF results were compared with BSIF results. In addition, IDIF results obtained with venous blood samples and with a transformed venous-to-arterial metabolite correction were compared with results obtained with arterial metabolite corrections. Results: Correlations between IDIF- and BSIF-derived K-1 and V-T were high (r(2) > =0.89 for 3DR and TF). Slopes of the linear fits were significantly different from 1 for K-1, for both 3DR (slope = 0.94) and TF (slope = 1.06). For V-T, the slope of the linear fit was different from 1 for TF (slope = 0.93) but not for 3DR (slope = 0.98). Use of venous blood data introduced a large bias in V-T (r(2) = 0.96, slope = 0.84) and a small bias in K-1 (r(2) = 0.99, slope = 0.98). Use of a second-order polynomial venous-to-arterial transformation was robust and greatly reduced bias in V-T (r(2) = 0.97, slope = 0.99) with no effect on K-1. Conclusion: IDIF yielded precise results for both 3DR and TF. Venous blood samples can be used for absolute quantification of C-11-HED studies, provided a venous-to-arterial transformation is applied. A venous-to-arterial transformation enables noninvasive, absolute quantification of C-11-HED studies.
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| 3. |
- Harms, Hendrik J, et al.
(författare)
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Use of a Single 11C-Meta-Hydroxyephedrine Scan for Assessing Flow-Innervation Mismatches in Patients with Ischemic Cardiomyopathy
- 2015
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Ingår i: Journal of Nuclear Medicine. - : Society of Nuclear Medicine. - 0161-5505 .- 1535-5667 .- 2159-662X. ; 56:11, s. 1706-1711
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Tidskriftsartikel (refereegranskat)abstract
- UNLABELLED: Mismatch between areas of reduced myocardial blood flow (MBF) and reduced myocardial innervation (defect areas) may be used to estimate the risk for ventricular arrhythmias. The presence of a mismatch zone can be derived using a combined protocol consisting of both an MBF scan and an (11)C-meta-hydroxyephedrine ((11)C-HED) scan. The rate of influx from blood to myocardium (K1) of (11)C-HED is proportional to MBF and can potentially be used as an index for defining MBF defects. The aim of this study was to assess whether K1 derived from an (11)C-HED scan can be used as an index of MBF, potentially allowing for an assessment of MBF-innervation mismatch areas from a single (11)C-HED scan.METHODS: Seventeen patients with known ischemic cardiomyopathy underwent dynamic (15)O-water and (11)C-HED scans. Discrete arterial blood samples were taken during (11)C-HED scans for metabolite correction of the image-derived input function. (11)C-HED influx rate was obtained using a single-tissue-compartment model and compared with transmural MBF (MBFT), defined as MBF as measured with (15)O-water multiplied by perfusable tissue fraction. Defect sizes were obtained from parametric K1 and MBFT images, using 50% of a remote control segment as the cutoff value.RESULTS: There was a significant correlation between MBFT and K1 (y = 0.40x + 0.05 mL·g(-1)·min(-1), r = 0.80, P < 0.001), although K1 was significantly lower than MBFT (slope of the regression line significantly different from 1, P < 0.001). Correlation between MBFT and K1 defect sizes was high (y = 0.89x + 1.38%, r = 0.95, P < 0.001), with no significant difference in mean defect size based on K1 or MBFT (20.9% ± 11.3% and 20.1% ± 10.7% for MBFT and K1, respectively, P = 0.41).CONCLUSION: (11)C-HED influx rate K1 can be used as an alternative to a separate MBF scan for assessing mismatch areas between MBF and myocardial innervation.
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| 4. |
- Kero, Tanja, et al.
(författare)
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Quantitative myocardial blood flow imaging with integrated time-of-flight PET-MR
- 2017
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Ingår i: EJNMMI Physics. - : Springer Science and Business Media LLC. - 2197-7364. ; 4:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The use of integrated PET-MR offers new opportunities for comprehensive assessment of cardiac morphology and function. However, little is known on the quantitative accuracy of cardiac PET imaging with integrated time-of-flight PET-MR. The aim of the present work was to validate the GE Signa PET-MR scanner for quantitative cardiac PET perfusion imaging. Eleven patients (nine male; mean age 59 years; range 46-74 years) with known or suspected coronary artery disease underwent (15)O-water PET scans at rest and during adenosine-induced hyperaemia on a GE Discovery ST PET-CT and a GE Signa PET-MR scanner. PET-MR images were reconstructed using settings recommended by the manufacturer, including time-of-flight (TOF). Data were analysed semi-automatically using Cardiac VUer software, resulting in both parametric myocardial blood flow (MBF) images and segment-based MBF values. Correlation and agreement between PET-CT-based and PET-MR-based MBF values for all three coronary artery territories were assessed using regression analysis and intra-class correlation coefficients (ICC). In addition to the cardiac PET-MR reconstruction protocol as recommended by the manufacturer, comparisons were made using a PET-CT resolution-matched reconstruction protocol both without and with TOF to assess the effect of time-of-flight and reconstruction parameters on quantitative MBF values.RESULTS: Stress MBF data from one patient was excluded due to movement during the PET-CT scanning. Mean MBF values at rest and stress were (0.92 ± 0.12) and (2.74 ± 1.37) mL/g/min for PET-CT and (0.90 ± 0.23) and (2.65 ± 1.15) mL/g/min for PET-MR (p = 0.33 and p = 0.74). ICC between PET-CT-based and PET-MR-based regional MBF was 0.98. Image quality was improved with PET-MR as compared to PET-CT. ICC between PET-MR-based regional MBF with and without TOF and using different filter and reconstruction settings was 1.00.CONCLUSIONS: PET-MR-based MBF values correlated well with PET-CT-based MBF values and the parametric PET-MR images were excellent. TOF and reconstruction settings had little impact on MBF values.
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| 5. |
- Tolbod, Lars P., et al.
(författare)
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Non-invasive quantification of tumor blood flow in prostate cancer using O-15-H2O PET/CT
- 2018
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Ingår i: American Journal of Nuclear Medicine and Molecular Imaging. - : E-CENTURY PUBLISHING CORP. - 2160-8407. ; 8:5, s. 292-302
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Tidskriftsartikel (refereegranskat)abstract
- Tumor blood flow (TBF) measurements in prostate cancer (PCa) provide an integrative index of tumor growth, which could be important for primary diagnosis and therapy response evaluation. O-15-water PET is the noninvasive gold standard but is technically demanding. The aim of this study was to compare the accuracy of three different non-invasive strategies with an invasively measured arterial input function (BSIF): Using image-derived input functions (IDIF) from either 1) a separate heart scan or 2) the pelvic scan or 3) a populations-based input function (PBIF). Nine patients with biopsy-verified PCa scheduled for prostatectomy were included. All patients were characterized with serum levels of PSA (s-PSA), multiparametric magnetic resonance imaging (mpMRl) and post-surgical histopathology Gleason Grade. Dynamic O-15-water was performed of the heart and the pelvic area 15 minutes apart. TBF estimated from both wash-in (K-1) and wash-out (k(2)) constants was calculated using a one-compartmental model. Results: Mean (range) s PSA was 12 (3-27) ng/mL, Gleason Grade Group was 2.9 (1-5), k(2) was 0.44 (0.007-1.2), and K-1 was 0.24 (0.07-0.55) mL,/mL/min. k(2) (BSIF)correlated with s-PSA (r=0.86, P<0.01) and Gleason Grade Group (rho=0.78, P=0.01). BSIF, heart-IDIF and PBIF provided near-identical k(2) and K-1 (r>0.95, P<0.001) with slopes near unity. The correlations of BSIF and pelvic-IDIF rate constants were good (r>0.95, P<0.001), but individual errors high. In conclusion, non-invasive protocols for O-15-water PET with IDIF or PBIF accurately measures perfusion in prostate cancer and might be useful for evaluation of tumor aggressiveness and treatment response.
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