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Robert A Dekemp - One of the best experts on this subject based on the ideXlab platform.

  • comparison of myocardial blood flow and flow reserve with dobutamine and dipyridamole stress using Rubidium 82 positron emission tomography
    Journal of Nuclear Cardiology, 2021
    Co-Authors: Terrence D Ruddy, Rob S. Beanlands, Matthieu Pelletiergalarneau, Paola Ferro, Samuel Patterson, Robert A Dekemp
    Abstract:

    The objective of this study was to compare the hyperemic myocardial blood flow (MBF) and myocardial flow reserve (MFR) obtained with dobutamine to those of dipyridamole in patients referred for myocardial perfusion imaging (MPI) using 82Rb positron emission tomography. One hundred and fifty-six patients who underwent a 82Rb PET MPI study with dobutamine stress were included. A matching cohort of patients who underwent a 82Rb PET MPI study with dipyridamole stress was created, accounting for sex, age, history of coronary artery disease (CAD), prior revascularization, CAD risk factors, body mass index, and MPI interpretation. Global rest MBF (median [interquartile range] 0.84 [0.64-1.00] vs 0.69 [0.59-0.85]), stress MBF (2.36 [1.73-3.08] vs 1.66 [1.25-2.06]), MFR (2.75 [2.19-3.64] vs 2.29 [1.78-2.84]), and corrected MFR (2.85 [2.14-3.64] vs 2.20 [1.65-2.75]) were all significantly higher (P < 0.0001) in the dobutamine cohort compared to the dipyridamole cohort. The results of this study suggest that dobutamine produces higher MBF compared to dipyridamole in a representative population referred to nuclear cardiology laboratories.

  • effect of proton pump inhibitors on Rubidium 82 gastric uptake using positron emission tomography myocardial perfusion imaging
    Journal of Nuclear Cardiology, 2020
    Co-Authors: Robert A Dekemp, Atif Alzahrani, Punitha Arasaratnam, Samia Massalha, Ali Alenazy, Alex Lee, Owen Clarkin, Alomgir Hossain, Rob S. Beanlands
    Abstract:

    Rb-82 positron emission tomography (PET) myocardial perfusion imaging (MPI) is a robust tool for the evaluation of coronary artery disease (CAD). However, gastric uptake and spillover can be seen in 10% of Rb-82 PET MPI studies, commonly affecting the inferior wall, and can preclude the accurate identification of myocardial ischemia. We sought to understand the relationship between Rb-82 gastric uptake and the use of proton pump inhibitors (PPI). 600 consecutive patients who presented for a clinically indicated Rb-82 PET MPI study were prospectively enrolled. In addition to the clinical history, PPI use was ascertained (medication, dose, frequency and duration of use, and time of last dose). Patients were categorized as PPI and non-PPI users. Rb-82 uptake in the gastrium, myocardium, and liver were measured at rest. Absolute uptake values and gastric:hepatic ratios were compared in PPI and non-PPI users. Of 600 enrolled patients, 181 (30.2%) patients were using PPI. The gastric Rb-82 uptake in PPI users was 23% higher than non-PPI users (146 ± 52 kBq/cc vs 119 ± 40 kBq/cc, respectively; P < 0.001). The resting gastric:hepatic Rb-82 uptake ratio was also 23% higher in PPI vs non-PPI users (2.7 ± 1.0 vs 2.2 ± 0.8, respectively; P < 0.001). The gastric uptake of Rb-82 appears to be greater in patients actively using PPI and may identify a group who might be at greater risk of non-diagnostic Rb-82 PET MPI.

  • validation of regional myocardial blood flow quantification using three dimensional pet with Rubidium 82 repeatability and comparison with two dimensional pet data acquisition
    Nuclear Medicine Communications, 2020
    Co-Authors: Osamu Manabe, Robert A Dekemp, Ran Klein, Nagara Tamaki, Chietsugu Katoh, Masanao Naya, Keiichi Magota, Keiichiro Yoshinaga
    Abstract:

    INTRODUCTION Three-dimensional (3D) data acquisition is now standard on PET/computed tomography scanners. The aim of this study was to evaluate the repeatability of myocardial blood flow (MBF) estimation with Rubidium-82 (Rb) 3D PET and to validate regional MBF measurements by comparison with two-dimensional (2D) PET. PATIENTS AND METHODS Fifteen healthy individuals (31.6 ± 11.4 years old) were enrolled for the evaluation of the short-term repeatability of rest 3D MBF quantification. Another 19 healthy individuals (35.3 ± 12.6 years old) underwent rest and pharmacological stress PET using 2D and 3D data acquisition within a 1-month interval. The injected dose was 1500 MBq for 2D and 555 MBq for 3D PET acquisition. RESULTS MBF at rest showed good repeatability [whole left ventricular MBF; 0.54 ± 0.13 vs. 0.52 ± 0.13 mL/min/g, P = 0.98]. Rest MBF, stress MBF, and myocardial flow reserve (MFR) were not significantly different between 3D and 2D data acquisition. 3D MBF correlated well with 2D MBF over a wide flow range for both whole left ventricular (r = 0.97, P < 0.0001) and regional values (r = 0.61, P < 0.0001). CONCLUSION MBF measured with 3D PET showed very good test-retest repeatability. Whole left ventricular and regional MBF measurements obtained using lower Rb-dose 3D PET were highly correlated over a wide range with those from 2D PET. Therefore, MBF with 3D PET can be applied using a lower Rb dosage in clinical settings with reduced radiation exposure.

  • Rubidium 82 generator yield and efficiency for pet perfusion imaging comparison of two clinical systems
    Journal of Nuclear Cardiology, 2020
    Co-Authors: Ali Ahmadi, Ran Klein, Rob S. Beanlands, Howard C Lewin, Robert A Dekemp
    Abstract:

    Strontium-82/Rubidium-82 (82Sr/82Rb) generators are used widely for positron emission tomography (PET) imaging of myocardial perfusion. In this study, the 82Rb isotope yield and production efficiency of two FDA-approved 82Sr/82Rb generators were compared. N = 515 sequential daily quality assurance (QA) reports from 9 CardioGen-82® and 9 RUBY-FILL® generators were reviewed over a period of 2 years. A series of test elutions was performed at different flow-rates on the RUBY-FILL® system to determine an empirical correction-factor used to convert CardioGen-82® daily QA values of 82Rb activity (dose-calibrator ‘maximum’ of 50 mL elution at 50 mL·min−1) to RUBY-FILL® equivalent values (integrated ‘total’ of 35 mL elution at 20 mL·min−1). The generator yield (82Rb) and production efficiency (82Rb yield/82Sr parent activity) were measured and compared after this conversion to a common scale. At the start of clinical use, the system reported 82Rb activity from daily QA was lower for CardioGen-82® vs RUBY-FILL® (2.3 ± 0.2 vs 3.0 ± 0.2 GBq, P < 0.001) despite having similar 82Sr activity. Dose-calibrator ‘maximum’ (CardioGen-82®) values were found to under-estimate the integrated ‘total’ (RUBY-FILL®) activity by ~ 24% at 50 mL·min−1. When these data were used to convert the CardioGen-82 values to a common measurement scale (integrated total activity) the CardioGen-82® efficiency remained slightly lower than the RUBY-FILL® system on average (88 ± 4% vs 95 ± 4%, P < 0.001). The efficiency of 82Rb production improved for both systems over the respective periods of clinical use. 82Rb generator yield was significantly under-estimated using the CardioGen-82® vs RUBY-FILL® daily QA procedure. When generator yield was expressed as the integrated total activity for both systems, the estimated 82Rb production efficiency of the CardioGen-82® system was ~ 7% lower than RUBY-FILL® over the full period of clinical use.

  • dynamic range of the newest digital pet ct scanner for myocardial blood flow quantification using Rubidium 82
    The Journal of Nuclear Medicine, 2020
    Co-Authors: Robert A Dekemp, Ran Klein, Patrick James Genoud, Martin Pappon, Christel Kamani, Silvano Gnesin, John O Prior
    Abstract:

    334 Objectives: Quantification of myocardial blood flow (MBF) has added diagnostic and prognostic value over relative perfusion imaging alone, but requires accurate first-pass dynamic imaging to capture the arterial blood input function. The newest digital PET systems using SiPM technologies have smaller detectors and more counting channels compared to PMT-based systems, potentially reducing detector dead-time losses and increasing dynamic range. This study evaluated the high-count-rate (CR) accuracy of a digital PET system with 3.2mm detectors and 16-to-25 SiPM-to-crystal coupling. Methods: 2200 MBq (60 mCi) of 82Rb was injected into the myocardium compartment of an anthropomorphic torso phantom (Data Spectrum) and scanned for 10 min using a 25 cm axial field-of-view (FOV) digital PET-CT scanner (Siemens Biograph Vision 600). Dynamic images were reconstructed (40 x 15 sec) with all corrections enabled. Time-activity-curves were measured in the heart wall and plotted as a function of total activity in the FOV, and as a function of the prompt coincidence CR (Trues + Scatter + Randoms). Dynamic range was determined as the maximum CR with residual bias<10% in the measured myocardial time-activity data, following the methodology of Renaud et al (J Nucl Med 2017;58(1):103). The corresponding total phantom activity in the FOV was used to estimate the maximum injected dose-by-weight to use for accurate first-pass imaging in patients. Peak first-pass CR was measured as a function of body-weight in N=38 patients, and verified against the predicted phantom CR values. Results: Bias in the measured heart-wall activity was <10% with up to 610 MBq (16.5 mCi) in the cardiac phantom. The prompt CR at this activity was 11.7 Mcps, corresponding to an estimated dose of 12 MBq/kg in a 50kg patient. The patient sample had mean body-weight = 81±19 kg and BMI = 28±6 kg/m2. Patient scans performed using 5-6 MBq/kg (N=21) resulted in a peak CR of 4.8±0.7 Mcps that increased slightly with body weight (R2=0.10, p=0.04), and was consistent with the values predicted by the phantom scan (3.9-4.9 Mcps) representing a 50 kg patient. Patient scans with 6-8 MBq/kg (N=17) showed greater dependence of peak CR with body-weight (R2=0.66, p<0.001), approaching the 11.7 Mcps limit at ~130 kg. In a subset of patients ≤65kg receiving a fixed dose of 370 MBq (N=10), the peak CR tended to decrease with body-weight (R2=0.17, p=0.07). Conclusions: Weight-based dosing up to 6 MBq/kg resulted in peak first-pass CR values well below the accuracy limit of 11.7 Mcps on the Siemens Biograph Vision 600. Patient doses of 6-8 MBq/kg resulted in <10% bias in the peak CR for patients up to 130 kg on average, and should still provide accurate MBF quantification. These results should be confirmed in a larger cohort and in larger patients exceeding 130 kg (285 lbs). References: Renaud JM, Yip K, Guimond J, Trottier M, Pibarot P, Turcotte E, Maguire C, Lalonde L, Gulenchyn K, Farncombe T, Wisenberg G, Moody J, Lee B, Port SC, Turkington TG, Beanlands RS, deKemp RA. Characterization of 3-Dimensional PET Systems for Accurate Quantification of Myocardial Blood Flow. J Nucl Med. 2017 Jan;58(1):103-109. doi: 10.2967/jnumed.116.174565.

Rob S. Beanlands - One of the best experts on this subject based on the ideXlab platform.

  • comparison of myocardial blood flow and flow reserve with dobutamine and dipyridamole stress using Rubidium 82 positron emission tomography
    Journal of Nuclear Cardiology, 2021
    Co-Authors: Terrence D Ruddy, Rob S. Beanlands, Matthieu Pelletiergalarneau, Paola Ferro, Samuel Patterson, Robert A Dekemp
    Abstract:

    The objective of this study was to compare the hyperemic myocardial blood flow (MBF) and myocardial flow reserve (MFR) obtained with dobutamine to those of dipyridamole in patients referred for myocardial perfusion imaging (MPI) using 82Rb positron emission tomography. One hundred and fifty-six patients who underwent a 82Rb PET MPI study with dobutamine stress were included. A matching cohort of patients who underwent a 82Rb PET MPI study with dipyridamole stress was created, accounting for sex, age, history of coronary artery disease (CAD), prior revascularization, CAD risk factors, body mass index, and MPI interpretation. Global rest MBF (median [interquartile range] 0.84 [0.64-1.00] vs 0.69 [0.59-0.85]), stress MBF (2.36 [1.73-3.08] vs 1.66 [1.25-2.06]), MFR (2.75 [2.19-3.64] vs 2.29 [1.78-2.84]), and corrected MFR (2.85 [2.14-3.64] vs 2.20 [1.65-2.75]) were all significantly higher (P < 0.0001) in the dobutamine cohort compared to the dipyridamole cohort. The results of this study suggest that dobutamine produces higher MBF compared to dipyridamole in a representative population referred to nuclear cardiology laboratories.

  • effect of proton pump inhibitors on Rubidium 82 gastric uptake using positron emission tomography myocardial perfusion imaging
    Journal of Nuclear Cardiology, 2020
    Co-Authors: Robert A Dekemp, Atif Alzahrani, Punitha Arasaratnam, Samia Massalha, Ali Alenazy, Alex Lee, Owen Clarkin, Alomgir Hossain, Rob S. Beanlands
    Abstract:

    Rb-82 positron emission tomography (PET) myocardial perfusion imaging (MPI) is a robust tool for the evaluation of coronary artery disease (CAD). However, gastric uptake and spillover can be seen in 10% of Rb-82 PET MPI studies, commonly affecting the inferior wall, and can preclude the accurate identification of myocardial ischemia. We sought to understand the relationship between Rb-82 gastric uptake and the use of proton pump inhibitors (PPI). 600 consecutive patients who presented for a clinically indicated Rb-82 PET MPI study were prospectively enrolled. In addition to the clinical history, PPI use was ascertained (medication, dose, frequency and duration of use, and time of last dose). Patients were categorized as PPI and non-PPI users. Rb-82 uptake in the gastrium, myocardium, and liver were measured at rest. Absolute uptake values and gastric:hepatic ratios were compared in PPI and non-PPI users. Of 600 enrolled patients, 181 (30.2%) patients were using PPI. The gastric Rb-82 uptake in PPI users was 23% higher than non-PPI users (146 ± 52 kBq/cc vs 119 ± 40 kBq/cc, respectively; P < 0.001). The resting gastric:hepatic Rb-82 uptake ratio was also 23% higher in PPI vs non-PPI users (2.7 ± 1.0 vs 2.2 ± 0.8, respectively; P < 0.001). The gastric uptake of Rb-82 appears to be greater in patients actively using PPI and may identify a group who might be at greater risk of non-diagnostic Rb-82 PET MPI.

  • Rubidium 82 generator yield and efficiency for pet perfusion imaging comparison of two clinical systems
    Journal of Nuclear Cardiology, 2020
    Co-Authors: Ali Ahmadi, Ran Klein, Rob S. Beanlands, Howard C Lewin, Robert A Dekemp
    Abstract:

    Strontium-82/Rubidium-82 (82Sr/82Rb) generators are used widely for positron emission tomography (PET) imaging of myocardial perfusion. In this study, the 82Rb isotope yield and production efficiency of two FDA-approved 82Sr/82Rb generators were compared. N = 515 sequential daily quality assurance (QA) reports from 9 CardioGen-82® and 9 RUBY-FILL® generators were reviewed over a period of 2 years. A series of test elutions was performed at different flow-rates on the RUBY-FILL® system to determine an empirical correction-factor used to convert CardioGen-82® daily QA values of 82Rb activity (dose-calibrator ‘maximum’ of 50 mL elution at 50 mL·min−1) to RUBY-FILL® equivalent values (integrated ‘total’ of 35 mL elution at 20 mL·min−1). The generator yield (82Rb) and production efficiency (82Rb yield/82Sr parent activity) were measured and compared after this conversion to a common scale. At the start of clinical use, the system reported 82Rb activity from daily QA was lower for CardioGen-82® vs RUBY-FILL® (2.3 ± 0.2 vs 3.0 ± 0.2 GBq, P < 0.001) despite having similar 82Sr activity. Dose-calibrator ‘maximum’ (CardioGen-82®) values were found to under-estimate the integrated ‘total’ (RUBY-FILL®) activity by ~ 24% at 50 mL·min−1. When these data were used to convert the CardioGen-82 values to a common measurement scale (integrated total activity) the CardioGen-82® efficiency remained slightly lower than the RUBY-FILL® system on average (88 ± 4% vs 95 ± 4%, P < 0.001). The efficiency of 82Rb production improved for both systems over the respective periods of clinical use. 82Rb generator yield was significantly under-estimated using the CardioGen-82® vs RUBY-FILL® daily QA procedure. When generator yield was expressed as the integrated total activity for both systems, the estimated 82Rb production efficiency of the CardioGen-82® system was ~ 7% lower than RUBY-FILL® over the full period of clinical use.

  • comparing yield and efficiency of two approved Rubidium 82 generators for pet imaging
    The Journal of Nuclear Medicine, 2020
    Co-Authors: Ali Ahmadi, Ran Klein, Rob S. Beanlands, Howard C Lewin, Robert A Dekemp
    Abstract:

    1499 Introduction: The exact amount of delivered radioisotopes for perfusion positron emission tomography (PET) is a defining parameter for imaging accuracy and repeatability. In this study the yield and efficiency of two strontium-82/Rubidium-82 (82Sr/82Rb) generators were sought for. Methods: The sequential daily quality assurance (QA) reports from 9 CardioGen-82® and 9 RUBY-FILL® generators were collected for 2 years. A series of test elutions was performed at different flow-rates on the RUBY-FILL® system to determine an empirical correction-factor used to convert CardioGen-82® daily QA values of 82Rb activity (dose-calibrator ‘maximum’ of 50 mL elution at 50 mL/min) to RUBY-FILL® equivalent values (integrated ‘total’ of 35 mL elution at 20 mL/min). The generator yield (82Rb) and production efficiency (82Rb yield / 82Sr parent activity) was measured and compared after this conversion to a common scale. Results: At the start of clinical use, the 82Rb activity measured during daily QA was lower for CardioGen-82® vs RUBY-FILL® (2.3 ± 0.2 vs 3.0 ± 0.2 GBq, p<0.001). Dose-calibrator ‘maximum’ values were found to under-estimate the integrated ‘total’ activity by ~24% at 50 mL/min. After converting the CardioGen-82® values to a common measurement scale (integrated total activity) the CardioGen-82® efficiency remained slightly lower than the RUBY-FILL® system on average (88 ± 4% vs 95 ± 4%, p<0.001). Conclusions: 82Rb generator yield was significantly under-estimated using the CardioGen-82® vs RUBY-FILL® daily QA procedure. At the common scale of integrated total activity, the estimated 82Rb production efficiency of the CardioGen-82® system was ~7% lower than RUBY-FILL® over the full period of clinical use.

  • Rubidium 82 generator yield and efficiency for pet perfusion imaging comparison of two clinical systems
    viXra, 2020
    Co-Authors: Ali Ahmadi, Ran Klein, Rob S. Beanlands, Howard C Lewin, Robert A Dekemp
    Abstract:

    Introduction. Strontium-82/Rubidium-82 (82Sr/82Rb) generators are used widely for positron emission tomography (PET) imaging of myocardial perfusion. In this study, the 82Rb isotope yield and production efficiency of two FDA-approved 82Sr/82Rb generators were compared. Methods. N=515 sequential daily quality assurance (QA) reports from 9 CardioGen-82® and 9 RUBY-FILL® generators were reviewed over a period of 2 years. A series of test elutions was performed at different flow-rates on the RUBY-FILL® system to determine an empirical correction-factor used to convert CardioGen-82® daily QA values of 82Rb activity (dose-calibrator ‘maximum’ of 50 mL elution at 50 mL/min) to RUBY-FILL® equivalent values (integrated ‘total’ of 35 mL elution at 20 mL/min). The generator yield (82Rb) and production efficiency (82Rb yield / 82Sr parent activity) were measured and compared after this conversion to a common scale. Results. At the start of clinical use, the system reported 82Rb activity from daily QA was lower for CardioGen-82® vs RUBY-FILL® (2.3 ± 0.2 vs 3.0 ± 0.2 GBq, p<0.001) despite having similar 82Sr activity. Dose-calibrator ‘maximum’ (CardioGen-82®) values were found to under-estimate the integrated ‘total’ (RUBY-FILL®) activity by ~24% at 50 mL/min. When these data were used to convert the CardioGen-82 values to a common measurement scale (integrated total activity) the CardioGen-82® efficiency remained slightly lower than the RUBY-FILL® system on average (88 ± 4% vs 95 ± 4%, p<0.001). The efficiency of 82Rb production improved for both systems over the respective periods of clinical use. Conclusions. 82Rb generator yield was significantly under-estimated using the CardioGen-82® vs RUBY-FILL® daily QA procedure. When generator yield was expressed as the integrated total activity for both systems, the estimated 82Rb production efficiency of the CardioGen-82® system was ~7% lower than RUBY-FILL® over the full period of clinical use.

Andreas Kjaer - One of the best experts on this subject based on the ideXlab platform.

  • amiodarone attenuates cardiac Rubidium 82 in consecutive pet ct scans in a rodent model
    Journal of Nuclear Cardiology, 2021
    Co-Authors: Simon Bentsen, Philip Hasbak, Andreas Kjaer, Lia E Bang, Rasmus S Ripa
    Abstract:

    Background Risk stratification and diagnosis using Rubidium-82 (82Rb) positron emission tomography (PET) is a routine clinical approach in coronary artery disease (CAD). Various drugs are used to treat CAD; however, whether any of them change the uptake of 82Rb in the heart has not been investigated. The aim of this study is to determine whether drugs used in treatment of CAD affect the uptake of 82Rb in the heart in healthy rats. Methods Seventy-seven Sprague-Dawley rats were included in the cross-sectional study. All rats underwent baseline 82Rb PET/CT and divided into eleven groups treated with different drugs. One group was control group (no treatment), eight groups were treated with monotherapy (amiodarone, acetylsalicylic acid (ASA), clopidogrel, ticagrelor, atorvastatin, enalapril, amlodipine, metoprolol succinate), and two groups were treated with polypharmacy (ASA, ticagrelor, atorvastatin, amlodipine or ASA, clopidogrel, atorvastatin, amlodipine). Once a day, they were administered pharmacological therapy through oral gavage, and on day seven, follow-up scanned with 82Rb PET/CT. Results In the control group without pharmacological treatment, no difference in the standard uptake value (SUV) ratio between heart and muscle from baseline to follow-up (5.8 vs 7.0, P = .3) was found. The group treated with amiodarone had a significantly reduced SUV ratio from baseline to follow-up (5.8 vs 5.1, P = .008). All other drugs investigated had no difference in SUV ratio from baseline to follow-up. Conclusion In this study, we showed that drugs normally used to treat CAD do not affect the uptake of 82Rb. However, amiodarone result in a significantly lowered 82Rb uptake, compared to control. This information about amiodarone would probably not change the size assessment of a myocardial perfusion defect in a clinical setting. However, it could change the kinetic parameters when assessing absolute myocardial blood flow in patients treated with amiodarone.

  • Rubidium 82 positron emission tomography for detection of acute doxorubicin induced cardiac effects in lymphoma patients
    Journal of Nuclear Cardiology, 2020
    Co-Authors: Adam Hogsbro Laursen, Philip Hasbak, Rasmus S Ripa, Andreas Kjaer, Marie Bayer Elming, Lars Kober, Jacob Louis Marott, Jens Jakob Thune, Martin Hutchings
    Abstract:

    Doxorubicin is a cornerstone in lymphoma treatment, but is limited by dose-dependent cardiotoxicity. Rubidium-82 positron emission tomography (82Rb PET) assesses coronary microvascular function through absolute quantification of myocardial perfusion and myocardial perfusion reserve (MPR). Doxorubicin-induced microvascular injury represents a potential early marker of cardiotoxicity. We included 70 lymphoma patients scheduled for doxorubicin-based treatment. Cardiotoxicity was evaluated with 82Rb PET myocardial perfusion imaging during rest and adenosine stress before chemotherapy and shortly after the first doxorubicin exposure. Patients with a MPR decline > 20% were defined as having a low threshold for cardiotoxicity. In the 54 patients with complete data sets, MPR was significantly lower after the initial doxorubicin exposure (2.69 vs 2.51, P = .03). We registered a non-significant decline in stress perfusion (3.18 vs 3.02 ml/g/min, P = .08), but no change in resting myocardial perfusion. There were 13 patients with a low cardiotoxic threshold. These patients had a significantly higher age, but were otherwise similar to the remaining part of the study population. Decreases in MPR after initial doxorubicin exposure in lymphoma patients may represent an early marker of doxorubicin-induced cardiotoxicity. The prognostic value of acute doxorubicin-induced changes in MPR remains to be investigated.

  • reproducibility of lvef lv volumes and lv mass between Rubidium 82 pet ct scans in young healthy volunteers using two commercially available software packages
    Journal of Nuclear Cardiology, 2020
    Co-Authors: Christina Byrne, Andreas Kjaer, Julie Lyng Forman, Philip Hasbak
    Abstract:

    Global functional parameters are available from electrocardiographic gated Rubidium-82 positron emission tomography/computed tomography (82Rb-PET/CT). However, the reproducibility of these data is not clarified. We aimed to investigate reproducibility of left ventricular ejection fraction (LVEF), endsystolic volume (ESV), enddiastolic volume (EDV), and left ventricular (LV) mass between two scans and between two commercially available software packages. Forty healthy young volunteers underwent two 82Rb-PET/CT rest and adenosine stress scans obtaining global functional parameters. Corridor4DM (4DM) and Quantitative Gated SPECT (QGS) were used for analyses. Mean (± SD) age was 24 ± 4 years and 50% were men. High reproducibility of all parameters was found between scans and this was true for both software packages. LVEF at rest with 4DM: mean difference (95% CI) − 1.1 (− 3.0 to 0.8), P = .25, limits of agreement: − 12.8 to 10.6. Significant differences were found between software packages on all functional parameters (P < .0001). High reproducibility was found between scans when measuring LVEF, ESV, EDV, and LV mass from 82Rb-PET/CT. However, concordance between parameter measures was poor when comparing the two software packages. Thus, global functional parameter measures are reliable, but the same software package should be used within a study and when comparing absolute values.

  • Rubidium 82 pet imaging is feasible in a rat myocardial infarction model
    Journal of Nuclear Cardiology, 2019
    Co-Authors: Adam Ali Ghotbi, Andreas Clemmensen, Kasper Kyhl, Bjarke Follin, Philip Hasbak, Thomas Engstrom, Rasmus S Ripa, Andreas Kjaer
    Abstract:

    Background Small-animal myocardial infarct models are frequently used in the assessment of new cardioprotective strategies. A validated quantification of perfusion using a non-cyclotron-dependent PET tracer would be of importance in monitoring response to therapy. We tested whether myocardial PET perfusion imaging is feasible with Rubidium-82 (82Rb) in a small-animal scanner using a rat myocardial infarct model.

  • early risk stratification using Rubidium 82 positron emission tomography in stemi patients
    Journal of Nuclear Cardiology, 2019
    Co-Authors: Adam Ali Ghotbi, Philip Hasbak, Thomas Engstrom, Rasmus S Ripa, Lars Nepperchristensen, Jacob Lonborg, Kiril Atharovski, Thomas Christensen, Lene Holmvang, Andreas Kjaer
    Abstract:

    Assessment of infarct size after myocardial infarction is predictive of subsequent morphological changes and clinical outcome. This study aimed to assess subacute post-intervention Rubidium-82 (82Rb)-PET imaging in predicting left ventricle ejection fraction, regional wall motion, and final infarct size by CMR at 3-months after STEMI. STEMI patients undergoing percutaneous coronary intervention were included prospectively. Rest-only 82Rb-PET perfusion imaging was performed at median 36 hours [IQR: 22 to 50] after the treatment. The extent of hypoperfusion and absolute blood flow (mL·min·g) were estimated on a global and a 17-segment model with dedicated software. At 3-months follow-up patients completed the CMR functional and late gadolinium enhancement imaging. 42 patients were included, but only 35 had follow-up CMR and constituted the study population. Absolute blood flow was significantly lower in the infarct-related territory compared to remote myocardium, P < .005. Extent of hypoperfusion correlated with final infarct size, r = 0.58, P < .001, while blood flow correlated with ejection fraction, r = 0.41, P < .05. In linear mixed models, higher subacute absolute blood flow (β = 4.6, confidence interval [3.5; 5.2], P < .001, R2 = 0.67) was associated with greater wall motion. Segmental extent of subacute hypoperfusion (β = 0.43 [0.38; 0.49], P < .001, R2 = 0.58) was associated with the degree of late gadolinium enhancement at 3-months. Subacute rest-only 82Rb-PET is feasible following STEMI and seems predictive of myocardial function and infarct size at 3-months.

Philip Hasbak - One of the best experts on this subject based on the ideXlab platform.

  • amiodarone attenuates cardiac Rubidium 82 in consecutive pet ct scans in a rodent model
    Journal of Nuclear Cardiology, 2021
    Co-Authors: Simon Bentsen, Philip Hasbak, Andreas Kjaer, Lia E Bang, Rasmus S Ripa
    Abstract:

    Background Risk stratification and diagnosis using Rubidium-82 (82Rb) positron emission tomography (PET) is a routine clinical approach in coronary artery disease (CAD). Various drugs are used to treat CAD; however, whether any of them change the uptake of 82Rb in the heart has not been investigated. The aim of this study is to determine whether drugs used in treatment of CAD affect the uptake of 82Rb in the heart in healthy rats. Methods Seventy-seven Sprague-Dawley rats were included in the cross-sectional study. All rats underwent baseline 82Rb PET/CT and divided into eleven groups treated with different drugs. One group was control group (no treatment), eight groups were treated with monotherapy (amiodarone, acetylsalicylic acid (ASA), clopidogrel, ticagrelor, atorvastatin, enalapril, amlodipine, metoprolol succinate), and two groups were treated with polypharmacy (ASA, ticagrelor, atorvastatin, amlodipine or ASA, clopidogrel, atorvastatin, amlodipine). Once a day, they were administered pharmacological therapy through oral gavage, and on day seven, follow-up scanned with 82Rb PET/CT. Results In the control group without pharmacological treatment, no difference in the standard uptake value (SUV) ratio between heart and muscle from baseline to follow-up (5.8 vs 7.0, P = .3) was found. The group treated with amiodarone had a significantly reduced SUV ratio from baseline to follow-up (5.8 vs 5.1, P = .008). All other drugs investigated had no difference in SUV ratio from baseline to follow-up. Conclusion In this study, we showed that drugs normally used to treat CAD do not affect the uptake of 82Rb. However, amiodarone result in a significantly lowered 82Rb uptake, compared to control. This information about amiodarone would probably not change the size assessment of a myocardial perfusion defect in a clinical setting. However, it could change the kinetic parameters when assessing absolute myocardial blood flow in patients treated with amiodarone.

  • Rubidium 82 positron emission tomography for detection of acute doxorubicin induced cardiac effects in lymphoma patients
    Journal of Nuclear Cardiology, 2020
    Co-Authors: Adam Hogsbro Laursen, Philip Hasbak, Rasmus S Ripa, Andreas Kjaer, Marie Bayer Elming, Lars Kober, Jacob Louis Marott, Jens Jakob Thune, Martin Hutchings
    Abstract:

    Doxorubicin is a cornerstone in lymphoma treatment, but is limited by dose-dependent cardiotoxicity. Rubidium-82 positron emission tomography (82Rb PET) assesses coronary microvascular function through absolute quantification of myocardial perfusion and myocardial perfusion reserve (MPR). Doxorubicin-induced microvascular injury represents a potential early marker of cardiotoxicity. We included 70 lymphoma patients scheduled for doxorubicin-based treatment. Cardiotoxicity was evaluated with 82Rb PET myocardial perfusion imaging during rest and adenosine stress before chemotherapy and shortly after the first doxorubicin exposure. Patients with a MPR decline > 20% were defined as having a low threshold for cardiotoxicity. In the 54 patients with complete data sets, MPR was significantly lower after the initial doxorubicin exposure (2.69 vs 2.51, P = .03). We registered a non-significant decline in stress perfusion (3.18 vs 3.02 ml/g/min, P = .08), but no change in resting myocardial perfusion. There were 13 patients with a low cardiotoxic threshold. These patients had a significantly higher age, but were otherwise similar to the remaining part of the study population. Decreases in MPR after initial doxorubicin exposure in lymphoma patients may represent an early marker of doxorubicin-induced cardiotoxicity. The prognostic value of acute doxorubicin-induced changes in MPR remains to be investigated.

  • reproducibility of lvef lv volumes and lv mass between Rubidium 82 pet ct scans in young healthy volunteers using two commercially available software packages
    Journal of Nuclear Cardiology, 2020
    Co-Authors: Christina Byrne, Andreas Kjaer, Julie Lyng Forman, Philip Hasbak
    Abstract:

    Global functional parameters are available from electrocardiographic gated Rubidium-82 positron emission tomography/computed tomography (82Rb-PET/CT). However, the reproducibility of these data is not clarified. We aimed to investigate reproducibility of left ventricular ejection fraction (LVEF), endsystolic volume (ESV), enddiastolic volume (EDV), and left ventricular (LV) mass between two scans and between two commercially available software packages. Forty healthy young volunteers underwent two 82Rb-PET/CT rest and adenosine stress scans obtaining global functional parameters. Corridor4DM (4DM) and Quantitative Gated SPECT (QGS) were used for analyses. Mean (± SD) age was 24 ± 4 years and 50% were men. High reproducibility of all parameters was found between scans and this was true for both software packages. LVEF at rest with 4DM: mean difference (95% CI) − 1.1 (− 3.0 to 0.8), P = .25, limits of agreement: − 12.8 to 10.6. Significant differences were found between software packages on all functional parameters (P < .0001). High reproducibility was found between scans when measuring LVEF, ESV, EDV, and LV mass from 82Rb-PET/CT. However, concordance between parameter measures was poor when comparing the two software packages. Thus, global functional parameter measures are reliable, but the same software package should be used within a study and when comparing absolute values.

  • Rubidium 82 pet imaging is feasible in a rat myocardial infarction model
    Journal of Nuclear Cardiology, 2019
    Co-Authors: Adam Ali Ghotbi, Andreas Clemmensen, Kasper Kyhl, Bjarke Follin, Philip Hasbak, Thomas Engstrom, Rasmus S Ripa, Andreas Kjaer
    Abstract:

    Background Small-animal myocardial infarct models are frequently used in the assessment of new cardioprotective strategies. A validated quantification of perfusion using a non-cyclotron-dependent PET tracer would be of importance in monitoring response to therapy. We tested whether myocardial PET perfusion imaging is feasible with Rubidium-82 (82Rb) in a small-animal scanner using a rat myocardial infarct model.

  • early risk stratification using Rubidium 82 positron emission tomography in stemi patients
    Journal of Nuclear Cardiology, 2019
    Co-Authors: Adam Ali Ghotbi, Philip Hasbak, Thomas Engstrom, Rasmus S Ripa, Lars Nepperchristensen, Jacob Lonborg, Kiril Atharovski, Thomas Christensen, Lene Holmvang, Andreas Kjaer
    Abstract:

    Assessment of infarct size after myocardial infarction is predictive of subsequent morphological changes and clinical outcome. This study aimed to assess subacute post-intervention Rubidium-82 (82Rb)-PET imaging in predicting left ventricle ejection fraction, regional wall motion, and final infarct size by CMR at 3-months after STEMI. STEMI patients undergoing percutaneous coronary intervention were included prospectively. Rest-only 82Rb-PET perfusion imaging was performed at median 36 hours [IQR: 22 to 50] after the treatment. The extent of hypoperfusion and absolute blood flow (mL·min·g) were estimated on a global and a 17-segment model with dedicated software. At 3-months follow-up patients completed the CMR functional and late gadolinium enhancement imaging. 42 patients were included, but only 35 had follow-up CMR and constituted the study population. Absolute blood flow was significantly lower in the infarct-related territory compared to remote myocardium, P < .005. Extent of hypoperfusion correlated with final infarct size, r = 0.58, P < .001, while blood flow correlated with ejection fraction, r = 0.41, P < .05. In linear mixed models, higher subacute absolute blood flow (β = 4.6, confidence interval [3.5; 5.2], P < .001, R2 = 0.67) was associated with greater wall motion. Segmental extent of subacute hypoperfusion (β = 0.43 [0.38; 0.49], P < .001, R2 = 0.58) was associated with the degree of late gadolinium enhancement at 3-months. Subacute rest-only 82Rb-PET is feasible following STEMI and seems predictive of myocardial function and infarct size at 3-months.

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  • comparison of myocardial blood flow and flow reserve with dobutamine and dipyridamole stress using Rubidium 82 positron emission tomography
    Journal of Nuclear Cardiology, 2021
    Co-Authors: Terrence D Ruddy, Rob S. Beanlands, Matthieu Pelletiergalarneau, Paola Ferro, Samuel Patterson, Robert A Dekemp
    Abstract:

    The objective of this study was to compare the hyperemic myocardial blood flow (MBF) and myocardial flow reserve (MFR) obtained with dobutamine to those of dipyridamole in patients referred for myocardial perfusion imaging (MPI) using 82Rb positron emission tomography. One hundred and fifty-six patients who underwent a 82Rb PET MPI study with dobutamine stress were included. A matching cohort of patients who underwent a 82Rb PET MPI study with dipyridamole stress was created, accounting for sex, age, history of coronary artery disease (CAD), prior revascularization, CAD risk factors, body mass index, and MPI interpretation. Global rest MBF (median [interquartile range] 0.84 [0.64-1.00] vs 0.69 [0.59-0.85]), stress MBF (2.36 [1.73-3.08] vs 1.66 [1.25-2.06]), MFR (2.75 [2.19-3.64] vs 2.29 [1.78-2.84]), and corrected MFR (2.85 [2.14-3.64] vs 2.20 [1.65-2.75]) were all significantly higher (P < 0.0001) in the dobutamine cohort compared to the dipyridamole cohort. The results of this study suggest that dobutamine produces higher MBF compared to dipyridamole in a representative population referred to nuclear cardiology laboratories.

  • abstract 17358 prognostic value of splenic response ratio in Rubidium 82 positron emission tomography myocardial perfusion imaging
    Circulation, 2016
    Co-Authors: Karan Bami, Benjamin J W Chow, Terrence D Ruddy, Robert A Dekemp, Linda Garrard, Rob S. Beanlands, Ann Guo, Shrankhala Tewari, Fadi Guirguis, Girish Dwivedi
    Abstract:

    Introduction: Cardiac magnetic resonance perfusion studies with adenosine stress have shown that splenic response may be a valuable tool to identify patients with inadequate pharmacologic stress. H...

  • prognostic value of Rubidium 82 positron emission tomography in patients after heart transplant
    Circulation-cardiovascular Imaging, 2014
    Co-Authors: Brian Mc Ardle, Terrence D Ruddy, Ross A Davies, Lily Chen, Gary R Small, Girish Dwivedi, Yeung Yam, Haissam Haddad, Lisa Mielniczuk, Ellamae Stadnick
    Abstract:

    Background— Cardiac allograft vasculopathy is a key prognostic determinant after heart transplant. Detection and risk stratification of patients with cardiac allograft vasculopathy are problematic. Positron emission tomography using Rubidium-82 allows quantification of absolute myocardial blood flow and may have utility for risk stratification in this population. Methods and Results— Patients with a history of heart transplant undergoing dipyridamole Rubidium-82 positron emission tomography were prospectively enrolled. Myocardial perfusion and left ventricular ejection fraction were recorded. Absolute flow quantification at rest and after dipyridamole stress as well as the ratio of mean global flow at stress and at rest, termed myocardial flow reserve, were calculated. Patients were followed for all-cause death, acute coronary syndrome, and heart failure hospitalization. A total of 140 patients (81% men; median age, 62 years; median follow-up, 18.2 months) were included. There were 14 events during follow-up (9 deaths, 1 acute coronary syndrome, and 4 heart failure admissions). In addition to baseline clinical variables (estimated glomerular filtration rate, previously documented cardiac allograft vasculopathy), relative perfusion defects, mean myocardial flow reserve, and mean stress myocardial blood flow were significant predictors of adverse outcome. Conclusions— Abnormalities on Rubidium-82 positron emission tomography were predictors of adverse events in heart transplant patients. Larger prospective studies are required to confirm these findings.

  • does quantification of myocardial flow reserve using Rubidium 82 positron emission tomography facilitate detection of multivessel coronary artery disease
    Journal of Nuclear Cardiology, 2012
    Co-Authors: Maria C Ziadi, Benjamin J W Chow, Terrence D Ruddy, Kathryn Williams, Robert A Dekemp, May Aung, Ann Guo, Jennifer Renaud, Ran Klein, Linda Garrard
    Abstract:

    Background Relative myocardial perfusion imaging (MPI) is the standard imaging approach for the diagnosis and prognostic work-up of coronary artery disease (CAD). However, this technique may underestimate the extent of disease in patients with 3-vessel CAD. Positron emission tomography (PET) is also able to quantify myocardial blood flow. Rubidium-82 (82Rb) is a valid PET tracer alternative in centers that lack a cyclotron. The aim of this study was to assess whether assessment of myocardial flow reserve (MFR) measured with 82Rb PET is an independent predictor of severe obstructive 3-vessel CAD.

  • impaired myocardial flow reserve on Rubidium 82 positron emission tomography imaging predicts adverse outcomes in patients assessed for myocardial ischemia
    Journal of the American College of Cardiology, 2011
    Co-Authors: Maria C Ziadi, Benjamin J W Chow, Terrence D Ruddy, Kathryn Williams, Robert A Dekemp, Ann Guo, Jennifer Renaud, Niroshi Sarveswaran, Rebecca E Tee, Rob S. Beanlands
    Abstract:

    Objectives We evaluated the prognostic value of myocardial flow reserve (MFR) using Rubidium-82 (82Rb) positron emission tomography (PET) in patients assessed for ischemia. Background The clinical value of MFR quantification using 82Rb PET beyond relative myocardial perfusion imaging remains uncertain. Methods We prospectively enrolled 704 consecutive patients; 677 (96%) completed follow-up (median 387 days [interquartile range: 375 to 416 days]). Patients were divided into 4 groups: I, normal summed stress score (SSS) ( 2); II, normal SSS and MFR Results For patients with a normal SSS and those with an abnormal SSS, there were significant differences in outcomes for hard events (cardiac death and myocardial infarction) between patients with MFR ≥2 and those with MFR Conclusions MFR quantified using 82Rb PET predicts hard cardiac events and MACE independent of the SSS and other parameters. Routine assessment of 82Rb PET–quantified MFR could improve risk stratification for patients being investigated for ischemia.

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