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Sohn JH, Behr SC, Hernandez PM, Seo Y. Quantitative Assessment of Myocardial Ischemia With Positron Emission Tomography. J Thorac Imaging 2023; 38:247-259. [PMID: 33492046 PMCID: PMC8295411 DOI: 10.1097/rti.0000000000000579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Recent advances in positron emission tomography (PET) technology and reconstruction techniques have now made quantitative assessment using cardiac PET readily available in most cardiac PET imaging centers. Multiple PET myocardial perfusion imaging (MPI) radiopharmaceuticals are available for quantitative examination of myocardial ischemia, with each having distinct convenience and accuracy profile. Important properties of these radiopharmaceuticals ( 15 O-water, 13 N-ammonia, 82 Rb, 11 C-acetate, and 18 F-flurpiridaz) including radionuclide half-life, mean positron range in tissue, and the relationship between kinetic parameters and myocardial blood flow (MBF) are presented. Absolute quantification of MBF requires PET MPI to be performed with protocols that allow the generation of dynamic multiframes of reconstructed data. Using a tissue compartment model, the rate constant that governs the rate of PET MPI radiopharmaceutical extraction from the blood plasma to myocardial tissue is calculated. Then, this rate constant ( K1 ) is converted to MBF using an established extraction formula for each radiopharmaceutical. As most of the modern PET scanners acquire the data only in list mode, techniques of processing the list-mode data into dynamic multiframes are also reviewed. Finally, the impact of modern PET technologies such as PET/CT, PET/MR, total-body PET, machine learning/deep learning on comprehensive and quantitative assessment of myocardial ischemia is briefly described in this review.
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Affiliation(s)
- Jae Ho Sohn
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA
| | - Spencer C. Behr
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA
| | | | - Youngho Seo
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA
- Department of Radiation Oncology, University of California, San Francisco, CA
- UC Berkeley-UCSF Graduate Program in Bioengineering, Berkeley and San Francisco, CA
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2
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Zhu Y, Lyu Z, Lu W, Liu Y, Ma T. Fast and Accurate Gamma Imaging System Calibration Based on Deep Denoising Networks and Self-Adaptive Data Clustering. SENSORS (BASEL, SWITZERLAND) 2023; 23:2689. [PMID: 36904898 PMCID: PMC10007588 DOI: 10.3390/s23052689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 02/18/2023] [Accepted: 02/27/2023] [Indexed: 06/18/2023]
Abstract
Gamma imagers play a key role in both industrial and medical applications. Modern gamma imagers typically employ iterative reconstruction methods in which the system matrix (SM) is a key component to obtain high-quality images. An accurate SM could be acquired from an experimental calibration step with a point source across the FOV, but at a cost of long calibration time to suppress noise, posing challenges to real-world applications. In this work, we propose a time-efficient SM calibration approach for a 4π-view gamma imager with short-time measured SM and deep-learning-based denoising. The key steps include decomposing the SM into multiple detector response function (DRF) images, categorizing DRFs into multiple groups with a self-adaptive K-means clustering method to address sensitivity discrepancy, and independently training separate denoising deep networks for each DRF group. We investigate two denoising networks and compare them against a conventional Gaussian filtering method. The results demonstrate that the denoised SM with deep networks faithfully yields a comparable imaging performance with the long-time measured SM. The SM calibration time is reduced from 1.4 h to 8 min. We conclude that the proposed SM denoising approach is promising and effective in enhancing the productivity of the 4π-view gamma imager, and it is also generally applicable to other imaging systems that require an experimental calibration step.
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Affiliation(s)
- Yihang Zhu
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
- Key Laboratory of Particle & Radiation Imaging, Ministry of Education, Tsinghua University, Beijing 100084, China
- Institute for Precision Medicine, Tsinghua University, Beijing 100084, China
| | - Zhenlei Lyu
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
- Key Laboratory of Particle & Radiation Imaging, Ministry of Education, Tsinghua University, Beijing 100084, China
- Institute for Precision Medicine, Tsinghua University, Beijing 100084, China
| | - Wenzhuo Lu
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
- Key Laboratory of Particle & Radiation Imaging, Ministry of Education, Tsinghua University, Beijing 100084, China
| | - Yaqiang Liu
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
- Key Laboratory of Particle & Radiation Imaging, Ministry of Education, Tsinghua University, Beijing 100084, China
| | - Tianyu Ma
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
- Key Laboratory of Particle & Radiation Imaging, Ministry of Education, Tsinghua University, Beijing 100084, China
- Institute for Precision Medicine, Tsinghua University, Beijing 100084, China
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3
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Poitrasson-Rivière A, Moody JB, Renaud JM, Hagio T, Arida-Moody L, Murthy VL, Ficaro EP. Effect of iterations and time of flight on normal distributions of 82Rb PET relative perfusion and myocardial blood flow. J Nucl Cardiol 2022; 29:2612-2623. [PMID: 34448094 DOI: 10.1007/s12350-021-02775-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 08/03/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND As clinical use of myocardial blood flow (MBF) increases, dynamic series are becoming part of the typical workflow. The methods and parameters used to reconstruct these series require investigation to ensure accurate quantification. METHODS Fifty-nine rest/stress dynamic 82Rb PET studies, acquired on a Biograph mCT, from a combination of normal volunteers and low-likelihood patients were reconstructed with and without time of flight (TOF) for varying iterations and processed to obtain relative perfusion and MBF polar maps. Regional values from mean polar maps were fit to a linear mixed-effect model to quantify convergence and select the optimal number of iterations. RESULTS TOF reconstructions converged faster and yielded more uniform relative perfusion polar maps. However, the stress MBF distribution for TOF reconstructions was more heterogeneous, with a higher-intensity septal wall. This phenomenon requires further investigation, with right ventricle blood pool spillover possibly having an effect. Optimal reconstructions were defined as 5-iteration non-TOF (24-subset) reconstructions and 3-iteration TOF (21-subset) reconstructions. CONCLUSION Optimal cardiac reconstructions were identified for non-TOF and TOF reconstructions of dynamic series. TOF reconstruction presents as the more accurate method, given the more uniform relative perfusion distribution.
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Affiliation(s)
| | - Jonathan B Moody
- INVIA Medical Imaging Solutions, 3025 Boardwalk Drive, Suite 200, Ann Arbor, MI, 48108, USA
| | - Jennifer M Renaud
- INVIA Medical Imaging Solutions, 3025 Boardwalk Drive, Suite 200, Ann Arbor, MI, 48108, USA
| | - Tomoe Hagio
- INVIA Medical Imaging Solutions, 3025 Boardwalk Drive, Suite 200, Ann Arbor, MI, 48108, USA
| | - Liliana Arida-Moody
- Division of Cardiovascular Medicine, Department of Internal Medicine and Frankel Cardiovascular Center, University of Michigan, Ann Arbor, MI, USA
| | - Venkatesh L Murthy
- Division of Cardiovascular Medicine, Department of Internal Medicine and Frankel Cardiovascular Center, University of Michigan, Ann Arbor, MI, USA
| | - Edward P Ficaro
- INVIA Medical Imaging Solutions, 3025 Boardwalk Drive, Suite 200, Ann Arbor, MI, 48108, USA
- Division of Cardiovascular Medicine, Department of Internal Medicine and Frankel Cardiovascular Center, University of Michigan, Ann Arbor, MI, USA
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Abstract
PET/CT has become a preferred imaging modality over PET-only scanners in clinical practice. However, along with the significant improvement in diagnostic accuracy and patient throughput, pitfalls on PET/CT are reported as well. This review provides a general overview on the potential influence of the limitations with respect to PET/CT instrumentation and artifacts associated with the modality integration on the image appearance and quantitative accuracy of PET. Approaches proposed in literature to address the limitations or minimize the artifacts are discussed as well as their current challenges for clinical applications. Although the CT component can play an important role in assisting clinical diagnosis, we concentrate on the imaging scenarios where CT is used to provide auxiliary information for attenuation compensation and scatter correction in PET.
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Affiliation(s)
- Yu-Jung Tsai
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT
| | - Chi Liu
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT; Department of Biomedical Engineering, Yale University, New Haven, CT.
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5
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Case JA. The Importance of Time-of-Flight Reconstruction and Point Spread Modeling in the Measurement of Myocardial Blood Flow Parameters. Curr Cardiol Rep 2021; 23:77. [PMID: 34081208 DOI: 10.1007/s11886-021-01507-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/14/2021] [Indexed: 11/29/2022]
Abstract
PURPOSE OF REVIEW Absolute quantitation of myocardial blood flow has been recognized as one of the most important advances in nuclear cardiology. The addition of absolute myocardial blood flow quantitation has had a significant impact on the determination of normalcy, artifact/defect differentiation, and the true extent of coronary artery disease in patients with known or suspected coronary disease. Time-of-flight reconstruction and point spread function modeling of the potential to greatly improve resolution and signal to background. This combined with absolute blood flow measurements could improve the reliability of regional blood flow estimates and overall image quality. RECENT FINDINGS Recent publications have demonstrated that time-of-flight reconstruction can have an impact on the amount of spillover between the blood pool ROI and the myocardial regions. This may necessitate changes to kinetic models; however, these changes if implemented correctly may result in improved accuracy and reproducibility of blood flow estimates. This may also have the benefit of assessing blood flow in the microvasculature using newer F-18 labeled blood flow tracers. Time of flight and point spread function modeling represent significant improvements in the accuracy and quality of reconstructed myocardial perfusion PET images. This may also have significant implications for the reliability of blood flow estimates. To achieve these benefits, attention must be given to blood flow models to ensure that they have been correctly optimized for the scanner-specific time-of-flight reconstruction properties.
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Affiliation(s)
- James A Case
- Cardiovascular Imaging Technologies, 4320 Wornall Rd., Suite 114, Kansas City, MO, 64111, USA.
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6
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Efthimiou N, Kratochwil N, Gundacker S, Polesel A, Salomoni M, Auffray E, Pizzichemi M. TOF-PET Image Reconstruction With Multiple Timing Kernels Applied on Cherenkov Radiation in BGO. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2020; 5:703-711. [PMID: 34541434 PMCID: PMC8445518 DOI: 10.1109/trpms.2020.3048642] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Today Time-of-Flight (TOF), in PET scanners, assumes a single, well-defined timing resolution for all events. However, recent BGO-Cherenkov detectors, combining prompt Cherenkov emission and the typical BGO scintillation, can sort events into multiple timing kernels, best described by the Gaussian mixture models. The number of Cherenkov photons detected per event impacts directly the detector time resolution and signal rise time, which can later be used to improve the coincidence timing resolution. This work presents a simulation toolkit which applies multiple timing spreads on the coincident events and an image reconstruction that incorporates this information. A full cylindrical BGO-Cherenkov PET model was compared, in terms of contrast recovery and contrast-to-noise ratio, against an LYSO model with a time resolution of 213 ps. Two reconstruction approaches for the mixture kernels were tested: 1) mixture Gaussian and 2) decomposed simple Gaussian kernels. The decomposed model used the exact mixture component applied during the simulation. Images reconstructed using mixture kernels provided similar mean value and less noise than the decomposed. However, typically, more iterations were needed. Similarly, the LYSO model, with a single TOF kernel, converged faster than the BGO-Cherenkov with multiple kernels. The results indicate that the model complexity slows down convergence. However, due to the higher sensitivity, the contrast-to-noise ratio was 26.4% better for the BGO model.
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Affiliation(s)
- Nikos Efthimiou
- Department Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104 USA
| | | | - Stefan Gundacker
- Department of Physics of Molecular Imaging Systems, Institute for Experimental Molecular Imaging, RWTH Aachen University, 52062 Aachen, Germany
| | - Andrea Polesel
- Physics Department, University of Milano-Bicocca, 20126 Milan, Italy
| | - Matteo Salomoni
- Physics Department, University of Milano-Bicocca, 20126 Milan, Italy
| | | | - Marco Pizzichemi
- Physics Department, University of Milano-Bicocca, 20126 Milan, Italy
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7
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Wang Y, Li Y, Yi F, Li J, Xie S, Peng Q, Xu J. Two-crossed-polarizers based optical property modulation method for ionizing radiation detection for positron emission tomography. Phys Med Biol 2019; 64:135017. [PMID: 31117057 DOI: 10.1088/1361-6560/ab23cb] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Recent work shows that Pockels effect and optics pump-probe measurement could be utilized as a novel method for 511 keV ionizing radiation photon detection for positron emission tomography (PET) which could potentially overcome the inherent physical limitation for coincidence time resolution of around 100 ps (Tao et al 2016 Phys. Med. Biol. 61 7600-22). In this paper, we embrace this observation and introduce a two-crossed-polarizers based setup to achieve similar detection concept, which is a simpler and more compact setup with comparable ionizing radiation detection capability as the setup used in the previously proposed work. We evaluated the performance of our experimental setup with Lithium Niobate (LiNbO3) and Cadmium Telluride (CdTe) detector crystals, and the desired properties of an ideal detector crystal were discussed. The modulation signal induced by 511 keV photons in both LiNbO3 and CdTe can be detected with repeatable signal amplitude using two-crossed-polarizers based method, while CdTe could provide eight times higher detection sensitivity to 511 keV photons than LiNbO3 under the same bias voltage, suggesting high effective Z number and high density properties of CdTe, as well as a shorter carrier lifetime and lower carrier mobility of LiNbO3. In addition, the strength of modulation signal increased linearly with bias voltage before saturation. The modulation signal strength in LiNbO3 continued to increase after 2000 V due to its high resistivity which could reduce the dark current in the detector, while the modulation signal of CdTe with low resistivity tended to be saturated at a bias voltage higher than 1200 V. Therefore, further increasing the bias voltage for detector crystals (especially for LiNbO3) may enhance the modulation strength and improve the detection sensitivity for annihilation photons.
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Affiliation(s)
- Yuli Wang
- China-EU Institute for Clean and Renewable Energy, Huazhong University of Science and Technology, Wuhan, Hubei 430074, People's Republic of China. State Key Laboratory of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, People's Republic of China
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8
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Memmott MJ, Tonge CM, Saint KJ, Arumugam P. Impact of pharmacological stress agent on patient motion during rubidium-82 myocardial perfusion PET/CT. J Nucl Cardiol 2018; 25:1286-1295. [PMID: 28054183 DOI: 10.1007/s12350-016-0767-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 12/06/2016] [Indexed: 10/20/2022]
Abstract
BACKGROUND Patient motion has been demonstrated to have a significant impact on the quality and accuracy of rubidium-82 myocardial perfusion PET/CT. This study aimed to investigate the effect on patient motion of two pharmacological stressing agents, adenosine and regadenoson. METHODS AND RESULTS Dynamic data were retrospectively analyzed in 90 patients undergoing adenosine (n = 30), incremental adenosine (n = 30), or regadenoson (n = 30) rubidium-82 myocardial perfusion PET/CT. Severity of motion was scored qualitatively using a four-point (0-3) scale and quantitatively using frame-to-frame pixel shifts. The type of motion, returning or non-returning, and the frame in which it occurred were also recorded. There were significant differences in both the qualitative and quantitative scores comparing regadenoson to adenosine (P = .025 and P < .001) and incremental adenosine (P = .014, P = .015), respectively. The difference in scores between adenosine and incremental adenosine was not significant. Where motion was present, significantly more adenosine patients were classed as non-returning (P = .018). The median frames for motion occurring were 12 for regadenoson and 14 for both adenosine cohorts. CONCLUSIONS The choice of stressing protocol impacts significantly on patient motion. Patients stressed with regadenoson have significantly lower motion scores than those stressed with adenosine, using local protocols. This motion is more likely to be associated with a drift of the heart away from a baseline position, coinciding with the termination of infusion.
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Affiliation(s)
- Matthew J Memmott
- Nuclear Medicine, Central Manchester University Hospitals, Oxford Road, Manchester, M13 9WL, United Kingdom.
| | - Christine M Tonge
- Nuclear Medicine, Central Manchester University Hospitals, Oxford Road, Manchester, M13 9WL, United Kingdom
| | - Kimberley J Saint
- Nuclear Medicine, Central Manchester University Hospitals, Oxford Road, Manchester, M13 9WL, United Kingdom
| | - Parthiban Arumugam
- Nuclear Medicine, Central Manchester University Hospitals, Oxford Road, Manchester, M13 9WL, United Kingdom
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9
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Armstrong IS, Memmott MJ, Tonge CM, Arumugam P. The impact of prompt gamma compensation on myocardial blood flow measurements with rubidium-82 dynamic PET. J Nucl Cardiol 2018; 25:596-605. [PMID: 27624818 DOI: 10.1007/s12350-016-0583-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2016] [Accepted: 06/17/2016] [Indexed: 12/23/2022]
Abstract
BACKGROUND Rubidium-82 myocardial perfusion imaging is a well-established technique for assessing myocardial ischemia. With continuing interest on myocardial blood flow (MBF) and myocardial flow reserve (MFR) measurements, there is a requirement to fully appreciate the impact of technical aspects of the process. One such factor for rubidium-82 is prompt gamma compensation (PGC). This study aims to assess the impact of PGC on MBF and MFR calculated from dynamic Rb-82 data. METHODS Dynamic rest and stress images were acquired on a Siemens Biograph mCT and reconstructed with and without PGC in 50 patients (29 male). MBF and MFR were measured in the three main coronary territories as well as globally. RESULTS With PGC, statistically significant reductions in MBF were observed in LAD (-6.9%), LCx (-4.8%), and globally (-6.5%) but only in obese patients. Significant increases in MBF were observed in RCA (+6.4%) in only nonobese patients. In very obese patients, differences of up to 40% in MBF were observed between PGC and non-PGC images. In nearly all cases, similar PGC differences were observed at stress and rest so there were no significant differences in MFR; however, in a small number of very obese patients, differences in excess of 20% were observed. CONCLUSION PGC results in statistically significant changes in MBF, with the greatest reductions observed in the LAD and LCx territories of obese patients. In most cases, the impact on stress and rest data is of similar relative magnitudes and changes to MFR are small.
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Affiliation(s)
- Ian S Armstrong
- Nuclear Medicine, Central Manchester University Hospitals, Oxford Road, Manchester, M13 9WL, United Kingdom.
| | - Matthew J Memmott
- Nuclear Medicine, Central Manchester University Hospitals, Oxford Road, Manchester, M13 9WL, United Kingdom
| | - Christine M Tonge
- Nuclear Medicine, Central Manchester University Hospitals, Oxford Road, Manchester, M13 9WL, United Kingdom
| | - Parthiban Arumugam
- Nuclear Medicine, Central Manchester University Hospitals, Oxford Road, Manchester, M13 9WL, United Kingdom
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10
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Piccinelli M, Votaw JR, Garcia EV. Motion Correction and Its Impact on Absolute Myocardial Blood Flow Measures with PET. Curr Cardiol Rep 2018; 20:34. [PMID: 29574494 DOI: 10.1007/s11886-018-0977-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
PURPOSE OF REVIEW Motion artifacts, due to cardiac and respiratory cycles, myocardial cardiac creep, or gross patient movements, have been extensively investigated in the context of relative myocardial perfusion imaging with SPECT and PET. These movements have been identified as a major source of errors in image quantification and diagnosis. Recently, as dynamic PET quantification for myocardial blood flow assessment has entered clinical practice, similar questions have arisen on the impact of motion on final blood flow values. RECENT FINDINGS While preliminary investigations have underlined the potential impact of these motions on MBF quantification, their correction on dynamic acquisition remains challenging and limited to research studies. Gross patient's body movements occur in a consistent number of cases, particularly during stress acquisition, typically involving a limited number of image frames. If undetected, these movements can lead to great differences in flow values and consequently misdiagnosis. Quality control routines can be applied to automatically inspect the shape of time activity curves and to help identify motion artifacts. Cyclic cardiac and respiratory motion may have a considerable impact on final flow values. Correction of gross body motion represents a priority in the context of optimizing absolute flow clinical routine utilization and protocol standardization.
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Affiliation(s)
- Marina Piccinelli
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Woodruff Memorial Research Building, Room 1203-C, 101 Woodruff Circle, Atlanta, GA, 30322, USA.
| | - John R Votaw
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Woodruff Memorial Research Building, Room 1203-C, 101 Woodruff Circle, Atlanta, GA, 30322, USA.,, Alpharetta, USA
| | - Ernest V Garcia
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Woodruff Memorial Research Building, Room 1203-C, 101 Woodruff Circle, Atlanta, GA, 30322, USA
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11
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Chilra P, Gnesin S, Allenbach G, Monteiro M, Prior JO, Vieira L, Pires Jorge JA. Cardiac PET/CT with Rb-82: optimization of image acquisition and reconstruction parameters. EJNMMI Phys 2017; 4:10. [PMID: 28205113 PMCID: PMC5311016 DOI: 10.1186/s40658-017-0178-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 02/08/2017] [Indexed: 12/04/2022] Open
Abstract
Background Our aim was to characterize the influence of time-of-flight (TOF) and point spread function (PSF) recovery corrections, as well as ordered subset expectation maximization (OSEM) reconstruction parameters, in 82Rb PET/CT quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR). Rest and stress list-mode dynamic 82Rb PET acquisition data from 10 patients without myocardial flow defects and 10 patients with myocardial blood flow defects were reconstructed retrospectively. OSEM reconstructions were performed with Gaussian filters of 4, 6, and 8 mm, different iterations, and subset numbers (2 × 24; 2 × 16; 3 × 16; 4 × 16). Rest and stress global, regional, and segmental MBF and MFR were computed from time activity curves with FlowQuant© software. Left ventricular segmentation using the 17-segment American Heart Association model was obtained. Results Whole left ventricle (LV) MBF at rest and stress were 0.97 ± 0.30 and 2.30 ± 1.00 mL/min/g, respectively, and MFR was 2.40 ± 1.13. Concordance was excellent and all reconstruction parameters had no significant impact on MBF, except for the exclusion of TOF which led to significantly decreased concordance in rest and stress MBF in patients with or without perfusion defects on a coronary artery basis and in MFR in patients with perfusion defects. Conclusions Changes in reconstruction parameters in perfusion 82Rb PET/CT studies influence quantitative MBF analysis. The inclusion of TOF information in the tomographic reconstructions had significant impact in MBF quantification.
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Affiliation(s)
- P Chilra
- Haute École de Santé Vaud - Filière TRM, University of Applied Sciences and Arts Western Switzerland, Lausanne, Switzerland.,Nuclear Medicine and Molecular Imaging Department, Lausanne University Hospital, Lausanne, Switzerland.,Área Científica de Medicina Nuclear, Escola Superior de Tecnologia da Saúde de Lisboa, Instituto Politécnico de Lisboa, Lisbon, Portugal
| | - S Gnesin
- Institute of Radiation Physics, Lausanne University Hospital, Lausanne, Switzerland.,Nuclear Medicine and Molecular Imaging Department, Lausanne University Hospital, Lausanne, Switzerland
| | - G Allenbach
- Nuclear Medicine and Molecular Imaging Department, Lausanne University Hospital, Lausanne, Switzerland
| | - M Monteiro
- Nuclear Medicine and Molecular Imaging Department, Lausanne University Hospital, Lausanne, Switzerland
| | - J O Prior
- Nuclear Medicine and Molecular Imaging Department, Lausanne University Hospital, Lausanne, Switzerland
| | - L Vieira
- Área Científica de Medicina Nuclear, Escola Superior de Tecnologia da Saúde de Lisboa, Instituto Politécnico de Lisboa, Lisbon, Portugal.,Instituto de Biofísica e Engenharia Biomédica, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal
| | - J A Pires Jorge
- Haute École de Santé Vaud - Filière TRM, University of Applied Sciences and Arts Western Switzerland, Lausanne, Switzerland.
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12
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Impact of Time-of-Flight Reconstruction on Cardiac PET Images of Obese Patients. Clin Nucl Med 2017; 42:e103-e108. [DOI: 10.1097/rlu.0000000000001441] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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13
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Slomka PJ, Alessio AM, Germano G. How to reconstruct dynamic cardiac PET data? J Nucl Cardiol 2017; 24:291-293. [PMID: 27473215 DOI: 10.1007/s12350-016-0608-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 07/11/2016] [Indexed: 10/21/2022]
Affiliation(s)
- Piotr J Slomka
- Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
- David Geffen School of Medicine, UCLA, Los Angeles, CA, USA.
| | - Adam M Alessio
- Department of Radiology, University of Washington, Seattle, WA, USA
| | - Guido Germano
- Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
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14
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Germino M, Ropchan J, Mulnix T, Fontaine K, Nabulsi N, Ackah E, Feringa H, Sinusas AJ, Liu C, Carson RE. Quantification of myocardial blood flow with (82)Rb: Validation with (15)O-water using time-of-flight and point-spread-function modeling. EJNMMI Res 2016; 6:68. [PMID: 27650280 PMCID: PMC5030203 DOI: 10.1186/s13550-016-0215-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 06/30/2016] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND We quantified myocardial blood flow with (82)Rb PET using parameters of the generalized Renkin-Crone model estimated from (82)Rb and (15)O-water images reconstructed with time-of-flight and point spread function modeling. Previous estimates of rubidium extraction have used older-generation scanners without time-of-flight or point spread function modeling. We validated image-derived input functions with continuously collected arterial samples. METHODS Nine healthy subjects were scanned at rest and under pharmacological stress on the Siemens Biograph mCT with (82)Rb and (15)O-water PET, undergoing arterial blood sampling with each scan. Image-derived input functions were estimated from the left ventricle cavity and corrected with tracer-specific population-based scale factors determined from arterial data. Kinetic parametric images were generated from the dynamic PET images by fitting the one-tissue compartment model to each voxel's time activity curve. Mean myocardial blood flow was determined from each subject's (15)O-water k 2 images. The parameters of the generalized Renkin-Crone model were estimated from these water-based flows and mean myocardial (82)Rb K 1 estimates. RESULTS Image-derived input functions showed improved agreement with arterial measurements after a scale correction. The Renkin-Crone model fit (a = 0.77, b = 0.39) was similar to those previously published, though b was lower. CONCLUSIONS We have presented parameter estimates for the generalized Renkin-Crone model of extraction for (82)Rb PET using human (82)Rb and (15)O-water PET from high-resolution images using a state-of-the-art time-of-flight-capable scanner. These results provide a state-of-the-art methodology for myocardial blood flow measurement with (82)Rb PET.
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Affiliation(s)
- Mary Germino
- Biomedical Engineering, Yale University, New Haven, CT USA
- PET Center, Yale School of Medicine, PO Box 208048, New Haven, CT 06520-8048 USA
| | - Jim Ropchan
- PET Center, Diagnostic Radiology, School of Medicine, Yale University, New Haven, CT USA
| | - Tim Mulnix
- PET Center, Diagnostic Radiology, School of Medicine, Yale University, New Haven, CT USA
| | - Kathryn Fontaine
- PET Center, Diagnostic Radiology, School of Medicine, Yale University, New Haven, CT USA
| | - Nabeel Nabulsi
- PET Center, Diagnostic Radiology, School of Medicine, Yale University, New Haven, CT USA
| | - Eric Ackah
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University, New Haven, CT USA
| | - Herman Feringa
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University, New Haven, CT USA
| | - Albert J. Sinusas
- Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University, New Haven, CT USA
| | - Chi Liu
- Biomedical Engineering, Yale University, New Haven, CT USA
- PET Center, Diagnostic Radiology, School of Medicine, Yale University, New Haven, CT USA
| | - Richard E. Carson
- Biomedical Engineering, Yale University, New Haven, CT USA
- PET Center, Diagnostic Radiology, School of Medicine, Yale University, New Haven, CT USA
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15
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Tao L, Daghighian HM, Levin CS. A promising new mechanism of ionizing radiation detection for positron emission tomography: modulation of optical properties. Phys Med Biol 2016; 61:7600-7622. [PMID: 27716640 PMCID: PMC5117889 DOI: 10.1088/0031-9155/61/21/7600] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Using conventional scintillation detection, the fundamental limit in positron emission tomography (PET) time resolution is strongly dependent on the inherent temporal variances generated during the scintillation process, yielding an intrinsic physical limit for the coincidence time resolution of around 100 ps. On the other hand, modulation mechanisms of the optical properties of a material exploited in the optical telecommunications industry can be orders of magnitude faster. In this paper we borrow from the concept of optics pump-probe measurement to for the first time study whether ionizing radiation can produce modulations of optical properties, which can be utilized as a novel method for radiation detection. We show that a refractive index modulation of approximately [Formula: see text] is induced by interactions in a cadmium telluride (CdTe) crystal from a 511 keV photon source. Furthermore, using additional radionuclide sources, we show that the amplitude of the optical modulation signal varies linearly with both the detected event rate and average photon energy of the radiation source.
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Affiliation(s)
- Li Tao
- Department of Electrical Engineering, Stanford University, Stanford, USA
| | | | - Craig S. Levin
- Department of Electrical Engineering, Stanford University, Stanford, USA
- Department of Radiology, Stanford University, Stanford, USA
- Department of Physics, Stanford University, Stanford, USA
- Department of Bioengineering, Stanford University, Stanford, USA
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16
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Presotto L, Busnardo E, Perani D, Gianolli L, Gilardi MC, Bettinardi V. Simultaneous reconstruction of attenuation and activity in cardiac PET can remove CT misalignment artifacts. J Nucl Cardiol 2016; 23:1086-1097. [PMID: 26275447 DOI: 10.1007/s12350-015-0239-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 06/29/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND Misalignment between positron emission tomography (PET) and computed tomography (CT) data is known to generate artifactual defects in cardiac PET images due to imprecise attenuation correction (AC). In this work, the use of a maximum likelihood attenuation and activity (MLAA) algorithm is proposed to avoid such artifacts in time-of-flight (TOF) PET. METHODS MLAA was implemented and tested using a thorax/heart phantom and retrospectively on fourteen (13)N-ammonia PET/CT perfusion studies. Global and local misalignments between PET and CT data were generated by shifting matched CT images or using CT data representative of the end-inspiration phase. PET images were reconstructed with MLAA and a 3D-ordered-subsets-expectation-maximization (OSEM)-TOF algorithm. Images obtained with 3D-OSEM-TOF and matched CT were used as references. These images were compared (qualitatively and semi-quantitatively) with those reconstructed with 3D-OSEM-TOF and MLAA for which a misaligned CT was used, respectively, for AC and initialization. RESULTS Phantom experiment proved the capability of MLAA to converge toward the correct emission and attenuation distributions using, as input, only PET emission data, but convergence was very slow. Initializing MLAA with phantom CT images markedly improved convergence speed. In patient studies, when shifted or end-inspiration CT images were used for AC, 3D-OSEM-TOF reconstructions showed artifacts of increasing severity, size, and frequency with increasing mismatch. Such artifacts were absent in the corresponding MLAA images. CONCLUSION The proposed implementation of the MLAA algorithm is a feasible and robust technique to avoid AC mismatch artifacts in cardiac PET studies provided that a CT of the source is available, even if poorly aligned.
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Affiliation(s)
- L Presotto
- Università Vita-Salute San Raffaele, Milan, Italy.
- In Vivo Human Molecular and Structural Neuroimaging Unit, Division of Neuroscience, IRCCS, San Raffaele Scientific Institute, Milan, Italy.
| | - E Busnardo
- Nuclear Medicine Department, IRCCS, San Raffaele Scientific Institute, Milan, Italy
| | - D Perani
- Università Vita-Salute San Raffaele, Milan, Italy
- In Vivo Human Molecular and Structural Neuroimaging Unit, Division of Neuroscience, IRCCS, San Raffaele Scientific Institute, Milan, Italy
- Nuclear Medicine Department, IRCCS, San Raffaele Scientific Institute, Milan, Italy
| | - L Gianolli
- Nuclear Medicine Department, IRCCS, San Raffaele Scientific Institute, Milan, Italy
| | - M C Gilardi
- IBFM-CNR, Institute for Molecular Bioimaging and Physiology, Segrate, Italy
| | - V Bettinardi
- Nuclear Medicine Department, IRCCS, San Raffaele Scientific Institute, Milan, Italy
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17
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Moody JB, Lee BC, Corbett JR, Ficaro EP, Murthy VL. Precision and accuracy of clinical quantification of myocardial blood flow by dynamic PET: A technical perspective. J Nucl Cardiol 2015; 22:935-51. [PMID: 25868451 DOI: 10.1007/s12350-015-0100-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 02/11/2015] [Indexed: 12/23/2022]
Abstract
A number of exciting advances in PET/CT technology and improvements in methodology have recently converged to enhance the feasibility of routine clinical quantification of myocardial blood flow and flow reserve. Recent promising clinical results are pointing toward an important role for myocardial blood flow in the care of patients. Absolute blood flow quantification can be a powerful clinical tool, but its utility will depend on maintaining precision and accuracy in the face of numerous potential sources of methodological errors. Here we review recent data and highlight the impact of PET instrumentation, image reconstruction, and quantification methods, and we emphasize (82)Rb cardiac PET which currently has the widest clinical application. It will be apparent that more data are needed, particularly in relation to newer PET technologies, as well as clinical standardization of PET protocols and methods. We provide recommendations for the methodological factors considered here. At present, myocardial flow reserve appears to be remarkably robust to various methodological errors; however, with greater attention to and more detailed understanding of these sources of error, the clinical benefits of stress-only blood flow measurement may eventually be more fully realized.
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Affiliation(s)
| | | | - James R Corbett
- Division of Nuclear Medicine, Department of Radiology, University of Michigan, 1338 Cardiovascular Center, 1500 E. Medical Center Dr, SPC 5873, Ann Arbor, MI, 48109-5873, USA
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Edward P Ficaro
- INVIA Medical Imaging Solutions, Ann Arbor, MI, USA
- Division of Nuclear Medicine, Department of Radiology, University of Michigan, 1338 Cardiovascular Center, 1500 E. Medical Center Dr, SPC 5873, Ann Arbor, MI, 48109-5873, USA
| | - Venkatesh L Murthy
- Division of Nuclear Medicine, Department of Radiology, University of Michigan, 1338 Cardiovascular Center, 1500 E. Medical Center Dr, SPC 5873, Ann Arbor, MI, 48109-5873, USA.
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA.
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