Technical aspects of cardiac PET/MRI

Masuda, Atsuro; Nemoto, Ayaka; Takeishi, Yasuchika

doi:10.1007/s12350-018-1237-4

Cited by 13 publications

(7 citation statements)

References 29 publications

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“…Equipment manufacturers provide attenuation maps for most coils so that they can be automatically combined with the human maps in the AC procedure. Moreover, while both arms should be considered in the AC map, they are truncated in the FOV in the MR images, causing an underestimation of the tumour activity by 10 to 25% [108]. Nevertheless, the truncated arms can be inferred using the maximum-likelihood reconstruction of attenuation and activity procedure [109].…”

Section: Attenuation Correctionmentioning

confidence: 99%

Recent advances in combined Positron Emission Tomography and Magnetic Resonance Imaging

Galve,

Rodriguez-Vila,

Herraiz

et al. 2024

J. Inst.

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Hybrid imaging modalities combine two or more medical imaging techniques offering exciting new possibilities to image the structure, function and biochemistry of the human body in far greater detail than has previously been possible to improve patient diagnosis. In this context, simultaneous Positron Emission Tomography and Magnetic Resonance (PET/MR) imaging offers great complementary information, but it also poses challenges from the point of view of hardware and software compatibility. The PET signal may interfere with the MR magnetic field and vice-versa, posing several challenges and constrains in the PET instrumentation for PET/MR systems. Additionally, anatomical maps are needed to properly apply attenuation and scatter corrections to the resulting reconstructed PET images, as well motion estimates to minimize the effects of movement throughout the acquisition. In this review, we summarize the instrumentation implemented in modern PET scanners to overcome these limitations, describing the historical development of hybrid PET/MR scanners. We pay special attention to the methods used in PET to achieve attenuation, scatter and motion correction when it is combined with MR, and how both imaging modalities may be combined in PET image reconstruction algorithms.

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Section: Attenuation Correctionmentioning

confidence: 99%

Recent advances in combined Positron Emission Tomography and Magnetic Resonance Imaging

Galve,

Rodriguez-Vila,

Herraiz

et al. 2024

J. Inst.

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“…Figure 1 shows rest-pharmacological stress 13 N-ammonia PET/MRI protocol. To correct for PET attenuation of each patient in supine position, a two-point Dixon MRI sequence was performed at the beginning of the PET recording to obtain an attenuation map 14,15 . After the attenuation correction sequence, the list mode PET scan and 4D-flow cine MR were simultaneously started.…”

Section: N-ammonia Pet/mr Imaging Protocolmentioning

confidence: 99%

Intra-Ventricular Diastolic Hemodynamics under Pharmacological Stress in Patients with Ischemic Heart Disease: Analysis of 4D-Flow and Myocardial Flow Reserve using hybrid¹³N-ammonia Positron Emission Tomography/Magnetic Resonance

Endo,

Fukushima,

Katahira

et al. 2024

Preprint

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Objectives: This study aimed to explore the linkage between intra-left ventricular (LV) diastolic hemodynamics and coronary endothelial function, utilizing four-dimensional (4D) flow magnetic resonance imaging (MR) and myocardial flow reserve (MFR) through simultaneous acquisition using hybrid PETMR system in patients with ischemic heart disease (IHD). Methods: Sixty-eight patients (mean 66 ± 15 years, male 55) with IHD who underwent rest-pharmacological stress 13N-ammonia PET/MR were included. MFR and summed defect score (SSS and SRS for stress and rest) were obtained thorough rest-stress PET images. MR acquisition was performed simultaneously during PET scan to obtain rest-stress 4D flow datasets and followed by cine-MRI for the LV volume measurement. LV diastolic inflow(mL/s), peak velocity(cm/s), and averaged diastolic kinetic energy (KEi)(μJ/mL) indexed with endo-diastolic volume were computed. Results: Diastolic LV inflow parameters and KEi significantly increased in stress scan compared to the rest (74.8 ± 17.5 cm/s vs. 64.5 ± 14.4 cm/s, p<0.0001; 10.1 ± 5.2 vs. 13.3 ± 7.8, p=0.0004 for peak velocity and KEi, respectively). Stress KE showed a significant and weak correlation to MFR and SSS (r = 0.3, p=0.004; r=-0.4, p=0.002 for MFR and SSS, respectively). In patients with MFR above median value (1.76), stress KE significantly elevated from rest KE, while no significant change was observed for the patients with MFR below median (11.0 ± 4.6 vs. 16.2 ± 8.8, p=0.0002; 9.7 ± 5.4 vs. 10.3 ± 5.1 for rest vs. stress, respectively). Conclusion: Non-invasive estimation of diastolic dysfunction derived from 4D-flow demonstrated a significant association with myocardial ischemia and coronary endothelial dysfunction.

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“…The protocol included electrocardiographic-gated balanced steady-state free cine sequences by free-breathing. 10,11) Three standard long-axis views (2-chamber, 3-chamber, and 4-chamber views) and multiple short axis views were acquired, and the slice thickness was 5 mm. The number of phases obtained in each cardiac cycle was 25.…”

Section: Mri Acquisition and Analysismentioning

confidence: 99%

“…Hybrid PET/magnetic resonance imaging (MRI) is used as a novel modality for evaluating cardiac diseases, and is able to yield important information regarding various pathologies through molecular and functional imaging of PET and MRI in a one-stop examination. 10) The assessment of RV dysfunction in addition to blood flow analysis may allow the performance of more precise risk classification of CAD. This study aimed to evaluate the prognostic value of a combined analysis of MFR and RV strain by Figure 1.…”

mentioning

confidence: 99%

Prognostic Value of Simultaneous Analysis with Myocardial Flow Reserve and Right Ventricular Strain by Hybrid <sup>13</sup>N-Ammonia Positron Emission Tomography/Magnetic Resonance Imaging in Coronary Artery Disease

et al. 2022

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Myocardial flow reserve (MFR) derived from 13 N-ammonia positron emission tomography (PET) is used to predict adverse cardiac events in patients with coronary artery disease (CAD). Right ventricular global longitudinal strain (RVGLS) measured by magnetic resonance imaging (MRI) is used to evaluate RV function and predict cardiac events. This study aimed to evaluate the prognostic value of MFR and RVGLS measured by hybrid 13 N-ammonia PET/MRI in patients with CAD.Sixty-one patients who underwent 13 N-ammonia PET/MRI were analyzed. The end points were defined as a composite of all-cause death, myocardial infarction, sustained ventricular arrhythmia, hospitalization due to decompensated heart failure, and revascularization. At a follow-up of 2.8 ± 1.9 years, 21 events had occurred. Kaplan-Meier analysis showed that the event-free rate was significantly lower in the group with MFR < 1.80 than in that with MFR "1.80 (P < 0.001). Additionally, the event-free rate was significantly lower in the group with RVGLS > −18.22% than in that with RVGLS !−18.22% (P = 0.025). After dividing the patients into 4 groups by the median MFR and the median RVGLS, the event-free rate was lowest in the combined group of MFR < 1.80 and RVGLS > −18.22% than any other groups (P < 0.001). In a Cox proportional hazard analysis, MFR and RVGLS were independent predictors of cardiac adverse events in the patients with CAD.The simultaneous assessment of MFR and RVGLS by 13 N-ammonia PET/MRI revealed the feasibility of precise risk stratification for cardiac events in patients with CAD.

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Technical aspects of cardiac PET/MRI

Cited by 13 publications

References 29 publications

Recent advances in combined Positron Emission Tomography and Magnetic Resonance Imaging

Recent advances in combined Positron Emission Tomography and Magnetic Resonance Imaging

Intra-Ventricular Diastolic Hemodynamics under Pharmacological Stress in Patients with Ischemic Heart Disease: Analysis of 4D-Flow and Myocardial Flow Reserve using hybrid¹³N-ammonia Positron Emission Tomography/Magnetic Resonance

Prognostic Value of Simultaneous Analysis with Myocardial Flow Reserve and Right Ventricular Strain by Hybrid <sup>13</sup>N-Ammonia Positron Emission Tomography/Magnetic Resonance Imaging in Coronary Artery Disease

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Technical aspects of cardiac PET/MRI

Cited by 13 publications

References 29 publications

Recent advances in combined Positron Emission Tomography and Magnetic Resonance Imaging

Recent advances in combined Positron Emission Tomography and Magnetic Resonance Imaging

Intra-Ventricular Diastolic Hemodynamics under Pharmacological Stress in Patients with Ischemic Heart Disease: Analysis of 4D-Flow and Myocardial Flow Reserve using hybrid13N-ammonia Positron Emission Tomography/Magnetic Resonance

Prognostic Value of Simultaneous Analysis with Myocardial Flow Reserve and Right Ventricular Strain by Hybrid <sup>13</sup>N-Ammonia Positron Emission Tomography/Magnetic Resonance Imaging in Coronary Artery Disease

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Intra-Ventricular Diastolic Hemodynamics under Pharmacological Stress in Patients with Ischemic Heart Disease: Analysis of 4D-Flow and Myocardial Flow Reserve using hybrid¹³N-ammonia Positron Emission Tomography/Magnetic Resonance