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Sample records for gated cardiac pet

  1. Respiratory gating in cardiac PET

    DEFF Research Database (Denmark)

    Lassen, Martin Lyngby; Rasmussen, Thomas; Christensen, Thomas E

    2017-01-01

    BACKGROUND: Respiratory motion due to breathing during cardiac positron emission tomography (PET) results in spatial blurring and erroneous tracer quantification. Respiratory gating might represent a solution by dividing the PET coincidence dataset into smaller respiratory phase subsets. The aim...... of our study was to compare the resulting imaging quality by the use of a time-based respiratory gating system in two groups administered either adenosine or dipyridamole as the pharmacological stress agent. METHODS AND RESULTS: Forty-eight patients were randomized to adenosine or dipyridamole cardiac...... stress (82)RB-PET. Respiratory rates and depths were measured by a respiratory gating system in addition to registering actual respiratory rates. Patients undergoing adenosine stress showed a decrease in measured respiratory rate from initial to later scan phase measurements [12.4 (±5.7) vs 5.6 (±4...

  2. An integrated bioimpedance—ECG gating technique for respiratory and cardiac motion compensation in cardiac PET

    International Nuclear Information System (INIS)

    Koivumäki, Tuomas; Nekolla, Stephan G; Fürst, Sebastian; Loher, Simone; Schwaiger, Markus; Vauhkonen, Marko; Hakulinen, Mikko A

    2014-01-01

    Respiratory motion may degrade image quality in cardiac PET imaging. Since cardiac PET studies often involve cardiac gating by ECG, a separate respiratory monitoring system is required increasing the logistic complexity of the examination, in case respiratory gating is also needed. Thus, we investigated the simultaneous acquisition of both respiratory and cardiac gating signals using II limb lead mimicking electrode configuration during cardiac PET scans of 11 patients. In addition to conventional static and ECG-gated images, bioimpedance technique was utilized to generate respiratory- and dual-gated images. The ability of the bioimpedance technique to monitor intrathoracic respiratory motion was assessed estimating cardiac displacement between end-inspiration and -expiration. The relevance of dual gating was evaluated in left ventricular volume and myocardial wall thickness measurements. An average 7.6  ±  3.3 mm respiratory motion was observed in the study population. Dual gating showed a small but significant increase (4 ml, p = 0.042) in left ventricular myocardial volume compared to plain cardiac gating. In addition, a thinner myocardial wall was observed in dual-gated images (9.3  ±  1.3 mm) compared to cardiac-gated images (11.3  ±  1.3 mm, p = 0.003). This study shows the feasibility of bioimpedance measurements for dual gating in a clinical setting. The method enables simultaneous acquisition of respiratory and cardiac gating signals using a single device with standard ECG electrodes. (paper)

  3. Respiratory and cardiac motion correction in dual gated PET/MR imaging

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    Fayad, Hadi; Monnier, Florian [LaTIM, INSERM, UMR 1101, Brest (France); Odille, Freedy; Felblinger, Jacques [INSERM U947, University of Nancy, Nancy (France); Lamare, Frederic [INCIA, UMR5287, CNRS, CHU Bordeaux, Bordeaux (France); Visvikis, Dimitris [LaTIM, INSERM, UMR 1101, Brest (France)

    2015-05-18

    Respiratory and cardiac motion in PET/MR imaging leads to reduced quantitative and qualitative image accuracy. Correction methodologies involve the use of double gated acquisitions which lead to low signal-to-noise ratio (SNR) and to issues concerning the combination of cardiac and respiratory frames. The objective of this work is to use a generalized reconstruction by inversion of coupled systems (GRICS) approach, previously used for PET/MR respiratory motion correction, combined with a cardiac phase signal and a reconstruction incorporated PET motion correction approach in order to reconstruct motion free images from dual gated PET acquisitions. The GRICS method consists of formulating parallel MRI in the presence of patient motion as a coupled inverse problem. Its resolution, using a fixed-point method, allows the reconstructed image to be improved using a motion model constructed from the raw MR data and two respiratory belts. GRICS obtained respiratory displacements are interpolated using the cardiac phase derived from an ECG to model simultaneous cardiac and respiratory motion. Three different volunteer datasets (4DMR acquisitions) were used for evaluation. GATE was used to simulate 4DPET datasets corresponding to the acquired 4DMR images. Simulated data were subsequently binned using 16 cardiac phases (M1) vs diastole only (M2), in combination with 8 respiratory amplitude gates. Respiratory and cardiac motion corrected PET images using either M1 or M2 were compared to respiratory only corrected images and evaluated in terms of SNR and contrast improvement. Significant visual improvements were obtained when correcting simultaneously for respiratory and cardiac motion (using 16 cardiac phase or diastole only) compared to respiratory motion only compensation. Results were confirmed by an associated increased SNR and contrast. Results indicate that using GRICS is an efficient tool for respiratory and cardiac motion correction in dual gated PET/MR imaging.

  4. Dual-gated cardiac PET-clinical feasibility study

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    Teraes, Mika; Kokki, Tommi; Noponen, Tommi; Hoppela, Erika; Sipilae, Hannu T.; Knuuti, Juhani [Turku PET Centre, PO BOX 52, Turku (Finland); Durand-Schaefer, Nicolas [General Electric Medical Systems, Buc (France); Pietilae, Mikko [Turku University Hospital, Department of Internal Medicine, Turku (Finland); Kiss, Jan [Turku University Hospital, Department of Surgery, Turku (Finland)

    2010-03-15

    Both respiratory and cardiac motions reduce image quality in myocardial imaging. For accurate imaging of small structures such as vulnerable coronary plaques, simultaneous cardiac and respiratory gating is warranted. This study tests the feasibility of a recently developed robust method for cardiac-respiratory gating. List-mode data with triggers from respiratory and cardiac cycles are rearranged into dual-gated segments and reconstructed with standard algorithms of a commercial PET/CT scanner. Cardiac gates were defined as three fixed phases and one variable diastolic phase. Chest motion was measured with a respiratory gating device and post-processed to determine gates. Preservation of quantification in dual-gated images was tested with an IEC whole-body phantom. Minipig and human studies were performed to evaluate the feasibility of the method. In minipig studies, a coronary catheter with radioactive tip was guided in coronary artery for in vivo and ex vivo acquisitions. Dual gating in humans with suspected cardiac disorders was performed using 18-F-FDG as a tracer. The method was found feasible for in vivo imaging and the radioactive catheter tip was better resolved in gated images. In human studies, the dual gating was found feasible and easy for clinical routine. Maximal movement of myocardial surface in cranio-caudal direction was over 20 mm. The shape of myocardium was clearly different between the gates and papillary muscles become more visible in diastolic images. The first clinical experiences using robust cardiac-respiratory dual gating are encouraging. Further testing in larger clinical populations using tracers designed especially for plaque imaging is warranted. (orig.)

  5. Dual-gated cardiac PET-clinical feasibility study

    International Nuclear Information System (INIS)

    Teraes, Mika; Kokki, Tommi; Noponen, Tommi; Hoppela, Erika; Sipilae, Hannu T.; Knuuti, Juhani; Durand-Schaefer, Nicolas; Pietilae, Mikko; Kiss, Jan

    2010-01-01

    Both respiratory and cardiac motions reduce image quality in myocardial imaging. For accurate imaging of small structures such as vulnerable coronary plaques, simultaneous cardiac and respiratory gating is warranted. This study tests the feasibility of a recently developed robust method for cardiac-respiratory gating. List-mode data with triggers from respiratory and cardiac cycles are rearranged into dual-gated segments and reconstructed with standard algorithms of a commercial PET/CT scanner. Cardiac gates were defined as three fixed phases and one variable diastolic phase. Chest motion was measured with a respiratory gating device and post-processed to determine gates. Preservation of quantification in dual-gated images was tested with an IEC whole-body phantom. Minipig and human studies were performed to evaluate the feasibility of the method. In minipig studies, a coronary catheter with radioactive tip was guided in coronary artery for in vivo and ex vivo acquisitions. Dual gating in humans with suspected cardiac disorders was performed using 18-F-FDG as a tracer. The method was found feasible for in vivo imaging and the radioactive catheter tip was better resolved in gated images. In human studies, the dual gating was found feasible and easy for clinical routine. Maximal movement of myocardial surface in cranio-caudal direction was over 20 mm. The shape of myocardium was clearly different between the gates and papillary muscles become more visible in diastolic images. The first clinical experiences using robust cardiac-respiratory dual gating are encouraging. Further testing in larger clinical populations using tracers designed especially for plaque imaging is warranted. (orig.)

  6. Automatic cardiac gating of small-animal PET from list-mode data

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    Herraiz, J.L.; Udias, J.M. [Universidad Complutense de Madrid Univ. (Spain). Grupo de Fisica Nuclear; Vaquero, J.J.; Desco, M. [Universidad Carlos III de Madrid (Spain). Dept. de Bioingenieria e Ingenieria Aeroespacial; Cusso, L. [Hospital General Universitario Gregorio Maranon, Madrid (Spain). Unidad de Medicina y Cirugia Experimental

    2011-07-01

    This work presents a method to obtain automatically the cardiac gating signal in a PET study of rats, by employing the variation with time of the counts in the cardiac region, that can be extracted from list-mode data. In an initial step, the cardiac region is identified in the image space by backward-projecting a small fraction of the acquired data and studying the variation with time of the counts in each voxel inside said region, with frequencies within 2 and 8 Hz. The region obtained corresponds accurately to the left-ventricle of the heart of the rat. In a second step, the lines-of-response (LORs) connected with this region are found by forward-projecting this region. The time variation of the number of counts in these LORs contains the cardiac motion information that we want to extract. This variation of counts with time is band-pass filtered to reduce noise, and the time signal so obtained is used to create the gating signal. The result was compared with a cardiac gating signal obtained from an ECG acquired simultaneously to the PET study. Reconstructed gated images obtained from both gating information are similar. The method proposed demonstrates that valid cardiac gating signals can be obtained for rats from PET list-mode data. (orig.)

  7. Acquisition and automated 3-D segmentation of respiratory/cardiac-gated PET transmission images

    International Nuclear Information System (INIS)

    Reutter, B.W.; Klein, G.J.; Brennan, K.M.; Huesman, R.H.

    1996-01-01

    To evaluate the impact of respiratory motion on attenuation correction of cardiac PET data, we acquired and automatically segmented gated transmission data for a dog breathing on its own under gas anesthesia. Data were acquired for 20 min on a CTI/Siemens ECAT EXACT HR (47-slice) scanner configured for 12 gates in a static study, Two respiratory gates were obtained using data from a pneumatic bellows placed around the dog's chest, in conjunction with 6 cardiac gates from standard EKG gating. Both signals were directed to a LabVIEW-controlled Macintosh, which translated them into one of 12 gate addresses. The respiratory gating threshold was placed near end-expiration to acquire 6 cardiac-gated datasets at end-expiration and 6 cardiac-gated datasets during breaths. Breaths occurred about once every 10 sec and lasted about 1-1.5 sec. For each respiratory gate, data were summed over cardiac gates and torso and lung surfaces were segmented automatically using a differential 3-D edge detection algorithm. Three-dimensional visualizations showed that lung surfaces adjacent to the heart translated 9 mm inferiorly during breaths. Our results suggest that respiration-compensated attenuation correction is feasible with a modest amount of gated transmission data and is necessary for accurate quantitation of high-resolution gated cardiac PET data

  8. Evaluation of respiratory and cardiac motion correction schemes in dual gated PET/CT cardiac imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lamare, F., E-mail: frederic.lamare@chu-bordeaux.fr; Fernandez, P. [Univ. Bordeaux, INCIA, UMR 5287, F-33400 Talence (France); CNRS, INCIA, UMR 5287, F-33400 Talence (France); Service de Médecine Nucléaire, Hôpital Pellegrin, CHU de Bordeaux, 33076 Bordeaux (France); Le Maitre, A.; Visvikis, D. [INSERM, UMR1101, LaTIM, Université de Bretagne Occidentale, 29609 Brest (France); Dawood, M.; Schäfers, K. P. [European Institute for Molecular Imaging, University of Münster, Mendelstr. 11, 48149 Münster (Germany); Rimoldi, O. E. [Vita-Salute University and Scientific Institute San Raffaele, Milan, Italy and CNR Istituto di Bioimmagini e Fisiologia Molecolare, Milan (Italy)

    2014-07-15

    Purpose: Cardiac imaging suffers from both respiratory and cardiac motion. One of the proposed solutions involves double gated acquisitions. Although such an approach may lead to both respiratory and cardiac motion compensation there are issues associated with (a) the combination of data from cardiac and respiratory motion bins, and (b) poor statistical quality images as a result of using only part of the acquired data. The main objective of this work was to evaluate different schemes of combining binned data in order to identify the best strategy to reconstruct motion free cardiac images from dual gated positron emission tomography (PET) acquisitions. Methods: A digital phantom study as well as seven human studies were used in this evaluation. PET data were acquired in list mode (LM). A real-time position management system and an electrocardiogram device were used to provide the respiratory and cardiac motion triggers registered within the LM file. Acquired data were subsequently binned considering four and six cardiac gates, or the diastole only in combination with eight respiratory amplitude gates. PET images were corrected for attenuation, but no randoms nor scatter corrections were included. Reconstructed images from each of the bins considered above were subsequently used in combination with an affine or an elastic registration algorithm to derive transformation parameters allowing the combination of all acquired data in a particular position in the cardiac and respiratory cycles. Images were assessed in terms of signal-to-noise ratio (SNR), contrast, image profile, coefficient-of-variation (COV), and relative difference of the recovered activity concentration. Results: Regardless of the considered motion compensation strategy, the nonrigid motion model performed better than the affine model, leading to higher SNR and contrast combined with a lower COV. Nevertheless, when compensating for respiration only, no statistically significant differences were

  9. Dual cardiac-respiratory gated PET: implementation and results from a feasibility study

    International Nuclear Information System (INIS)

    Martinez-Moeller, Axel; Zikic, Darko; Navab, Nassir; Botnar, Rene M.; Bundschuh, Ralph A.; Ziegler, Sibylle I.; Schwaiger, Markus; Nekolla, Stephan G.; Howe, William

    2007-01-01

    Spatial resolution in myocardial imaging is impaired by both cardiac and respiratory motion owing to motional blurring. We investigated the feasibility of a dual cardiac-respiratory gated positron emission tomography (PET) acquisition using a clinical PET/computer tomography (CT) scanner. We describe its implementation and present results on the respiratory motion observed. The correlation between diaphragmatic excursion measured by real-time magnetic resonance imaging (MRI) and the expansion of the chest measured with an elastic belt was studied in six subjects. PET list mode acquisitions were then performed in 12 patients, six of them injected with 13 N-ammonia and six with 18 F-FDG. In parallel, the ECG and respiratory signals of the patients were recorded and the list mode file correspondingly sorted using a dual gated approach. Respiratory motion of the heart was quantified by measuring the displacement between the inspiratory and expiratory images in the diastolic phase by means of intensity-based non-rigid image registration. The correlation between diaphragmatic excursion and expansion of the chest was excellent (R 2 = 0.91), validating the ability of the elastic belt to provide an adequate respiratory trigger. Respiratory signals corresponding to the chest expansion showed a large inter-patient variability, requiring adapted algorithms in order to define suitable respiratory gates. Dual gated PET series were successfully acquired for both groups of patients, showing better resolved myocardial walls. The average respiratory motion of the heart measured by PET was 4.8 mm, with its largest component in the craniocaudal direction. Moreover, a deformation of the heart with respiration was observed, with the inferior wall moving significantly more than the anterior. Dual gated cardiac PET studies were performed successfully and showed better resolved myocardial walls as compared with ungated acquisitions. The respiratory motion of the heart presented a

  10. Calculation of left ventricular volumes and ejection fraction from dynamic cardiac-gated 15O-water PET/CT: 5D-PET.

    Science.gov (United States)

    Nordström, Jonny; Kero, Tanja; Harms, Hendrik Johannes; Widström, Charles; Flachskampf, Frank A; Sörensen, Jens; Lubberink, Mark

    2017-11-14

    Quantitative measurement of myocardial blood flow (MBF) is of increasing interest in the clinical assessment of patients with suspected coronary artery disease (CAD). 15 O-water positron emission tomography (PET) is considered the gold standard for non-invasive MBF measurements. However, calculation of left ventricular (LV) volumes and ejection fraction (EF) is not possible from standard 15 O-water uptake images. The purpose of the present work was to investigate the possibility of calculating LV volumes and LVEF from cardiac-gated parametric blood volume (V B ) 15 O-water images and from first pass (FP) images. Sixteen patients with mitral or aortic regurgitation underwent an eight-gate dynamic cardiac-gated 15 O-water PET/CT scan and cardiac MRI. V B and FP images were generated for each gate. Calculations of end-systolic volume (ESV), end-diastolic volume (EDV), stroke volume (SV) and LVEF were performed with automatic segmentation of V B and FP images, using commercially available software. LV volumes and LVEF were calculated with surface-, count-, and volume-based methods, and the results were compared with gold standard MRI. Using V B images, high correlations between PET and MRI ESV (r = 0.89, p  0.86, p dynamic 15 O-water PET is feasible and shows good correlation with MRI. However, the analysis method is laborious, and future work is needed for more automation to make the method more easily applicable in a clinical setting.

  11. Calculation of left ventricular volumes and ejection fraction from dynamic cardiac-gated 15O-water PET/CT: 5D-PET

    Directory of Open Access Journals (Sweden)

    Jonny Nordström

    2017-11-01

    Full Text Available Abstract Background Quantitative measurement of myocardial blood flow (MBF is of increasing interest in the clinical assessment of patients with suspected coronary artery disease (CAD. 15O-water positron emission tomography (PET is considered the gold standard for non-invasive MBF measurements. However, calculation of left ventricular (LV volumes and ejection fraction (EF is not possible from standard 15O-water uptake images. The purpose of the present work was to investigate the possibility of calculating LV volumes and LVEF from cardiac-gated parametric blood volume (V B 15O-water images and from first pass (FP images. Sixteen patients with mitral or aortic regurgitation underwent an eight-gate dynamic cardiac-gated 15O-water PET/CT scan and cardiac MRI. V B and FP images were generated for each gate. Calculations of end-systolic volume (ESV, end-diastolic volume (EDV, stroke volume (SV and LVEF were performed with automatic segmentation of V B and FP images, using commercially available software. LV volumes and LVEF were calculated with surface-, count-, and volume-based methods, and the results were compared with gold standard MRI. Results Using V B images, high correlations between PET and MRI ESV (r = 0.89, p  0.86, p < 0.001. Conclusion Calculation of LV volumes and LVEF from dynamic 15O-water PET is feasible and shows good correlation with MRI. However, the analysis method is laborious, and future work is needed for more automation to make the method more easily applicable in a clinical setting.

  12. Respiratory gating of cardiac PET data in list-mode acquisition

    International Nuclear Information System (INIS)

    Livieratos, Lefteris; Rajappan, Kim; Camici, Paolo G.; Stegger, Lars; Schafers, Klaus; Bailey, Dale L.

    2006-01-01

    Respiratory motion has been identified as a source of artefacts in most medical imaging modalities. This paper reports on respiratory gating as a means to eliminate motion-related inaccuracies in PET imaging. Respiratory gating was implemented in list mode with physiological signal recorded every millisecond together with the PET data. Respiration was monitored with an inductive respiration monitor using an elasticised belt around the patient's chest. Simultaneous ECG gating can be maintained independently by encoding ECG trigger signal into the list-mode data. Respiratory gating is performed in an off-line workstation with gating parameters defined retrospectively. The technique was applied on a preliminary set of patient data with C 15 O. Motion was visually observed in the cine displays of the sagittal and coronal views of the reconstructed respiratory gated images. Significant changes in the cranial-caudal position of the heart could be observed. The centroid of the cardiac blood pool showed an excursion of 4.5-16.5 mm (mean 8.5±4.8 mm) in the cranial-caudal direction, with more limited excursion of 1.1-7.0 mm (mean 2.5±2.2 mm) in the horizontal direction and 1.3-3.7 mm (mean 2.4±0.9 mm) in the vertical direction. These preliminary data show that the extent of motion involved in respiration is comparable to myocardial wall thickness, and respiratory gating may be considered in order to reduce this effect in the reconstructed images. (orig.)

  13. Respiratory gating of cardiac PET data in list-mode acquisition.

    Science.gov (United States)

    Livieratos, Lefteris; Rajappan, Kim; Stegger, Lars; Schafers, Klaus; Bailey, Dale L; Camici, Paolo G

    2006-05-01

    Respiratory motion has been identified as a source of artefacts in most medical imaging modalities. This paper reports on respiratory gating as a means to eliminate motion-related inaccuracies in PET imaging. Respiratory gating was implemented in list mode with physiological signal recorded every millisecond together with the PET data. Respiration was monitored with an inductive respiration monitor using an elasticised belt around the patient's chest. Simultaneous ECG gating can be maintained independently by encoding ECG trigger signal into the list-mode data. Respiratory gating is performed in an off-line workstation with gating parameters defined retrospectively. The technique was applied on a preliminary set of patient data with C(15)O. Motion was visually observed in the cine displays of the sagittal and coronal views of the reconstructed respiratory gated images. Significant changes in the cranial-caudal position of the heart could be observed. The centroid of the cardiac blood pool showed an excursion of 4.5-16.5 mm (mean 8.5+/-4.8 mm) in the cranial-caudal direction, with more limited excursion of 1.1-7.0 mm (mean 2.5+/-2.2 mm) in the horizontal direction and 1.3-3.7 mm (mean 2.4+/-0.9 mm) in the vertical direction. These preliminary data show that the extent of motion involved in respiration is comparable to myocardial wall thickness, and respiratory gating may be considered in order to reduce this effect in the reconstructed images.

  14. Multimodal Registration of gated cardiac PET, CT and MR sequences

    International Nuclear Information System (INIS)

    Baty, X.

    2007-07-01

    The research described in this manuscript deals with the multimodal registration of cardiac images from Magnetic Resonance Imaging (MRI), Position Emission Tomography (PET) and Computerized Tomography (CT). All these modalities are gated to the Electrocardiogram (ECG) and provide information to evaluate cardiac function, and to diagnose and to follow-up cardiovascular pathologies. PET imaging allows the evaluation of ventricular function and MRI is a gold standard for the study of the left ventricular function. The goal of our registration process is to merge functional (from PET) and anatomical images (from CT and MRI). Our process is adapted to the modalities used and is divided in two steps: (i) a global rigid 3-dimensional model-based ICP (Iterative Closest Point) registration between CT and MR data and (ii) an iconic 2-dimensional registration based on Free Form Deformations and Mutual Information. This last step presents an original contribution by using a composite image of CT (which presents epicardic contours) and PET (where endocardic contours are partially visible) data to make mutual information more accurate in representing the similarity with the MR data. To speed up the whole process, we also present a transformation initialization scheme using displacement field obtained form MR data only. The obtained results have been evaluated by experts. (author)

  15. Cardiac-gated parametric images from 82 Rb PET from dynamic frames and direct 4D reconstruction.

    Science.gov (United States)

    Germino, Mary; Carson, Richard E

    2018-02-01

    Cardiac perfusion PET data can be reconstructed as a dynamic sequence and kinetic modeling performed to quantify myocardial blood flow, or reconstructed as static gated images to quantify function. Parametric images from dynamic PET are conventionally not gated, to allow use of all events with lower noise. An alternative method for dynamic PET is to incorporate the kinetic model into the reconstruction algorithm itself, bypassing the generation of a time series of emission images and directly producing parametric images. So-called "direct reconstruction" can produce parametric images with lower noise than the conventional method because the noise distribution is more easily modeled in projection space than in image space. In this work, we develop direct reconstruction of cardiac-gated parametric images for 82 Rb PET with an extension of the Parametric Motion compensation OSEM List mode Algorithm for Resolution-recovery reconstruction for the one tissue model (PMOLAR-1T). PMOLAR-1T was extended to accommodate model terms to account for spillover from the left and right ventricles into the myocardium. The algorithm was evaluated on a 4D simulated 82 Rb dataset, including a perfusion defect, as well as a human 82 Rb list mode acquisition. The simulated list mode was subsampled into replicates, each with counts comparable to one gate of a gated acquisition. Parametric images were produced by the indirect (separate reconstructions and modeling) and direct methods for each of eight low-count and eight normal-count replicates of the simulated data, and each of eight cardiac gates for the human data. For the direct method, two initialization schemes were tested: uniform initialization, and initialization with the filtered iteration 1 result of the indirect method. For the human dataset, event-by-event respiratory motion compensation was included. The indirect and direct methods were compared for the simulated dataset in terms of bias and coefficient of variation as a

  16. Simultaneous ECG-gated PET imaging of multiple mice

    International Nuclear Information System (INIS)

    Seidel, Jurgen; Bernardo, Marcelino L.; Wong, Karen J.; Xu, Biying; Williams, Mark R.; Kuo, Frank; Jagoda, Elaine M.; Basuli, Falguni; Li, Changhui; Griffiths, Gary L.

    2014-01-01

    Introduction: We describe and illustrate a method for creating ECG-gated PET images of the heart for each of several mice imaged at the same time. The method is intended to increase “throughput” in PET research studies of cardiac dynamics or to obtain information derived from such studies, e.g. tracer concentration in end-diastolic left ventricular blood. Methods: An imaging bed with provisions for warming, anesthetic delivery, etc., was fabricated by 3D printing to allow simultaneous PET imaging of two side-by-side mice. After electrode attachment, tracer injection and placement of the animals in the scanner field of view, ECG signals from each animal were continuously analyzed and independent trigger markers generated whenever an R-wave was detected in each signal. PET image data were acquired in “list” mode and these trigger markers were inserted into this list along with the image data. Since each mouse is in a different spatial location in the FOV, sorting of these data using trigger markers first from one animal and then the other yields two independent and correctly formed ECG-gated image sequences that reflect the dynamical properties of the heart during an “average” cardiac cycle. Results: The described method yields two independent ECG-gated image sequences that exhibit the expected properties in each animal, e.g. variation of the ventricular cavity volumes from maximum to minimum and back during the cardiac cycle in the processed animal with little or no variation in these volumes during the cardiac cycle in the unprocessed animal. Conclusion: ECG-gated image sequences for each of several animals can be created from a single list mode data collection using the described method. In principle, this method can be extended to more than two mice (or other animals) and to other forms of physiological gating, e.g. respiratory gating, when several subjects are imaged at the same time

  17. Erroneous cardiac ECG-gated PET list-mode trigger events can be retrospectively identified and replaced by an offline reprocessing approach: first results in rodents

    International Nuclear Information System (INIS)

    Böning, Guido; Todica, Andrei; Vai, Alessandro; Lehner, Sebastian; Xiong, Guoming; Mille, Erik; Ilhan, Harun; Fougère, Christian la; Bartenstein, Peter; Hacker, Marcus

    2013-01-01

    The assessment of left ventricular function, wall motion and myocardial viability using electrocardiogram (ECG)-gated [ 18 F]-FDG positron emission tomography (PET) is widely accepted in human and in preclinical small animal studies. The nonterminal and noninvasive approach permits repeated in vivo evaluations of the same animal, facilitating the assessment of temporal changes in disease or therapy response. Although well established, gated small animal PET studies can contain erroneous gating information, which may yield to blurred images and false estimation of functional parameters. In this work, we present quantitative and visual quality control (QC) methods to evaluate the accuracy of trigger events in PET list-mode and physiological data. Left ventricular functional analysis is performed to quantify the effect of gating errors on the end-systolic and end-diastolic volumes, and on the ejection fraction (EF). We aim to recover the cardiac functional parameters by the application of the commonly established heart rate filter approach using fixed ranges based on a standardized population. In addition, we propose a fully reprocessing approach which retrospectively replaces the gating information of the PET list-mode file with appropriate list-mode decoding and encoding software. The signal of a simultaneously acquired ECG is processed using standard MATLAB vector functions, which can be individually adapted to reliably detect the R-peaks. Finally, the new trigger events are inserted into the PET list-mode file. A population of 30 mice with various health statuses was analyzed and standard cardiac parameters such as mean heart rate (119 ms ± 11.8 ms) and mean heart rate variability (1.7 ms ± 3.4 ms) derived. These standard parameter ranges were taken into account in the QC methods to select a group of nine optimal gated and a group of eight sub-optimal gated [ 18 F]-FDG PET scans of mice from our archive. From the list-mode files of the optimal gated group

  18. Strategies to reduce radiation dose in cardiac PET/CT

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Tung Hsin; Wu, Nien-Yun [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan (China); Wang, Shyh-Jen [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan (China); Department of Nuclear Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (China); Wu, Jay [Institute of Radiological science, Central Taiwan University of Science and Technology, Taichung, Taiwan (China); Mok, Greta S.P. [Department of Electrical and Electronics Engineering, Faculty of Science and Technology, University of Macau, Macau (China); Yang, Ching-Ching, E-mail: g39220003@yahoo.com.tw [Department of Radiological Technology, Tzu Chi College of Technology, 880, Sec.2, Chien-kuo Rd. Hualien 970, Taiwan (China); Huang, Tzung-Chi, E-mail: tzungchi.huang@mail.cmu.edu.tw [Department of Biomedical Imaging and Radiological Science, China Medical University, No.91 Hsueh-Shih Road, Taichung 40402, Taiwan (China)

    2011-08-21

    Background: Our aim was to investigate CT dose reduction strategies on a hybrid PET/CT scanner for cardiac applications. Materials: Image quality and dose estimation of different CT scanning protocols for CT coronary angiography (CTCA), and CT-based attenuation correction for PET imaging were investigated. Fifteen patients underwent CTCA, perfusion PET imaging at rest and under stress, and FDG PET for myocardial viability. These patients were divided into three groups based on the CTCA technique performed: retrospectively gated helical (RGH), ECG tube current modulation (ETCM), and prospective gated axial (PGA) acquisitions. All emission images were corrected for photon attenuation using CT images obtained by default setting and an ultra-low dose CT (ULDCT) scan. Results: Radiation dose in RGH technique was 22.2{+-}4.0 mSv. It was reduced to 10.95{+-}0.82 and 4.13{+-}0.31 mSv using ETCM and PGA techniques, respectively. Radiation dose in CT transmission scan was reduced by 96.5% (from 4.53{+-}0.5 to 0.16{+-}0.01 mSv) when applying ULDCT as compared to the default CT. No significant difference in terms of image quality was found among various protocols. Conclusion: The proposed CT scanning strategies, i.e. ETCM or PGA for CTCA and ULDCT for PET attenuation correction, could reduce radiation dose up to 47% without degrading imaging quality in an integrated cardiac PET/CT coronary artery examination.

  19. Cardiac gated ventilation

    International Nuclear Information System (INIS)

    Hanson, C.W. III; Hoffman, E.A.

    1995-01-01

    There are several theoretic advantages to synchronizing positive pressure breaths with the cardiac cycle, including the potential for improving distribution of pulmonary and myocardial blood flow and enhancing cardiac output. The authors evaluated the effects of synchronizing respiration to the cardiac cycle using a programmable ventilator and electron beam CT (EBCT) scanning. The hearts of anesthetized dogs were imaged during cardiac gated respiration with a 50 msec scan aperture. Multi slice, short axis, dynamic image data sets spanning the apex to base of the left ventricle were evaluated to determine the volume of the left ventricular chamber at end-diastole and end-systole during apnea, systolic and diastolic cardiac gating. The authors observed an increase in cardiac output of up to 30% with inspiration gated to the systolic phase of the cardiac cycle in a non-failing model of the heart

  20. Gated listmode acquisition with the QuadHIDAC animal PET to image mouse hearts

    International Nuclear Information System (INIS)

    Schaefers, K.P.; Lang, N.; Stegger, L.; Schober, O.; Schaefers, M.

    2006-01-01

    Purpose: the aim of this study was to develop ECG and respiratory gating in combination with listmode acquisition for the quadHIDAC small-animal PET scanner. Methods: ECG and respiratory gating was realized with the help of an external trigger device (BioVET) synchronized with the listmode acquisition. Listmode data of a mouse acquisition (injected with 6.5 MBq of 18 F-FDG) were sorted according to three different gating definitions: 12 cardiac gates, 8 respiratory gates and a combination of 8 cardiac and 8 respiratory gates. Images were reconstructed with filtered back-projection (ramp filter), and parameters like left ventricular wall thickness (WT), wall-to-wall separation (WS) and blood to myocardium activity ratios (BMR) were calculated. Results: cardiac gated images show improvement of all parameters (WT 2.6 mm, WS 4.1 mm, BRM 2.3) in diastole compared to ungated images (WT 3.0 mm, WS 3.4 mm, BMR 1.3). Respiratory gating had little effect on calculated parameters. Conclusion: ECG gating with the quadHIDAC can improve myocardial image quality in mice. This could have a major impact on the calculation of an image-derived input function for kinetic modelling. (orig.)

  1. Enhancing ejection fraction measurement through 4D respiratory motion compensation in cardiac PET imaging

    Science.gov (United States)

    Tang, Jing; Wang, Xinhui; Gao, Xiangzhen; Segars, W. Paul; Lodge, Martin A.; Rahmim, Arman

    2017-06-01

    ECG gated cardiac PET imaging measures functional parameters such as left ventricle (LV) ejection fraction (EF), providing diagnostic and prognostic information for management of patients with coronary artery disease (CAD). Respiratory motion degrades spatial resolution and affects the accuracy in measuring the LV volumes for EF calculation. The goal of this study is to systematically investigate the effect of respiratory motion correction on the estimation of end-diastolic volume (EDV), end-systolic volume (ESV), and EF, especially on the separation of normal and abnormal EFs. We developed a respiratory motion incorporated 4D PET image reconstruction technique which uses all gated-frame data to acquire a motion-suppressed image. Using the standard XCAT phantom and two individual-specific volunteer XCAT phantoms, we simulated dual-gated myocardial perfusion imaging data for normally and abnormally beating hearts. With and without respiratory motion correction, we measured the EDV, ESV, and EF from the cardiac-gated reconstructed images. For all the phantoms, the estimated volumes increased and the biases significantly reduced with motion correction compared with those without. Furthermore, the improvement of ESV measurement in the abnormally beating heart led to better separation of normal and abnormal EFs. The simulation study demonstrated the significant effect of respiratory motion correction on cardiac imaging data with motion amplitude as small as 0.7 cm. The larger the motion amplitude the more improvement respiratory motion correction brought about on the EF measurement. Using data-driven respiratory gating, we also demonstrated the effect of respiratory motion correction on estimating the above functional parameters from list mode patient data. Respiratory motion correction has been shown to improve the accuracy of EF measurement in clinical cardiac PET imaging.

  2. Comparison of volumetric and functional parameters in simultaneous cardiac PET/MR: feasibility of volumetric assessment with residual activity from prior PET/CT

    Energy Technology Data Exchange (ETDEWEB)

    Luecke, C.; Brenneis, B.; Grothoff, M.; Gutberlet, M. [University Leipzig - Heart Center, Department of Diagnostic and Interventional Radiology, Leipzig (Germany); Oppolzer, B.; Werner, P.; Jochimsen, T.; Sattler, B.; Barthel, H.; Sabri, O. [University Hospital Leipzig, Department of Nuclear Medicine, Leipzig (Germany); Foldyna, B. [University Leipzig - Heart Center, Department of Diagnostic and Interventional Radiology, Leipzig (Germany); Massachusetts General Hospital - Harvard Medical School, Cardiac MR PET CT Program, Boston, MA (United States); Lurz, P. [University Leipzig - Heart Center, Clinic for Internal Medicine/Cardiology, Leipzig (Germany); Lehmkuhl, L. [Herz- und Gefaess-Klinik GmbH, Radiologische Klinik, Bad Neustadt (Germany)

    2017-12-15

    To compare cardiac left ventricular (LV) parameters in simultaneously acquired hybrid fluorine-18-fluorodeoxyglucose ([18F] FDG) positron emission tomography/magnetic resonance imaging (PET/MRI) in patients with residual tracer activity of upstream PET/CT. Twenty-nine patients (23 men, age 58±17 years) underwent cardiac PET/MRI either directly after a non-cardiac PET/CT with homogenous cardiac [18F] FDG uptake (n=20) or for viability assessment (n=9). Gated cardiac [18F] FDG PET and cine MR sequences were acquired simultaneously and evaluated blinded to the cross-imaging results. Image quality (IQ), end-diastolic (LVEDV), end-systolic volume (LVESV), ejection fraction (LVEF) and myocardial mass (LVMM) were measured. Pearson correlation and intraclass correlation coefficient (ICC), regression and a Bland-Altman analysis were assessed. Except LVMM, volumetric and functional LV parameters demonstrated high correlations (LVESV: r=0.97, LVEDV: r=0.95, LVEF: r=0.91, LVMM: r=0.87, each p<0.05), but wide limits of agreement (LOA) for LVEDV (-25.3-82.5ml); LVESV (-33.1-72.7ml); LVEF (-18.9-14.8%) and LVMM (-78.2-43.2g). Intra- and interobserver reliability were very high (ICC≥0.95) for all parameters, except for MR-LVEF (ICC=0.87). PET-IQ (0-3) was high (mean: 2.2±0.9) with significant influence on LVMM calculations only. In simultaneously acquired cardiac PET/MRI data, LVEDV, LVESV and LVEF show good agreement. However, the agreement seems to be limited if cardiac PET/MRI follows PET/CT and only the residual activity is used. (orig.)

  3. Dual respiratory and cardiac motion estimation in PET imaging: Methods design and quantitative evaluation.

    Science.gov (United States)

    Feng, Tao; Wang, Jizhe; Tsui, Benjamin M W

    2018-04-01

    The goal of this study was to develop and evaluate four post-reconstruction respiratory and cardiac (R&C) motion vector field (MVF) estimation methods for cardiac 4D PET data. In Method 1, the dual R&C motions were estimated directly from the dual R&C gated images. In Method 2, respiratory motion (RM) and cardiac motion (CM) were separately estimated from the respiratory gated only and cardiac gated only images. The effects of RM on CM estimation were modeled in Method 3 by applying an image-based RM correction on the cardiac gated images before CM estimation, the effects of CM on RM estimation were neglected. Method 4 iteratively models the mutual effects of RM and CM during dual R&C motion estimations. Realistic simulation data were generated for quantitative evaluation of four methods. Almost noise-free PET projection data were generated from the 4D XCAT phantom with realistic R&C MVF using Monte Carlo simulation. Poisson noise was added to the scaled projection data to generate additional datasets of two more different noise levels. All the projection data were reconstructed using a 4D image reconstruction method to obtain dual R&C gated images. The four dual R&C MVF estimation methods were applied to the dual R&C gated images and the accuracy of motion estimation was quantitatively evaluated using the root mean square error (RMSE) of the estimated MVFs. Results show that among the four estimation methods, Methods 2 performed the worst for noise-free case while Method 1 performed the worst for noisy cases in terms of quantitative accuracy of the estimated MVF. Methods 4 and 3 showed comparable results and achieved RMSE lower by up to 35% than that in Method 1 for noisy cases. In conclusion, we have developed and evaluated 4 different post-reconstruction R&C MVF estimation methods for use in 4D PET imaging. Comparison of the performance of four methods on simulated data indicates separate R&C estimation with modeling of RM before CM estimation (Method 3) to be

  4. Real-time system for respiratory-cardiac gating in positron tomography

    International Nuclear Information System (INIS)

    Klein, G.J.; Reutter, B.W.; Ho, M.H.; Huesman, R.H.; Reed, J.H.

    1998-01-01

    A Macintosh-based signal processing system has been developed to support simultaneous respiratory and cardiac gating on the ECAT EXACT HR PET scanner. Using the Lab-View real-time software environment, the system reads analog inputs from a pneumatic respiratory bellows and an EGG monitor to compute an appropriate histogram memory location for the PET data. Respiratory state is determined by the bellows signal amplitude; cardiac state is based on the time since the last R-wave. These two states are used in a 2D lookup table to determine a combined respiratory-cardiac state. A 4-bit address encoding the selected histogram is directed from the system to the ECAT scanner, which dynamically switches the destination of tomograph events as respiratory-cardiac state changes. to Test the switching efficiency of the combined Macintosh/ECAT system, a rotating emission phantom was built. Acquisitions with 25 msec states while the phantom was rotating at 240 rpm demonstrate the system could effectively stop motion at this rate, with approximately 5 msec switching time between states

  5. Late infectious endocarditis of surgical patch closure of atrial septal defects diagnosed by 18F-fluorodeoxyglucose gated cardiac computed tomography (18F-FDG-PET/CT): a case report.

    Science.gov (United States)

    Honnorat, Estelle; Seng, Piseth; Riberi, Alberto; Habib, Gilbert; Stein, Andreas

    2016-08-24

    In contrast to percutaneous atrial septal occluder device, surgical patch closure of atrial defects was known to be no infective endocarditis risk. We herein report the first case of late endocarditis of surgical patch closure of atrial septal defects occurred at 47-year after surgery. On September 2014, a 56-year-old immunocompetent French Caucasian man was admitted into the Emergency Department for 3-week history of headache, acute decrease of psychomotor performance and fever at 40 °C. The diagnosis has been evoked during his admission for the management of a brain abscess and confirmed using 18F-fluorodeoxyglucose gated cardiac computed tomography (18F-FDG-PET/CT). Bacterial cultures of surgical deep samples of brain abscess were positive for Streptococcus intermedius and Aggregatibacter aphrophilus as identified by the matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry and confirmed with 16S rRNA gene sequencing. The patient was treated by antibiotics for 8 weeks and surgical patch closure removal. In summary, late endocarditis on surgical patch and on percutaneous atrial septal occluder device of atrial septal defects is rare. Cardiac imaging by the 18F-fluorodeoxyglucose gated cardiac computed tomography (18F-FDG-PET/CT) could improve the diagnosis and care endocarditis on surgical patch closure of atrial septal defects while transthoracic and transesophageal echocardiography remained difficult to interpret.

  6. Self-gated fat-suppressed cardiac cine MRI.

    Science.gov (United States)

    Ingle, R Reeve; Santos, Juan M; Overall, William R; McConnell, Michael V; Hu, Bob S; Nishimura, Dwight G

    2015-05-01

    To develop a self-gated alternating repetition time balanced steady-state free precession (ATR-SSFP) pulse sequence for fat-suppressed cardiac cine imaging. Cardiac gating is computed retrospectively using acquired magnetic resonance self-gating data, enabling cine imaging without the need for electrocardiogram (ECG) gating. Modification of the slice-select rephasing gradients of an ATR-SSFP sequence enables the acquisition of a one-dimensional self-gating readout during the unused short repetition time (TR). Self-gating readouts are acquired during every TR of segmented, breath-held cardiac scans. A template-matching algorithm is designed to compute cardiac trigger points from the self-gating signals, and these trigger points are used for retrospective cine reconstruction. The proposed approach is compared with ECG-gated ATR-SSFP and balanced steady-state free precession in 10 volunteers and five patients. The difference of ECG and self-gating trigger times has a variability of 13 ± 11 ms (mean ± SD). Qualitative reviewer scoring and ranking indicate no statistically significant differences (P > 0.05) between self-gated and ECG-gated ATR-SSFP images. Quantitative blood-myocardial border sharpness is not significantly different among self-gated ATR-SSFP ( 0.61±0.15 mm -1), ECG-gated ATR-SSFP ( 0.61±0.15 mm -1), or conventional ECG-gated balanced steady-state free precession cine MRI ( 0.59±0.15 mm -1). The proposed self-gated ATR-SSFP sequence enables fat-suppressed cardiac cine imaging at 1.5 T without the need for ECG gating and without decreasing the imaging efficiency of ATR-SSFP. © 2014 Wiley Periodicals, Inc.

  7. Retrospective data-driven respiratory gating for PET/CT

    International Nuclear Information System (INIS)

    Schleyer, Paul J; O'Doherty, Michael J; Barrington, Sally F; Marsden, Paul K

    2009-01-01

    Respiratory motion can adversely affect both PET and CT acquisitions. Respiratory gating allows an acquisition to be divided into a series of motion-reduced bins according to the respiratory signal, which is typically hardware acquired. In order that the effects of motion can potentially be corrected for, we have developed a novel, automatic, data-driven gating method which retrospectively derives the respiratory signal from the acquired PET and CT data. PET data are acquired in listmode and analysed in sinogram space, and CT data are acquired in cine mode and analysed in image space. Spectral analysis is used to identify regions within the CT and PET data which are subject to respiratory motion, and the variation of counts within these regions is used to estimate the respiratory signal. Amplitude binning is then used to create motion-reduced PET and CT frames. The method was demonstrated with four patient datasets acquired on a 4-slice PET/CT system. To assess the accuracy of the data-derived respiratory signal, a hardware-based signal was acquired for comparison. Data-driven gating was successfully performed on PET and CT datasets for all four patients. Gated images demonstrated respiratory motion throughout the bin sequences for all PET and CT series, and image analysis and direct comparison of the traces derived from the data-driven method with the hardware-acquired traces indicated accurate recovery of the respiratory signal.

  8. Role of respiratory-gated PET/CT for pancreatic tumors: A preliminary result

    International Nuclear Information System (INIS)

    Kasuya, Takeo; Tateishi, Ukihide; Suzuki, Kazufumi; Daisaki, Hiromitsu; Nishiyama, Yuji; Hata, Masaharu; Inoue, Tomio

    2013-01-01

    Purpose: The aim of this study is to ascertain role of respiratory-gated PET/CT for accurate diagnosis of pancreatic tumors. Materials and methods: Prior to clinical study, the phantom study was performed to evaluate the impact of respiratory motion on lesion quantification. Twenty-two patients (mean age 65 years) with pancreatic tumors were enrolled. Pathological diagnoses by surgical specimens consisted of pancreatic cancer (n = 15) and benign intraductal papillary mucinous neoplasm (IPMN, n = 7). Whole-body scan of non-respiratory-gated PET/CT was performed at first, and subsequent respiratory-gated PET/CT for one bed position was performed. All PET/CT studies were performed prior to surgery. The SUV max obtained by non-respiratory-gated PET/CT and respiratory-gated PET/CT, and percent difference in SUVmax (%SUVmax) were compared. Results: The profile curve of 5 respiratory bin image was most similar to that of static image. The third bin of 5 respiratory bin image showed highest FWHM (24.0 mm) and FWTM (32.7 mm). The mean SUVmax of pancreatic cancer was similar to that of benign IPMN on non-respiratory-gated PET/CT (p = 0.05), whereas significant difference was found between two groups on respiratory-gated PET/CT (p = 0.016). The mean %SUV of pancreatic cancer was greater than that of benign IPMN (p < 0.0001). Identification of the primary tumor in pancreatic head (n = 13, 59%) was improved by using respiratory-gated PET/CT because of minimal affection of physiological accumulation in duodenum. Conclusion: Respiratory-gated PET/CT is a feasible technique for evaluation of pancreatic tumors and allows more accurate identification of pancreatic tumors compared with non-respiratory-gated PET/CT

  9. Issues in quantification of registered respiratory gated PET/CT in the lung

    Science.gov (United States)

    Cuplov, Vesna; Holman, Beverley F.; McClelland, Jamie; Modat, Marc; Hutton, Brian F.; Thielemans, Kris

    2018-01-01

    PET/CT quantification of lung tissue is limited by several difficulties: the lung density and local volume changes during respiration, the anatomical mismatch between PET and CT and the relative contributions of tissue, air and blood to the PET signal (the tissue fraction effect). Air fraction correction (AFC) has been shown to improve PET image quantification in the lungs. Methods to correct for the movement and anatomical mismatch involve respiratory gating and image registration techniques. While conventional registration methods only account for spatial mismatch, the Jacobian determinant of the deformable registration transformation field can be used to estimate local volume changes and could therefore potentially be used to correct (i.e. Jacobian Correction, JC) the PET signal for changes in concentration due to local volume changes. This work aims to investigate the relationship between variations in the lung due to respiration, specifically density, tracer concentration and local volume changes. In particular, we study the effect of AFC and JC on PET quantitation after registration of respiratory gated PET/CT patient data. Six patients suffering from lung cancer with solitary pulmonary nodules underwent 18 F-FDG PET/cine-CT. The PET data were gated into six respiratory gates using displacement gating based on a real-time position management (RPM) signal and reconstructed with matched gated CT. The PET tracer concentration and tissue density were extracted from registered gated PET and CT images before and after corrections (AFC or JC) and compared to the values from the reference images. Before correction, we observed a linear correlation between the PET tracer concentration values and density. Across all gates and patients, the maximum relative change in PET tracer concentration before (after) AFC was found to be 16.2% (4.1%) and the maximum relative change in tissue density and PET tracer concentration before (after) JC was found to be 17.1% (5.5%) and 16

  10. Dynamic and gated PET. Quantitative imaging of the heart revisited

    International Nuclear Information System (INIS)

    Nekolla, S.G.

    2005-01-01

    This short overview focuses on the basic implementation as well as applications of cardiac PET studies acquired in dynamic and ECG triggered modes. Both acquisition modes are well suited for quantitative analysis and the advantages of such an approach are discussed. An outlook on the measurement of respiratory triggered studies and the new challenges this data presents is provided. In the context of modern PET/CT tomographs with the combination of high sensitivity and morphologic resolution, the promise of list mode acquisition is investigated. The before mentioned acquisition modes are ideal candidates for this technology the utility of which in a clinical setting is briefly discussed. The retrospective generation of dynamic and gated image data (and any combinations) is greatly facilitated with this approach. Finally, a novel presentation mode for the wealth of quantitative information generated by these systems is presented. (orig.)

  11. Cardiac sympathetic neuronal imaging using PET

    International Nuclear Information System (INIS)

    Lautamaeki, Riikka; Tipre, Dnyanesh; Bengel, Frank M.

    2007-01-01

    Balance of the autonomic nervous system is essential for adequate cardiac performance, and alterations seem to play a key role in the development and progression of various cardiac diseases. PET imaging of the cardiac autonomic nervous system has advanced extensively in recent years, and multiple pre- and postsynaptic tracers have been introduced. The high spatial and temporal resolution of PET enables noninvasive quantification of neurophysiologic processes at the tissue level. Ligands for catecholamine receptors, along with radiolabeled catecholamines and catecholamine analogs, have been applied to determine involvement of sympathetic dysinnervation at different stages of heart diseases such as ischemia, heart failure, and arrhythmia. This review summarizes the recent findings in neurocardiological PET imaging. Experimental studies with several radioligands and clinical findings in cardiac dysautonomias are discussed. (orig.)

  12. Respiratory trace feature analysis for the prediction of respiratory-gated PET quantification

    Science.gov (United States)

    Wang, Shouyi; Bowen, Stephen R.; Chaovalitwongse, W. Art; Sandison, George A.; Grabowski, Thomas J.; Kinahan, Paul E.

    2014-02-01

    The benefits of respiratory gating in quantitative PET/CT vary tremendously between individual patients. Respiratory pattern is among many patient-specific characteristics that are thought to play an important role in gating-induced imaging improvements. However, the quantitative relationship between patient-specific characteristics of respiratory pattern and improvements in quantitative accuracy from respiratory-gated PET/CT has not been well established. If such a relationship could be estimated, then patient-specific respiratory patterns could be used to prospectively select appropriate motion compensation during image acquisition on a per-patient basis. This study was undertaken to develop a novel statistical model that predicts quantitative changes in PET/CT imaging due to respiratory gating. Free-breathing static FDG-PET images without gating and respiratory-gated FDG-PET images were collected from 22 lung and liver cancer patients on a PET/CT scanner. PET imaging quality was quantified with peak standardized uptake value (SUVpeak) over lesions of interest. Relative differences in SUVpeak between static and gated PET images were calculated to indicate quantitative imaging changes due to gating. A comprehensive multidimensional extraction of the morphological and statistical characteristics of respiratory patterns was conducted, resulting in 16 features that characterize representative patterns of a single respiratory trace. The six most informative features were subsequently extracted using a stepwise feature selection approach. The multiple-regression model was trained and tested based on a leave-one-subject-out cross-validation. The predicted quantitative improvements in PET imaging achieved an accuracy higher than 90% using a criterion with a dynamic error-tolerance range for SUVpeak values. The results of this study suggest that our prediction framework could be applied to determine which patients would likely benefit from respiratory motion compensation

  13. Respiratory trace feature analysis for the prediction of respiratory-gated PET quantification

    International Nuclear Information System (INIS)

    Wang, Shouyi; Chaovalitwongse, W Art; Bowen, Stephen R; Kinahan, Paul E; Sandison, George A; Grabowski, Thomas J

    2014-01-01

    The benefits of respiratory gating in quantitative PET/CT vary tremendously between individual patients. Respiratory pattern is among many patient-specific characteristics that are thought to play an important role in gating-induced imaging improvements. However, the quantitative relationship between patient-specific characteristics of respiratory pattern and improvements in quantitative accuracy from respiratory-gated PET/CT has not been well established. If such a relationship could be estimated, then patient-specific respiratory patterns could be used to prospectively select appropriate motion compensation during image acquisition on a per-patient basis. This study was undertaken to develop a novel statistical model that predicts quantitative changes in PET/CT imaging due to respiratory gating. Free-breathing static FDG-PET images without gating and respiratory-gated FDG-PET images were collected from 22 lung and liver cancer patients on a PET/CT scanner. PET imaging quality was quantified with peak standardized uptake value (SUV peak ) over lesions of interest. Relative differences in SUV peak between static and gated PET images were calculated to indicate quantitative imaging changes due to gating. A comprehensive multidimensional extraction of the morphological and statistical characteristics of respiratory patterns was conducted, resulting in 16 features that characterize representative patterns of a single respiratory trace. The six most informative features were subsequently extracted using a stepwise feature selection approach. The multiple-regression model was trained and tested based on a leave-one-subject-out cross-validation. The predicted quantitative improvements in PET imaging achieved an accuracy higher than 90% using a criterion with a dynamic error-tolerance range for SUV peak values. The results of this study suggest that our prediction framework could be applied to determine which patients would likely benefit from respiratory motion

  14. Implementation and application of simulation platform of PET based on GATE

    International Nuclear Information System (INIS)

    Zhang Bin; Zhao Shujun; Zhang Shixun; Liu Haojia

    2010-01-01

    Positron emission tomography (PET) is a tool for obtaining functional image in vivo and GATE is a dedicated software for PET/SPECT simulation based on Mentor Carlo Method. It encapsulates the Geant4 libraries to achieve a modular and provides a number of new characteristics. In practice, a simulation platform of PET has been builded employing GATE based on Ubuntu operating system, including many keys and skills in the process. We have exploited benchmark PET, a testing example in GATE, and implemented PET scanner simulation in the end. Through analyzing the simulation data, the result demonstrate that predictive goal has been reached. The work provides the foundation for investigating PET scanner and optimizing the algorithm of tomograph image reconstruction. (authors)

  15. Validation of a simultaneous PET/MR system model for PET simulation using GATE

    International Nuclear Information System (INIS)

    Monnier, Florian; Fayad, Hadi; Bert, Julien; Schmidt, Holger; Visvikis, Dimitris

    2015-01-01

    Simultaneous PET/MR acquisition shows promise in a range of applications. Simulation using GATE is an essential tool that allows obtaining the ground truth for such acquisitions and therefore helping in the development and the validation of innovative processing methods such as PET image reconstruction, attenuation correction and motion correction. The purpose of this work is to validate the GATE simulation of the Siemens Biograph mMR PET/MR system. A model of the Siemens Biograph mMR was developed. This model includes the geometry and spatial positioning of the crystals inside the scanner and the characteristics of the detection process. The accuracy of the model was tested by comparing, on a real physical phantom study, GATE simulated results to reconstructed PET images using measured results obtained from a Siemens Biograph mMR system. The same parameters such as the acquisition time and phantom position inside the scanner were fixed for our simulations. List-mode outputs were recovered in both cases and reconstructed using the OPL-EM algorithm. Several parameters were used to compare the two reconstructed images such as profile comparison, signal-to-noise ratio and activity contrast analysis. Finally patient acquired MR images were segmented and used for the simulation of corresponding PET images. The simulated and acquired sets of reconstructed phantom images showed close emission values in regions of interest with relative differences lower than 5%. The scatter fraction was within a <3% agreement. Close matching of profiles and contrast indices were obtained between simulated and corresponding acquired PET images. Our results indicate that the GATE developed Biograph mMR model is accurate in comparison to the real scanner performance and can be used for evaluating innovative processing methods for applications in clinical PET/MR protocols.

  16. Cardiac tumours: non invasive detection and assessment by gated cardiac blood pool radionuclide imaging

    International Nuclear Information System (INIS)

    Pitcher, D.; Wainwright, R.; Brennand-Roper, D.; Deverall, P.; Sowton, E.; Maisey, M.

    1980-01-01

    Four patients with cardiac tumours were investigated by gated cardiac blood pool radionuclide imaging and echocardiography. Contrast angiocardiography was performed in three of the cases. Two left atrial tumours were detected by all three techniques. In one of these cases echocardiography alone showed additional mitral valve stenosis, but isotope imaging indicated tumour size more accurately. A large septal mass was detected by all three methods. In this patient echocardiography showed evidence of left ventricular outflow obstruction, confirmed at cardiac catheterisation, but gated isotope imaging provided a more detailed assessment of the abnormal cardiac anatomy. In the fourth case gated isotope imaging detected a large right ventricular tumour which had not been identified by echocardiography. Gated cardiac blood pool isotope imaging is a complementary technique to echocardiography for the non-invasive detection and assessment of cardiac tumours. (author)

  17. Evaluation of attenuation correction in cardiac PET using PET/MR.

    Science.gov (United States)

    Lau, Jeffrey M C; Laforest, R; Sotoudeh, H; Nie, X; Sharma, S; McConathy, J; Novak, E; Priatna, A; Gropler, R J; Woodard, P K

    2017-06-01

    Simultaneous acquisition Positron emission tomography/magnetic resonance (PET/MR) is a new technology that has potential as a tool both in research and clinical diagnosis. However, cardiac PET acquisition has not yet been validated using MR imaging for attenuation correction (AC). The goal of this study is to evaluate the feasibility of PET imaging using a standard 2-point Dixon volume interpolated breathhold examination (VIBE) MR sequence for AC. Evaluation was performed in both phantom and patient data. A chest phantom containing heart, lungs, and a lesion insert was scanned by both PET/MR and PET/CT. In addition, 30 patients underwent whole-body 18 F-fluorodeoxyglucose PET/CT followed by simultaneous cardiac PET/MR. Phantom study showed 3% reduction of activity values in the myocardium due to the non-inclusion of the phased array coil in the AC. In patient scans, average standardized uptake values (SUVs) obtained by PET/CT and PET/MR showed no significant difference (n = 30, 4.6 ± 3.5 vs 4.7 ± 2.8, P = 0.47). There was excellent per patient correlation between the values acquired by PET/CT and PET/MR (R 2  = 0.97). Myocardial SUVs PET imaging using MR for AC shows excellent correlation with myocardial SUVs obtained by standard PET/CT imaging. The 2-point Dixon VIBE MR technique can be used for AC in simultaneous PET/MR data acquisition.

  18. External radioactive markers for PET data-driven respiratory gating in positron emission tomography.

    Science.gov (United States)

    Büther, Florian; Ernst, Iris; Hamill, James; Eich, Hans T; Schober, Otmar; Schäfers, Michael; Schäfers, Klaus P

    2013-04-01

    Respiratory gating is an established approach to overcoming respiration-induced image artefacts in PET. Of special interest in this respect are raw PET data-driven gating methods which do not require additional hardware to acquire respiratory signals during the scan. However, these methods rely heavily on the quality of the acquired PET data (statistical properties, data contrast, etc.). We therefore combined external radioactive markers with data-driven respiratory gating in PET/CT. The feasibility and accuracy of this approach was studied for [(18)F]FDG PET/CT imaging in patients with malignant liver and lung lesions. PET data from 30 patients with abdominal or thoracic [(18)F]FDG-positive lesions (primary tumours or metastases) were included in this prospective study. The patients underwent a 10-min list-mode PET scan with a single bed position following a standard clinical whole-body [(18)F]FDG PET/CT scan. During this scan, one to three radioactive point sources (either (22)Na or (18)F, 50-100 kBq) in a dedicated holder were attached the patient's abdomen. The list mode data acquired were retrospectively analysed for respiratory signals using established data-driven gating approaches and additionally by tracking the motion of the point sources in sinogram space. Gated reconstructions were examined qualitatively, in terms of the amount of respiratory displacement and in respect of changes in local image intensity in the gated images. The presence of the external markers did not affect whole-body PET/CT image quality. Tracking of the markers led to characteristic respiratory curves in all patients. Applying these curves for gated reconstructions resulted in images in which motion was well resolved. Quantitatively, the performance of the external marker-based approach was similar to that of the best intrinsic data-driven methods. Overall, the gain in measured tumour uptake from the nongated to the gated images indicating successful removal of respiratory motion

  19. A contactless approach for respiratory gating in PET using continuous-wave radar.

    Science.gov (United States)

    Ersepke, Thomas; Büther, Florian; Heß, Mirco; Schäfers, Klaus P

    2015-08-01

    Respiratory gating is commonly used to reduce motion artifacts in positron emission tomography (PET). Clinically established methods for respiratory gating in PET require contact to the patient or a direct optical line between the sensor and the patient's torso and time consuming preparation. In this work, a contactless method for capturing a respiratory signal during PET is presented based on continuous-wave radar. The proposed method relies on the principle of emitting an electromagnetic wave and detecting the phase shift of the reflected wave, modulated due to the respiratory movement of the patient's torso. A 24 GHz carrier frequency was chosen allowing wave propagation through plastic and clothing with high reflections at the skin surface. A detector module and signal processing algorithms were developed to extract a quantitative respiratory signal. The sensor was validated using a high precision linear table. During volunteer measurements and [(18)F] FDG PET scans, the radar sensor was positioned inside the scanner bore of a PET/computed tomography scanner. As reference, pressure belt (one volunteer), depth camera-based (two volunteers, two patients), and PET data-driven (six patients) signals were acquired simultaneously and the signal correlation was quantified. The developed system demonstrated a high measurement accuracy for movement detection within the submillimeter range. With the proposed method, small displacements of 25 μm could be detected, not considerably influenced by clothing or blankets. From the patient studies, the extracted respiratory radar signals revealed high correlation (Pearson correlation coefficient) to those derived from the external pressure belt and depth camera signals (r = 0.69-0.99) and moderate correlation to those of the internal data-driven signals (r = 0.53-0.70). In some cases, a cardiac signal could be visualized, due to the representation of the mechanical heart motion on the skin. Accurate respiratory signals were

  20. Improving the Spatial Alignment in PET/CT Using Amplitude-Based Respiration-Gated PET and Respiration-Triggered CT

    NARCIS (Netherlands)

    Vos, C.S. van der; Grootjans, W.; Osborne, D.R.; Meeuwis, A.P.; Hamill, J.J.; Acuff, S.; Geus-Oei, L.F. de; Visser, E.P.

    2015-01-01

    Respiratory motion during PET can cause inaccuracies in the quantification of radiotracer uptake, which negatively affects PET-guided radiotherapy planning. Quantitative accuracy can be improved by respiratory gating. However, additional miscalculation of standardized uptake value (SUV) in PET

  1. Diagnostic value of rest and stress gated 82Rb PET myocardial perfusion imaging using quantitative software

    International Nuclear Information System (INIS)

    Shi Hongcheng; Gu Yusen; Liu Wenguan; Zhu Weimin; Halkar, R.K.; Santana, C.A.; Feng Yusheng

    2008-01-01

    Objective: Gated myocardial perfusion imaging (MPI) is regularly performed using SPECT. More recently, gated 82 Rb MPI has been used to assess left ventricular myocardial perfusion and function with new generation PET scanners. The objective of this study was to evaluate the value of rest and stress gated 82 Rb PET myocardial perfusion imaging and to determine whether the quantitative technique in- creased the confidence level of the interpreters. Methods: Thirty-two patients underwent rest and adenosine stress gated 82 Pb PET MPI. Emory Cardiac Toolbox quantitative software was used for processing and inter-predation. Left ventricular ejection fraction (LVEF), end-diastolic, end-systolic and transient ischemia dilation ratio were automatically generated. Three interpreters (nuclear medicine doctors) independently reviewed the studies. Visual scoring (1-5 scales: excellent, good, unsure, poor, uninterpretable) was used to assess the overall quality of the gated images and the added confidence level of interpretation. Visual assessment of the LVEF was compared to the automatically generated LVEF. Comparison between the visual assessment and software generated was graded on a 1- 5 scales (helpful, probably helpful, unsure, probably not helpful, definitely not helpful). The analysed items were divided into two groups (favorable group and negative group). The percentage and 95% confidence intervals of each group were calculated. Results: A total of 192 gated studies were evaluated (64 gated x 3 interpreters ). The overall quality of the gated images was good [excellent 40.1% (77/192), good 43.2% (83/192), unsure 3.1% (6/192), poor 13.6% (26/192), uninterpretable 0]. The 95% confidence intervals of good and excellent quality range from 78.1% to 88.6%. The interpreter's agreed with the automated LVEF on 85.4% of the gated images [agree 76.6% (147/192), probably agree 8.8% (17/192), unsure 3.1% (6/192), probably disagree 8.8% (17/192), disagree 2.6% (5/192)]. And its 95

  2. Automatic extraction of myocardial mass and volumes using parametric images from dynamic nongated PET

    DEFF Research Database (Denmark)

    Harms, Hendrik Johannes; Hansson, Nils Henrik Stubkjær; Tolbod, Lars Poulsen

    2016-01-01

    Dynamic cardiac positron emission tomography (PET) is used to quantify molecular processes in vivo. However, measurements of left-ventricular (LV) mass and volumes require electrocardiogram (ECG)-gated PET data. The aim of this study was to explore the feasibility of measuring LV geometry using non......-gated dynamic cardiac PET. METHODS: Thirty-five patients with aortic-valve stenosis and 10 healthy controls (HC) underwent a 27-min 11C-acetate PET/CT scan and cardiac magnetic resonance imaging (CMR). HC were scanned twice to assess repeatability. Parametric images of uptake rate K1 and the blood pool were......LV and WT only and an overestimation for LVEF at lower values. Intra- and inter-observer correlations were >0.95 for all PET measurements. PET repeatability accuracy in HC was comparable to CMR. CONCLUSION: LV mass and volumes are accurately and automatically generated from dynamic 11C-acetate PET without...

  3. Dual gated PET/CT imaging of small targets of the heart: method description and testing with a dynamic heart phantom.

    Science.gov (United States)

    Kokki, Tommi; Sipilä, Hannu T; Teräs, Mika; Noponen, Tommi; Durand-Schaefer, Nicolas; Klén, Riku; Knuuti, Juhani

    2010-01-01

    In PET imaging respiratory and cardiac contraction motions interfere the imaging of heart. The aim was to develop and evaluate dual gating method for improving the detection of small targets of the heart. The method utilizes two independent triggers which are sent periodically into list mode data based on respiratory and ECG cycles. An algorithm for generating dual gated segments from list mode data was developed. The test measurements showed that rotational and axial movements of point source can be separated spatially to different segments with well-defined borders. The effect of dual gating on detection of small moving targets was tested with a moving heart phantom. Dual gated images showed 51% elimination (3.6 mm out of 7.0 mm) of contraction motion of hot spot (diameter 3 mm) and 70% elimination (14 mm out of 20 mm) of respiratory motion. Averaged activity value of hot spot increases by 89% when comparing to non-gated images. Patient study of suspected cardiac sarcoidosis shows sharper spatial myocardial uptake profile and improved detection of small myocardial structures such as papillary muscles. The dual gating method improves detection of small moving targets in a phantom and it is feasible in clinical situations.

  4. Data-driven gating in PET: Influence of respiratory signal noise on motion resolution.

    Science.gov (United States)

    Büther, Florian; Ernst, Iris; Frohwein, Lynn Johann; Pouw, Joost; Schäfers, Klaus Peter; Stegger, Lars

    2018-05-21

    Data-driven gating (DDG) approaches for positron emission tomography (PET) are interesting alternatives to conventional hardware-based gating methods. In DDG, the measured PET data themselves are utilized to calculate a respiratory signal, that is, subsequently used for gating purposes. The success of gating is then highly dependent on the statistical quality of the PET data. In this study, we investigate how this quality determines signal noise and thus motion resolution in clinical PET scans using a center-of-mass-based (COM) DDG approach, specifically with regard to motion management of target structures in future radiotherapy planning applications. PET list mode datasets acquired in one bed position of 19 different radiotherapy patients undergoing pretreatment [ 18 F]FDG PET/CT or [ 18 F]FDG PET/MRI were included into this retrospective study. All scans were performed over a region with organs (myocardium, kidneys) or tumor lesions of high tracer uptake and under free breathing. Aside from the original list mode data, datasets with progressively decreasing PET statistics were generated. From these, COM DDG signals were derived for subsequent amplitude-based gating of the original list mode file. The apparent respiratory shift d from end-expiration to end-inspiration was determined from the gated images and expressed as a function of signal-to-noise ratio SNR of the determined gating signals. This relation was tested against additional 25 [ 18 F]FDG PET/MRI list mode datasets where high-precision MR navigator-like respiratory signals were available as reference signal for respiratory gating of PET data, and data from a dedicated thorax phantom scan. All original 19 high-quality list mode datasets demonstrated the same behavior in terms of motion resolution when reducing the amount of list mode events for DDG signal generation. Ratios and directions of respiratory shifts between end-respiratory gates and the respective nongated image were constant over all

  5. FDG PET-CT findings of extra-thoracic sarcoid are associated with cardiac sarcoid: A rationale for using FGD PET-CT for cardiac sarcoid evaluation.

    Science.gov (United States)

    Patel, Darshan C; Gunasekaran, Senthil S; Goettl, Christopher; Sweiss, Nadera J; Lu, Yang

    2017-07-05

    This retrospective study investigates the relationship between cardiac and extra-thoracic sarcoid findings on FDG PET-CT using a 72-hour pretest high-fat, high-protein, and very low-carbohydrate (HFHPVLC) diet. A total of 196 consecutive FDG PET-CT scans with 72-hour HFHPVLC diet preparation were performed between December 2014 and December 2015 in known sarcoid patients. Of these scans, 5 were excluded for non-adherence to diet preparation or underlying cancer. Cardiac and extra-thoracic sarcoid lesions were categorized and measured for radiotracer uptake. A total of 188 patients had 191 eligible FDG PET/CT scans (3 follow-up scans), of which there were 20 (10%) positive, 6 indeterminate (3%), and 165 (86%) negative for CS. Among the 20 scans positive for CS, 8 (40%) had findings of both cardiac and extra-thoracic sarcoid. Our study shows that 40% of CS patients also have FDG PET-CT findings of extra-thoracic sarcoid. This makes an intriguing case for FDG PET-CT use with pretest diet prep over cardiac MRI (CMR) for cardiac sarcoid evaluation, given that CMR is likely to overlook these extra-thoracic sites of disease.

  6. A contactless approach for respiratory gating in PET using continuous-wave radar

    Energy Technology Data Exchange (ETDEWEB)

    Ersepke, Thomas, E-mail: Thomas.Ersepke@rub.de; Büther, Florian; Heß, Mirco [European Institute for Molecular Imaging, University of Münster, Münster 48149 (Germany); Schäfers, Klaus P. [European Institute for Molecular Imaging, University of Münster, Münster 48149, Germany and DFG EXC 1003, Cluster of Excellence ‘Cells in Motion,’ Münster 48149 (Germany)

    2015-08-15

    Purpose: Respiratory gating is commonly used to reduce motion artifacts in positron emission tomography (PET). Clinically established methods for respiratory gating in PET require contact to the patient or a direct optical line between the sensor and the patient’s torso and time consuming preparation. In this work, a contactless method for capturing a respiratory signal during PET is presented based on continuous-wave radar. Methods: The proposed method relies on the principle of emitting an electromagnetic wave and detecting the phase shift of the reflected wave, modulated due to the respiratory movement of the patient’s torso. A 24 GHz carrier frequency was chosen allowing wave propagation through plastic and clothing with high reflections at the skin surface. A detector module and signal processing algorithms were developed to extract a quantitative respiratory signal. The sensor was validated using a high precision linear table. During volunteer measurements and [{sup 18}F] FDG PET scans, the radar sensor was positioned inside the scanner bore of a PET/computed tomography scanner. As reference, pressure belt (one volunteer), depth camera-based (two volunteers, two patients), and PET data-driven (six patients) signals were acquired simultaneously and the signal correlation was quantified. Results: The developed system demonstrated a high measurement accuracy for movement detection within the submillimeter range. With the proposed method, small displacements of 25 μm could be detected, not considerably influenced by clothing or blankets. From the patient studies, the extracted respiratory radar signals revealed high correlation (Pearson correlation coefficient) to those derived from the external pressure belt and depth camera signals (r = 0.69–0.99) and moderate correlation to those of the internal data-driven signals (r = 0.53–0.70). In some cases, a cardiac signal could be visualized, due to the representation of the mechanical heart motion on the skin

  7. Deep-inspiration breath-hold PET/CT versus free breathing PET/CT and respiratory gating PET for reference. Evaluation in 95 patients with lung cancer

    International Nuclear Information System (INIS)

    Kawano, Tsuyoshi; Ohtake, Eiji; Inoue, Tomio

    2011-01-01

    The objective of this study was to define the factors that correlate with differences in maximum standardized uptake value (SUV max ) in deep-inspiration breath-hold (DIBH) and free breathing (FB) positron emission tomography (PET)/CT admixed with respiratory gating (RG) PET for reference. Patients (n=95) with pulmonary lesions were evaluated at one facility over 33 months. After undergoing whole-body PET/CT, a RG PET and FB PET/CT scans were obtained, followed by a DIBH PET/CT scan. All scans were recorded using a list-mode dynamic collection method with respiratory gating. The RG PET was reconstructed using phase gating without attenuation correction; the FB PET was reconstructed from the RG PET sinogram datasets with attenuation correction. Respiratory motion distance, breathing cycle speed, and waveform of RG PET were recorded. The SUV max of FB PET/CT and DIBH PET/CT were recorded: the percent difference in SUV max between the FB and DIBH scans was defined as the %BH-index. The %BH-index was significantly higher for lesions in the lower lung area than in the upper lung area. Respiratory motion distance was significantly higher in the lower lung area than in the upper lung area. A significant relationship was observed between the %BH-index and respiratory motion distance. Waveforms without steady end-expiration tended to show a high %BH-index. Significant inverse relationships were observed between %BH-index and cycle speed, and between respiratory motion distance and cycle speed. Decrease in SUV max of FB PET/CT was due to tumor size, distribution of lower lung, long respiratory movement at slow breathing cycle speeds, and respiratory waveforms without steady end-expiration. (author)

  8. Extension of a data-driven gating technique to 3D, whole body PET studies

    International Nuclear Information System (INIS)

    Schleyer, Paul J; O'Doherty, Michael J; Marsden, Paul K

    2011-01-01

    Respiratory gating can be used to separate a PET acquisition into a series of near motion-free bins. This is typically done using additional gating hardware; however, software-based methods can derive the respiratory signal from the acquired data itself. The aim of this work was to extend a data-driven respiratory gating method to acquire gated, 3D, whole body PET images of clinical patients. The existing method, previously demonstrated with 2D, single bed-position data, uses a spectral analysis to find regions in raw PET data which are subject to respiratory motion. The change in counts over time within these regions is then used to estimate the respiratory signal of the patient. In this work, the gating method was adapted to only accept lines of response from a reduced set of axial angles, and the respiratory frequency derived from the lung bed position was used to help identify the respiratory frequency in all other bed positions. As the respiratory signal does not identify the direction of motion, a registration-based technique was developed to align the direction for all bed positions. Data from 11 clinical FDG PET patients were acquired, and an optical respiratory monitor was used to provide a hardware-based signal for comparison. All data were gated using both the data-driven and hardware methods, and reconstructed. The centre of mass of manually defined regions on gated images was calculated, and the overall displacement was defined as the change in the centre of mass between the first and last gates. The mean displacement was 10.3 mm for the data-driven gated images and 9.1 mm for the hardware gated images. No significant difference was found between the two gating methods when comparing the displacement values. The adapted data-driven gating method was demonstrated to successfully produce respiratory gated, 3D, whole body, clinical PET acquisitions.

  9. Integrating respiratory-gated PET-based target volume delineation in liver SBRT planning, a pilot study

    International Nuclear Information System (INIS)

    Riou, Olivier; Thariat, Juliette; Serrano, Benjamin; Azria, David; Paulmier, Benoit; Villeneuve, Remy; Fenoglietto, Pascal; Artenie, Antonella; Ortholan, Cécile; Faraggi, Marc

    2014-01-01

    To assess the feasibility and benefit of integrating four-dimensional (4D) Positron Emission Tomography (PET) – computed tomography (CT) for liver stereotactic body radiation therapy (SBRT) planning. 8 patients with 14 metastases were accrued in the study. They all underwent a non-gated PET and a 4D PET centered on the liver. The same CT scan was used for attenuation correction, registration, and considered the planning CT for SBRT planning. Six PET phases were reconstructed for each 4D PET. By applying an individualized threshold to the 4D PET, a Biological Internal Target Volume (BITV) was generated for each lesion. A gated Planning Target Volume (PTVg) was created by adding 3 mm to account for set-up margins. This volume was compared to a manual Planning Target Volume (PTV) delineated with the help of a semi-automatic Biological Target Volume (BTV) obtained from the non-gated exam. A 5 mm radial and a 10 mm craniocaudal margins were applied to account for tumor motion and set-up margins to create the PTV. One undiagnosed liver metastasis was discovered thanks to the 4D PET. The semi-automatic BTV were significantly smaller than the BITV (p = 0.0031). However, after applying adapted margins, 4D PET allowed a statistically significant decrease in the PTVg as compared to the PTV (p = 0.0052). In comparison to non-gated PET, 4D PET may better define the respiratory movements of liver targets and improve SBRT planning for liver metastases. Furthermore, non respiratory-gated PET exams can both misdiagnose liver metastases and underestimate the real internal target volumes

  10. New cardiac cameras: single-photon emission CT and PET.

    Science.gov (United States)

    Slomka, Piotr J; Berman, Daniel S; Germano, Guido

    2014-07-01

    Nuclear cardiology instrumentation has evolved significantly in the recent years. Concerns about radiation dose and long acquisition times have propelled developments of dedicated high-efficiency cardiac SPECT scanners. Novel collimator designs, such as multipinhole or locally focusing collimators arranged in geometries that are optimized for cardiac imaging, have been implemented to enhance photon-detection sensitivity. Some of these new SPECT scanners use solid-state photon detectors instead of photomultipliers to improve image quality and to reduce the scanner footprint. These new SPECT devices allow dramatic up to 7-fold reduction in acquisition times or similar reduction in radiation dose. In addition, new hardware for photon attenuation correction allowing ultralow radiation doses has been offered by some vendors. To mitigate photon attenuation artifacts for the new SPECT scanners not equipped with attenuation correction hardware, 2-position (upright-supine or prone-supine) imaging has been proposed. PET hardware developments have been primarily driven by the requirements of oncologic imaging, but cardiac imaging can benefit from improved PET image quality and improved sensitivity of 3D systems. The time-of-flight reconstruction combined with resolution recovery techniques is now implemented by all major PET vendors. These new methods improve image contrast and image resolution and reduce image noise. High-sensitivity 3D PET without interplane septa allows reduced radiation dose for cardiac perfusion imaging. Simultaneous PET/MR hybrid system has been developed. Solid-state PET detectors with avalanche photodiodes or digital silicon photomultipliers have been introduced, and they offer improved imaging characteristics and reduced sensitivity to electromagnetic MR fields. Higher maximum count rate of the new PET detectors allows routine first-pass Rb-82 imaging, with 3D PET acquisition enabling clinical utilization of dynamic imaging with myocardial flow

  11. Demons versus level-set motion registration for coronary 18F-sodium fluoride PET

    Science.gov (United States)

    Rubeaux, Mathieu; Joshi, Nikhil; Dweck, Marc R.; Fletcher, Alison; Motwani, Manish; Thomson, Louise E.; Germano, Guido; Dey, Damini; Berman, Daniel S.; Newby, David E.; Slomka, Piotr J.

    2016-03-01

    Ruptured coronary atherosclerotic plaques commonly cause acute myocardial infarction. It has been recently shown that active microcalcification in the coronary arteries, one of the features that characterizes vulnerable plaques at risk of rupture, can be imaged using cardiac gated 18F-sodium fluoride (18F-NaF) PET. We have shown in previous work that a motion correction technique applied to cardiac-gated 18F-NaF PET images can enhance image quality and improve uptake estimates. In this study, we further investigated the applicability of different algorithms for registration of the coronary artery PET images. In particular, we aimed to compare demons vs. level-set nonlinear registration techniques applied for the correction of cardiac motion in coronary 18F-NaF PET. To this end, fifteen patients underwent 18F-NaF PET and prospective coronary CT angiography (CCTA). PET data were reconstructed in 10 ECG gated bins; subsequently these gated bins were registered using demons and level-set methods guided by the extracted coronary arteries from CCTA, to eliminate the effect of cardiac motion on PET images. Noise levels, target-to-background ratios (TBR) and global motion were compared to assess image quality. Compared to the reference standard of using only diastolic PET image (25% of the counts from PET acquisition), cardiac motion registration using either level-set or demons techniques almost halved image noise due to the use of counts from the full PET acquisition and increased TBR difference between 18F-NaF positive and negative lesions. The demons method produces smoother deformation fields, exhibiting no singularities (which reflects how physically plausible the registration deformation is), as compared to the level-set method, which presents between 4 and 8% of singularities, depending on the coronary artery considered. In conclusion, the demons method produces smoother motion fields as compared to the level-set method, with a motion that is physiologically

  12. Simulation of time curves in small animal PET using GATE

    International Nuclear Information System (INIS)

    Simon, Luc; Strul, Daniel; Santin, Giovanni; Krieguer, Magalie; Morel, Christian

    2004-01-01

    The ClearPET project of the Crystal Clear Collaboration (CCC) is building spin-off technology for high resolution small animal Positron Emission Tomography (PET). Monte Carlo simulation is essential for optimizing the specifications of these systems with regards to their most important characteristics, such as spatial resolution, sensitivity, or count rate performance. GATE, the Geant4 Application for Tomographic Emission simulates the passing of time during real acquisitions, allowing to handle dynamic systems such as decaying source distributions or moving detectors. GATE output is analyzed on an event-by-event basis. The time associated with each single event allows to sort coincidences and to model dead-time. This leads to the study of time curves for a prospective small animal PET scanner design. The count rates of true, and random coincidences are discussed together with the corresponding Noise Equivalent Count (NEC) rates as a function of some PET scanner specifications such as detector dead time, or coincidence time window

  13. An update on technical and methodological aspects for cardiac PET applications

    International Nuclear Information System (INIS)

    PRESOTTO, Luca; BUSNARDO, Elena; GIANOLLI, Luigi; BETTINARDI, Valentino

    2016-01-01

    Positron emission tomography (PET) is indicated for a large number of cardiac diseases: perfusion and viability studies are commonly used to evaluate coronary artery disease; PET can also be used to assess sarcoidosis and endocarditis, as well as to investigate amyloidosis. Furthermore, a hot topic for research is plaque characterization. Most of these studies are technically very challenging. High count rates and short acquisition times characterize perfusion scans while very small targets have to be imaged in inflammation/infection and plaques examinations. Furthermore, cardiac PET suffers from respiratory and cardiac motion blur. Each type of studies has specific requirements from the technical and methodological point of view, thus PET systems with overall high performances are required. Furthermore, in the era of hybrid PET/computed tomography (CT) and PET/Magnetic Resonance Imaging (MRI) systems, the combination of complementary functional and anatomical information can be used to improve diagnosis and prognosis. Moreover, PET images can be qualitatively and quantitatively improved exploiting information from the other modality, using advanced algorithms. In this review we will report the latest technological and methodological innovations for PET cardiac applications, with particular reference to the state of the art of the hybrid PET/CT and PET/MRI. We will also report the most recent advancements in software, from reconstruction algorithms to image processing and analysis programs.

  14. Evaluation of ECG-gated [(11)C]acetate PET for measuring left ventricular volumes, mass, and myocardial external efficiency.

    Science.gov (United States)

    Hansson, Nils Henrik; Tolbod, Lars; Harms, Johannes; Wiggers, Henrik; Kim, Won Yong; Hansen, Esben; Zaremba, Tomas; Frøkiær, Jørgen; Jakobsen, Steen; Sørensen, Jens

    2016-08-01

    Noninvasive estimation of myocardial external efficiency (MEE) requires measurements of left ventricular (LV) oxygen consumption with [(11)C]acetate PET in addition to LV stroke volume and mass with cardiovascular magnetic resonance (CMR). Measuring LV geometry directly from ECG-gated [(11)C]acetate PET might enable MEE evaluation from a single PET scan. Therefore, we sought to establish the accuracy of measuring LV volumes, mass, and MEE directly from ECG-gated [(11)C]acetate PET. Thirty-five subjects with aortic valve stenosis underwent ECG-gated [(11)C]acetate PET and CMR. List mode PET data were rebinned into 16-bin ECG-gated uptake images before measuring LV volumes and mass using commercial software and compared to CMR. Dynamic datasets were used for calculation of mean LV oxygen consumption and MEE. LV mass, volumes, and ejection fraction measured by CMR and PET correlated strongly (r = 0.86-0.92, P PET (P PET-based MEE, corrected for bias, correlated fairly with PET/CMR-based MEE (r = 0.60, P PET-based MEE bias was strongly associated with LV wall thickness. Although analysis-related improvements in accuracy are recommended, LV geometry estimated from ECG-gated [(11)C]acetate PET correlate excellently with CMR and can indeed be used to evaluate MEE.

  15. Measuring cardiac efficiency using PET/MRI

    International Nuclear Information System (INIS)

    Gullberg, Grand; Aparici, Carina Mari; Brooks, Gabriel; Liu, Jing; Guccione, Julius; Saloner, David; Seo, Adam Youngho; Ordovas, Karen Gomes

    2015-01-01

    Heart failure (HF) is a complex syndrome that is projected by the American Heart Association to cost $160 billion by 2030. In HF, significant metabolic changes and structural remodeling lead to reduced cardiac efficiency. A normal heart is approximately 20-25% efficient measured by the ratio of work to oxygen utilization (1 ml oxygen = 21 joules). The heart requires rapid production of ATP where there is complete turnover of ATP every 10 seconds with 90% of ATP produced by mitochondrial oxidative metabolism requiring substrates of approximately 30% glucose and 65% fatty acids. In our preclinical PET/MRI studies in normal rats, we showed a negative correlation between work and the influx rate constant for 18FDG, confirming that glucose is not the preferred substrate at rest. However, even though fatty acid provides 9 kcal/gram compared to 4 kcal/gram for glucose, in HF the preferred energy source is glucose. PET/MRI offers the potential to study this maladapted mechanism of metabolism by measuring work in a region of myocardial tissue simultaneously with the measure of oxygen utilization, glucose, and fatty acid metabolism and to study cardiac efficiency in the etiology of and therapies for HF. MRI is used to measure strain and a finite element mechanical model using pressure measurements is used to estimate myofiber stress. The integral of strain times stress provides a measure of work which divided by energy utilization, estimated by the production of 11CO2 from intravenous injection of 11C-acetate, provides a measure of cardiac efficiency. Our project involves translating our preclinical research to the clinical application of measuring cardiac efficiency in patients. Using PET/MRI to develop technologies for studying myocardial efficiency in patients, provides an opportunity to relate cardiac work of specific tissue regions to metabolic substrates, and measure the heterogeneity of LV efficiency.

  16. Measuring cardiac efficiency using PET/MRI

    Energy Technology Data Exchange (ETDEWEB)

    Gullberg, Grand [Lawrence Berkeley National Laboratory (United States); Aparici, Carina Mari; Brooks, Gabriel [University of California San Francisco (United States); Liu, Jing; Guccione, Julius; Saloner, David; Seo, Adam Youngho; Ordovas, Karen Gomes [Lawrence Berkeley National Laboratory (United States)

    2015-05-18

    Heart failure (HF) is a complex syndrome that is projected by the American Heart Association to cost $160 billion by 2030. In HF, significant metabolic changes and structural remodeling lead to reduced cardiac efficiency. A normal heart is approximately 20-25% efficient measured by the ratio of work to oxygen utilization (1 ml oxygen = 21 joules). The heart requires rapid production of ATP where there is complete turnover of ATP every 10 seconds with 90% of ATP produced by mitochondrial oxidative metabolism requiring substrates of approximately 30% glucose and 65% fatty acids. In our preclinical PET/MRI studies in normal rats, we showed a negative correlation between work and the influx rate constant for 18FDG, confirming that glucose is not the preferred substrate at rest. However, even though fatty acid provides 9 kcal/gram compared to 4 kcal/gram for glucose, in HF the preferred energy source is glucose. PET/MRI offers the potential to study this maladapted mechanism of metabolism by measuring work in a region of myocardial tissue simultaneously with the measure of oxygen utilization, glucose, and fatty acid metabolism and to study cardiac efficiency in the etiology of and therapies for HF. MRI is used to measure strain and a finite element mechanical model using pressure measurements is used to estimate myofiber stress. The integral of strain times stress provides a measure of work which divided by energy utilization, estimated by the production of 11CO2 from intravenous injection of 11C-acetate, provides a measure of cardiac efficiency. Our project involves translating our preclinical research to the clinical application of measuring cardiac efficiency in patients. Using PET/MRI to develop technologies for studying myocardial efficiency in patients, provides an opportunity to relate cardiac work of specific tissue regions to metabolic substrates, and measure the heterogeneity of LV efficiency.

  17. EANM/ESC guidelines for radionuclide imaging of cardiac function

    DEFF Research Database (Denmark)

    Hesse, B.; Lindhardt, T.B.; Acampa, W.

    2008-01-01

    radionuclide ventriculography, gated myocardial perfusion scintigraphy, gated PET, and studies with non-imaging devices for the evaluation of cardiac function. The items covered are presented in 11 sections: clinical indications, radiopharmaceuticals and dosimetry, study acquisition, RV EF, LV EF, LV volumes...

  18. Automatic extraction of left ventricular mass and volumes using parametric images from non-ECG-gated 15O-water PET/CT

    DEFF Research Database (Denmark)

    Nordström, J; Harms, Hans; Lubberink, Mark

    of the present study was to investigate the feasibility of measuring LV geometry using dynamic 15O-water PET/CT without ECG-gating. Methods: Parametric images of MBF, perfusable tissue fraction (PTF) and LV blood pool were generated automatically using kinetic modelling. Segmentation of the LV wall using PTF......Introduction: 15O-water positron emission tomography (PET) is considered the gold standard for non-invasive quantification of myocardial blood flow (MBF). It has been shown to identify patients with significant coronary artery disease (CAD) with high accuracy. Hypertrophy with or without dilatation...... combined to measure stroke volume (SV=EDV-ESV) and ejection fraction (EF=SV/EDV). Accuracy was determined by comparing PET to cardiac magnetic resonance (CMR) in 30 asymptomatic patients with high grade LV regurgitation (group A). Precision was determined as inter-observer variation in group...

  19. Fully automated intrinsic respiratory and cardiac gating for small animal CT

    Energy Technology Data Exchange (ETDEWEB)

    Kuntz, J; Baeuerle, T; Semmler, W; Bartling, S H [Department of Medical Physics in Radiology, German Cancer Research Center, Heidelberg (Germany); Dinkel, J [Department of Radiology, German Cancer Research Center, Heidelberg (Germany); Zwick, S [Department of Diagnostic Radiology, Medical Physics, Freiburg University (Germany); Grasruck, M [Siemens Healthcare, Forchheim (Germany); Kiessling, F [Chair of Experimental Molecular Imaging, RWTH-Aachen University, Medical Faculty, Aachen (Germany); Gupta, R [Department of Radiology, Massachusetts General Hospital, Boston, MA (United States)], E-mail: j.kuntz@dkfz.de

    2010-04-07

    A fully automated, intrinsic gating algorithm for small animal cone-beam CT is described and evaluated. A parameter representing the organ motion, derived from the raw projection images, is used for both cardiac and respiratory gating. The proposed algorithm makes it possible to reconstruct motion-corrected still images as well as to generate four-dimensional (4D) datasets representing the cardiac and pulmonary anatomy of free-breathing animals without the use of electrocardiogram (ECG) or respiratory sensors. Variation analysis of projections from several rotations is used to place a region of interest (ROI) on the diaphragm. The ROI is cranially extended to include the heart. The centre of mass (COM) variation within this ROI, the filtered frequency response and the local maxima are used to derive a binary motion-gating parameter for phase-sensitive gated reconstruction. This algorithm was implemented on a flat-panel-based cone-beam CT scanner and evaluated using a moving phantom and animal scans (seven rats and eight mice). Volumes were determined using a semiautomatic segmentation. In all cases robust gating signals could be obtained. The maximum volume error in phantom studies was less than 6%. By utilizing extrinsic gating via externally placed cardiac and respiratory sensors, the functional parameters (e.g. cardiac ejection fraction) and image quality were equivalent to this current gold standard. This algorithm obviates the necessity of both gating hardware and user interaction. The simplicity of the proposed algorithm enables adoption in a wide range of small animal cone-beam CT scanners.

  20. Simultaneous determination of dynamic cardiac metabolism and function using PET/MRI.

    Science.gov (United States)

    Barton, Gregory P; Vildberg, Lauren; Goss, Kara; Aggarwal, Niti; Eldridge, Marlowe; McMillan, Alan B

    2018-05-01

    Cardiac metabolic changes in heart disease precede overt contractile dysfunction. However, metabolism and function are not typically assessed together in clinical practice. The purpose of this study was to develop a cardiac positron emission tomography/magnetic resonance (PET/MR) stress test to assess the dynamic relationship between contractile function and metabolism in a preclinical model. Following an overnight fast, healthy pigs (45-50 kg) were anesthetized and mechanically ventilated. 18 F-fluorodeoxyglucose ( 18 F-FDG) solution was administered intravenously at a constant rate of 0.01 mL/s for 60 minutes. A cardiac PET/MR stress test was performed using normoxic gas (F I O 2  = .209) and hypoxic gas (F I O 2  = .12). Simultaneous cardiac imaging was performed on an integrated 3T PET/MR scanner. Hypoxic stress induced a significant increase in heart rate, cardiac output, left ventricular (LV) ejection fraction (EF), and peak torsion. There was a significant decline in arterial SpO 2 , LV end-diastolic and end-systolic volumes in hypoxia. Increased LV systolic function was coupled with an increase in myocardial FDG uptake (Ki) during hypoxic stress. PET/MR with continuous FDG infusion captures dynamic changes in both cardiac metabolism and contractile function. This technique warrants evaluation in human cardiac disease for assessment of subtle functional and metabolic abnormalities.

  1. Initial Experience With Simultaneous 18F-FDG PET/MRI in the Evaluation of Cardiac Sarcoidosis and Myocarditis.

    Science.gov (United States)

    Hanneman, Kate; Kadoch, Michael; Guo, Henry H; Jamali, Mehran; Quon, Andrew; Iagaru, Andrei; Herfkens, Robert

    2017-07-01

    The purpose of this study was to compare combined PET/MRI with PET/CT and cardiac MRI in the evaluation of cardiac sarcoidosis and myocarditis. Ten patients (4 men and 6 women; 56.1 ± 9.6 years old) were prospectively enrolled for evaluation of suspected cardiac sarcoidosis or myocarditis. Written informed consent was obtained. Following administration of 9.9 ± 0.9 mCi F-FDG, patients underwent standard cardiac PET/CT followed by combined PET/MRI using a simultaneous 3-T scanner. Cardiac MRI sequences included ECG-triggered cine SSFP, T2-weighted, and late gadolinium-enhanced imaging. Myocardial involvement was assessed with separate analysis of combined PET/MRI, PET/CT, and cardiac MRI data using dedicated postprocessing software. Estimates of radiation dose were derived from the applied doses of F-FDG and CT protocol parameters. Imaging was acquired with a delay from F-FDG injection of 90.2 ± 27.4 minutes for PET/CT and 207.7 ± 40.3 minutes for PET/MRI. Total scan time for PET/MRI was significantly longer than for PET/CT (81.4 ± 14.8 vs 12.0 minutes, P PET/MRI compared with PET/CT (6.9 ± 0.6 vs 8.2 ± 1.1 mSv, P = 0.007). There was no significant difference in the number of positive cases identified between combined PET/MRI (n = 10 [100%]), PET/CT (n = 6 [60%]), and cardiac MRI (n = 8 [80%]), P = 0.091. Simultaneous cardiac PET/MRI is feasible in the evaluation of cardiac sarcoidosis and myocarditis achieving diagnostic image quality.

  2. Spatiotemporal processing of gated cardiac SPECT images using deformable mesh modeling

    International Nuclear Information System (INIS)

    Brankov, Jovan G.; Yang Yongyi; Wernick, Miles N.

    2005-01-01

    In this paper we present a spatiotemporal processing approach, based on deformable mesh modeling, for noise reduction in gated cardiac single-photon emission computed tomography images. Because of the partial volume effect (PVE), clinical cardiac-gated perfusion images exhibit a phenomenon known as brightening--the myocardium appears to become brighter as the heart wall thickens. Although brightening is an artifact, it serves as an important diagnostic feature for assessment of wall thickening in clinical practice. Our proposed processing algorithm aims to preserve this important diagnostic feature while reducing the noise level in the images. The proposed algorithm is based on the use of a deformable mesh for modeling the cardiac motion in a gated cardiac sequence, based on which the images are processed by smoothing along space-time trajectories of object points while taking into account the PVE. Our experiments demonstrate that the proposed algorithm can yield significantly more-accurate results than several existing methods

  3. Estimation of organ motion for gated PET imaging in small animal using artificial tumor

    Energy Technology Data Exchange (ETDEWEB)

    Woo, Sang Keun; Yu, Jung Woo; Lee, Yong Jin [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2011-10-15

    The image quality is lowered by reducing of contrast and signal due to breathing and heart motion when acquire Positron Emission Tomography (PET) image of small animal tumor. Therefore motion correction is required for betterment of quantitative estimation of tumor. The gated PET using external monitoring device is commonly used for motion correction. But that method has limitation by reason of detection from the outside. Therefore, we had devised the in-vivo motion assessment. In-vivo motion has been demonstrated in lung, liver and abdomen region of rats by coated molecular sieve. In PET image analysis, count and SNR were drawn in the target region. The motion compensation PET image for optimal gate number was confirmed by FWHM. Artificial motion evaluation of tumor using molecular sieve suggests possibility of motion correction modeling without external monitoring devices because it estimates real internal motion of lung, liver, and abdomen. The purpose of this study was to assess the optimal gates number for each region and to improve quantitative estimation of tumor

  4. Improved attenuation correction for respiratory gated PET/CT with extended-duration cine CT: a simulation study

    Science.gov (United States)

    Zhang, Ruoqiao; Alessio, Adam M.; Pierce, Larry A.; Byrd, Darrin W.; Lee, Tzu-Cheng; De Man, Bruno; Kinahan, Paul E.

    2017-03-01

    Due to the wide variability of intra-patient respiratory motion patterns, traditional short-duration cine CT used in respiratory gated PET/CT may be insufficient to match the PET scan data, resulting in suboptimal attenuation correction that eventually compromises the PET quantitative accuracy. Thus, extending the duration of cine CT can be beneficial to address this data mismatch issue. In this work, we propose to use a long-duration cine CT for respiratory gated PET/CT, whose cine acquisition time is ten times longer than a traditional short-duration cine CT. We compare the proposed long-duration cine CT with the traditional short-duration cine CT through numerous phantom simulations with 11 respiratory traces measured during patient PET/CT scans. Experimental results show that, the long-duration cine CT reduces the motion mismatch between PET and CT by 41% and improves the overall reconstruction accuracy by 42% on average, as compared to the traditional short-duration cine CT. The long-duration cine CT also reduces artifacts in PET images caused by misalignment and mismatch between adjacent slices in phase-gated CT images. The improvement in motion matching between PET and CT by extending the cine duration depends on the patient, with potentially greater benefits for patients with irregular breathing patterns or larger diaphragm movements.

  5. Monte Carlo modeling of a clinical PET scanner by using the GATE dedicated computer code; Modelagem Monte Carlo de um PET Scanner clinico utilizando o codigo dedicado GATE

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Igor Fagner; Lima, Fernando Roberto de Andrade, E-mail: falima@cnen.gov.b [Universidade Federal de Pernambuco (DEN/UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear; Universidade de Pernambuco (UPE), Recife, PE (Brazil). Escola Politecnica; Vieira, Jose Wilson [Universidade Federal de Pernambuco (DEN/UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear; Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2011-10-26

    This paper demonstrates more possible detailed the GATE simulated architecture involved in the 4D modeling of a General Electric PET scanner, the Advance. So, it were used data present in the literature on the configuration of GE modelled PET. The obtained results which were the 3D components of PET creation, and the simulation of 4D phenomena as the source decay and the gantry whirl, exhibit the potential of tool in emission tomograph modelling

  6. Ultra-low Dose CT for Attenuation Correction of 82Rb Cardiac PET

    DEFF Research Database (Denmark)

    Sørensen, Maria Balshøj; Bouchelouche, Kirsten; Tolbod, Lars Poulsen

    Aim: Myocardial perfusion imaging (MPI) using cardiac PET with tracers like 82Rb and 15O-water is substantially lower in radiation dose than classic MIBI-based SPECT. However, for cardiac PET, the dose contribution of CT for attenuation correction (CTAC) is typically 20-30% of the total dose....... To reduce the total radiation dose of cardiac PET further, we set out to examine if the use of ultra-low dose CTAC (UL-CTAC) would affect the accuracy of the quantitative parameters related to MPI. Furthermore, we examined whether the low quality of the UL-CTAC would affect the technologist’s ability...... to perform manual adjustment for misalignment between PET and CTAC. The CT reconstruction algorithm Q.AC was used to improve quality and consistency of the CTAC. Method: 23 consecutive clinical patients (BMI: 26.9 [range: 15.4-38.8]) referred for 82Rb PET rest and stress imaging were included in the study...

  7. ECG-gating in non-cardiac digital subtraction angiography

    International Nuclear Information System (INIS)

    Gattoni, F.; Baldini, V.; Cairo, F.

    1987-01-01

    This paper reports the results of the ECG-gating in non-cardiac digital subtraction angiography (DSA). One hundred and fifteen patients underwent DSA (126 examinations); ECG-gating was applied in 66/126 examinations: images recorded at 70% of R wave were subtracted. Artifacts produced by vascular movements were evaluated in all patients: only 40 examinations, carried out whithout ECG-gating, showed vascular artifacts. The major advantage of the ECG-gated DSA is the more efficent subtraction because of the better images superimposition: therefore, ECG-gating can be clinically helpful. On the contrary, it could be a problem in arrhytmic or bradycardic patients. ECG-gating is helpful in DSA imaging of the thoracic and abdominal aorta and of the cervical and renal arteries. In the examinations of peripheral vessels of the limbs it is not so efficent as in the trunk or in the neck

  8. End-expiration respiratory gating for a high-resolution stationary cardiac SPECT system

    International Nuclear Information System (INIS)

    Chan, Chung; Sinusas, Albert J; Liu, Chi; Harris, Mark; Le, Max; Biondi, James; Grobshtein, Yariv; Liu, Yi-Hwa

    2014-01-01

    Respiratory and cardiac motions can degrade myocardial perfusion SPECT (MPS) image quality and reduce defect detection and quantitative accuracy. In this study, we developed a dual respiratory and cardiac gating system for a high-resolution fully stationary cardiac SPECT scanner in order to improve the image quality and defect detection. Respiratory motion was monitored using a compressive sensor pillow connected to a dual respiratory–cardiac gating box, which sends cardiac triggers only during end-expiration phases to the single cardiac trigger input on the SPECT scanners. The listmode data were rebinned retrospectively into end-expiration frames for respiratory motion reduction or eight cardiac gates only during end-expiration phases to compensate for both respiratory and cardiac motions. The proposed method was first validated on a motion phantom in the presence and absence of multiple perfusion defects, and then applied on 11 patient studies with and without perfusion defects. In the normal phantom studies, the end-expiration gated SPECT (EXG-SPECT) reduced respiratory motion blur and increased myocardium to blood pool contrast by 51.2% as compared to the ungated images. The proposed method also yielded an average of 11.2% increase in myocardium to defect contrast as compared to the ungated images in the phantom studies with perfusion defects. In the patient studies, EXG-SPECT significantly improved the myocardium to blood pool contrast (p < 0.005) by 24% on average as compared to the ungated images, and led to improved perfusion uniformity across segments on polar maps for normal patients. For a patient with defect, EXG-SPECT improved the defect contrast and definition. The dual respiratory–cardiac gating further reduced the blurring effect, increased the myocardium to blood pool contrast significantly by 36% (p < 0.05) compared to EXG-SPECT, and further improved defect characteristics and visualization of fine structures at the expense of increased

  9. Cardiac pathologies incidentally detected with non-gated chest CT; Inzidentelle Pathologien des Herzens im Thorax-CT

    Energy Technology Data Exchange (ETDEWEB)

    Scherer, Axel; Kroepil, P.; Lanzman, R.S.; Moedder, U. [Inst. fuer Radiologie, Universitaetsklinikum Duesseldorf, Heinrich-Heine-Univ. (Germany); Choy, G.; Abbara, S. [Cardiovascular Imaging Section, Massachusetts General Hospital, Harvard Medical School (United States)

    2009-12-15

    Cardiac imaging using electrocardiogram-gated multi-detector computed tomography (MDCT) permits noninvasive diagnosis of congenital and acquired cardiac pathologies and has thus become increasingly important in the last years. Several studies investigated the incidence and relevance of incidental extracardiac structures within the lungs, mediastinum, chest wall, and abdomen with gated coronary CT. This resulted in the general acceptance of the review of extracardiac structures as a routine component of coronary CT interpretation. On the other hand radiologists tend to neglect pericardial and cardiac pathologies in non-gated chest CT, which is primarily performed for the evaluation of the respiratory system or for tumor staging. Since the introduction of multi-detector spiral CT technology, the incidental detection of cardiac and pericardial findings has become possible using non-gated chest CT. This article reviews the imaging appearances and differential diagnostic considerations of incidental cardiac entities that may be encountered in non-gated chest CT. (orig.)

  10. Dynamic respiratory gated 18FDG-PET of lung tumors - a feasibility study

    International Nuclear Information System (INIS)

    Skjei Knudtsen, Ingerid; Skretting, Arne; Roedal, Jan; Brustugun, Odd Terje; Helland, Aaslaug; Malinen, Eirik

    2011-01-01

    Background. 18 FDG-PET/CT imaging is well established for diagnosis and staging of lung tumors. However, more detailed information regarding the distribution of FDG within the tumor, also as a function of time after injection may be relevant. In this study we explore the feasibility of a combined dynamic and respiratory gated (DR) PET protocol. Material and methods. A DR FDG-PET protocol for a Siemens Biograph 16 PET/CT scanner was set up, allowing data acquisition from the time of FDG injection. Breath-hold (BH) respiratory gating was performed at four intervals over a total acquisition time of 50 minutes. Thus, the PET protocol provides both motion-free images and a spatiotemporal characterization of the glucose distribution in lung tumors. Software tools were developed in-house for tentative tumor segmentation and for extracting standard uptake values (SUVs) voxel by voxel, tumor volumes and SUV gradients in all directions. Results. Four pilot patients have been investigated with the DR PET protocol. The procedure was well tolerated by the patients. The BH images appeared sharper, and SUV max /SUV mean was higher, compared to free breathing (FB) images. Also, SUV gradients in the periphery of the tumor in the BH images were in general greater than or equal to the gradients in the FB PET images. Conclusion. The DR FDG-PET protocol is feasible and the BH images have a superior quality compared to the FB images. The protocol may also provide information of relevance for radiotherapy planning and follow-up. A patient trial is needed for assessing the clinical value of the imaging protocol

  11. Bayesian Penalized Likelihood Image Reconstruction (Q.Clear) in 82Rb Cardiac PET: Impact of Count Statistics

    DEFF Research Database (Denmark)

    Christensen, Nana Louise; Tolbod, Lars Poulsen

    PET scans. 3) Static and dynamic images from a set of 7 patients (BSA: 1.6-2.2 m2) referred for 82Rb cardiac PET was analyzed using a range of beta factors. Results were compared to the institution’s standard clinical practice reconstruction protocol. All scans were performed on GE DMI Digital......Aim: Q.Clear reconstruction is expected to improve detection of perfusion defects in cardiac PET due to the high degree of image convergence and effective noise suppression. However, 82Rb (T½=76s) possess a special problem, since count statistics vary significantly not only between patients...... statistics using a cardiac PET phantom as well as a selection of clinical patients referred for 82Rb cardiac PET. Methods: The study consistent of 3 parts: 1) A thorax-cardiac phantom was scanned for 10 minutes after injection of 1110 MBq 82Rb. Frames at 3 different times after infusion were reconstructed...

  12. Cardiac 82rubidium PET/CT: initial European experience

    International Nuclear Information System (INIS)

    Groves, Ashley M.; Dickson, John C.; Kayani, Irfan; Endozo, Raymondo; Blanchard, Patty; Shastry, Manu; Prvulovich, Elizabeth; Waddington, Wendy A.; Ben-Haim, Simona; Bomanji, Jamshed B.; Ell, Peter J.; Speechly-Dick, Marie-Elsya; McEwan, Jean R.

    2007-01-01

    Myocardial perfusion with PET/CT has advantages over conventional SPECT. We describe our initial European experience using 82 Rubidium-PET/CT, as part of a clinical myocardial perfusion service. We studied the first 100 patients (64 male; 36 female, mean age = 60: SD +/-12.5y, mean body mass index = 30: SD +/-6.9kg/m 2 ) who underwent 82 Rubidium cardiac PET/CT in our institution. Thirty patients had recently undergone coronary angiography. Patients underwent imaging during adenosine infusion and at rest. Images were acquired over 5 minutes using a GE-PET/CT instrument. Image quality was described as good, adequate or inadequate. Images were reported patient-by-patient by a minimum of five nuclear medicine physicians. A segment-by-segment analysis (17-segment model) was also performed. Image quality was good in 77%, adequate 23% and inadequate 0%. There was no statistical difference in image quality between obese and non-obese patients (Fisher's exact test, p = 0.2864). 59% had normal perfusion studies, 29% had inducible ischaemia, 12% had myocardial infarction (11% with super added ischaemia). There was reduced 82 Rubidium uptake in 132/1700 segments during stress. There was reduced 82 Rubidium uptake at rest in 42/1700 segments. The 82 Rubidium PET/CT findings were consistent with the angiographic findings in 28/30 cases. We show that, even from initial use of 82 Rubidium, it is possible to perform myocardial perfusion studies quickly with good image quality, even in the obese. The PET findings correlated well in the third of the cases where angiography was available. As such, 82 Rubidium cardiac PET/CT is likely to be an exciting addition to the European nuclear physician/ cardiologist's radionuclide imaging arsenal. (orig.)

  13. Feasibility of epicardial adipose tissue quantification in non-ECG-gated low-radiation-dose CT: comparison with prospectively ECG-gated cardiac CT

    Energy Technology Data Exchange (ETDEWEB)

    Simon-Yarza, Isabel; Viteri-Ramirez, Guillermo; Saiz-Mendiguren, Ramon; Slon-Roblero, Pedro J.; Paramo, Maria [Dept. of Radiology, Clinica Univ. de Navarra, Pamplona (Spain); Bastarrika, Gorka [Dept. of Radiology, Clinica Univ. de Navarra, Pamplona (Spain); Cardiac Imaging Unit, Clinica Univ. de Navarra, Pamplona (Spain)], e-mail: bastarrika@unav.es

    2012-06-15

    Background: Epicardial adipose tissue (EAT) is an important indicator of cardiovascular risk. This parameter is generally assessed on ECG-gated computed tomography (CT) images. Purpose: To evaluate feasibility and reliability of EAT quantification on non-gated thoracic low-radiation-dose CT examinations with respect to prospectively ECG-gated cardiac CT acquisition. Material and Methods: Sixty consecutive asymptomatic smokers (47 men; mean age 64 {+-} 9.8 years) underwent low-dose CT of the chest and prospectively ECG-gated cardiac CT acquisitions (64-slice dual-source CT). The two examinations were reconstructed with the same range, field of view, slice thickness, and convolution algorithm. Two independent observers blindly quantified EAT volume using commercially available software. Data were compared with paired sample Student t-test, concordance correlation coefficients (CCC), and Bland-Altman plots. Results: No statistically significant difference was observed for EAT volume quantification with low-dose-CT (141.7 {+-} 58.3 mL) with respect to ECG-gated CT (142.7 {+-} 57.9 mL). Estimation of CCC showed almost perfect concordance between the two techniques for EAT-volume assessment (CCC, 0.99; mean difference, 0.98 {+-} 5.1 mL). Inter-observer agreement for EAT volume estimation was CCC: 0.96 for low-dose-CT examinations and 0.95 for ECG-gated CT. Conclusion: Non-gated low-dose CT allows quantifying EAT with almost the same concordance and reliability as using dedicated prospectively ECG-gated cardiac CT acquisition protocols.

  14. Feasibility of epicardial adipose tissue quantification in non-ECG-gated low-radiation-dose CT: comparison with prospectively ECG-gated cardiac CT

    International Nuclear Information System (INIS)

    Simon-Yarza, Isabel; Viteri-Ramirez, Guillermo; Saiz-Mendiguren, Ramon; Slon-Roblero, Pedro J.; Paramo, Maria; Bastarrika, Gorka

    2012-01-01

    Background: Epicardial adipose tissue (EAT) is an important indicator of cardiovascular risk. This parameter is generally assessed on ECG-gated computed tomography (CT) images. Purpose: To evaluate feasibility and reliability of EAT quantification on non-gated thoracic low-radiation-dose CT examinations with respect to prospectively ECG-gated cardiac CT acquisition. Material and Methods: Sixty consecutive asymptomatic smokers (47 men; mean age 64 ± 9.8 years) underwent low-dose CT of the chest and prospectively ECG-gated cardiac CT acquisitions (64-slice dual-source CT). The two examinations were reconstructed with the same range, field of view, slice thickness, and convolution algorithm. Two independent observers blindly quantified EAT volume using commercially available software. Data were compared with paired sample Student t-test, concordance correlation coefficients (CCC), and Bland-Altman plots. Results: No statistically significant difference was observed for EAT volume quantification with low-dose-CT (141.7 ± 58.3 mL) with respect to ECG-gated CT (142.7 ± 57.9 mL). Estimation of CCC showed almost perfect concordance between the two techniques for EAT-volume assessment (CCC, 0.99; mean difference, 0.98 ± 5.1 mL). Inter-observer agreement for EAT volume estimation was CCC: 0.96 for low-dose-CT examinations and 0.95 for ECG-gated CT. Conclusion: Non-gated low-dose CT allows quantifying EAT with almost the same concordance and reliability as using dedicated prospectively ECG-gated cardiac CT acquisition protocols

  15. Simulation Study of PET System Using GATE%基于GATE的PET系统仿真研究

    Institute of Scientific and Technical Information of China (English)

    刘豪佳; 张斌

    2014-01-01

    PET and SPECT is the most advanced nuclear medical imaging technology .GATE is a dedicated Monte Carlo simulation platform for PET and SPECT .This study validates two GATE models of Simens ECAT EXACT HR+PET scanner and Simens PET/CT Biograph 2.After the simulation of PET systems completed , testing and performance evaluation of simulation systems were proceeded according to NEMA 2001 performance protocols , including spatial resolution , scatter fraction and sensitivity .Test results show that , performances of GATE simulation systems agree well with the experimental values .%PET和SPECT是现代核医学最高水平的影像技术,GATE是专用于PET和SPECT的蒙特卡罗仿真工具。研究以西门子公司的PET扫描仪 ECAT EXACT HR+和PET/CT Biograph2为原型,分别使用GATE实现其系统的完整仿真。依据NEMA 2001标准,对仿真系统的空间分辨率、散射分数和灵敏度分别进行测试与评估。测试结果表明,仿真系统性能参数和实验结果之间具有良好的一致性。

  16. Simultaneous cardiac output and regional myocardial perfusion determination with PET and nitrogen 13 ammonia

    DEFF Research Database (Denmark)

    Hove, Jens D; Kofoed, Klaus F; Wu, Hsiao M

    2003-01-01

    The purpose of this study was to evaluate the possibility of measuring cardiac output during positron emission tomography (PET) examination of myocardial perfusion with nitrogen 13 ammonia.......The purpose of this study was to evaluate the possibility of measuring cardiac output during positron emission tomography (PET) examination of myocardial perfusion with nitrogen 13 ammonia....

  17. Heterogeneous response of cardiac sympathetic function to cardiac resynchronization therapy in heart failure documented by 11[C]-hydroxy-ephedrine and PET/CT

    International Nuclear Information System (INIS)

    Capitanio, Selene; Nanni, Cristina; Marini, Cecilia; Bonfiglioli, Rachele; Martignani, Cristian; Dib, Bassam; Fuccio, Chiara; Boriani, Giuseppe; Picori, Lorena; Boschi, Stefano; Morbelli, Silvia

    2015-01-01

    Introduction: Cardiac resynchronization therapy (CRT) is an accepted treatment in patients with end-stage heart failure. PET permits the absolute quantification of global and regional homogeneity in cardiac sympathetic innervation. We evaluated the variation of cardiac adrenergic activity in patients with idiopathic heart failure (IHF) disease (NYHA III–IV) after CRT using 11 C-hydroxyephedrine (HED) PET/CT. Methods: Ten IHF patients (mean age = 68; range = 55–81; average left ventricular ejection fraction 26 ± 4%) implanted with a resynchronization device underwent three HED PET/CT studies: PET 1 one week after inactive device implantation; PET 2, one week after PET 1 under stimulated rhythm; PET 3, at 3 months under active CRT. A dedicated software (PMOD 3.4 version) was used to estimate global and regional cardiac uptake of HED through 17 segment polar maps. Results: At baseline, HED uptake was heterogeneously distributed throughout the left ventricle with a variation coefficient of 18 ± 5%. This variable markedly decreased after three months CRT (12 ± 5%, p < 0.01). Interestingly, subdividing the 170 myocardial segments (17 segments of each patient multiplied by the number of patients) into two groups, according to the median value of tracer uptake expressed as % of maximal myocardial uptake (76%), we observed a different behaviour depending on baseline innervation: HED uptake significantly increased only in segments with “impaired innervation” (SUV 2.61 ± 0.92 at PET1 and 3.05 ± 1.67 at three months, p < 0.01). Conclusion: As shown by HED PET/CT uptake and distribution, improvement in homogeneity of myocardial neuronal function reflected a selective improvement of tracer uptake in regions with more severe neuronal damage. Advances in Knowledge: These finding supported the presence of a myocardial regional variability in response of cardiac sympathetic system to CRT and a systemic response involving remote tissues with rich adrenergic innervation

  18. Sources of attenuation-correction artefacts in cardiac PET/CT and SPECT/CT.

    Science.gov (United States)

    McQuaid, Sarah J; Hutton, Brian F

    2008-06-01

    Respiratory motion during myocardial perfusion imaging can cause artefacts in both positron emission tomography (PET) and single-photon emission computed tomography (SPECT) images when mismatches between emission and transmission datasets arise. In this study, artefacts from different breathing motions were quantified in both modalities to assess key factors in attenuation-correction accuracy. Activity maps were generated using the NURBS-based cardiac-torso phantom for different respiratory cycles, which were projected, attenuation-corrected and reconstructed to form PET and SPECT images. Attenuation-correction was performed with maps at mismatched respiratory phases to observe the effect on the left-ventricular myocardium. Myocardial non-uniformity was assessed in terms of the standard deviation in scores obtained from the 17-segment model and changes in uniformity were compared for each mismatch and modality. Certain types of mismatch led to artefacts and corresponding increases in the myocardial non-uniformity. For each mismatch in PET, the increases in non-uniformity relative to an artefact-free image were as follows: (a) cardiac translation mismatch, 84% +/- 11%; (b) liver mismatch, 59% +/- 10%, (c) lung mismatch from diaphragm contraction, 28% +/- 8%; and (d) lung mismatch from chest-wall motion, 6% +/- 7%. The corresponding factors for SPECT were (a) 61% +/- 8%, (b) 34% +/- 8%, (c) -2% +/- 7)% and (d) -4% +/- 6%. Attenuation-correction artefacts were seen in PET and SPECT images, with PET being more severely affected. The most severe artefacts were produced from mismatches in cardiac and liver position, whereas lung mismatches were less critical. Both cardiac and liver positions must, therefore, be correctly matched during attenuation correction.

  19. Evaluation of a direct motion estimation/correction method in respiratory-gated PET/MRI with motion-adjusted attenuation.

    Science.gov (United States)

    Bousse, Alexandre; Manber, Richard; Holman, Beverley F; Atkinson, David; Arridge, Simon; Ourselin, Sébastien; Hutton, Brian F; Thielemans, Kris

    2017-06-01

    Respiratory motion compensation in PET/CT and PET/MRI is essential as motion is a source of image degradation (motion blur, attenuation artifacts). In previous work, we developed a direct method for joint image reconstruction/motion estimation (JRM) for attenuation-corrected (AC) respiratory-gated PET, which uses a single attenuation-map (μ-map). This approach was successfully implemented for respiratory-gated PET/CT, but since it relied on an accurate μ-map for motion estimation, the question of its applicability in PET/MRI is open. The purpose of this work is to investigate the feasibility of JRM in PET/MRI and to assess the robustness of the motion estimation when a degraded μ-map is used. We performed a series of JRM reconstructions from simulated PET data using a range of simulated Dixon MRI sequence derived μ-maps with wrong attenuation values in the lungs, from -100% (no attenuation) to +100% (double attenuation), as well as truncated arms. We compared the estimated motions with the one obtained from JRM in ideal conditions (no noise, true μ-map as an input). We also applied JRM on 4 patient datasets of the chest, 3 of them containing hot lesions. Patient list-mode data were gated using a principal component analysis method. We compared SUV max values of the JRM reconstructed activity images and non motion-corrected images. We also assessed the estimated motion fields by comparing the deformed JRM-reconstructed activity with individually non-AC reconstructed gates. Experiments on simulated data showed that JRM-motion estimation is robust to μ-map degradation in the sense that it produces motion fields similar to the ones obtained when using the true μ-map, regardless of the attenuation errors in the lungs (PET/MRI clinical datasets. It provides a potential alternative to existing methods where the motion fields are pre-estimated from separate MRI measurements. © 2017 University College London (UCL). Medical Physics published by Wiley Periodicals, Inc

  20. A priori motion models for four-dimensional reconstruction in gated cardiac SPECT

    International Nuclear Information System (INIS)

    Lalush, D.S.; Tsui, B.M.W.; Cui, Lin

    1996-01-01

    We investigate the benefit of incorporating a priori assumptions about cardiac motion in a fully four-dimensional (4D) reconstruction algorithm for gated cardiac SPECT. Previous work has shown that non-motion-specific 4D Gibbs priors enforcing smoothing in time and space can control noise while preserving resolution. In this paper, we evaluate methods for incorporating known heart motion in the Gibbs prior model. The new model is derived by assigning motion vectors to each 4D voxel, defining the movement of that volume of activity into the neighboring time frames. Weights for the Gibbs cliques are computed based on these open-quotes most likelyclose quotes motion vectors. To evaluate, we employ the mathematical cardiac-torso (MCAT) phantom with a new dynamic heart model that simulates the beating and twisting motion of the heart. Sixteen realistically-simulated gated datasets were generated, with noise simulated to emulate a real Tl-201 gated SPECT study. Reconstructions were performed using several different reconstruction algorithms, all modeling nonuniform attenuation and three-dimensional detector response. These include ML-EM with 4D filtering, 4D MAP-EM without prior motion assumption, and 4D MAP-EM with prior motion assumptions. The prior motion assumptions included both the correct motion model and incorrect models. Results show that reconstructions using the 4D prior model can smooth noise and preserve time-domain resolution more effectively than 4D linear filters. We conclude that modeling of motion in 4D reconstruction algorithms can be a powerful tool for smoothing noise and preserving temporal resolution in gated cardiac studies

  1. MR-based attenuation correction for cardiac FDG PET on a hybrid PET/MRI scanner: comparison with standard CT attenuation correction

    Energy Technology Data Exchange (ETDEWEB)

    Vontobel, Jan; Liga, Riccardo; Possner, Mathias; Clerc, Olivier F.; Mikulicic, Fran; Veit-Haibach, Patrick; Voert, Edwin E.G.W. ter; Fuchs, Tobias A.; Stehli, Julia; Pazhenkottil, Aju P.; Benz, Dominik C.; Graeni, Christoph; Gaemperli, Oliver; Herzog, Bernhard; Buechel, Ronny R.; Kaufmann, Philipp A. [University Hospital Zurich, Department of Nuclear Medicine, Zurich (Switzerland)

    2015-09-15

    The aim of this study was to evaluate the feasibility of attenuation correction (AC) for cardiac {sup 18}F-labelled fluorodeoxyglucose (FDG) positron emission tomography (PET) using MR-based attenuation maps. We included 23 patients with no known cardiac history undergoing whole-body FDG PET/CT imaging for oncological indications on a PET/CT scanner using time-of-flight (TOF) and subsequent whole-body PET/MR imaging on an investigational hybrid PET/MRI scanner. Data sets from PET/MRI (with and without TOF) were reconstructed using MR AC and semi-quantitative segmental (20-segment model) myocardial tracer uptake (per cent of maximum) and compared to PET/CT which was reconstructed using CT AC and served as standard of reference. Excellent correlations were found for regional uptake values between PET/CT and PET/MRI with TOF (n = 460 segments in 23 patients; r = 0.913; p < 0.0001) with narrow Bland-Altman limits of agreement (-8.5 to +12.6 %). Correlation coefficients were slightly lower between PET/CT and PET/MRI without TOF (n = 460 segments in 23 patients; r = 0.851; p < 0.0001) with broader Bland-Altman limits of agreement (-12.5 to +15.0 %). PET/MRI with and without TOF showed minimal underestimation of tracer uptake (-2.08 and -1.29 %, respectively), compared to PET/CT. Relative myocardial FDG uptake obtained from MR-based attenuation corrected FDG PET is highly comparable to standard CT-based attenuation corrected FDG PET, suggesting interchangeability of both AC techniques. (orig.)

  2. Highly-accelerated self-gated free-breathing 3D cardiac cine MRI: validation in assessment of left ventricular function.

    Science.gov (United States)

    Liu, Jing; Feng, Li; Shen, Hsin-Wei; Zhu, Chengcheng; Wang, Yan; Mukai, Kanae; Brooks, Gabriel C; Ordovas, Karen; Saloner, David

    2017-08-01

    This work presents a highly-accelerated, self-gated, free-breathing 3D cardiac cine MRI method for cardiac function assessment. A golden-ratio profile based variable-density, pseudo-random, Cartesian undersampling scheme was implemented for continuous 3D data acquisition. Respiratory self-gating was achieved by deriving motion signal from the acquired MRI data. A multi-coil compressed sensing technique was employed to reconstruct 4D images (3D+time). 3D cardiac cine imaging with self-gating was compared to bellows gating and the clinical standard breath-held 2D cine imaging for evaluation of self-gating accuracy, image quality, and cardiac function in eight volunteers. Reproducibility of 3D imaging was assessed. Self-gated 3D imaging provided an image quality score of 3.4 ± 0.7 vs 4.0 ± 0 with the 2D method (p = 0.06). It determined left ventricular end-systolic volume as 42.4 ± 11.5 mL, end-diastolic volume as 111.1 ± 24.7 mL, and ejection fraction as 62.0 ± 3.1%, which were comparable to the 2D method, with bias ± 1.96 × SD of -0.8 ± 7.5 mL (p = 0.90), 2.6 ± 3.3 mL (p = 0.84) and 1.4 ± 6.4% (p = 0.45), respectively. The proposed 3D cardiac cine imaging method enables reliable respiratory self-gating performance with good reproducibility, and provides comparable image quality and functional measurements to 2D imaging, suggesting that self-gated, free-breathing 3D cardiac cine MRI framework is promising for improved patient comfort and cardiac MRI scan efficiency.

  3. Physics process level discrimination of detections for GATE: assessment of contamination in SPECT and spurious activity in PET.

    Science.gov (United States)

    De Beenhouwer, Jan; Staelens, Steven; Vandenberghe, Stefaan; Verhaeghe, Jeroen; Van Holen, Roel; Rault, Erwann; Lemahieu, Ignace

    2009-04-01

    The GEANT4 application for tomographic emission (GATE) is one of the most detailed Monte Carlo simulation tools for SPECT and PET. It allows for realistic phantoms, complex decay schemes, and a large variety of detector geometries. However, only a fraction of the information in each particle history is available for postprocessing. In order to extend the analysis capabilities of GATE, a flexible framework was developed. This framework allows all detected events to be subdivided according to their type: In PET, true coincidences from others, and in SPECT, geometrically collimated photons from others. The framework of the authors can be applied to any isotope, phantom, and detector geometry available in GATE. It is designed to enhance the usability of GATE for the study of contamination and for the investigation of the properties of current and future prototype detectors. The authors apply the framework to a case study of Bexxar, first assuming labeling with 124I, then with 131I. It is shown that with 124I PET, results with an optimized window improve upon those with the standard window but achieve less than half of the ideal improvement. Nevertheless, 124I PET shows improved resolution compared to 131I SPECT with triple-energy-window scatter correction.

  4. First experience of combined cardiac PET/64-detector CT angiography with invasive angiographic validation

    International Nuclear Information System (INIS)

    Groves, Ashley M.; Kayani, Irfan; Endozo, Raymondo; Menezes, Leon J.; Prvulovich, Elizabeth; Ell, Peter J.; Speechly-Dick, Marie-Elsya; McEwan, Jean; Pugliese, Francesca; Habib, Said B.

    2009-01-01

    Despite modern CT systems and expert evaluators, the diagnostic performance of coronary CT angiography is limited by overestimation of vessel stenosis which reduces the positive predictive value (PPV) of the test. The aim of this study was to evaluate the performance of combined cardiac PET/64-detector CT angiography. Included in this retrospective study were 33 consecutive patients (5 women, 28 men; mean age 61.6 years, range 47-87 years, mean BMI 27.3±5.2 kg/m 2 ) with clinically suspected flow-limiting coronary artery disease who underwent combined cardiac PET/64-detector CT angiography and invasive angiography. Combined PET/CT images were reported by an experienced dual-accredited radiologist/nuclear physician. An experienced cardiac CT radiologist re-read the CT images without PET. Stenotic disease was defined as >50% vessel narrowing. Invasive coronary angiography was used as a reference standard. Local ethics committee approval and patient consent were obtained. CT angiography (without PET data) was concordant with invasive angiography in 31/33 patients and at a patient level, the sensitivity in detecting significant coronary artery lesions was 100%, the specificity was 82%, the PPV was 92% and the negative predictive value (NPV) was 100%. Using combined PET/CT angiography the findings were concordant with invasive angiography in 32/33 patients and at a patient level, the sensitivity was 96%, the specificity was 100%, the PPV was 100% and the NPV was 91%. The use of integrated cardiac PET/64-detector CT angiography is feasible and appears to improve some aspects of the diagnostic performance of 64-detector coronary artery angiography in detecting coronary artery disease. (orig.)

  5. The diagnostic relevance of an integrated approach to gated cardiac studies

    International Nuclear Information System (INIS)

    Pavel, D.G.

    1982-01-01

    Evolution of Nuclear Medicine hardware and software has opened the way towards maximizing the amount of information of gated cardiac studies. The clinical use of cardiac functional images started with stroke volume image, paradoxis images and regional ejection fraction images, followed later by slope images, variation images and others. Especially the introduction of phase analysis has opened a variety of new perspectives. (WU)

  6. Automatic Extraction of Myocardial Mass and Volume Using Parametric Images from Dynamic Nongated PET.

    Science.gov (United States)

    Harms, Hendrik Johannes; Stubkjær Hansson, Nils Henrik; Tolbod, Lars Poulsen; Kim, Won Yong; Jakobsen, Steen; Bouchelouche, Kirsten; Wiggers, Henrik; Frøkiaer, Jørgen; Sörensen, Jens

    2016-09-01

    Dynamic cardiac PET is used to quantify molecular processes in vivo. However, measurements of left ventricular (LV) mass and volume require electrocardiogram-gated PET data. The aim of this study was to explore the feasibility of measuring LV geometry using nongated dynamic cardiac PET. Thirty-five patients with aortic-valve stenosis and 10 healthy controls underwent a 27-min (11)C-acetate PET/CT scan and cardiac MRI (CMR). The controls were scanned twice to assess repeatability. Parametric images of uptake rate K1 and the blood pool were generated from nongated dynamic data. Using software-based structure recognition, the LV wall was automatically segmented from K1 images to derive functional assessments of LV mass (mLV) and wall thickness. End-systolic and end-diastolic volumes were calculated using blood pool images and applied to obtain stroke volume and LV ejection fraction (LVEF). PET measurements were compared with CMR. High, linear correlations were found for LV mass (r = 0.95), end-systolic volume (r = 0.93), and end-diastolic volume (r = 0.90), and slightly lower correlations were found for stroke volume (r = 0.74), LVEF (r = 0.81), and thickness (r = 0.78). Bland-Altman analyses showed significant differences for mLV and thickness only and an overestimation for LVEF at lower values. Intra- and interobserver correlations were greater than 0.95 for all PET measurements. PET repeatability accuracy in the controls was comparable to CMR. LV mass and volume are accurately and automatically generated from dynamic (11)C-acetate PET without electrocardiogram gating. This method can be incorporated in a standard routine without any additional workload and can, in theory, be extended to other PET tracers. © 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

  7. Monte Carlo modeling of a clinical PET scanner by using the GATE dedicated computer code

    International Nuclear Information System (INIS)

    Vieira, Igor Fagner; Lima, Fernando Roberto de Andrade

    2011-01-01

    This paper demonstrates more possible detailed the GATE simulated architecture involved in the 4D modeling of a General Electric PET scanner, the Advance. So, it were used data present in the literature on the configuration of GE modelled PET. The obtained results which were the 3D components of PET creation, and the simulation of 4D phenomena as the source decay and the gantry whirl, exhibit the potential of tool in emission tomograph modelling

  8. Acquisition, processing and display of gated cardiac scintigrams

    International Nuclear Information System (INIS)

    Alpert, N.M.; Chesler, D.A.; McKusick, K.A.; Potsaid, M.S.; Pohost, G.M.; Dinsmore, R.A.

    1974-01-01

    An improved method for non-traumatic and essentially noninvasive evaluation of left ventricular (LV) function with /sup 99m/Tc as the tracer was developed. This method combines previously used EKG gating techniques for cardiac blood pool visualization with new computerized acquisition, processing and display techniques. An Anger camera, a small computer, and a physiological synchronizer are used to acquire a sequence of eight scintigrams which span the entire cardiac cycle. Under our present protocol two twenty-minute sequences are obtained, one an LAO (50 0 ) projection, the other an RAO (30 0 ) projection. Subsequently these images are processed on-line with a digital filter to increase definition of the cardiac borders. The eight images are then displayed sequentially on a specially designed electronic monitor to give an impression of the beating heart somewhat analogous to that obtained with invasive contrast angiography

  9. Detection of respiratory tumour motion using intrinsic list mode-driven gating in positron emission tomography.

    Science.gov (United States)

    Büther, Florian; Ernst, Iris; Dawood, Mohammad; Kraxner, Peter; Schäfers, Michael; Schober, Otmar; Schäfers, Klaus P

    2010-12-01

    Respiratory motion of organs during PET scans is known to degrade PET image quality, potentially resulting in blurred images, attenuation artefacts and erroneous tracer quantification. List mode-based gating has been shown to reduce these pitfalls in cardiac PET. This study evaluates these intrinsic gating methods for tumour PET scans. A total of 34 patients with liver or lung tumours (14 liver tumours and 27 lung tumours in all) underwent a 15-min single-bed list mode PET scan of the tumour region. Of these, 15 patients (8 liver and 11 lung tumours in total) were monitored by a video camera registering a marker on the patient's abdomen, thus capturing the respiratory motion for PET gating (video method). Further gating information was deduced by dividing the list mode stream into 200-ms frames, determining the number of coincidences (sensitivity method) and computing the axial centre of mass of the measured count rates in the same frames (centre of mass method). Additionally, these list mode-based methods were evaluated using only coincidences originating from the tumour region by segmenting the tumour in sinogram space (segmented sensitivity/centre of mass method). Measured displacement of the tumours between end-expiration and end-inspiration and the increase in apparent uptake in the gated images served as a measure for the exactness of gating. To estimate the accuracy, a thorax phantom study with moved activity sources simulating small tumours was also performed. All methods resolved the respiratory motion with varying success. The best results were seen in the segmented centre of mass method, on average leading to larger displacements and uptake values than the other methods. The simple centre of mass method performed worse in terms of displacements due to activities moving into the field of view during the respiratory cycle. Both sensitivity- and video-based methods lead to similar results. List mode-driven PET gating, especially the segmented centre of mass

  10. Gated magnetic resonance imaging of congenital cardiac malformations

    International Nuclear Information System (INIS)

    Fletcher, B.D.; Jocobstein, M.D.; Nelson, A.D.; Riemenschneider, T.A.; Alfidi, R.J.

    1984-01-01

    Magnetic resonance (MR) images of a variety of cardiac malformations in 19 patients aged 1 week to 33 years were obtained using pulse plethysmographic- or ECG-gated spin echo pulse sequences. Coronal, axial, and sagittal images displaying intracardiac structures with excellent spatial and contrast resolution were acquired during systole or diastole. It is concluded that MR will be a valuable noninvasive method of diagnosing congenital heart disease

  11. Self-gating MR imaging of the fetal heart: comparison with real cardiac triggering

    International Nuclear Information System (INIS)

    Yamamura, Jin; Frisch, Michael; Ecker, Hannes; Adam, Gerhard; Wedegaertner, Ulrike; Graessner, Joachim; Hecher, Kurt

    2011-01-01

    To investigate the self-gating technique for MR imaging of the fetal heart in a sheep model. MR images of 6 fetal sheep heart were obtained at 1.5T. For self-gating MRI of the fetal heart a cine SSFP in short axis, two and four chamber view was used. Self-gated images were compared with real cardiac triggered MR images (pulse-wave triggering). MRI of the fetal heart was performed using both techniques simultaneously. Image quality was assessed and the left ventricular volume and function were measured and compared. Compared with pulse-wave triggering, the self-gating technique produced slightly inferior images with artifacts. Especially the atrial septum could not be so clearly depicted. The contraction of the fetal heart was shown in cine sequences in both techniques. The average blood volumes could be measured with both techniques with no significant difference: at end-systole 3.1 ml (SD± 0.2), at end-diastole 4.9 ml (±0.2), with ejection fractions at 38.6%, respectively 39%. Both self-gating and pulse-wave triggered cardiac MRI of the fetal heart allowed the evaluation of anatomical structures and functional information. Images obtained by self-gating technique were slightly inferior than the pulse-wave triggered MRI. (orig.)

  12. Clinical evaluation of left ventricular wall thickness by combined technique with gated planer 201Tl image and gated cardiac pool image

    International Nuclear Information System (INIS)

    Nakai, Kenji; Katsuragawa, Shigehiko; Takahashi, Tsuneo; Matsushita, Kazuo; Kawamura, Akiyoshi

    1983-01-01

    To evaluate the left ventricular (LV) wall thickness, combined technique with gated planer 201-Thallium image and gated cardiac pool image was applied to 6 patients with hypertrophic cardiomyopathy (HCM) and 4 patients with secondary hypertrophy due to hypertension (HHD) proven by electrocardiography and ultrasonic-echocardiography. Scintigraphic pattern of hypertrophy on reconstructed planer 201 Tl image showed diffuse or asymmetrical apical hypertrophy in HHD, asymmetrical septal hypertrophy in HCM. It was very interesting that abnormal perfusion was shown in 201 Tl image, despite symmetrical hypertrophy in echocardiography. This techniques provided useful information for evaluating the LV wall thickness and cardiac performance. (author)

  13. Respiratory gated PET/CT of the liver: A novel method and its impact on the detection of colorectal liver metastases

    International Nuclear Information System (INIS)

    Schulz, Anselm; Godt, Johannes Clemens; Dormagen, Johann Baptist; Holtedahl, Jon Erik; Bogsrud, Trond Velde; Labori, Knut Jørgen; Kløw, Nils-Einar; Bach-Gansmo, Tore

    2015-01-01

    Highlights: • Combined PET/CT and respiratory gated PET/CT improved sensitivity significantly. • Respiratory gated PET/CT had greatest impact on detection of small CRLM <10 mm. • Our results were comparable to earlier reported more complex and expensive methods. • The method used is inexpensive and requires only limited additional imaging time. - Abstract: Purpose: To evaluate the diagnostic performance of a new method for respiratory gated positron emission tomography (rgPET/CT) for colorectal liver metastases (CRLM), secondly, to assess its additional value to standard PET/CT (PET/CT). Materials and methods: Forty-three patients scheduled for resection of suspected CRLM were prospectively included from September 2011 to January 2013. None of the patients had previously undergone treatment for their CRLM. All patients underwent PET/CT and rgPET/CT in the same session. For rgPET/CT an in-house developed electronic circuit was used which displayed a color-coded countdown for the patient. The patients held their breath according to the countdown and only the data from the inspiration breath-hold period was used for image reconstruction. Two independent and blinded readers evaluated both PET/CT and rgPET/CT separately. The reference standard was histopathological confirmation for 73 out of 131 CRLM and follow-up otherwise. Results: Reference standard identified 131 CRLM in 39/43 patients. Nine patients accounted for 25 mucinous CRLM. The overall per-lesion sensitivity for detection of CRLM was for PET/CT 60.0%, for rgPET/CT 63.1%, and for standard + rgPET/CT 67.7%, respectively. Standard + rgPET/CT was overall significantly more sensitive for CRLM compared to PET/CT (p = 0.002) and rgPET/CT (p = 0.031). The overall positive predictive value (PPV) for detection of CRLM was for PET/CT 97.5%, for rgPET/CT 95.3%, and for standard + rgPET/CT 93.6%, respectively. Conclusion: Combination of PET/CT and rgPET/CT improved the sensitivity significantly for CRLM. However

  14. Respiratory gated PET/CT of the liver: A novel method and its impact on the detection of colorectal liver metastases

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, Anselm, E-mail: anselm.schulz@gmail.com [Department of Radiology and Nuclear Medicine, Oslo University Hospital, Postboks Pb 4956 Nydalen, 0424 Oslo (Norway); Institute of Clinical Medicine, University of Oslo, P.O. Box 1171 Blindern, 0318 Oslo (Norway); Godt, Johannes Clemens, E-mail: UXGODJ@ous-hf.no [Department of Radiology and Nuclear Medicine, Oslo University Hospital, Postboks Pb 4956 Nydalen, 0424 Oslo (Norway); Institute of Clinical Medicine, University of Oslo, P.O. Box 1171 Blindern, 0318 Oslo (Norway); Dormagen, Johann Baptist, E-mail: UXJORM@ous-hf.no [Department of Radiology and Nuclear Medicine, Oslo University Hospital, Postboks Pb 4956 Nydalen, 0424 Oslo (Norway); Holtedahl, Jon Erik, E-mail: JONHOL@ous-hf.no [The Intervention Centre, Oslo University Hospital, Postboks 4950 Nydalen, 0424 Oslo (Norway); Bogsrud, Trond Velde, E-mail: tvbog@aol.com [Department of Radiology and Nuclear Medicine, Oslo University Hospital, Postboks Pb 4956 Nydalen, 0424 Oslo (Norway); Department of Nuclear Medicine and PET-Center, Aarhus University Hospital, Norrebrogade 44, DK-8000 Aarhus C (Denmark); Labori, Knut Jørgen, E-mail: uxknab@ous-hf.no [Department of Hepato-Pancreato-Biliary Surgery, Oslo University Hospital, Postboks 4950 Nydalen, 0424 Oslo (Norway); Kløw, Nils-Einar, E-mail: NILKLO@ous-hf.no [Department of Radiology and Nuclear Medicine, Oslo University Hospital, Postboks Pb 4956 Nydalen, 0424 Oslo (Norway); Institute of Clinical Medicine, University of Oslo, P.O. Box 1171 Blindern, 0318 Oslo (Norway); Bach-Gansmo, Tore, E-mail: bat@ous-hf.no [Department of Radiology and Nuclear Medicine, Oslo University Hospital, Postboks Pb 4956 Nydalen, 0424 Oslo (Norway)

    2015-08-15

    Highlights: • Combined PET/CT and respiratory gated PET/CT improved sensitivity significantly. • Respiratory gated PET/CT had greatest impact on detection of small CRLM <10 mm. • Our results were comparable to earlier reported more complex and expensive methods. • The method used is inexpensive and requires only limited additional imaging time. - Abstract: Purpose: To evaluate the diagnostic performance of a new method for respiratory gated positron emission tomography (rgPET/CT) for colorectal liver metastases (CRLM), secondly, to assess its additional value to standard PET/CT (PET/CT). Materials and methods: Forty-three patients scheduled for resection of suspected CRLM were prospectively included from September 2011 to January 2013. None of the patients had previously undergone treatment for their CRLM. All patients underwent PET/CT and rgPET/CT in the same session. For rgPET/CT an in-house developed electronic circuit was used which displayed a color-coded countdown for the patient. The patients held their breath according to the countdown and only the data from the inspiration breath-hold period was used for image reconstruction. Two independent and blinded readers evaluated both PET/CT and rgPET/CT separately. The reference standard was histopathological confirmation for 73 out of 131 CRLM and follow-up otherwise. Results: Reference standard identified 131 CRLM in 39/43 patients. Nine patients accounted for 25 mucinous CRLM. The overall per-lesion sensitivity for detection of CRLM was for PET/CT 60.0%, for rgPET/CT 63.1%, and for standard + rgPET/CT 67.7%, respectively. Standard + rgPET/CT was overall significantly more sensitive for CRLM compared to PET/CT (p = 0.002) and rgPET/CT (p = 0.031). The overall positive predictive value (PPV) for detection of CRLM was for PET/CT 97.5%, for rgPET/CT 95.3%, and for standard + rgPET/CT 93.6%, respectively. Conclusion: Combination of PET/CT and rgPET/CT improved the sensitivity significantly for CRLM. However

  15. The evaluation of cardiac tamponade risk in patients with pericardial effusion detected by non-gated chest CT.

    Science.gov (United States)

    Ohta, Yasutoshi; Miyoshi, Fuminori; Kaminou, Toshio; Kaetsu, Yasuhiro; Ogawa, Toshihide

    2016-05-01

    Although pericardial effusion is often identified using non-gated chest computed tomography (CT), findings predictive of cardiac tamponade have not been adequately established. To determine the findings predictive of clinical cardiac tamponade in patients with moderate to large pericardial effusion using non-gated chest CT. We performed a retrospective analysis of 134 patients with moderate to large pericardial effusion who were identified from among 4581 patients who underwent non-gated chest CT. Cardiac structural changes, including right ventricular outflow tract (RVOT), were qualitatively evaluated. The inferior vena cava ratio with hepatic (IVCupp) and renal portions (IVClow) and effusion size were measured. The diagnostic performance of each structural change was calculated, and multivariate analysis was used to determine the predictors of cardiac tamponade. Of the 134 patients (mean age, 70.3 years; 64 men), 37 (28%) had cardiac tamponade. The sensitivity and specificity were 76% and 74% for RVOT compression; 87% and 84% for an IVClow ratio ≥0.77; and 60% and 77% for an effusion size ≥25.5 mm, respectively. Multivariate logistic regression analysis demonstrated that RVOT compression, an IVClow ratio ≥0.77, and an effusion size ≥25.5 mm were independent predictors of cardiac tamponade. The combination of these three CT findings had a sensitivity, specificity, and accuracy of 81%, 95%, and 91%, respectively. In patients with moderate to large pericardial effusion, non-gated chest CT provides additional information for predicting cardiac tamponade. © The Foundation Acta Radiologica 2015.

  16. An evaluation of the ECG gated cardiac CT on old myocardial infarction

    International Nuclear Information System (INIS)

    Tanegashima, Kazuhiro; Tejima, Yasuaki; Nakasone, Noriyo; Hyodo, Haruo

    1984-01-01

    In order to examine the accuracy of ECG gated cardiac CT (G-CCT), G-CCT findings were compared with ECG and cardiac echographic findings in 25 cases of old myocardial infarction. From the detection rate according to the infarct area, abnormal findings in the anterior wall and the septum obtained from G-CCT were in good accordance with those from ECG. Although all of the G-CCT findings did not agree with those of cardiac echography in cases in which abnormal findings were seen in multiple areas, the detection rate of cardiac abnormal findings as a whole by G-CCT was the same as that by cardiac echography. (Namekawa K.)

  17. MRI-Based Nonrigid Motion Correction in Simultaneous PET/MRI

    Science.gov (United States)

    Chun, Se Young; Reese, Timothy G.; Ouyang, Jinsong; Guerin, Bastien; Catana, Ciprian; Zhu, Xuping; Alpert, Nathaniel M.; El Fakhri, Georges

    2014-01-01

    Respiratory and cardiac motion is the most serious limitation to whole-body PET, resulting in spatial resolution close to 1 cm. Furthermore, motion-induced inconsistencies in the attenuation measurements often lead to significant artifacts in the reconstructed images. Gating can remove motion artifacts at the cost of increased noise. This paper presents an approach to respiratory motion correction using simultaneous PET/MRI to demonstrate initial results in phantoms, rabbits, and nonhuman primates and discusses the prospects for clinical application. Methods Studies with a deformable phantom, a free-breathing primate, and rabbits implanted with radioactive beads were performed with simultaneous PET/MRI. Motion fields were estimated from concurrently acquired tagged MR images using 2 B-spline nonrigid image registration methods and incorporated into a PET list-mode ordered-subsets expectation maximization algorithm. Using the measured motion fields to transform both the emission data and the attenuation data, we could use all the coincidence data to reconstruct any phase of the respiratory cycle. We compared the resulting SNR and the channelized Hotelling observer (CHO) detection signal-to-noise ratio (SNR) in the motion-corrected reconstruction with the results obtained from standard gating and uncorrected studies. Results Motion correction virtually eliminated motion blur without reducing SNR, yielding images with SNR comparable to those obtained by gating with 5–8 times longer acquisitions in all studies. The CHO study in dynamic phantoms demonstrated a significant improvement (166%–276%) in lesion detection SNR with MRI-based motion correction as compared with gating (P < 0.001). This improvement was 43%–92% for large motion compared with lesion detection without motion correction (P < 0.001). CHO SNR in the rabbit studies confirmed these results. Conclusion Tagged MRI motion correction in simultaneous PET/MRI significantly improves lesion detection

  18. Influence of Respiratory Gating, Image Filtering, and Animal Positioning on High-Resolution Electrocardiography-Gated Murine Cardiac Single-Photon Emission Computed Tomography

    Directory of Open Access Journals (Sweden)

    Chao Wu

    2015-01-01

    Full Text Available Cardiac parameters obtained from single-photon emission computed tomographic (SPECT images can be affected by respiratory motion, image filtering, and animal positioning. We investigated the influence of these factors on ultra-high-resolution murine myocardial perfusion SPECT. Five mice were injected with 99m technetium (99mTc-tetrofosmin, and each was scanned in supine and prone positions in a U-SPECT-II scanner with respiratory and electrocardiographic (ECG gating. ECG-gated SPECT images were created without applying respiratory motion correction or with two different respiratory motion correction strategies. The images were filtered with a range of three-dimensional gaussian kernels, after which end-diastolic volumes (EDVs, end-systolic volumes (ESVs, and left ventricular ejection fractions were calculated. No significant differences in the measured cardiac parameters were detected when any strategy to reduce or correct for respiratory motion was applied, whereas big differences (> 5% in EDV and ESV were found with regard to different positioning of animals. A linear relationship (p < .001 was found between the EDV or ESV and the kernel size of the gaussian filter. In short, respiratory gating did not significantly affect the cardiac parameters of mice obtained with ultra-high-resolution SPECT, whereas the position of the animals and the image filters should be the same in a comparative study with multiple scans to avoid systematic differences in measured cardiac parameters.

  19. Accuracy and effectiveness of self-gating signals in free-breathing three-dimensional cardiac cine magnetic resonance imaging

    International Nuclear Information System (INIS)

    Li Shuo; Gao Song; Wang Lei; Zhu Yan-Chun; Yang Jie; Xie Yao-Qin; Fu Nan; Wang Yi

    2016-01-01

    Conventional multiple breath-hold two-dimensional (2D) balanced steady-state free precession (SSFP) presents many difficulties in cardiac cine magnetic resonance imaging (MRI). Recently, a self-gated free-breathing three-dimensional (3D) SSFP technique has been proposed as an alternative in many studies. However, the accuracy and effectiveness of self-gating signals have been barely studied before. Since self-gating signals are crucially important in image reconstruction, a systematic study of self-gating signals and comparison with external monitored signals are needed.Previously developed self-gated free-breathing 3D SSFP techniques are used on twenty-eight healthy volunteers. Both electrocardiographic (ECG) and respiratory bellow signals are also acquired during the scan as external signals. Self-gating signal and external signal are compared by trigger and gating window. Gating window is proposed to evaluate the accuracy and effectiveness of respiratory self-gating signal. Relative deviation of the trigger and root-mean-square-deviation of the cycle duration are calculated. A two-tailed paired t-test is used to identify the difference between self-gating and external signals. A Wilcoxon signed rank test is used to identify the difference between peak and valley self-gating triggers.The results demonstrate an excellent correlation ( P = 0, R > 0.99) between self-gating and external triggers. Wilcoxon signed rank test shows that there is no significant difference between peak and valley self-gating triggers for both cardiac ( H = 0, P > 0.10) and respiratory ( H = 0, P > 0.44) motions. The difference between self-gating and externally monitored signals is not significant (two-tailed paired-sample t-test: H = 0, P > 0.90).The self-gating signals could demonstrate cardiac and respiratory motion accurately and effectively as ECG and respiratory bellow. The difference between the two methods is not significant and can be explained. Furthermore, few ECG trigger errors

  20. Seismocardiography-Based Cardiac Computed Tomography Gating Using Patient-Specific Template Identification and Detection.

    Science.gov (United States)

    Yao, Jingting; Tridandapani, Srini; Wick, Carson A; Bhatti, Pamela T

    2017-01-01

    To more accurately trigger cardiac computed tomography angiography (CTA) than electrocardiography (ECG) alone, a sub-system is proposed as an intermediate step toward fusing ECG with seismocardiography (SCG). Accurate prediction of quiescent phases is crucial to prospectively gating CTA, which is susceptible to cardiac motion and, thus, can affect the diagnostic quality of images. The key innovation of this sub-system is that it identifies the SCG waveform corresponding to heart sounds and determines their phases within the cardiac cycles. Furthermore, this relationship is modeled as a linear function with respect to heart rate. For this paper, B-mode echocardiography is used as the gold standard for identifying the quiescent phases. We analyzed synchronous ECG, SCG, and echocardiography data acquired from seven healthy subjects (mean age: 31; age range: 22-48; males: 4) and 11 cardiac patients (mean age: 56; age range: 31-78; males: 6). On average, the proposed algorithm was able to successfully identify 79% of the SCG waveforms in systole and 68% in diastole. The simulated results show that SCG-based prediction produced less average phase error than that of ECG. It was found that the accuracy of ECG-based gating is more susceptible to increases in heart rate variability, while SCG-based gating is susceptible to high cycle to cycle variability in morphology. This pilot work of prediction using SCG waveforms enriches the framework of a comprehensive system with multiple modalities that could potentially, in real time, improve the image quality of CTA.

  1. Dysfunctional Hyperpolarization-Activated Cyclic Nucleotide-gated Ion Channels in Cardiac Diseases

    Directory of Open Access Journals (Sweden)

    Xiaoqi Zhao

    Full Text Available Abstract Hyperpolarization-activated cyclic nucleotide-gated (HCN channels are reverse voltage-dependent, and their activation depends on the hyperpolarization of the membrane and may be directly or indirectly regulated by the cyclic adenosine monophosphate (cAMP or other signal-transduction cascades. The distribution, quantity and activation states of HCN channels differ in tissues throughout the body. Evidence exhibits that HCN channels play critical roles in the generation and conduction of the electrical impulse and the physiopathological process of some cardiac diseases. They may constitute promising drug targets in the treatment of these cardiac diseases. Pharmacological treatment targeting HCN channels is of benefit to these cardiac conditions.

  2. Clinical evaluation of left ventricular wall thickness by combined technique with gated planer /sup 201/Tl image and gated cardiac pool image

    Energy Technology Data Exchange (ETDEWEB)

    Nakai, Kenji; Katsuragawa, Shigehiko; Takahashi, Tsuneo; Matsushita, Kazuo; Kawamura, Akiyoshi

    1983-11-01

    To evaluate the left ventricular (LV) wall thickness, a combined technique with gated planer 201-thallium image and gated cardiac pool image was applied to 6 patients with hypertrophic cardiomyopathy (HCM) and 4 patients with secondary hypertrophy due to hypertension (HHD) proven by electrocardiography and ultrasonic-echocardiography. Scintigraphic pattern of hypertrophy on reconstructed planer /sup 201/Tl image showed diffuse or asymmetrical apical hypertrophy in HHD, asymmetrical septal hypertrophy in HCM. It was very interesting that abnormal perfusion was shown in /sup 201/Tl image, despite symmetrical hypertrophy in echocardiography. This techniques provided useful information for evaluating the LV wall thickness and cardiac performance.

  3. Ryanodine receptor gating controls generation of diastolic calcium waves in cardiac myocytes

    Science.gov (United States)

    Petrovič, Pavol; Valent, Ivan; Cocherová, Elena; Pavelková, Jana

    2015-01-01

    The role of cardiac ryanodine receptor (RyR) gating in the initiation and propagation of calcium waves was investigated using a mathematical model comprising a stochastic description of RyR gating and a deterministic description of calcium diffusion and sequestration. We used a one-dimensional array of equidistantly spaced RyR clusters, representing the confocal scanning line, to simulate the formation of calcium sparks. Our model provided an excellent description of the calcium dependence of the frequency of diastolic calcium sparks and of the increased tendency for the production of calcium waves after a decrease in cytosolic calcium buffering. We developed a hypothesis relating changes in the propensity to form calcium waves to changes of RyR gating and tested it by simulation. With a realistic RyR gating model, increased ability of RyR to be activated by Ca2+ strongly increased the propensity for generation of calcium waves at low (0.05–0.1-µM) calcium concentrations but only slightly at high (0.2–0.4-µM) calcium concentrations. Changes in RyR gating altered calcium wave formation by changing the calcium sensitivity of spontaneous calcium spark activation and/or the average number of open RyRs in spontaneous calcium sparks. Gating changes that did not affect RyR activation by Ca2+ had only a weak effect on the propensity to form calcium waves, even if they strongly increased calcium spark frequency. Calcium waves induced by modulating the properties of the RyR activation site could be suppressed by inhibiting the spontaneous opening of the RyR. These data can explain the increased tendency for production of calcium waves under conditions when RyR gating is altered in cardiac diseases. PMID:26009544

  4. Comparative evaluation of respiratory-gated and ungated FDG-PET for target volume definition in radiotherapy treatment planning for pancreatic cancer.

    Science.gov (United States)

    Kishi, Takahiro; Matsuo, Yukinori; Nakamura, Akira; Nakamoto, Yuji; Itasaka, Satoshi; Mizowaki, Takashi; Togashi, Kaori; Hiraoka, Masahiro

    2016-08-01

    The purpose of this study was to evaluate the usefulness of respiratory-gated positron emission tomography (4D-PET) in pancreatic cancer radiotherapy treatment planning (RTTP). Fourteen patients with 18F-fluorodeoxyglucose (FDG)-avid pancreatic tumours were evaluated between December 2013 and March 2015. Two sets of volumes were contoured for the pancreatic tumour of each patient. The biological target volume in three-dimensional RTTP (BTV3D) was contoured using conventional respiratory un-gated PET. The BTV3D was then expanded using population-based margins to generate a series of internal target volume 3D (ITV3D) values. The ITV 4D (ITV4D) was contoured using 4D-PET. Each of the five phases of 4D-PET was used for 4D contouring, and the ITV4D was constructed by summing the volumes defined on the five individual 4D-PET images. The relative volumes and normalized volumetric overlap were computed between ITV3D and ITV4D. On average, the FDG-avid tumour volumes were 1.6 (range: 0.8-2.3) fold greater in the ITV4D than in the BTV3D. On average, the ITV3D values were 2.0 (range: 1.1-3.4) fold larger than the corresponding ITV4D values. The ITV generated from 4D-PET can be used to improve the accuracy or reduce normal tissue irradiation compared with conventional un-gated PET-based ITV. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  5. Subtraction imaging of the ECG gated cardiac CT

    Energy Technology Data Exchange (ETDEWEB)

    Tanegashima, K.; Fukui, M.; Hyodo, H.

    1987-05-01

    The subtracting manipulation of contrast-enhanced gated cardiac CT (GCCT) images was experimentally studied with TCT 60A - 30 type (Toshiba) for clinical use, thereby reducing the amount of contrast medium (CM). Initially the optimum relationship between the concentration of CM and its injected velocity was determined using the model of resected canine hearts and in actual dogs. The emphasized good-subtracted images were obtained when the difference of CT values was approximately 40 H.U. between cardiac cavity and myocardium. Such condition was feasible in the use of 25 % Diatrizoic acid and its injected velocity of 0.02 ml/kg/sec. Finally the reduction of the amount of CM by 1/3 became possible in clinical settings. The method is applicable to multi-slice GCCT in various heart diseases.

  6. Absolute quantitation of left ventricular wall and cavity parameters using ECG-gated PET

    DEFF Research Database (Denmark)

    Freiberg, Jacob; Hove, Jens D; Kofoed, Klaus F

    2004-01-01

    in a heart phantom and in healthy subjects. Twelve healthy men aged 64 +/- 8 years were studied by use of cine magnetic resonance imaging (MRI) and ECG-gated FDG-PET during euglycemic glucose-insulin clamp. At increasing image noise levels, the estimated cavity volume of the heart phantom was within 2 m...

  7. 18F-FDG-PET/CT Angiography for the Diagnosis of Infective Endocarditis.

    Science.gov (United States)

    Roque, A; Pizzi, M N; Cuéllar-Calàbria, H; Aguadé-Bruix, S

    2017-02-01

    This article reviews the current imaging role of 18 F-fluordeoxyglucose positron emission computed tomography ( 18 F-FDG-PET/CT) combined with cardiac CT angiography (CTA) in infective endocarditis and discusses the strengths and limitations of this technique. The diagnosis of infective endocarditis affecting prosthetic valves and intracardiac devices is challenging because echocardiography and, therefore, the modified Duke criteria have well-recognized limitations in this clinical scenario. The high sensitivity of 18 F-FDG-PET/CT for the detection of infection associated with the accurate definition of structural damage by gated cardiac CTA in a combined technique (PET/CTA) has provided a significant increase in diagnostic sensitivity for the detection of IE. PET/CTA has proven to be a useful diagnostic tool in patients with suspected infective endocarditis. The additional information provided by this technique improves diagnostic performance in prosthetic valve endocarditis when it is used in combination with the Duke criteria. The findings obtained in PET/CTA studies have been included as a major criterion in the recently updated diagnostic algorithm in infective endocarditis guidelines.

  8. Automatic intrinsic cardiac and respiratory gating from cone-beam CT scans of the thorax region

    Science.gov (United States)

    Hahn, Andreas; Sauppe, Sebastian; Lell, Michael; Kachelrieß, Marc

    2016-03-01

    We present a new algorithm that allows for raw data-based automated cardiac and respiratory intrinsic gating in cone-beam CT scans. It can be summarized in three steps: First, a median filter is applied to an initially reconstructed volume. The forward projection of this volume contains less motion information and is subtracted from the original projections. This results in new raw data that contain only moving and not static anatomy like bones, that would otherwise impede the cardiac or respiratory signal acquisition. All further steps are applied to these modified raw data. Second, the raw data are cropped to a region of interest (ROI). The ROI in the raw data is determined by the forward projection of a binary volume of interest (VOI) that includes the diaphragm for respiratory gating and most of the edge of the heart for cardiac gating. Third, the mean gray value in this ROI is calculated for every projection and the respiratory/cardiac signal is acquired using a bandpass filter. Steps two and three are carried out simultaneously for 64 or 1440 overlapping VOI inside the body for the respiratory or cardiac signal respectively. The signals acquired from each ROI are compared and the most consistent one is chosen as the desired cardiac or respiratory motion signal. Consistency is assessed by the standard deviation of the time between two maxima. The robustness and efficiency of the method is evaluated using simulated and measured patient data by computing the standard deviation of the mean signal difference between the ground truth and the intrinsic signal.

  9. Accelerated acquisition of tagged MRI for cardiac motion correction in simultaneous PET-MR: Phantom and patient studies

    International Nuclear Information System (INIS)

    Huang, Chuan; Petibon, Yoann; Ouyang, Jinsong; El Fakhri, Georges; Reese, Timothy G.; Ahlman, Mark A.; Bluemke, David A.

    2015-01-01

    Purpose: Degradation of image quality caused by cardiac and respiratory motions hampers the diagnostic quality of cardiac PET. It has been shown that improved diagnostic accuracy of myocardial defect can be achieved by tagged MR (tMR) based PET motion correction using simultaneous PET-MR. However, one major hurdle for the adoption of tMR-based PET motion correction in the PET-MR routine is the long acquisition time needed for the collection of fully sampled tMR data. In this work, the authors propose an accelerated tMR acquisition strategy using parallel imaging and/or compressed sensing and assess the impact on the tMR-based motion corrected PET using phantom and patient data. Methods: Fully sampled tMR data were acquired simultaneously with PET list-mode data on two simultaneous PET-MR scanners for a cardiac phantom and a patient. Parallel imaging and compressed sensing were retrospectively performed by GRAPPA and kt-FOCUSS algorithms with various acceleration factors. Motion fields were estimated using nonrigid B-spline image registration from both the accelerated and fully sampled tMR images. The motion fields were incorporated into a motion corrected ordered subset expectation maximization reconstruction algorithm with motion-dependent attenuation correction. Results: Although tMR acceleration introduced image artifacts into the tMR images for both phantom and patient data, motion corrected PET images yielded similar image quality as those obtained using the fully sampled tMR images for low to moderate acceleration factors (<4). Quantitative analysis of myocardial defect contrast over ten independent noise realizations showed similar results. It was further observed that although the image quality of the motion corrected PET images deteriorates for high acceleration factors, the images were still superior to the images reconstructed without motion correction. Conclusions: Accelerated tMR images obtained with more than 4 times acceleration can still provide

  10. Accelerated acquisition of tagged MRI for cardiac motion correction in simultaneous PET-MR: Phantom and patient studies

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Chuan, E-mail: chuan.huang@stonybrookmedicine.edu [Center for Advanced Medical Imaging Sciences, Division of Nuclear Medicine and Molecular Imaging, Department of Imaging, Massachusetts General Hospital, Boston, Massachusetts 02114 (United States); Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115 (United States); Departments of Radiology, Psychiatry, Stony Brook Medicine, Stony Brook, New York 11794 (United States); Petibon, Yoann [Center for Advanced Medical Imaging Sciences, Division of Nuclear Medicine and Molecular Imaging, Department of Imaging, Massachusetts General Hospital, Boston, Massachusetts 02114 (United States); Ouyang, Jinsong; El Fakhri, Georges [Center for Advanced Medical Imaging Sciences, Division of Nuclear Medicine and Molecular Imaging, Department of Imaging, Massachusetts General Hospital, Boston, Massachusetts 02114 and Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115 (United States); Reese, Timothy G. [Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115 and Martinos Center for Biomedical Imaging, Charlestown, Massachusetts 02129 (United States); Ahlman, Mark A.; Bluemke, David A. [Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Bethesda, Maryland 20892 (United States)

    2015-02-15

    Purpose: Degradation of image quality caused by cardiac and respiratory motions hampers the diagnostic quality of cardiac PET. It has been shown that improved diagnostic accuracy of myocardial defect can be achieved by tagged MR (tMR) based PET motion correction using simultaneous PET-MR. However, one major hurdle for the adoption of tMR-based PET motion correction in the PET-MR routine is the long acquisition time needed for the collection of fully sampled tMR data. In this work, the authors propose an accelerated tMR acquisition strategy using parallel imaging and/or compressed sensing and assess the impact on the tMR-based motion corrected PET using phantom and patient data. Methods: Fully sampled tMR data were acquired simultaneously with PET list-mode data on two simultaneous PET-MR scanners for a cardiac phantom and a patient. Parallel imaging and compressed sensing were retrospectively performed by GRAPPA and kt-FOCUSS algorithms with various acceleration factors. Motion fields were estimated using nonrigid B-spline image registration from both the accelerated and fully sampled tMR images. The motion fields were incorporated into a motion corrected ordered subset expectation maximization reconstruction algorithm with motion-dependent attenuation correction. Results: Although tMR acceleration introduced image artifacts into the tMR images for both phantom and patient data, motion corrected PET images yielded similar image quality as those obtained using the fully sampled tMR images for low to moderate acceleration factors (<4). Quantitative analysis of myocardial defect contrast over ten independent noise realizations showed similar results. It was further observed that although the image quality of the motion corrected PET images deteriorates for high acceleration factors, the images were still superior to the images reconstructed without motion correction. Conclusions: Accelerated tMR images obtained with more than 4 times acceleration can still provide

  11. The amount of viable and dyssynchronous myocardium is associated with response to cardiac resynchronization therapy: initial clinical results using multiparametric ECG-gated [{sup 18}F]FDG PET

    Energy Technology Data Exchange (ETDEWEB)

    Lehner, Sebastian; Uebleis, Christopher; Haug, Alexander; Bartenstein, Peter [University of Munich, Department of Nuclear Medicine, Munich (Germany); Schuessler, Franziska; Kaeaeb, Stefan; Estner, Heidi [University of Munich, Medical Department I, Munich (Germany); Van Kriekinge, Serge D.; Germano, Guido [UCLA, Cedars-Sinai Medical Center, Los Angeles and David Geffen School of Medicine, Los Angeles, CA (United States); Hacker, Marcus [Medical University of Vienna, Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Theraphy, Vienna (Austria)

    2013-12-15

    There is still a significant amount of patients who do not sufficiently respond to cardiac resynchronization therapy (CRT). Previous studies demonstrated that the amount of dyssynchronous myocardium was predictive of response to CRT. Otherwise, non-response is frequently associated with high amounts of scar tissue. The combination of these parameters might yield a more accurate prediction of response. We hypothesized that the probability of a CRT response increases with the presence of high amounts of ''viable and dyssynchronous'' myocardium. A total of 19 patients (17 male, 61 {+-} 10 years) underwent ECG-gated [{sup 18}F]fluorodeoxyglucose (FDG) myocardial positron emission tomography (PET) before CRT device implantation and were followed for 6 months. Response to CRT was defined as clinical improvement of at least one New York Heart Association (NYHA) class in combination with left ventricular (LV) ejection fraction (EF) improvement of >5 %. Twelve responders (71 %) and seven non-responders (29 %) were identified. For each patient bullseye maps of FDG uptake and phase analysis were calculated (QPS/QGS 2012, Cedars-Sinai, Los Angeles, CA, USA) and fused. Amounts of myocardium representing ''viable and synchronous'', ''scar and synchronous'', viable and dyssynchronous or ''scar and dyssynchronous'' myocardium were quantified by planimetric measurements of the fused bullseye maps. Responders by definition showed significant decrease in NYHA class and significant increase of LVEF. Furthermore, a significantly higher amount of viable and dyssynchronous myocardium was found as compared to non-responders (21 {+-} 13 % vs 6 {+-} 5 %; p < 0.05). Combined assessment of myocardial viability and LV dyssynchrony is feasible using multiparametric [{sup 18}F]FDG PET and could improve conventional response prediction criteria for CRT. (orig.)

  12. New horizons in cardiac innervation imaging. Introduction of novel 18F-labeled PET tracers

    International Nuclear Information System (INIS)

    Kobayashi, Ryohei; Chen, Xinyu; Werner, Rudolf A.; Lapa, Constantin; Javadi, Mehrbod S.; Higuchi, Takahiro

    2017-01-01

    Cardiac sympathetic nervous activity can be uniquely visualized by non-invasive radionuclide imaging techniques due to the fast growing and widespread application of nuclear cardiology in the last few years. The norepinephrine analogue 123 I-meta-iodobenzylguanidine ( 123 I-MIBG) is a single photon emission computed tomography (SPECT) tracer for the clinical implementation of sympathetic nervous imaging for both diagnosis and prognosis of heart failure. Meanwhile, positron emission tomography (PET) imaging has become increasingly attractive because of its higher spatial and temporal resolution compared to SPECT, which allows regional functional and dynamic kinetic analysis. Nevertheless, wider use of cardiac sympathetic nervous PET imaging is still limited mainly due to the demand of costly on-site cyclotrons, which are required for the production of conventional 11 C-labeled (radiological half-life, 20 min) PET tracers. Most recently, more promising 18 F-labeled (half-life, 110 min) PET radiopharmaceuticals targeting sympathetic nervous system have been introduced. These tracers optimize PET imaging and, by using delivery networks, cost less to produce. In this article, the latest advances of sympathetic nervous imaging using 18 F-labeled radiotracers along with their possible applications are reviewed. (orig.)

  13. Comparative evaluation of two commercial PET scanners, ECAT EXACT HR+ and Biograph 2, using GATE

    International Nuclear Information System (INIS)

    Karakatsanis, N.; Sakellios, N.; Tsantilas, N.X.; Dikaios, N.; Tsoumpas, C.; Lazaro, D.; Loudos, G.; Schmidtlein, C.R.; Louizi, K.; Valais, J.; Nikolopoulos, D.; Malamitsi, J.; Kandarakis, J.; Nikita, K.

    2006-01-01

    Geant4 application for tomographic emission (GATE) is a generic Monte Carlo simulation platform based on a general-purpose code GEANT4 and designed to simulate positron emission tomography (PET) and single photon emission tomography systems. Monte Carlo simulations are used in nuclear medicine to model imaging systems and develop and assess tomographic reconstruction algorithms and correction methods for improved image quantification. The purpose of this study is to validate two GATE models of the commercial available PET scanner HR+ and the PET/CT Biograph 2. The geometry of the system components has been described in GATE, including detector ring, crystal blocks, PMTs etc. The energy and spatial resolution of the scanners as given by the manufacturers have been taken into account. The GATE simulated results are compared directly to experimental data obtained using a number of NEMA NU-2-2001 performance protocols, including spatial resolution, sensitivity and scatter fraction. All the respective phantoms are precisely modeled. Furthermore, an approximate dead-time model both at the level of single and coincidence events was developed so that the simulated count rate curve can satisfactorily match the experimental count rate performance curve for each scanner In addition a software tool was developed to build the sinograms from the simulated data and import them into the software for tomographic image reconstruction where the reconstruction algorithm of FBP3DRP was applied. An agreement of less than 0.8 mm was obtained between the spatial resolution of the simulated system and the experimental results. Also the simulated scatter fraction for the NEMA NU 2-2001 scatter phantom matched the experimental results to within 3% of measured values. Finally the ratio of the simulated sensitivities with sources radially offset 0 and 10 cm from the central axis of each of the two scanners reaches an agreement of less than 1% between the simulated and experimental values. This

  14. Determinants of the response of left ventricular ejection fraction to vasodilator stress in electrocardiographically gated {sup 82}rubidium myocardial perfusion PET

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Tracy L.Y.; Merrill, Jennifer; Bengel, Frank M. [Johns Hopkins University, Department of Radiology and Radiological Sciences, Division of Nuclear Medicine, Baltimore, MD (United States); Volokh, Lana [GE Healthcare, Haifa (Israel)

    2008-02-15

    Myocardial perfusion imaging with {sup 82}Rb PET allows for ECG-gated studies to be obtained early after radiotracer injection, capturing ventricular function close to peak pharmacologic action of dipyridamole. This is different from gated SPECT and may potentially provide additional diagnostic information. We sought to identify potential correlates of the PET-derived ejection fraction response to vasodilator stress. One hundred ten consecutive patients undergoing {sup 82}Rb PET myocardial perfusion imaging during evaluation for coronary artery disease were included. Using a GE Discovery STRx PET-CT scanner, ECG-gated images (eight bins) were obtained at rest and 4 min after dipyridamole infusion, 90 s after infusion of 1,480-2,220 MBq of {sup 82}Rb. Summed rest, stress, and difference scores (SRS, SSS, and SDS) were determined using a five-point scoring system and 20-segment model. Ejection fraction was calculated using automated QGS software. Significant reversibility (SDS {>=} 4) was found in 23 patients (21%). Mean LVEF in all patients was 47 {+-} 13% at rest and 53 {+-} 13% during dipyridamole. LVEF increased in 89 patients, and decreased in 17 patients during vasodilation. The change in LVEF was inversely correlated with SDS (r = -0.26; p = 0.007). Additionally, it was inversely correlated with resting LVEF (r = -0.20; p = 0.03) and SSS (r = -0.25; p = 0.009). No significant correlations were observed with SRS, heart rate, blood pressure, age, hypertension, hypercholesterolemia, or pretest likelihood of disease. At multivariate regression analysis, SDS was an independent predictor of the change in LVEF. Gated {sup 82}Rb PET during pharmacologic stress allows for assessment of the functional response to vasodilation. The magnitude of LVEF increase is determined by stress perfusion/reversible perfusion defects. Functional response to hyperemia may thus be incorporated in future evaluations of diagnostic and prognostic algorithms based on {sup 82}Rb PET. (orig.)

  15. Initial clinical results for breath-hold CT-based processing of respiratory-gated PET acquisitions

    International Nuclear Information System (INIS)

    Fin, Loic; Daouk, Joel; Morvan, Julie; Esper, Isabelle El; Saidi, Lazhar; Meyer, Marc-Etienne; Bailly, Pascal

    2008-01-01

    Respiratory motion causes uptake in positron emission tomography (PET) images of chest structures to spread out and misregister with the CT images. This misregistration can alter the attenuation correction and thus the quantisation of PET images. In this paper, we present the first clinical results for a respiratory-gated PET (RG-PET) processing method based on a single breath-hold CT (BH-CT) acquisition, which seeks to improve diagnostic accuracy via better PET-to-CT co-registration. We refer to this method as ''CT-based'' RG-PET processing. Thirteen lesions were studied. Patients underwent a standard clinical PET protocol and then the CT-based protocol, which consists of a 10-min List Mode RG-PET acquisition, followed by a shallow end-expiration BH-CT. The respective performances of the CT-based and clinical PET methods were evaluated by comparing the distances between the lesions' centroids on PET and CT images. SUV MAX and volume variations were also investigated. The CT-based method showed significantly lower (p=0.027) centroid distances (mean change relative to the clinical method =-49%; range =-100% to 0%). This led to higher SUV MAX (mean change =+33%; range =-4% to 69%). Lesion volumes were significantly lower (p=0.022) in CT-based PET volumes (mean change =-39%: range =-74% to -1%) compared with clinical ones. A CT-based RG-PET processing method can be implemented in clinical practice with a small increase in radiation exposure. It improves PET-CT co-registration of lung lesions and should lead to more accurate attenuation correction and thus SUV measurement. (orig.)

  16. A statistical method for retrospective cardiac and respiratory motion gating of interventional cardiac x-ray images

    Energy Technology Data Exchange (ETDEWEB)

    Panayiotou, Maria, E-mail: maria.panayiotou@kcl.ac.uk; King, Andrew P.; Housden, R. James; Ma, YingLiang; Rhode, Kawal S. [Division of Imaging Sciences and Biomedical Engineering, King' s College London, London SE1 7EH (United Kingdom); Cooklin, Michael; O' Neill, Mark; Gill, Jaswinder; Rinaldi, C. Aldo [Department of Cardiology, Guy' s and St. Thomas' Hospitals NHS Foundation Trust, London SE1 7EH (United Kingdom)

    2014-07-15

    Purpose: Image-guided cardiac interventions involve the use of fluoroscopic images to guide the insertion and movement of interventional devices. Cardiorespiratory gating can be useful for 3D reconstruction from multiple x-ray views and for reducing misalignments between 3D anatomical models overlaid onto fluoroscopy. Methods: The authors propose a novel and potentially clinically useful retrospective cardiorespiratory gating technique. The principal component analysis (PCA) statistical method is used in combination with other image processing operations to make our proposed masked-PCA technique suitable for cardiorespiratory gating. Unlike many previously proposed techniques, our technique is robust to varying image-content, thus it does not require specific catheters or any other optically opaque structures to be visible. Therefore, it works without any knowledge of catheter geometry. The authors demonstrate the application of our technique for the purposes of retrospective cardiorespiratory gating of normal and very low dose x-ray fluoroscopy images. Results: For normal dose x-ray images, the algorithm was validated using 28 clinical electrophysiology x-ray fluoroscopy sequences (2168 frames), from patients who underwent radiofrequency ablation (RFA) procedures for the treatment of atrial fibrillation and cardiac resynchronization therapy procedures for heart failure. The authors established end-systole, end-expiration, and end-inspiration success rates of 97.0%, 97.9%, and 97.0%, respectively. For very low dose applications, the technique was tested on ten x-ray sequences from the RFA procedures with added noise at signal to noise ratio (SNR) values of√(5)0, √(1)0, √(8), √(6), √(5), √(2), and √(1) to simulate the image quality of increasingly lower dose x-ray images. Even at the low SNR value of √(2), representing a dose reduction of more than 25 times, gating success rates of 89.1%, 88.8%, and 86.8% were established. Conclusions: The proposed

  17. Effect of motion-induced PET-CT misalignment on cardiac function and myocardial blood flow measured using dynamic 15O-water PET

    DEFF Research Database (Denmark)

    Lubberink, Mark; Ebrahimi, M; Harms, Hans

    -CT misalignment on MBF, transmural MBF (MBFt), perfusable tissue fraction (PTF), cardiac output (CO), stroke volume (SV) and left-ventricular ejection fraction (LVEF) based on dynamic 15O-water scans. Methods: 10 patients underwent 6 min PET scans after injection of 400 MBq 15O-water at rest and during adenosine......Aim: Motion-induced PET-CT misalignment artifacts are common in myocardial blood flow (MBF) measurements with 82Rb and 13N-ammonia. For 15O-water, MBF is based on the clearance rate rather than uptake of the tracer. The clearance rate is determined by the shape of the time-activity curve, not its...... amplitude, and is thus not affected by attenuation correction errors. Hence, misalignment is hypothesized not to affect 15O-water-based MBF to any large extent, but it may affect cardiac function measures derived from 15O-water scans. The aim of the present work was to assess the effect of PET...

  18. Assessment of hypertrophic cardiomyopathy by ECG gated cardiac computed tomography

    International Nuclear Information System (INIS)

    Takeuchi, Kazuhide; Tanaka, Chujiro; Oku, Hisao

    1981-01-01

    The applicability of ECG gated cardiac computed tomography (CT) in 12 patients with hypertrophic cardiomyopathy was examined. Six of the 12 patients had hypertrophic obstructive cardiomyopathy, including one patient with mid-ventricular obstruction. Three of the 12 patients had hypertrophic non-obstructive cardiomyopathy, and three had apical hypertrophic cardiomyopathy. The diagnosis of hypertrophic cardiomyopathy was confirmed by the angiocardiogram in all patients. Cardiac CT was performed after intravenous administration of contrast media usually given as a bolus injection. The gantry was set with positive 20 0 tilt angle. In all patients with hypertrophic obstructive cardiomyopathy except for mid-ventricular obstruction, the hypertrophied interventricular septum in the basal and mid portions was observed, and the left ventricular cavity was narrowed in systole. In a patient with mid-ventricular obstruction, the marked hypertrophied interventricular septum and antero-lateral papillary muscle were observed. In diastole, the left ventricular cavity was narrow and divided into two parts. The apical cavity was completely disappeared in systole. In all patients with hypertrophic non-obstructive cardiomyopathy, the diffuse hypertrophied interventricular septum was observed in diastole. In systole, the apical portion of the left ventricular cavity was markedly narrow and antero-lateral papillary muscle was hypertrophic. In all patients with apical hypertrophic cardiomyopathy, the marked apical hypertrophy of the left ventricular wall was observed in diastole. It is concluded that ECG gated cardiac CT could estimate myocardial wall motion and thickness and differentiate the types of hypertrophic cardiomyopathy each other. (author)

  19. Noise removal using factor analysis of dynamic structures: application to cardiac gated studies.

    Science.gov (United States)

    Bruyant, P P; Sau, J; Mallet, J J

    1999-10-01

    Factor analysis of dynamic structures (FADS) facilitates the extraction of relevant data, usually with physiologic meaning, from a dynamic set of images. The result of this process is a set of factor images and curves plus some residual activity. The set of factor images and curves can be used to retrieve the original data with reduced noise using an inverse factor analysis process (iFADS). This improvement in image quality is expected because the inverse process does not use the residual activity, assumed to be made of noise. The goal of this work is to quantitate and assess the efficiency of this method on gated cardiac images. A computer simulation of a planar cardiac gated study was performed. The simulated images were added with noise and processed by the FADS-iFADS program. The signal-to-noise ratios (SNRs) were compared between original and processed data. Planar gated cardiac studies from 10 patients were tested. The data processed by FADS-iFADS were subtracted to the original data. The result of the substraction was studied to evaluate its noisy nature. The SNR is about five times greater after the FADS-iFADS process. The difference between original and processed data is noise only, i.e., processed data equals original data minus some white noise. The FADS-iFADS process is successful in the removal of an important part of the noise and therefore is a tool to improve the image quality of cardiac images. This tool does not decrease the spatial resolution (compared with smoothing filters) and does not lose details (compared with frequential filters). Once the number of factors is chosen, this method is not operator dependent.

  20. Self-gated fetal cardiac MRI with tiny golden angle iGRASP: A feasibility study.

    Science.gov (United States)

    Haris, Kostas; Hedström, Erik; Bidhult, Sebastian; Testud, Frederik; Maglaveras, Nicos; Heiberg, Einar; Hansson, Stefan R; Arheden, Håkan; Aletras, Anthony H

    2017-07-01

    To develop and assess a technique for self-gated fetal cardiac cine magnetic resonance imaging (MRI) using tiny golden angle radial sampling combined with iGRASP (iterative Golden-angle RAdial Sparse Parallel) for accelerated acquisition based on parallel imaging and compressed sensing. Fetal cardiac data were acquired from five volunteers in gestational week 29-37 at 1.5T using tiny golden angles for eddy currents reduction. The acquired multicoil radial projections were input to a principal component analysis-based compression stage. The cardiac self-gating (CSG) signal for cardiac gating was extracted from the acquired radial projections and the iGRASP reconstruction procedure was applied. In all acquisitions, a total of 4000 radial spokes were acquired within a breath-hold of less than 15 seconds using a balanced steady-state free precession pulse sequence. The images were qualitatively compared by two independent observers (on a scale of 1-4) to a single midventricular cine image from metric optimized gating (MOG) and real-time acquisitions. For iGRASP and MOG images, good overall image quality (2.8 ± 0.4 and 2.6 ± 1.3, respectively, for observer 1; 3.6 ± 0.5 and 3.4 ± 0.9, respectively, for observer 2) and cardiac diagnostic quality (3.8 ± 0.4 and 3.4 ± 0.9, respectively, for observer 1; 3.6 ± 0.5 and 3.6 ± 0.9, respectively, for observer 2) were obtained, with visualized myocardial thickening over the cardiac cycle and well-defined myocardial borders to ventricular lumen and liver/lung tissue. For iGRASP, MOG, and real time, left ventricular lumen diameter (14.1 ± 2.2 mm, 14.2 ± 1.9 mm, 14.7 ± 1.1 mm, respectively) and wall thickness (2.7 ± 0.3 mm, 2.6 ± 0.3 mm, 3.0 ± 0.4, respectively) showed agreement and no statistically significant difference was found (all P > 0.05). Images with iGRASP tended to have higher overall image quality scores compared with MOG and particularly

  1. Gated cardiac blood pool studies in arrhythmias

    International Nuclear Information System (INIS)

    Itti, R.; Casset, D.; Philippe, L.; Cosnay, P.; Fauchier, J.P.

    1988-01-01

    Biventricular phase analysis a gated blood pool studies may help to solve two fundamental questions raised by patients suffering from arrhythmias: localization of an electrical cardiac activation abnormality by means of contraction mapping and assesment of an underlying organic disease using the phase histograms and their standard deviations. Three groups of patients have been evaluated to demonstrate the usefulness of radioisotopic techniques in arrhythmias: 36 patients with a Wolff-Parkinson-White syndrom, 27 patients studied during a ventricular tachycardia attack and 32 patients suspected of arrhythmogenic ventricular dysplasia. Correlations with invasive electrophysiologic studies are presented and the diagnostic and therapeutic implications of these results are discussed [fr

  2. Gated cardiac blood pool studies in arrhythmias

    Energy Technology Data Exchange (ETDEWEB)

    Itti, R.; Casset, D.; Philippe, L.; Cosnay, P.; Fauchier, J.P.

    1988-01-01

    Biventricular phase analysis a gated blood pool studies may help to solve two fundamental questions raised by patients suffering from arrhythmias: localization of an electrical cardiac activation abnormality by means of contraction mapping and assesment of an underlying organic disease using the phase histograms and their standard deviations. Three groups of patients have been evaluated to demonstrate the usefulness of radioisotopic techniques in arrhythmias: 36 patients with a Wolff-Parkinson-White syndrom, 27 patients studied during a ventricular tachycardia attack and 32 patients suspected of arrhythmogenic ventricular dysplasia. Correlations with invasive electrophysiologic studies are presented and the diagnostic and therapeutic implications of these results are discussed.

  3. New horizons in cardiac innervation imaging. Introduction of novel {sup 18}F-labeled PET tracers

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Ryohei [University Hospital of Wuerzburg, Department of Nuclear Medicine, Wuerzburg (Germany); Nihon Medi-Physics Co., Ltd., Research Centre, Chiba (Japan); Chen, Xinyu [University Hospital of Wuerzburg, Department of Nuclear Medicine, Wuerzburg (Germany); University Hospital of Wuerzburg, Comprehensive Heart Failure Center, Wuerzburg (Germany); Werner, Rudolf A. [University Hospital of Wuerzburg, Department of Nuclear Medicine, Wuerzburg (Germany); University Hospital of Wuerzburg, Comprehensive Heart Failure Center, Wuerzburg (Germany); Johns Hopkins School of Medicine, The Russell H Morgan Department of Radiology and Radiological Sciences, Baltimore, MD (United States); Lapa, Constantin [University Hospital of Wuerzburg, Department of Nuclear Medicine, Wuerzburg (Germany); Javadi, Mehrbod S. [Johns Hopkins School of Medicine, The Russell H Morgan Department of Radiology and Radiological Sciences, Baltimore, MD (United States); Higuchi, Takahiro [University Hospital of Wuerzburg, Department of Nuclear Medicine, Wuerzburg (Germany); University Hospital of Wuerzburg, Comprehensive Heart Failure Center, Wuerzburg (Germany); National Cerebral and Cardiovascular Center, Department of Biomedical Imaging, Research Institute, Suita (Japan)

    2017-12-15

    Cardiac sympathetic nervous activity can be uniquely visualized by non-invasive radionuclide imaging techniques due to the fast growing and widespread application of nuclear cardiology in the last few years. The norepinephrine analogue {sup 123}I-meta-iodobenzylguanidine ({sup 123}I-MIBG) is a single photon emission computed tomography (SPECT) tracer for the clinical implementation of sympathetic nervous imaging for both diagnosis and prognosis of heart failure. Meanwhile, positron emission tomography (PET) imaging has become increasingly attractive because of its higher spatial and temporal resolution compared to SPECT, which allows regional functional and dynamic kinetic analysis. Nevertheless, wider use of cardiac sympathetic nervous PET imaging is still limited mainly due to the demand of costly on-site cyclotrons, which are required for the production of conventional {sup 11}C-labeled (radiological half-life, 20 min) PET tracers. Most recently, more promising {sup 18}F-labeled (half-life, 110 min) PET radiopharmaceuticals targeting sympathetic nervous system have been introduced. These tracers optimize PET imaging and, by using delivery networks, cost less to produce. In this article, the latest advances of sympathetic nervous imaging using {sup 18}F-labeled radiotracers along with their possible applications are reviewed. (orig.)

  4. Detection and compensation of organ/lesion motion using 4D-PET/CT respiratory gated acquisition techniques

    International Nuclear Information System (INIS)

    Bettinardi, Valentino; Picchio, Maria; Di Muzio, Nadia; Gianolli, Luigi; Gilardi, Maria Carla; Messa, Cristina

    2010-01-01

    Purpose: To describe the degradation effects produced by respiratory organ and lesion motion on PET/CT images and to define the role of respiratory gated (RG) 4D-PET/CT techniques to compensate for such effects. Methods: Based on the literature and on our own experience, technical recommendations and clinical indications for the use of RG 4D PET/CT have been outlined. Results: RG 4D-PET/CT techniques require a state of the art PET/CT scanner, a respiratory monitoring system and dedicated acquisition and processing protocols. Patient training is particularly important to obtain a regular breathing pattern. An adequate number of phases has to be selected to balance motion compensation and statistical noise. RG 4D PET/CT motion free images may be clinically useful for tumour tissue characterization, monitoring patient treatment and target definition in radiation therapy planning. Conclusions: RG 4D PET/CT is a valuable tool to improve image quality and quantitative accuracy and to assess and measure organ and lesion motion for radiotherapy planning.

  5. Automatic tumour volume delineation in respiratory-gated PET images

    International Nuclear Information System (INIS)

    Gubbi, Jayavardhana; Palaniswami, Marimuthu; Kanakatte, Aparna; Mani, Nallasamy; Kron, Tomas; Binns, David; Srinivasan, Bala

    2011-01-01

    Positron emission tomography (PET) is a state-of-the-art functional imaging technique used in the accurate detection of cancer. The main problem with the tumours present in the lungs is that they are non-stationary during each respiratory cycle. Tumours in the lungs can get displaced up to 2.5 cm during respiration. Accurate detection of the tumour enables avoiding the addition of extra margin around the tumour that is usually used during radiotherapy treatment planning. This paper presents a novel method to detect and track tumour in respiratory-gated PET images. The approach followed to achieve this task is to automatically delineate the tumour from the first frame using support vector machines. The resulting volume and position information from the first frame is used in tracking its motion in the subsequent frames with the help of level set (LS) deformable model. An excellent accuracy of 97% is obtained using wavelets and support vector machines. The volume calculated as a result of the machine learning (ML) stage is used as a constraint for deformable models and the tumour is tracked in the remaining seven phases of the respiratory cycle. As a result, the complete information about tumour movement during each respiratory cycle is available in relatively short time. The combination of the LS and ML approach accurately delineated the tumour volume from all frames, thereby providing a scope of using PET images towards planning an accurate and effective radiotherapy treatment for lung cancer.

  6. Low-dose respiratory-gated PET/CT: based on 30 mA tube current

    International Nuclear Information System (INIS)

    Wu Ping; Li Sijin; Zhang Yanlan; Hao Xinzhong; Qin Zhixing; Yan Min; Cheng Pengliang; Wu Zhifang

    2013-01-01

    Objective: To establish a low-dose but image-comparable respiratory-gated PET/CT (RG PET/CT) protocol based on 30 mA tube current plus other improved scanning parameters, such as the tube current, the number of respiratory phase and length of breathing cycle. Methods: Twenty-six patients with 18 F-FDG-intaking lung nodules underwent one-bed standard-dose PET/CT (120 mA, 2 min/bed) and low dose RG PET/CT (30 mA, 6 respiratory phases, 1 min/phase). The radiation dose and image quality were analyzed subsequently with signal to noise ratio (SNR) for PET and the homogeneity, noise level for CT in the water phantom respectively. Otherwise the CT images were both visual evaluated by two experienced doctors. In addition, different respiratory cycle was simulated to observe its relation with radiation dose. Results: The effective dose of low-dose RG PET/CT was 4.88∼7.69 mSv [mean (5.68±0.83) mSv]. The PET SNR showed no significance between groups. The homogeneity of 30 mA is good (< 5 HU), although noise level was high, the visual character like lobulation, speculation of lung nodule was superior in some respiratory phases. The radiation dose was positively correlated with respiratory cycle. Conclusions: The performance of low-dose RG PET/CT was comparable to those of standard-dose PET/CT based on a protocol with 30 mA tube current, 6 respiratory phases and breathing state of eupnoea. It produced a much lower radiation exposure and the image quality was enough for clinical use such as delineation of tumor active target, characterization and staging of lung nodules, etc. (authors)

  7. Myocardial viability assessment with gated SPECT Tc-99m tetrofosmin % wall thickening. Comparison with F-18 FDG-PET

    International Nuclear Information System (INIS)

    Maruyama, Atsushi; Hasegawa, Shinji; Paul, A.K.; Xiuli, M.; Yoshioka, Jun; Maruyama, Kaoru; Hori, Masatsugu; Nishimura, Tsunehiko

    2002-01-01

    This study was designed to assess the value of gated SPECT Tc-99m-tetrofosmin (TF) wall thickening (WT) in addition to TF exercise (Ex)/rest myocardial SPECT, in comparison with F-18 fluorodeoxyglucose (FDG)-PET. The study population consisted of 33 patients with old myocardial infarction (27 men and 6 women; mean age, 62±8 years old). All patients underwent Ex/rest TF SPECT and glucose loading FDG-PET. Polar map images of Ex/rest TF were generated and divided into 24 segments for further analysis. We classified LV segments according to the exercise-rest perfusion scintigraphy. LV segments with less than 70% of the maximum TF activity on the exercise image were defined as stress-induced defects. Among these, the segments whose TF acitvity increased by 10% from exercise to rest images or exceeded 70% of the maximum uptake were defined as reversible (viable) defects. The remaining defects on the rest image were irreversible (non-viable) defect segments, and were considered for viability study on the basis of %WT. %WT was calculated according to the standard method: {(counts ES-counts ED)/ counts ED} x 100. A viable segment on gated SPECT was defined as a segment whose %WT exceeded the lower limit of the normal value (mean-SD). PET viability was defined as FDG uptake exceeding 50% of the maximum count. Among the 792 segments evaluated in the 33 patients studied, there were 689 PET viable segments. Of the 689 segments analyzed, 198 (29%) were identified as having defects on Ex images. Among these defects, 55 (8%) were reversible or partially reversible, as evidenced by rest images, and 143 (21%) were irreversible. Of the irreversible segments on Ex/rest images, 106 (15%) demonstrated no apparent WT by gated TF SPECT, whereas 37 (6%) segments with irreversible defects did have apparent WT. Overall, the sensitivity of Ex/rest TF perfusion imaging was 79%. Sensitivity was improved from 79% to 85% by combining %WT and perfusion data, but specificity was reduced from 70

  8. Accuracy and effectiveness of self-gating signals in free-breathing three-dimensional cardiac cine magnetic resonance imaging

    Science.gov (United States)

    Li, Shuo; Wang, Lei; Zhu, Yan-Chun; Yang, Jie; Xie, Yao-Qin; Fu, Nan; Wang, Yi; Gao, Song

    2016-12-01

    Conventional multiple breath-hold two-dimensional (2D) balanced steady-state free precession (SSFP) presents many difficulties in cardiac cine magnetic resonance imaging (MRI). Recently, a self-gated free-breathing three-dimensional (3D) SSFP technique has been proposed as an alternative in many studies. However, the accuracy and effectiveness of self-gating signals have been barely studied before. Since self-gating signals are crucially important in image reconstruction, a systematic study of self-gating signals and comparison with external monitored signals are needed. Previously developed self-gated free-breathing 3D SSFP techniques are used on twenty-eight healthy volunteers. Both electrocardiographic (ECG) and respiratory bellow signals are also acquired during the scan as external signals. Self-gating signal and external signal are compared by trigger and gating window. Gating window is proposed to evaluate the accuracy and effectiveness of respiratory self-gating signal. Relative deviation of the trigger and root-mean-square-deviation of the cycle duration are calculated. A two-tailed paired t-test is used to identify the difference between self-gating and external signals. A Wilcoxon signed rank test is used to identify the difference between peak and valley self-gating triggers. The results demonstrate an excellent correlation (P = 0, R > 0.99) between self-gating and external triggers. Wilcoxon signed rank test shows that there is no significant difference between peak and valley self-gating triggers for both cardiac (H = 0, P > 0.10) and respiratory (H = 0, P > 0.44) motions. The difference between self-gating and externally monitored signals is not significant (two-tailed paired-sample t-test: H = 0, P > 0.90). The self-gating signals could demonstrate cardiac and respiratory motion accurately and effectively as ECG and respiratory bellow. The difference between the two methods is not significant and can be explained. Furthermore, few ECG trigger errors

  9. Quantitative simultaneous PET-MR imaging

    Science.gov (United States)

    Ouyang, Jinsong; Petibon, Yoann; Huang, Chuan; Reese, Timothy G.; Kolnick, Aleksandra L.; El Fakhri, Georges

    2014-06-01

    Whole-body PET is currently limited by the degradation due to patient motion. Respiratory motion degrades imaging studies of the abdomen. Similarly, both respiratory and cardiac motions significantly hamper the assessment of myocardial ischemia and/or metabolism in perfusion and viability cardiac PET studies. Based on simultaneous PET-MR, we have developed robust and accurate MRI methods allowing the tracking and measurement of both respiratory and cardiac motions during abdominal or cardiac studies. Our list-mode iterative PET reconstruction framework incorporates the measured motion fields into PET emission system matrix as well as the time-dependent PET attenuation map and the position dependent point spread function. Our method significantly enhances the PET image quality as compared to conventional methods.

  10. Feasibility of deep-inspiration breath-hold PET/CT with short-time acquisition. Detectability for pulmonary lesions compared with respiratory-gated PET/CT

    International Nuclear Information System (INIS)

    Yamashita, Shozo; Yamamoto, Haruki; Hiko, Shigeaki; Horita, Akihiro; Yokoyama, Kunihiko; Onoguchi, Masahisa; Nakajima, Kenichi

    2014-01-01

    Deep-inspiration breath-hold (DIBH) positron emission tomography (PET)/CT with short-time acquisition and respiratory-gated (RG) PET/CT are performed for pulmonary lesions to reduce the respiratory motion artifacts, and to obtain more accurate standardized uptake value (SUV). DIBH PET/CT demonstrates significant advantages in terms of rapid examination, good quality of CT images and low radiation exposure. On the other hand, the image quality of DIBH PET is generally inferior to that of RG PET because of short-time acquisition resulting in poor signal-to-noise ratio. In this study, RG PET has been regarded as a gold standard, and its detectability between DIBH and RG PET studies was compared using each of the most optimal reconstruction parameters. In the phantom study, the most optimal reconstruction parameters for DIBH and RG PET were determined. In the clinical study, 19 cases were examined using each of the most optimal reconstruction parameters. In the phantom study, the most optimal reconstruction parameters for DIBH and RG PET were different. Reconstruction parameters of DIBH PET could be obtained by reducing the number of subsets for those of RG PET in the state of fixing the number of iterations. In the clinical study, high correlation in the maximum SUV was observed between DIBH and RG PET studies. The clinical result was consistent with that of the phantom study surrounded by air since most of the lesions were located in the low pulmonary radioactivity. DIBH PET/CT may be the most practical method which can be the first choice to reduce respiratory motion artifacts if the detectability of DIBH PET is equivalent with that of RG PET. Although DIBH PET may have limitations in suboptimal signal-to-noise ratio, most of the lesions surrounded by low background radioactivity could provide nearly equivalent image quality between DIBH and RG PET studies when each of the most optimal reconstruction parameters was used. (author)

  11. First experience of simultaneous PET/MRI for the early detection of cardiac involvement in patients with Anderson-Fabry disease

    Energy Technology Data Exchange (ETDEWEB)

    Nappi, Carmela; Altiero, Michele; Imbriaco, Massimo; Giudice, Caterina Anna; Spinelli, Letizia; Cuocolo, Alberto [University Federico II, Department of Advanced Biomedical Sciences, Naples (Italy); Nicolai, Emanuele; Aiello, Marco; Diomiaiuti, Claudio Tommaso [IRCCS SDN, Naples (Italy); Pisani, Antonio [University Federico II, Department of Public Health, Naples (Italy)

    2015-03-26

    Anderson-Fabry disease (AFD) is an X-linked lysosomal storage disorder associated with severe multiorgan dysfunction and premature death. Early diagnosis and treatment strategies play a key role in patient outcome. We investigated the potential role of hybrid PET/MR imaging in the assessment of early cardiac involvement in AFD patients. Thirteen AFD patients without cardiac symptoms and with normal left ventricular function underwent simultaneous cardiac PET/MR imaging after administration of {sup 18}F-FDG. Cardiac FDG uptake was quantified by measuring the standardized uptake value in 17 myocardial segments in each subject. The coefficient of variation (COV, i.e. the standard deviation divided by the average) of the uptake of the 17 segments was calculated as an index of heterogeneity in the heart. Six patients exhibited focal late gadolinium enhancement (LGE) indicating intramyocardial fibrosis, and four of these also had positive short inversion time inversion recovery (STIR) sequences. All patients with LGE and positive STIR MR images showed focal FDG uptake in the corresponding myocardial segments indicating inflammation. Of the seven patients with negative LGE and STIR images, five showed homogeneous FDG cardiac uptake and two showed heterogeneous FDG uptake. The COV was significantly greater in patients with focal FDG uptake (0.25 ± 0.02) than in those without (0.14 ± 0.07, p < 0.01). PET/MR imaging is clinically feasible for the early detection of cardiac involvement in patients with AFD. Further studies evaluating the role of hybrid PET/MR imaging in management of the disease in larger patient populations are warranted. (orig.)

  12. First experience of simultaneous PET/MRI for the early detection of cardiac involvement in patients with Anderson-Fabry disease

    International Nuclear Information System (INIS)

    Nappi, Carmela; Altiero, Michele; Imbriaco, Massimo; Giudice, Caterina Anna; Spinelli, Letizia; Cuocolo, Alberto; Nicolai, Emanuele; Aiello, Marco; Diomiaiuti, Claudio Tommaso; Pisani, Antonio

    2015-01-01

    Anderson-Fabry disease (AFD) is an X-linked lysosomal storage disorder associated with severe multiorgan dysfunction and premature death. Early diagnosis and treatment strategies play a key role in patient outcome. We investigated the potential role of hybrid PET/MR imaging in the assessment of early cardiac involvement in AFD patients. Thirteen AFD patients without cardiac symptoms and with normal left ventricular function underwent simultaneous cardiac PET/MR imaging after administration of 18 F-FDG. Cardiac FDG uptake was quantified by measuring the standardized uptake value in 17 myocardial segments in each subject. The coefficient of variation (COV, i.e. the standard deviation divided by the average) of the uptake of the 17 segments was calculated as an index of heterogeneity in the heart. Six patients exhibited focal late gadolinium enhancement (LGE) indicating intramyocardial fibrosis, and four of these also had positive short inversion time inversion recovery (STIR) sequences. All patients with LGE and positive STIR MR images showed focal FDG uptake in the corresponding myocardial segments indicating inflammation. Of the seven patients with negative LGE and STIR images, five showed homogeneous FDG cardiac uptake and two showed heterogeneous FDG uptake. The COV was significantly greater in patients with focal FDG uptake (0.25 ± 0.02) than in those without (0.14 ± 0.07, p < 0.01). PET/MR imaging is clinically feasible for the early detection of cardiac involvement in patients with AFD. Further studies evaluating the role of hybrid PET/MR imaging in management of the disease in larger patient populations are warranted. (orig.)

  13. Assessment of left ventricular function by thallium-201 quantitative gated cardiac SPECT

    International Nuclear Information System (INIS)

    Baba, Akira; Hano, Takuzo; Ohmori, Hisashi; Ibata, Masayo; Kawabe, Tetsuya; Kubo, Takashi; Kimura, Keizo; Nishio, Ichiro

    2002-01-01

    Present study was designed to evaluate the accuracy of the measurement of left ventricular volume by quantitative gated SPECT (QGS) software using 201 Tl and the effect of cutoff frequency of Butterworth prereconstruction filter on the calculation of volume. The RH-2 type cardiac phantom and 20 patients with ischemic heart disease were studied. Left ventricular end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (EF) were calculated by the QGS software using the various frequency of Butterworth filter. These parameters were evaluated by Simpson's method using left ventriculography (LVG). The volume of the phantom calculated by QGS was under-estimated by 14%. In the clinical study, EDV and ESV measured by QGS were smaller than those obtained from LVG by 10%. When the cutoff frequency of Butterworth filter was 0.43 cycles/cm, the values measured by QGS were best correlated with those by LVG (EDV: r=0.80, p 201 Tl quantitative gated cardiac SPECT can estimate myocardial ischemia and left ventricular function simultaneously. (author)

  14. An experimental phantom study of the effect of gadolinium-based MR contrast agents on PET attenuation coefficients and PET quantification in PET-MR imaging: application to cardiac studies.

    Science.gov (United States)

    O' Doherty, Jim; Schleyer, Paul

    2017-12-01

    Simultaneous cardiac perfusion studies are an increasing trend in PET-MR imaging. During dynamic PET imaging, the introduction of gadolinium-based MR contrast agents (GBCA) at high concentrations during a dual injection of GBCA and PET radiotracer may cause increased attenuation effects of the PET signal, and thus errors in quantification of PET images. We thus aimed to calculate the change in linear attenuation coefficient (LAC) of a mixture of PET radiotracer and increasing concentrations of GBCA in solution and furthermore, to investigate if this change in LAC produced a measurable effect on the image-based PET activity concentration when attenuation corrected by three different AC strategies. We performed simultaneous PET-MR imaging of a phantom in a static scenario using a fixed activity of 40 MBq [18 F]-NaF, water, and an increasing GBCA concentration from 0 to 66 mM (based on an assumed maximum possible concentration of GBCA in the left ventricle in a clinical study). This simulated a range of clinical concentrations of GBCA. We investigated two methods to calculate the LAC of the solution mixture at 511 keV: (1) a mathematical mixture rule and (2) CT imaging of each concentration step and subsequent conversion to LAC at 511 keV. This comparison showed that the ranges of LAC produced by both methods are equivalent with an increase in LAC of the mixed solution of approximately 2% over the range of 0-66 mM. We then employed three different attenuation correction methods to the PET data: (1) each PET scan at a specific millimolar concentration of GBCA corrected by its corresponding CT scan, (2) each PET scan corrected by a CT scan with no GBCA present (i.e., at 0 mM GBCA), and (3) a manually generated attenuation map, whereby all CT voxels in the phantom at 0 mM were replaced by LAC = 0.1 cm -1 . All attenuation correction methods (1-3) were accurate to the true measured activity concentration within 5%, and there were no trends in image

  15. Comparison of cardiac gating and refocusing pulses for correction of cerebrospinal fluid pulsation artifacts in MR images

    International Nuclear Information System (INIS)

    Modic, M.T.; Haacke, E.M.; Lenz, G.W.; Masaryk, T.; Kaufman, B.; Ross, J.S.

    1986-01-01

    This study compared cardiac gating and additional refocusing gradient pulses in combination or alone for correction of cerebrospinal fluid (CSF) pulsation artifacts in both normal volunteers and in patients with suspected spinal pathology. Refocusing pulses or cardiac gating when used alone produced a decrease in ghosting artifacts on sagittal images and reduced the nonuniformity of the CSF signal on axial images. There is improved thin-section T2 imaging of the cord with long TEs and as few as one excitation. The refocusing pulses reduced ghosting artifacts also from respiratory motion and enhanced the CSF signal with shorter TRs leading to increased CSF contrast. When used together, the results were significantly better than either alone. Refocusing schemes can be used with any TR, do not require gating, and are now routinely employed at the authors' institution

  16. Validation of cardiac 123I-MIBG scintigraphy in patients with Parkinson's disease who were diagnosed with dopamine PET

    International Nuclear Information System (INIS)

    Ishibashi, Kenji; Saito, Yuko; Murayama, Shigeo; Kanemaru, Kazutomi; Oda, Keiichi; Ishiwata, Kiichi; Ishii, Kenji; Mizusawa, Hidehiro

    2010-01-01

    The aim of this study was to evaluate the diagnostic potential of cardiac 123 I-labelled metaiodobenzylguanidine ( 123 I-MIBG) scintigraphy in idiopathic Parkinson's disease (PD). The diagnosis was confirmed by positron emission tomography (PET) imaging with 11 C-labelled 2β-carbomethoxy-3β-(4-fluorophenyl)-tropane ( 11 C-CFT) and 11 C-raclopride (together designated as dopamine PET). Cardiac 123 I-MIBG scintigraphy and dopamine PET were performed for 39 parkinsonian patients. To estimate the cardiac 123 I-MIBG uptake, heart to mediastinum (H/M) ratios in early and delayed images were calculated. On the basis of established clinical criteria and our dopamine PET findings, 24 patients were classified into the PD group and 15 into the non-PD (NPD) group. Both early and delayed images showed that the H/M ratios were significantly lower in the PD group than in the NPD group. When the optimal cut-off levels of the H/M ratio were set at 1.95 and 1.60 in the early and delayed images, respectively, by receiver-operating characteristic analysis, the sensitivity of cardiac 123 I-MIBG scintigraphy for the diagnosis of PD was 79.2 and 70.8% and the specificity was 93.3 and 93.3% in the early and delayed images, respectively. In the Hoehn and Yahr 1 and 2 PD patients, the sensitivity decreased by 69.2 and 53.8% in the early and delayed images, respectively. In early PD cases, cardiac 123 I-MIBG scintigraphy is of limited value in the diagnosis, because of its relatively lower sensitivity. However, because of its high specificity for the overall cases, cardiac 123 I-MIBG scintigraphy may assist in the diagnosis of PD in a complementary role with the dopaminergic neuroimaging. (orig.)

  17. Evaluating FDG uptake changes between pre and post therapy respiratory gated PET scans

    International Nuclear Information System (INIS)

    Aristophanous, Michalis; Yong, Yue; Yap, Jeffrey T.; Killoran, Joseph H.; Allen, Aaron M.; Berbeco, Ross I.; Chen, Aileen B.

    2012-01-01

    Purpose: Whole body (3D) and respiratory gated (4D) FDG-PET/CT scans performed pre-radiotherapy (pre-RT) and post-radiotherapy (post-RT) were analyzed to investigate the impact of 4D PET in evaluating 18F-fluorodeoxyglucose (FDG) uptake changes due to therapy, relative to traditional 3D PET. Methods and materials: 3D and 4D sequential FDG-PET/CT scans were acquired pre-RT and approximately one month post-RT for patients with non-small cell lung cancer (NSCLC). The lesions of high uptake targeted with radiotherapy were identified on the pre-RT scan of each patient. Each lesion on the 3D and each of the five phases of the 4D scan were analyzed using a region of interest (ROI). For each patient the ROIs of the pre-RT scans were used to locate the areas of initial FDG uptake on the post-RT scans following rigid registration. Post-RT ROIs were drawn and the FDG uptake was compared with that of the pre-RT scans. Results: Sixteen distinct lesions from 12 patients were identified and analyzed. Standardized uptake value (SUV) maxima were significantly higher (p-value <0.005) for the lesions as measured on the 4D compared to 3D PET. Comparison of serial pre and post-RT scans showed a mean 62% decrease in SUV with the 3D PET scan (range 36–89%), and a 67% decrease with the 4D PET scan (range 30–89%). The mean absolute difference in SUV change on 3D versus 4D scans was 4.9%, with a range 0–15% (p-value = 0.07). Conclusions: Signal recovery with 4D PET results in higher SUVs when compared to standard 3D PET. Consequently, differences in the evaluation of SUV changes between pre and post-RT plans were observed. Such difference can have a significant impact in PET-based response assessment.

  18. Hybrid cardiac imaging using PET/MRI: a joint position statement by the European Society of Cardiovascular Radiology (ESCR) and the European Association of Nuclear Medicine (EANM).

    Science.gov (United States)

    Nensa, Felix; Bamberg, Fabian; Rischpler, Christoph; Menezes, Leon; Poeppel, Thorsten D; la Fougère, Christian; Beitzke, Dietrich; Rasul, Sazan; Loewe, Christian; Nikolaou, Konstantin; Bucerius, Jan; Kjaer, Andreas; Gutberlet, Matthias; Prakken, Niek H; Vliegenthart, Rozemarijn; Slart, Riemer H J A; Nekolla, Stephan G; Lassen, Martin L; Pichler, Bernd J; Schlosser, Thomas; Jacquier, Alexis; Quick, Harald H; Schäfers, Michael; Hacker, Marcus

    2018-05-02

    Positron emission tomography (PET) and magnetic resonance imaging (MRI) have both been used for decades in cardiovascular imaging. Since 2010, hybrid PET/MRI using sequential and integrated scanner platforms has been available, with hybrid cardiac PET/MR imaging protocols increasingly incorporated into clinical workflows. Given the range of complementary information provided by each method, the use of hybrid PET/MRI may be justified and beneficial in particular clinical settings for the evaluation of different disease entities. In the present joint position statement, we critically review the role and value of integrated PET/MRI in cardiovascular imaging, provide a technical overview of cardiac PET/MRI and practical advice related to the cardiac PET/MRI workflow, identify cardiovascular applications that can potentially benefit from hybrid PET/MRI, and describe the needs for future development and research. In order to encourage its wide dissemination, this article is freely accessible on the European Radiology and European Journal of Hybrid Imaging web sites. • Studies and case-reports indicate that PET/MRI is a feasible and robust technology. • Promising fields of application include a variety of cardiac conditions. • Larger studies are required to demonstrate its incremental and cost-effective value. • The translation of novel radiopharmaceuticals and MR-sequences will provide exciting new opportunities.

  19. Low-dose dobutamine stress gated SPET for identification of viable myocardium: comparison with stress-rest perfusion SPET and PET

    International Nuclear Information System (INIS)

    Yoshinaga, Keiichiro; Tamaki, Nagara; Katoh, Chietsugu; Kuge, Yuji; Noriyasu, Kazuyuki; Yamada, Satoshi; Ito, Yoshinori; Kohya, Tetsuro; Kitabatake, Akira; Kawai, Yuko

    2002-01-01

    The detection of viable myocardium is important for the prediction of functional recovery after revascularisation. However, a fixed perfusion defect often includes viable myocardium, and perfusion imaging then underestimates myocardial viability. We previously reported that low-dose dobutamine stress gated single-photon emission tomography (SPET) provides similar findings to dobutamine stress echocardiography in the assessment of myocardial viability. The present study investigated whether low-dose dobutamine stress gated SPET is of additional value as compared with stress-rest technetium-99m tetrofosmin SPET for the detection of myocardial viability. Standard stress-rest perfusion SPET, low-dose dobutamine stress gated SPET and fluorine-18 fluorodeoxyglucose positron emission tomography (FDG PET) were studied in 23 patients (mean age 67±7.6 years) with previous myocardial infarction. Twenty-one of them were successfully studied with each technique. FDG PET viability (FDG uptake ≥50%) was employed as the gold standard. One-day stress-rest 99m Tc-tetrofosmin myocardial SPET was performed. After the resting study, gated SPET was acquired following infusion of 7.5 μg kg -1 min -1 of dobutamine. Left ventricular wall motion in 16 segments was assessed by cine mode display using a four-point scale. Myocardial viability was considered present when there was improvement by one point. Of a total of 336 segments analysed, 53 had persistent defects on stress-rest perfusion SPET. FDG viability was seen in 16 of 17 dobutamine-responsive segments, but in only 11 of 36 dobutamine non-responsive segments (P<0.01). Thus, in the segments with persistent defects, viability findings on low-dose dobutamine stress gated SPET were concordant with those on FDG PET in 77% of segments (kappa value =0.55). For the detection of FDG-viable myocardium, the combination of stress-rest perfusion SPET and low-dose dobutamine stress gated SPET achieved a better sensitivity than stress

  20. Initial validation of 4D-model for a clinical PET scanner using the Monte Carlo code gate

    International Nuclear Information System (INIS)

    Vieira, Igor F.; Lima, Fernando R.A.; Gomes, Marcelo S.; Vieira, Jose W.; Pacheco, Ludimila M.; Chaves, Rosa M.

    2011-01-01

    Building exposure computational models (ECM) of emission tomography (PET and SPECT) currently has several dedicated computing tools based on Monte Carlo techniques (SimSET, SORTEO, SIMIND, GATE). This paper is divided into two steps: (1) using the dedicated code GATE (Geant4 Application for Tomographic Emission) to build a 4D model (where the fourth dimension is the time) of a clinical PET scanner from General Electric, GE ADVANCE, simulating the geometric and electronic structures suitable for this scanner, as well as some phenomena 4D, for example, rotating gantry; (2) the next step is to evaluate the performance of the model built here in the reproduction of test noise equivalent count rate (NEC) based on the NEMA Standards Publication NU protocols 2-2007 for this tomography. The results for steps (1) and (2) will be compared with experimental and theoretical values of the literature showing actual state of art of validation. (author)

  1. Initial validation of 4D-model for a clinical PET scanner using the Monte Carlo code gate

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Igor F.; Lima, Fernando R.A.; Gomes, Marcelo S., E-mail: falima@cnen.gov.b [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Vieira, Jose W.; Pacheco, Ludimila M. [Instituto Federal de Educacao, Ciencia e Tecnologia (IFPE), Recife, PE (Brazil); Chaves, Rosa M. [Instituto de Radium e Supervoltagem Ivo Roesler, Recife, PE (Brazil)

    2011-07-01

    Building exposure computational models (ECM) of emission tomography (PET and SPECT) currently has several dedicated computing tools based on Monte Carlo techniques (SimSET, SORTEO, SIMIND, GATE). This paper is divided into two steps: (1) using the dedicated code GATE (Geant4 Application for Tomographic Emission) to build a 4D model (where the fourth dimension is the time) of a clinical PET scanner from General Electric, GE ADVANCE, simulating the geometric and electronic structures suitable for this scanner, as well as some phenomena 4D, for example, rotating gantry; (2) the next step is to evaluate the performance of the model built here in the reproduction of test noise equivalent count rate (NEC) based on the NEMA Standards Publication NU protocols 2-2007 for this tomography. The results for steps (1) and (2) will be compared with experimental and theoretical values of the literature showing actual state of art of validation. (author)

  2. Extracting a respiratory signal from raw dynamic PET data that contain tracer kinetics.

    Science.gov (United States)

    Schleyer, P J; Thielemans, K; Marsden, P K

    2014-08-07

    Data driven gating (DDG) methods provide an alternative to hardware based respiratory gating for PET imaging. Several existing DDG approaches obtain a respiratory signal by observing the change in PET-counts within specific regions of acquired PET data. Currently, these methods do not allow for tracer kinetics which can interfere with the respiratory signal and introduce error. In this work, we produced a DDG method for dynamic PET studies that exhibit tracer kinetics. Our method is based on an existing approach that uses frequency-domain analysis to locate regions within raw PET data that are subject to respiratory motion. In the new approach, an optimised non-stationary short-time Fourier transform was used to create a time-varying 4D map of motion affected regions. Additional processing was required to ensure that the relationship between the sign of the respiratory signal and the physical direction of movement remained consistent for each temporal segment of the 4D map. The change in PET-counts within the 4D map during the PET acquisition was then used to generate a respiratory curve. Using 26 min dynamic cardiac NH3 PET acquisitions which included a hardware derived respiratory measurement, we show that tracer kinetics can severely degrade the respiratory signal generated by the original DDG method. In some cases, the transition of tracer from the liver to the lungs caused the respiratory signal to invert. The new approach successfully compensated for tracer kinetics and improved the correlation between the data-driven and hardware based signals. On average, good correlation was maintained throughout the PET acquisitions.

  3. Prediction of cardiac sympathetic nerve activity and cardiac functional outcome after treatment in patients with dilated cardiomyopathy. Examination using dobutamine gated blood pool scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Kasama, Shu; Toyama, Takuji; Iwasaki, Tsutomu; Suzuki, Tadashi [Gunma Univ., Maebashi (Japan). School of Medicine; Hoshizaki, Hiroshi; Oshima, Shigeru; Taniguchi, Koichi; Nagai, Ryozo

    2000-07-01

    This study evaluated whether dobutamine gated blood pool scintigraphy can predict improvement of cardiac sympathetic nerve activity and cardiac function. Sixteen patients (10 men and 6 women, mean age 59{+-}13 years) with dilated cardiomyopathy underwent dobutamine gated blood pool scintigraphy to measure left ventricular ejection fraction (LVEF) using tracer at 0, 5, 10 and 15 {mu}g/kg/min before treatment. Patients were divided into good responders (LVEF increase {>=}15%) 8 patients (GR Group) and poor responders (LVEF increase <15%) 8 patients (PR Group) after treatment with {beta}-blocker or amiodarone with a background treatment of digitalis, diuretics and angiotensin converting enzyme inhibitor. I-123 metaiodobenzylguanidine (MIBG) imaging to evaluate cardiac sympathetic nerve activity and echocardiography were performed before and at one year after treatment. MIBG imaging was obtained 4 hours after tracer injection, and the heart/mediastinum count ratio (H/M ratio) calculated from the anterior planar image and the total defect score (TDS) from the single photon emission computed tomography image. LVEF and left ventricular endo-diastolic dimension (LVDd) were measured by echocardiography and New York Heart Association (NYHA) functional class was evaluated. The GR Group showed TDS decreased from 28{+-}6 to 17{+-}12 (p<0.05), H/M ratio increased from 1.79{+-}0.26 to 2.07{+-}0.32 (p<0.05), LVEF increased from 29{+-}8% to 48{+-}10% (p<0.01), and LVDd decreased from 65{+-}4 mm to 58{+-}5 mm (p<0.05). In contrast, the PR group showed no significant changes in TDS. H/M ratio, LVEF and LVDd. NYHA functional class improved in both groups. The improvement was better in the GR Group than in the PR group. Dobutamine gated blood pool scintigraphy is useful to predict the improvement of the cardiac sympathetic nerve activity and cardiac function, and symptoms after treatment in patients with dilated cardiomyopathy. (author)

  4. Is metal artefact reduction mandatory in cardiac PET/CT imaging in the presence of pacemaker and implantable cardioverter defibrillator leads?

    Energy Technology Data Exchange (ETDEWEB)

    Ghafarian, Pardis [Shahid Beheshti University, Department of Radiation Medicine, Tehran (Iran, Islamic Republic of); Geneva University Hospital, Division of Nuclear Medicine, Geneva 4 (Switzerland); Tehran University of Medical Sciences, Research Center for Science and Technology in Medicine, Tehran (Iran, Islamic Republic of); Aghamiri, S.M.R. [Shahid Beheshti University, Department of Radiation Medicine, Tehran (Iran, Islamic Republic of); Ay, Mohammad R. [Tehran University of Medical Sciences, Research Center for Science and Technology in Medicine, Tehran (Iran, Islamic Republic of); Tehran University of Medical Sciences, Department of Medical Physics and Biomedical Engineering, Tehran (Iran, Islamic Republic of); Tehran University of Medical Sciences, Research Institute for Nuclear Medicine, Tehran (Iran, Islamic Republic of); Rahmim, Arman [Johns Hopkins University, Department of Radiology, Baltimore, MD (United States); Schindler, Thomas H. [Geneva University, Cardiovascular Center, Nuclear Cardiology, Geneva (Switzerland); Ratib, Osman [Geneva University Hospital, Division of Nuclear Medicine, Geneva 4 (Switzerland); Zaidi, Habib [Geneva University Hospital, Division of Nuclear Medicine, Geneva 4 (Switzerland); Geneva University, Geneva Neuroscience Center, Geneva (Switzerland)

    2011-02-15

    Cardiac PET/CT imaging is often performed in patients with pacemakers and implantable cardioverter defibrillator (ICD) leads. However, metallic implants usually produce artefacts on CT images which might propagate to CT-based attenuation-corrected (CTAC) PET images. The impact of metal artefact reduction (MAR) for CTAC of cardiac PET/CT images in the presence of pacemaker, ICD and ECG leads was investigated using both qualitative and quantitative analysis in phantom and clinical studies. The study included 14 patients with various leads undergoing perfusion and viability examinations using dedicated cardiac PET/CT protocols. The PET data were corrected for attenuation using both artefactual CT images and CT images corrected using the MAR algorithm. The severity and magnitude of metallic artefacts arising from these leads were assessed on both linear attenuation coefficient maps ({mu}-maps) and attenuation-corrected PET images. CT and PET emission data were obtained using an anthropomorphic thorax phantom and a dedicated heart phantom made in-house incorporating pacemaker and ICD leads attached at the right ventricle of the heart. Volume of interest-based analysis and regression plots were performed for regions related to the lead locations. Bull's eye view analysis was also performed on PET images corrected for attenuation with and without the MAR algorithm. In clinical studies, the visual assessment of PET images by experienced physicians and quantitative analysis did not reveal erroneous interpretation of the tracer distribution or significant differences when PET images were corrected for attenuation with and without MAR. In phantom studies, the mean differences between tracer uptake obtained without and with MAR were 10.16{+-}2.1% and 6.86{+-}2.1% in the segments of the heart in the vicinity of metallic ICD or pacemaker leads, and were 4.43{+-}0.5% and 2.98{+-}0.5% in segments far from the leads. Although the MAR algorithm was able to effectively improve

  5. Design and development of a new pulsating cardiac coronary phantom for ECG-gated CT and its experimental characteristics

    International Nuclear Information System (INIS)

    Shen, Yun; Sato, Munekuni; Kimura, Fumiko; Jinzaki, Masahiro; Kuribayashi, Sachio; Horiguchi, Jun; Ito, Katsuhide

    2005-01-01

    The optimal pulsating cardiac phantom is an important tool for the evaluation of cardiac images and cardiac applications on electrocardiogram (ECG)-gated multidetector-row CT (MDCT). The purpose of this study was to demonstrate the design and fabrication of the pulsating cardiac coronary phantom. The newly developed pulsating cardiac coronary phantom has the following five key advantages: a driver component that uses only one servomotor to move the phantom in three dimensions (X, Y, and Z directions) with 16 presets of different heart types (heartbeat: 0-120 bpm; ejection fraction: 0-90%); versatile pumping and filling phases to simulate a real heart in a cardiac cycle can be incorporated into the driver sequence including shift of patient heartbeat or irregular pulse (maximum: 200 different heart waves in one scan); a cardiac coronary component constituted of an acrylic/silicon/rubber tube (2-6 mm inner diameter) with stent/in-stent restenosis/stenosis/soft plaque/calcification parts and maximum 16 coronary arteries that can be attached to the phantom in the same scan; the complete phantom can be submerged in a tank to simulate the heart and its surrounding tissues; ECG gating can be from interior trigger and exterior trigger. It has been confirmed that the developed pulsating cardiac phantom is very useful to quantitatively assess imaging of the heart and coronary arteries during phantom experiments. (author)

  6. Validation of measurements of Fourier phase and amplitude analysis of technetium99 gated cardiac scans using artificial hearts

    International Nuclear Information System (INIS)

    Yiannikas, J.; Takatani, S.; MacIntyre, W.J.; Underwood, D.A.; Cook, S.A.; Go, R.T.; Napoli, C.; Nose, Y.

    1982-01-01

    The use of artificial hearts, developed for total heart replacement programs, allows assessment of the accuracy of measuring the first Fourier component phase and amplitude when applied to gated cardiac technetium 99 scans. In the extreme example of asynchrony of ventricular contraction in coronary artery disease that of ventricular aneurysms, the first Fourier component measurements of amplitude were highly correlated to volume increases suggesting that the calculated amplitude accurately reflects volume changes. The calculated asynchrony using Fourier analysis of the gated technetium 99 studies of two artificial hearts was highly accurate when compared to the predetermined calculation of phase angle difference and hence degree of asynchrony. The studies suggest that measurement of phase and amplitude using the first Fourier component of time-activity waves of gated cardiac technetium 99 studies accurately measure degree of asynchrony and volume changes respectively

  7. Assessment of left ventricular function by thallium-201 quantitative gated cardiac SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Baba, Akira; Hano, Takuzo; Ohmori, Hisashi; Ibata, Masayo; Kawabe, Tetsuya; Kubo, Takashi; Kimura, Keizo; Nishio, Ichiro [Wakayama Medical Coll. (Japan)

    2002-02-01

    Present study was designed to evaluate the accuracy of the measurement of left ventricular volume by quantitative gated SPECT (QGS) software using {sup 201}Tl and the effect of cutoff frequency of Butterworth prereconstruction filter on the calculation of volume. The RH-2 type cardiac phantom and 20 patients with ischemic heart disease were studied. Left ventricular end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (EF) were calculated by the QGS software using the various frequency of Butterworth filter. These parameters were evaluated by Simpson's method using left ventriculography (LVG). The volume of the phantom calculated by QGS was under-estimated by 14%. In the clinical study, EDV and ESV measured by QGS were smaller than those obtained from LVG by 10%. When the cutoff frequency of Butterworth filter was 0.43 cycles/cm, the values measured by QGS were best correlated with those by LVG (EDV: r=0.80, p<0.001; ESV: r=0.86, p<0.001; EF: r=0.80, p<0.001). These data suggest that {sup 201}Tl quantitative gated cardiac SPECT can estimate myocardial ischemia and left ventricular function simultaneously. (author)

  8. Quantitation of cardiac sympathetic innervation in rabbits using 11C-hydroxyephedrine PET: relation to 123I-MIBG uptake

    International Nuclear Information System (INIS)

    Nomura, Yusuke; Kajinami, Kouji; Matsunari, Ichiro; Takamatsu, Hiroyuki; Murakami, Yoshihiro; Matsuya, Takahiro; Chen, Wei-Ping; Taki, Junichi; Nakajima, Kenichi; Nekolla, Stephan G.

    2006-01-01

    Although 11 C-hydroxyephedrine ( 11 C-HED) PET is used to map cardiac sympathetic innervation, no studies have shown the feasibility of quantitation of 11 C-HED PET in small- to medium-sized animals. Furthermore, its relation to 123 I-MIBG uptake, the most widely used sympathetic nervous tracer, is unknown. The aims of this study were to establish in vivo sympathetic nerve imaging in rabbits using 11 C-HED PET, and to compare the retention of 11 C-HED with that of 123 I-MIBG. Twelve rabbits were assigned to three groups; control (n=4), chemical denervation by 6-hydroxydopamine (6-OHDA) (n=4) and reserpine treated to inhibit vesicular uptake (n=4). After simultaneous injection of 11 C-HED and 123 I-MIBG, all animals underwent dynamic 11 C-HED PET for 40 min with arterial blood sampling. The 11 C-HED retention fraction and normalised 11 C-HED activity measured by tissue sampling were compared with those measured by PET. Both the 11 C-HED retention fraction and the normalised 11 C-HED activity measured by PET correlated closely with those measured by tissue sampling (R=0.96027, p 11 C-HED and 123 I-MIBG. Reserpine pretreatment reduced 11 C-HED retention by 50%, but did not reduce 123 I-MIBG retention at 40 min after injection. Non-invasive quantitation of cardiac sympathetic innervation using 11 C-HED PET is feasible and gives reliable estimates of cardiac sympathetic innervation in rabbits. Additionally, although both 11 C-HED and 123 I-MIBG are specific for sympathetic neurons, 11 C-HED may be more specific for intravesicular uptake than 123 I-MIBG in some situations, such as that seen in reserpine pretreatment. (orig.)

  9. TU-G-BRA-08: BEST IN PHYSICS (JOINT IMAGING-THERAPY): Hybrid PET-MRI Imaging of Acute Radiation Induced Cardiac Toxicity

    International Nuclear Information System (INIS)

    El-Sherif, O; Xhaferllari, I; Gaede, S; Sykes, J; Butler, J; Wisenberg, G; Prato, F

    2015-01-01

    Purpose: To identify the presence of low-dose radiation induced cardiac toxicity in a canine model using hybrid positron emission tomography (PET) and magnetic resonance imaging (MRI). Methods: Research ethics board approval was obtained for a longitudinal imaging study of 5 canines after cardiac irradiation. Animals were imaged at baseline, 1 week post cardiac irradiation, and 1 month post cardiac irradiation using a hybrid PET- MRI system (Biograph mMR, Siemens Healthcare). The imaging protocol was designed to assess acute changes in myocardial perfusion and inflammation. Myocardial perfusion imaging was performed using N13-ammonia tracer followed by a dynamic PET acquisition scan. A compartmental tracer kinetic model was used for absolute perfusion quantification. Myocardial inflammation imaging was performed using F18-fluorodeoxyglucose (FDG) tracer. The standard uptake value (SUV) over a region encompassing the whole heart was used to compare FDG scans. All animals received a simulation CT scan (GE Medical Systems) for radiation treatment planning. Radiation treatment plans were created using the Pinncale3 treatment planning system (Philips Radiation Oncology Systems) and designed to resemble the typical cardiac exposure during left-sided breast cancer radiotherapy. Cardiac irradiations were performed in a single fraction using a TrueBeam linear accelerator (Varian Medical Systems). Results: The delivered dose (mean ± standard deviation) to heart was 1.8±0.2 Gy. Reductions in myocardial stress perfusion relative to baseline were observed in 2 of the 5 animals 1 month post radiation. A global inflammatory response 1 month post radiation was observed in 4 of the 5 animals. The calculated SUV at 1 month post radiation was significantly higher (p=0.05) than the baseline SUV. Conclusion: Low doses of cardiac irradiation (< 2 Gy) may lead to myocardial perfusion defects and a global inflammatory response that can be detectable as early as 1 month post irradiation

  10. TU-G-BRA-08: BEST IN PHYSICS (JOINT IMAGING-THERAPY): Hybrid PET-MRI Imaging of Acute Radiation Induced Cardiac Toxicity

    Energy Technology Data Exchange (ETDEWEB)

    El-Sherif, O; Xhaferllari, I; Gaede, S [Western Univeristy, London, ON (United Kingdom); London Regional Cancer Program, London, ON (United Kingdom); Sykes, J; Butler, J [Lawson Health Research Institute, London, ON (United Kingdom); Wisenberg, G; Prato, F [Western Univeristy, London, ON (United Kingdom); Lawson Health Research Institute, London, ON (United Kingdom)

    2015-06-15

    Purpose: To identify the presence of low-dose radiation induced cardiac toxicity in a canine model using hybrid positron emission tomography (PET) and magnetic resonance imaging (MRI). Methods: Research ethics board approval was obtained for a longitudinal imaging study of 5 canines after cardiac irradiation. Animals were imaged at baseline, 1 week post cardiac irradiation, and 1 month post cardiac irradiation using a hybrid PET- MRI system (Biograph mMR, Siemens Healthcare). The imaging protocol was designed to assess acute changes in myocardial perfusion and inflammation. Myocardial perfusion imaging was performed using N13-ammonia tracer followed by a dynamic PET acquisition scan. A compartmental tracer kinetic model was used for absolute perfusion quantification. Myocardial inflammation imaging was performed using F18-fluorodeoxyglucose (FDG) tracer. The standard uptake value (SUV) over a region encompassing the whole heart was used to compare FDG scans. All animals received a simulation CT scan (GE Medical Systems) for radiation treatment planning. Radiation treatment plans were created using the Pinncale3 treatment planning system (Philips Radiation Oncology Systems) and designed to resemble the typical cardiac exposure during left-sided breast cancer radiotherapy. Cardiac irradiations were performed in a single fraction using a TrueBeam linear accelerator (Varian Medical Systems). Results: The delivered dose (mean ± standard deviation) to heart was 1.8±0.2 Gy. Reductions in myocardial stress perfusion relative to baseline were observed in 2 of the 5 animals 1 month post radiation. A global inflammatory response 1 month post radiation was observed in 4 of the 5 animals. The calculated SUV at 1 month post radiation was significantly higher (p=0.05) than the baseline SUV. Conclusion: Low doses of cardiac irradiation (< 2 Gy) may lead to myocardial perfusion defects and a global inflammatory response that can be detectable as early as 1 month post irradiation

  11. Small animal simultaneous PET/MRI: initial experiences in a 9.4 T microMRI

    Energy Technology Data Exchange (ETDEWEB)

    Maramraju, Sri Harsha; Ravindranath, Bosky; Vaska, Paul; Schlyer, David J [Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY (United States); Smith, S David; Schulz, Daniela [Medical Department, Brookhaven National Laboratory, Upton, NY (United States); Junnarkar, Sachin S; Rescia, Sergio [Instrumentation Division, Brookhaven National Laboratory, Upton, NY (United States); Stoll, Sean; Purschke, Martin L; Woody, Craig L [Physics Department, Brookhaven National Laboratory, Upton, NY (United States); Southekal, Sudeepti [Brigham and Women' s Hospital, Boston, MA (United States); Pratte, Jean-Francois, E-mail: schlyer@bnl.gov [Universite de Sherbrooke, Sherbrooke, Quebec (Canada)

    2011-04-21

    We developed a non-magnetic positron-emission tomography (PET) device based on the rat conscious animal PET that operates in a small-animal magnetic resonance imaging (MRI) scanner, thereby enabling us to carry out simultaneous PET/MRI studies. The PET detector comprises 12 detector blocks, each being a 4 x 8 array of lutetium oxyorthosilicate crystals (2.22 x 2.22 x 5 mm{sup 3}) coupled to a matching non-magnetic avalanche photodiode array. The detector blocks, housed in a plastic case, form a 38 mm inner diameter ring with an 18 mm axial extent. Custom-built MRI coils fit inside the positron-emission tomography (PET) device, operating in transceiver mode. The PET insert is integrated with a Bruker 9.4 T 210 mm clear-bore diameter MRI scanner. We acquired simultaneous PET/MR images of phantoms, of in vivo rat brain, and of cardiac-gated mouse heart using [{sup 11}C]raclopride and 2-deoxy-2-[{sup 18}F]fluoro-d-glucose PET radiotracers. There was minor interference between the PET electronics and the MRI during simultaneous operation, and small effects on the signal-to-noise ratio in the MR images in the presence of the PET, but no noticeable visual artifacts. Gradient echo and high-duty-cycle spin echo radio frequency (RF) pulses resulted in a 7% and a 28% loss in PET counts, respectively, due to high PET counts during the RF pulses that had to be gated out. The calibration of the activity concentration of PET data during MR pulsing is reproducible within less than 6%. Our initial results demonstrate the feasibility of performing simultaneous PET and MRI studies in adult rats and mice using the same PET insert in a small-bore 9.4 T MRI.

  12. PET imaging of human cardiac opioid receptors

    Energy Technology Data Exchange (ETDEWEB)

    Villemagne, Patricia S.R.; Dannals, Robert F. [Department of Radiology, The Johns Hopkins University School of Medicine, 605 N Caroline St., Baltimore, Maryland (United States); Department of Environmental Health Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland (United States); Ravert, Hayden T. [Department of Radiology, The Johns Hopkins University School of Medicine, 605 N Caroline St., Baltimore, Maryland (United States); Frost, James J. [Department of Radiology, The Johns Hopkins University School of Medicine, 605 N Caroline St., Baltimore, Maryland (United States); Department of Environmental Health Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland (United States); Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland (United States)

    2002-10-01

    The presence of opioid peptides and receptors and their role in the regulation of cardiovascular function has been previously demonstrated in the mammalian heart. The aim of this study was to image {mu} and {delta} opioid receptors in the human heart using positron emission tomography (PET). Five subjects (three females, two males, 65{+-}8 years old) underwent PET scanning of the chest with [{sup 11}C]carfentanil ([{sup 11}C]CFN) and [{sup 11}C]-N-methyl-naltrindole ([{sup 11}C]MeNTI) and the images were analyzed for evidence of opioid receptor binding in the heart. Either [{sup 11}C]CFN or [{sup 11}C]MeNTI (20 mCi) was injected i.v. with subsequent dynamic acquisitions over 90 min. For the blocking studies, either 0.2 mg/kg or 1 mg/kg of naloxone was injected i.v. 5 min prior to the injection of [{sup 11}C]CFN and [{sup 11}C]MeNTI, respectively. Regions of interest were placed over the left ventricle, left ventricular chamber, lung and skeletal muscle. Graphical analysis demonstrated average baseline myocardial binding potentials (BP) of 4.37{+-}0.91 with [{sup 11}C]CFN and 3.86{+-}0.60 with [{sup 11}C]MeNTI. Administration of 0.2 mg/kg naloxone prior to [{sup 11}C]CFN produced a 25% reduction in BP in one subject in comparison with baseline values, and a 19% decrease in myocardial distribution volume (DV). Administration of 1 mg/kg of naloxone before [{sup 11}C]MeNTI in another subject produced a 14% decrease in BP and a 21% decrease in the myocardial DV. These results demonstrate the ability to image these receptors in vivo by PET. PET imaging of cardiac opioid receptors may help to better understand their role in cardiovascular pathophysiology and the effect of abuse of opioids and drugs on heart function. (orig.)

  13. Comparison of {sup 18}F-fluorodeoxyglucose positron emission tomography (FDG PET) and cardiac magnetic resonance (CMR) in corticosteroid-naive patients with conduction system disease due to cardiac sarcoidosis

    Energy Technology Data Exchange (ETDEWEB)

    Ohira, Hiroshi; Birnie, David H.; Mc Ardle, Brian; Dick, Alexander; Klein, Ran; Renaud, Jennifer; DeKemp, Robert A.; Davies, Ross; Hessian, Renee; Liu, Peter; Nery, Pablo B. [University of Ottawa Heart Institute, Molecular Function and Imaging Program, National Cardiac PET Centre, Ottawa, ON (Canada); University of Ottawa Heart Institute, Arrhythmia Service, Division of Cardiology, Department of Medicine, Ottawa, ON (Canada); Pena, Elena; Dennie, Carole [The Ottawa Hospital, Medical Imaging Department, Ottawa, ON (Canada); University of Ottawa, Department of Radiology, Ottawa, ON (Canada); Bernick, Jordan; Wells, George A. [University of Ottawa Heart Institute, Cardiovascular Research Methods Center, Ottawa, ON (Canada); Leung, Eugene [The Ottawa Hospital, Division of Nuclear Medicine, Department of Medicine, Ottawa, Ontario (Canada); Yoshinaga, Keiichiro [Hokkaido University School of Medicine, Department of Molecular Imaging, Hokkaido (Japan); Tsujino, Ichizo; Sato, Takahiro; Nishimura, Masaharu [Hokkaido University School of Medicine, First Department of Medicine, Hokkaido (Japan); Manabe, Osamu; Tamaki, Nagara [Hokkaido University School of Medicine, Department of Nuclear Medicine, Hokkaido (Japan); Oyama-Manabe, Noriko [Hokkaido University Hospital, Diagnostic and Interventional Radiology, Hokkaido (Japan); Ruddy, Terrence D.; Beanlands, Rob S.B. [University of Ottawa Heart Institute, Molecular Function and Imaging Program, National Cardiac PET Centre, Ottawa, ON (Canada); University of Ottawa Heart Institute, Arrhythmia Service, Division of Cardiology, Department of Medicine, Ottawa, ON (Canada); The Ottawa Hospital, Medical Imaging Department, Ottawa, ON (Canada); University of Ottawa, Department of Radiology, Ottawa, ON (Canada); The Ottawa Hospital, Division of Nuclear Medicine, Department of Medicine, Ottawa, Ontario (Canada); Chow, Benjamin J.W. [University of Ottawa Heart Institute, Molecular Function and Imaging Program, National Cardiac PET Centre, Ottawa, ON (Canada); University of Ottawa Heart Institute, Arrhythmia Service, Division of Cardiology, Department of Medicine, Ottawa, ON (Canada); The Ottawa Hospital, Medical Imaging Department, Ottawa, ON (Canada); University of Ottawa, Department of Radiology, Ottawa, ON (Canada)

    2016-02-15

    Cardiac sarcoidosis (CS) is a cause of conduction system disease (CSD). {sup 18}F-Fluorodeoxyglucose-positron emission tomography (FDG PET) and cardiac magnetic resonance (CMR) are used for detection of CS. The relative diagnostic value of these has not been well studied. The aim was to compare these imaging modalities in this population. We recruited steroid-naive patients with newly diagnosed CSD due to CS. All CS patients underwent both imaging studies within 12 weeks of each other. Patients were classified into two groups: group A with chronic mild CSD (right bundle branch block and/or axis deviation), and group B with new-onset atrioventricular block (AVB, Mobitz type II or third-degree AVB). Thirty patients were included. Positive findings on both imaging studies were seen in 72 % of patients (13/18) in group A and in 58 % of patients (7/12) in group B. The remainder (28 %) of the patients in group A were positive only on CMR. Of the patients in group B, 8 % were positive only on CMR and 33 % were positive only on FDG PET. Patients in group A were more likely to be positive only on CMR, and patients in group B were more likely to be positive only on FDG PET (p = 0.02). Patients in group B positive only on FDG PET underwent CMR earlier relative to their symptomatology than patients positive only on CMR (median 7.0, IQR 1.5 - 34.3, vs. 72.0, IQR 25.0 - 79.5 days; p = 0.03). The number of positive FDG PET and CMR studies was different in patients with CSD depending on their clinical presentation. This study demonstrated that CMR can adequately detect cardiac involvement associated with chronic mild CSD. In patients presenting with new-onset AVB and a negative CMR study, FDG PET may be useful for detecting cardiac involvement due to CS. (orig.)

  14. ECG-gated interventional cardiac reconstruction for non-periodic motion.

    Science.gov (United States)

    Rohkohl, Christopher; Lauritsch, Günter; Biller, Lisa; Hornegger, Joachim

    2010-01-01

    The 3-D reconstruction of cardiac vasculature using C-arm CT is an active and challenging field of research. In interventional environments patients often do have arrhythmic heart signals or cannot hold breath during the complete data acquisition. This important group of patients cannot be reconstructed with current approaches that do strongly depend on a high degree of cardiac motion periodicity for working properly. In a last year's MICCAI contribution a first algorithm was presented that is able to estimate non-periodic 4-D motion patterns. However, to some degree that algorithm still depends on periodicity, as it requires a prior image which is obtained using a simple ECG-gated reconstruction. In this work we aim to provide a solution to this problem by developing a motion compensated ECG-gating algorithm. It is built upon a 4-D time-continuous affine motion model which is capable of compactly describing highly non-periodic motion patterns. A stochastic optimization scheme is derived which minimizes the error between the measured projection data and the forward projection of the motion compensated reconstruction. For evaluation, the algorithm is applied to 5 datasets of the left coronary arteries of patients that have ignored the breath hold command and/or had arrhythmic heart signals during the data acquisition. By applying the developed algorithm the average visibility of the vessel segments could be increased by 27%. The results show that the proposed algorithm provides excellent reconstruction quality in cases where classical approaches fail. The algorithm is highly parallelizable and a clinically feasible runtime of under 4 minutes is achieved using modern graphics card hardware.

  15. Motion correction options in PET/MRI.

    Science.gov (United States)

    Catana, Ciprian

    2015-05-01

    Subject motion is unavoidable in clinical and research imaging studies. Breathing is the most important source of motion in whole-body PET and MRI studies, affecting not only thoracic organs but also those in the upper and even lower abdomen. The motion related to the pumping action of the heart is obviously relevant in high-resolution cardiac studies. These two sources of motion are periodic and predictable, at least to a first approximation, which means certain techniques can be used to control the motion (eg, by acquiring the data when the organ of interest is relatively at rest). Additionally, nonperiodic and unpredictable motion can also occur during the scan. One obvious limitation of methods relying on external devices (eg, respiratory bellows or the electrocardiogram signal to monitor the respiratory or cardiac cycle, respectively) to trigger or gate the data acquisition is that the complex motion of internal organs cannot be fully characterized. However, detailed information can be obtained using either the PET or MRI data (or both) allowing the more complete characterization of the motion field so that a motion model can be built. Such a model and the information derived from simple external devices can be used to minimize the effects of motion on the collected data. In the ideal case, all the events recorded during the PET scan would be used to generate a motion-free or corrected PET image. The detailed motion field can be used for this purpose by applying it to the PET data before, during, or after the image reconstruction. Integrating all these methods for motion control, characterization, and correction into a workflow that can be used for routine clinical studies is challenging but could potentially be extremely valuable given the improvement in image quality and reduction of motion-related image artifacts. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Extracting a respiratory signal from raw dynamic PET data that contain tracer kinetics

    International Nuclear Information System (INIS)

    Schleyer, P J; Thielemans, K; Marsden, P K

    2014-01-01

    Data driven gating (DDG) methods provide an alternative to hardware based respiratory gating for PET imaging. Several existing DDG approaches obtain a respiratory signal by observing the change in PET-counts within specific regions of acquired PET data. Currently, these methods do not allow for tracer kinetics which can interfere with the respiratory signal and introduce error. In this work, we produced a DDG method for dynamic PET studies that exhibit tracer kinetics. Our method is based on an existing approach that uses frequency-domain analysis to locate regions within raw PET data that are subject to respiratory motion. In the new approach, an optimised non-stationary short-time Fourier transform was used to create a time-varying 4D map of motion affected regions. Additional processing was required to ensure that the relationship between the sign of the respiratory signal and the physical direction of movement remained consistent for each temporal segment of the 4D map. The change in PET-counts within the 4D map during the PET acquisition was then used to generate a respiratory curve. Using 26 min dynamic cardiac NH 3 PET acquisitions which included a hardware derived respiratory measurement, we show that tracer kinetics can severely degrade the respiratory signal generated by the original DDG method. In some cases, the transition of tracer from the liver to the lungs caused the respiratory signal to invert. The new approach successfully compensated for tracer kinetics and improved the correlation between the data-driven and hardware based signals. On average, good correlation was maintained throughout the PET acquisitions. (paper)

  17. Respiratory Motion Management in PET/CT: Applications and Clinical Usefulness.

    Science.gov (United States)

    Guerra, Luca; Ponti, Elena De; Morzenti, Sabrina; Spadavecchia, Chiara; Crivellaro, Cinzia

    2017-01-01

    Breathing movement can introduce heavy bias in both image quality and quantitation in PET/CT. The aim of this paper is a review of the literature to evaluate the benefit of respiratory gating in terms of image quality, quantification and lesion detectability. A review of the literature published in the last 10 years and dealing with gated PET/CT technique has been performed, focusing on improvement in quantification, lesion detectability and diagnostic accuracy in neoplastic lesion. In addition, the improvement in the definition of radiotherapy planning has been evaluated. There is a consistent increase of the Standardized Uptake Value (SUV) in gated PET images when compared to ungated ones, particularly for lesions located in liver and in lung. Respiratory gating can also increase sensitivity, specificity and accuracy of PET/CT. Gated PET/CT can be used for radiation therapy planning, reducing the uncertainty in target definition, optimizing the volume to be treated and reducing the possibility of "missing" during the dose delivery. Moreover, new technologies, able to define the movement of lesions and organs directly from the PET sinogram, can solve some problems that currently are limiting the clinical use of gated PET/CT (i.e.: extended acquisition time, radiation exposure). The published literature demonstrated that respiratory gating PET/CT is a valid technique to improve quantification, lesion detectability of lung and liver tumors and can better define the radiotherapy planning of moving lesions and organs. If new technical improvements for motion compensation will be clinically validated, gated technique could be applied routinely in any PET/CT scan. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  18. Low-dose computed tomography scans with automatic exposure control for patients of different ages undergoing cardiac PET/CT and SPECT/CT.

    Science.gov (United States)

    Yang, Ching-Ching; Yang, Bang-Hung; Tu, Chun-Yuan; Wu, Tung-Hsin; Liu, Shu-Hsin

    2017-06-01

    This study aimed to evaluate the efficacy of automatic exposure control (AEC) in order to optimize low-dose computed tomography (CT) protocols for patients of different ages undergoing cardiac PET/CT and single-photon emission computed tomography/computed tomography (SPECT/CT). One PET/CT and one SPECT/CT were used to acquire CT images for four anthropomorphic phantoms representative of 1-year-old, 5-year-old and 10-year-old children and an adult. For the hybrid systems investigated in this study, the radiation dose and image quality of cardiac CT scans performed with AEC activated depend mainly on the selection of a predefined image quality index. Multiple linear regression methods were used to analyse image data from anthropomorphic phantom studies to investigate the effects of body size and predefined image quality index on CT radiation dose in cardiac PET/CT and SPECT/CT scans. The regression relationships have a coefficient of determination larger than 0.9, indicating a good fit to the data. According to the regression models, low-dose protocols using the AEC technique were optimized for patients of different ages. In comparison with the standard protocol with AEC activated for adult cardiac examinations used in our clinical routine practice, the optimized paediatric protocols in PET/CT allow 32.2, 63.7 and 79.2% CT dose reductions for anthropomorphic phantoms simulating 10-year-old, 5-year-old and 1-year-old children, respectively. The corresponding results for cardiac SPECT/CT are 8.4, 51.5 and 72.7%. AEC is a practical way to reduce CT radiation dose in cardiac PET/CT and SPECT/CT, but the AEC settings should be determined properly for optimal effect. Our results show that AEC does not eliminate the need for paediatric protocols and CT examinations using the AEC technique should be optimized for paediatric patients to reduce the radiation dose as low as reasonably achievable.

  19. A gate evaluation of the sources of error in quantitative90 Y PET.

    Science.gov (United States)

    Strydhorst, Jared; Carlier, Thomas; Dieudonné, Arnaud; Conti, Maurizio; Buvat, Irène

    2016-10-01

    Accurate reconstruction of the dose delivered by 90 Y microspheres using a postembolization PET scan would permit the establishment of more accurate dose-response relationships for treatment of hepatocellular carcinoma with 90 Y. However, the quality of the PET data obtained is compromised by several factors, including poor count statistics and a very high random fraction. This work uses Monte Carlo simulations to investigate what impact factors other than low count statistics have on the quantification of 90 Y PET. PET acquisitions of two phantoms-a NEMA PET phantom and the NEMA IEC PET body phantom-containing either 90 Y or 18 F were simulated using gate. Simulated projections were created with subsets of the simulation data allowing the contributions of random, scatter, and LSO background to be independently evaluated. The simulated projections were reconstructed using the commercial software for the simulated scanner, and the quantitative accuracy of the reconstruction and the contrast recovery of the reconstructed images were evaluated. The quantitative accuracy of the 90 Y reconstructions were not strongly influenced by the high random fraction present in the projection data, and the activity concentration was recovered to within 5% of the known value. The contrast recovery measured for simulated 90 Y data was slightly poorer than that for simulated 18 F data with similar count statistics. However, the degradation was not strongly linked to any particular factor. Using a more restricted energy range to reduce the random fraction in the projections had no significant effect. Simulations of 90 Y PET confirm that quantitative 90 Y is achievable with the same approach as that used for 18 F, and that there is likely very little margin for improvement by attempting to model aspects unique to 90 Y, such as the much higher random fraction or the presence of bremsstrahlung in the singles data. © 2016 American Association of Physicists in Medicine.

  20. Clinical impact of 18F-FDG-PET/CT in the extra cardiac work-up of patients with infective endocarditis

    DEFF Research Database (Denmark)

    Asmar, Ali; Ozcan, Cengiz; Diederichsen, Axel C P

    2014-01-01

    OBJECTIVE: The purpose of this study was to assess the clinical importance of (18)F-FDG-PET/CT used in the extra cardiac work-up of patients with infective endocarditis (IE). BACKGROUND: IE is a serious condition with a significant mortality. Besides the degree of valvular involvement, the progno......OBJECTIVE: The purpose of this study was to assess the clinical importance of (18)F-FDG-PET/CT used in the extra cardiac work-up of patients with infective endocarditis (IE). BACKGROUND: IE is a serious condition with a significant mortality. Besides the degree of valvular involvement...

  1. Coronary endothelial function assessment using self-gated cardiac cine MRI and k-t sparse SENSE.

    Science.gov (United States)

    Yerly, Jérôme; Ginami, Giulia; Nordio, Giovanna; Coristine, Andrew J; Coppo, Simone; Monney, Pierre; Stuber, Matthias

    2016-11-01

    Electrocardiogram (ECG)-gated cine MRI, paired with isometric handgrip exercise, can be used to accurately, reproducibly, and noninvasively measure coronary endothelial function (CEF). Obtaining a reliable ECG signal at higher field strengths, however, can be challenging due to rapid gradient switching and an increased heart rate under stress. To address these limitations, we present a self-gated cardiac cine MRI framework for CEF measurements that operates without ECG signal. Cross-sectional slices of the right coronary artery (RCA) were acquired using a two-dimensional golden angle radial trajectory. This sampling approach, combined with the k-t sparse SENSE algorithm, allows for the reconstruction of both real-time images for self-gating signal calculations and retrospectively reordered self-gated cine images. CEF measurements were quantitatively compared using both the self-gated and the standard ECG-gated approach. Self-gated cine images with high-quality, temporal, and spatial resolution were reconstructed for 18 healthy volunteers. CEF as measured in self-gated images was in good agreement (R 2  = 0.60) with that measured by its standard ECG-gated counterpart. High spatial and temporal resolution cross-sectional cine images of the RCA can be obtained without ECG signal. The coronary vasomotor response to handgrip exercise compares favorably with that obtained with the standard ECG-gated method. Magn Reson Med 76:1443-1454, 2015. © 2015 International Society for Magnetic Resonance in Medicine. © 2015 International Society for Magnetic Resonance in Medicine.

  2. 3-D cardiac MRI in free-breathing newborns and infants: when is respiratory gating necessary?

    Energy Technology Data Exchange (ETDEWEB)

    Seeger, Achim [University Hospital of Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany); University Hospital of Tuebingen, Department of Diagnostic and Interventional Neuroradiology, Tuebingen (Germany); Krumm, Patrick; Schaefer, Juergen F.; Kramer, Ulrich [University Hospital of Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany); Hornung, Andreas; Sieverding, Ludger [University Hospital of Tuebingen, Department of Pediatric Cardiology, Tuebingen (Germany)

    2015-09-15

    Newborns and small infants have shallow breathing. To suggest criteria for when respiratory gating is necessary during cardiac MRI in newborns and infants. One-hundred ten data sets of newborns and infants with (n = 92, mean age: 1.9 ± 1.7 [SD] years) and without (n = 18, mean age: 1.6 ± 1.8 [SD] years) navigator gating were analysed retrospectively. The respiratory motion of the right hemidiaphragm was recorded and correlated to age, weight, body surface area and qualitative image quality on a 4-point score. Quantitative image quality assessment was performed (sharpness of the delineation of the ventricular septal wall) as well as a matched-pair comparison between navigator-gated and non-gated data sets. No significant differences were found in overall image quality or in the sharpness of the ventricular septal wall between gated and non-gated scans. A navigator acceptance of >80% was frequently found in patients ages <12 months, body surface area <0.40 m{sup 2}, body weight <10 kg and a size of <80 cm. Sequences without respiratory gating may be used in newborns and small infants, in particular if age <12 months, body surface area <0.40 m{sup 2}, body weight <10 kg and height <80 cm. (orig.)

  3. Estimation of the displacement of cardiac substructures and the motion of the coronary arteries using electrocardiographic gating

    Directory of Open Access Journals (Sweden)

    Tan W

    2013-09-01

    Full Text Available Wenyong Tan,1,* Liying Xu,2,* Xiaohong Wang,1 Dasheng Qiu,3 Guang Han,1 Desheng Hu1 1Department of Radiation Oncology, Hubei Cancer Hospital, Wuhan, People’s Republic of China; 2Department of Radiology, Zhongnan Hospital, Wuhan University, Wuhan, People’s Republic of China; 3PET-CT Center, Hubei Cancer Hospital, Wuhan, People’s Republic of China *These authors have contributed equally to this paper Purpose: The aim of this study was to quantify the displacement of cardiac substructures, including the anterior myocardial territory (AMT, left ventricle, and coronary arteries during a normal cardiac cycle. Materials and methods: Computed tomography (CT images with retrospective electrocardiographic gating of 17 eligible patients were obtained. All images were reconstructed automatically for the end-diastolic and end-systolic phases. CT scanning without contrast at a random phase and a selected vertebral body were used as references to measure three-dimensionaldisplacements of the cardiac substructures. Results: The displacement between the end-diastolic and end-systolic phases (Dd-s was greater than that between the end-systolic and random phases and between the end-diastolic and random cardiac phases. The largest displacements for the heart were in the left, posterior, and inferior directions with an average Dd-s of approximately 4–6 mm. The average Dd-s for the AMT and left ventricle was 1.2–2.7 mm in the anterior and right directions, 4.3–7.8 mm in left and posterior directions, and 4.9–6.3 mm in superior and inferior directions. For the coronary arteries, the average Dd-s was 2.8–5.9 mm in the anterior-posterior direction, 3.5–6.6 mm in left-right direction, and 3.8–5.3 mm in the superior-inferior direction. Inter-observer agreement was excellent for the heart, AMT, and left ventricle (kappa coefficient, >0.75 for all and good for most coronary arteries in three dimensions (kappa coefficient, 0.511–0.687. The Dd-s did not

  4. Residual motion compensation in ECG-gated interventional cardiac vasculature reconstruction

    Science.gov (United States)

    Schwemmer, C.; Rohkohl, C.; Lauritsch, G.; Müller, K.; Hornegger, J.

    2013-06-01

    Three-dimensional reconstruction of cardiac vasculature from angiographic C-arm CT (rotational angiography) data is a major challenge. Motion artefacts corrupt image quality, reducing usability for diagnosis and guidance. Many state-of-the-art approaches depend on retrospective ECG-gating of projection data for image reconstruction. A trade-off has to be made regarding the size of the ECG-gating window. A large temporal window is desirable to avoid undersampling. However, residual motion will occur in a large window, causing motion artefacts. We present an algorithm to correct for residual motion. Our approach is based on a deformable 2D-2D registration between the forward projection of an initial, ECG-gated reconstruction, and the original projection data. The approach is fully automatic and does not require any complex segmentation of vasculature, or landmarks. The estimated motion is compensated for during the backprojection step of a subsequent reconstruction. We evaluated the method using the publicly available CAVAREV platform and on six human clinical datasets. We found a better visibility of structure, reduced motion artefacts, and increased sharpness of the vessels in the compensated reconstructions compared to the initial reconstructions. At the time of writing, our algorithm outperforms the leading result of the CAVAREV ranking list. For the clinical datasets, we found an average reduction of motion artefacts by 13 ± 6%. Vessel sharpness was improved by 25 ± 12% on average.

  5. Validation of cardiac {sup 123}I-MIBG scintigraphy in patients with Parkinson's disease who were diagnosed with dopamine PET

    Energy Technology Data Exchange (ETDEWEB)

    Ishibashi, Kenji [Tokyo Medical and Dental University, Department of Neurology and Neurological Science, Graduate School, Tokyo (Japan); Tokyo Metropolitan Institute of Gerontology, Positron Medical Center, Tokyo (Japan); Saito, Yuko [Tokyo Metropolitan Geriatric Hospital, Department of Pathology, Tokyo (Japan); Tokyo Metropolitan Institute of Gerontology, Department of Neuropathology, Tokyo (Japan); Murayama, Shigeo [Tokyo Metropolitan Institute of Gerontology, Department of Neuropathology, Tokyo (Japan); Kanemaru, Kazutomi [Tokyo Metropolitan Geriatric Hospital, Department of Neurology, Tokyo (Japan); Oda, Keiichi; Ishiwata, Kiichi; Ishii, Kenji [Tokyo Metropolitan Institute of Gerontology, Positron Medical Center, Tokyo (Japan); Mizusawa, Hidehiro [Tokyo Medical and Dental University, Department of Neurology and Neurological Science, Graduate School, Tokyo (Japan)

    2010-01-15

    The aim of this study was to evaluate the diagnostic potential of cardiac {sup 123}I-labelled metaiodobenzylguanidine ({sup 123}I-MIBG) scintigraphy in idiopathic Parkinson's disease (PD). The diagnosis was confirmed by positron emission tomography (PET) imaging with {sup 11}C-labelled 2{beta}-carbomethoxy-3{beta}-(4-fluorophenyl)-tropane ({sup 11}C-CFT) and {sup 11}C-raclopride (together designated as dopamine PET). Cardiac {sup 123}I-MIBG scintigraphy and dopamine PET were performed for 39 parkinsonian patients. To estimate the cardiac {sup 123}I-MIBG uptake, heart to mediastinum (H/M) ratios in early and delayed images were calculated. On the basis of established clinical criteria and our dopamine PET findings, 24 patients were classified into the PD group and 15 into the non-PD (NPD) group. Both early and delayed images showed that the H/M ratios were significantly lower in the PD group than in the NPD group. When the optimal cut-off levels of the H/M ratio were set at 1.95 and 1.60 in the early and delayed images, respectively, by receiver-operating characteristic analysis, the sensitivity of cardiac {sup 123}I-MIBG scintigraphy for the diagnosis of PD was 79.2 and 70.8% and the specificity was 93.3 and 93.3% in the early and delayed images, respectively. In the Hoehn and Yahr 1 and 2 PD patients, the sensitivity decreased by 69.2 and 53.8% in the early and delayed images, respectively. In early PD cases, cardiac {sup 123}I-MIBG scintigraphy is of limited value in the diagnosis, because of its relatively lower sensitivity. However, because of its high specificity for the overall cases, cardiac {sup 123}I-MIBG scintigraphy may assist in the diagnosis of PD in a complementary role with the dopaminergic neuroimaging. (orig.)

  6. Comparative evaluation of CT-based and respiratory-gated PET/CT-based planning target volume (PTV) in the definition of radiation treatment planning in lung cancer: preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Guerra, Luca; Elisei, Federica [San Gerardo Hospital, Nuclear Medicine, Monza (Italy); Meregalli, Sofia; Niespolo, Rita [San Gerardo Hospital, Radiotherapy, Monza (Italy); Zorz, Alessandra; De Ponti, Elena; Morzenti, Sabrina; Crespi, Andrea [San Gerardo Hospital, Medical Physics, Monza (Italy); Brenna, Sarah [University of Milan-Bicocca, School of Radiation Oncology, Monza (Italy); Gardani, Gianstefano [San Gerardo Hospital, Radiotherapy, Monza (Italy); University of Milan-Bicocca, Milan (Italy); Messa, Cristina [San Gerardo Hospital, Nuclear Medicine, Monza (Italy); University of Milan-Bicocca, Tecnomed Foundation, Milan (Italy); National Research Council, Institute for Bioimaging and Molecular Physiology, Milan (Italy)

    2014-04-15

    The aim of this study was to compare planning target volume (PTV) defined on respiratory-gated positron emission tomography (PET)/CT (RG-PET/CT) to PTV based on ungated free-breathing CT and to evaluate if RG-PET/CT can be useful to personalize PTV by tailoring the target volume to the lesion motion in lung cancer patients. Thirteen lung cancer patients (six men, mean age 70.0 years, 1 small cell lung cancer, 12 non-small cell lung cancer) who were candidates for radiation therapy were prospectively enrolled and submitted to RG-PET/CT. Ungated free-breathing CT images obtained during a PET/CT study were visually contoured by the radiation oncologist to define standard clinical target volumes (CTV1). Standard PTV (PTV1) resulted from CTV1 with the addition of 1-cm expansion of margins in all directions. RG-PET/CT images were contoured by the nuclear medicine physician and radiation oncologist according to a standardized institutional protocol for contouring gated images. Each CT and PET image of the patient's respiratory cycle phases was contoured to obtain the RG-CT-based CTV (CTV2) and the RG-PET/CT-based CTV (CTV3), respectively. RG-CT-based and RG-PET/CT-based PTV (PTV2 and PTV3, respectively) were then derived from gated CTVs with a margin expansion of 7-8 mm in head to feet direction and 5 mm in anterior to posterior and left to right direction. The portions of gated PTV2 and PTV3 geometrically not encompassed in PTV1 (PTV2 out PTV1 and PTV3 out PTV1) were also calculated. Mean ± SD CTV1, CTV2 and CTV3 were 30.5 ± 33.2, 43.1 ± 43.2 and 44.8 ± 45.2 ml, respectively. CTV1 was significantly smaller than CTV2 and CTV3 (p = 0.017 and 0.009 with Student's t test, respectively). No significant difference was found between CTV2 and CTV3. Mean ± SD of PTV1, PTV2 and PTV3 were 118.7 ± 94.1, 93.8 ± 80.2 and 97.0 ± 83.9 ml, respectively. PTV1 was significantly larger than PTV2 and PTV3 (p = 0.038 and 0.043 with Student's t test, respectively). No

  7. PET and SPET tracers for mapping the cardiac nervous system

    International Nuclear Information System (INIS)

    Langer, Oliver; Halldin, Christer

    2002-01-01

    The human cardiac nervous system consists of a sympathetic and a parasympathetic branch with (-)-norepinephrine and acetylcholine as the respective endogenous neurotransmitters. Dysfunction of the cardiac nervous system is implicated in various types of cardiac disease, such as heart failure, myocardial infarction and diabetic autonomic neuropathy. In vivo assessment of the distribution and function of cardiac sympathetic and parasympathetic neurones with positron emission tomography (PET) and single-photon emission tomography (SPET) can be achieved by means of a number of carbon-11-, fluorine-18-, bromine-76- and iodine-123-labelled tracer molecules. Available tracers for mapping sympathetic neurones can be divided into radiolabelled catecholamines, such as 6-[ 18 F]fluorodopamine, (-)-6-[ 18 F]fluoronorepinephrine and (-)-[ 11 C]epinephrine, and radiolabelled catecholamine analogues, such as [ 123 I]meta-iodobenzylguanidine, [ 11 C]meta-hydroxyephedrine, [ 18 F]fluorometaraminol, [ 11 C]phenylephrine and meta-[ 76 Br]bromobenzylguanidine. Resistance to metabolism by monoamine oxidase and catechol-O-methyl transferase simplifies the myocardial kinetics of the second group. Both groups of compounds are excellent agents for an overall assessment of sympathetic innervation. Biomathematical modelling of tracer kinetics is complicated by the complexity of the steps governing neuronal uptake, retention and release of these agents as well as by their high neuronal affinity, which leads to partial flow dependence of uptake. Mapping of cardiac parasympathetic neurones is limited by a low density and focal distribution pattern of these neurones in myocardium. Available tracers are derivatives of vesamicol, a molecule that binds to a receptor associated with the vesicular acetylcholine transporter. Compounds like (-)-[ 18 F]fluoroethoxybenzovesamicol display a high degree of non-specific binding in myocardium which restricts their utility for cardiac neuronal imaging. (orig.)

  8. GATE V6: a major enhancement of the GATE simulation platform enabling modelling of CT and radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Jan, S; Becheva, E [DSV/I2BM/SHFJ, Commissariat a l' Energie Atomique, Orsay (France); Benoit, D; Rehfeld, N; Stute, S; Buvat, I [IMNC-UMR 8165 CNRS-Paris 7 and Paris 11 Universities, 15 rue Georges Clemenceau, 91406 Orsay Cedex (France); Carlier, T [INSERM U892-Cancer Research Center, University of Nantes, Nantes (France); Cassol, F; Morel, C [Centre de physique des particules de Marseille, CNRS-IN2P3 and Universite de la Mediterranee, Aix-Marseille II, 163, avenue de Luminy, 13288 Marseille Cedex 09 (France); Descourt, P; Visvikis, D [INSERM, U650, Laboratoire du Traitement de l' Information Medicale (LaTIM), CHU Morvan, Brest (France); Frisson, T; Grevillot, L; Guigues, L; Sarrut, D; Zahra, N [Universite de Lyon, CREATIS, CNRS UMR5220, Inserm U630, INSA-Lyon, Universite Lyon 1, Centre Leon Berard (France); Maigne, L; Perrot, Y [Laboratoire de Physique Corpusculaire, 24 Avenue des Landais, 63177 Aubiere Cedex (France); Schaart, D R [Delft University of Technology, Radiation Detection and Medical Imaging, Mekelweg 15, 2629 JB Delft (Netherlands); Pietrzyk, U, E-mail: buvat@imnc.in2p3.fr [Reseach Center Juelich, Institute of Neurosciences and Medicine and Department of Physics, University of Wuppertal (Germany)

    2011-02-21

    GATE (Geant4 Application for Emission Tomography) is a Monte Carlo simulation platform developed by the OpenGATE collaboration since 2001 and first publicly released in 2004. Dedicated to the modelling of planar scintigraphy, single photon emission computed tomography (SPECT) and positron emission tomography (PET) acquisitions, this platform is widely used to assist PET and SPECT research. A recent extension of this platform, released by the OpenGATE collaboration as GATE V6, now also enables modelling of x-ray computed tomography and radiation therapy experiments. This paper presents an overview of the main additions and improvements implemented in GATE since the publication of the initial GATE paper (Jan et al 2004 Phys. Med. Biol. 49 4543-61). This includes new models available in GATE to simulate optical and hadronic processes, novelties in modelling tracer, organ or detector motion, new options for speeding up GATE simulations, examples illustrating the use of GATE V6 in radiotherapy applications and CT simulations, and preliminary results regarding the validation of GATE V6 for radiation therapy applications. Upon completion of extensive validation studies, GATE is expected to become a valuable tool for simulations involving both radiotherapy and imaging.

  9. Added diagnostic value of respiratory-gated 4D 18F-FDG PET/CT in the detection of liver lesions. A multicenter study

    Energy Technology Data Exchange (ETDEWEB)

    Crivellaro, Cinzia; Landoni, Claudio; Guerra, Luca [San Gerardo Hospital, Nuclear Medicine, Monza (Italy); University of Milan-Bicocca, Milan (Italy); De Ponti, Elena; Morzenti, Sabrina [San Gerardo Hospital, Medical Physics, Monza (Italy); Elisei, Federica [San Gerardo Hospital, Nuclear Medicine, Monza (Italy); Picchio, Maria; Bettinardi, Valentino [IRCCS San Raffaele Scientific Institute, Nuclear Medicine, Milan (Italy); Versari, Annibale [Santa Maria Nuova Hospital IRCCS, Nuclear Medicine, Reggio Emilia (Italy); Fioroni, Federica [Santa Maria Nuova Hospital IRCCS, Medical Physics, Reggio Emilia (Italy); Dziuk, Miroslaw; Tkaczewski, Konrad [Military Institute of Medicine, Warsaw (Poland); Ahond-Vionnet, Renee; Nodari, Guillaume [Hopital Pierre Beregovoy, Service de Medecine Nucleaire, Nevers (France); Todde, Sergio [University of Milan-Bicocca, Tecnomed Foundation, Monza (Italy)

    2018-01-15

    The aim of the present study was to evaluate the added diagnostic value of respiratory-gated 4D18F-FDG PET/CT in liver lesion detection and characterization in a European multicenter retrospective study. Fifty-six oncological patients (29 males and 27 females, mean age, 61.2 ± 11.2 years) from five European centers, submitted to standard 3D-PET/CT and liver 4D-PET/CT were retrospectively evaluated. Based on visual analysis, liver PET/CT findings were scored as positive, negative, or equivocal both in 3D and 4D PET/CT. The impact of 4D-PET/CT on the confidence in classifying liver lesions was assessed. PET/CT findings were compared to histology and clinical follow-up as standard reference and diagnostic accuracy was calculated for both techniques. At semi-quantitative analysis, SUVmax was calculated for each detected lesion in 3D and 4D-PET/CT. Overall, 72 liver lesions were considered for the analysis. Based on visual analysis in 3D-PET/CT, 32/72 (44.4%) lesions were considered positive, 21/72 (29.2%) negative, and 19/72 (26.4%) equivocal, while in 4D-PET/CT 48/72 (66.7%) lesions were defined positive, 23/72 (31.9%) negative, and 1/72 (1.4%) equivocal. 4D-PET/CT findings increased the confidence in lesion definition in 37/72 lesions (51.4%). Considering 3D equivocal lesions as positive, sensitivity, specificity, and accuracy were 88.9, 70.0, and 83.1%, respectively, while the same figures were 67.7, 90.0, and 73.8% if 3D equivocal findings were included as negative. 4D-PET/CT sensitivity, specificity, and accuracy were 97.8, 90.0, and 95.4%, respectively, considering equivocal lesions as positive and 95.6, 90.0, and 93.8% considering equivocal lesions as negative. The SUVmax of the liver lesions in 4D-PET (mean ± SD, 6.9 ± 3.2) was significantly higher (p < 0.001) than SUVmax in 3D-PET (mean ± SD, 5.2 ± 2.3). Respiratory-gated PET/CT technique is a valuable clinical tool in diagnosing liver lesions, reducing 3D undetermined findings, improving diagnostic

  10. Residual motion compensation in ECG-gated interventional cardiac vasculature reconstruction

    International Nuclear Information System (INIS)

    Schwemmer, C; Müller, K; Hornegger, J; Rohkohl, C; Lauritsch, G

    2013-01-01

    Three-dimensional reconstruction of cardiac vasculature from angiographic C-arm CT (rotational angiography) data is a major challenge. Motion artefacts corrupt image quality, reducing usability for diagnosis and guidance. Many state-of-the-art approaches depend on retrospective ECG-gating of projection data for image reconstruction. A trade-off has to be made regarding the size of the ECG-gating window. A large temporal window is desirable to avoid undersampling. However, residual motion will occur in a large window, causing motion artefacts. We present an algorithm to correct for residual motion. Our approach is based on a deformable 2D–2D registration between the forward projection of an initial, ECG-gated reconstruction, and the original projection data. The approach is fully automatic and does not require any complex segmentation of vasculature, or landmarks. The estimated motion is compensated for during the backprojection step of a subsequent reconstruction. We evaluated the method using the publicly available CAVAREV platform and on six human clinical datasets. We found a better visibility of structure, reduced motion artefacts, and increased sharpness of the vessels in the compensated reconstructions compared to the initial reconstructions. At the time of writing, our algorithm outperforms the leading result of the CAVAREV ranking list. For the clinical datasets, we found an average reduction of motion artefacts by 13 ± 6%. Vessel sharpness was improved by 25 ± 12% on average. (paper)

  11. A GATE evaluation of the sources of error in quantitative {sup 90}Y PET

    Energy Technology Data Exchange (ETDEWEB)

    Strydhorst, Jared, E-mail: jared.strydhorst@gmail.com; Buvat, Irène [IMIV, U1023 Inserm/CEA/Université Paris-Sud and ERL 9218 CNRS, Université Paris-Saclay, CEA/SHFJ, Orsay 91401 (France); Carlier, Thomas [Department of Nuclear Medicine, Centre Hospitalier Universitaire de Nantes and CRCNA, Inserm U892, Nantes 44000 (France); Dieudonné, Arnaud [Department of Nuclear Medicine, Hôpital Beaujon, HUPNVS, APHP and Inserm U1149, Clichy 92110 (France); Conti, Maurizio [Siemens Healthcare Molecular Imaging, Knoxville, Tennessee, 37932 (United States)

    2016-10-15

    Purpose: Accurate reconstruction of the dose delivered by {sup 90}Y microspheres using a postembolization PET scan would permit the establishment of more accurate dose–response relationships for treatment of hepatocellular carcinoma with {sup 90}Y. However, the quality of the PET data obtained is compromised by several factors, including poor count statistics and a very high random fraction. This work uses Monte Carlo simulations to investigate what impact factors other than low count statistics have on the quantification of {sup 90}Y PET. Methods: PET acquisitions of two phantoms—a NEMA PET phantom and the NEMA IEC PET body phantom-containing either {sup 90}Y or {sup 18}F were simulated using GATE. Simulated projections were created with subsets of the simulation data allowing the contributions of random, scatter, and LSO background to be independently evaluated. The simulated projections were reconstructed using the commercial software for the simulated scanner, and the quantitative accuracy of the reconstruction and the contrast recovery of the reconstructed images were evaluated. Results: The quantitative accuracy of the {sup 90}Y reconstructions were not strongly influenced by the high random fraction present in the projection data, and the activity concentration was recovered to within 5% of the known value. The contrast recovery measured for simulated {sup 90}Y data was slightly poorer than that for simulated {sup 18}F data with similar count statistics. However, the degradation was not strongly linked to any particular factor. Using a more restricted energy range to reduce the random fraction in the projections had no significant effect. Conclusions: Simulations of {sup 90}Y PET confirm that quantitative {sup 90}Y is achievable with the same approach as that used for {sup 18}F, and that there is likely very little margin for improvement by attempting to model aspects unique to {sup 90}Y, such as the much higher random fraction or the presence of

  12. Respiratory gated PET/CT in a European multicentre retrospective study: added diagnostic value in detection and characterization of lung lesions

    Energy Technology Data Exchange (ETDEWEB)

    Guerra, Luca; Elisei, Federica [San Gerardo Hospital, Nuclear Medicine, Monza (Italy); De Ponti, Elena [San Gerardo Hospital, Medical Physics, Monza (Italy); Bettinardi, Valentino; Picchio, Maria [San Raffaele Scientific Institute, Nuclear Medicine, Milan (Italy); National Research Council, Institute for Bioimaging and Molecular Physiology, Milan (Italy); Landoni, Claudio [San Raffaele Scientific Institute, Nuclear Medicine, Milan (Italy); University of Milano-Bicocca, Milan (Italy); Gilardi, Maria Carla [San Raffaele Scientific Institute, Nuclear Medicine, Milan (Italy); National Research Council, Institute for Bioimaging and Molecular Physiology, Milan (Italy); University of Milano-Bicocca, Tecnomed Foundation, Milan (Italy); Versari, Annibale [Scientific Institute Santa Maria Nuova Hospital, Nuclear Medicine, Reggio Emilia (Italy); Fioroni, Federica [Scientific Institute Santa Maria Nuova Hospital, Medical Physics, Reggio Emilia (Italy); Dziuk, Miroslaw [Masovian PET-CT Centre, Department of Nuclear Medicine, Military Institute of Medicine, Warsaw (Poland); Koza, Magdalena [Masovian PET-CT Centre, Euromedic Diagnostic, Warsaw (Poland); Ahond-Vionnet, Renee; Collin, Bertrand [Hopital Pierre Beregovoy, Service de Medecine Nucleaire, Nevers (France); Messa, Cristina [San Gerardo Hospital, Nuclear Medicine, Monza (Italy); National Research Council, Institute for Bioimaging and Molecular Physiology, Milan (Italy); University of Milano-Bicocca, Tecnomed Foundation, Milan (Italy)

    2012-09-15

    The aim of our work is to evaluate the added diagnostic value of respiratory gated (4-D) positron emission tomography/computed tomography (PET/CT) in lung lesion detection/characterization in a large patient population of a multicentre retrospective study. The data of 155 patients (89 men, 66 women, mean age 63.9 {+-} 11.1 years) from 5 European centres and submitted to standard (3-D) and 4-D PET/CT were retrospectively analysed. Overall, 206 lung lesions were considered for the analysis (mean {+-} SD lesions dimension 14.7 {+-} 11.8 mm). Maximum standardized uptake values (SUV{sub max}) and lesion detectability were assessed for both 3-D and 4-D PET/CT studies; 3-D and 4-D PET/CT findings were compared to clinical follow-up as standard reference. Mean {+-} SD 3-D and 4-D SUV{sub max} values were 5.2 {+-} 5.1 and 6.8 {+-} 6.1 (p < 0.0001), respectively, with an average percentage increase of 30.8 %. In 3-D PET/CT, 86 of 206 (41.7 %) lesions were considered positive, 70 of 206 (34 %) negative and 50 of 206 (24.3 %) equivocal, while in 4-D PET/CT 117 of 206 (56.8 %) lesions were defined as positive, 80 of 206 (38.8 %) negative and 9 of 206 (4.4 %) equivocal. In 34 of 50 (68 %) 3-D equivocal lesions follow-up data were available and the presence of malignancy was confirmed in 21 of 34 (61.8 %) lesions, while in 13 of 34 (38.2 %) was excluded. In 31 of these 34 controlled lesions, 20 of 34 (58.8 %) and 11 of 34 (32.4 %) were correctly classified by 4-D PET/CT as positive and negative, respectively; 3 of 34 (8.8 %) remained equivocal. With equivocal lesions classified as positive, the overall accuracy of 3-D and 4-D was 85.7 and 92.8 %, respectively, while the same figures were 80.5 and 94.2 % when equivocal lesions were classified as negative. The respiratory gated PET/CT technique is a valuable clinical tool in diagnosing lung lesions, improving quantification and confidence in reporting, reducing 3-D undetermined findings and increasing the overall accuracy in lung

  13. Cardiac failure due to arteriovenous fistula with brachiocephalic stenosis: a gated heart case study

    International Nuclear Information System (INIS)

    Abel, G.; Irish, A.; Henderson, A.; Lenzo, N.

    2003-01-01

    Full text: There are numerous causes of cardiac failure of which the commonest in our community include ischaemic cardiomyopathy, post-viral cardiomyopathy, alcohol-induced cardiomyopathy and drug-induced cardiomyopathy. All these entities cause low output cardiac failure however high output cardiac failure is also well recognised. This includes heart failure related to such conditions as hyperthyroidism, anaemia, pregnancy, beri-beri, and Paget's disease. A rare cause of high output cardiac failure is an arteriovenous fistula. We present an unusual case of a patient with end-stage renal failure on haemodialysis who developed extensive dilatation of their left arm arteriovenous fistula secondary to bachiocephalic vein stenosis. The labelled red blood cell gated heart blood pool study demonstrated decreased left ventricular function and extensive pooling of blood within the tortuous dilated left arm vessels. A follow-up study post-ligation of the arteriovenous fistula showed improvement of the left ventricular ejection fraction. The associated contrast venography findings are also demonstrated. Copyright (2003) The Australian and New Zealand Society of Nuclear Medicine Inc

  14. Contrast-enhanced specific absorption rate-efficient 3D cardiac cine with respiratory-triggered radiofrequency gating.

    Science.gov (United States)

    Henningsson, Markus; Chan, Raymond H; Goddu, Beth; Goepfert, Lois A; Razavi, Reza; Botnar, Rene M; Schaeffter, Tobias; Nezafat, Reza

    2013-04-01

    To investigate the use of radiofrequency (RF) gating in conjunction with a paramagnetic contrast agent to reduce the specific absorption rate (SAR) and increase the blood-myocardium contrast in balanced steady-state free precession (bSSFP) 3D cardiac cine. RF gating was implemented by synchronizing the RF-excitation with an external respiratory sensor (bellows), which could additionally be used for respiratory gating. For reference, respiratory-gated 3D cine images were acquired without RF gating. Free-breathing 3D cine images were acquired in eight healthy subjects before and after contrast injection (Gd-BOPTA) and compared to breath-hold 2D cine. RF-gated 3D cine reduced the SAR by nearly 40% without introducing significant artifacts while providing left ventricle (LV) measurements similar to those obtained with 2D cine. The contrast-to-noise ratio (CNR) was significantly higher for 3D cine compared to 2D cine, both before and after contrast injection; however, no statistically significant CNR increase was observed for the postcontrast 3D cine compared to the precontrast acquisitions. Respiratory-triggered RF gating significantly reduces SAR in 3D cine acquisitions, which may enable a more widespread clinical use of 3D cine. Furthermore, CNR of 3D bSSFP cine is higher than of 2D and administration of Gd-BOPTA does not improve the CNR of 3D cine. Copyright © 2012 Wiley Periodicals, Inc.

  15. Evaluation of regional wall motion in myocardial infarction using animation ECG gated cardiac computed tomography

    International Nuclear Information System (INIS)

    Shimizu, Takahiko; Hyodo, Haruo; Hayashi, Terumi; Yamamoto, Hideo; Yagi, Shigeru

    1984-01-01

    Regional wall motion of the left ventricle was evaluated in 21 patients with myocardial infarction using an animation system of gated cardiac computed tomographic (CT) images (animation gated CCT). The results obtained were compared with data by two-dimensional echocardiography (2-DE). 1. Evaluation of the asynergic area by animation gated CCT and 2-DE: Animation gated CCT detected the following specific regions with asynergy established by 2-DE; 10/10 cases (100%) at the anterior wall of the left ventricle, 14/14 cases (100%) at the interventricular septum, and 9/11 cases (81.8%) at the infero-posterior wall. In addition, one false positive case and one negative case were observed at the lateral wall and the apex, respectively. Of 37 instances with asynergic areas established by 2-DE, 21 cases or 89.2% were detected by animation gated CCT; the sensitivity was 91.9%. 2. Evaluation of severity of asynergy by animation gated CCT and 2-DE: The degree of asynergy evaluated by both methods was compared with each other, and the agreement was as follows: 10/10 cases (100%) at the left-ventricular anterior wall, 13/13 cases (100%) at the interventricular septum, and 7/9 cases (77.8%) at the infero-posterior wall. 3. Evaluation of the asynergic area by nonanimation gated CCT and 2-DE: Nonanimation gated CCT detected asynergic areas ascertained by 2-DE at the following areas; 8/10 cases (80%) at the left-ventricular anterior wall, 12/14 cases (85.7%) at the interventricular septum, and 4/11 cases (36.4%) at the infero-posterior wall. The difference between animation and nonanimation gated CCT was statistically significant (p<0.05). The severity of asynergy could not be evaluated by nonanimation gated CCT. (J.P.N.)

  16. Registration and Summation of Respiratory-Gated or Breath-Hold PET Images Based on Deformation Estimation of Lung from CT Image

    Directory of Open Access Journals (Sweden)

    Hideaki Haneishi

    2016-01-01

    Full Text Available Lung motion due to respiration causes image degradation in medical imaging, especially in nuclear medicine which requires long acquisition times. We have developed a method for image correction between the respiratory-gated (RG PET images in different respiration phases or breath-hold (BH PET images in an inconsistent respiration phase. In the method, the RG or BH-PET images in different respiration phases are deformed under two criteria: similarity of the image intensity distribution and smoothness of the estimated motion vector field (MVF. However, only these criteria may cause unnatural motion estimation of lung. In this paper, assuming the use of a PET-CT scanner, we add another criterion that is the similarity for the motion direction estimated from inhalation and exhalation CT images. The proposed method was first applied to a numerical phantom XCAT with tumors and then applied to BH-PET image data for seven patients. The resultant tumor contrasts and the estimated motion vector fields were compared with those obtained by our previous method. Through those experiments we confirmed that the proposed method can provide an improved and more stable image quality for both RG and BH-PET images.

  17. Non-invasive assessment of congenital pulmonary vein stenosis in children using cardiac-non-gated CT with 64-slice technology

    International Nuclear Information System (INIS)

    Ou, Phalla; Marini, Davide; Celermajer, David S.; Agnoletti, Gabriella; Vouhe, Pascal; Sidi, Daniel; Bonnet, Damien; Brunelle, Francis

    2009-01-01

    Background: Management of congenital pulmonary vein stenosis is a diagnostic challenge. Echocardiography may be insufficient and thus cardiac catheterization remains the reference standard in this setting. The aim of the study was to investigate the accuracy of cardiac-non-gated CT using 64-slice technology in detecting congenital pulmonary vein stenosis in children. Materials and methods: CT examinations were consecutively performed from May 2005 to December 2006 in 13 children aged 1.5-12 months (median 5 months) for suspected congenital pulmonary vein stenosis. Cardiac-non-gated CT acquisitions were performed after the peripheral injection of contrast agent. Pulmonary veins were evaluated for their pattern of connectivity from the lung to the left atrium and for the presence of stenosis. CT findings of pulmonary vein stenosis were compared with combined findings available from echocardiography, catheterization and surgery. Results: Pulmonary veins from the right lung (n = 29) and left lung (n = 26) were evaluated as separate structures (N = 55). Of the 55 structures, 32 had surgical and/or catheterization data and 45 had echocardiography for comparison. CT visualized 100% (55/55) of the investigated structures, while echocardiography visualized 82% (45/55). In the 13 subjects CT identified 10 stenotic pulmonary veins. CT confirmed the echocardiography suspicion of pulmonary vein stenosis in 100% (7/7) and established a new diagnosis in 3 other patients. CT agreed with surgery/catheterization in 100% (10/10) of the available comparisons. Conclusion: Cardiac-non-gated CT assessed the pulmonary veins more completely than echocardiography and should be considered as a viable alternative for invasive pulmonary venography for detecting pulmonary vein stenosis in children.

  18. WE-FG-202-06: The Use of Hybrid PET MRI for Identifying the Presence of Cardiac Inflammation Following External Beam Irradiation

    International Nuclear Information System (INIS)

    El-Sherif, O; Xhaferllari, I; Battista, J; Sykes, J; Butler, J; Wisenberg, G; Prato, F; Gaede, S

    2016-01-01

    Purpose: To monitor the evolution of radiation-induced cardiac inflammation in a canine model using hybrid positron emission tomography (PET/magnetic resonance imaging (MRI). Methods: Research ethics approval was obtained for a longitudinal imaging study of 5 canines after cardiac irradiation. Animals were imaged at baseline, 3 months, 6 months, and 12 months post cardiac irradiation using a hybrid PET-MRI system (Biograph mMR, Siemens Healthcare). The imaging protocol was designed to assess changes in cardiac inflammation using 18 F-fluorodeoxyglucose ( 18 F-FDG) PET tracer. In order to image cardiac inflammation, the normal myocardial uptake of glucose was suppressed prior to the injection of 18 F-FDG. The suppression of glycolysis was achieved through; fasting (16–21 hours prior to the start of imaging) and an intravenous injection of heparin immediately followed by a 20% lipid infusion 20 min prior to the injection of 18 F-FDG. The standard uptake value (SUV) obtained from 17 myocardial regions were used to compare FDG scans. All animals received a simulation CT scan (GE Medical Systems) for radiation treatment planning. Radiation treatment plans were created using the Pinncale3 treatment planning system (Philips Radiation Oncology Systems) and designed to resemble the typical cardiac exposure during left-sided breast cancer radiotherapy. Cardiac irradiations were performed in a single fraction using a TrueBeam linear accelerator (Varian Medical Systems). Results: The delivered dose (mean ± standard error) to heart, left ventricle, and left anterior descending artery were 1.7±0.1 Gy, 2.7±0.1 Gy, and 5.5±0.3 Gy respectively. At these doses, a significant increase in 18 F-FDG uptake within the entire heart relative to baseline (1.1±0.02 g/ml) uptake was observed. 18 F-FDG uptake at 3 months, 6 months, and 12 months post irradiation were 1.8±0.03 g/ml, 2.4±0.06 g/ml, and 2.6±0.11 g/ml respectively. Conclusion: Low doses of limited cardiac irradiation

  19. WE-FG-202-06: The Use of Hybrid PET MRI for Identifying the Presence of Cardiac Inflammation Following External Beam Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    El-Sherif, O; Xhaferllari, I; Battista, J [Western University, London, ON (United Kingdom); London Regional Cancer Program, London, ON (United Kingdom); Sykes, J; Butler, J [Thames Valley Veterinary Services, London, Ontario (Canada); Lawson Health Research Institute, London, Ontario (Canada); Wisenberg, G; Prato, F [Western University, London, ON (United Kingdom); Lawson Health Research Institute, London, Ontario (Canada); Gaede, S [Western University, London, ON (United Kingdom); London Regional Cancer Program, London, ON (United Kingdom); Lawson Health Research Institute, London, Ontario (Canada)

    2016-06-15

    Purpose: To monitor the evolution of radiation-induced cardiac inflammation in a canine model using hybrid positron emission tomography (PET/magnetic resonance imaging (MRI). Methods: Research ethics approval was obtained for a longitudinal imaging study of 5 canines after cardiac irradiation. Animals were imaged at baseline, 3 months, 6 months, and 12 months post cardiac irradiation using a hybrid PET-MRI system (Biograph mMR, Siemens Healthcare). The imaging protocol was designed to assess changes in cardiac inflammation using {sup 18}F-fluorodeoxyglucose ({sup 18}F-FDG) PET tracer. In order to image cardiac inflammation, the normal myocardial uptake of glucose was suppressed prior to the injection of {sup 18}F-FDG. The suppression of glycolysis was achieved through; fasting (16–21 hours prior to the start of imaging) and an intravenous injection of heparin immediately followed by a 20% lipid infusion 20 min prior to the injection of {sup 18}F-FDG. The standard uptake value (SUV) obtained from 17 myocardial regions were used to compare FDG scans. All animals received a simulation CT scan (GE Medical Systems) for radiation treatment planning. Radiation treatment plans were created using the Pinncale3 treatment planning system (Philips Radiation Oncology Systems) and designed to resemble the typical cardiac exposure during left-sided breast cancer radiotherapy. Cardiac irradiations were performed in a single fraction using a TrueBeam linear accelerator (Varian Medical Systems). Results: The delivered dose (mean ± standard error) to heart, left ventricle, and left anterior descending artery were 1.7±0.1 Gy, 2.7±0.1 Gy, and 5.5±0.3 Gy respectively. At these doses, a significant increase in {sup 18}F-FDG uptake within the entire heart relative to baseline (1.1±0.02 g/ml) uptake was observed. {sup 18}F-FDG uptake at 3 months, 6 months, and 12 months post irradiation were 1.8±0.03 g/ml, 2.4±0.06 g/ml, and 2.6±0.11 g/ml respectively. Conclusion: Low doses of

  20. Investigations of new cardiac functional imaging using Fourier analysis of gated blood-pool study

    International Nuclear Information System (INIS)

    Maeda, H.; Takeda, K.; Nakagawa, T.; Yamaguchi, N.; Taguchi, M.; Konishi, T.; Hamada, M.

    1982-01-01

    A new cardiac functional imaging, using temporal Fourier analysis of 28-frame gated cardiac blood-pool studies, was developed. A time-activity curve of each pixel was approximated by its Fourier series. Approximation by the sum for terms to the 3rd frequency of its Fourier series was considered to be most reasonable because of having the least aberration due to statistical fluctuation and close agreement between the global left ventricular curve and the regional fitted curves in normal subjects. To evaluate the ventricular systolic and diastolic performances, 9 parameters were analyzed from thus fitted curves on a pixel-by-pixel basis and displayed on a colour CRT in 64x64 matrix form. In patients with hypertrophic obstructive cardiomyopathy and other cardiac lesions, detailed information on the regional ventricular systolic and diastolic performances was clearly visualized by this method, which was difficult to obtain from the usual functional images of phase and amplitude at the fundamental frequency alone

  1. Benefits of quantitative gated SPECT in evaluation of perioperative cardiac risk in noncardiac surgery

    International Nuclear Information System (INIS)

    Watanabe, Koji; Ohsumi, Yukio; Abe, Hirohiko; Hattori, Masahito; Minatoguchi, Shinya; Fujiwara, Hisayoshi

    2007-01-01

    Gated single-photon emission computed tomography (G-SPECT) was used to evaluate cardiac risk associated with noncardiac surgery and determine the benefits and indications of this technique for this type of surgery. Patients scheduled to undergo noncardiac surgery under the supervision of anesthesiologists and subjected to preoperative cardiac evaluation using G-SPECT during the 26-month period between June 2000 and August 2002 were followed for the presence/absence of cardiac events (id est (i.e.), cardiac death, myocardial infarction, unstable angina, congestive heart failure, or fatal arrhythmia) during surgery and the postoperative period until discharged. Relationships between the occurrence of cardiac events and preoperative G-SPECT findings were evaluated. A total of 39 patients underwent G-SPECT; 6 of the 39 exhibited abnormal ejection fraction (left ventricular ejection fraction, left ventricular ejection fraction (LVEF)≤50%) and end-systolic volume (end-systolic volume (ESV)≥50 ml). Surgery was suspended for three of these six patients and cardiac events developed in the remaining three patients. Both abnormal perfusion images (PI) and abnormal wall thickening (WT) were observed in all six patients. All six patients exhibited abnormal LVEF and/or ESV. Three patients had either abnormal PI or WT, and a cardiac event occurred in one of them. Of the five patients who experienced cardiac events during or after surgery, two exhibited a short run of ventricular tachycardia requiring a continuous administering of antiarrhythmic drugs, whereas the remaining three patients exhibited cardiac failure requiring inotropic support following surgery. The results of this study indicate that the occurrence of perioperative cardiac events can be predicted by considering the severity of expected surgical stress and preoperative G-SPECT findings for LVEF, PI, and WT. We conclude that G-SPECT is quite useful for cardiac risk assessment in patients undergoing noncardiac

  2. PET measurements of myocardial blood flow post myocardial infarction: Relationship to invasive and cardiac magnetic resonance studies and potential clinical applications.

    Science.gov (United States)

    Gewirtz, Henry

    2017-12-01

    This review focuses on clinical studies concerning assessment of coronary microvascular and conduit vessel function primarily in the context of acute and sub acute myocardial infarction (MI). The ability of quantitative PET measurements of myocardial blood flow (MBF) to delineate underlying pathophysiology and assist in clinical decision making in this setting is discussed. Likewise, considered are physiological metrics fractional flow reserve, coronary flow reserve, index of microvascular resistance (FFR, CFR, IMR) obtained from invasive studies performed in the cardiac catheterization laboratory, typically at the time of PCI for MI. The role both of invasive studies and cardiac magnetic resonance (CMR) imaging in assessing microvascular function, a key determinant of prognosis, is reviewed. The interface between quantitative PET MBF measurements and underlying pathophysiology, as demonstrated both by invasive and CMR methodology, is discussed in the context of optimal interpretation of the quantitative PET MBF exam and its potential clinical applications.

  3. Respiratory gating in positron emission tomography: A quantitative comparison of different gating schemes

    International Nuclear Information System (INIS)

    Dawood, Mohammad; Buether, Florian; Lang, Norbert; Schober, Otmar; Schaefers, Klaus P

    2007-01-01

    Respiratory gating is used for reducing the effects of breathing motion in a wide range of applications from radiotherapy treatment to diagnostical imaging. Different methods are feasible for respiratory gating. In this study seven gating methods were developed and tested on positron emission tomography (PET) listmode data. The results of seven patient studies were compared quantitatively with respect to motion and noise. (1) Equal and (2) variable time-based gating methods use only the time information of the breathing cycle to define respiratory gates. (3) Equal and (4) variable amplitude-based gating approaches utilize the amplitude of the respiratory signal. (5) Cycle-based amplitude gating is a combination of time and amplitude-based techniques. A baseline correction was applied to methods (3) and (4) resulting in two new approaches: Baseline corrected (6) equal and (7) variable amplitude-based gating. Listmode PET data from seven patients were acquired together with a respiratory signal. Images were reconstructed applying the seven gating methods. Two parameters were used to quantify the results: Motion was measured as the displacement of the heart due to respiration and noise was defined as the standard deviation of pixel intensities in a background region. The amplitude-based approaches (3) and (4) were superior to the time-based methods (1) and (2). The improvement in capturing the motion was more than 30% (up to 130%) in all subjects. The variable time (2) and amplitude (4) methods had a more uniform noise distribution among all respiratory gates compared to equal time (1) and amplitude (3) methods. Baseline correction did not improve the results. Out of seven different respiratory gating approaches, the variable amplitude method (4) captures the respiratory motion best while keeping a constant noise level among all respiratory phases

  4. Gated cardiac imaging: manual calculations and observations of left ventricular ejection fraction

    International Nuclear Information System (INIS)

    Hawkins, T.; Keavey, P.M.

    1984-01-01

    Using gamma camera imaging, the fixed region and moving region methods of calculating left ventricular ejection fraction were studied. Data were obtained from gated blood pool studies on 125 cardiac patients with myocardial infarcts of varying extent and location. Ejection fractions ranged from 10 to 76%. The left anterior oblique angulation for optimal visualisation of the ventricles showed considerable patient variation. The authors conclude that a fixed angulation cannot be recommended and that there is little to justify it. Where the septum is not seen distinctly during setting up, a larger rather than smaller angle is generally advised. (U.K.)

  5. High-resolution imaging of pulmonary ventilation and perfusion with 68Ga-VQ respiratory gated (4-D) PET/CT

    International Nuclear Information System (INIS)

    Callahan, Jason; Hofman, Michael S.; Siva, Shankar; Kron, Tomas; Schneider, Michal E.; Binns, David; Eu, Peter; Hicks, Rodney J.

    2014-01-01

    Our group has previously reported on the use of 68 Ga-ventilation/perfusion (VQ) PET/CT scanning for the diagnosis of pulmonary embolism. We describe here the acquisition methodology for 68 Ga-VQ respiratory gated (4-D) PET/CT and the effects of respiratory motion on image coregistration in VQ scanning. A prospective study was performed in 15 patients with non-small-cell lung cancer. 4-D PET and 4-D CT images were acquired using an infrared marker on the patient's abdomen as a surrogate for breathing motion following inhalation of Galligas and intravenous administration of 68 Ga-macroaggregated albumin. Images were reconstructed with phase-matched attenuation correction. The lungs were contoured on CT and PET VQ images during free-breathing (FB) and at maximum inspiration (Insp) and expiration (Exp). The similarity between PET and CT volumes was measured using the Dice coefficient (DC) comparing the following groups; (1) FB-PET/CT, (2) InspPET/InspCT, (3) ExpPET/Exp CT, and (4) FB-PET/AveCT. A repeated measures one-way ANOVA with multiple comparison Tukey tests were performed to evaluate any difference between the groups. Diaphragmatic motion in the superior-inferior direction on the 4-D CT scan was also measured. 4-D VQ scanning was successful in all patients without additional acquisition time compared to the nongated technique. The highest volume overlap was between ExpPET and ExpCT and between FB-PET and AveCT with a DC of 0.82 and 0.80 for ventilation and perfusion, respectively. This was significantly better than the DC comparing the other groups (0.78-0.79, p 68 Ga-VQ 4-D PET/CT is feasible and the blurring caused by respiratory motion is well corrected with 4-D acquisition, which principally reduces artefact at the lung bases. The images with the highest spatial overlap were the combined expiration phase or FB PET and average CT. With higher resolution than SPECT/CT, the PET/CT technique has a broad range of potential clinical applications including

  6. Assessment of left ventricular function by gated cardiac blood-pool emission computed tomography using a rotating gamma camera

    International Nuclear Information System (INIS)

    Narita, Michihiro; Kurihara, Tadashi; Murano, Kenichi; Usami, Masahisa; Honda, Minoru

    1991-01-01

    To elucidate the usefulness of gated cardiac blood-pool single photon emission CT (SPECT) with Tc-99m for the evaluation of left ventricular (LV) global and regional functions, 18 patients with coronary artery disease were studied. Thirty-two gated projection images were obtained over 360-degree at 16 frames per cardiac cycle. As LV volume was calculated by integrating the numbers of voxels which constituted LV and multiplying by the volume of a single voxel (0.1143 ml), we performed phantom studies to determine the appropriate cut-off level to detect LV outline. These cut-off levels were affected by the background activity and organ volume itself. So we constructed Volume-Cut-Level-Curve at each background activity. In clinical studies, short axis images which constituted LV were selected and provisional LV volumes were calculated at the cut-off levels of 45, 50 and 55%. These volumes were plotted on the Volume-Cut-Level-Curve and the true cut-off levels were obtained to calculate LV end-diastolic or end-systolic volume (EDV, ESV). The cut-off levels were different at every patient and ED or ES. EDV, ESV and LV ejection fraction obtained by SPECT were correlatd well with those obtained by contrast ventriculography (LVG) (r=0.89, 0.94, 0.94 each, p<0.01). For the LV wall motion analysis, LVGs obtained at two projections were compared with SPECT or gated cardiac blood-pool planar imaging (Planar) in 5 segments. In addition to visual comparison, wall motion scores (WMS) based on the degree of wall motion abnormality were calculated in each segment. Correlation of WMS between LVG and SPECT (r=0.84) was significantly (p<0.01) superior to that between LVG and Planar (r=0.62). Especially in SPECT, wall motion analyses at septal and infero-posterior segments were superior to those in Planar. Although gated SPECT requires relatively long time to perform, it is a useful method to detect LV global and regional functions. (author)

  7. An attenuation correction method for PET/CT images

    International Nuclear Information System (INIS)

    Ue, Hidenori; Yamazaki, Tomohiro; Haneishi, Hideaki

    2006-01-01

    In PET/CT systems, accurate attenuation correction can be achieved by creating an attenuation map from an X-ray CT image. On the other hand, respiratory-gated PET acquisition is an effective method for avoiding motion blurring of the thoracic and abdominal organs caused by respiratory motion. In PET/CT systems employing respiratory-gated PET, using an X-ray CT image acquired during breath-holding for attenuation correction may have a large effect on the voxel values, especially in regions with substantial respiratory motion. In this report, we propose an attenuation correction method in which, as the first step, a set of respiratory-gated PET images is reconstructed without attenuation correction, as the second step, the motion of each phase PET image from the PET image in the same phase as the CT acquisition timing is estimated by the previously proposed method, as the third step, the CT image corresponding to each respiratory phase is generated from the original CT image by deformation according to the motion vector maps, and as the final step, attenuation correction using these CT images and reconstruction are performed. The effectiveness of the proposed method was evaluated using 4D-NCAT phantoms, and good stability of the voxel values near the diaphragm was observed. (author)

  8. Cluster computing software for GATE simulations

    International Nuclear Information System (INIS)

    Beenhouwer, Jan de; Staelens, Steven; Kruecker, Dirk; Ferrer, Ludovic; D'Asseler, Yves; Lemahieu, Ignace; Rannou, Fernando R.

    2007-01-01

    Geometry and tracking (GEANT4) is a Monte Carlo package designed for high energy physics experiments. It is used as the basis layer for Monte Carlo simulations of nuclear medicine acquisition systems in GEANT4 Application for Tomographic Emission (GATE). GATE allows the user to realistically model experiments using accurate physics models and time synchronization for detector movement through a script language contained in a macro file. The downside of this high accuracy is long computation time. This paper describes a platform independent computing approach for running GATE simulations on a cluster of computers in order to reduce the overall simulation time. Our software automatically creates fully resolved, nonparametrized macros accompanied with an on-the-fly generated cluster specific submit file used to launch the simulations. The scalability of GATE simulations on a cluster is investigated for two imaging modalities, positron emission tomography (PET) and single photon emission computed tomography (SPECT). Due to a higher sensitivity, PET simulations are characterized by relatively high data output rates that create rather large output files. SPECT simulations, on the other hand, have lower data output rates but require a long collimator setup time. Both of these characteristics hamper scalability as a function of the number of CPUs. The scalability of PET simulations is improved here by the development of a fast output merger. The scalability of SPECT simulations is improved by greatly reducing the collimator setup time. Accordingly, these two new developments result in higher scalability for both PET and SPECT simulations and reduce the computation time to more practical values

  9. [11C]-Acetoacetate PET imaging: a potential early marker for cardiac heart failure

    International Nuclear Information System (INIS)

    Croteau, Etienne; Tremblay, Sébastien; Gascon, Suzanne; Dumulon-Perreault, Véronique; Labbé, Sébastien M.; Rousseau, Jacques A.; Cunnane, Stephen C.; Carpentier, André C.; Bénard, François; Lecomte, Roger

    2014-01-01

    The ketone body acetoacetate could be used as an alternate nutrient for the heart, and it also has the potential to improve cardiac function in an ischemic–reperfusion model or reduce the mitochondrial production of oxidative stress involved in cardiotoxicity. In this study, [ 11 C]-acetoacetate was investigated as an early marker of intracellular damage in heart failure. Methods: A rat cardiotoxicity heart failure model was induced by doxorubicin, Dox(+). [ 14 C]-Acetoacetate, a non-positron (β −) emitting radiotracer, was used to characterize the arterial blood input function and myocardial mitochondrial uptake. Afterward, [ 11 C]-acetoacetate (β +) myocardial PET images were obtained for kinetic analysis and heart function assessment in control Dox(−) (n = 15) and treated Dox(+) (n = 6) rats. The uptake rate (K 1 ) and myocardial clearance rate (k 2 or k mono ) were extracted. Results: [ 14 C]-Acetoacetate in the blood was increased in Dox(+), from 2 min post-injection until the last withdrawal point when the heart was harvested, as well as the uptake in the heart and myocardial mitochondria (unpaired t-test, p < 0.05). PET kinetic analysis of [ 11 C]-acetoacetate showed that rate constants K 1 , k 2 and k mono were decreased in Dox(+) (p < 0.05) combined with a reduction of 24% of the left ventricular ejection fraction (p < 0.001). Conclusion: Radioactive acetoacetate ex vivo analysis [ 14 C], and in vivo kinetic [ 11 C] studies provided evidence that [ 11 C]-acetoacetate can assess heart failure Dox(+). Contrary to myocardial flow reserve (rest–stress protocol), [ 11 C]-acetoacetate can be used to assess reduced kinetic rate constants without requirement of hyperemic stress response. The proposed [ 11 C]-acetoacetate cardiac radiotracer in the investigation of heart disease is novel and paves the way to a potential role for [ 11 C]-acetoacetate in cardiac pathophysiology

  10. Myocardial blood flow quantification by Rb-82 cardiac PET/CT: A detailed reproducibility study between two semi-automatic analysis programs.

    OpenAIRE

    Dunet, V.; Klein, R.; Allenbach, G.; Renaud, J.; deKemp, R.A.; Prior, J.O.

    2016-01-01

    Background Several analysis software packages for myocardial blood flow (MBF) quantification from cardiac PET studies exist, but they have not been compared using concordance analysis, which can characterize precision and bias separately. Reproducible measurements are needed for quantification to fully develop its clinical potential. Methods Fifty-one patients underwent dynamic Rb-82 PET at rest and during adenosine stress. Data were processed with PMOD and FlowQuant (Lortie model). MBF and m...

  11. Hybrid cardiac imaging: SPECT/CT and PET/CT. A joint position statement by the European Association of Nuclear Medicine (EANM), the European Society of Cardiac Radiology (ESCR) and the European Council of Nuclear Cardiology (ECNC)

    DEFF Research Database (Denmark)

    Flotats, Albert; Gutberlet, Matthias; Knuuti, Juhani

    2011-01-01

    . The European Association of Nuclear Medicine (EANM), the European Society of Cardiac Radiology (ESCR) and the European Council of Nuclear Cardiology (ECNC) in this paper want to present a position statement of the institutions on the current roles of SPECT/CT and PET/CT hybrid cardiac imaging in patients...

  12. SU-C-9A-06: The Impact of CT Image Used for Attenuation Correction in 4D-PET

    International Nuclear Information System (INIS)

    Cui, Y; Bowsher, J; Yan, S; Cai, J; Das, S; Yin, F

    2014-01-01

    Purpose: To evaluate the appropriateness of using 3D non-gated CT image for attenuation correction (AC) in a 4D-PET (gated PET) imaging protocol used in radiotherapy treatment planning simulation. Methods: The 4D-PET imaging protocol in a Siemens PET/CT simulator (Biograph mCT, Siemens Medical Solutions, Hoffman Estates, IL) was evaluated. CIRS Dynamic Thorax Phantom (CIRS Inc., Norfolk, VA) with a moving glass sphere (8 mL) in the middle of its thorax portion was used in the experiments. The glass was filled with 18 F-FDG and was in a longitudinal motion derived from a real patient breathing pattern. Varian RPM system (Varian Medical Systems, Palo Alto, CA) was used for respiratory gating. Both phase-gating and amplitude-gating methods were tested. The clinical imaging protocol was modified to use three different CT images for AC in 4D-PET reconstruction: first is to use a single-phase CT image to mimic actual clinical protocol (single-CT-PET); second is to use the average intensity projection CT (AveIP-CT) derived from 4D-CT scanning (AveIP-CT-PET); third is to use 4D-CT image to do the phase-matched AC (phase-matching- PET). Maximum SUV (SUVmax) and volume of the moving target (glass sphere) with threshold of 40% SUVmax were calculated for comparison between 4D-PET images derived with different AC methods. Results: The SUVmax varied 7.3%±6.9% over the breathing cycle in single-CT-PET, compared to 2.5%±2.8% in AveIP-CT-PET and 1.3%±1.2% in phasematching PET. The SUVmax in single-CT-PET differed by up to 15% from those in phase-matching-PET. The target volumes measured from single- CT-PET images also presented variations up to 10% among different phases of 4D PET in both phase-gating and amplitude-gating experiments. Conclusion: Attenuation correction using non-gated CT in 4D-PET imaging is not optimal process for quantitative analysis. Clinical 4D-PET imaging protocols should consider phase-matched 4D-CT image if available to achieve better accuracy

  13. SU-C-9A-06: The Impact of CT Image Used for Attenuation Correction in 4D-PET

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Y; Bowsher, J; Yan, S; Cai, J; Das, S; Yin, F [Duke University Medical Center, Durham, NC (United States)

    2014-06-01

    Purpose: To evaluate the appropriateness of using 3D non-gated CT image for attenuation correction (AC) in a 4D-PET (gated PET) imaging protocol used in radiotherapy treatment planning simulation. Methods: The 4D-PET imaging protocol in a Siemens PET/CT simulator (Biograph mCT, Siemens Medical Solutions, Hoffman Estates, IL) was evaluated. CIRS Dynamic Thorax Phantom (CIRS Inc., Norfolk, VA) with a moving glass sphere (8 mL) in the middle of its thorax portion was used in the experiments. The glass was filled with {sup 18}F-FDG and was in a longitudinal motion derived from a real patient breathing pattern. Varian RPM system (Varian Medical Systems, Palo Alto, CA) was used for respiratory gating. Both phase-gating and amplitude-gating methods were tested. The clinical imaging protocol was modified to use three different CT images for AC in 4D-PET reconstruction: first is to use a single-phase CT image to mimic actual clinical protocol (single-CT-PET); second is to use the average intensity projection CT (AveIP-CT) derived from 4D-CT scanning (AveIP-CT-PET); third is to use 4D-CT image to do the phase-matched AC (phase-matching- PET). Maximum SUV (SUVmax) and volume of the moving target (glass sphere) with threshold of 40% SUVmax were calculated for comparison between 4D-PET images derived with different AC methods. Results: The SUVmax varied 7.3%±6.9% over the breathing cycle in single-CT-PET, compared to 2.5%±2.8% in AveIP-CT-PET and 1.3%±1.2% in phasematching PET. The SUVmax in single-CT-PET differed by up to 15% from those in phase-matching-PET. The target volumes measured from single- CT-PET images also presented variations up to 10% among different phases of 4D PET in both phase-gating and amplitude-gating experiments. Conclusion: Attenuation correction using non-gated CT in 4D-PET imaging is not optimal process for quantitative analysis. Clinical 4D-PET imaging protocols should consider phase-matched 4D-CT image if available to achieve better accuracy.

  14. Calculation of left ventricular volumes and ejection fraction from dynamic cardiac-gated 15O-water PET/CT: 5D-PET

    OpenAIRE

    Jonny Nordström; Tanja Kero; Hendrik Johannes Harms; Charles Widström; Frank A. Flachskampf; Jens Sörensen; Mark Lubberink

    2017-01-01

    BACKGROUND: Quantitative measurement of myocardial blood flow (MBF) is of increasing interest in the clinical assessment of patients with suspected coronary artery disease (CAD). (15)O-water positron emission tomography (PET) is considered the gold standard for non-invasive MBF measurements. However, calculation of left ventricular (LV) volumes and ejection fraction (EF) is not possible from standard (15)O-water uptake images. The purpose of the present work was to investigate the possibility...

  15. 18F-FDG PET-CT respiratory gating in characterization of pulmonary lesions. Approximation towards clinical indications

    International Nuclear Information System (INIS)

    Garcia Vicente, A.M.; Soriano Castrejon, A.M.; Talavera Rubio, M.P.; Leon Martin, A.A.; Palomar Munoz, A.M.; Pilkington Woll, J.P.; Poblete Garcia, V.M.

    2010-01-01

    The aim of this study was to evaluate the effect of the 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)-CT respiratory gating (4D) study in the correct documentation of pulmonary lesions with faint uptake in standard PET-CT. Forty-two pulmonary lesions with a low or no detectable uptake of FDG (standardized uptake value (SUV) max max was determined for each lesion in both studies. For the 4D studies, we selected the SUV max in respiratory period with the highest uptake ('best bin'). We calculated the SUV max percentage difference between 3D and 4D PET-CT (% difference=SUV max 4D-SUV max 3D/SUV max 3D x 100) and the relation of this value with the size and locations of the lesions. In 4D study, any lesion with SUV max ≥2.5 was classified as malignant. We assessed the changes of lesion classification (from benign to malignant) applying the 4D technique. The final diagnosis was obtained by histological assessment or clinical and radiological follow-up longer than 12 months. Forty out of 42 lesions showed an increase of SUV max in the 4D study with respect to 3D. The mean SUV max in the 3D and 4D PET-CT studies were 1.33 (±0.59) and 2.26 (±0.87), respectively. The SUV max percentage difference mean between both techniques was 83.3% (±80.81). The smaller the lesion the greater was the SUV max percentage difference (P<0.05). No differences were observed depending on the location of the lesion. In 40% of cases, there was a change in the final classification of lesions from benign to malignant. In the final diagnosis, 24 lesions were malignant. 4D PET-CT diagnosed correctly the 52% of them. The 4D PET-CT study permitted a better characterization of malignant lung lesions compared with the standard PET-CT, because of its higher sensitivity. 4D PET-CT is a recommendable technique in the early diagnosis of malignant lesions. (author)

  16. Usefulness of abdominal belt for restricting respiratory cardiac motion and improving image quality in myocardial perfusion PET.

    Science.gov (United States)

    Ichikawa, Yasutaka; Tomita, Yoya; Ishida, Masaki; Kobayashi, Shigeki; Takeda, Kan; Sakuma, Hajime

    2018-04-01

    The current study evaluated the usefulness of a belt technique for restricting respiratory motion of the heart and for improving image quality of 13 N-ammonia myocardial PET/CT, and it assessed the tolerability of the belt technique in the clinical setting. Myocardial 13 N-ammonia PET/CT scanning was performed in 8 volunteers on Discovery PET/CT 690 with an optical respiratory motion tracking system. Emission scans were performed with and without an abdominal belt. The amplitude of left ventricular (LV) respiratory motion was measured on respiratory-gated PET images. The degree of erroneous decreases in regional myocardial uptake was visually assessed on ungated PET images using a 5-point scale (0 = normal, 1/2/3 = mild/moderate/severe decrease, 4 = defect). The tolerability of the belt technique was evaluated in 53 patients. All subjects tolerated the belt procedure. The amplitude of the LV respiratory motion decreased significantly with the belt (8.1 ± 7.1 vs 12.1 ± 6.1 mm, P = .0078). The belt significantly improved the image quality scores in the anterior (0.29 ± 0.81 vs 0.71 ± 1.04, P = .015) and inferior (0.33 ± 0.92 vs 1.04 ± 1.04, P PET/CT, and it is well tolerated by patients.

  17. Low dose prospective ECG-gated delayed enhanced dual-source computed tomography in reperfused acute myocardial infarction comparison with cardiac magnetic resonance

    International Nuclear Information System (INIS)

    Wang Rui; Zhang Zhaoqi; Xu Lei; Ma Qin; He Yi; Lu Dongxu; Yu Wei; Fan Zhanming

    2011-01-01

    Purpose: To determine whether prospective electrocardiogram (ECG)-gated delayed contrast-enhanced dual-source computed tomography (DCE-DSCT) can accurately delineate the extension of myocardial infarction (MI) compared with delayed enhanced cardiac MR (DE-MR). Material and methods: Eleven patients were examined using dual-source CT and cardiac MR in 2 weeks after a first reperfused MI. DCE-DSCT scan protocol was performed with prospective ECG-gating sequential scan model 7 min after contrast administration. In a 17-model, infarcted myocardium detected by DE-MR was categorized as transmural and subendocardial extension. Segment of infarcted location and graded transmurality were compared between DCE-MDCT and DE-MR. Results: In all eleven patients, diagnostic quality was obtained for depicting delayed enhanced myocardium. Agreement between DCE-DSCT and MR was good on myocardial segment based comparison (kappa = 0.85, p < 0.001), and on transmural and subendocardial infarction type comparison (kappa = 0.82, p < 0.001, kappa = 0.52, p < 0.001, respectively). CT value was higher on infarcted region than that of normal region (100.02 ± 9.57 HU vs. 72.63 ± 7.32 HU, p < 0.001). Radiation dose of prospectively ECG-gating protocol were 0.99 ± 0.08 mSv (0.82-1.19 mSv). Conclusions: Prospective ECG-gated DCE-DSCT can accurately assess the extension and the patterns of myocardial infarction with low radiation dose.

  18. Low dose prospective ECG-gated delayed enhanced dual-source computed tomography in reperfused acute myocardial infarction comparison with cardiac magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Wang Rui, E-mail: rui_wang1979@yahoo.cn [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China); Zhang Zhaoqi, E-mail: zhaoqi5000@vip.sohu.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China); Xu Lei, E-mail: leixu2001@hotmail.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China); Ma Qin, E-mail: tel1367@gmail.com [Department of Emergency, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China); He Yi, E-mail: heyi139@sina.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China); Lu Dongxu, E-mail: larry.hi@163.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China); Yu Wei, E-mail: yuwei02@gmail.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China); Fan Zhanming, E-mail: fanzm120@tom.com [Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 100029 Beijing (China)

    2011-11-15

    Purpose: To determine whether prospective electrocardiogram (ECG)-gated delayed contrast-enhanced dual-source computed tomography (DCE-DSCT) can accurately delineate the extension of myocardial infarction (MI) compared with delayed enhanced cardiac MR (DE-MR). Material and methods: Eleven patients were examined using dual-source CT and cardiac MR in 2 weeks after a first reperfused MI. DCE-DSCT scan protocol was performed with prospective ECG-gating sequential scan model 7 min after contrast administration. In a 17-model, infarcted myocardium detected by DE-MR was categorized as transmural and subendocardial extension. Segment of infarcted location and graded transmurality were compared between DCE-MDCT and DE-MR. Results: In all eleven patients, diagnostic quality was obtained for depicting delayed enhanced myocardium. Agreement between DCE-DSCT and MR was good on myocardial segment based comparison (kappa = 0.85, p < 0.001), and on transmural and subendocardial infarction type comparison (kappa = 0.82, p < 0.001, kappa = 0.52, p < 0.001, respectively). CT value was higher on infarcted region than that of normal region (100.02 {+-} 9.57 HU vs. 72.63 {+-} 7.32 HU, p < 0.001). Radiation dose of prospectively ECG-gating protocol were 0.99 {+-} 0.08 mSv (0.82-1.19 mSv). Conclusions: Prospective ECG-gated DCE-DSCT can accurately assess the extension and the patterns of myocardial infarction with low radiation dose.

  19. Full modelling of the MOSAIC animal PET system based on the GATE Monte Carlo simulation code

    International Nuclear Information System (INIS)

    Merheb, C; Petegnief, Y; Talbot, J N

    2007-01-01

    Positron emission tomography (PET) systems dedicated to animal imaging are now widely used for biological studies. The scanner performance strongly depends on the design and the characteristics of the system. Many parameters must be optimized like the dimensions and type of crystals, geometry and field-of-view (FOV), sampling, electronics, lightguide, shielding, etc. Monte Carlo modelling is a powerful tool to study the effect of each of these parameters on the basis of realistic simulated data. Performance assessment in terms of spatial resolution, count rates, scatter fraction and sensitivity is an important prerequisite before the model can be used instead of real data for a reliable description of the system response function or for optimization of reconstruction algorithms. The aim of this study is to model the performance of the Philips Mosaic(TM) animal PET system using a comprehensive PET simulation code in order to understand and describe the origin of important factors that influence image quality. We use GATE, a Monte Carlo simulation toolkit for a realistic description of the ring PET model, the detectors, shielding, cap, electronic processing and dead times. We incorporate new features to adjust signal processing to the Anger logic underlying the Mosaic(TM) system. Special attention was paid to dead time and energy spectra descriptions. Sorting of simulated events in a list mode format similar to the system outputs was developed to compare experimental and simulated sensitivity and scatter fractions for different energy thresholds using various models of phantoms describing rat and mouse geometries. Count rates were compared for both cylindrical homogeneous phantoms. Simulated spatial resolution was fitted to experimental data for 18 F point sources at different locations within the FOV with an analytical blurring function for electronic processing effects. Simulated and measured sensitivities differed by less than 3%, while scatter fractions agreed

  20. Monte Carlo simulations in small animal PET imaging

    Energy Technology Data Exchange (ETDEWEB)

    Branco, Susana [Universidade de Lisboa, Faculdade de Ciencias, Instituto de Biofisica e Engenharia Biomedica, Lisbon (Portugal)], E-mail: susana.silva@fc.ul.pt; Jan, Sebastien [Service Hospitalier Frederic Joliot, CEA/DSV/DRM, Orsay (France); Almeida, Pedro [Universidade de Lisboa, Faculdade de Ciencias, Instituto de Biofisica e Engenharia Biomedica, Lisbon (Portugal)

    2007-10-01

    This work is based on the use of an implemented Positron Emission Tomography (PET) simulation system dedicated for small animal PET imaging. Geant4 Application for Tomographic Emission (GATE), a Monte Carlo simulation platform based on the Geant4 libraries, is well suited for modeling the microPET FOCUS system and to implement realistic phantoms, such as the MOBY phantom, and data maps from real examinations. The use of a microPET FOCUS simulation model with GATE has been validated for spatial resolution, counting rates performances, imaging contrast recovery and quantitative analysis. Results from realistic studies of the mouse body using {sup -}F and [{sup 18}F]FDG imaging protocols are presented. These simulations include the injection of realistic doses into the animal and realistic time framing. The results have shown that it is possible to simulate small animal PET acquisitions under realistic conditions, and are expected to be useful to improve the quantitative analysis in PET mouse body studies.

  1. Pediatric 320-row cardiac computed tomography using electrocardiogram-gated model-based full iterative reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Shirota, Go; Maeda, Eriko; Namiki, Yoko; Bari, Razibul; Abe, Osamu [The University of Tokyo, Department of Radiology, Graduate School of Medicine, Tokyo (Japan); Ino, Kenji [The University of Tokyo Hospital, Imaging Center, Tokyo (Japan); Torigoe, Rumiko [Toshiba Medical Systems, Tokyo (Japan)

    2017-10-15

    Full iterative reconstruction algorithm is available, but its diagnostic quality in pediatric cardiac CT is unknown. To compare the imaging quality of two algorithms, full and hybrid iterative reconstruction, in pediatric cardiac CT. We included 49 children with congenital cardiac anomalies who underwent cardiac CT. We compared quality of images reconstructed using the two algorithms (full and hybrid iterative reconstruction) based on a 3-point scale for the delineation of the following anatomical structures: atrial septum, ventricular septum, right atrium, right ventricle, left atrium, left ventricle, main pulmonary artery, ascending aorta, aortic arch including the patent ductus arteriosus, descending aorta, right coronary artery and left main trunk. We evaluated beam-hardening artifacts from contrast-enhancement material using a 3-point scale, and we evaluated the overall image quality using a 5-point scale. We also compared image noise, signal-to-noise ratio and contrast-to-noise ratio between the algorithms. The overall image quality was significantly higher with full iterative reconstruction than with hybrid iterative reconstruction (3.67±0.79 vs. 3.31±0.89, P=0.0072). The evaluation scores for most of the gross structures were higher with full iterative reconstruction than with hybrid iterative reconstruction. There was no significant difference between full and hybrid iterative reconstruction for the presence of beam-hardening artifacts. Image noise was significantly lower in full iterative reconstruction, while signal-to-noise ratio and contrast-to-noise ratio were significantly higher in full iterative reconstruction. The diagnostic quality was superior in images with cardiac CT reconstructed with electrocardiogram-gated full iterative reconstruction. (orig.)

  2. Pediatric 320-row cardiac computed tomography using electrocardiogram-gated model-based full iterative reconstruction

    International Nuclear Information System (INIS)

    Shirota, Go; Maeda, Eriko; Namiki, Yoko; Bari, Razibul; Abe, Osamu; Ino, Kenji; Torigoe, Rumiko

    2017-01-01

    Full iterative reconstruction algorithm is available, but its diagnostic quality in pediatric cardiac CT is unknown. To compare the imaging quality of two algorithms, full and hybrid iterative reconstruction, in pediatric cardiac CT. We included 49 children with congenital cardiac anomalies who underwent cardiac CT. We compared quality of images reconstructed using the two algorithms (full and hybrid iterative reconstruction) based on a 3-point scale for the delineation of the following anatomical structures: atrial septum, ventricular septum, right atrium, right ventricle, left atrium, left ventricle, main pulmonary artery, ascending aorta, aortic arch including the patent ductus arteriosus, descending aorta, right coronary artery and left main trunk. We evaluated beam-hardening artifacts from contrast-enhancement material using a 3-point scale, and we evaluated the overall image quality using a 5-point scale. We also compared image noise, signal-to-noise ratio and contrast-to-noise ratio between the algorithms. The overall image quality was significantly higher with full iterative reconstruction than with hybrid iterative reconstruction (3.67±0.79 vs. 3.31±0.89, P=0.0072). The evaluation scores for most of the gross structures were higher with full iterative reconstruction than with hybrid iterative reconstruction. There was no significant difference between full and hybrid iterative reconstruction for the presence of beam-hardening artifacts. Image noise was significantly lower in full iterative reconstruction, while signal-to-noise ratio and contrast-to-noise ratio were significantly higher in full iterative reconstruction. The diagnostic quality was superior in images with cardiac CT reconstructed with electrocardiogram-gated full iterative reconstruction. (orig.)

  3. A knowledge-based method for reducing attenuation artefacts caused by cardiac appliances in myocardial PET/CT

    International Nuclear Information System (INIS)

    Hamill, James J; Brunken, Richard C; Bybel, Bohdan; DiFilippo, Frank P; Faul, David D

    2006-01-01

    Attenuation artefacts due to implanted cardiac defibrillator leads have previously been shown to adversely impact cardiac PET/CT imaging. In this study, the severity of the problem is characterized, and an image-based method is described which reduces the resulting artefact in PET. Automatic implantable cardioverter defibrillator (AICD) leads cause a moving-metal artefact in the CT sections from which the PET attenuation correction factors (ACFs) are derived. Fluoroscopic cine images were measured to demonstrate that the defibrillator's highly attenuating distal shocking coil moves rhythmically across distances on the order of 1 cm. Rhythmic motion of this magnitude was created in a phantom with a moving defibrillator lead. A CT study of the phantom showed that the artefact contained regions of incorrect, very high CT values and adjacent regions of incorrect, very low CT values. The study also showed that motion made the artefact more severe. A knowledge-based metal artefact reduction method (MAR) is described that reduces the magnitude of the error in the CT images, without use of the corrupted sinograms. The method modifies the corrupted image through a sequence of artefact detection procedures, morphological operations, adjustments of CT values and three-dimensional filtering. The method treats bone the same as metal. The artefact reduction method is shown to run in a few seconds, and is validated by applying it to a series of phantom studies in which reconstructed PET tracer distribution values are wrong by as much as 60% in regions near the CT artefact when MAR is not applied, but the errors are reduced to about 10% of expected values when MAR is applied. MAR changes PET image values by a few per cent in regions not close to the artefact. The changes can be larger in the vicinity of bone. In patient studies, the PET reconstruction without MAR sometimes results in anomalously high values in the infero-septal wall. Clinical performance of MAR is assessed by two

  4. Impact of a new respiratory amplitude-based gating technique in evaluation of upper abdominal PET lesions

    Energy Technology Data Exchange (ETDEWEB)

    Van Der Gucht, Axel, E-mail: axel.vandergucht@gmail.com [Department of Nuclear Medicine, Centre Hospitalier Princesse Grace, Monaco (Monaco); Serrano, Benjamin [Department of Medical Physics, Centre Hospitalier Princesse Grace, Monaco (Monaco); Hugonnet, Florent; Paulmier, Benoît [Department of Nuclear Medicine, Centre Hospitalier Princesse Grace, Monaco (Monaco); Garnier, Nicolas [Department of Medical Physics, Centre Hospitalier Princesse Grace, Monaco (Monaco); Faraggi, Marc [Department of Nuclear Medicine, Centre Hospitalier Princesse Grace, Monaco (Monaco)

    2014-03-15

    PET acquisition requires several minutes which can lead to respiratory motion blurring, to increase partial volume effect and SUV under-estimation. To avoid these artifacts, conventional 10-min phase-based respiratory gating (PBRG) can be performed but is time-consuming and difficult with a non-compliant patient. We evaluated an automatic amplitude-based gating method (AABG) which keeps 35% of the counts at the end of expiration to minimize respiratory motion. We estimated the impact of AABG on upper abdominal lesion detectability, quantification and patient management. Methods: We consecutively included 31 patients (82 hepatic and 25 perihepatic known lesions). Each patient underwent 3 acquisitions on a Siemens Biograph mCT (4 rings and time-of-flight): a standard free-breathing whole-body (SWB, 5–7 steps/2.5 min per step, 3.3 ± 0.4 MBq/kg of 18F-FDG), a 10-min PBRG with six bins and a 5-min AABG method. All gated acquisitions were performed with an ANZAI respiratory gating system. SUV{sub max} and target to background ratio (TBR, defined as the maximum SUV of the lesion divided by the mean SUV of a region of interest drawn in healthy liver) were compared. Results: All 94 lesions in SWB images were detected in the gated images. 10-min PBRG and 5-min AABG acquisitions respectively revealed 9 and 13 new lesions and relocated 7 and 8 lesions. Four lesions revealed by 5-min AABG were missed by 10-min PBRG in 3 non-compliant patients. Both gated methods failed to relocate 2 lesions seen on SWB acquisition. Compared to SWB, TBR increased significantly with 10-min PBRG and with 5-min AABG (respectively 41 ± 59%, p = 4.10–3 and 66 ± 75%, p = 6.10–5) whereas SUV{sub max} did not (respectively 14 ± 43%, p = 0.29 with 10-min PBRG, and 24 ± 46%, p = 0.11 with 5-min AABG). Conclusion: The AABG is a fast and a user-friendly respiratory gating method to increase detectability and quantification of upper abdominal lesions compared to the conventional PBRG procedure and

  5. Evaluation of a low-carbohydrate diet-based preparation protocol without fasting for cardiac PET/MR imaging.

    Science.gov (United States)

    Nensa, Felix; Tezgah, E; Schweins, K; Goebel, J; Heusch, P; Nassenstein, K; Schlosser, T; Poeppel, T D

    2017-06-01

    Assessment of increased glucose uptake in inflammatory or malignant myocardial disease using PET/MRI relies on uptake suppression in normal myocardium. We evaluated the efficacy of a ≥24 hours high-fat, low-carbohydrate, and protein-permitted diet (HFLCPP) in combination with unfractionated heparin for suppression of "physiologic" myocardial glucose uptake. PET/MRI was successfully performed in 89 patients. HFLCPP was started ≥24 hours prior to PET/MRI. All patients received i.v. injection of unfractionated heparin (50 IU·kg -1 ) 15 minutes prior to FDG administration. Left ventricular FDG uptake was visually evaluated by two readers. Diffuse myocardial uptake exceeding liver uptake, isolated uptake in the lateral wall, or diffuse uptake in the entire circumference of the heart base were defined as failed suppression. Homogeneous myocardial uptake below liver uptake with/without focal uptake was defined as successful suppression. Success rate was 84%. Suppression was unsuccessful in 14 patients. No significant influence of gender (P = .40) or age (P = .21) was found. However, insufficient suppression was more common in patients younger than 45 years (20% vs 7%). PET/MR imaging completion rate was >97%. A HFLCPP diet in combination with unfractionated heparin was successfully implemented for cardiac PET/MRI and resulted in a sufficient suppression of myocardial FDG uptake in 84% of patients.

  6. Role of 18F-FDG PET/CT in the diagnosis of infective endocarditis in patients with an implanted cardiac device: a prospective study

    International Nuclear Information System (INIS)

    Graziosi, Maddalena; Lorenzini, Massimiliano; Diemberger, Igor; Pasquale, Ferdinando; Ziacchi, Matteo; Biffi, Mauro; Martignani, Cristian; Boriani, Giuseppe; Rapezzi, Claudio; Nanni, Cristina; Bonfiglioli, Rachele; Fanti, Stefano; Bartoletti, Michele; Tumietto, Fabio; Viale, Pier Luigi

    2014-01-01

    Infective endocarditis (IE) is widely underdiagnosed or diagnosed after a major delay. The diagnosis is currently based on the modified DUKE criteria, where the only validated imaging technique is echocardiography, and remains challenging especially in patients with an implantable cardiac device. The aim of this study was to assess the incremental diagnostic role of 18 F-FDG PET/CT in patients with an implanted cardiac device and suspected IE. We prospectively analysed 27 consecutive patients with an implantable device evaluated for suspected device-related IE between January 2011 and June 2013. The diagnostic probability of IE was defined at presentation according to the modified DUKE criteria. PET/CT was performed as soon as possible following the clinical suspicion of IE. Patients then underwent medical or surgical treatment based on the overall clinical evaluation. During follow-up, we considered: lead cultures in patients who underwent extraction, direct inspection and lead cultures in those who underwent surgery, and a clinical/instrumental reevaluation after at least 6 months in patients who received antimicrobial treatment or had an alternative diagnosis and were not treated for IE. After the follow-up period, the diagnosis was systematically reviewed by the multidisciplinary team using the modified DUKE criteria and considering the new findings. Among the ten patients with a positive PET/CT scan, seven received a final diagnosis of ''definite IE'', one of ''possible IE'' and two of ''IE rejected''. Among the 17 patients with a negative PET/CT scan, four were false-negative and received a final diagnosis of definite IE. These patients underwent PET/CT after having started antibiotic therapy (≥48 h) or had a technically suboptimal examination. In patients with a cardiac device, PET/CT increases the diagnostic accuracy of the modified Duke criteria for IE, particularly in the subset of patients with possible IE in whom it may help the clinician manage a

  7. Cardiac PET/CT for the diagnosis and prognostic evaluation of coronary artery disease

    International Nuclear Information System (INIS)

    Geronazzo, R.J.; Romero, R.L.; Campisi, R.

    2014-01-01

    Coronary artery disease is considered by de World Health Organization (WHO) to be pandemic. Eighty percent of the deaths occurs secondary to coronary artery disease, stroke and diabetes, thus they can be prevented. All of them are related to the same risk factors. Ischemic heart disease is the mayor cause of death in Argentina in the elderly population. Primary prevention strategies are essential in the health system. Hence, image complementary methods are very important to accomplish risk stratification, secondary prevention and pre-surgical evaluation. Nuclear cardiology has occupied this place through myocardial perfusion studies with radiopharmaceuticals, using SPECT (Single photon emission computed tomography) that have improved the level of sensitivity and specificity with ECG gated. Furthermore, positron emission tomography (PET) can evaluate relative myocardial perfusion, quantify absolute myocardial blood flow and coronary flow reserve. With its capacity to quantify rest-peak stress left ventricular systolic function we can underscore for example “balance ischemia”. By using hybrid PET/CT, also we can get information of coronary artery calcium scoring and coronary angiography. Currently, with the available softwares, we can acquire images in List mode. It means, from a single acquisition, it allows multiple image reconstructions, along with the associated electrocardiographic phase. PET/CT uses radiopharmaceuticals with short physical half life, and in conjunction with the possibility of acquiring in 3D mode, the perfusion studies can be done in a short time and offers lower radiation exposure to the patient. The new softwares for routine correction of misalignments between transmission and emission images have helped to reduce the frequency of artifacts and improve diagnostic accuracy. Hybrid PET/CT technology allows functional evaluation of myocardial perfusion combined with anatomic characterization of the epicardial coronary arteries, thereby

  8. Initial evaluation of a practical PET respiratory motion correction method in clinical simultaneous PET/MRI

    International Nuclear Information System (INIS)

    Manber, Richard; Thielemans, Kris; Hutton, Brian; Barnes, Anna; Ourselin, Sebastien; Arridge, Simon; O’Meara, Celia; Atkinson, David

    2014-01-01

    Respiratory motion during PET acquisitions can cause image artefacts, with sharpness and tracer quantification adversely affected due to count ‘smearing’. Motion correction by registration of PET gates becomes increasingly difficult with shorter scan times and less counts. The advent of simultaneous PET/MRI scanners allows the use of high spatial resolution MRI to capture motion states during respiration [1, 2]. In this work, we use a respiratory signal derived from the PET list-mode data [3, ], with no requirement for an external device or MR sequence modifications.

  9. Current status and prospects of cardiac PET

    International Nuclear Information System (INIS)

    Yoshida, Katuya

    1999-01-01

    With positron emission tomography (PET), noninvasive measurements of myocardial blood flow and metabolism have now become possible. 1) Myocardial blood flow: We developed a high-resolution PET system for rabbits and showed that myocardial N-13 ammonnia uptake correlated well with flow measure with microspheres. We also demonstrated that a simplified PET protocol using N-13 ammonia or Rb-82 provide noninvasive measurement of coronary flow reserve in dog experiments. This protocol enables to produce estimates of myocardial blood flow in man and that are well correlated with the complex compartment model. 2) Myocardial glucose metabolism: We validated experimentally a simple method to quantify tissue glucose utilization with the brain reference index (BRI) using C-14 deoxyglucose and assessed its clinical feasibility for myocardial PET. 3) Membrane integrity: Loss of cell membrane integrity for trapping the potassium or it's analog is a market of myocardial necrosis/viability. We recently synthetized potassium-38 as a PET tracer and started an experimental study. (author)

  10. Quantitative myocardial blood flow imaging with integrated time-of-flight PET-MR.

    Science.gov (United States)

    Kero, Tanja; Nordström, Jonny; Harms, Hendrik J; Sörensen, Jens; Ahlström, Håkan; Lubberink, Mark

    2017-12-01

    The use of integrated PET-MR offers new opportunities for comprehensive assessment of cardiac morphology and function. However, little is known on the quantitative accuracy of cardiac PET imaging with integrated time-of-flight PET-MR. The aim of the present work was to validate the GE Signa PET-MR scanner for quantitative cardiac PET perfusion imaging. Eleven patients (nine male; mean age 59 years; range 46-74 years) with known or suspected coronary artery disease underwent 15 O-water PET scans at rest and during adenosine-induced hyperaemia on a GE Discovery ST PET-CT and a GE Signa PET-MR scanner. PET-MR images were reconstructed using settings recommended by the manufacturer, including time-of-flight (TOF). Data were analysed semi-automatically using Cardiac VUer software, resulting in both parametric myocardial blood flow (MBF) images and segment-based MBF values. Correlation and agreement between PET-CT-based and PET-MR-based MBF values for all three coronary artery territories were assessed using regression analysis and intra-class correlation coefficients (ICC). In addition to the cardiac PET-MR reconstruction protocol as recommended by the manufacturer, comparisons were made using a PET-CT resolution-matched reconstruction protocol both without and with TOF to assess the effect of time-of-flight and reconstruction parameters on quantitative MBF values. Stress MBF data from one patient was excluded due to movement during the PET-CT scanning. Mean MBF values at rest and stress were (0.92 ± 0.12) and (2.74 ± 1.37) mL/g/min for PET-CT and (0.90 ± 0.23) and (2.65 ± 1.15) mL/g/min for PET-MR (p = 0.33 and p = 0.74). ICC between PET-CT-based and PET-MR-based regional MBF was 0.98. Image quality was improved with PET-MR as compared to PET-CT. ICC between PET-MR-based regional MBF with and without TOF and using different filter and reconstruction settings was 1.00. PET-MR-based MBF values correlated well with PET-CT-based MBF values and

  11. A Case of Low-Grade Primary Cardiac Lymphoma with Pericardial Effusion Diagnosed by Combined 18F-Fluorodeoxyglucose Positron Emission Tomography and Computed Tomography (FDG-PET/CT) Imaging and Effusion Cytology.

    Science.gov (United States)

    Fukunaga, Hisanori; Tatewaki, Yasuko; Mutoh, Tatsushi; Shimomura, Hideo; Yamamoto, Shuzo; Terao, Chiaki; Totsune, Tomoko; Nakagawa, Manabu; Taki, Yasuyuki

    2018-03-14

    BACKGROUND Primary cardiac lymphoma is rare and can be an aggressive disease, depending on the grade. A case is reported of low-grade primary cardiac lymphoma associated with a pericardial effusion. 18F-fluorodeoxyglucose positron emission tomography and computed tomography (FDG-PET/CT) imaging was useful in the diagnosis and in evaluating the disease activity in this case. CASE REPORT A 72-year-old Japanese woman visited a general practitioner, complaining of dyspnea associated with cardiac tamponade. Pericardiocentesis was performed, and Group V malignant cells were identified by cytology, suspicious for malignant lymphoma. Whole-body FDG-PET/CT scans showed no pleural effusion or lymph node metastasis supporting the diagnosis of primary cardiac lymphoma diagnosed on pericardial effusion. The laboratory investigations showed that levels of serum soluble interleukin-2 (IL-2) receptor (sIL-2R), a diagnostic and prognostic marker for malignant lymphoma, were not elevated (258 U/ml). A six-month follow-up FDG-PET/CT scan showed an increased volume of the pericardial effusion and mild but abnormal uptake diffusely in the pericardial space, and the sIL-2R was slightly elevated (860 U/ml). No abnormal FDG accumulation outside the retained pericardial effusion was noted, which was compatible with a clinical picture of low-grade primary cardiac lymphoma, and in a period of watchful waiting during the first two years later, the sIL-2R had reduced to 195 U/ml. CONCLUSIONS This is a rare case of low-grade primary cardiac lymphoma detected in a pericardial effusion, and highlights the utility of the FDG-PET/CT scan as a valuable diagnostic and follow-up modality.

  12. Voltage-Gated Sodium Channel β1/β1B Subunits Regulate Cardiac Physiology and Pathophysiology

    Directory of Open Access Journals (Sweden)

    Nnamdi Edokobi

    2018-04-01

    Full Text Available Cardiac myocyte contraction is initiated by a set of intricately orchestrated electrical impulses, collectively known as action potentials (APs. Voltage-gated sodium channels (NaVs are responsible for the upstroke and propagation of APs in excitable cells, including cardiomyocytes. NaVs consist of a single, pore-forming α subunit and two different β subunits. The β subunits are multifunctional cell adhesion molecules and channel modulators that have cell type and subcellular domain specific functional effects. Variants in SCN1B, the gene encoding the Nav-β1 and -β1B subunits, are linked to atrial and ventricular arrhythmias, e.g., Brugada syndrome, as well as to the early infantile epileptic encephalopathy Dravet syndrome, all of which put patients at risk for sudden death. Evidence over the past two decades has demonstrated that Nav-β1/β1B subunits play critical roles in cardiac myocyte physiology, in which they regulate tetrodotoxin-resistant and -sensitive sodium currents, potassium currents, and calcium handling, and that Nav-β1/β1B subunit dysfunction generates substrates for arrhythmias. This review will highlight the role of Nav-β1/β1B subunits in cardiac physiology and pathophysiology.

  13. Symptomatic cardiac toxicity is predicted by dosimetric and patient factors rather than changes in 18F-FDG PET determination of myocardial activity after chemoradiotherapy for esophageal cancer

    International Nuclear Information System (INIS)

    Konski, Andre; Li Tianyu; Christensen, Michael; Cheng, Jonathan D.; Yu, Jian Q.; Crawford, Kevin; Haluszka, Oleh; Tokar, Jeffrey; Scott, Walter; Meropol, Neal J.; Cohen, Steven J.; Maurer, Alan; Freedman, Gary M.

    2012-01-01

    Purpose: To determine factors associated with symptomatic cardiac toxicity in patients with esophageal cancer treated with chemoradiotherapy. Material and methods: We retrospectively evaluated 102 patients treated with chemoradiotherapy for locally advanced esophageal cancer. Our primary endpoint was symptomatic cardiac toxicity. Radiation dosimetry, patient demographic factors, and myocardial changes seen on 18 F-FDG PET were correlated with subsequent cardiac toxicity. Cardiac toxicity measured by RTOG and CTCAE v3.0 criteria was identified by chart review. Results: During the follow up period, 12 patients were identified with treatment related cardiac toxicity, 6 of which were symptomatic. The mean heart V20 (79.7% vs. 67.2%, p = 0.05), V30 (75.8% vs. 61.9%, p = 0.04), and V40 (69.2% vs. 53.8%, p = 0.03) were significantly higher in patients with symptomatic cardiac toxicity than those without. We found the threshold for symptomatic cardiac toxicity to be a V20, V30 and V40 above 70%, 65% and 60%, respectively. There was no correlation between change myocardial SUV on PET and cardiac toxicity, however, a greater proportion of women suffered symptomatic cardiac toxicity compared to men (p = 0.005). Conclusions: A correlation did not exist between percent change in myocardial SUV and cardiac toxicity. Patients with symptomatic cardiac toxicity received significantly greater mean V20, 30 and 40 values to the heart compared to asymptomatic patients. These data need validation in a larger independent data set.

  14. Role of {sup 18}F-FDG PET/CT in the diagnosis of infective endocarditis in patients with an implanted cardiac device: a prospective study

    Energy Technology Data Exchange (ETDEWEB)

    Graziosi, Maddalena; Lorenzini, Massimiliano; Diemberger, Igor; Pasquale, Ferdinando; Ziacchi, Matteo; Biffi, Mauro; Martignani, Cristian; Boriani, Giuseppe; Rapezzi, Claudio [Alma Mater-University of Bologna, and S. Orsola-Malpighi Hospital, Cardiology Unit, Department of Experimental, Diagnostic and Specialty Medicine, Bologna (Italy); Nanni, Cristina; Bonfiglioli, Rachele; Fanti, Stefano [Alma Mater-University of Bologna, and S. Orsola-Malpighi Hospital, Nuclear Medicine Unit, Department of Experimental, Diagnostic and Specialty Medicine, Bologna (Italy); Bartoletti, Michele; Tumietto, Fabio; Viale, Pier Luigi [Alma Mater-University of Bologna, and S. Orsola-Malpighi Hospital, Infectious Diseases Unit, Department of Medical and Surgical Sciences, Bologna (Italy)

    2014-08-15

    Infective endocarditis (IE) is widely underdiagnosed or diagnosed after a major delay. The diagnosis is currently based on the modified DUKE criteria, where the only validated imaging technique is echocardiography, and remains challenging especially in patients with an implantable cardiac device. The aim of this study was to assess the incremental diagnostic role of {sup 18}F-FDG PET/CT in patients with an implanted cardiac device and suspected IE. We prospectively analysed 27 consecutive patients with an implantable device evaluated for suspected device-related IE between January 2011 and June 2013. The diagnostic probability of IE was defined at presentation according to the modified DUKE criteria. PET/CT was performed as soon as possible following the clinical suspicion of IE. Patients then underwent medical or surgical treatment based on the overall clinical evaluation. During follow-up, we considered: lead cultures in patients who underwent extraction, direct inspection and lead cultures in those who underwent surgery, and a clinical/instrumental reevaluation after at least 6 months in patients who received antimicrobial treatment or had an alternative diagnosis and were not treated for IE. After the follow-up period, the diagnosis was systematically reviewed by the multidisciplinary team using the modified DUKE criteria and considering the new findings. Among the ten patients with a positive PET/CT scan, seven received a final diagnosis of ''definite IE'', one of ''possible IE'' and two of ''IE rejected''. Among the 17 patients with a negative PET/CT scan, four were false-negative and received a final diagnosis of definite IE. These patients underwent PET/CT after having started antibiotic therapy (≥48 h) or had a technically suboptimal examination. In patients with a cardiac device, PET/CT increases the diagnostic accuracy of the modified Duke criteria for IE, particularly in the subset of

  15. A knowledge-based method for reducing attenuation artefacts caused by cardiac appliances in myocardial PET/CT

    Energy Technology Data Exchange (ETDEWEB)

    Hamill, James J [Siemens Medical Solutions, Molecular Imaging, 810 Innovation Dr., Knoxville, TN (United States); Brunken, Richard C [Department of Molecular and Functional Imaging, Cleveland Clinic Foundation, 9500 Euclid Ave., Cleveland, OH (United States); Bybel, Bohdan [Department of Molecular and Functional Imaging, Cleveland Clinic Foundation, 9500 Euclid Ave., Cleveland, OH (United States); DiFilippo, Frank P [Department of Molecular and Functional Imaging, Cleveland Clinic Foundation, 9500 Euclid Ave., Cleveland, OH (United States); Faul, David D [Siemens Medical Solutions, Molecular Imaging, 810 Innovation Dr., Knoxville, TN (United States)

    2006-06-07

    Attenuation artefacts due to implanted cardiac defibrillator leads have previously been shown to adversely impact cardiac PET/CT imaging. In this study, the severity of the problem is characterized, and an image-based method is described which reduces the resulting artefact in PET. Automatic implantable cardioverter defibrillator (AICD) leads cause a moving-metal artefact in the CT sections from which the PET attenuation correction factors (ACFs) are derived. Fluoroscopic cine images were measured to demonstrate that the defibrillator's highly attenuating distal shocking coil moves rhythmically across distances on the order of 1 cm. Rhythmic motion of this magnitude was created in a phantom with a moving defibrillator lead. A CT study of the phantom showed that the artefact contained regions of incorrect, very high CT values and adjacent regions of incorrect, very low CT values. The study also showed that motion made the artefact more severe. A knowledge-based metal artefact reduction method (MAR) is described that reduces the magnitude of the error in the CT images, without use of the corrupted sinograms. The method modifies the corrupted image through a sequence of artefact detection procedures, morphological operations, adjustments of CT values and three-dimensional filtering. The method treats bone the same as metal. The artefact reduction method is shown to run in a few seconds, and is validated by applying it to a series of phantom studies in which reconstructed PET tracer distribution values are wrong by as much as 60% in regions near the CT artefact when MAR is not applied, but the errors are reduced to about 10% of expected values when MAR is applied. MAR changes PET image values by a few per cent in regions not close to the artefact. The changes can be larger in the vicinity of bone. In patient studies, the PET reconstruction without MAR sometimes results in anomalously high values in the infero-septal wall. Clinical performance of MAR is assessed by

  16. Cardiac cone-beam CT

    International Nuclear Information System (INIS)

    Manzke, Robert

    2005-01-01

    This doctoral thesis addresses imaging of the heart with retrospectively gated helical cone-beam computed tomography (CT). A thorough review of the CT reconstruction literature is presented in combination with a historic overview of cardiac CT imaging and a brief introduction to other cardiac imaging modalities. The thesis includes a comprehensive chapter about the theory of CT reconstruction, familiarizing the reader with the problem of cone-beam reconstruction. The anatomic and dynamic properties of the heart are outlined and techniques to derive the gating information are reviewed. With the extended cardiac reconstruction (ECR) framework, a new approach is presented for the heart-rate-adaptive gated helical cardiac cone-beam CT reconstruction. Reconstruction assessment criteria such as the temporal resolution, the homogeneity in terms of the cardiac phase, and the smoothness at cycle-to-cycle transitions are developed. Several reconstruction optimization approaches are described: An approach for the heart-rate-adaptive optimization of the temporal resolution is presented. Streak artifacts at cycle-to-cycle transitions can be minimized by using an improved cardiac weighting scheme. The optimal quiescent cardiac phase for the reconstruction can be determined automatically with the motion map technique. Results for all optimization procedures applied to ECR are presented and discussed based on patient and phantom data. The ECR algorithm is analyzed for larger detector arrays of future cone-beam systems throughout an extensive simulation study based on a four-dimensional cardiac CT phantom. The results of the scientific work are summarized and an outlook proposing future directions is given. The presented thesis is available for public download at www.cardiac-ct.net

  17. Free breathing whole-heart 3D CINE MRI with self-gated Cartesian trajectory.

    Science.gov (United States)

    Usman, M; Ruijsink, B; Nazir, M S; Cruz, G; Prieto, C

    2017-05-01

    To present a method that uses a novel free-running self-gated acquisition to achieve isotropic resolution in whole heart 3D Cartesian cardiac CINE MRI. 3D cardiac CINE MRI using navigator gating results in long acquisition times. Recently, several frameworks based on self-gated non-Cartesian trajectories have been proposed to accelerate this acquisition. However, non-Cartesian reconstructions are computationally expensive due to gridding, particularly in 3D. In this work, we propose a novel highly efficient self-gated Cartesian approach for 3D cardiac CINE MRI. Acquisition is performed using CArtesian trajectory with Spiral PRofile ordering and Tiny golden angle step for eddy current reduction (so called here CASPR-Tiger). Data is acquired continuously under free breathing (retrospective ECG gating, no preparation pulses interruption) for 4-5min and 4D whole-heart volumes (3D+cardiac phases) with isotropic spatial resolution are reconstructed from all available data using a soft gating technique combined with temporal total variation (TV) constrained iterative SENSE reconstruction. For data acquired on eight healthy subjects and three patients, the reconstructed images using the proposed method had good contrast and spatio-temporal variations, correctly recovering diastolic and systolic cardiac phases. Non-significant differences (P>0.05) were observed in cardiac functional measurements obtained with proposed 3D approach and gold standard 2D multi-slice breath-hold acquisition. The proposed approach enables isotropic 3D whole heart Cartesian cardiac CINE MRI in 4 to 5min free breathing acquisition. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  18. Utility of QGS for 201Tl electrocardiogram-gated SPECT in cardiac function evaluations

    International Nuclear Information System (INIS)

    Shimazaki, Hiroshi; Oono, Ryuichi

    2001-01-01

    QGS (quantitative gated SPECT) was applied to 201 Tl SPECT, whose images are inferior to those of Tc SPECT, and its utility was evaluated. More specifically, the cardiac function index was calculated by QGS, and local wall motion was evaluated visually. Accuracy was assessed by comparison with left ventriculography. The subjects were 29 patients (21 males, 8 females; 6 with myocardial infarction, 18 with stenocardia, 2 with pericardial disease, 3 with other heart diseases) who had undergone myocardial scintigraphy and left ventriculography between February and May, 2000. 201 Tl (74 or 111 MBq) was administered to all patients. The resting image was obtained 10 minutes later, and the delayed image during loading was obtained 4 hours later. The conditions for acquiring the images were as follows. Two detectors were arranged at a 90-degree angle in the form of an L. The 180 degrees from 45 degrees right anterior oblique (RAO) to 45 degrees left posterior oblique (LPO) were divided into 30 sections at 6-degree intervals, and the image in each section was acquired for 60 seconds. The matrix was 64 x 64. As a cardiac function index, the left ventricular ejection function (LVEF) obtained by electrocardiogram-gated SPECT (QGS-EF) at the rest (14 cases) and the QGS-EF on the delayed images (15 cases) were compared with the LVEF determined by left ventriculography (LVG-EF). There was an excellent positive correlation between the data obtained by two methods, with a correlation coefficient of r=0.93 (y=1.04x-0.04). Most of the difference between the values fell within two standard deviations, and the error was in the clinically allowable range. There was no significant difference between the correlation coefficient at rest and during loading or between the cases that showed an obvious defect on the image and those that did not. The local wall motion of the left ventricle was visually evaluated in five stages in two directions (RAO, 30 degrees, and LAO, 60 degrees). The motion

  19. Evaluation of an exposed-radiation dose on a dual-source cardiac computed tomography examination with a prospective electrocardiogram-gated fast dual spiral scan

    International Nuclear Information System (INIS)

    Matsubara, Kosuke; Koshida, Kichiro; Koshida, Haruka; Sakuta, Keita; Hayashi, Hiroyuki; Takata, Tadanori; Horii, Junsei; Kawai, Keiichi; Yamamoto, Tomoyuki

    2012-01-01

    We evaluated exposed-radiation doses on dual-source cardiac computed tomography (CT) examinations with prospective electrocardiogram (ECG)-gated fast dual spiral scans. After placing dosimeters at locations corresponding to each of the thoracic organs, prospective ECG-gated fast dual spirals and retrospective ECG-gated dual spiral scans were performed to measure the absorbed dose of each organ. In the prospective ECG-gated fast dual spiral scans, the average absorbed doses were 5.03 mGy for the breast, 9.96 mGy for the heart, 6.60 mGy for the lung, 6.48 mGy for the bone marrow, 9.73 mGy for the thymus, and 4.58 mGy for the skin. These values were about 5% of the absorbed doses for the retrospective ECG-gated dual spiral scan. However, the absorbed dose differed greatly at each scan, especially in the external organs such as the breast. For effective and safe use of the prospective ECG-gated fast dual spiral scan, it is necessary to understand these characteristics sufficiently. (author)

  20. Greater adenosine A2A receptor densities in cardiac and skeletal muscle in endurance-trained men: a [11C]TMSX PET study

    International Nuclear Information System (INIS)

    Mizuno, Masaki; Kimura, Yuichi; Tokizawa, Ken; Ishii, Kenji; Oda, Keiichi; Sasaki, Toru; Nakamura, Yoshio; Muraoka, Isao; Ishiwata, Kiichi

    2005-01-01

    We examined the densities of adenosine A 2A receptors in cardiac and skeletal muscles between untrained and endurance-trained subjects using positron emission tomography (PET) and [7-methyl- 11 C]-(E)-8-(3,4,5-trimethoxystyryl)-1,3,7-trimethylxanthine ([ 11 C]TMSX), a newly developed radioligand for mapping adenosine A 2A receptors. Five untrained and five endurance-trained subjects participated in this study. The density of adenosine A 2A receptors was evaluated as the distribution volume of [ 11 C]TMSX in cardiac and triceps brachii muscles in the resting state using PET. The distribution volume of [ 11 C]TMSX in the myocardium was significantly greater than in the triceps brachii muscle in both groups. Further, distribution volumes [ 11 C]TMSX in the trained subjects were significantly grater than those in untrained subjects (myocardium, 3.6±0.3 vs. 3.1±0.4 ml g -1 ; triceps brachii muscle, 1.7±0.3 vs. 1.2±0.2 ml g -1 , respectively). These results indicate that the densities of adenosine A 2A receptors in the cardiac and skeletal muscles are greater in the endurance-trained men than in the untrained men

  1. High-resolution imaging of pulmonary ventilation and perfusion with {sup 68}Ga-VQ respiratory gated (4-D) PET/CT

    Energy Technology Data Exchange (ETDEWEB)

    Callahan, Jason [Centre for Molecular Imaging, Peter MacCallum Cancer Centre, East Melbourne, VIC (Australia); Hofman, Michael S. [The University of Melbourne, Department of Medicine, Peter MacCallum Cancer Centre, Centre for Molecular Imaging, East Melbourne, VIC (Australia); Siva, Shankar [The University of Melbourne, Peter MacCallum Cancer Centre, Department of Radiation Oncology, East Melbourne, VIC (Australia); The University of Melbourne, Sir Peter MacCallum Department of Oncology, East Melbourne, VIC (Australia); Kron, Tomas [The University of Melbourne, Sir Peter MacCallum Department of Oncology, East Melbourne, VIC (Australia); The University of Melbourne, Peter MacCallum Cancer Centre, Department of Physical Sciences, East Melbourne, VIC (Australia); Schneider, Michal E. [Monash University, Department of Medical Imaging and Radiation Science, Clayton, VIC (Australia); Binns, David; Eu, Peter [Peter MacCallum Cancer Centre, Centre for Cancer Imaging, East Melbourne, VIC (Australia); Hicks, Rodney J. [The University of Melbourne, Sir Peter MacCallum Department of Oncology, Peter MacCallum Cancer Centre, Centre for Molecular Imaging, East Melbourne, VIC (Australia)

    2014-02-15

    Our group has previously reported on the use of {sup 68}Ga-ventilation/perfusion (VQ) PET/CT scanning for the diagnosis of pulmonary embolism. We describe here the acquisition methodology for {sup 68}Ga-VQ respiratory gated (4-D) PET/CT and the effects of respiratory motion on image coregistration in VQ scanning. A prospective study was performed in 15 patients with non-small-cell lung cancer. 4-D PET and 4-D CT images were acquired using an infrared marker on the patient's abdomen as a surrogate for breathing motion following inhalation of Galligas and intravenous administration of {sup 68}Ga-macroaggregated albumin. Images were reconstructed with phase-matched attenuation correction. The lungs were contoured on CT and PET VQ images during free-breathing (FB) and at maximum inspiration (Insp) and expiration (Exp). The similarity between PET and CT volumes was measured using the Dice coefficient (DC) comparing the following groups; (1) FB-PET/CT, (2) InspPET/InspCT, (3) ExpPET/Exp CT, and (4) FB-PET/AveCT. A repeated measures one-way ANOVA with multiple comparison Tukey tests were performed to evaluate any difference between the groups. Diaphragmatic motion in the superior-inferior direction on the 4-D CT scan was also measured. 4-D VQ scanning was successful in all patients without additional acquisition time compared to the nongated technique. The highest volume overlap was between ExpPET and ExpCT and between FB-PET and AveCT with a DC of 0.82 and 0.80 for ventilation and perfusion, respectively. This was significantly better than the DC comparing the other groups (0.78-0.79, p < 0.05). These values agreed with a visual inspection of the images with improved image coregistration around the lung bases. The diaphragmatic motion during the 4-D CT scan was highly variable with a range of 0.4-3.4 cm (SD 0.81 cm) in the right lung and 0-2.8 cm (SD 0.83 cm) in the left lung. Right-sided diaphragmatic nerve palsy was observed in 3 of 15 patients. {sup 68}Ga-VQ 4-D

  2. 18F-FDG-PET/CT angiography in the diagnosis of infective endocarditis and cardiac device infection in adult patients with congenital heart disease and prosthetic material.

    Science.gov (United States)

    Pizzi, María N; Dos-Subirà, L; Roque, Albert; Fernández-Hidalgo, Nuria; Cuéllar-Calabria, Hug; Pijuan Domènech, Antonia; Gonzàlez-Alujas, María T; Subirana-Domènech, M T; Miranda-Barrio, B; Ferreira-González, Ignacio; González-López, Juan J; Igual, Albert; Maisterra-Santos, Olga; García-Dorado, David; Castell-Conesa, Joan; Almirante, Benito; Escobar Amores, Manuel; Tornos, Pilar; Aguadé-Bruix, Santiago

    2017-12-01

    Infective endocarditis (IE) and cardiac device infection (CDI) are a major complication in the growing number of patients with congenital heart disease (CHD) reaching adulthood. We aimed to evaluate the added value of 18 F-FDG-PET/CT angiography (PET/CTA) in the diagnosis of IE-CDI in adults with CHD and intravascular or intracardiac prosthetic material, in whom echocardiography (ECHO) and modified Duke Criteria (DC) have limitations because of the patients' complex anatomy. A prospective study was conducted in a referral center with multidisciplinary IE and CHD Units. PET/CTA and ECHO findings were compared in consecutive adult (≥18years) patients with CHD who have prosthetic material and suspected IE-CDI. The initial diagnosis using the DC and the diagnosis with the additional PET/CTA data (DC+PET/CTA) were compared with the final diagnostic consensus established by an expert team at three months. Between November-2012 and April-2017, 25 patients (15 men; median age 40years) were included. Cases were initially classified as definite in 8 (32%), possible in 14 (56%) and rejected in 3 (12%). DC+PET/CTA allowed reclassification of 12/14 (86%) cases initially identified as possible IE. The sensitivity, specificity, PPV, NPV, and accuracy of DC at IE suspicion were 39.1%/83.3%/90.4%/25.5%/61.2%, respectively. The diagnostic performance increased significantly with addition of PET/CTA data: 87%/83.3%/95.4%/61.5%/85.1%, respectively. PET/CTA also provided an alternative diagnosis in 3 patients with rejected IE, and detected pulmonary embolisms in 3 patients. PET/CTA was a useful diagnostic tool in the complex group of adult patients with CHD who have cardiac or intravascular prosthetic material and suspected IE or CDI, providing added diagnostic value to the modified DC (increased sensitivity) and improving case classification. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

  3. Churg-Strauss syndrome cardiac involvement evaluated by cardiac magnetic resonance imaging and positron-emission tomography: a prospective study on 20 patients

    International Nuclear Information System (INIS)

    Marmursztejn, Julien; Guillevin, Loic; Cohen, Pascal; Guilpain, Philippe; Pagnoux, Christian; Mouthon, Luc; Trebossen, Regine; Legmann, Paul; Vignaux, Olivier; Duboc, Denis

    2013-01-01

    Churg-Strauss syndrome (CSS) cardiac involvement is associated with a poor prognosis. Recently cardiac MRI (CMRI) has emerged as a promising technique to detect early CSS cardiac involvement. However, CMRI-detected myocardial delayed enhancement (MDE) could correspond to fibrosis or inflammation. Fluoro-2-deoxyglucose PET (FDG-PET) was previously used in other systemic diseases to distinguish between them. To determine whether the CMRI-MDE detected in CSS patients reflected fibrosis or myocardial inflammation, patients in CSS remission underwent FDG-PET. Twenty consecutive CSS patients in remission (BVAS = 0) were recruited. Fourteen patients [eight men, six women; mean (S.D.) age 49 (9) years; mean disease duration 3.5 (2.9) years] with CMRI-detected MDE, and six patients [four men, two women; mean (S.D.) age 44 (15) years; mean disease duration 3.5 (5.3) years] with normal CMRI underwent FDG-PET. Segments with MDE on CMRI were analysed on FDG-PET images, with myocardial FDG hypo-fixation defining fibrosis and hyper-fixation corresponding inflammation. Among the 14 patients with MDE on CMRI, FDG-PET showed 10 had hypo-fixation, 2 had hyper-fixation and 2 had normal scans. CSS duration at the time of CMRI was shorter for patients with myocardial inflammation than in those with fibrosis. The six patients with normal CMRI had normal FDG-PET images. For CSS patients in remission, CMRI detected subclinical active myocardial lesions and could be recommended to assess cardiac involvement. However, because CMRI-detected MDE can reflect fibrosis or inflammation, FDG-PET might help to distinguish between the two. (authors)

  4. Churg-Strauss syndrome cardiac involvement evaluated by cardiac magnetic resonance imaging and positron-emission tomography: a prospective study on 20 patients

    Energy Technology Data Exchange (ETDEWEB)

    Marmursztejn, Julien [Department of Cardiology, Service Frederic Joliot CEA Orsay, Hopital Cochin, AP-HP, Universite Paris Descartes, Sorbonne Paris Cite, Paris, (France); Department of Radiology, Service Frederic Joliot CEA Orsay, Hopital Cochin, AP-HP, Universite Paris Descartes, Sorbonne Paris Cite, Paris, (France); Guillevin, Loic; Cohen, Pascal; Guilpain, Philippe; Pagnoux, Christian; Mouthon, Luc [Department of Internal Medicine, Service Frederic Joliot CEA Orsay, Hopital Cochin, AP-HP, Universite Paris Descartes, Sorbonne Paris Cite, Paris, (France); Trebossen, Regine [Department of Nuclear Medicine, Service Frederic Joliot CEA Orsay, Hopital Cochin, AP-HP, Universite Paris Descartes, Sorbonne Paris Cite, Paris, (France); Legmann, Paul; Vignaux, Olivier [Department of Radiology, Service Frederic Joliot CEA Orsay, Hopital Cochin, AP-HP, Universite Paris Descartes, Sorbonne Paris Cite, Paris, (France); Duboc, Denis [Department of Cardiology, Service Frederic Joliot CEA Orsay, Hopital Cochin, AP-HP, Universite Paris Descartes, Sorbonne Paris Cite, Paris, (France)

    2013-07-01

    Churg-Strauss syndrome (CSS) cardiac involvement is associated with a poor prognosis. Recently cardiac MRI (CMRI) has emerged as a promising technique to detect early CSS cardiac involvement. However, CMRI-detected myocardial delayed enhancement (MDE) could correspond to fibrosis or inflammation. Fluoro-2-deoxyglucose PET (FDG-PET) was previously used in other systemic diseases to distinguish between them. To determine whether the CMRI-MDE detected in CSS patients reflected fibrosis or myocardial inflammation, patients in CSS remission underwent FDG-PET. Twenty consecutive CSS patients in remission (BVAS = 0) were recruited. Fourteen patients [eight men, six women; mean (S.D.) age 49 (9) years; mean disease duration 3.5 (2.9) years] with CMRI-detected MDE, and six patients [four men, two women; mean (S.D.) age 44 (15) years; mean disease duration 3.5 (5.3) years] with normal CMRI underwent FDG-PET. Segments with MDE on CMRI were analysed on FDG-PET images, with myocardial FDG hypo-fixation defining fibrosis and hyper-fixation corresponding inflammation. Among the 14 patients with MDE on CMRI, FDG-PET showed 10 had hypo-fixation, 2 had hyper-fixation and 2 had normal scans. CSS duration at the time of CMRI was shorter for patients with myocardial inflammation than in those with fibrosis. The six patients with normal CMRI had normal FDG-PET images. For CSS patients in remission, CMRI detected subclinical active myocardial lesions and could be recommended to assess cardiac involvement. However, because CMRI-detected MDE can reflect fibrosis or inflammation, FDG-PET might help to distinguish between the two. (authors)

  5. GATE: Improving the computational efficiency

    International Nuclear Information System (INIS)

    Staelens, S.; De Beenhouwer, J.; Kruecker, D.; Maigne, L.; Rannou, F.; Ferrer, L.; D'Asseler, Y.; Buvat, I.; Lemahieu, I.

    2006-01-01

    GATE is a software dedicated to Monte Carlo simulations in Single Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET). An important disadvantage of those simulations is the fundamental burden of computation time. This manuscript describes three different techniques in order to improve the efficiency of those simulations. Firstly, the implementation of variance reduction techniques (VRTs), more specifically the incorporation of geometrical importance sampling, is discussed. After this, the newly designed cluster version of the GATE software is described. The experiments have shown that GATE simulations scale very well on a cluster of homogeneous computers. Finally, an elaboration on the deployment of GATE on the Enabling Grids for E-Science in Europe (EGEE) grid will conclude the description of efficiency enhancement efforts. The three aforementioned methods improve the efficiency of GATE to a large extent and make realistic patient-specific overnight Monte Carlo simulations achievable

  6. Feasibility of Systematic Respiratory-Gated Acquisition in Unselected Patients Referred for 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography

    Directory of Open Access Journals (Sweden)

    Philippe Robin

    2018-02-01

    Full Text Available ObjectiveRespiratory motion in 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT induces blurred images, leading to errors in location and quantification for lung and abdominal lesions. Various methods have been developed to correct for these artifacts, and most of current PET/CT scanners are equipped with a respiratory gating system. However, they are not routinely performed because their use is time-consuming. The aim of this study is to assess the feasibility and quantitative impact of a systematic respiratory-gated acquisition in unselected patients referred for FDG PET/CT, without increasing acquisition time.MethodsPatients referred for a FDG PET/CT examination to the nuclear medicine department of Brest University Hospital were consecutively enrolled, during a 3-month period. Cases presenting lung or liver uptakes were analyzed. Two sets of images were reconstructed from data recorded during a unique acquisition with a continuous table speed of 1 mm/s of the used Biograph mCT Flow PET/CT scanner: standard free-breathing images, and respiratory-gated images. Lesion location and quantitative parameters were recorded and compared.ResultsFrom October 1 2015 to December 31 2015, 847 patients were referred for FDG PET/CT, 741 underwent a respiratory-gated acquisition. Out of them, 213 (29% had one or more lung or liver uptake but 82 (38% had no usable respiratory-gated signal. Accordingly, 131 (62% patients with 183 lung or liver uptakes were analyzed. Considering the 183 lesions, 140 and 43 were located in the lungs and the liver, respectively. The median (IQR difference between respiratory-gated images and non-gated images was 18% (4−32 for SUVmax, increasing to 30% (14−57 in lower lobes for lung lesions, and −18% (−40 to −4 for MTV (p < 0.05. Technologists’ active personal dosimetry and mean total examinations duration were not statistically different between periods with and without

  7. Current status and future perspective of PET

    International Nuclear Information System (INIS)

    Lee, Myung Chul

    2002-01-01

    ,015 and 4,414 in 1996, 1997, 1998, 1999 and 2000, respectively. The application in cardiac disorders is minimal, and among various neuropsychiatric diseases, patients with epilepsy or dementia can benefit from PET studies. Recently, we investigated brain mapping and neuroreceptor works. PET is not a key application for evaluation of the cardiac patients in Korea because of the relatively low incidence of cardiac disease and less costly procedures such as SPECT can now be performed

  8. Direct reconstruction of cardiac PET kinetic parametric images using a preconditioned conjugate gradient approach.

    Science.gov (United States)

    Rakvongthai, Yothin; Ouyang, Jinsong; Guerin, Bastien; Li, Quanzheng; Alpert, Nathaniel M; El Fakhri, Georges

    2013-10-01

    Our research goal is to develop an algorithm to reconstruct cardiac positron emission tomography (PET) kinetic parametric images directly from sinograms and compare its performance with the conventional indirect approach. Time activity curves of a NCAT phantom were computed according to a one-tissue compartmental kinetic model with realistic kinetic parameters. The sinograms at each time frame were simulated using the activity distribution for the time frame. The authors reconstructed the parametric images directly from the sinograms by optimizing a cost function, which included the Poisson log-likelihood and a spatial regularization terms, using the preconditioned conjugate gradient (PCG) algorithm with the proposed preconditioner. The proposed preconditioner is a diagonal matrix whose diagonal entries are the ratio of the parameter and the sensitivity of the radioactivity associated with parameter. The authors compared the reconstructed parametric images using the direct approach with those reconstructed using the conventional indirect approach. At the same bias, the direct approach yielded significant relative reduction in standard deviation by 12%-29% and 32%-70% for 50 × 10(6) and 10 × 10(6) detected coincidences counts, respectively. Also, the PCG method effectively reached a constant value after only 10 iterations (with numerical convergence achieved after 40-50 iterations), while more than 500 iterations were needed for CG. The authors have developed a novel approach based on the PCG algorithm to directly reconstruct cardiac PET parametric images from sinograms, and yield better estimation of kinetic parameters than the conventional indirect approach, i.e., curve fitting of reconstructed images. The PCG method increases the convergence rate of reconstruction significantly as compared to the conventional CG method.

  9. The Impact of Optimal Respiratory Gating and Image Noise on Evaluation of Intratumor Heterogeneity on 18F-FDG PET Imaging of Lung Cancer.

    Science.gov (United States)

    Grootjans, Willem; Tixier, Florent; van der Vos, Charlotte S; Vriens, Dennis; Le Rest, Catherine C; Bussink, Johan; Oyen, Wim J G; de Geus-Oei, Lioe-Fee; Visvikis, Dimitris; Visser, Eric P

    2016-11-01

    Accurate measurement of intratumor heterogeneity using parameters of texture on PET images is essential for precise characterization of cancer lesions. In this study, we investigated the influence of respiratory motion and varying noise levels on quantification of textural parameters in patients with lung cancer. We used an optimal-respiratory-gating algorithm on the list-mode data of 60 lung cancer patients who underwent 18 F-FDG PET. The images were reconstructed using a duty cycle of 35% (percentage of the total acquired PET data). In addition, nongated images of varying statistical quality (using 35% and 100% of the PET data) were reconstructed to investigate the effects of image noise. Several global image-derived indices and textural parameters (entropy, high-intensity emphasis, zone percentage, and dissimilarity) that have been associated with patient outcome were calculated. The clinical impact of optimal respiratory gating and image noise on assessment of intratumor heterogeneity was evaluated using Cox regression models, with overall survival as the outcome measure. The threshold for statistical significance was adjusted for multiple comparisons using Bonferroni correction. In the lower lung lobes, respiratory motion significantly affected quantification of intratumor heterogeneity for all textural parameters (P 0.007). The mean increase in entropy, dissimilarity, zone percentage, and high-intensity emphasis was 1.3% ± 1.5% (P = 0.02), 11.6% ± 11.8% (P = 0.006), 2.3% ± 2.2% (P = 0.002), and 16.8% ± 17.2% (P = 0.006), respectively. No significant differences were observed for lesions in the upper lung lobes (P > 0.007). Differences in the statistical quality of the PET images affected the textural parameters less than respiratory motion, with no significant difference observed. The median follow-up time was 35 mo (range, 7-39 mo). In multivariate analysis for overall survival, total lesion glycolysis and high-intensity emphasis were the two most

  10. Clinical application of ECG-gated 256-slice CT angiography for diagnosis of congenital heart disease

    International Nuclear Information System (INIS)

    Tian Xinhua; Liu Jianhua; Gong Tingting; Geng Lili; Sun Yong

    2011-01-01

    Objective: To investigate the clinical application of ECG-gated 256-slice CT angiography for diagnosis of congenital heart disease, and to evaluate the relationship of the image quality and radiation dose between prospective ECG-gated and retrospective ECG-gated cardiac CT angiography (CTA). Methods: Sixty patients who doubt congenital heart disease underwent cardiac CTA, and they were randomly divided into two groups. Thirty patients in group A underwent prospective ECG-gated cardiac CTA, and thirty patients in group B underwent retrospective ECG-gated cardiac CTA. Then the homogeneous enhancement of vascular structures, stair-step artifact, overall image quality and radiation dose were evaluated. Results: The homogeneous enhancement of vascular structures were 2.8±0.3 and 2.7±0.6, respectively, in two groups; and there was no statistical significance (P>0.05). The stair-step artifact were 3.0±0.9 and 3.1±0.9, respectively, in two groups; and there was also no statistical significance (P>0.05). The overall image quality were 3.0±0.8 and 3.1±0.9, respectively, in two group; and there was statistical significance (P>0.05). However, the effective dose were (5.24±0.52) mSv and (16.68±1.49) mSv, respectively, in two groups; and there was statistical significance (P<0.001). Conclusion: Compared with retrospective ECG-gated cardiac CTA, prospective ECG-gated cardiac CTA can reduce radiation dose about 68.6% , while maintaining the image quality which could be made diagnosis. (authors)

  11. Manifold learning based ECG-free free-breathing cardiac CINE MRI.

    Science.gov (United States)

    Usman, Muhammad; Atkinson, David; Kolbitsch, Christoph; Schaeffter, Tobias; Prieto, Claudia

    2015-06-01

    To present and validate a manifold learning (ML)-based method that can estimate both cardiac and respiratory navigator signals from electrocardiogram (ECG)-free free-breathing cardiac magnetic resonance imaging (MRI) data to achieve self-gated retrospective CINE reconstruction. In this work the use of the ML method is demonstrated for 2D cardiac CINE to achieve both cardiac and respiratory self-gating without the need of an external navigator or ECG signal. This is achieved by sequentially applying ML to two sets of retrospectively reconstructed real-time images with differing temporal resolutions. A 1D cardiac signal is estimated by applying ML to high temporal resolution real-time images reconstructed from the acquired data. Using the estimated cardiac signal, a 1D respiratory signal was obtained by applying the ML method to low temporal resolution images reconstructed from the same acquired data for each cardiac cycle. Data were acquired in five volunteers with a 2D golden angle radial trajectory in a balanced steady-state free precession (b-SSFP) acquisition. The accuracy of the estimated cardiac signal was calculated as the standard deviation of the temporal difference between the estimated signal and the recorded ECG. The correlation between the estimated respiratory signal and standard pencil beam navigator signal was evaluated. Gated CINE reconstructions (20 cardiac phases per cycle, temporal resolution ∼30 msec) using the estimated cardiac and respiratory signals were qualitatively compared against conventional ECG-gated breath-hold CINE acquisitions. Accurate cardiac signals were estimated with the proposed method, with an error standard deviation in comparison to ECG lower than 20 msec. Respiratory signals estimated with the proposed method achieved a mean cross-correlation of 94% with respect to standard pencil beam navigator signals. Good quality visual scores of 2.80 ± 0.45 (scores from 0, bad, to 4, excellent quality) were observed for the

  12. Tricuspid insufficiency detected by equilibrium gated radionuclide study

    International Nuclear Information System (INIS)

    Handler, B.; Pavel, D.G.; Lam, W.; Byrom, E.; Swiryn, S.; Pietras, R.; Rosen, K.M.

    1981-01-01

    The results of a gated radionuclide cardiac study are reported in a patient with biventricular failure and tricuspid insufficiency demonstrated by clinical evaluation, M-mode and 2-D sector echocardiography, and cardia catheterization. The processed gated radionuclide cardiac study showed a left ventricular/right ventricular stroke volume ratio of 0.5; expansion of the hepatic blood pool demonstrated by hepatic time activity curve and calculation of an '''expansion fraction''; and synchronous changes of count rate of the atrial and hepatic regions detected by phase analysis

  13. Myocardial blood flow quantification by Rb-82 cardiac PET/CT: A detailed reproducibility study between two semi-automatic analysis programs.

    Science.gov (United States)

    Dunet, Vincent; Klein, Ran; Allenbach, Gilles; Renaud, Jennifer; deKemp, Robert A; Prior, John O

    2016-06-01

    Several analysis software packages for myocardial blood flow (MBF) quantification from cardiac PET studies exist, but they have not been compared using concordance analysis, which can characterize precision and bias separately. Reproducible measurements are needed for quantification to fully develop its clinical potential. Fifty-one patients underwent dynamic Rb-82 PET at rest and during adenosine stress. Data were processed with PMOD and FlowQuant (Lortie model). MBF and myocardial flow reserve (MFR) polar maps were quantified and analyzed using a 17-segment model. Comparisons used Pearson's correlation ρ (measuring precision), Bland and Altman limit-of-agreement and Lin's concordance correlation ρc = ρ·C b (C b measuring systematic bias). Lin's concordance and Pearson's correlation values were very similar, suggesting no systematic bias between software packages with an excellent precision ρ for MBF (ρ = 0.97, ρc = 0.96, C b = 0.99) and good precision for MFR (ρ = 0.83, ρc = 0.76, C b = 0.92). On a per-segment basis, no mean bias was observed on Bland-Altman plots, although PMOD provided slightly higher values than FlowQuant at higher MBF and MFR values (P < .0001). Concordance between software packages was excellent for MBF and MFR, despite higher values by PMOD at higher MBF values. Both software packages can be used interchangeably for quantification in daily practice of Rb-82 cardiac PET.

  14. Fast Gated EPR Imaging of the Beating Heart: Spatiotemporally-Resolved 3D Imaging of Free Radical Distribution during the Cardiac Cycle

    Science.gov (United States)

    Chen, Zhiyu; Reyes, Levy A.; Johnson, David H.; Velayutham, Murugesan; Yang, Changjun; Samouilov, Alexandre; Zweier, Jay L.

    2012-01-01

    In vivo or ex vivo electron paramagnetic resonance imaging (EPRI) is a powerful technique for determining the spatial distribution of free radicals and other paramagnetic species in living organs and tissues. However, applications of EPRI have been limited by long projection acquisition times and the consequent fact that rapid gated EPRI was not possible. Hence in vivo EPRI typically provided only time-averaged information. In order to achieve direct gated EPRI, a fast EPR acquisition scheme was developed to decrease EPR projection acquisition time down to 10 – 20 ms, along with corresponding software and instrumentation to achieve fast gated EPRI of the isolated beating heart with submillimeter spatial resolution in as little as 2 to 3 minutes. Reconstructed images display temporal and spatial variations of the free radical distribution, anatomical structure, and contractile function within the rat heart during the cardiac cycle. PMID:22473660

  15. Correlation between semiquantitative myocardial perfusion score and absolute myocardial flow in 13N-ammonia PET

    International Nuclear Information System (INIS)

    Lee, Byeong Il; Kim, Jung Young; Min, Jung Joon; Song, Ho Chun; Bom, Hee Seung; Kim, Kye Hun; Kim, Su Jin; Lee, Jae Sung

    2007-01-01

    13 N-ammonia is a well known radiopharmaceutical for the measurement of a myocardial blood flow (MBF) non-invasively using PET-CT. In this study, we investigated a correlation between MBF obtained from dynamic imaging and myocardial perfusion score (MPS) obtained from static imaging for usefulness of cardiac PET study. Twelve patients (11 males, 1 female, 57.9 ± 8.6 years old) with suspicious coronary artery disease underwent PET-CT scan. Dynamic scans (6 min: 5 sec X 12, 10 sec X 6, 20 sec X 3, and 30 sec X 6) were initiated simultaneously with bolus injection of 11 MBq/kg 13 N-ammonia to acquire rest and stress image. Gating image was acquired during 13 minutes continuously. Nine-segment model (4 basal walls, 4 mid walls, and apex) was used for a measurement of MBF. Time activity curve of input function and myocardium was extracted from ROI methods in 9 regions for quantification. The MPS were evaluated using quantitative analysis software. To compare between 20-segment model and 9-segment model, 6 basal segments were excluded and averaged segmental scores were used. There are weak correlation between MBF (rest, 0.18-2.38 ml/min/g; stress, 0.40-4.95 ml/min/g) and MPS (rest 22-91%, stress, 14-90%), however the correlation coefficient between corrected MBF and MPS in rest state was higher than stress state (rest r=0.59; stress r=0.80). As a thickening increased, correlation between MBF and MPS also showed good correlation at each segments. Corrected and translated MPS as its characteristics using 13 N-ammonia showed good correlation with absolute MBF measured by dynamic image in this study. Therefore, we showed MPS is one of good indices which reflect MBF. We anticipate PET-CT could be used as useful tool for evaluation of myocardial function in nuclear cardiac study

  16. Fourier analysis of multi-gated cardiac blood-pool data in patients with congenital heart diseases, (2). Assessment of diseases with complex cardiac anomalies, especially tetralogy of Fallot

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Kan; Maeda, Hisato; Yamaguchi, Nobuo; Nakamura, Kazuyoshi; Matsumura, Kaname; Nakagawa, Tsuyoshi; Sakurai, Minoru; Aoki, Kenzo

    1985-04-01

    The clinical usefulness of Fourier analysis of multi-gated cardiac blood-pool data was evaluated in 18 subjects with normal cardiac functions and 14 patients with complex cardiac anomalies (ten with tetralogy of Fallot, two with tricuspid atresia (TA), one with double-outlet right ventricle (DORV), and one with Ebstein's anomaly (EA)). Using global ventricular time-activity curves, the phase and amplitude at fundamental frequency were calculated, and emptying patterns of the left and right ventricles (LV, RV) were evaluated by phase difference (D(phase)=RV phase minus LV phase) and amplitude ratio of RV to LV (R(amp)). In patients with TOF, mean values of D (phase) and R(amp) were 25.3 +- 10.5 degrees and 13.5 +- 0.49 respectively and significantly larger than those of normal subjects. D (phase) became larger in inverse proportion to the ratio of pulmonary-to-systemic blood flow and there was an inverse linear correlation between these two variables. On visual interpretation of functional images, the dynamic property of hypoplastic ventricles could be easily estimated in patients with TA or DORV. In a case with EA, the atrialized RV was shown clearly as a hypokinetic, atrial phase area. This method is valuable for pathophysiologic investigation of diseases with complex cardiac anomalies. (author).

  17. Self-gated golden-angle spiral 4D flow MRI.

    Science.gov (United States)

    Bastkowski, Rene; Weiss, Kilian; Maintz, David; Giese, Daniel

    2018-01-17

    The acquisition of 4D flow magnetic resonance imaging (MRI) in cardiovascular applications has recently made large progress toward clinical feasibility. The need for simultaneous compensation of cardiac and breathing motion still poses a challenge for widespread clinical use. Especially, breathing motion, addressed by gating approaches, can lead to unpredictable and long scan times. The current work proposes a time-efficient self-gated 4D flow sequence that exploits up to 100% of the acquired data and operates at a predictable scan time. A self-gated golden-angle spiral 4D flow sequence was implemented and tested in 10 volunteers. Data were retrospectively binned into respiratory and cardiac states and reconstructed using a conjugate-gradient sensitivity encoding reconstruction. Net flow curves, stroke volumes, and peak flow in the aorta were evaluated and compared to a conventional Cartesian 4D flow sequence. Additionally, flow quantities reconstructed from 50% to 100% of the self-gated 4D flow data were compared. Self-gating signals for respiratory and cardiac motion were extracted for all volunteers. Flow quantities were in agreement with the standard Cartesian scan. Mean differences in stroke volumes and peak flow of 7.6 ± 11.5 and 4.0 ± 79.9 mL/s were obtained, respectively. By retrospectively increasing breathing navigator efficiency while decreasing acquisition times (15:06-07:33 minutes), 50% of the acquired data were sufficient to measure stroke volumes with errors under 9.6 mL. The feasibility to acquire respiratory and cardiac self-gated 4D flow data at a predictable scan time was demonstrated. Magn Reson Med, 2018. © 2018 International Society for Magnetic Resonance in Medicine. © 2018 International Society for Magnetic Resonance in Medicine.

  18. Investigation of time-of-flight benefits in an LYSO-based PET/CT scanner: A Monte Carlo study using GATE

    International Nuclear Information System (INIS)

    Geramifar, P.; Ay, M.R.; Shamsaie Zafarghandi, M.; Sarkar, S.; Loudos, G.; Rahmim, A.

    2011-01-01

    The advent of fast scintillators yielding great light yield and/or stopping power, along with advances in photomultiplier tubes and electronics, have rekindled interest in time-of-flight (TOF) PET. Because the potential performance improvements offered by TOF PET are substantial, efforts to improve PET timing should prove very fruitful. In this study, we performed Monte Carlo simulations to explore what gains in PET performance could be achieved if the coincidence resolving time (CRT) in the LYSO-based PET component of Discovery RX PET/CT scanner were improved. For this purpose, the GATE Monte Carlo package was utilized, providing the ability to model and characterize various physical phenomena in PET imaging. For the present investigation, count rate performance and signal to noise ratio (SNR) values in different activity concentrations were simulated for different coincidence timing windows of 4, 5.85, 6, 6.5, 8, 10 and 12 ns and with different CRTs of 100-900 ps FWHM involving 50 ps FWHM increments using the NEMA scatter phantom. Strong evidence supporting robustness of the simulations was found as observed in the good agreement between measured and simulated data for the cases of estimating axial sensitivity, axial and transaxial detection position, gamma non-collinearity angle distribution and positron annihilation distance. In the non-TOF context, the results show that the random event rate can be reduced by using narrower coincidence timing window widths, demonstrating considerable enhancements in the peak noise equivalent count rate (NECR) performance. The peak NECR had increased by ∼50% when utilizing the coincidence window width of 4 ns. At the same time, utilization of TOF information resulted in improved NECR and SNR with the dramatic reduction of random coincidences as a function of CRT. For example, with CRT of 500 ps FWHM, a factor of 2.3 reduction in random rates, factor of 1.5 increase in NECR and factor of 2.1 improvement in SNR is achievable

  19. Investigation of time-of-flight benefits in an LYSO-based PET/CT scanner: A Monte Carlo study using GATE

    Energy Technology Data Exchange (ETDEWEB)

    Geramifar, P. [Faculty of Physics and Nuclear Engineering, Amir Kabir University of Technology (Tehran Polytechnic), Tehran (Iran, Islamic Republic of); Research Center for Science and Technology in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Research Institute for Nuclear Medicine, Tehran University of Medical Sciences, Shariati Hospital, Tehran (Iran, Islamic Republic of); Ay, M.R., E-mail: mohammadreza_ay@tums.ac.ir [Research Center for Science and Technology in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Research Institute for Nuclear Medicine, Tehran University of Medical Sciences, Shariati Hospital, Tehran (Iran, Islamic Republic of); Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Shamsaie Zafarghandi, M. [Faculty of Physics and Nuclear Engineering, Amir Kabir University of Technology (Tehran Polytechnic), Tehran (Iran, Islamic Republic of); Sarkar, S. [Research Center for Science and Technology in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Research Institute for Nuclear Medicine, Tehran University of Medical Sciences, Shariati Hospital, Tehran (Iran, Islamic Republic of); Loudos, G. [Department of Medical Instruments Technology, Technological Educational Institute, Athens (Greece); Rahmim, A. [Department of Radiology, School of Medicine, Johns Hopkins University, Baltimore (United States); Department of Electrical and Computer Engineering, School of Engineering, Johns Hopkins University, Baltimore (United States)

    2011-06-11

    The advent of fast scintillators yielding great light yield and/or stopping power, along with advances in photomultiplier tubes and electronics, have rekindled interest in time-of-flight (TOF) PET. Because the potential performance improvements offered by TOF PET are substantial, efforts to improve PET timing should prove very fruitful. In this study, we performed Monte Carlo simulations to explore what gains in PET performance could be achieved if the coincidence resolving time (CRT) in the LYSO-based PET component of Discovery RX PET/CT scanner were improved. For this purpose, the GATE Monte Carlo package was utilized, providing the ability to model and characterize various physical phenomena in PET imaging. For the present investigation, count rate performance and signal to noise ratio (SNR) values in different activity concentrations were simulated for different coincidence timing windows of 4, 5.85, 6, 6.5, 8, 10 and 12 ns and with different CRTs of 100-900 ps FWHM involving 50 ps FWHM increments using the NEMA scatter phantom. Strong evidence supporting robustness of the simulations was found as observed in the good agreement between measured and simulated data for the cases of estimating axial sensitivity, axial and transaxial detection position, gamma non-collinearity angle distribution and positron annihilation distance. In the non-TOF context, the results show that the random event rate can be reduced by using narrower coincidence timing window widths, demonstrating considerable enhancements in the peak noise equivalent count rate (NECR) performance. The peak NECR had increased by {approx}50% when utilizing the coincidence window width of 4 ns. At the same time, utilization of TOF information resulted in improved NECR and SNR with the dramatic reduction of random coincidences as a function of CRT. For example, with CRT of 500 ps FWHM, a factor of 2.3 reduction in random rates, factor of 1.5 increase in NECR and factor of 2.1 improvement in SNR is

  20. Alternans promotion in cardiac electrophysiology models by delay differential equations.

    Science.gov (United States)

    Gomes, Johnny M; Dos Santos, Rodrigo Weber; Cherry, Elizabeth M

    2017-09-01

    Cardiac electrical alternans is a state of alternation between long and short action potentials and is frequently associated with harmful cardiac conditions. Different dynamic mechanisms can give rise to alternans; however, many cardiac models based on ordinary differential equations are not able to reproduce this phenomenon. A previous study showed that alternans can be induced by the introduction of delay differential equations (DDEs) in the formulations of the ion channel gating variables of a canine myocyte model. The present work demonstrates that this technique is not model-specific by successfully promoting alternans using DDEs for five cardiac electrophysiology models that describe different types of myocytes, with varying degrees of complexity. By analyzing results across the different models, we observe two potential requirements for alternans promotion via DDEs for ionic gates: (i) the gate must have a significant influence on the action potential duration and (ii) a delay must significantly impair the gate's recovery between consecutive action potentials.

  1. Alternans promotion in cardiac electrophysiology models by delay differential equations

    Science.gov (United States)

    Gomes, Johnny M.; dos Santos, Rodrigo Weber; Cherry, Elizabeth M.

    2017-09-01

    Cardiac electrical alternans is a state of alternation between long and short action potentials and is frequently associated with harmful cardiac conditions. Different dynamic mechanisms can give rise to alternans; however, many cardiac models based on ordinary differential equations are not able to reproduce this phenomenon. A previous study showed that alternans can be induced by the introduction of delay differential equations (DDEs) in the formulations of the ion channel gating variables of a canine myocyte model. The present work demonstrates that this technique is not model-specific by successfully promoting alternans using DDEs for five cardiac electrophysiology models that describe different types of myocytes, with varying degrees of complexity. By analyzing results across the different models, we observe two potential requirements for alternans promotion via DDEs for ionic gates: (i) the gate must have a significant influence on the action potential duration and (ii) a delay must significantly impair the gate's recovery between consecutive action potentials.

  2. Modern nuclear cardiac imaging in diagnosis and clinical management of patients with left ventricular dysfunction.

    Science.gov (United States)

    Abidov, A; Hachamovitch, R; Berman, D S

    2004-12-01

    Congestive heart failure (CHF) has become a large social burden in modern Western society, with very high morbidity and mortality and extremely large financial costs. The largest cause of CHF is coronary heart disease, with ventricular dysfunction that may or may not be reversible by revascularization. Thus, evaluation of the viable myocardial tissue in patients with ischemic left ventricular (LV) dysfunction has important clinical and therapeutic implications. Furthermore, since patients with ventricular dysfunction are at higher operative risk, cardiologists and cardiac surgeons are commonly faced with issues regarding the balance between the potential risk vs benefit of revascularization procedures. Cardiac nuclear imaging [myocardial perfusion SPECT (MPS) and positron emission tomography (PET)] provide objective information that augments standard clinical and angiographic assessments of patients with ventricular dysfunction with respect to diagnosis (etiology), prognosis, and potential benefit from intervention. Development of the technology and methodology of gated MPS, now the routine method for MPS, allows assessment of the extent and severity of inducible ischemia as well as hypoperfused but viable myocardium, and also provides measurements of LV ejection fraction, regional wall motion, LV volume measurements, diastolic function and LV geometry. With PET, myocardial metabolism and blood flow reserve can be added to the measurements provided by nuclear cardiology procedures. This paper provides insight into the current evidence regarding settings in which nuclear cardiac imaging procedures are helpful in assessment of patients in the setting of coronary artery disease with severe LV dysfunction. A risk-benefit approach to MPS results is proposed, with principal focus on identifying patients at risk for major cardiac events who may benefit from myocardial revascularization.

  3. Optimization of Rb-82 PET acquisition and reconstruction protocols for myocardial perfusion defect detection

    Science.gov (United States)

    Tang, Jing; Rahmim, Arman; Lautamäki, Riikka; Lodge, Martin A.; Bengel, Frank M.; Tsui, Benjamin M. W.

    2009-05-01

    The purpose of this study is to optimize the dynamic Rb-82 cardiac PET acquisition and reconstruction protocols for maximum myocardial perfusion defect detection using realistic simulation data and task-based evaluation. Time activity curves (TACs) of different organs under both rest and stress conditions were extracted from dynamic Rb-82 PET images of five normal patients. Combined SimSET-GATE Monte Carlo simulation was used to generate nearly noise-free cardiac PET data from a time series of 3D NCAT phantoms with organ activities modeling different pre-scan delay times (PDTs) and total acquisition times (TATs). Poisson noise was added to the nearly noise-free projections and the OS-EM algorithm was applied to generate noisy reconstructed images. The channelized Hotelling observer (CHO) with 32× 32 spatial templates corresponding to four octave-wide frequency channels was used to evaluate the images. The area under the ROC curve (AUC) was calculated from the CHO rating data as an index for image quality in terms of myocardial perfusion defect detection. The 0.5 cycle cm-1 Butterworth post-filtering on OS-EM (with 21 subsets) reconstructed images generates the highest AUC values while those from iteration numbers 1 to 4 do not show different AUC values. The optimized PDTs for both rest and stress conditions are found to be close to the cross points of the left ventricular chamber and myocardium TACs, which may promote an individualized PDT for patient data processing and image reconstruction. Shortening the TATs for <~3 min from the clinically employed acquisition time does not affect the myocardial perfusion defect detection significantly for both rest and stress studies.

  4. WE-AB-204-03: A Novel 3D Printed Phantom for 4D PET/CT Imaging and SIB Radiotherapy Verification

    International Nuclear Information System (INIS)

    Soultan, D; Murphy, J; Moiseenko, V; Cervino, L; Gill, B

    2015-01-01

    Purpose: To construct and test a 3D printed phantom designed to mimic variable PET tracer uptake seen in lung tumor volumes. To assess segmentation accuracy of sub-volumes of the phantom following 4D PET/CT scanning with ideal and patient-specific respiratory motion. To plan, deliver and verify delivery of PET-driven, gated, simultaneous integrated boost (SIB) radiotherapy plans. Methods: A set of phantoms and inserts were designed and manufactured for a realistic representation of lung cancer gated radiotherapy steps from 4D PET/CT scanning to dose delivery. A cylindrical phantom (40x 120 mm) holds inserts for PET/CT scanning. The novel 3D printed insert dedicated to 4D PET/CT mimics high PET tracer uptake in the core and lower uptake in the periphery. This insert is a variable density porous cylinder (22.12×70 mm), ABS-P430 thermoplastic, 3D printed by uPrint SE Plus with inner void volume (5.5×42 mm). The square pores (1.8×1.8 mm2 each) fill 50% of outer volume, resulting in a 2:1 SUV ratio of PET-tracer in the void volume with respect to porous volume. A matching in size cylindrical phantom is dedicated to validate gated radiotherapy. It contains eight peripheral holes matching the location of the porous part of the 3D printed insert, and one central hole. These holes accommodate adaptors for Farmer-type ion chamber and cells vials. Results: End-to-end test were performed from 4D PET/CT scanning to transferring data to the planning system and target volume delineation. 4D PET/CT scans were acquired of the phantom with different respiratory motion patterns and gating windows. A measured 2:1 18F-FDG SUV ratio between inner void and outer volume matched the 3D printed design. Conclusion: The novel 3D printed phantom mimics variable PET tracer uptake typical of tumors. Obtained 4D PET/CT scans are suitable for segmentation, treatment planning and delivery in SIB gated treatments of NSCLC

  5. Feasibility of a semi-automated contrast-oriented algorithm for tumor segmentation in retrospectively gated PET images: phantom and clinical validation

    Science.gov (United States)

    Carles, Montserrat; Fechter, Tobias; Nemer, Ursula; Nanko, Norbert; Mix, Michael; Nestle, Ursula; Schaefer, Andrea

    2015-12-01

    PET/CT plays an important role in radiotherapy planning for lung tumors. Several segmentation algorithms have been proposed for PET tumor segmentation. However, most of them do not take into account respiratory motion and are not well validated. The aim of this work was to evaluate a semi-automated contrast-oriented algorithm (COA) for PET tumor segmentation adapted to retrospectively gated (4D) images. The evaluation involved a wide set of 4D-PET/CT acquisitions of dynamic experimental phantoms and lung cancer patients. In addition, segmentation accuracy of 4D-COA was compared with four other state-of-the-art algorithms. In phantom evaluation, the physical properties of the objects defined the gold standard. In clinical evaluation, the ground truth was estimated by the STAPLE (Simultaneous Truth and Performance Level Estimation) consensus of three manual PET contours by experts. Algorithm evaluation with phantoms resulted in: (i) no statistically significant diameter differences for different targets and movements (Δ φ =0.3+/- 1.6 mm); (ii) reproducibility for heterogeneous and irregular targets independent of user initial interaction and (iii) good segmentation agreement for irregular targets compared to manual CT delineation in terms of Dice Similarity Coefficient (DSC  =  0.66+/- 0.04 ), Positive Predictive Value (PPV  =  0.81+/- 0.06 ) and Sensitivity (Sen.  =  0.49+/- 0.05 ). In clinical evaluation, the segmented volume was in reasonable agreement with the consensus volume (difference in volume (%Vol)  =  40+/- 30 , DSC  =  0.71+/- 0.07 and PPV  =  0.90+/- 0.13 ). High accuracy in target tracking position (Δ ME) was obtained for experimental and clinical data (Δ ME{{}\\text{exp}}=0+/- 3 mm; Δ ME{{}\\text{clin}}=0.3+/- 1.4 mm). In the comparison with other lung segmentation methods, 4D-COA has shown the highest volume accuracy in both experimental and clinical data. In conclusion, the accuracy in volume

  6. Systemic and inflammatory disorders involving the heart: the role of PET imaging

    International Nuclear Information System (INIS)

    JUNEAU, Daniel; ERTHAL, Fernanda; ALZAHRANI, Atif; ALENAZY, Ali; NERY, Pablo B.; BEANLANDS, Rob S.; CHOW, Benjamin J.

    2016-01-01

    Cardiac inflammatory disorders, either primarily cardiac or secondary to a systemic process, are associated with significant morbidity and/or mortality. Their diagnosis can be challenging, especially due to significant overlap in their clinical presentation with other cardiac diseases. Recent publications have investigated the potential diagnostic role of positron emission tomography (PET) imaging in these patients. Most of the available literature is focused on Fluorine-18 fluorodeoxyglucose (FDG), a tracer which has already demonstrated its use in other inflammatory and infectious processes. PET imaging can help in the diagnosis, prognosis and follow-up in a variety of cardiac inflammatory processes, including infective endocarditis, cardiac implantable electronic device infection, pericarditis, myocarditis, sarcoidosis and amyloidosis. PET’s ability to depict metabolic changes and abnormalities, sometime even before the onset of any anatomical changes, can be a significant advantage over standard anatomical imaging. PET appears to be particularly useful in cases where standard investigation is non-diagnostic or equivocal.

  7. Incremental value of PET and MRI in the evaluation of cardiovascular abnormalities.

    Science.gov (United States)

    Chalian, Hamid; O'Donnell, James K; Bolen, Michael; Rajiah, Prabhakar

    2016-08-01

    The cardiovascular system is affected by a wide range of pathological processes, including neoplastic, inflammatory, ischemic, and congenital aetiology. Magnetic resonance imaging (MRI) and positron emission tomography (PET) are state-of-the-art imaging modalities used in the evaluation of these cardiovascular disorders. MRI has good spatial and temporal resolutions, tissue characterization and multi-planar imaging/reconstruction capabilities, which makes it useful in the evaluation of cardiac morphology, ventricular and valvar function, disease characterization, and evaluation of myocardial viability. FDG-PET provides valuable information on the metabolic activity of the cardiovascular diseases, including ischemia, inflammation, and neoplasm. MRI and FDG-PET can provide complementary information on the evaluation of several cardiovascular disorders. For example, in cardiac masses, FDG-PET provides the metabolic information for indeterminate cardiac masses. MRI can be used for localizing and characterizing abnormal hypermetabolic foci identified incidentally on PET scan and also for local staging. A recent advance in imaging technology has been the development of integrated PET/MRI systems that utilize the advantages of PET and MRI in a single examination. The goal of this manuscript is to provide a comprehensive review on the incremental value of PET and MRI in the evaluation of cardiovascular diseases. • MRI has good spatial and temporal resolutions, tissue characterization, and multi-planar reconstruction • FDG-PET provides valuable information on the metabolic activity of cardiovascular disorders • PET and MRI provide complementary information on the evaluation of cardiovascular disorders.

  8. Accurate estimation of global and regional cardiac function by retrospectively gated multidetector row computed tomography. Comparison with cine magnetic resonance imaging

    International Nuclear Information System (INIS)

    Belge, Benedicte; Pasquet, Agnes; Vanoverschelde, Jean-Louis J.; Coche, Emmanuel; Gerber, Bernhard L.

    2006-01-01

    Retrospective reconstruction of ECG-gated images at different parts of the cardiac cycle allows the assessment of cardiac function by multi-detector row CT (MDCT) at the time of non-invasive coronary imaging. We compared the accuracy of such measurements by MDCT to cine magnetic resonance (MR). Forty patients underwent the assessment of global and regional cardiac function by 16-slice MDCT and cine MR. Left ventricular (LV) end-diastolic and end-systolic volumes estimated by MDCT (134±51 and 67±56 ml) were similar to those by MR (137±57 and 70±60 ml, respectively; both P=NS) and strongly correlated (r=0.92 and r=0.95, respectively; both P<0.001). Consequently, LV ejection fractions by MDCT and MR were also similar (55±21 vs. 56±21%; P=NS) and highly correlated (r=0.95; P<0.001). Regional end-diastolic and end-systolic wall thicknesses by MDCT were highly correlated (r=0.84 and r=0.92, respectively; both P<0.001), but significantly lower than by MR (8.3±1.8 vs. 8.8±1.9 mm and 12.7±3.4 vs. 13.3±3.5 mm, respectively; both P<0.001). Values of regional wall thickening by MDCT and MR were similar (54±30 vs. 51±31%; P=NS) and also correlated well (r=0.91; P<0.001). Retrospectively gated MDCT can accurately estimate LV volumes, EF and regional LV wall thickening compared to cine MR. (orig.)

  9. Evaluation of the combined effects of target size, respiratory motion and background activity on 3D and 4D PET/CT images

    International Nuclear Information System (INIS)

    Park, Sang-June; Ionascu, Dan; Killoran, Joseph; Chin, Lee; Berbeco, Ross; Mamede, Marcelo; Gerbaudo, Victor H

    2008-01-01

    Gated (4D) PET/CT has the potential to greatly improve the accuracy of radiotherapy at treatment sites where internal organ motion is significant. However, the best methodology for applying 4D-PET/CT to target definition is not currently well established. With the goal of better understanding how to best apply 4D information to radiotherapy, initial studies were performed to investigate the effect of target size, respiratory motion and target-to-background activity concentration ratio (TBR) on 3D (ungated) and 4D PET images. Using a PET/CT scanner with 4D or gating capability, a full 3D-PET scan corrected with a 3D attenuation map from 3D-CT scan and a respiratory gated (4D) PET scan corrected with corresponding attenuation maps from 4D-CT were performed by imaging spherical targets (0.5-26.5 mL) filled with 18 F-FDG in a dynamic thorax phantom and NEMA IEC body phantom at different TBRs (infinite, 8 and 4). To simulate respiratory motion, the phantoms were driven sinusoidally in the superior-inferior direction with amplitudes of 0, 1 and 2 cm and a period of 4.5 s. Recovery coefficients were determined on PET images. In addition, gating methods using different numbers of gating bins (1-20 bins) were evaluated with image noise and temporal resolution. For evaluation, volume recovery coefficient, signal-to-noise ratio and contrast-to-noise ratio were calculated as a function of the number of gating bins. Moreover, the optimum thresholds which give accurate moving target volumes were obtained for 3D and 4D images. The partial volume effect and signal loss in the 3D-PET images due to the limited PET resolution and the respiratory motion, respectively were measured. The results show that signal loss depends on both the amplitude and pattern of respiratory motion. However, the 4D-PET successfully recovers most of the loss induced by the respiratory motion. The 5-bin gating method gives the best temporal resolution with acceptable image noise. The results based on the 4D

  10. Basic study of entire whole-body PET scanners based on the OpenPET geometry

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Eiji, E-mail: rush@nirs.go.j [National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Yamaya, Taiga; Nishikido, Fumihiko; Inadama, Naoko; Murayama, Hideo [National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan)

    2010-09-21

    A conventional PET scanner has a 15-25 cm axial field-of-view (FOV) and images a whole body using about six bed positions. An OpenPET geometry can extend the axial FOV with a limited number of detectors. The entire whole-body PET scanner must be able to process a large amount of data effectively. In this work, we study feasibility of the fully 3D entire whole-body PET scanner using the GATE simulation. The OpenPET has 12 block detector rings with the ring diameter of 840 mm and each block detector ring consists of 48 depth-of-interaction (DOI) detectors. The OpenPET has the axial length of 895.95 mm with five parts of 58.95 mm open gaps. The OpenPET has higher single data loss than a conventional PET scanner at grouping circuits. NECR of the OpenPET decreases by single data loss. But single data loss is mitigated by separating the axially arranged detector into two parts. Also, multiple coincidences are found to be important for the entire whole-body PET scanner. The entire whole-body PET scanner with the OpenPET geometry promises to provide a large axial FOV with the open space and to have sufficient performance values. But single data loss at the grouping circuits and multiple coincidences are limited to the peak noise equivalent count rate (NECR) for the entire whole-body PET scanner.

  11. Clinical validation of free breathing respiratory triggered retrospectively cardiac gated cine balanced steady-state free precession cardiovascular magnetic resonance in sedated children

    OpenAIRE

    Krishnamurthy, Rajesh; Pednekar, Amol; Atweh, Lamya A; Vogelius, Esben; Chu, Zili David; Zhang, Wei; Maskatia, Shiraz; Masand, Prakash; Morris, Shaine A; Krishnamurthy, Ramkumar; Muthupillai, Raja

    2015-01-01

    Background Cine balanced steady-state free precession (SSFP), the preferred sequence for ventricular function, demands uninterrupted radio frequency (RF) excitation to maintain the steady-state during suspended respiration. This is difficult to accomplish in sedated children. In this work, we validate a respiratory triggered (RT) SSFP sequence that drives the magnetization to steady-state before commencing retrospectively cardiac gated cine acquisition in a sedated pediatric population. Metho...

  12. Free-breathing steady-state free precession cine cardiac magnetic resonance with respiratory navigator gating.

    Science.gov (United States)

    Moghari, Mehdi H; Komarlu, Rukmini; Annese, David; Geva, Tal; Powell, Andrew J

    2015-04-01

    To develop and validate a respiratory motion compensation method for free-breathing cardiac cine imaging. A free-breathing navigator-gated cine steady-state free precession acquisition (Cine-Nav) was developed which preserves the equilibrium state of the net magnetization vector, maintains the high spatial and temporal resolutions of standard breath-hold (BH) acquisition, and images entire cardiac cycle. Cine image data is accepted only from cardiac cycles occurring entirely during end-expiration. Prospective validation was performed in 10 patients by obtaining in each three complete ventricular image stacks with different respiratory motion compensation approaches: (1) BH, (2) free-breathing with 3 signal averages (3AVG), and (3) free-breathing with Cine-Nav. The subjective image quality score (1 = worst, 4 = best) for Cine-Nav (3.8 ± 0.4) was significantly better than for 3AVG (2.2 ± 0.5, P = 0.002), and similar to BH (4.0 ± 0.0, P = 0.13). The blood-to-myocardium contrast ratio for Cine-Nav (6.3 ± 1.5) was similar to BH (5.9 ± 1.6, P = 0.52) and to 3AVG (5.6 ± 2.5, P = 0.43). There were no significant differences between Cine-Nav and BH for the ventricular volumes and mass. In contrast, there were significant differences between 3AVG and BH in all of these measurements but right ventricular mass. Free-breathing cine imaging with Cine-Nav yielded comparable image quality and ventricular measurements to BH, and was superior to 3AVG. © 2014 Wiley Periodicals, Inc.

  13. Cardiac and pericardial tumors: A potential application of positron emission tomography-magnetic resonance imaging.

    Science.gov (United States)

    Fathala, Ahmed; Abouzied, Mohei; AlSugair, Abdul-Aziz

    2017-07-26

    Cardiac and pericardial masses may be neoplastic, benign and malignant, non-neoplastic such as thrombus or simple pericardial cysts, or normal variants cardiac structure can also be a diagnostic challenge. Currently, there are several imaging modalities for diagnosis of cardiac masses; each technique has its inherent advantages and disadvantages. Echocardiography, is typically the initial test utilizes in such cases, Echocardiography is considered the test of choice for evaluation and detection of cardiac mass, it is widely available, portable, with no ionizing radiation and provides comprehensive evaluation of cardiac function and valves, however, echocardiography is not very helpful in many cases such as evaluation of extracardiac extension of mass, poor tissue characterization, and it is non diagnostic in some cases. Cross sectional imaging with cardiac computed tomography provides a three dimensional data set with excellent spatial resolution but utilizes ionizing radiation, intravenous iodinated contrast and relatively limited functional evaluation of the heart. Cardiac magnetic resonance imaging (CMR) has excellent contrast resolution that allows superior soft tissue characterization. CMR offers comprehensive evaluation of morphology, function, tissue characterization. The great benefits of CMR make CMR a highly useful tool in the assessment of cardiac masses. (Fluorine 18) fluorodeoxygluocse (FDG) positron emission tomography (PET) has become a corner stone in several oncological application such as tumor staging, restaging, treatment efficiency, FDG is a very useful imaging modality in evaluation of cardiac masses. A recent advance in the imaging technology has been the development of integrated PET-MRI system that utilizes the advantages of PET and MRI in a single examination. FDG PET-MRI provides complementary information on evaluation of cardiac masses. The purpose of this review is to provide several clinical scenarios on the incremental value of PET

  14. Motion correction in thoracic positron emission tomography

    CERN Document Server

    Gigengack, Fabian; Dawood, Mohammad; Schäfers, Klaus P

    2015-01-01

    Respiratory and cardiac motion leads to image degradation in Positron Emission Tomography (PET), which impairs quantification. In this book, the authors present approaches to motion estimation and motion correction in thoracic PET. The approaches for motion estimation are based on dual gating and mass-preserving image registration (VAMPIRE) and mass-preserving optical flow (MPOF). With mass-preservation, image intensity modulations caused by highly non-rigid cardiac motion are accounted for. Within the image registration framework different data terms, different variants of regularization and parametric and non-parametric motion models are examined. Within the optical flow framework, different data terms and further non-quadratic penalization are also discussed. The approaches for motion correction particularly focus on pipelines in dual gated PET. A quantitative evaluation of the proposed approaches is performed on software phantom data with accompanied ground-truth motion information. Further, clinical appl...

  15. The values of myocardial tomography imaging and gated cardiac blood pool imaging in detecting left ventricular aneurysm

    International Nuclear Information System (INIS)

    Zhu Mei; Pan Zhongyun; Li Jinhui

    1992-01-01

    The sensitivity and specificity of myocardial tomography imaging and gated cardiac blood-pool imaging in detecting LVA were studied in 36 normal subjects and 68 patients with myocardial infarction. The sensitivities of exercise and rest myocardial imaging in detecting LVA were 85% and 77.3% respectively. The specificity of both is 95.5%. The sensitivity of cinema display, phase analysis and left ventricular phase shift in evaluating LVA were 86.7%, 86.7%, 100% respectively. Their specificity were all 100%. It is concluded that blood pool imaging is of choice for the diagnosis of LVA, and that myocardial imaging could also demonstrate LVA during diagnosing myocardial infarction

  16. Clinical usefulness of T1-201 myocardial scintigraphy and diastolic phase index by gated cardiac blood pool imaging in patients with hypertrophic cardiomyopathy

    International Nuclear Information System (INIS)

    Ohmine, Hiromi; Nishimura, Tsunehiko; Hayashida, Kohhei; Uehara, Toshiisa; Kozuka, Takahiro

    1984-01-01

    Tl-201 myocardial scintigraphy and gated cardiac blood pool imaging with Tc-99m were performed at rest in 24 hypertrophic cardiomyopathy (HCM) and 11 normal subjects. Based on visual analysis of Tl-201 myocardial scintigraphies, patients with HCM were subdivided into the following four groups; type I: non-obstructive, type II: obstructive, type III: asymmetric septal hypertrophy, type IV: apical hypertrophy. Characteristic myocardial hypertrophy of each group was also confirmed from the profile curves of circumferential analysis. First third filling fraction (1/3 FF) and mean first third filling rate (1/3 FRm) were obtained from gated cardiac blood pool imaging. As compaired with the normal subjects, 1/3 FF was not so sensitive for the detection of left ventricular hypertrophy. Mean+-S.D. of 1.3 FRm were 1.96+-0.56/sec (normal group), 1.30+-0.44/sec (typ e I), 1.18+-0.63/sec (type II), 1.17+-0.14/sec (type III), and 1.26+-0.03/sec (type IV). We considered that 1/3 FRm was a useful diastolic phase index in the diagnosis of HCM. (author)

  17. Echocardiography as an indication of continuous-time cardiac quiescence

    Science.gov (United States)

    Wick, C. A.; Auffermann, W. F.; Shah, A. J.; Inan, O. T.; Bhatti, P. T.; Tridandapani, S.

    2016-07-01

    Cardiac computed tomography (CT) angiography using prospective gating requires that data be acquired during intervals of minimal cardiac motion to obtain diagnostic images of the coronary vessels free of motion artifacts. This work is intended to assess B-mode echocardiography as a continuous-time indication of these quiescent periods to determine if echocardiography can be used as a cost-efficient, non-ionizing modality to develop new prospective gating techniques for cardiac CT. These new prospective gating approaches will not be based on echocardiography itself but on CT-compatible modalities derived from the mechanics of the heart (e.g. seismocardiography and impedance cardiography), unlike the current standard electrocardiogram. To this end, echocardiography and retrospectively-gated CT data were obtained from ten patients with varied cardiac conditions. CT reconstructions were made throughout the cardiac cycle. Motion of the interventricular septum (IVS) was calculated from both echocardiography and CT reconstructions using correlation-based, deviation techniques. The IVS was chosen because it (1) is visible in echocardiography images, whereas the coronary vessels generally are not, and (2) has been shown to be a suitable indicator of cardiac quiescence. Quiescent phases were calculated as the minima of IVS motion and CT volumes were reconstructed for these phases. The diagnostic quality of the CT reconstructions from phases calculated from echocardiography and CT data was graded on a four-point Likert scale by a board-certified radiologist fellowship-trained in cardiothoracic radiology. Using a Wilcoxon signed-rank test, no significant difference in the diagnostic quality of the coronary vessels was found between CT volumes reconstructed from echocardiography- and CT-selected phases. Additionally, there was a correlation of 0.956 between the echocardiography- and CT-selected phases. This initial work suggests that B-mode echocardiography can be used as a

  18. ⁶⁸Ga-DOTA-TOC-PET/CT detects heart metastases from ileal neuroendocrine tumors.

    Science.gov (United States)

    Calissendorff, Jan; Sundin, Anders; Falhammar, Henrik

    2014-09-01

    Metastases from ileal neuroendocrine tumors (NETs) to the myocardium are rare and generally seen in patients with widespread metastatic NET disease. The objectives of this investigation were to describe the frequency of intracardiac metastases in ileal NET patients examined by (68)Ga-DOTA-TOC-PET/CT and to describe the cases in detail. All (68)Ga-DOTA-TOC-PET/CT examinations performed at the Karolinska University Hospital since 2010 until April 2012 were reviewed. In all, 128 out of 337 examinations were in patients with ileal NETs. Four patients had seven myocardiac metastases, yielding a frequency of 4.3 % in patients with ileal NETs. One patient had cardiac surgery while three were treated with somatostatin analogs. The cardiac metastases did not affect the patients' activity of daily life. (68)Ga-DOTA-TOC-PET/CT is an established imaging modality in identifying cardiac metastases in ileal NETs. Prospective studies are needed to confirm the true clinical value of (68)Ga-DOTA-TOC-PET/CT in detecting cardiac metastases in both ileal and non-ileal NETs.

  19. Feasibility of breathing-adapted PET/CT imaging for radiation therapy of Hodgkin lymphoma

    DEFF Research Database (Denmark)

    Aznar, M C; Andersen, Flemming; Berthelsen, A K

    2011-01-01

    Aim: Respiration can induce artifacts in positron emission tomography (PET)/computed tomography (CT) images leading to uncertainties in tumour volume, location and uptake quantification. Respiratory gating for PET images is now established but is not directly translatable to a radiotherapy setup....... in PET/CT images. These results suggest that advanced therapies (such as SUV-based dose painting) will likely require breathing-adapted PET images and that the relevant SUV thresholds are yet to be investigated....

  20. ECG-triggered {sup 18}F-fluorodeoxyglucose positron emission tomography imaging of the rat heart is dramatically enhanced by acipimox

    Energy Technology Data Exchange (ETDEWEB)

    Poussier, Sylvain [Experimental Imaging Platform, Nancyclotep, Nancy (France); CHU-Nancy, Department of Nuclear Medicine, Nancy (France); Nancy University, Faculty of Medicine, Nancy (France); Hopital de Brabois, Nancyclotep, Service de Medecine Nucleaire, Vandoeuvre-les-Nancy (France); Maskali, Fatiha [Experimental Imaging Platform, Nancyclotep, Nancy (France); CHU-Nancy, Department of Nuclear Medicine, Nancy (France); Tran, Nguyen [Nancy University, Faculty of Medicine, Nancy (France); Surgery School, Faculty of Medicine, Nancy (France); INSERM U961, Nancy (France); Person, Christophe; Boutley, Henri; Karcher, Gilles [Experimental Imaging Platform, Nancyclotep, Nancy (France); CHU-Nancy, Department of Nuclear Medicine, Nancy (France); Nancy University, Faculty of Medicine, Nancy (France); Maureira, Pablo [Nancy University, Faculty of Medicine, Nancy (France); Surgery School, Faculty of Medicine, Nancy (France); CHU-Nancy, Department of Cardiac Surgery, Nancy (France); Lacolley, Patrick; Regnault, Veronique [Nancy University, Faculty of Medicine, Nancy (France); INSERM U961, Nancy (France); Fay, Renaud [Centre d' Investigation Clinique, INSERM, U9501, Nancy (France); Marie, Pierre Yves [Experimental Imaging Platform, Nancyclotep, Nancy (France); CHU-Nancy, Department of Nuclear Medicine, Nancy (France); Nancy University, Faculty of Medicine, Nancy (France); INSERM U961, Nancy (France)

    2010-09-15

    {sup 18}F-Fluorodeoxyglucose (FDG) imaging, provided by current positron emission tomography (PET) systems dedicated to small animals, might provide a precise functional assessment of the left ventricle (LV) in rats, although conventional metabolic conditioning by hyperinsulinaemic glucose clamping is not well adapted to this setting. This study was aimed at assessing cardiac FDG PET in rats pre-medicated with acipimox, a potent nicotinic acid derivative yielding comparable image quality to clamping in man. Metabolic conditioning was compared in Wistar rats between a conventional oral glucose loading (1.5 mg/kg) and acipimox, which was given at high but well tolerated doses subcutaneously (25 mg/kg) or orally (50 mg/kg). Myocardial to blood (M/B) activity ratio and myocardial signal to noise (S/N) ratio were analysed on gated FDG PET images. The S/N ratio of the gated cardiac images evolved in parallel with the M/B activity ratio and these two ratios were independently enhanced by glucose loading and acipimox. However, these enhancements were: (1) dramatic for acipimox, especially for the high oral dose of 50 mg/kg (from 2.85 {+-} 0.57 to 10.73 {+-} 0.54 for the M/B ratio of rats with or without glucose loading; p < 0.0001) and (2) much more limited for glucose loading (from 6.61 {+-} 0.49 to 7.89 {+-} 0.41 for the M/B ratio of rats with or without acipimox administration; p = 0.049). With the high oral dose of acipimox, the gated cardiac FDG PET images had very high S/N ratios, at least equivalent to those currently documented in man. Metabolic conditioning by oral doses of acipimox is highly efficient for experimental studies planned with cardiac FDG PET in rats. (orig.)

  1. The usefulness of treatment evaluation of severe heart failure by ECG-gated myocardial SPECT

    International Nuclear Information System (INIS)

    Ohkoshi, Nobuyuki; Watanabe, Shingo; Matsumoto, Tooru

    2011-01-01

    Our purpose of study was to investigate the usefulness of treatment evaluation of severe heart failure by Electrocardiogram (ECG)-gated myocardial single photon emission computed tomography (SPECT). We evaluated the cardiac function in the case of severe heart failure by gated SPECT and compared it with the cardiac function obtained by left ventriculography (LVG), echocardiography, cardiac MRI, and B-type natriuretic peptide (BNP) values. We investigated the correlation of ejection fraction (EF), time lag of wall motion between the septal and lateral walls of the left ventricle for cardiac resynchronization therapy (CRT) and wall thickening (WT). We classified the left ventricular (LV) into basal, middle and apical areas for comparison of WT. We investigated the effect of a perfusion defect score in these comparisons. The gated SPECT results were correlated with comparative subjects in EF. The results were correlated with MRI on the middle area of the LV in the comparison of WT. We thought it was possible that there was an effect from a perfusion defect score in a time lag comparison of wall motion. Treatment evaluation of severe heart failure by gated SPECT is useful, because it is able to obtain three-dimensional cardiac function analysis, and it offers objectivity and reproducible quantitative evaluation. At the same time, perfusion SPECT is helpful for CRT and LV-plasty. (author)

  2. Validation of a non-invasive arterial monitor GATE model for PET

    Energy Technology Data Exchange (ETDEWEB)

    Giansiracusa, P.J., E-mail: pgia@student.unimelb.edu.au [School of Physics, The University of Melbourne, Parkville (Australia); Peake, D.J. [DETECT Australia, Bundoora (Australia); Sobott, B.A. [School of Physics, The University of Melbourne, Parkville (Australia); O' Keefe, G. [The Austin PET Centre, Austin Hospital, Heidelberg (Australia); Rassool, R.P. [School of Physics, The University of Melbourne, Parkville (Australia)

    2014-02-11

    The Non-Invasive Arterial Monitor (NIAM3) is an SiPM based detector system designed for calibrating Positron-Emission Tomography (PET) images without invasive blood sampling. By imaging the radial and ulnar arteries in the wrist directly with a custom built PET system the resultant PET images can be calibrated. An integral step in the development of a complex detector system is the creation of a model which accurately reflects the physical reality being studied. This paper describes the development of a simulation for NIAM which shows good agreement between the model and physical detector setup.

  3. USPIO-enhanced 3D-cine self-gated cardiac MRI based on a stack-of-stars golden angle short echo time sequence: Application on mice with acute myocardial infarction.

    Science.gov (United States)

    Trotier, Aurélien J; Castets, Charles R; Lefrançois, William; Ribot, Emeline J; Franconi, Jean-Michel; Thiaudière, Eric; Miraux, Sylvain

    2016-08-01

    To develop and assess a 3D-cine self-gated method for cardiac imaging of murine models. A 3D stack-of-stars (SOS) short echo time (STE) sequence with a navigator echo was performed at 7T on healthy mice (n = 4) and mice with acute myocardial infarction (MI) (n = 4) injected with ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles. In all, 402 spokes were acquired per stack with the incremental or the golden angle method using an angle increment of (360/402)° or 222.48°, respectively. A cylindrical k-space was filled and repeated with a maximum number of repetitions (NR) of 10. 3D cine cardiac images at 156 μm resolution were reconstructed retrospectively and compared for the two methods in terms of contrast-to-noise ratio (CNR). The golden angle images were also reconstructed with NR = 10, 6, and 3, to assess cardiac functional parameters (ejection fraction, EF) on both animal models. The combination of 3D SOS-STE and USPIO injection allowed us to optimize the identification of cardiac peaks on navigator signal and generate high CNR between blood and myocardium (15.3 ± 1.0). The golden angle method resulted in a more homogeneous distribution of the spokes inside a stack (P cine images could be obtained without electrocardiogram or respiratory gating in mice. It allows precise measurement of cardiac functional parameters even on MI mice. J. Magn. Reson. Imaging 2016;44:355-365. © 2016 Wiley Periodicals, Inc.

  4. Amplitude-based optimal respiratory gating in positron emission tomography in patients with primary lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Grootjans, Willem; Meeuwis, Antoi P.W.; Vos, Charlotte S. van der; Gotthardt, Martin; Oyen, Wim J.G.; Visser, Eric P. [Radboud University Medical Center, Department of Radiology and Nuclear Medicine, P.O. Box 9101, Nijmegen (Netherlands); Geus-Oei, Lioe-Fee de [Radboud University Medical Center, Department of Radiology and Nuclear Medicine, P.O. Box 9101, Nijmegen (Netherlands); University of Twente, MIRA Institute for Biomedical Technology and Technical Medicine, Enschede (Netherlands)

    2014-12-15

    Respiratory motion during PET imaging introduces quantitative and diagnostic inaccuracies, which may result in non-optimal patient management. This study investigated the effects of respiratory gating on image quantification using an amplitude-based optimal respiratory gating (ORG) algorithm. Whole body FDG-PET/CT was performed in 66 lung cancer patients. The respiratory signal was obtained using a pressure sensor integrated in an elastic belt placed around the patient's thorax. ORG images were reconstructed with 50 %, 35 %, and 20 % of acquired PET data (duty cycle). Lesions were grouped into anatomical locations. Differences in lesion volume between ORG and non-gated images, and mean FDG-uptake (SUV{sub mean}) were calculated. Lesions in the middle and lower lobes demonstrated a significant SUV{sub mean} increase for all duty cycles and volume decrease for duty cycles of 35 % and 20 %. Significant increase in SUV{sub mean} and decrease in volume for lesions in the upper lobes were observed for a 20 % duty cycle. The SUV{sub mean} increase for central lesions was significant for all duty cycles, whereas a significant volume decrease was observed for a duty cycle of 20 %. This study implies that ORG could influence clinical PET imaging with respect to response monitoring and radiotherapy planning. (orig.)

  5. Development of PET/MRI with insertable PET for simultaneous PET and MR imaging of human brain

    International Nuclear Information System (INIS)

    Jung, Jin Ho; Choi, Yong; Jung, Jiwoong; Kim, Sangsu; Lim, Hyun Keong; Im, Ki Chun; Oh, Chang Hyun; Park, Hyun-wook; Kim, Kyung Min; Kim, Jong Guk

    2015-01-01

    Purpose: The purpose of this study was to develop a dual-modality positron emission tomography (PET)/magnetic resonance imaging (MRI) with insertable PET for simultaneous PET and MR imaging of the human brain. Methods: The PET detector block was composed of a 4 × 4 matrix of detector modules, each consisting of a 4 × 4 array LYSO coupled to a 4 × 4 Geiger-mode avalanche photodiode (GAPD) array. The PET insert consisted of 18 detector blocks, circularly mounted on a custom-made plastic base to form a ring with an inner diameter of 390 mm and axial length of 60 mm. The PET gantry was shielded with gold-plated conductive fabric tapes with a thickness of 0.1 mm. The charge signals of PET detector transferred via 4 m long flat cables were fed into the position decoder circuit. The flat cables were shielded with a mesh-type aluminum sheet with a thickness of 0.24 mm. The position decoder circuit and field programmable gate array-embedded DAQ modules were enclosed in an aluminum box with a thickness of 10 mm and located at the rear of the MR bore inside the MRI room. A 3-T human MRI system with a Larmor frequency of 123.7 MHz and inner bore diameter of 60 cm was used as the PET/MRI hybrid system. A custom-made radio frequency (RF) coil with an inner diameter of 25 cm was fabricated. The PET was positioned between gradient and the RF coils. PET performance was measured outside and inside the MRI scanner using echo planar imaging, spin echo, turbo spin echo, and gradient echo sequences. MRI performance was also evaluated with and without the PET insert. The stability of the newly developed PET insert was evaluated and simultaneous PET and MR images of a brain phantom were acquired. Results: No significant degradation of the PET performance caused by MR was observed when the PET was operated using various MR imaging sequences. The signal-to-noise ratio of MR images was slightly degraded due to the PET insert installed inside the MR bore while the homogeneity was

  6. Development of PET/MRI with insertable PET for simultaneous PET and MR imaging of human brain

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Jin Ho; Choi, Yong, E-mail: ychoi.image@gmail.com; Jung, Jiwoong; Kim, Sangsu; Lim, Hyun Keong; Im, Ki Chun [Department of Electronic Engineering, Sogang University, 35 Baekbeom-ro, Mapo-gu, Seoul 121-742 (Korea, Republic of); Oh, Chang Hyun; Park, Hyun-wook [Department of Electrical Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Kim, Kyung Min; Kim, Jong Guk [Korea Institute of Radiological and Medical Science, 75 Nowon-ro, Nowon-gu, Seoul 139-709 (Korea, Republic of)

    2015-05-15

    Purpose: The purpose of this study was to develop a dual-modality positron emission tomography (PET)/magnetic resonance imaging (MRI) with insertable PET for simultaneous PET and MR imaging of the human brain. Methods: The PET detector block was composed of a 4 × 4 matrix of detector modules, each consisting of a 4 × 4 array LYSO coupled to a 4 × 4 Geiger-mode avalanche photodiode (GAPD) array. The PET insert consisted of 18 detector blocks, circularly mounted on a custom-made plastic base to form a ring with an inner diameter of 390 mm and axial length of 60 mm. The PET gantry was shielded with gold-plated conductive fabric tapes with a thickness of 0.1 mm. The charge signals of PET detector transferred via 4 m long flat cables were fed into the position decoder circuit. The flat cables were shielded with a mesh-type aluminum sheet with a thickness of 0.24 mm. The position decoder circuit and field programmable gate array-embedded DAQ modules were enclosed in an aluminum box with a thickness of 10 mm and located at the rear of the MR bore inside the MRI room. A 3-T human MRI system with a Larmor frequency of 123.7 MHz and inner bore diameter of 60 cm was used as the PET/MRI hybrid system. A custom-made radio frequency (RF) coil with an inner diameter of 25 cm was fabricated. The PET was positioned between gradient and the RF coils. PET performance was measured outside and inside the MRI scanner using echo planar imaging, spin echo, turbo spin echo, and gradient echo sequences. MRI performance was also evaluated with and without the PET insert. The stability of the newly developed PET insert was evaluated and simultaneous PET and MR images of a brain phantom were acquired. Results: No significant degradation of the PET performance caused by MR was observed when the PET was operated using various MR imaging sequences. The signal-to-noise ratio of MR images was slightly degraded due to the PET insert installed inside the MR bore while the homogeneity was

  7. A technique of using gated-CT images to determine internal target volume (ITV) for fractionated stereotactic lung radiotherapy

    International Nuclear Information System (INIS)

    Jin Jianyue; Ajlouni, Munther; Chen Qing; Yin, Fang-Fang; Movsas, Benjamin

    2006-01-01

    Background and purpose: To develop and evaluate a technique and procedure of using gated-CT images in combination with PET image to determine the internal target volume (ITV), which could reduce the planning target volume (PTV) with adequate target coverage. Patients and methods: A skin marker-based gating system connected to a regular single slice CT scanner was used for this study. A motion phantom with adjustable motion amplitude was used to evaluate the CT gating system. Specifically, objects of various sizes/shapes, considered as virtual tumors, were placed on the phantom to evaluate the number of phases of gated images required to determine the ITV while taking into account tumor size, shape and motion. A procedure of using gated-CT and PET images to define ITV for patients was developed and was tested in patients enrolled in an IRB approved protocol. Results: The CT gating system was capable of removing motion artifacts for target motion as large as 3-cm when it was gated at optimal phases. A phantom study showed that two gated-CT scans at the end of expiration and the end of inspiration would be sufficient to determine the ITV for tumor motion less than 1-cm, and another mid-phase scan would be required for tumors with 2-cm motion, especially for small tumors. For patients, the ITV encompassing visible tumors in all sets of gated-CT and regular spiral CT images seemed to be consistent with the target volume determined from PET images. PTV expanded from the ITV with a setup uncertainty margin had less volume than PTVs from spiral CT images with a 10-mm generalized margin or an individualized margin determined at fluoroscopy. Conclusions: A technique of determining the ITV using gated-CT images was developed and was clinically implemented successfully for fractionated stereotactic lung radiotherapy

  8. Feasibility of breathing-adapted PET/CT imaging for radiation therapy of Hodgkin lymphoma

    DEFF Research Database (Denmark)

    Aznar, M C; Andersen, Flemming; Berthelsen, A K

    2011-01-01

    Aim: Respiration can induce artifacts in positron emission tomography (PET)/computed tomography (CT) images leading to uncertainties in tumour volume, location and uptake quantification. Respiratory gating for PET images is now established but is not directly translatable to a radiotherapy setup....... uptake in PET/CT images. These results suggest that advanced therapies (such as SUV-based dose painting) will likely require breathing-adapted PET images and that the relevant SUV thresholds are yet to be investigated....

  9. Development of PET in Latin America. Experience of the first PET-Cyclotron Center

    International Nuclear Information System (INIS)

    Tutor, C.A.; Frias, L.

    2002-01-01

    Aim: Describe the experience of the first PET-Cyclotron Center in Latin America. Demonstrate the viability of running a PET Center in Argentina despite the economic crisis. Materials and Methods: For this study, we used a UGM/GE Quest 250 PET scan, a RDS 112 cyclotron and a Radiosynthesis Laboratory installed at the (FUESMEN) Nuclear Medicine School Foundation, located in Mendoza City, in the middle-west of Argentina. From January 1999 to March 2002, 741 studies were obtained, 731 were 18 FluorDeoxyGlucose-PET studies and 10 phantoms for calibration purposes. We used acquisition and imaging processing standard protocols, as well as research protocols designed according to the pathology under investigation. To better correlate anatomical and functional images, we used fusion techniques with (CT) Computed Tomography in some (WB) whole-body PET scans. Results: A total of 731 patients were retrospectively analyzed and classified according to statistics variables such as: 1-sex: 317 women and 414 men, 2-type of scan: 439 WB cases, 267 brain studies and 25 cardiac. From this data we divided them as PET indications and resulted in 17 cases as healthy volunteers, 422 oncological cases, 267 neurological studies and 25 cardiac for myocardial viability. According to the origin they were classified as patients coming from Mendoza 544, Buenos Aires 112, other argentine provinces 60 and foreign (Chile, Brazil and Uruguay) 15 cases. In terms of billing, 181 studies were done free of charge, 95 under research protocols were also done free of charge and 451 were charged. Conclusion: Not only the economical and political factors play an important role limiting the advances of PET Imaging in Latin America, but also the lack of a neighboring cyclotron that circumscribe many hospitals to have access to the radiopharmaceutical agent. FUESMEN was established in 1991 by three governmental entities: the (CONEA) National Commission of Atomic Energy, the (UNC) National University of Cuyo and

  10. Technique for producing cardiac radionuclide motion images

    International Nuclear Information System (INIS)

    Reese, I.C.; Mishkin, F.S.

    1975-01-01

    Sequential frames of different portions of the cardiac cycle are gated into a minicomputer by using an EKG signal recorded onto digital tape simultaneously with imaging information. Serial display of these frames on the computer oscilloscope or projection of 35-mm half frames of these images provides a cardiac motion image with information content adequate for qualitatively assessing cardiac motion. (U.S.)

  11. Respiratory-Gated Positron Emission Tomography and Breath-Hold Computed Tomography Coupling to Reduce the Influence of Respiratory Motion: Methodology and Feasibility

    International Nuclear Information System (INIS)

    Daouk, J.; Fin, L.; Bailly, P.; Meyer, M.E.

    2009-01-01

    Background: Respiratory motion causes uptake in positron emission tomography (PET) images of chest and abdominal structures to be blurred and reduced in intensity. Purpose: To compare two respiratory-gated PET binning methods (based on frequency and amplitude analyses of the respiratory signal) and to propose a 'BH-based' method based on an additional breath-hold computed tomography (CT) acquisition. Material and Methods: Respiratory-gated PET consists in list-mode (LM) acquisition with simultaneous respiratory signal recording. A phantom study featured rectilinear movement of a 0.5-ml sphere filled with 18 F-fluorodeoxyglucose ( 18 F-FDG) solution, placed in a radioactive background (sphere-to-background contrast 6:1). Two patients were also examined. Three figures of merit were calculated: the target-to-background ratio profile (TBRP) in the axial direction through the uptake (i.e., the sphere or lesion), full-width-at-half-maximum (FWHM) values, and maximized standard uptake values (SUVmax). Results: In the phantom study, the peak TBRP was 0.9 for non-gated volume, 1.83 for BH-based volume, and varied between 1.13 and 1.73 for Freq-based volumes and between 1.34 and 1.66 for Amp-based volumes. A reference volume (REF-static) was also acquired for the phantom (in a static, 'expiratory' state), with a peak TBRP at 1.88. TBRPs were computed for patient data, with higher peak values for all gated volumes than for non-gated volumes. Conclusion: Respiratory-gated PET acquisition reduces the blurring effect and increases image contrast. However, Freq-based and Amp-based volumes are still influenced by inappropriate attenuation correction and misregistration of mobile lesions on CT images. The proposed BH-based method both reduces motion artifacts and improves PET-CT registration

  12. Measurement of ventricular function by ECG gating during atrial fibrillation

    International Nuclear Information System (INIS)

    Bacharach, S.L.; Green, M.V.; Bonow, R.O.; Findley, S.L.; Ostrow, H.G.; Johnston, G.S.

    1981-01-01

    The assumptions necessary to perform ECG-gated cardiac studies are seemingly not valid for patients in atrial fibrillation (AF). To evaluate the effect of AF on equilibrium gated scintigraphy, beat-by-beat measurements of left-ventricular function were made on seven subjects in AF (mean heart rate 64 bpm), using a high-efficiency nonimaging detector. The parameters evaluated were ejection fraction (EF), time to end-systole (TES), peak rates of ejection and filling (PER,PFR), and their times of occurrence (TPER, TPFR). By averaging together single-beat values of EF, PER, etc., it was possible to determine the true mean values of these parameters. The single-beam mean values were compared with the corresponding parameters calculated from one ECG-gated time-activity curve (TAC) obtained by superimposing all the single-beat TACs irrespective of their length. For this population with slow heart rates, we find that the values for EF, etc., produced from ECG-gated time-activity curves, are very similar to those obtained from the single-beat data. Thus use of ECG gating at low heart rates may allow reliable estimation of average cardiac function even in subjects with AF

  13. Sodium Channel (Dys)Function and Cardiac Arrhythmias

    NARCIS (Netherlands)

    Remme, Carol Ann; Bezzina, Connie R.

    2010-01-01

    P>Cardiac voltage-gated sodium channels are transmembrane proteins located in the cell membrane of cardiomyocytes. Influx of sodium ions through these ion channels is responsible for the initial fast upstroke of the cardiac action potential. This inward sodium current thus triggers the initiation

  14. Multiaxial tomography of heart chambers by gated blood-pool emission computed tomography using a rotating gamma camera

    International Nuclear Information System (INIS)

    Tamaki, N.; Mukai, T.; Ishii, Y.; Yonekura, Y.; Yamamoto, K.; Kadota, K.; Kambara, H.; Kawai, C.; Torizuka, K.

    1983-01-01

    Fifteen patients and three volunteers underwent radionuclide blood-pool cardiac studies with electrocardiographic gating. Following conventional planar-gated imaging (anterior and left anterior oblique projections), emission computed tomography (ECT), using a rotating gamma camera, was performed.A series of transaxial tomograms of the cardiac chambers was obtained. The left ventricular short-axis plane, long-axis plane, and four-chamber-view plane were then reorganized; each chamber was visualized separately. Compared to gated planar imaging, this technique showed regional asynergy more clearly in patients with myocardial infarction and demonstrated dilatation of the atria and ventricles more accurately in patients with an atrial septal defect and valvular heart diseases. In addition, when a section of the heart is otained at any angle with gated blood pool ECT, three-dimensional assessment of cardiac chambers in motion is more precise; mutual superimposition becomes unnecessary

  15. Normal value of functional parameters in gated myocardial perfusion SPECT in patients with low risk of coronary artery disease: emory cardiac tool box program

    Energy Technology Data Exchange (ETDEWEB)

    Kang, D. Y.; Kim, M. H.; Kim, Y. D.; Kim, D. K. [Donga University College of Medicine, Busan (Korea, Republic of)

    2002-07-01

    Absolute value of the functional data of gated myocardial perfusion SPECT is necessary to determine that individual patient is normal or not. Tc-99m MIBI gated myocardial perfusion SPECT was performed using emory cardiac tool box program. All patients (M:F=15:36, age 64{+-}10 yrs) showed normal myocardial perfusion. The patients with following characteristics were excluded; previous angina or MI, ECG change with Q wave or ST-T change, diabetes mellitus, hypercholesterolemia, typical chest pain and hypertension. In all patients, myocardial mass is 117{+-}23 g in stress gated SPECT, 106{+-}22 g in stress ungated SPECT and 102{+-}21 g in rest ungated SPECT. EDV is 90{+-}28 ml, ESV 26{+-}20 ml, SV 66{+-}21 ml, EF 73{+-}10 % and TID 1.06{+-}0.14. Myocardial mass in rest ungated SPECT is significantly different between men and women (p=0.025). Myocardial mass is significantly different between stress gated SPECT and stress ungated SPECT (p=0.000), and between stress ungated SPECT and rest ungated SPECT (p=0.003). We provide normal value of functional parameters to determine the abnormality of individual patients in patients with low risk of coronary artery disease.

  16. The diagnosis of anthracycline-induced cardiac damage and heart failure

    Directory of Open Access Journals (Sweden)

    Jarosław Dudka

    2009-05-01

    Full Text Available Routine examinations during chemotherapy containing anthracyclines evaluate heart function before treatment and monitor cardiotoxic effects during and after therapy. A number of methods are useful in cardiac assessment, including electrocardiography, radiology techniques (RTG, CT, MRI, PET-CT, PET-MRI, echocardiography, radioisotope imaging techniques (scyntygraphy, MUGA, PET, and ultra-structure evaluation in biopsy samples. Nevertheless, there is a continuous need for new methods to predict future damage at the initial stages of cardiac changes. In recent years the therapeutic usefulness of biochemical blood parameters in anthracycline-treated patients has been assessed. The levels of cardiac troponines (cTnI, cTnT, natriuretic peptides (ANP, BNP, and endothelin 1 have been included in the studies. Heart-type fatty acid binding protein (H-FABP is another promising factor showing cardiomyocytic impairment. However, the clinical use of biochemical parameters in diagnosing anthracycline-related cardiotoxicity is still a controversial issue.

  17. Functional cardiac imaging: positron emission tomography

    International Nuclear Information System (INIS)

    Mullani, N.A.; Gould, K.L.

    1984-01-01

    Dynamic cardiovascular imaging plays a vital role in the diagnosis and treatment of cardiac disease by providing information about the function of the heart. During the past 30 years, cardiovascular imaging has evolved from the simple chest x-ray and fluoroscopy to such sophisticated techniques as invasive cardiac angiography and cinearteriography and, more recently, to noninvasive cardiac CT scanning, nuclear magnetic resonance, and positron emission tomography, which reflect more complex physiologic functions. As research tools, CT, NMR, and PET provide quantitative information on global as well as regional ventricular function, coronary artery stenosis, myocardial perfusion, glucose and fatty acid metabolism, or oxygen utilization, with little discomfort or risk to the patient. As imaging modalities become more sophisticated and more oriented toward clinical application, the prospect of routinely obtaining such functional information about the heart is becoming realistic. However, these advances are double-edged in that the interpretation of functional data is more complex than that of the anatomic imaging familiar to most physicians. They will require an enhanced understanding of the physiologic and biochemical processes, as well as of the instrumentation and techniques for analyzing the data. Of the new imaging modalities that provide functional information about the heart, PET is the most useful because it quantitates the regional distribution of radionuclides in vivo. Clinical applications, interpretation of data, and the impact of PET on our understanding of cardiac pathophysiology are discussed. 5 figures

  18. A model of cardiac ryanodine receptor gating predicts experimental Ca2+-dynamics and Ca2+-triggered arrhythmia in the long QT syndrome

    Science.gov (United States)

    Wilson, Dan; Ermentrout, Bard; Němec, Jan; Salama, Guy

    2017-09-01

    Abnormal Ca2+ handling is well-established as the trigger of cardiac arrhythmia in catecholaminergic polymorphic ventricular tachycardia and digoxin toxicity, but its role remains controversial in Torsade de Pointes (TdP), the arrhythmia associated with the long QT syndrome (LQTS). Recent experimental results show that early afterdepolarizations (EADs) that initiate TdP are caused by spontaneous (non-voltage-triggered) Ca2+ release from Ca2+-overloaded sarcoplasmic reticulum (SR) rather than the activation of the L-type Ca2+-channel window current. In bradycardia and long QT type 2 (LQT2), a second, non-voltage triggered cytosolic Ca2+ elevation increases gradually in amplitude, occurs before overt voltage instability, and then precedes the rise of EADs. Here, we used a modified Shannon-Puglisi-Bers model of rabbit ventricular myocytes to reproduce experimental Ca2+ dynamics in bradycardia and LQT2. Abnormal systolic Ca2+-oscillations and EADs caused by SR Ca2+-release are reproduced in a modified 0-dimensional model, where 3 gates in series control the ryanodine receptor (RyR2) conductance. Two gates control RyR2 activation and inactivation and sense cytosolic Ca2+ while a third gate senses luminal junctional SR Ca2+. The model predicts EADs in bradycardia and low extracellular [K+] and cessation of SR Ca2+-release terminate salvos of EADs. Ca2+-waves, systolic cell-synchronous Ca2+-release, and multifocal diastolic Ca2+ release seen in subcellular Ca2+-mapping experiments are observed in the 2-dimensional version of the model. These results support the role of SR Ca2+-overload, abnormal SR Ca2+-release, and the subsequent activation of the electrogenic Na+/Ca2+-exchanger as the mechanism of TdP. The model offers new insights into the genesis of cardiac arrhythmia and new therapeutic strategies.

  19. PET/CT cardiology: an area whose boundaries are still out of sight

    Energy Technology Data Exchange (ETDEWEB)

    Lucignani, Giovanni [University of Milan and Unit of Molecular Imaging, Institute of Radiological Sciences, Division of Radiation Therapy, European Institute of Oncology, Milan (Italy)

    2006-05-15

    Positron emission tomography (PET) and X-ray computed tomography (CT) performed with PET/CT cameras allow us to obtain concurrently information on the presence and degree of alterations of myocardial perfusion and metabolism and on coronary arteries calcification. Furthermore, by gated myocardial perfusion studies, PET may provide crucial information on regional coronary blood flow reserve and endothelial dysfunction. A number of recent papers provide some insight on the potential of PET/CT in cardiology and in the assessment of various cardiovascular diseases including various types of vasculitis and metabolic diseases.

  20. Non rigid respiratory motion correction in whole body PET/MR imaging

    International Nuclear Information System (INIS)

    Fayad, Hadi; Schmidt, Holger; Wuerslin, Christian; Visvikis, Dimitris

    2014-01-01

    Respiratory motion in PET/MR imaging leads to reduced quantitative and qualitative image accuracy. Correction methodologies include the use of respiratory synchronized gated frames which lead to low signal to noise ratio (SNR) given that each frame contains only part of the count available throughout an average PET acquisition. In this work, 4D MRI extracted elastic transformations were applied to list-mode data either inside the image reconstruction or to the reconstructed respiratory synchronized images to obtain respiration corrected PET images.

  1. Paradoxical motion of interventricular septum on Tc-99m MIBI gated SPECT study

    International Nuclear Information System (INIS)

    Ergun, E.L.; Erbas, B.; Beylergil, V.; Demirturk, O.S.; Pasaoglu, I.

    2004-01-01

    After uncomplicated cardiac surgery, abnormal motion of the interventricular septum is frequently observed. The interventricular septum has often been found to display dyskinetic, or paradoxical motion by echocardiographic studies. This study was undertaken to describe instances of paradoxical motion of interventricular septum on Tc-99m MIBI gated SPECT studies in patients after coronary artery by pass graft surgery. Tc-99m MIBI gated SPECT in conjunction with stress myocardial perfusion SPECT was performed in 18 patients who had history of cardiac bypass graft surgery. Paradoxical motion of the interventricular septum was defined visually from Tc-99m MIBI gated SPECT. Perfusion of the interventricular septum was examined from myocardial perfusion images in the same study. Paradoxical motion of the interventricular septum was observed in 4 patients (22%). The interventricular septum was normally perfused in all patients. It was concluded that paradoxical motion of the interventricular septum in patients who had a history of cardiac by-pass graft surgery is not an uncommon finding and it can be observed with gated SPECT. The exact mechanism of this phenomenon is not well-known. A normal perfusion in interventricular wall helps to discriminate this situation from a real abnormality. (author)

  2. Correcting for respiratory motion in liver PET/MRI: preliminary evaluation of the utility of bellows and navigated hepatobiliary phase imaging

    International Nuclear Information System (INIS)

    Hope, Thomas A.; Verdin, Emily F.; Bergsland, Emily K.; Ohliger, Michael A.; Corvera, Carlos University; Nakakura, Eric K.

    2015-01-01

    The purpose of this study was to evaluate the utility of bellows-based respiratory compensation and navigated hepatobiliary phase imaging to correct for respiratory motion in the setting of dedicated liver PET/MRI. Institutional review board approval and informed consent were obtained. Six patients with metastatic neuroendocrine tumor were imaged using Ga-68 DOTA-TOC PET/MRI. Whole body imaging and a dedicated 15-min liver PET acquisition was performed, in addition to navigated and breath-held hepatobiliary phase (HBP) MRI. Liver PET data was reconstructed three ways: the entire data set (liver PET), gated using respiratory bellows (RC-liver PET), and a non-gated data set reconstructed using the same amount of data used in the RC-liver PET (shortened liver PET). Liver lesions were evaluated using SUV max , SUV peak , SUV mean , and Vol isocontour . Additionally, the displacement of each lesion between the RC-liver PET images and the navigated and breath-held HBP images was calculated. Respiratory compensation resulted in a 43 % increase in SUVs compared to ungated data (liver vs RC-liver PET SUV max 26.0 vs 37.3, p < 0.001) and a 25 % increase compared to a non-gated reconstruction using the same amount of data (RC-liver vs shortened liver PET SUV max 26.0 vs 32.6, p < 0.001). Lesion displacement was minimized using navigated HBP MRI (1.3 ± 1.0 mm) compared to breath-held HBP MRI (23.3 ± 1.0 mm). Respiratory bellows can provide accurate respiratory compensation when imaging liver lesions using PET/MRI, and results in increased SUVs due to a combination of increased image noise and reduced respiratory blurring. Additionally, navigated HBP MRI accurately aligns with respiratory compensated PET data.

  3. Correcting for respiratory motion in liver PET/MRI: preliminary evaluation of the utility of bellows and navigated hepatobiliary phase imaging

    Energy Technology Data Exchange (ETDEWEB)

    Hope, Thomas A. [Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA (United States); Department of Radiology, San Francisco VA Medical Center, San Francisco, CA (United States); Verdin, Emily F. [Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA (United States); Bergsland, Emily K. [Division of Hematology/Oncology, Department of Medicine, University of California, San Francisco, San Francisco, CA (United States); Ohliger, Michael A. [Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA (United States); Department of Radiology, San Francisco General Hospital, San Francisco, CA (United States); Corvera, Carlos University; Nakakura, Eric K. [Division of Surgical Oncology, Department of Surgery, University of California, San Francisco, San Francisco, CA (United States)

    2015-09-18

    The purpose of this study was to evaluate the utility of bellows-based respiratory compensation and navigated hepatobiliary phase imaging to correct for respiratory motion in the setting of dedicated liver PET/MRI. Institutional review board approval and informed consent were obtained. Six patients with metastatic neuroendocrine tumor were imaged using Ga-68 DOTA-TOC PET/MRI. Whole body imaging and a dedicated 15-min liver PET acquisition was performed, in addition to navigated and breath-held hepatobiliary phase (HBP) MRI. Liver PET data was reconstructed three ways: the entire data set (liver PET), gated using respiratory bellows (RC-liver PET), and a non-gated data set reconstructed using the same amount of data used in the RC-liver PET (shortened liver PET). Liver lesions were evaluated using SUV{sub max}, SUV{sub peak}, SUV{sub mean}, and Vol{sub isocontour}. Additionally, the displacement of each lesion between the RC-liver PET images and the navigated and breath-held HBP images was calculated. Respiratory compensation resulted in a 43 % increase in SUVs compared to ungated data (liver vs RC-liver PET SUV{sub max} 26.0 vs 37.3, p < 0.001) and a 25 % increase compared to a non-gated reconstruction using the same amount of data (RC-liver vs shortened liver PET SUV{sub max} 26.0 vs 32.6, p < 0.001). Lesion displacement was minimized using navigated HBP MRI (1.3 ± 1.0 mm) compared to breath-held HBP MRI (23.3 ± 1.0 mm). Respiratory bellows can provide accurate respiratory compensation when imaging liver lesions using PET/MRI, and results in increased SUVs due to a combination of increased image noise and reduced respiratory blurring. Additionally, navigated HBP MRI accurately aligns with respiratory compensated PET data.

  4. Cardiac MR imaging: Comparison with echocardiography and dynamic CT

    International Nuclear Information System (INIS)

    Colletti, P.M.; Norris, S.; Raval, J.; Boswell, W.; Lee, K.; Ralls, P.; Haywood, J.; Halls, J.

    1986-01-01

    The authors compared gated cardiac MR imaging with two-dimensional and Doppler echocardiography and dynamic CT. Gated cardiac MR imaging (VISTA unit, 0.5 T) was performed in 55 patients with a variety of conditions. Accuracy of diagnosis was compared. CT showed arterial, valvular, and pericardial calcifications not seen on MR imaging. Many lesions were seen as well on CT as on MR imaging. Two-dimensional echocardiography was superior in demonstrating wall motion and valvular disease. MR imaging was superior in demonstrating myocardial structures

  5. Volume and planar gated cardiac magnetic resonance imaging: a correlative study of normal anatomy with Thallium-201 SPECT and cadaver sections

    International Nuclear Information System (INIS)

    Go, R.T.; MacIntyre, W.J.; Yeung, H.N.

    1984-01-01

    Magnetic resonance (MR) gated cardiac imaging was performed in ten subjects using a prototype 0.15-T resistive magnet imaging system. Volume and planar imaging techniques utilizing saturation recovery, proton TI-weighted relaxation time pulse sequences produced images of the heart and great vessels with exquisite anatomic detail that showed excellent correlation with cadaver sections of the heart. The left ventricular myocardial segments also showed excellent correlation with cadaver sections of the heart. The left ventricular myocardial segments also showed excellent correlation with the thallium-201 cardiac single photon emission computed tomography images. Volume acquisition allowed postprocessing selection of tomographic sections in various orientations to optimize visualization of a particular structure of interest. The excellent spatial and contrast resolution afforded by MR volume imaging, which does not involve the use of ionizing radiation and iodinated contrast material, should assure it a significant role in the diagnostic assessment of the cardiovascular system

  6. Evolution of the GATE project: new results and developments

    Energy Technology Data Exchange (ETDEWEB)

    Santin, G. [ESA-ESTEC, Keplerlaan 1, 2200 AG Noordwijk (Netherlands); Staelens, S. [ELIS Department, Ghent University, B-9000 Ghent (Belgium); Taschereau, R. [CRUMP Institute for Molecular Imaging, University of California Los Angeles, 700 Westwood Plaza A438, Los Angeles, CA 90095-1770 (United States); Descourt, P. [U650 INSERM, LaTIM, Brest (France); Schmidtlein, C.R. [Memorial Sloan-Kettering Cancer Center, New York, New York, US (United States); Simon, L. [Department of Radiation Oncology, Institut Curie, Paris (France); Visvikis, D. [U650 INSERM, LaTIM, Brest (France); Jan, S. [Service Hospitalier Frederic Joliot (SHFJ), CEA-Orsay, Orsay (France); Buvat, I. [U678 INSERM, CHU Pitie-Salpetriere, Paris (France)

    2007-10-15

    We present the status of the Geant4 Application for Emission Tomography (GATE) project, a Monte Carlo simulator for Single Photon Emission Computed Tomography (SPECT) and Positron annihilation Emission Tomography (PET). Its main features are reminded, including modelling of time dependent phenomena and versatile, user-friendly scripting interface. The focus of this manuscript will be on new developments introduced in the past 4 years. New results have been achieved in the fields of validation on real medical and research PET and SPECT systems, voxel geometries, digitisation, distributed computing and dosimetry.

  7. Evolution of the GATE project: new results and developments

    International Nuclear Information System (INIS)

    Santin, G.; Staelens, S.; Taschereau, R.; Descourt, P.; Schmidtlein, C.R.; Simon, L.; Visvikis, D.; Jan, S.; Buvat, I.

    2007-01-01

    We present the status of the Geant4 Application for Emission Tomography (GATE) project, a Monte Carlo simulator for Single Photon Emission Computed Tomography (SPECT) and Positron annihilation Emission Tomography (PET). Its main features are reminded, including modelling of time dependent phenomena and versatile, user-friendly scripting interface. The focus of this manuscript will be on new developments introduced in the past 4 years. New results have been achieved in the fields of validation on real medical and research PET and SPECT systems, voxel geometries, digitisation, distributed computing and dosimetry

  8. Analysis of the cardiac motion in myocardial infarction by the ECG-synchronized CT

    International Nuclear Information System (INIS)

    Watanabe, Shigeru; Shimizu, Masahiko; Yoshida, Hideo; Morooka, Nobuhiro; Shukuya, Masaki

    1981-01-01

    The cardiac motion in patients with myocardial infarction was analyzed by the ECG-synchronized computed tomography (CT). For ECG synchronization, the ECG gating method and the data sorting method were used. By the ECG gating method, the gated cardiac images during 0.1 msec intervals at end-diastolic and the end-systolic phases were obtained. By the data sorting method, phasic CT images were reconstructed retrospectively by selecting appropriate data from a series of consecutive scans taken with simultaneous continuous ECG recordings. Six normal subjects and eight patients with myocardial infarction were studied by the ECG gating method, and 14 normal subjects and 25 patients with myocardial infarction were studied by the data sorting method. The end-diastolic and the end-systolic pictures at mid left ventricular level were superimposed and the cardiac borders were traced for the analysis (Fig. 4). Then the cardiac cross-sectional areas at each cardiac phase (40 msec) were calculated, and a cardiac area curve was obtained by plotting them consecutively. The cross-sectional images were divided into right anterior, right posterior, left anterior and left posterior segments. Cardiac area curves of the each segment were also obtained for further analysis. From these curves, the changing ratio of cardiac areas (maximum area - minimum area/maximum area) and the maximum area velocity in systole and diastole were calculated. On the images and the cardiac area curves in myocardial infarction patients, abnormal myocardial movements such as partial akinesis, hypokinesis or paradoxical movement were apparent asd the area of abnormal motions corresponded well with the location of infarction determined by ECG, RI scanning and angiography. A decrease of the changing ratio and the velocity in the infarction area were shown (Fig. 6, 7) and the functional disturbances were suggested during not only systole but diastole also. (author)

  9. Anti-addiction drug ibogaine inhibits voltage-gated ionic currents: A study to assess the drug's cardiac ion channel profile

    International Nuclear Information System (INIS)

    Koenig, Xaver; Kovar, Michael; Rubi, Lena; Mike, Agnes K.; Lukacs, Peter; Gawali, Vaibhavkumar S.; Todt, Hannes; Hilber, Karlheinz; Sandtner, Walter

    2013-01-01

    The plant alkaloid ibogaine has promising anti-addictive properties. Albeit not licenced as a therapeutic drug, and despite hints that ibogaine may perturb the heart rhythm, this alkaloid is used to treat drug addicts. We have recently reported that ibogaine inhibits human ERG (hERG) potassium channels at concentrations similar to the drugs affinity for several of its known brain targets. Thereby the drug may disturb the heart's electrophysiology. Here, to assess the drug's cardiac ion channel profile in more detail, we studied the effects of ibogaine and its congener 18-Methoxycoronaridine (18-MC) on various cardiac voltage-gated ion channels. We confirmed that heterologously expressed hERG currents are reduced by ibogaine in low micromolar concentrations. Moreover, at higher concentrations, the drug also reduced human Na v 1.5 sodium and Ca v 1.2 calcium currents. Ion currents were as well reduced by 18-MC, yet with diminished potency. Unexpectedly, although blocking hERG channels, ibogaine did not prolong the action potential (AP) in guinea pig cardiomyocytes at low micromolar concentrations. Higher concentrations (≥ 10 μM) even shortened the AP. These findings can be explained by the drug's calcium channel inhibition, which counteracts the AP-prolonging effect generated by hERG blockade. Implementation of ibogaine's inhibitory effects on human ion channels in a computer model of a ventricular cardiomyocyte, on the other hand, suggested that ibogaine does prolong the AP in the human heart. We conclude that therapeutic concentrations of ibogaine have the propensity to prolong the QT interval of the electrocardiogram in humans. In some cases this may lead to cardiac arrhythmias. - Highlights: • We study effects of anti-addiction drug ibogaine on ionic currents in cardiomyocytes. • We assess the cardiac ion channel profile of ibogaine. • Ibogaine inhibits hERG potassium, sodium and calcium channels. • Ibogaine’s effects on ion channels are a potential

  10. Cardiac retention of PET neuronal imaging agent LMI1195 in different species: Impact of norepinephrine uptake-1 and -2 transporters

    International Nuclear Information System (INIS)

    Yu, Ming; Bozek, Jody; Kagan, Mikhail; Guaraldi, Mary; Silva, Paula; Azure, Michael; Onthank, David; Robinson, Simon P.

    2013-01-01

    Introduction: Released sympathetic neurotransmitter norepinephrine (NE) in the heart is cleared by neuronal uptake-1 and extraneuronal uptake-2 transporters. Cardiac uptake-1 and -2 expression varies among species, but the uptake-1 is the primary transporter in humans. LMI1195 is an NE analog labeled with 18 F for PET evaluation of cardiac neuronal function. This study investigated the impact of cardiac neuronal uptake-1 associated with different species on LMI1195 heart uptake. Methods: Cardiac uptake-1 was blocked by desipramine, a selective uptake-1 inhibitor, and sympathetic neuronal denervation was induced by 6-hydroxydopamine, a neurotoxin, in rats, rabbits and nonhuman primates (NHP). Tissue biodistribution and cardiac imaging of LMI1195 and 123 I-metaiodobenzylguanidine (MIBG) were performed. Results: In rats, uptake-1 blockade did not alter LMI1195 heart uptake compared to the control at 60-min post injection [1.41 ± 0.07 vs. 1.47 ± 0.23 % injected dose per gram tissue (%ID/g)]. In contrast, LMI1195 heart uptake was reduced by 80% in uptake-1 blocked rabbits. In sympathetically denervated rats, LMI1195 heart uptake was similar to the control (2.18 ± 0.40 vs. 2.58 ± 0.76 %ID/g). However, the uptake decreased by 79% in denervated rabbits. Similar results were found in MIBG heart uptake in rats and rabbits with uptake-1 blockade. Consistently, LMI1195 cardiac imaging showed comparable myocardial activity in uptake-1 blocked or sympathetically denervated rats to the control, but marked activity reduction in uptake-1 blocked or denervated rabbits and NHPs. Conclusions: LMI1195 is retained in the heart of rabbits and NHPs primarily via the neuronal uptake-1 with high selectivity and can be used for evaluation of cardiac sympathetic denervation. Similar to the human, the neuronal uptake-1 is the dominant transporter for cardiac retention of NE analogs in rabbits and NHPs, but not in rats

  11. Cardiac magnetic resonance: is phonocardiogram gating reliable in velocity-encoded phase contrast imaging?

    International Nuclear Information System (INIS)

    Nassenstein, Kai; Schlosser, Thomas; Orzada, Stephan; Ladd, Mark E.; Maderwald, Stefan; Haering, Lars; Czylwik, Andreas; Jensen, Christoph; Bruder, Oliver

    2012-01-01

    To assess the diagnostic accuracy of phonocardiogram (PCG) gated velocity-encoded phase contrast magnetic resonance imaging (MRI). Flow quantification above the aortic valve was performed in 68 patients by acquiring a retrospectively PCG- and a retrospectively ECG-gated velocity-encoded GE-sequence at 1.5 T. Peak velocity (PV), average velocity (AV), forward volume (FV), reverse volume (RV), net forward volume (NFV), as well as the regurgitant fraction (RF) were assessed for both datasets, as well as for the PCG-gated datasets after compensation for the PCG trigger delay. PCG-gated image acquisition was feasible in 64 patients, ECG-gated in all patients. PCG-gated flow quantification overestimated PV (Δ 3.8 ± 14.1 cm/s; P = 0.037) and underestimated FV (Δ -4.9 ± 15.7 ml; P = 0.015) and NFV (Δ -4.5 ± 16.5 ml; P = 0.033) compared with ECG-gated imaging. After compensation for the PCG trigger delay, differences were only observed for PV (Δ 3.8 ± 14.1 cm/s; P = 0.037). Wide limits of agreement between PCG- and ECG-gated flow quantification were observed for all variables (PV: -23.9 to 31.4 cm/s; AV: -4.5 to 3.9 cm/s; FV: -35.6 to 25.9 ml; RV: -8.0 to 7.2 ml; NFV: -36.8 to 27.8 ml; RF: -10.4 to 10.2 %). The present study demonstrates that PCG gating in its current form is not reliable enough for flow quantification based on velocity-encoded phase contrast gradient echo (GE) sequences. (orig.)

  12. ECG gated magnetic resonance imaging in cardiovascular disease

    International Nuclear Information System (INIS)

    Park, Jae Hyung; Im, Chung Kie; Han, Man Chung; Kim, Chu Wan

    1985-01-01

    Using KAIS 0.15 Tesla resistive magnetic imaging system, ECG gated magnetic resonance (MR) image of various cardiovascular disease was obtained in 10 patients. The findings of MR image of the cardiovascular disease were analysed and the results were as follows: 1. In 6 cases of acquired and congenital cardiac diseases, there were 2 cases of myocardial infarction, 1 case of mitral stenosis and 3 cases of corrected transportation of great vessels. The others were 3 cases of aortic disease and 1 case of pericardial effusion with lymphoma. 2. Myocardial thinning and left ventricular aneurysm were detected in MR images of myocardial infarction. The left atrium was well delineated and enlarged in the case of mitral stenosis. And segmental analysis was possible in the cases of corrected transposition since all cardiac structures were well delineated anatomically. 3. In aortic diseases, the findings of MR image were enlarged lumen, compressed cardiac chambers in ascending aortic aneurysm, intimal flap, enhanced false lumen in dissecting aneurysm and irregular narrowing of aorta with arterial obstruction in Takayasu's arteritis. 4. Pericardial effusion revealed a conspicuous contrast with neighboring mediastinal fat and cardiac wall due to it low signal encircling cardiac wall. 5. ECG gated MR image is an accurate non-invasive imaging modality for the diagnosis of cardiovascular disease and better results of its clinical application are expected in the future with further development in the imaging system and more clinical experiences

  13. The continual innovation of commercial PET/CT solutions in nuclear cardiology: Siemens Healthineers.

    Science.gov (United States)

    Bendriem, Bernard; Reed, Jessie; McCullough, Kathryn; Khan, Mohammad Raza; Smith, Anne M; Thomas, Damita; Long, Misty

    2018-04-10

    Cardiac PET/CT is an evolving, non-invasive imaging modality that impacts patient management in many clinical scenarios. Beyond offering the capability to assess myocardial perfusion, inflammatory cardiac pathologies, and myocardial viability, cardiac PET/CT also allows for the non-invasive quantitative assessment of myocardial blood flow (MBF) and myocardial flow reserve (MFR). Recognizing the need for an enhanced comprehension of coronary physiology, Siemens Healthineers implemented a sophisticated solution for the calculation of MBF and MFR in 2009. As a result, each aspect of their innovative scanner and image-processing technology seamlessly integrates into an efficient, easy-to-use workflow for everyday clinical use that maximizes the number of patients who potentially benefit from this imaging modality.

  14. Evaluation of Paradoxical Septal Motion Following Cardiac Surgery with Gated Cardiac Blood Pool Scan

    International Nuclear Information System (INIS)

    Shin, Seong Hae; Chung, June Key; Lee, Myung Chul; Cho, Bo Youn; Koh, Chang Soon; Suh, Kyung Phil

    1985-01-01

    The development of paradoxical interventricular septal motion is a common consequence of cardiopulmonary bypass operation. The reason for this postoperative abnormal septal motion is not clear. 41 patients were studied preoperatively and postoperatively with radionuclide blood pool scan to evaluate the frequency of development of paradoxical septal motion with right ventricular volume overload before surgery and the frequency of development of paradoxical septal motion after cardiac surgery with cardiopulmonary bypass, and to evaluate the change of EF related to the development of paradoxical septal motion after cardiac surgery. The results were as follows; 1) 7 of 41 patients with right ventricular volume overload (that is 17%) showed paradoxical septal motion before surgery. But 13 of 34 patients (that is 42%) had paradoxical septal motion after cardiac surgery with cardiopulmonary bypass. So open heart surgery with cardiopulmonary bypass related the development of paradoxical septal motion after surgery. 2) EF significantly decreased in patients who developed paradoxical septal motion after surgery, whereas the EF did not change in the patients who retained normal interventricular septal motion after surgery. So paradoxical septal motion usually reflected some diminution of left ventricular function, immediately after cardiac surgery.

  15. Evaluation of Paradoxical Septal Motion Following Cardiac Surgery with Gated Cardiac Blood Pool Scan

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Seong Hae; Chung, June Key; Lee, Myung Chul; Cho, Bo Youn; Koh, Chang Soon; Suh, Kyung Phil [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1985-03-15

    The development of paradoxical interventricular septal motion is a common consequence of cardiopulmonary bypass operation. The reason for this postoperative abnormal septal motion is not clear. 41 patients were studied preoperatively and postoperatively with radionuclide blood pool scan to evaluate the frequency of development of paradoxical septal motion with right ventricular volume overload before surgery and the frequency of development of paradoxical septal motion after cardiac surgery with cardiopulmonary bypass, and to evaluate the change of EF related to the development of paradoxical septal motion after cardiac surgery. The results were as follows; 1) 7 of 41 patients with right ventricular volume overload (that is 17%) showed paradoxical septal motion before surgery. But 13 of 34 patients (that is 42%) had paradoxical septal motion after cardiac surgery with cardiopulmonary bypass. So open heart surgery with cardiopulmonary bypass related the development of paradoxical septal motion after surgery. 2) EF significantly decreased in patients who developed paradoxical septal motion after surgery, whereas the EF did not change in the patients who retained normal interventricular septal motion after surgery. So paradoxical septal motion usually reflected some diminution of left ventricular function, immediately after cardiac surgery.

  16. Dynamic low dose I-123-iodophenylpentadecanoic acid metabolic cardiac imaging

    International Nuclear Information System (INIS)

    Murray, G.L.; Magill, H.L.; Schad, N.C.

    1993-01-01

    Recognition of stunned and hibernating myocardium is essential in this era of cardiac revascularization. Positron emission tomography (PET) accurately identifies viability but is costly and unavailable to most patients. Dynamic low dose I-123-iodophenylpentadecanoic acid (IPPA) metabolic cardiac imaging is a potentially cost-effective alternative to PET. Using transmural myocardial biopsies obtained during coronary bypass surgery as the viability gold standard, resting IPPA imaging agreed with 39/43 (91%) biopsies, with a sensitivity for viability of 33/36(92%) and a specificity of 6/7 (86%) in patients with severe ischemic cardiomyopathy. Eighty percent of IPPA viable, infarcted segments improved wall motion postoperatively. Furthermore, when compared to reinjection thallium (SPECT-Tl) scans after myocardial infarction, there was IPPA-Tl concordance in 27/35 (77%)(Kappa=0.536, p=0.0003). Similar to PET, IPPA demonstrated more viability than SPECT-Tl, 26/35 (74%) vs. 18/35 (51%)(p=0.047). Finally, when compared to transvenous endomyocardial biopsy for detecting rejection following cardiac transplantation, IPPA sensitivity for ≥Grade II rejection was 100%, and IPPA screening assessment for the necessity of biopsy could result in a 31% cost-savings. Therefore, IPPA metabolic cardiac imaging is a safe, inexpensive technique with a promising future. (author)

  17. Preliminary results of a prototype C-shaped PET designed for an in-beam PET system

    International Nuclear Information System (INIS)

    Kim, Hyun-Il; Chung, Yong Hyun; Lee, Kisung; Kim, Kyeong Min; Kim, Yongkwon; Joung, Jinhun

    2016-01-01

    Positron emission tomography (PET) can be utilized in particle beam therapy to verify the dose distribution of the target volume as well as the accuracy of the treatment. We present an in-beam PET scanner that can be integrated into a particle beam therapy system. The proposed PET scanner consisted of 14 detector modules arranged in a C-shape to avoid blockage of the particle beam line by the detector modules. Each detector module was composed of a 9×9 array of 4.0 mm×4.0 mm×20.0 mm LYSO crystals optically coupled to four 29-mm-diameter PMTs using the photomultiplier-quadrant-sharing (PQS) technique. In this study, a Geant4 Application for Tomographic Emission (GATE) simulation study was conducted to design a C-shaped PET scanner and then experimental evaluation of the proposed design was performed. The spatial resolution and sensitivity were measured according to NEMA NU2-2007 standards and were 6.1 mm and 5.61 cps/kBq, respectively, which is in good agreement with our simulation, with an error rate of 12.0%. Taken together, our results demonstrate the feasibility of the proposed C-shaped in-beam PET system, which we expect will be useful for measuring dose distribution in particle therapy.

  18. Influence of PET/CT-introduction on PET scanning frequency and indications. Results of a multicenter study

    International Nuclear Information System (INIS)

    Stergar, H.; Bockisch, A.; Eschmann, S.M.; Krause, B.J.; Roedel, R.; Tiling, R.; Weckesser, M.

    2007-01-01

    Aim: to evaluate the influence of the introduction of combined PET/CT scanners into clinical routine. This investigation addresses the quantitative changes between PET/CT and stand alone PET. Methods: the study included all examinations performed on stand alone PET- or PET/CT-scanners within 12 month prior to and after implementation of PET/CT. The final data analysis included five university hospitals and a total number of 15 497 exams. We distinguished exams on stand alone tomographs prior to and after installation of the combined device as well as PET/CT scans particularly with regard to disease entities. Various further parameters were investigated. Results: the overall number of PET scans (PET and PET/CT) rose by 146% while the number of scans performed on stand alone scanners declined by 22%. Only one site registered an increase in stand alone PET. The number of exams for staging in oncology increased by 196% while that of cardiac scans decreased by 35% and the number of scans in neurology rose by 47%. The use of scans for radiotherapy planning increased to 7% of all PET/CT studies. The increase of procedures for so-called classic PET oncology indications was moderate compared to the more common tumors. An even greater increase was observed in some rare entities. Conclusions: the introduction of PET/CT led to more than a doubling of overall PET procedures with a main focus on oncology. Some of the observed changes in scanning frequency may be caused by a rising availability of new radiotracers and advancements of competing imaging methods. Nevertheless the evident increase in the use of PET/CT for the most common tumour types demonstrates its expanding role in cancer staging. The combination of molecular and morphologic imaging has not only found its place but is still gaining greater importance with new developments in technology and radiochemistry. (orig.)

  19. MO-FG-BRA-05: Dosimetric and Radiobiological Validation of Respiratory Gating in Conventional and Hypofractionated Radiotherapy of the Lung: Effect of Dose, Dose Rate, Gating Window and Breathing Pattern

    Energy Technology Data Exchange (ETDEWEB)

    Cervino, L; Soultan, D; Pettersson, N; Yock, A; Cornell, M; Aguilera, J; Murphy, J; Advani, S; Moiseenko, V [University of California, San Diego, La Jolla, CA (United States); Gill, B [British Columbia Cancer Agency, Vancouver, BC (Canada)

    2016-06-15

    Purpose: to evaluate the dosimetric and radiobiological consequences from having different gating windows, dose rates, and breathing patterns in gated VMAT lung radiotherapy. Methods: A novel 3D-printed moving phantom with central high and peripheral low tracer uptake regions was 4D FDG-PET/CT-scanned using ideal, patient-specific regular, and irregular breathing patterns. A scan of the stationary phantom was obtained as a reference. Target volumes corresponding to different uptake regions were delineated. Simultaneous integrated boost (SIB) 6 MV VMAT plans were produced for conventional and hypofractionated radiotherapy, using 30–70 and 100% cycle gating scenarios. Prescribed doses were 200 cGy with SIB to 240 cGy to high uptake volume for conventional, and 800 with SIB to 900 cGy for hypofractionated plans. Dose rates of 600 MU/min (conventional and hypofractionated) and flattening filter free 1400 MU/min (hypofractionated) were used. Ion chamber measurements were performed to verify delivered doses. Vials with A549 cells placed in locations matching ion chamber measurements were irradiated using the same plans to measure clonogenic survival. Differences in survival for the different doses, dose rates, gating windows, and breathing patterns were analyzed. Results: Ion chamber measurements agreed within 3% of the planned dose, for all locations, breathing patterns and gating windows. Cell survival depended on dose alone, and not on gating window, breathing pattern, MU rate, or delivery time. The surviving fraction varied from approximately 40% at 2Gy to 1% for 9 Gy and was within statistical uncertainty relative to that observed for the stationary phantom. Conclusions: Use of gated VMAT in PET-driven SIB radiotherapy was validated using ion chamber measurements and cell survival assays for conventional and hypofractionated radiotherapy.

  20. Rapid detection of cardiac troponin I using antibody-immobilized gate-pulsed AlGaN/GaN high electron mobility transistor structures

    Science.gov (United States)

    Yang, Jiancheng; Carey, Patrick; Ren, Fan; Wang, Yu-Lin; Good, Michael L.; Jang, Soohwan; Mastro, Michael A.; Pearton, S. J.

    2017-11-01

    We report a comparison of two different approaches to detecting cardiac troponin I (cTnI) using antibody-functionalized AlGaN/GaN High Electron Mobility Transistors (HEMTs). If the solution containing the biomarker has high ionic strength, there can be difficulty in detection due to charge-screening effects. To overcome this, in the first approach, we used a recently developed method involving pulsed biases applied between a separate functionalized electrode and the gate of the HEMT. The resulting electrical double layer produces charge changes which are correlated with the concentration of the cTnI biomarker. The second approach fabricates the sensing area on a glass slide, and the pulsed gate signal is externally connected to the nitride HEMT. This produces a larger integrated change in charge and can be used over a broader range of concentrations without suffering from charge-screening effects. Both approaches can detect cTnI at levels down to 0.01 ng/ml. The glass slide approach is attractive for inexpensive cartridge-type sensors.

  1. Processing optimization with parallel computing for the J-PET scanner

    Directory of Open Access Journals (Sweden)

    Krzemień Wojciech

    2015-12-01

    Full Text Available The Jagiellonian Positron Emission Tomograph (J-PET collaboration is developing a prototype time of flight (TOF-positron emission tomograph (PET detector based on long polymer scintillators. This novel approach exploits the excellent time properties of the plastic scintillators, which permit very precise time measurements. The very fast field programmable gate array (FPGA-based front-end electronics and the data acquisition system, as well as low- and high-level reconstruction algorithms were specially developed to be used with the J-PET scanner. The TOF-PET data processing and reconstruction are time and resource demanding operations, especially in the case of a large acceptance detector that works in triggerless data acquisition mode. In this article, we discuss the parallel computing methods applied to optimize the data processing for the J-PET detector. We begin with general concepts of parallel computing and then we discuss several applications of those techniques in the J-PET data processing.

  2. Age- and gender-specific differences in left ventricular cardiac function and volumes determined by gated SPET

    International Nuclear Information System (INIS)

    Bondt, P. de; Wiele, C. van de; Winter, F. de; Dierckx, R.A.; Sutter, J. de; Backer, G. de

    2001-01-01

    The aim of this study was to determine normative volumetric data and ejection fraction values derived from gated myocardial single-photon emission tomography (SPET) using the commercially available software algorithm QGS (quantitative gated SPET). From a prospective database of 876 consecutive patients who were referred for a 2-day stress-rest technetium-99m tetrofosmin (925 MBq) gated SPET study, 102 patients (43 men, 59 women) with a low (<10%) pre-test likelihood of coronary disease were included (mean age 57.6 years). For stress imaging, a bicycle protocol was used in 79 of the patients and a dipyridamole protocol in 23. Left ventricular ejection fraction (LVEF) and end-diastolic and -systolic volumes (EDV and ESV) were calculated by QGS. EDV and ESV were corrected for body surface area, indicated by EDVi and ESVi. To allow comparison with previous reports using other imaging modalities, men and women were divided into three age groups (<45 years, ≥45 years but <65 years and ≥65 years). Men showed significantly higher EDVi and ESVi values throughout and lower LVEF values when compared with women in the subgroup ≥65 years (P<0.05, ANOVA). Significant negative and positive correlations were found between age and EDVi and ESVi values for both women and men and between LVEF and age in women (Pearson P≤0.01). LVEF values at bicycle stress were significantly higher than at rest (P=0.000, paired t test), which was the result of a significant decrease in ESV (P=0.003), a phenomenon which did not occur following dipyridamole stress (P=0.409). The data presented suggest that LVEF and EDVi and ESVi as assessed by QGS are strongly gender-specific. Although the physiological significance of these results is uncertain and needs further study, these findings demonstrate that the evaluation of cardiac function and volumes of patients by means of QGS should consider age- and gender-matched normative values. (orig.)

  3. Automatic extraction of forward stroke volume using dynamic PET/CT

    DEFF Research Database (Denmark)

    Harms, Hans; Tolbod, Lars Poulsen; Hansson, Nils Henrik

    Background: Dynamic PET can be used to extract forward stroke volume (FSV) by the indicator dilution principle. The technique employed can be automated and is in theory independent on the tracer used and may therefore be added to any dynamic cardiac PET protocol. The aim of this study...... was to validate automated methods for extracting FSV directly from dynamic PET studies for two different tracers and to examine potential scanner hardware bias. Methods: 21 subjects underwent a dynamic 27 min 11C-acetate PET scan on a Siemens Biograph TruePoint 64 PET/CT scanner (scanner I). In addition, 8...... subjects underwent a dynamic 6 min 15O-water PET scan followed by a 27 min 11C-acetate PET scan on a GE Discovery ST PET/CT scanner (scanner II). The LV-aortic time-activity curve (TAC) was extracted automatically from dynamic PET data using cluster analysis. The first-pass peak was isolated by automatic...

  4. Quantitative myocardial blood flow with Rubidium-82 PET

    DEFF Research Database (Denmark)

    Hagemann, Christoffer E; Ghotbi, Adam A; Kjær, Andreas

    2015-01-01

    Positron emission tomography (PET) allows assessment of myocardial blood flow in absolute terms (ml/min/g). Quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR) extend the scope of conventional semi-quantitative myocardial perfusion imaging (MPI): e.g. in 1) identificat......Positron emission tomography (PET) allows assessment of myocardial blood flow in absolute terms (ml/min/g). Quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR) extend the scope of conventional semi-quantitative myocardial perfusion imaging (MPI): e.g. in 1...... global MFR and major adverse cardiovascular events (MACE), and together with new diagnostic possibilities from measuring the longitudinal myocardial perfusion gradient, cardiac (82)Rb PET faces a promising clinical future. This article reviews current evidence on quantitative (82)Rb PET's ability...

  5. Prognostic study of risk stratification among Japanese patients with ischemic heart disease using gated myocardial perfusion SPECT: J-ACCESS study

    International Nuclear Information System (INIS)

    Nishimura, Tsunehiko; Nakajima, Kenichi; Kusuoka, Hideo; Yamashina, Akira; Nishimura, Shigeyuki

    2008-01-01

    Although the prognostic value of myocardial perfusion imaging using gated single photon emission computed tomography (SPECT) for predicting major cardiac events has been evaluated, little is known about the relevance of this procedure to the Japanese population. A total of 4,031 consecutive Japanese patients with suspected or confirmed ischemic heart diseases were registered at 117 hospitals in the Japanese Assessment of Cardiac Events and Survival Study by Quantitative Gated SPECT investigation. Gated stress/rest myocardial perfusion SPECT was performed and the patients were followed up for 3 years. Segmental perfusion scores and quantitative gated SPECT results were calculated. Major cardiac events were defined as cardiac death, nonfatal myocardial infarction, and severe heart failure. During the 3-year follow-up, cardiac death (n = 57) and nonfatal myocardial infarction (n = 39) occurred in 96 patients (2.4%/3 years) when hard events were the endpoints. When severe heart failure was included as an endpoint, major cardiac events that developed in 175 patients (4.3%/3 years) comprised cardiac death (n = 45), nonfatal myocardial infarction (n = 37), and severe heart failure (n = 93). Normal and severely abnormal summed stress score values were associated with low (2.31%/3 years) and high (9.21%/3 years) rates of major cardiac events, respectively. Rates of major cardiac events were significantly higher in patients with ejection fraction (EF) <45% than in those with EF 45% or higher (16.55 vs 2.94%/3 years; P < 0.001). The incidence of major cardiac events within 3 years was also significantly higher among patients with high end-systolic volumes. The major event rates were similar among nondiabetic patients with and diabetic patients without prior myocardial infarction at 5.06% and 5.73%/3 years, respectively. Cardiac event rates were significantly lower in the Japanese than in the USA and European populations. However, large myocardial perfusion defects and

  6. Targeting sodium channels in cardiac arrhythmia

    NARCIS (Netherlands)

    Remme, Carol Ann; Wilde, Arthur A. M.

    2014-01-01

    Cardiac voltage-gated sodium channels are responsible for proper electrical conduction in the heart. During acquired pathological conditions and inherited sodium channelopathies, altered sodium channel function causes conduction disturbances and ventricular arrhythmias. Although the clinical,

  7. Assessment of the diagnostic accuracy of {sup 18}F-FDG PET/CT in prosthetic infective endocarditis and cardiac implantable electronic device infection: comparison of different interpretation criteria

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez-Ballve, Ana; Jesus Perez-Castejon, Maria; Carreras-Delgado, Jose L. [Clinico San Carlos University Hospital, San Carlos Health Research Institute (IdISSC), Complutense University of Madrid, Department of Nuclear Medicine, Madrid (Spain); Delgado-Bolton, Roberto C. [Clinico San Carlos University Hospital, San Carlos Health Research Institute (IdISSC), Complutense University of Madrid, Department of Nuclear Medicine, Madrid (Spain); San Pedro Hospital and Centre for Biomedical Research of La Rioja (CIBIR), University of La Rioja, Department of Diagnostic Imaging (Radiology) and Nuclear Medicine, La Rioja (Spain); Sanchez-Enrique, Cristina; Vilacosta, Isidre; Vivas, David; Olmos, Carmen [Clinico San Carlos University Hospital, Department of Cardiology, Madrid (Spain); Ferrer, Manuel E.F. [Clinico San Carlos University Hospital, Research Unit, Madrid (Spain)

    2016-12-15

    The diagnosis of prosthetic valve (PV) infective endocarditis (IE) and infection of cardiac implantable electronic devices (CIEDs) remains challenging. The aim of this study was to assess the usefulness of {sup 18}F-FDG PET/CT in these patients and analyse the interpretation criteria. We included 41 patients suspected of having IE by the Duke criteria who underwent {sup 18}F-FDG PET/CT. The criteria applied for classifying the findings as positive/negative for IE were: (a) visual analysis of only PET images with attenuation-correction (AC PET images); (b) visual analysis of both AC PET images and PET images without AC (NAC PET images); (c) qualitative analysis of NAC PET images; and (d) semiquantitative analysis of AC PET images. {sup 18}F-FDG PET/CT was considered positive for IE independently of the intensity and distribution of FDG uptake. The gold standard was the Duke pathological criteria (if tissue was available) or the decision of an endocarditis expert team after a minimum 4 months follow-up. We studied 62 areas with suspicion of IE, 28 areas (45 %) showing definite IE and 34 (55 %) showing possible IE. Visual analysis of only AC PET images showed poor diagnostic accuracy (sensitivity 20 %, specificity 57 %). Visual analysis of both AC PET and NAC PET images showed excellent sensitivity (100 %) and intermediate specificity (73 %), focal uptake being more frequently associated with IE. The accuracy of qualitative analysis of NAC PET images depended on the threshold: the maximum sensitivity, specificity and accuracy achieved were 88 %, 80 %, 84 %, respectively. In the semiquantitative analysis of AC PET images, SUVmax was higher in areas of confirmed IE than in those without IE (∇SUVmax 2.2, p < 0.001). When FDG uptake was twice that in the liver, IE was always confirmed, and SUVmax 5.5 was the optimal threshold for IE diagnosis using ROC curve analysis (area under the curve 0.71). The value of {sup 18}F-FDG PET/CT in the diagnosis of suspected IE of PVs

  8. Assessment of the diagnostic accuracy of "1"8F-FDG PET/CT in prosthetic infective endocarditis and cardiac implantable electronic device infection: comparison of different interpretation criteria

    International Nuclear Information System (INIS)

    Jimenez-Ballve, Ana; Jesus Perez-Castejon, Maria; Carreras-Delgado, Jose L.; Delgado-Bolton, Roberto C.; Sanchez-Enrique, Cristina; Vilacosta, Isidre; Vivas, David; Olmos, Carmen; Ferrer, Manuel E.F.

    2016-01-01

    The diagnosis of prosthetic valve (PV) infective endocarditis (IE) and infection of cardiac implantable electronic devices (CIEDs) remains challenging. The aim of this study was to assess the usefulness of "1"8F-FDG PET/CT in these patients and analyse the interpretation criteria. We included 41 patients suspected of having IE by the Duke criteria who underwent "1"8F-FDG PET/CT. The criteria applied for classifying the findings as positive/negative for IE were: (a) visual analysis of only PET images with attenuation-correction (AC PET images); (b) visual analysis of both AC PET images and PET images without AC (NAC PET images); (c) qualitative analysis of NAC PET images; and (d) semiquantitative analysis of AC PET images. "1"8F-FDG PET/CT was considered positive for IE independently of the intensity and distribution of FDG uptake. The gold standard was the Duke pathological criteria (if tissue was available) or the decision of an endocarditis expert team after a minimum 4 months follow-up. We studied 62 areas with suspicion of IE, 28 areas (45 %) showing definite IE and 34 (55 %) showing possible IE. Visual analysis of only AC PET images showed poor diagnostic accuracy (sensitivity 20 %, specificity 57 %). Visual analysis of both AC PET and NAC PET images showed excellent sensitivity (100 %) and intermediate specificity (73 %), focal uptake being more frequently associated with IE. The accuracy of qualitative analysis of NAC PET images depended on the threshold: the maximum sensitivity, specificity and accuracy achieved were 88 %, 80 %, 84 %, respectively. In the semiquantitative analysis of AC PET images, SUVmax was higher in areas of confirmed IE than in those without IE (∇SUVmax 2.2, p < 0.001). When FDG uptake was twice that in the liver, IE was always confirmed, and SUVmax 5.5 was the optimal threshold for IE diagnosis using ROC curve analysis (area under the curve 0.71). The value of "1"8F-FDG PET/CT in the diagnosis of suspected IE of PVs and CIEDs is

  9. Evaluation by means of ECG-gated cardiac blood pool scintigraphy of global and regional left ventricular function at rest and during exercise in patients with coronary artery disease

    International Nuclear Information System (INIS)

    Sauer, E.; Sebening, H.; Lutilsky, L.; Dressler, H.; Hoer, G.; Pabst, H.W.; Bloemer, H.; Technische Univ. Muenchen

    1978-01-01

    ECG-gated cardiac blood pool scintigraphy permits a non-invasive determination of the end-diastolic and end-systolic ventricular volumens and of the ejection fraction as well as a qualitative description of regional ventricular wall motion at rest and during exercise. In 6 healthy persons a significant increase of the ejection fraction from 66 +- 7% at rest to 78 +- 3% during exercise (p [de

  10. ECG-gated multislice spiral CT for diagnosis of acute pulmonary embolism

    International Nuclear Information System (INIS)

    Marten, K.; Engelke, C.; Funke, M.; Obenauer, S.; Baum, F.; Grabbe, E.

    2003-01-01

    AIM: The purpose of this study was to determine the feasibility of echocardiogram (ECG)-gated multi-slice CT angiography (MCTA) in patients with clinical suspicion of acute venous thromboembolism (VTE), to investigate the effect of ECG-gating on cardiac motion artefacts, and to determine the diagnostic reader agreement of ECG-gated MCTA in comparison with conventional MCTA. MATERIALS AND METHODS: Forty-eight consecutive patients were prospectively enrolled and randomly underwent ECG-gated (n=25, group 1) or non-ECG-gated (n=23, group 2) eight-slice pulmonary MCTA. Image data were evaluated by three independent chest radiologists with respect to the presence or absence of emboli at different arterial levels (main, lobar, segmental, and subsegmental arteries), and with regard to cardiac motion artefacts. Statistical tests used to calculate inter-observer agreement were weighted κ statistics, extended κ statistics and confidence indices indicating three-reader agreement accuracy. RESULTS: Twenty-seven patients (56.3%) were diagnosed to have pulmonary embolism (13 from group 1, 14 from group 2). Cardiac motion artefacts were significantly more frequent in group 2 (70% in group 2 versus 13% in group 1, p=0.0001). The overall diagnostic agreement was excellent with both MCTA techniques (three-reader confidence index for all vascular territories: 0.76 and 0.84 for groups 1 and 2, respectively (extended κ=0.69 and 0.78, respectively); three-reader confidence index for diagnosis of VTE: 0.94 and 0.85 for groups 1 and 2, respectively (extended κ=0.91 and 0.73, respectively), weighted κ=0.81-0.83 and 0.92-0.95 for groups 1 and 2, respectively, and did not differ significantly between the two groups. In addition there was no significant difference of inter-observer agreement in either group at any assessed pulmonary arterial level. CONCLUSION: ECG-gated pulmonary MCTA is feasible in patients with clinical suspicion of VTE. However, ECG-gated image acquisition did not

  11. Evaluation of a New Motion-correction Algorithm Using On-rigid Registration in Respiratory-gated PET/CT Images of Liver Tumors.

    Science.gov (United States)

    Wagatsuma, Kei; Osawa, Tatsufumi; Yokokawa, Naoki; Miwa, Kenta; Oda, Keiichi; Kudo, Yoshiro; Unno, Yasushi; Ito, Kimiteru; Ishii, Kenji

    2016-01-01

    The present study aimed to determine the qualitative and quantitative accuracy of the Q.Freeze algorithm in PET/CT images of liver tumors. A body phantom and hot spheres representing liver tumors contained 5.3 and 21.2 kBq/mL of a solution containing 18 F radioactivity, respectively. The phantoms were moved in the superior-inferior direction at a motion displacement of 20 mm. Conventional respiratory-gated (RG) and Q.Freeze images were sorted into 6, 10, and 13 phase-groups. The SUV ave was calculated from the background of the body phantom, and the SUV max was determined from the hot spheres of the liver tumors. Three patients with four liver tumors were also clinically assessed by whole-body and RG PET. The RG and Q.Freeze images derived from the clinical study were also sorted into 6, 10 and 13 phase-groups. Liver signal-to-noise ratio (SNR) and SUV max were determined from the RG and Q.Freeze clinical images. The SUV ave of Q.Freeze images was the same as those derived from the body phantom using RG. The liver SNR improved with Q.Freeze, and the SUVs max was not overestimated when Q.Freeze was applied in both the phantom and clinical studies. Q.Freeze did not degrade the liver SNR and SUV max even though the phase number was larger. Q.Freeze delivered qualitative and quantitative motion correction than conventional RG imaging even in 10-phase groups.

  12. Anti-addiction drug ibogaine inhibits voltage-gated ionic currents: A study to assess the drug's cardiac ion channel profile

    Energy Technology Data Exchange (ETDEWEB)

    Koenig, Xaver; Kovar, Michael; Rubi, Lena; Mike, Agnes K.; Lukacs, Peter; Gawali, Vaibhavkumar S.; Todt, Hannes [Center for Physiology and Pharmacology, Department of Neurophysiology and -pharmacology, Medical University of Vienna, 1090 Vienna (Austria); Hilber, Karlheinz, E-mail: karlheinz.hilber@meduniwien.ac.at [Center for Physiology and Pharmacology, Department of Neurophysiology and -pharmacology, Medical University of Vienna, 1090 Vienna (Austria); Sandtner, Walter [Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, 1090 Vienna (Austria)

    2013-12-01

    The plant alkaloid ibogaine has promising anti-addictive properties. Albeit not licenced as a therapeutic drug, and despite hints that ibogaine may perturb the heart rhythm, this alkaloid is used to treat drug addicts. We have recently reported that ibogaine inhibits human ERG (hERG) potassium channels at concentrations similar to the drugs affinity for several of its known brain targets. Thereby the drug may disturb the heart's electrophysiology. Here, to assess the drug's cardiac ion channel profile in more detail, we studied the effects of ibogaine and its congener 18-Methoxycoronaridine (18-MC) on various cardiac voltage-gated ion channels. We confirmed that heterologously expressed hERG currents are reduced by ibogaine in low micromolar concentrations. Moreover, at higher concentrations, the drug also reduced human Na{sub v}1.5 sodium and Ca{sub v}1.2 calcium currents. Ion currents were as well reduced by 18-MC, yet with diminished potency. Unexpectedly, although blocking hERG channels, ibogaine did not prolong the action potential (AP) in guinea pig cardiomyocytes at low micromolar concentrations. Higher concentrations (≥ 10 μM) even shortened the AP. These findings can be explained by the drug's calcium channel inhibition, which counteracts the AP-prolonging effect generated by hERG blockade. Implementation of ibogaine's inhibitory effects on human ion channels in a computer model of a ventricular cardiomyocyte, on the other hand, suggested that ibogaine does prolong the AP in the human heart. We conclude that therapeutic concentrations of ibogaine have the propensity to prolong the QT interval of the electrocardiogram in humans. In some cases this may lead to cardiac arrhythmias. - Highlights: • We study effects of anti-addiction drug ibogaine on ionic currents in cardiomyocytes. • We assess the cardiac ion channel profile of ibogaine. • Ibogaine inhibits hERG potassium, sodium and calcium channels. • Ibogaine’s effects on

  13. Photocontrol of Voltage-Gated Ion Channel Activity by Azobenzene Trimethylammonium Bromide in Neonatal Rat Cardiomyocytes.

    Directory of Open Access Journals (Sweden)

    Sheyda R Frolova

    Full Text Available The ability of azobenzene trimethylammonium bromide (azoTAB to sensitize cardiac tissue excitability to light was recently reported. The dark, thermally relaxed trans- isomer of azoTAB suppressed spontaneous activity and excitation propagation speed, whereas the cis- isomer had no detectable effect on the electrical properties of cardiomyocyte monolayers. As the membrane potential of cardiac cells is mainly controlled by activity of voltage-gated ion channels, this study examined whether the sensitization effect of azoTAB was exerted primarily via the modulation of voltage-gated ion channel activity. The effects of trans- and cis- isomers of azoTAB on voltage-dependent sodium (INav, calcium (ICav, and potassium (IKv currents in isolated neonatal rat cardiomyocytes were investigated using the whole-cell patch-clamp technique. The experiments showed that azoTAB modulated ion currents, causing suppression of sodium (Na+ and calcium (Ca2+ currents and potentiation of net potassium (K+ currents. This finding confirms that azoTAB-effect on cardiac tissue excitability do indeed result from modulation of voltage-gated ion channels responsible for action potential.

  14. Extraction of left ventricular myocardial mass from dynamic 11C-acetate PET

    DEFF Research Database (Denmark)

    Harms, Hans; Tolbod, Lars Poulsen; Hansson, Nils Henrik

    Background: Dynamic 11C-acetate PET is used to quantify oxygen metabolism, which is used to calculate left ventricular (LV) myocardial efficiency, an early marker of heart failure. This requires estimation of LV myocardial mass and is typically derived from a separate cardiovascular magnetic...... resonance (CMR) scan. The aim of this study was to explore the feasibility of estimating myocardial mass directly from a dynamic 11C-acetate PET scan. Methods: 21 subjects underwent a 27-min 11C-acetate PET scan on a Siemens Biograph TruePoint 64 PET/CT scanner. In addition, 10 subjects underwent a dynamic...... 11C-acetate 27-min PET scan on a GE Discovery ST PET/CT scanner. Parametric images of uptake rate K1 and both arterial (VA) and venous (VV) spillover fractions were generated using a basis function implementation of the standard single tissue compartment model using non-gated dynamic data. The LV...

  15. Estimating accidental coincidences for pixelated PET detectors and singles list-mode acquisition

    International Nuclear Information System (INIS)

    Rafecas, M.; Torres, I.; Spanoudaki, V.; McElroy, D.P.; Ziegler, S.I.

    2007-01-01

    We have studied the validity of random estimation techniques for various low energy thresholds (LETs) and single list-mode data sets in small animal PET. While a LET below 255 keV helps to increase the sensitivity, it also results in an increase of random coincidences and inter-crystal scatter (ICS). The study is carried out for MADPET-II, a dual-layer positron emission tomography (PET) scanner prototype consisting of LSO crystals read out individually by APDs. The data are acquired in singles list-mode format, and coincidences are computed post-acquisition. To estimate randoms, we have used the delayed coincidence window method (DW), and the singles rate model (SR). Various phantoms were simulated using GATE. For LETs under 255 keV, the number of random events R, estimated using the SR and the DW methods, is larger than the number of randoms which was directly computed from GATE simulations, and R(SR)>R(DW)>R(GATE). The higher the LET, the smaller the overestimation. For LETs >255 keV, R(DW)/R(GATE) ∼1. If scattered singles were excluded from the file, this discrepancy between R(DW or SR) and R(GATE) significantly diminished. This fact points out to ICS as the effect responsible for the mismatch, since for LETs lower than 255 keV, all singles related to an ICS event can be detected independently, thus altering the singles rate. Therefore, if low LETs are used, random estimation techniques should account for ICS

  16. Cardiac function in acute hypothyroidism

    International Nuclear Information System (INIS)

    Donaghue, K.; Hales, I.; Allwright, S.; Cooper, R.; Edwards, A.; Grant, S.; Morrow, A.; Wilmshurst, E.; Royal North Shore Hospital, Sydney

    1985-01-01

    It has been established that chronic hypothyroidism may affect cardiac function by several mechanisms. It is not known how long the patient has to be hypothyroid for cardiac involvement to develop. This study was undertaken to assess the effect of a short period of hypothyroidism (10 days) on cardiac function. Nine patients who had had total tyroidectomy, had received ablative radioiodine for thyroid cancer and were euthyroid on replacement therapy were studied while both euthyroid and hypothyroid. Cardiac assessment was performed by X-ray, ECG, echocardiography and gated blood-pool scans. After 10 days of hypothyroidisms, the left-ventricular ejection fraction failed to rise after exercise in 4 of the 9 patients studied, which was significant (P<0.002). No significant changes in cardiac size or function at rest were detected. This functional abnormality in the absence of any demonstrable change in cardiac size and the absence of pericardial effussion with normal basal function suggest that short periods of hypothyroidism may reduce cardiac reserve, mostly because of alterations in metabolic function. (orig.)

  17. Myocardial perfusion of infarcted and normal myocardium in propofol-anesthetized minipigs using 82Rubidium PET

    DEFF Research Database (Denmark)

    Rasmussen, Thomas; Larsen, Bjarke Follin; Kastrup, Jens

    2016-01-01

    Cardiac Rubidium-82 (82Rb) positron-emission-tomography (PET) is a good method for quantification of myocardial blood flow in man. Quantification of myocardial blood flow in animals to evaluate new treatment strategies or to understand underlying disease is also of great interest but raises some...... challenges. Animals, which have been anesthetized during PET acquisition, might react differently to used stress medications, and therefore difficulties might exist while evaluating the resulting PET images using standard software packages from commercial vendors optimized for human hearts. Furthermore...... propofol, used for anesthesia, can influence myocardial perfusion and coronary flow reserve due to its vasorelaxant effect, and interactions might exist between propofol and used stress agents, potentially affecting the result of the examination. We present cardiac 82Rb-PET studies performed in propofol...

  18. [Non-invasive evaluation of the cardiac autonomic nervous system by PET

    International Nuclear Information System (INIS)

    1992-01-01

    C-11 hydroxy ephedrine, introduced as the first clinically usable norepinephrine analogue, studies employing normal volunteers and patients with various cardiac disorders was found to valuable as a nonadreneric tracer. Simultaneously, animal studies been used to assess its use following ischemic injury in order to define neuronal damage. Current research focuses on the comparison of C-11 hydroxyephedrine with other neurotransmitters such as C-11 epinephrine and C-11 threohydroxyephedrine. Epinephrine is primarily stored in vesicles of the nerve terminal, while threo-hydroxyephedrine is only substrate to uptake I mechanism. Such a combination of radiotracers may allow the dissection of uptake I mechanism as well as vesicular storage. In parallel to the refinement of presynaptic tracers for the sympathetic nervous system, we are developing radiopharmaceuticals to delineate the adrenergic receptors in the heart. The combined evaluation of pre- and postsynaptic nerve function will improve our ability to identify abnormalides. We are currently developing a new radiosynthesis of the hydrophilic adrenergic receptor antagonist C-11 CGP-12177 which has been used by others for the visualization of adrenergic receptors in the heart. We are developing radiopharmaceuticals, for the delineation of presynaptic cholinergic nerve terminals. Derivatives of benzovesamicol have been labeled in our institution and are currently under investigation. The most promising agent is F-18 benzovesamicol (FEBOBV) which allows the visualization of parasympathetic nerve terminals in the canine heart as demonstrated by, preliminary PET data

  19. Parametric images evaluation of selected phases of the heart cycle with PET

    International Nuclear Information System (INIS)

    Just, U.; Will, E.; Beuthien Baumann, B.; Bredow, J.

    2002-01-01

    The standard evaluation of dynamic heart acquisitions with PET uses image data not corrected for heart wall movement. The evaluation of parametric data sets (Patlak Plot) was investigated for gated studies of selected heart phases (diastolic, systolic) and compared to the standard evaluation. Parametric images of selected heart phases have improved resolution. The values for metabolic rate are different for a ''normal'' and gated evaluation, up to 50% more for the systole compared to the normal one. (orig.)

  20. Myocardial blood flow and left ventricular functional reserve in hypertrophic cardiomyopathy: a {sup 13}NH{sub 3} gated PET study

    Energy Technology Data Exchange (ETDEWEB)

    Sciagra, Roberto; Calabretta, Raffaella; Passeri, Alessandro; Castello, Angelo; Pupi, Alberto [University of Florence, Nuclear Medicine Unit, Department of Experimental and Clinical Biomedical Sciences ' ' Mario Serio' ' , Florence (Italy); Cipollini, Fabrizio [University of Florence, Department of Statistics, Florence (Italy); Cecchi, Franco; Olivotto, Iacopo [Careggi University Hospital, Referral Centre for Myocardial Diseases, Florence (Italy)

    2017-05-15

    Ischemia in hypertrophic cardiomyopathy (HCM) is caused by coronary microvascular dysfunction (CMD), which is detected by measuring myocardial blood flow (MBF) with PET. Whether CMD may be associated with ischemic left ventricular (LV) dysfunction is unclear. We therefore assessed LV ejection fraction (EF) reserve in HCM patients undergoing dipyridamole (Dip) PET. Resting and stress {sup 13}NH{sub 3} dynamic as well as gated PET were performed in 34 HCM patients. Segmental MBF and transmural perfusion gradient (TPG = subendocardial / subepicardial MBF) were assessed. LVEF reserve was considered abnormal if Dip LVEF decreased more than 5 units as compared to rest. Eighteen patients had preserved (group A) and 16 abnormal LVEF reserve (group B; range -7 to -32). Group B patients had greater wall thickness than group A, but resting volumes, LVEF, resting and Dip MBF, and myocardial flow reserve were similar. Group B had slightly higher summed stress score and summed difference score in visual analysis than group A, and a significantly higher summed stress wall motion score. In group B, resting TPG was slightly lower (1.31 ± 0.29 vs. 1.37 ± 0.34, p <0.05), and further decreased after Dip, whilst in group A it increased (B = 1.20 ± 0.39, p < 0.0001 vs. rest and vs. A = 1.40 ± 0.43). The number of segments per patient with TPG <1 was higher than in group A (p < 0.001) and was a significant predictor of impaired LVEF reserve (OR 1.86, p < 0.02), together with wall thickness (OR 1.3, p < 0.02). Abnormal LVEF response is common in HCM patients following Dip, and is related to abnormal TPG, suggesting that subendocardial ischemia might occur under Dip and cause transient LV dysfunction. Although in vivo this effect may be hindered by the adrenergic drive associated with effort, these findings may have relevance in understanding exercise limitation and heart failure symptoms in HCM. (orig.)

  1. MRI-assisted PET motion correction for neurologic studies in an integrated MR-PET scanner.

    Science.gov (United States)

    Catana, Ciprian; Benner, Thomas; van der Kouwe, Andre; Byars, Larry; Hamm, Michael; Chonde, Daniel B; Michel, Christian J; El Fakhri, Georges; Schmand, Matthias; Sorensen, A Gregory

    2011-01-01

    Head motion is difficult to avoid in long PET studies, degrading the image quality and offsetting the benefit of using a high-resolution scanner. As a potential solution in an integrated MR-PET scanner, the simultaneously acquired MRI data can be used for motion tracking. In this work, a novel algorithm for data processing and rigid-body motion correction (MC) for the MRI-compatible BrainPET prototype scanner is described, and proof-of-principle phantom and human studies are presented. To account for motion, the PET prompt and random coincidences and sensitivity data for postnormalization were processed in the line-of-response (LOR) space according to the MRI-derived motion estimates. The processing time on the standard BrainPET workstation is approximately 16 s for each motion estimate. After rebinning in the sinogram space, the motion corrected data were summed, and the PET volume was reconstructed using the attenuation and scatter sinograms in the reference position. The accuracy of the MC algorithm was first tested using a Hoffman phantom. Next, human volunteer studies were performed, and motion estimates were obtained using 2 high-temporal-resolution MRI-based motion-tracking techniques. After accounting for the misalignment between the 2 scanners, perfectly coregistered MRI and PET volumes were reproducibly obtained. The MRI output gates inserted into the PET list-mode allow the temporal correlation of the 2 datasets within 0.2 ms. The Hoffman phantom volume reconstructed by processing the PET data in the LOR space was similar to the one obtained by processing the data using the standard methods and applying the MC in the image space, demonstrating the quantitative accuracy of the procedure. In human volunteer studies, motion estimates were obtained from echo planar imaging and cloverleaf navigator sequences every 3 s and 20 ms, respectively. Motion-deblurred PET images, with excellent delineation of specific brain structures, were obtained using these 2 MRI

  2. Some views about PET technique establish and development

    International Nuclear Information System (INIS)

    Huang Zuhan

    2001-01-01

    About 2100 patients had been performed in Nanfang PET center since its establish in November, 1999. The clinical practice showed that the positron emission tomography (PET) had unique value for the diagnosis of malignancy, cardiac coronal artery disease, myocardium viability and for lesion localization of epilepsy and other cerebral function diseases. It had important impact to treatment of these diseases and improved the treatment outcomes of them. It also promoted the scientific studies and other correlative subjects and enhanced the station of nuclear medicine. Its integrative benefit was very great. In order to develop this technique more smoothly, authors would give the views on some questions such as how to look on PET images, its clinical value, its price and its cost-effectiveness. The authors would also give some proposal which could not be neglectable for establish of PET technique

  3. Assessment of biodistribution of 131-IPPA in cardiac and non-cardiac tissues in laboratory animals by imaging

    International Nuclear Information System (INIS)

    Moradkani, S.; Sadadi, F.; Matloubi, M.; Jalilian, A. R.; Shafaie, K.; Karimian, A. R.; Daneshvari, S.

    2007-01-01

    The main substrate of myocardial metabolism is fatty acids which constitutes the principal agent for myocardial consumption and provides almost 60-80% of the energy utilized by the heart in the resting state. Evaluation of cardiac metabolism is important for the assessment of some of cardiac disorders such as Ischemic Heart disease (IHD), cardiomyopathy (functional disorders) and Hypertensive cardiac disorders. Today, almost in all of the developed countries, PET is the first step for diagnosis and assessment of cardiac metabolic disorders. It is, however, too expensive to be used in all centers and are not available in all countries. In this regards, 123-IPPA was introduced as a substitute of PET system for evaluation of cardiac function (metabolism) and it is a complementary method for other Para-clinical methods. We decided to have a preliminary study on IPPA and due to the lack of 123-I, we had to use 131-I. The labeling of IPPA by 131-I, purification and sterilization of 131-1PPA done by the Chemistry Group of Cyclotron Ward and the bio-kinetic and imaging of rat, mice (Laboratory Animals) were performed in the Nuclear Medicine Group. After injection of a proper dose of this radiotracer, the imaging was performed in an appropriate time. In our first images, there were intensive accumulation of tracer in animals' thyroid glands, though after the intake of Lugol solution, the thyroid did not appear and we had a number of excellent images of animal heart that was the target organ

  4. Scintigraphic assessment of heterotopic cardiac transplants

    International Nuclear Information System (INIS)

    Wilson, M.A.; Kahn, D.R.

    1981-01-01

    Patients receiving heterotopic (''piggyback'') cardiac transplants, when the patient's own and transplanted donor hearts are connected in parallel, present special problems in determining their relative contributions to total cardiac function. Three patients who had transplants because of intractable heart failure were studied using first pass and gated equilibrium technetium-99m-labeled blood pool scintigraphy. In one patient, thallium-201 myocardial perfusion scans were obtained. These nuclear cardiology techniques provided anatomic and functional information noninvasively that proved helpful in patient management

  5. Electrocardiographic-gated dual-isotope simultaneous acquisition SPECT using 18F-FDG and 99mTc-sestamibi to assess myocardial viability and function in a single study

    International Nuclear Information System (INIS)

    Matsunari, Ichiro; Matsudaira, Masamichi; Hisada, Kinichi; Kanayama, Sugako; Yoneyama, Tatsuya; Nakajima, Kenichi; Taki, Junichi; Tonami, Norihisa; Nekolla, Stephan G.

    2005-01-01

    Dual-isotope simultaneous acquisition single-photon emission computed tomography (DISA SPECT) with 18 F-fluorodeoxyglucose (FDG) and 99m Tc-sestamibi appears attractive for the detection of viable myocardium because it permits simultaneous assessment of glucose utilisation and perfusion. Another potential benefit of this approach is that the measurement of left ventricular (LV) function may be possible by ECG gating. The aim of this study was to test the hypothesis that both myocardial viability and LV function can be assessed by a single ECG-gated 18 F-FDG/ 99m Tc-sestamibi DISA SPECT study, based on comparison with 18 F-FDG/ 13 N-ammonia positron emission tomography (PET) and magnetic resonance imaging (MRI) as reference techniques. Thirty-three patients with prior myocardial infarction underwent ECG-gated 18 F-FDG/ 99m Tc-sestamibi DISA SPECT and 18 F-FDG/ 13 N-ammonia PET on a single day. Of these, 25 patients also underwent cine-MRI to assess LV function. The LV myocardium was divided into nine regions, and each region was classified as viable or scar using a semiquantitative visual scoring system as well as quantitative analysis. The global and regional LV function measured by gated SPECT was compared with the results of MRI. There was good agreement in respect of viability (90-96%, κ0.74-0.85) between DISA SPECT and PET by either visual or quantitative analysis. Furthermore, although both global and regional LV function measured by gated SPECT agreed with those by MRI, 99m Tc-sestamibi showed a closer correlation with MRI than did 18 F-FDG. In conclusion, ECG-gated DISA SPECT provides information on myocardial viability, as well as global and regional LV function, similar to that obtained by PET and MRI. (orig.)

  6. Pulmonary capillary wedge pressure, as inferred from lung areas in gated blood-pool scintigrams: concise communication

    International Nuclear Information System (INIS)

    Urbina, A.; Okada, R.D.; Palacios, I.; Osbakken, M.; Strauss, H.W.

    1981-01-01

    To determine whether the apex-to-base distribution of pulmonary blood volume, as obtained from gated cardiac blood-pool scans, could be used as a noninvasive method to estimate mean pulmonary capillary wedge pressure (PCWP), gated blood-pool scans were analyzed in 77 patients who also had PCWP measurements at cardiac catheterization. Ten of these patients had gated cardiac blood-pool scans and PCWP measurements both at rest and during exercise. The apex-to-base distribution of pulmonary blood volume was determined from the end-systolic frame of the left anterior oblique view by placing equal-sized regions of interest over the apex and base of the right lung. The ratio of apex counts over base counts (A/B ratio) was considered abnormal if greater than unity. The mean A/B ratio was 1.15 +/- 0.27 (1 s.d.) for the 32 studies associated with an abnormal mean PCWP (greater than 12 mm Hg). The mean A/B ratio was 0.85 +/- 0.23 for the 55 studies associated with a normal mean PCWP (p less than 0.01 comparing normal group with abnormal). The sensitivity of the A/B ratio for a mean PCWP greater than 12 mm Hg was 81%R (26/32). The specificity of the A/B ratio for a mean PCWP greater than or equal to 12 mm Hg was 89% (49/55). Thus, noninvasive determination of the pulmonary apex-to-base ratio from gated cardiac blood-pool scans appears to differentiate subjects with normal and abnormal mean pulmonary capillary wedge pressures

  7. Electrocardiographic gating of list mode data with a positron emission tomography system that utilizes wobbling motion to achieve uniform sampling

    International Nuclear Information System (INIS)

    Gaeta, J.M.; Yerian, K.A.; Mullani, N.A.

    1986-01-01

    An interactive software package has been developed for gating of list mode data acquired with PET. The package supports: histogram displays (ie. for determining an acceptable beat interval length window), automatic rejection of beats outside the window, forward or backward gating capabilities, capability of specifying the position of the gating interval, and of the time interval within the list mode study to be reformatted. The interaction of PET wobble motion frequency and heart beat frequency may result in image non-uniformities (ringing artifacts), due to incomplete wobble sampling. Therefore, the reconstruction software incorporates a very simple scheme for correcting for the amount of time spent at each wobble position and allowing for the decay of short lived isotopes such as Rubidium-82 (Rb-82). Rb-82 myocardial uptake images free of non-uniformity artifacts and quantitatively accurate have been reconstructed for 10 different dog studies, and 8 patient studies. Multi-slice frames at discrete portions of the heart cycle (i.e. End Diastole) and multi-gated sequences for cine display have been produced

  8. The utility of cardiac CT beyond the assessment of suspected coronary artery disease

    Energy Technology Data Exchange (ETDEWEB)

    Kakouros, N. [Johns Hopkins Hospital, Baltimore, MD (United States); Giles, J.; Crundwell, N.B. [Conquest Hospital, St Leonards-on-Sea, East Sussex (United Kingdom); McWilliams, E.T.M., E-mail: eric.mcwilliams@esht.nhs.uk [Conquest Hospital, St Leonards-on-Sea, East Sussex (United Kingdom)

    2012-07-15

    Extensive work has been done over recent years to improve the spatial and temporal resolution of electrocardiogram (ECG)-gated cardiac computed tomography (CT). Advances in both hardware and software analysis have enabled the development of non-invasive coronary angiography. However, these high-quality examinations lend themselves to multiple additional applications beyond coronary angiography. In this review, we illustrate and discuss some established and some emerging applications of ECG-gated cardiac CT beyond the assessment of suspected coronary disease, particularly in light of recent recommendations on the appropriate use of this technology.

  9. The utility of cardiac CT beyond the assessment of suspected coronary artery disease

    International Nuclear Information System (INIS)

    Kakouros, N.; Giles, J.; Crundwell, N.B.; McWilliams, E.T.M.

    2012-01-01

    Extensive work has been done over recent years to improve the spatial and temporal resolution of electrocardiogram (ECG)-gated cardiac computed tomography (CT). Advances in both hardware and software analysis have enabled the development of non-invasive coronary angiography. However, these high-quality examinations lend themselves to multiple additional applications beyond coronary angiography. In this review, we illustrate and discuss some established and some emerging applications of ECG-gated cardiac CT beyond the assessment of suspected coronary disease, particularly in light of recent recommendations on the appropriate use of this technology.

  10. Potential Applications of PET/MR Imaging in Cardiology.

    Science.gov (United States)

    Ratib, Osman; Nkoulou, René

    2014-06-01

    Recent advances in hybrid PET/MR imaging have opened new perspectives for cardiovascular applications. Although cardiac MR imaging has gained wider adoption for routine clinical applications, PET images remain the reference in many applications for which objective analysis of metabolic and physiologic parameters is needed. In particular, in cardiovascular diseases-more specifically, coronary artery disease-the use of quantitative and measurable parameters in a reproducible way is essential for the management of therapeutic decisions and patient follow-up. Functional MR images and dynamic assessment of myocardial perfusion from transit of intravascular contrast medium can provide useful criteria for identifying areas of decreased myocardial perfusion or for assessing tissue viability from late contrast enhancement of scar tissue. PET images, however, will provide more quantitative data on true tissue perfusion and metabolism. Quantitative myocardial flow can also lead to accurate assessment of coronary flow reserve. The combination of both modalities will therefore provide complementary data that can be expected to improve the accuracy and reproducibility of diagnostic procedures. But the true potential of hybrid PET/MR imaging may reside in applications beyond the domain of coronary artery disease. The combination of both modalities in assessment of other cardiac diseases such as inflammation and of other systemic diseases can also be envisioned. It is also predicted that the 2 modalities combined could help characterize atherosclerotic plaques and differentiate plaques with a high risk of rupture from stable plaques. In the future, the development of new tracers will also open new perspectives in evaluating myocardial remodeling and in assessing the kinetics of stem cell therapy in myocardial infarction. New tracers will also provide new means for evaluating alterations in cardiac innervation, angiogenesis, and even the assessment of reporter gene technologies

  11. MR-assisted PET Motion Correction for eurological Studies in an Integrated MR-PET Scanner

    Science.gov (United States)

    Catana, Ciprian; Benner, Thomas; van der Kouwe, Andre; Byars, Larry; Hamm, Michael; Chonde, Daniel B.; Michel, Christian J.; El Fakhri, Georges; Schmand, Matthias; Sorensen, A. Gregory

    2011-01-01

    Head motion is difficult to avoid in long PET studies, degrading the image quality and offsetting the benefit of using a high-resolution scanner. As a potential solution in an integrated MR-PET scanner, the simultaneously acquired MR data can be used for motion tracking. In this work, a novel data processing and rigid-body motion correction (MC) algorithm for the MR-compatible BrainPET prototype scanner is described and proof-of-principle phantom and human studies are presented. Methods To account for motion, the PET prompts and randoms coincidences as well as the sensitivity data are processed in the line or response (LOR) space according to the MR-derived motion estimates. After sinogram space rebinning, the corrected data are summed and the motion corrected PET volume is reconstructed from these sinograms and the attenuation and scatter sinograms in the reference position. The accuracy of the MC algorithm was first tested using a Hoffman phantom. Next, human volunteer studies were performed and motion estimates were obtained using two high temporal resolution MR-based motion tracking techniques. Results After accounting for the physical mismatch between the two scanners, perfectly co-registered MR and PET volumes are reproducibly obtained. The MR output gates inserted in to the PET list-mode allow the temporal correlation of the two data sets within 0.2 s. The Hoffman phantom volume reconstructed processing the PET data in the LOR space was similar to the one obtained processing the data using the standard methods and applying the MC in the image space, demonstrating the quantitative accuracy of the novel MC algorithm. In human volunteer studies, motion estimates were obtained from echo planar imaging and cloverleaf navigator sequences every 3 seconds and 20 ms, respectively. Substantially improved PET images with excellent delineation of specific brain structures were obtained after applying the MC using these MR-based estimates. Conclusion A novel MR-based MC

  12. PET and MR imaging: the odd couple or a match made in heaven?

    Science.gov (United States)

    Catana, Ciprian; Guimaraes, Alexander R; Rosen, Bruce R

    2013-05-01

    PET and MR imaging are modalities routinely used for clinical and research applications. Integrated scanners capable of acquiring PET and MR imaging data in the same session, sequentially or simultaneously, have recently become available for human use. In this article, we describe some of the technical advances that allowed the development of human PET/MR scanners; briefly discuss methodologic challenges and opportunities provided by this novel technology; and present potential oncologic, cardiac, and neuropsychiatric applications. These examples range from studies that might immediately benefit from PET/MR to more advanced applications on which future development might have an even broader impact.

  13. Measurement of left-to-right shunts by gated radionuclide angiography: concise communication

    International Nuclear Information System (INIS)

    Rigo, P.; Chevigne, M.

    1982-01-01

    Gated cardiac blood-pool scans allow comparison of left- and right-ventricular stroke volume. We have applied these measurements to the quantification of left-to-right shunts (QP/QS) in nine patients with atrial septal defects, one patients with partial anomalous pulmonary venous return, four patients with ventricular septal defects, and two patients with patent ductus arteriosus. None of these patients had combined lesions. QP/QS was measured as the right-ventricular (RV) stroke counts divided by the left-ventricular (LV) stroke counts and as the LV stroke counts divided by the RV stroke counts in patients with RV and LV diastolic volume overload respectively. All patients had also QP/QS measurements by oximetry and first-pass radionuclide angiography. The stroke-count measurements indicated the overloaded ventricle in all patients. QP/QS determined by equilibrium gated studies correlated well with those obtained by oximetry (r . 0.79). Reproducibility of the equilibrium measurements was good. We conclude that gated cardiac blood-pool scans can measure left-to-right shunts and can distinguish between shunts with RV and LV volume overload

  14. PET and MRI: The Odd Couple or a Match Made in Heaven?

    Science.gov (United States)

    Catana, Ciprian; Guimaraes, Alexander R.; Rosen, Bruce R.

    2013-01-01

    Positron emission tomography (PET) and magnetic resonance imaging (MRI) are imaging modalities routinely used for clinical and research applications. Integrated scanners capable of acquiring PET and MRI data in the same imaging session, sequentially or simultaneously, have recently become available for human use. In this manuscript, we describe some of the technical advances that allowed the development of human PET/MR scanners, briefly discuss methodological challenges and opportunities provided by this novel technology and present potential oncologic, cardiac, and neuro-psychiatric applications. These examples range from studies that might immediately benefit from PET/MR to more advanced applications where future development might have an even broader impact. PMID:23492887

  15. 'Motion frozen' quantification and display of myocardial perfusion gated SPECT

    International Nuclear Information System (INIS)

    Slomka, P.J.; Hurwitz, G.A.; Baddredine, M.; Baranowski, J.; Aladl, U.E.

    2002-01-01

    Aim: Gated SPECT imaging incorporates both functional and perfusion information of the left ventricle (LV). However perfusion data is confounded by the effect of ventricular motion. Most existing quantification paradigms simply add all gated frames and then proceed to extract the perfusion information from static images, discarding the effects of cardiac motion. In an attempt to improve the reliability and accuracy of cardiac SPECT quantification we propose to eliminate the LV motion prior to the perfusion quantification via automated image warping algorithm. Methods: A pilot series of 14 male and 11 female gated stress SPECT images acquired with 8 time bins have been co-registered to the coordinates of the 3D normal templates. Subsequently the LV endo and epi-cardial 3D points (300-500) were identified on end-systolic (ES) and end-diastolic (ED) frames, defining the ES-ED motion vectors. The nonlinear image warping algorithm (thin-plate-spline) was then applied to warp end-systolic frame was onto the end-diastolic frames using the corresponding ES-ED motion vectors. The remaining 6 intermediate frames were also transformed to the ED coordinates using fractions of the motion vectors. Such warped images were then summed to provide the LV perfusion image in the ED phase but with counts from the full cycle. Results: The identification of the ED/ES corresponding points was successful in all cases. The corrected displacement between ED and ES images was up to 25 mm. The summed images had the appearance of the ED frames but have been much less noisy since all the counts have been used. The spatial resolution of such images appeared higher than that of summed gated images, especially in the female scans. These 'motion frozen' images could be displayed and quantified as regular non-gated tomograms including polar map paradigm. Conclusions: This image processing technique may improve the effective image resolution of summed gated myocardial perfusion images used for

  16. Hybrid ECG-gated versus non-gated 512-slice CT angiography of the aorta and coronary artery: image quality and effect of a motion correction algorithm.

    Science.gov (United States)

    Lee, Ji Won; Kim, Chang Won; Lee, Geewon; Lee, Han Cheol; Kim, Sang-Pil; Choi, Bum Sung; Jeong, Yeon Joo

    2018-02-01

    Background Using the hybrid electrocardiogram (ECG)-gated computed tomography (CT) technique, assessment of entire aorta, coronary arteries, and aortic valve can be possible using single-bolus contrast administration within a single acquisition. Purpose To compare the image quality of hybrid ECG-gated and non-gated CT angiography of the aorta and evaluate the effect of a motion correction algorithm (MCA) on coronary artery image quality in a hybrid ECG-gated aorta CT group. Material and Methods In total, 104 patients (76 men; mean age = 65.8 years) prospectively randomized into two groups (Group 1 = hybrid ECG-gated CT; Group 2 = non-gated CT) underwent wide-detector array aorta CT. Image quality, assessed using a four-point scale, was compared between the groups. Coronary artery image quality was compared between the conventional reconstruction and motion correction reconstruction subgroups in Group 1. Results Group 1 showed significant advantages over Group 2 in aortic wall, cardiac chamber, aortic valve, coronary ostia, and main coronary arteries image quality (all P ECG-gated CT significantly improved the heart and aortic wall image quality and the MCA can further improve the image quality and interpretability of coronary arteries.

  17. Assessment of left ventricular function by electrocardiogram-gated myocardial single photon emission computed tomography using quantitative gated single photon emission computed tomography software

    International Nuclear Information System (INIS)

    Morita, Koichi; Adachi, Itaru; Konno, Masanori

    1999-01-01

    Electrocardiogram (ECG)-gated myocardial single photon emission computed tomography (SPECT) can assess left ventricular (LV) perfusion and function easily using quantitative gated SPECT (QGS) software. ECG-gated SPECT was performed in 44 patients with coronary artery disease under post-stress and resting conditions to assess the values of LV functional parameters, by comparison to LV ejection fraction derived from gated blood pool scan and myocardial characteristics. A good correlation was obtained between ejection fraction using QGS and that using cardiac blood pool scan (r=0.812). Some patients with myocardial ischemia had lower ejection fraction under post-stress compared to resting conditions, indicating post-stress LV dysfunction. LV wall motion and wall thickening were significantly impaired in ischemic and infarcted myocardium, and the degree of abnormality in the infarcted areas was greater than in the ischemia area. LV functional parameters derived using QGS were useful to assess post-stress LV dysfunction and myocardial viability. In conclusion, ECG-gated myocardial SPECT permits simultaneous quantitative assessment of myocardial perfusion and function. (author)

  18. High-precision γ -ray spectroscopy of the cardiac PET imaging isotope 82Rb and its impact on dosimetry

    Science.gov (United States)

    Nino, M. N.; McCutchan, E. A.; Smith, S. V.; Lister, C. J.; Greene, J. P.; Carpenter, M. P.; Muench, L.; Sonzogni, A. A.; Zhu, S.

    2016-02-01

    82Rb is a positron-emitting isotope used in cardiac positron emission tomography (PET) imaging which has been reported to deliver a significantly lower effective radiation dose than analogous imaging isotopes like 201Tl and 99 mTc sestamibi. High-quality β -decay data are essential to accurately appraise the total dose received by the patients. A source of 82Sr was produced at the Brookhaven Linac Isotope Producer (BLIP), transported to Argonne National Laboratory, and studied with the Gammasphere facility. Significant revisions have been made to the level scheme of 82Kr including 12 new levels, 50 new γ -ray transitions, and the determination of many new spin assignments through angular correlations. These new high-quality data allow a precise reappraisal of the β -decay strength function and thus the consequent dose received by patients.

  19. TH-E-202-00: PET for Radiation Therapy

    International Nuclear Information System (INIS)

    2016-01-01

    PET/CT is a very important imaging tool in the management of oncology patients. PET/CT has been applied for treatment planning and response evaluation in radiation therapy. This educational session will discuss: Pitfalls and remedies in PET/CT imaging for RT planning The use of hypoxia PET imaging for radiotherapy PET for tumor response evaluation The first presentation will address the issue of mis-registration between the CT and PET images in the thorax and the abdomen. We will discuss the challenges of respiratory gating and introduce an average CT technique to improve the registration for dose calculation and image-guidance in radiation therapy. The second presentation will discuss the use of hypoxia PET Imaging for radiation therapy. We will discuss various hypoxia radiotracers, the choice of clinical acquisition protocol (in particular a single late static acquisition versus a dynamic acquisition), and the compartmental modeling with different transfer rate constants explained. We will demonstrate applications of hypoxia imaging for dose escalation/de-escalation in clinical trials. The last presentation will discuss the use of PET/CT for tumor response evaluation. We will discuss anatomic response assessment vs. metabolic response assessment, visual evaluation and semi-quantitative evaluation, and limitations of current PET/CT assessment. We will summarize clinical trials using PET response in guiding adaptive radiotherapy. Finally, we will summarize recent advancements in PET/CT radiomics and non-FDG PET tracers for response assessment. Learning Objectives: Identify the causes of mis-registration of CT and PET images in PET/CT, and review the strategies to remedy the issue. Understand the basics of PET imaging of tumor hypoxia (radiotracers, how PET measures the hypoxia selective uptake, imaging protocols, applications in chemo-radiation therapy). Understand the basics of dynamic PET imaging, compartmental modeling and parametric images. Understand the

  20. TH-E-202-00: PET for Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2016-06-15

    PET/CT is a very important imaging tool in the management of oncology patients. PET/CT has been applied for treatment planning and response evaluation in radiation therapy. This educational session will discuss: Pitfalls and remedies in PET/CT imaging for RT planning The use of hypoxia PET imaging for radiotherapy PET for tumor response evaluation The first presentation will address the issue of mis-registration between the CT and PET images in the thorax and the abdomen. We will discuss the challenges of respiratory gating and introduce an average CT technique to improve the registration for dose calculation and image-guidance in radiation therapy. The second presentation will discuss the use of hypoxia PET Imaging for radiation therapy. We will discuss various hypoxia radiotracers, the choice of clinical acquisition protocol (in particular a single late static acquisition versus a dynamic acquisition), and the compartmental modeling with different transfer rate constants explained. We will demonstrate applications of hypoxia imaging for dose escalation/de-escalation in clinical trials. The last presentation will discuss the use of PET/CT for tumor response evaluation. We will discuss anatomic response assessment vs. metabolic response assessment, visual evaluation and semi-quantitative evaluation, and limitations of current PET/CT assessment. We will summarize clinical trials using PET response in guiding adaptive radiotherapy. Finally, we will summarize recent advancements in PET/CT radiomics and non-FDG PET tracers for response assessment. Learning Objectives: Identify the causes of mis-registration of CT and PET images in PET/CT, and review the strategies to remedy the issue. Understand the basics of PET imaging of tumor hypoxia (radiotracers, how PET measures the hypoxia selective uptake, imaging protocols, applications in chemo-radiation therapy). Understand the basics of dynamic PET imaging, compartmental modeling and parametric images. Understand the

  1. Brain 18F-FDG, 18F-florbtaben PET/CT, 123I-FP-CIT SPECT and cardiac 123I-MBG imaging for diagnosis of a 'cerebral type' of Lewy Body disease

    International Nuclear Information System (INIS)

    Gucht, Axel Van Der; Bélissant, Ophélie; Rabu, Corenti; Cottereau, Anne-Ségolène; Evangelista, Eva; Chalaye, Julia; Bonnot-Lours, Sophie; Fénelon, Gilles; Itti, Emmanuel; De Langavant, Laurent Cleret

    2016-01-01

    A 67-year-old man was referred for fluctuating neuropsychiatric symptoms, featuring depression, delirious episodes, recurrent visual hallucinations and catatonic syndrome associated with cognitive decline. No parkinsonism was found clinically even under neuroleptic treatment. 18 F-FDG PET/CT showed hypometabolism in the posterior associative cortex including the occipital cortex, suggesting Lewy body dementia, but 123 I-FP-CIT SPECT was normal and cardiac 123 I-MIBG imaging showed no signs of sympathetic denervation. Alzheimer's disease was excluded by a normal 18 F-florbetaben PET/CT. This report suggests a rare case of α-synucleinopathy without brainstem involvement, referred to as 'cerebral type' of Lewy body disease

  2. Simulation study of LYSO crystal pixels for In-Beam TOF-PET prototype

    International Nuclear Information System (INIS)

    Chen Ze; Hu Zhengguo; Chen Jinda; Zhang Xiuling

    2014-01-01

    In-beam TOF-PET is currently the only feasible method implemented for in-situ and noninvasive monitoring of the precision of the treatment in highly conformal ion radiotherapy. It ensures the safety of patient and accurate implementation of treatment plan. Therefore, we intent to carry out the development of In-beam TOF-PET prototype, which is made of LYSO crystal, for ion radiotherapy. LYSO crystal has perfect properties such as high light yield, fast decay time, good energy and time resolution, which makes it a good candidate. In the development of positron emission tomography (PET) detectors, understanding and optimizing scintillator light collection and energy resolution is critical for achieving high performance, particularly when the design incorporates depth-of-interaction (DOI) encoding or time-of-flight information. Monte Carlo simulations play an important role in guiding research in detector designs and popular software such as Gate now include models of light transport in scintillators. This study uses Gate software to investigate the influence of crystal length and wrapping materials to the light collection. Accurate physical modeling of scintillation detection process, from scintillation light generation through detection, is devised and performed for varying detector attributes, such as the crystal pixel length, light yield, decay time, attenuation length and surface treatment. The dependence of light output and energy resolution is studied and compared with experiment results. The results show that LYSO pixel with length of 5 mm has better light yield and energy resolution, meanwhile prove that it is possible to accurately simulate the light output using Gate. (authors)

  3. Gated equilibrium bloodpool scintigraphy

    International Nuclear Information System (INIS)

    Reinders Folmer, S.C.C.

    1981-01-01

    This thesis deals with the clinical applications of gated equilibrium bloodpool scintigraphy, performed with either a gamma camera or a portable detector system, the nuclear stethoscope. The main goal has been to define the value and limitations of noninvasive measurements of left ventricular ejection fraction as a parameter of cardiac performance in various disease states, both for diagnostic purposes as well as during follow-up after medical or surgical intervention. Secondly, it was attempted to extend the use of the equilibrium bloodpool techniques beyond the calculation of ejection fraction alone by considering the feasibility to determine ventricular volumes and by including the possibility of quantifying valvular regurgitation. In both cases, it has been tried to broaden the perspective of the observations by comparing them with results of other, invasive and non-invasive, procedures, in particular cardiac catheterization, M-mode echocardiography and myocardial perfusion scintigraphy. (Auth.)

  4. Intracellular calcium modulation of voltage-gated sodium channels in ventricular myocytes

    NARCIS (Netherlands)

    Casini, Simona; Verkerk, Arie O.; van Borren, Marcel M. G. J.; van Ginneken, Antoni C. G.; Veldkamp, Marieke W.; de Bakker, Jacques M. T.; Tan, Hanno L.

    2009-01-01

    AIMS: Cardiac voltage-gated sodium channels control action potential (AP) upstroke and cell excitability. Intracellular calcium (Ca(i)(2+)) regulates AP properties by modulating various ion channels. Whether Ca(i)(2+) modulates sodium channels in ventricular myocytes, is unresolved. We studied

  5. FDG-PET identification of infected pulmonary artery conduit following tetralogy of fallot (TOF) repair

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yu Yang; Williams, Hadyn; Pucar, Darko [Dept. of Radiology, Medical College of Georgia, Augusta (United States)

    2017-03-15

    Tetralogy of Fallot (TOF) is one of the most common forms of cyanotic congenital heart disease usually managed by serial surgical repairs. The repaired prosthetic valve or conduit is susceptible to life-threatening infection. FDG-PET is an effective alternative to evaluate the source of infection when other examinations are inconclusive. We report an unusual case of an infected pulmonary artery conduit after TOF repair although the echocardiogram was negative for vegetation, which was later confirmed by surgery and pathology. The case highlights the role of FDG-PET as a problem-solving tool for potential endocarditis and cardiac device infection cases after complex cardiac surgery.

  6. FDG-PET identification of infected pulmonary artery conduit following tetralogy of fallot (TOF) repair

    International Nuclear Information System (INIS)

    Zhang, Yu Yang; Williams, Hadyn; Pucar, Darko

    2017-01-01

    Tetralogy of Fallot (TOF) is one of the most common forms of cyanotic congenital heart disease usually managed by serial surgical repairs. The repaired prosthetic valve or conduit is susceptible to life-threatening infection. FDG-PET is an effective alternative to evaluate the source of infection when other examinations are inconclusive. We report an unusual case of an infected pulmonary artery conduit after TOF repair although the echocardiogram was negative for vegetation, which was later confirmed by surgery and pathology. The case highlights the role of FDG-PET as a problem-solving tool for potential endocarditis and cardiac device infection cases after complex cardiac surgery

  7. Thin-section CT of lung without ECG gating: 64-detector row CT can markedly reduce cardiac motion artifact which can simulate lung lesions

    International Nuclear Information System (INIS)

    Yanagawa, Masahiro; Tomiyama, Noriyuki; Sumikawa, Hiromitsu; Inoue, Atsuo; Daimon, Tadahisa; Honda, Osamu; Mihara, Naoki; Johkoh, Takeshi; Nakamura, Hironobu

    2009-01-01

    Purpose: Motion artifacts, which can mimic thickened bronchial wall and the cystic appearance of bronchiectasis, constitute a potential pitfall in the diagnosis of interstitial or bronchial disease. Therefore, purpose of our study was to evaluate whether 64-detector row CT (64-MDCT) enables a reduction in respiratory or cardiac motion artifacts in the lung area on thin-section CT without ECG gating, and to examine the correlation between cardiac motion artifact and heart rate. Materials and methods: Thirty-two patients with suspected diffuse lung disease, who underwent both 8- and 64-MDCT (gantry rotation time, 0.5 and 0.4 s, respectively), were included. The heart rates of an additional 155 patients were measured (range, 48-126 beats per minute; mean, 76 beats per minute) immediately prior to 64-MDCT, and compared to the degree of cardiac motion artifact. Two independent observers evaluated the following artifacts on a monitor without the knowledge of relevant clinical information: (1) artifacts on 8- and 64-MDCT images with 1.25-mm thickness and those on 64-MDCT images with 0.625-mm thickness in 32 patients; and (2) artifacts on 64-MDCT images with 0.625-mm thickness in 155 patients. Results: Interobserver agreement was good in evaluating artifacts on 8-MDCT images with 1.25-mm thickness (weighted Kappa test, κ = 0.61-0.71), and fair or poor in the other evaluations (κ < 0.31). Two observers stated that cardiac motion artifacts were more significant on 8-MDCT than on 64-MDCT in all 32 patients. Statistically significant differences were found at various checkpoints only in comparing artifacts between 8- and 64-MDCT for 1.25-mm thickness (Wilcoxon's signed-rank test, p < 0.0017). Cardiac motion artifacts on 64-MDCT had no significant correlation with heart rate (Spearman's correlation coefficient by rank test). Conclusion: The high temporal resolution of 64-MDCT appears to reduce cardiac motion artifact that can affect thin-section scans of the lung parenchyma

  8. Thin-section CT of lung without ECG gating: 64-detector row CT can markedly reduce cardiac motion artifact which can simulate lung lesions

    Energy Technology Data Exchange (ETDEWEB)

    Yanagawa, Masahiro [Department of Radiology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita-city, Osaka 565-0871 (Japan)], E-mail: m-yanagawa@radiol.med.osaka-u.ac.jp; Tomiyama, Noriyuki; Sumikawa, Hiromitsu; Inoue, Atsuo [Department of Radiology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita-city, Osaka 565-0871 (Japan); Daimon, Tadahisa [Department of Radiology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita-city, Osaka 565-0871 (Japan); Department of Medicine, Division of Pulmonary Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498 (Japan); Honda, Osamu [Department of Radiology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita-city, Osaka 565-0871 (Japan); Mihara, Naoki [Department of Radiology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita-city, Osaka 565-0871 (Japan); Department of Radiology, Osaka Advanced Medical Imaging Center, 5-20-1 Momoyamadai, Suita-city, Osaka 565-0854 (Japan); Johkoh, Takeshi [Department of Radiology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita-city, Osaka 565-0871 (Japan); Department of Medical Physics, Osaka University Graduate School of Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita-city, Osaka 565-0871 (Japan); Nakamura, Hironobu [Department of Radiology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita-city, Osaka 565-0871 (Japan)

    2009-01-15

    Purpose: Motion artifacts, which can mimic thickened bronchial wall and the cystic appearance of bronchiectasis, constitute a potential pitfall in the diagnosis of interstitial or bronchial disease. Therefore, purpose of our study was to evaluate whether 64-detector row CT (64-MDCT) enables a reduction in respiratory or cardiac motion artifacts in the lung area on thin-section CT without ECG gating, and to examine the correlation between cardiac motion artifact and heart rate. Materials and methods: Thirty-two patients with suspected diffuse lung disease, who underwent both 8- and 64-MDCT (gantry rotation time, 0.5 and 0.4 s, respectively), were included. The heart rates of an additional 155 patients were measured (range, 48-126 beats per minute; mean, 76 beats per minute) immediately prior to 64-MDCT, and compared to the degree of cardiac motion artifact. Two independent observers evaluated the following artifacts on a monitor without the knowledge of relevant clinical information: (1) artifacts on 8- and 64-MDCT images with 1.25-mm thickness and those on 64-MDCT images with 0.625-mm thickness in 32 patients; and (2) artifacts on 64-MDCT images with 0.625-mm thickness in 155 patients. Results: Interobserver agreement was good in evaluating artifacts on 8-MDCT images with 1.25-mm thickness (weighted Kappa test, {kappa} = 0.61-0.71), and fair or poor in the other evaluations ({kappa} < 0.31). Two observers stated that cardiac motion artifacts were more significant on 8-MDCT than on 64-MDCT in all 32 patients. Statistically significant differences were found at various checkpoints only in comparing artifacts between 8- and 64-MDCT for 1.25-mm thickness (Wilcoxon's signed-rank test, p < 0.0017). Cardiac motion artifacts on 64-MDCT had no significant correlation with heart rate (Spearman's correlation coefficient by rank test). Conclusion: The high temporal resolution of 64-MDCT appears to reduce cardiac motion artifact that can affect thin-section scans of

  9. GATE Monte Carlo simulation of GE discovery 600 and a uniformity phantom

    Energy Technology Data Exchange (ETDEWEB)

    Sheen, Heesoon [Sungkyunkwan University, Seoul (Korea, Republic of); GE Healthcare Korea, Seoul (Korea, Republic of); Im, Kichun; Choi, Yong; Shin, Hanback [Sogang University, Seoul (Korea, Republic of); Han, Youngyih [Samsung Medical Center, Seoul (Korea, Republic of); Sungkyunkwan University, Seoul (Korea, Republic of); Chung, Kwangzoo; Cho, Junsang [Samsung Medical Center, Seoul (Korea, Republic of); Ahn, Sanghee [Sungkyunkwan University, Seoul (Korea, Republic of)

    2014-12-15

    GATE (Geant4 Application Tomography Emission) Monte Carlo simulations have been successful in the application of emission tomography for precise modeling of various physical processes. Most previous studies on Monte Carlo simulations have only involved performance assessments using virtual phantoms. Although that allows the performance of simulated positron emission tomography (PET) to be evaluated, it does not reflect the reality of practical conditions. This restriction causes substantial drawbacks in GATE simulations of real situations. To overcome the described limitation and to provide a method to enable simulation research relevant to clinically important issues, we conducted a GATE simulation using real data from a scanner rather than a virtual phantom and evaluated the scanner is performance. For that purpose, the system and the geometry of a commercial GE PET/ CT (computed tomography) scanner, BGO-based Discovery 600 (D600), was developed for the first time. The performance of the modeled PET system was evaluated by using the National Electrical Manufacturers Association NEMA NU 2-2007 protocols and results were compared with those of the reference data. The sensitivity, scatter fraction, noise-equivalent count rate (NECR), and resolution were estimated by using the protocol of the NEMA NU2-2007. Sensitivities were 9.01 cps/kBq at 0 cm and 9.43 cps/kBq at 10 cm. Scatter fractions were 39.5%. The NECR peak was 89.7 kcps at 14.7 kBq/cc. Resolutions were 4.8 mm in the transaxial plane and 5.9 mm in the axial plane at 1 cm, and 6.2 mm in the transaxial plane and 6.4 mm in the axial plane at 10 cm. The resolutions exceeded the limited value provided by the manufacturer. The uniformity phantom was simulated using the CT and the PET data. The output data in a ROOT format were converted and then reconstructed by using the C program and STIR (Software for Tomographic Image Reconstruction). The reconstructed images of the simulated uniformity phantom data had

  10. GATE Monte Carlo simulation of GE Discovery 600 and a uniformity phantom

    Science.gov (United States)

    Sheen, Heesoon; Im, Ki Chun; Choi, Yong; Shin, Hanback; Han, Youngyih; Chung, Kwangzoo; Cho, Junsang; Ahn, Sang Hee

    2014-12-01

    GATE (Geant4 Application Tomography Emission) Monte Carlo simulations have been successful in the application of emission tomography for precise modeling of various physical processes. Most previous studies on Monte Carlo simulations have only involved performance assessments using virtual phantoms. Although that allows the performance of simulated positron emission tomography (PET) to be evaluated, it does not reflect the reality of practical conditions. This restriction causes substantial drawbacks in GATE simulations of real situations. To overcome the described limitation and to provide a method to enable simulation research relevant to clinically important issues, we conducted a GATE simulation using real data from a scanner rather than a virtual phantom and evaluated the scanner is performance. For that purpose, the system and the geometry of a commercial GE PET/ CT (computed tomography) scanner, BGO-based Discovery 600 (D600), was developed for the first time. The performance of the modeled PET system was evaluated by using the National Electrical Manufacturers Association NEMA NU 2-2007 protocols and results were compared with those of the reference data. The sensitivity, scatter fraction, noise-equivalent count rate (NECR), and resolution were estimated by using the protocol of the NEMA NU2-2007. Sensitivities were 9.01 cps/kBq at 0 cm and 9.43 cps/kBq at 10 cm. Scatter fractions were 39.5%. The NECR peak was 89.7 kcps @ 14.7 kBq/cc. Resolutions were 4.8 mm in the transaxial plane and 5.9 mm in the axial plane at 1 cm, and 6.2 mm in the transaxial plane and 6.4 mm in the axial plane at 10 cm. The resolutions exceeded the limited value provided by the manufacturer. The uniformity phantom was simulated using the CT and the PET data. The output data in a ROOT format were converted and then reconstructed by using the C program and STIR (Software for Tomographic Image Reconstruction). The reconstructed images of the simulated uniformity phantom data had

  11. GATE Monte Carlo simulation of GE discovery 600 and a uniformity phantom

    International Nuclear Information System (INIS)

    Sheen, Heesoon; Im, Kichun; Choi, Yong; Shin, Hanback; Han, Youngyih; Chung, Kwangzoo; Cho, Junsang; Ahn, Sanghee

    2014-01-01

    GATE (Geant4 Application Tomography Emission) Monte Carlo simulations have been successful in the application of emission tomography for precise modeling of various physical processes. Most previous studies on Monte Carlo simulations have only involved performance assessments using virtual phantoms. Although that allows the performance of simulated positron emission tomography (PET) to be evaluated, it does not reflect the reality of practical conditions. This restriction causes substantial drawbacks in GATE simulations of real situations. To overcome the described limitation and to provide a method to enable simulation research relevant to clinically important issues, we conducted a GATE simulation using real data from a scanner rather than a virtual phantom and evaluated the scanner is performance. For that purpose, the system and the geometry of a commercial GE PET/ CT (computed tomography) scanner, BGO-based Discovery 600 (D600), was developed for the first time. The performance of the modeled PET system was evaluated by using the National Electrical Manufacturers Association NEMA NU 2-2007 protocols and results were compared with those of the reference data. The sensitivity, scatter fraction, noise-equivalent count rate (NECR), and resolution were estimated by using the protocol of the NEMA NU2-2007. Sensitivities were 9.01 cps/kBq at 0 cm and 9.43 cps/kBq at 10 cm. Scatter fractions were 39.5%. The NECR peak was 89.7 kcps at 14.7 kBq/cc. Resolutions were 4.8 mm in the transaxial plane and 5.9 mm in the axial plane at 1 cm, and 6.2 mm in the transaxial plane and 6.4 mm in the axial plane at 10 cm. The resolutions exceeded the limited value provided by the manufacturer. The uniformity phantom was simulated using the CT and the PET data. The output data in a ROOT format were converted and then reconstructed by using the C program and STIR (Software for Tomographic Image Reconstruction). The reconstructed images of the simulated uniformity phantom data had

  12. Phantom study on three-dimensional target volume delineation by PET/CT-based auto-contouring

    International Nuclear Information System (INIS)

    Zhang, Tiejiao; Sakaguchi, Yuichi; Mitsumoto, Katsuhiko; Mitsumoto, Tatsuya; Sasaki, Masayuki; Tachiya, Yosuke; Ohya, Nobuyoshi

    2010-01-01

    The aim of this study was to determine an appropriate threshold value for delineation of the target volume in positron emission tomography (PET)/CT and to investigate whether we could delineate a target volume by phantom studies. A phantom consisted of six spheres (φ10-37 mm) filled with 18 F solution. Data acquisition was performed PET/CT in non-motion and motion status with high 18 F solution and in non-motion status with low 18 F solution. In non-motion phantom experiments, we determined two types of threshold value, an absolute SUV (T SUV ) and a percentage of the maximum SUV (T % ). Delineation using threshold values was applied for all spheres and for selected large spheres (a diameter of 22 mm or larger). In motion phantom experiments, data acquisition was performed in a static mode (sPET) and a gated mode (gPET). CT scanning was performed with helical CT (HCT) and 4-dimentional CT (4DCT). The appropriate threshold values were aT % =27% and aT SUV =2.4 for all spheres, and sT % =30% and sT SUV =4.3 for selected spheres. For all spheres in sPET/HCT in motion, the delineated volumes were 84%-129% by the aT % and 34%-127% by the aT SUV . In gPET/4DCT in motion, the delineated volumes were 94-103% by the aT % and 51-131% by the aT SUV . For low radioactivity spheres, the delineated volumes were all underestimated. A threshold value of T % =27% was proposed for auto-contouring of lung tumors. Our results also suggested that the respiratory gated data acquisition should be performed in both PET and CT for target volume delineation. (author)

  13. Model-based image reconstruction for four-dimensional PET

    International Nuclear Information System (INIS)

    Li Tianfang; Thorndyke, Brian; Schreibmann, Eduard; Yang Yong; Xing Lei

    2006-01-01

    Positron emission tonography (PET) is useful in diagnosis and radiation treatment planning for a variety of cancers. For patients with cancers in thoracic or upper abdominal region, the respiratory motion produces large distortions in the tumor shape and size, affecting the accuracy in both diagnosis and treatment. Four-dimensional (4D) (gated) PET aims to reduce the motion artifacts and to provide accurate measurement of the tumor volume and the tracer concentration. A major issue in 4D PET is the lack of statistics. Since the collected photons are divided into several frames in the 4D PET scan, the quality of each reconstructed frame degrades as the number of frames increases. The increased noise in each frame heavily degrades the quantitative accuracy of the PET imaging. In this work, we propose a method to enhance the performance of 4D PET by developing a new technique of 4D PET reconstruction with incorporation of an organ motion model derived from 4D-CT images. The method is based on the well-known maximum-likelihood expectation-maximization (ML-EM) algorithm. During the processes of forward- and backward-projection in the ML-EM iterations, all projection data acquired at different phases are combined together to update the emission map with the aid of deformable model, the statistics is therefore greatly improved. The proposed algorithm was first evaluated with computer simulations using a mathematical dynamic phantom. Experiment with a moving physical phantom was then carried out to demonstrate the accuracy of the proposed method and the increase of signal-to-noise ratio over three-dimensional PET. Finally, the 4D PET reconstruction was applied to a patient case

  14. The evaluation of right ventricular performance using krypton-81m multiple-gated equilibrium cardiac blood pool scintigraphy

    International Nuclear Information System (INIS)

    Hosoi, Tsutomu

    1993-01-01

    Technetium-99m first pass angiography and multiple-gated equilibrium blood pool scintigraphy have been used for evaluating right ventricular performance, but both techniques have several methodologic limitations. The activity of kr-81m is exhaled during its transit through the lungs and residual activity in the left heart is negligible. Therefore, right heart study can be performed in the right anterior oblique position with optimal separation between the right ventricle and the right atrium. Thus, the author assessed right ventricular function using Kr-81m multiple-gated equilibrium cardiac blood pool scintigraphy in 40 patients with old myocardial infarction and 9 normal subjects. The patient group included 11 cases of inferior infarction with a significant stenosing lesion proximal to the origin of the right ventricular branch of the right coronary artery (group I), 11 cases of inferior infarction without a significant lesion in the proximal portion of the right coronary artery (group II) and 18 cases of anterior wall infarction (group III). The right ventricular ejection fraction (EF) was 45.6±9.8% in group I, 56.6±5.7% in group II, 55.6±4.4% in group III and 53.7±3.2% in the 9 normal subjects. There were no statistically significant differences among these 4 groups. However, right ventricular EF was significantly reduced in 5 group I patients who had hemodynamic evidence of right ventricular infarction (39.4±9.5%, P<0.01 vs group II, group III and normal subjects). No significant correlation was found between right and left ventricular EF or between right ventricular EF and wall motion abnormality of the interventricular septum. (author)

  15. FET-biosensor for cardiac troponin biomarker

    Directory of Open Access Journals (Sweden)

    Md Arshad Mohd Khairuddin

    2017-01-01

    Full Text Available Acute myocardial infarction or myocardial infarction (MI is a major health problem, due to diminished flow of blood to the heart, leads to higher rates of mortality and morbidity. The most specific markers for cardiac injury are cardiac troponin I (cTnI and cardiac troponin T (cTnT which have been considered as ‘gold standard’. Due to higher specificity, determination of the level of cardiac troponins became a predominant indicator for MI. Currently, field-effect transistor (FET-based biosensors have been main interest to be implemented in portable sensors with the ultimate application in point-of-care testing (POCT. In this paper, we review on the FET-based biosensor based on its principle of operation, integration with nanomaterial, surface functionalization as well as immobilization, and the introduction of additional gate (for ambipolar conduction on the device architecture for the detection of cardiac troponin I (cTnI biomarker.

  16. Robust real-time extraction of respiratory signals from PET list-mode data.

    Science.gov (United States)

    Salomon, Andre; Zhang, Bin; Olivier, Patrick; Goedicke, Andreas

    2018-05-01

    Respiratory motion, which typically cannot simply be suspended during PET image acquisition, affects lesions' detection and quantitative accuracy inside or in close vicinity to the lungs. Some motion compensation techniques address this issue via pre-sorting ("binning") of the acquired PET data into a set of temporal gates, where each gate is assumed to be minimally affected by respiratory motion. Tracking respiratory motion is typically realized using dedicated hardware (e.g. using respiratory belts and digital cameras). Extracting respiratory signalsdirectly from the acquired PET data simplifies the clinical workflow as it avoids to handle additional signal measurement equipment. We introduce a new data-driven method "Combined Local Motion Detection" (CLMD). It uses the Time-of-Flight (TOF) information provided by state-of-the-art PET scanners in order to enable real-time respiratory signal extraction without additional hardware resources. CLMD applies center-of-mass detection in overlapping regions based on simple back-positioned TOF event sets acquired in short time frames. Following a signal filtering and quality-based pre-selection step, the remaining extracted individual position information over time is then combined to generate a global respiratory signal. The method is evaluated using 7 measured FDG studies from single and multiple scan positions of the thorax region, and it is compared to other software-based methods regarding quantitative accuracy and statistical noise stability. Correlation coefficients around 90% between the reference and the extracted signal have been found for those PET scans where motion affected features such as tumors or hot regions were present in the PET field-of-view. For PET scans with a quarter of typically applied radiotracer doses, the CLMD method still provides similar high correlation coefficients which indicates its robustness to noise. Each CLMD processing needed less than 0.4s in total on a standard multi-core CPU

  17. Robust real-time extraction of respiratory signals from PET list-mode data

    Science.gov (United States)

    Salomon, André; Zhang, Bin; Olivier, Patrick; Goedicke, Andreas

    2018-06-01

    Respiratory motion, which typically cannot simply be suspended during PET image acquisition, affects lesions’ detection and quantitative accuracy inside or in close vicinity to the lungs. Some motion compensation techniques address this issue via pre-sorting (‘binning’) of the acquired PET data into a set of temporal gates, where each gate is assumed to be minimally affected by respiratory motion. Tracking respiratory motion is typically realized using dedicated hardware (e.g. using respiratory belts and digital cameras). Extracting respiratory signals directly from the acquired PET data simplifies the clinical workflow as it avoids handling additional signal measurement equipment. We introduce a new data-driven method ‘combined local motion detection’ (CLMD). It uses the time-of-flight (TOF) information provided by state-of-the-art PET scanners in order to enable real-time respiratory signal extraction without additional hardware resources. CLMD applies center-of-mass detection in overlapping regions based on simple back-positioned TOF event sets acquired in short time frames. Following a signal filtering and quality-based pre-selection step, the remaining extracted individual position information over time is then combined to generate a global respiratory signal. The method is evaluated using seven measured FDG studies from single and multiple scan positions of the thorax region, and it is compared to other software-based methods regarding quantitative accuracy and statistical noise stability. Correlation coefficients around 90% between the reference and the extracted signal have been found for those PET scans where motion affected features such as tumors or hot regions were present in the PET field-of-view. For PET scans with a quarter of typically applied radiotracer doses, the CLMD method still provides similar high correlation coefficients which indicates its robustness to noise. Each CLMD processing needed less than 0.4 s in total on a standard

  18. Gated myocardial SPECT using spatial and temporal filtering

    International Nuclear Information System (INIS)

    Hatton, R.L.; Hutton, B.F.; Kyme, A.Z.; Larcos, G.

    2002-01-01

    Full text: Standard protocols for examining myocardial perfusion and motion defects involve the use of gated SPECT images, and a composite of the gated frames. This study examines the usefulness of extracting one or a combination of frames from the gated image to assess perfusion, and whether the addition of a temporal filter to the gated image improves signal to noise. Choice of the most appropriate frame was also considered. Sixteen and eight frame gated SPECT studies were simulated using the dynamic NURBS-based cardiac torso (NCAT) phantom. Variously sized perfusion defects were included in the inferior wall to assess contrast to normal tissue. Scatter and attenuation were not included. Butterworth spatial cutoff frequencies were varied to establish the most appropriate combination of temporal/spatial filters to reduce noise and retain contrast in the images. The 16 frame data produced higher ejection fraction across all spatial filter cutoffs, and generally was unaffected by temporal filtering. Temporal filtering reduced the noise in a uniform liver region in the gated images to within 25% of the composite image noise. The lesion extent and contrast were greater in the end-diastolic frames compared to end-systolic and mid-cycle frames. In conclusion, by using a temporally filtered end-diastolic image from the gated sequence, a favourable balance between noise and contrast can be achieved. Work is progress to confirm these findings in the clinical situation. Copyright (2002) The Australian and New Zealand Society of Nuclear Medicine Inc

  19. Noninvasive PET quantitative myocardial blood flow with regadenoson for assessing cardiac allograft vasculopathy in orthotopic heart transplantation patients.

    Science.gov (United States)

    Pampaloni, Miguel Hernandez; Shrestha, Uttam M; Sciammarella, Maria; Seo, Youngho; Gullberg, Grant T; Botvinick, Elias H

    2017-08-01

    Risk stratification and early detection of cardiac allograft vasculopathy (CAV) is essential in orthotopic heart transplantation (OHT) patients. This study assesses the changes in myocardial blood flow (MBF) noninvasively in OHT patients using quantitative cardiac PET with regadenoson. Twelve patients (Group 1) (8 males, 4 females, mean age 55 ± 7 years) with no history of post OHT myocardial ischemia were enrolled 5.4 ± 2.0 years after OHT. Fifteen patients (Group 2) (9 males, 6 females, mean age 71 ± 9 years) with intermediate pretest probability but not documented evidence for coronary artery disease (CAD) were also included to serve as control. Global and regional MBFs were assessed using dynamic 13 N-NH 3 PET at rest and during regadenoson-induced hyperemia. The coronary flow reserve (CFR) was also calculated as the ratio of hyperemic to resting MBF. Mean regadenoson-induced rate-pressure products were similar in both groups, while there was an increase in resting rate-pressure product in Group 1 patients. Both mean and median values of resting MBF were higher in Group 1 than Group 2 patients (1.33 ± 0.31 and 1.01 ± 0.21 mL/min/g for Groups 1 and 2, respectively, P < .001), while mean hyperemic MBF values were similar in both Groups (2.68 ± 0.84 and 2.64 ± 0.94 mL/min/g, P = NS) but median hyperemic MBF values were lower in Group 1 than Group 2 patients (2.0 vs. 2.60 mL/min/g, P = .018). Both mean and median CFR values demonstrated a significant reduction for Group 1 compared to Group 2 patients (2.07 ± 0.74 vs 2.63 ± 0.48, P = .025). This study suggests that the MBF in OHT patients may be abnormal at resting state with diminished CFR. This hints that the epicardial and microvascular coronary subsystem may be exacerbated after OHT leading to the gradual progression of CAV.

  20. A molecular switch driving inactivation in the cardiac K+ channel HERG.

    Directory of Open Access Journals (Sweden)

    David A Köpfer

    Full Text Available K(+ channels control transmembrane action potentials by gating open or closed in response to external stimuli. Inactivation gating, involving a conformational change at the K(+ selectivity filter, has recently been recognized as a major K(+ channel regulatory mechanism. In the K(+ channel hERG, inactivation controls the length of the human cardiac action potential. Mutations impairing hERG inactivation cause life-threatening cardiac arrhythmia, which also occur as undesired side effects of drugs. In this paper, we report atomistic molecular dynamics simulations, complemented by mutational and electrophysiological studies, which suggest that the selectivity filter adopts a collapsed conformation in the inactivated state of hERG. The selectivity filter is gated by an intricate hydrogen bond network around residues S620 and N629. Mutations of this hydrogen bond network are shown to cause inactivation deficiency in electrophysiological measurements. In addition, drug-related conformational changes around the central cavity and pore helix provide a functional mechanism for newly discovered hERG activators.

  1. Imaging of the myocardium using {sup 18}F-FDG-PET/MRI

    Energy Technology Data Exchange (ETDEWEB)

    Ferda, Jiří, E-mail: ferda@fnplzen.cz [Clinic of the Imaging Methods, University Hospital Plzen, Alej Svobody 80, 304 60 Plzeň (Czech Republic); Hromádka, Milan, E-mail: hromadkam@fnplzen.cz [Department of Cardiology, University Hospital Plzen, Alej Svobody 80, 304 60 Plzeň (Czech Republic); Baxa, Jan, E-mail: baxaj@fnplzen.cz [Clinic of the Imaging Methods, University Hospital Plzen, Alej Svobody 80, 304 60 Plzeň (Czech Republic)

    2016-10-15

    Highlights: • The natural combination of the metabolic and structural information is the most important strenghtof myocardial PET/MRI. • Metabolic conversion to glycolysis is needed in the assesment ov the viable myocardium. • Metabolic conversion to the fatty acid metabolism is the crucial in the assesment of the ischemic memory and myocardial inflammation. - Abstract: The introduction of the integrated hybrid PET/MRI equipment creates the possibility to perform PET and MRI simultaneously. Depending on the clinical question, the metabolic conversion to glycolytic activity or beta-oxidation is performed before the application of FDG. Since FDG aids to evaluate the energetic metabolism of the myocytes and myocardial MRI reaches the imaging capabilities of perfusion and tissue characterization in the daily routine, FDG-PET/MRI looks to be a promising method of PET/MRI exploitation in cardiac imaging. When myocardial FDG uptake should be evaluated in association with the perfusion distribution, the cross-evaluation of FDG accumulation distribution and perfusion distribution pattern is necessary. The different scenarios may be used in the assessment of myocardium, the conversion to glycolytic activity is used in the imaging of the viable myocardium, but the glycolytic activity suppression might be used in the indications of the identification of injured myocardium by ischemia or inflammation. FDG-PET/MRI might aid to answer the clinical tasks according to the structure, current function and possibilities to improve the function in ischemic heart disease or to display the extent or activity of myocardial inflammation in sarcoidosis. The tight coupling between metabolism, perfusion and contractile function offers an opportunity for the simultaneous assessment of cardiac performance using one imaging modality.

  2. Evaluation of PET Imaging Resolution Using 350 mu{m} Pixelated CZT as a VP-PET Insert Detector

    Science.gov (United States)

    Yin, Yongzhi; Chen, Ximeng; Li, Chongzheng; Wu, Heyu; Komarov, Sergey; Guo, Qingzhen; Krawczynski, Henric; Meng, Ling-Jian; Tai, Yuan-Chuan

    2014-02-01

    A cadmium-zinc-telluride (CZT) detector with 350 μm pitch pixels was studied in high-resolution positron emission tomography (PET) imaging applications. The PET imaging system was based on coincidence detection between a CZT detector and a lutetium oxyorthosilicate (LSO)-based Inveon PET detector in virtual-pinhole PET geometry. The LSO detector is a 20 ×20 array, with 1.6 mm pitches, and 10 mm thickness. The CZT detector uses ac 20 ×20 ×5 mm substrate, with 350 μm pitch pixelated anodes and a coplanar cathode. A NEMA NU4 Na-22 point source of 250 μm in diameter was imaged by this system. Experiments show that the image resolution of single-pixel photopeak events was 590 μm FWHM while the image resolution of double-pixel photopeak events was 640 μm FWHM. The inclusion of double-pixel full-energy events increased the sensitivity of the imaging system. To validate the imaging experiment, we conducted a Monte Carlo (MC) simulation for the same PET system in Geant4 Application for Emission Tomography. We defined LSO detectors as a scanner ring and 350 μm pixelated CZT detectors as an insert ring. GATE simulated coincidence data were sorted into an insert-scanner sinogram and reconstructed. The image resolution of MC-simulated data (which did not factor in positron range and acolinearity effect) was 460 μm at FWHM for single-pixel events. The image resolutions of experimental data, MC simulated data, and theoretical calculation are all close to 500 μm FWHM when the proposed 350 μm pixelated CZT detector is used as a PET insert. The interpolation algorithm for the charge sharing events was also investigated. The PET image that was reconstructed using the interpolation algorithm shows improved image resolution compared with the image resolution without interpolation algorithm.

  3. Comparison of 16-frame and 8-frame gated SPET imaging for determination of left ventricular volumes and ejection fraction

    International Nuclear Information System (INIS)

    Navare, Sachin M.; Liu, Yi-Hwa; Wackers, Frans J.T.

    2003-01-01

    Electrocardiographic (ECG) gated single-photon emission tomography (SPET) allows for simultaneous assessment of myocardial perfusion and left ventricular (LV) function. Presently 8-frame per cardiac cycle ECG gating of SPET images is standard. The aim of this study was to compare the effect of 8-frame and 16-frame gated SPET on measurements of LV volumes and to evaluate the effects of the presence of myocardial perfusion defects and of radiotracer dose administered on the calculation of LV volumes. A total of 86 patients underwent technetium-99m SPET myocardial perfusion imaging using 16-frame per cardiac cycle acquisition. Eight-frame gated SPET images were generated by summation of contiguous frames. Left ventricular end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (EF) were calculated from the 16-frame and 8-frame data sets. The patients were divided into groups according to the administered dose of the radiotracer and the size of the perfusion defect. Results. Sixteen frame per cardiac cycle acquisition resulted in significantly larger EDV (122±72 ml vs 115±68 ml, P<0.0001), smaller ESV (64±58.6 ml vs 67.6±59.5 ml, P<0.0001), and higher LVEF (55.3%±18% vs 49%±17.4%, P<0.0001) as compared to 8-frame SPET imaging. This effect was seen regardless of whether a high or a low dose was administered and whether or not significant perfusion defects were present. This study shows that EDV, ESV and LVEF determined by 16-frame gated SPET are significantly different from those determined by 8-frame gated SPET. The radiotracer dose and perfusion defects do not affect estimation of LV parameters by 16-frame gated SPET. (orig.)

  4. Functional assessment of the right ventricle with gated myocardial perfusion SPECT

    International Nuclear Information System (INIS)

    Wadhwa, S.S.; Abbati, D.; Carolan, M.

    2002-01-01

    Full text: Evaluation of right ventricular function can provide valuable information in a variety of cardiac and non-cardiac conditions. Functional assessment of the right ventricle is difficult owing to its anatomy and geometry. We describe a method of assessing right ventricular function using gated myocardial perfusion SPECT. In 20 patients right and left ventricular ejection fractions (RVEF, LVEF) were determined using gated blood pool (GBPS) and gated myocardial perfusion SPECT (GSPECT). To avoid contamination with right atrial activity the two frame method was adopted for gated blood pool data when measuring RVEF. In 9 patients with normal right ventricles, an index of wall thickening for the right ventricle was derived from the peak systolic and diastolic counts in the free wall. There was good linear correlation between the two methods adopted for calculation of LVEF and RVEF. Bland - Airman analysis demonstrated good agreement between the two methods with no specific bias. The mean LVEF was 47.9 +/-12% (GBPS) and 47.3 +/- 12.4 (GSPECT). The mean RVEF was 43.2 +/- 9.6% (GBPS) and 44.2 +/- 8.5% (GSPECT). In both cases the values were significantly different. The mean wall motion index was 35%. There was no correlation between the wall thickness index and ejection fraction however the index was greater in patients with normal right ventricle than in those with reduced RVER Gated SPECT offers an alternative to GBPS for the functional assessment of the right ventricle. Utilising GSPECT will allow the simultaneous assessment of both the right and left ventricles. Copyright (2002) The Australian and New Zealand Society of Nuclear Medicine Inc

  5. TH-E-202-03: PET for Tumor Response Evaluation

    International Nuclear Information System (INIS)

    Lu, W.

    2016-01-01

    PET/CT is a very important imaging tool in the management of oncology patients. PET/CT has been applied for treatment planning and response evaluation in radiation therapy. This educational session will discuss: Pitfalls and remedies in PET/CT imaging for RT planning The use of hypoxia PET imaging for radiotherapy PET for tumor response evaluation The first presentation will address the issue of mis-registration between the CT and PET images in the thorax and the abdomen. We will discuss the challenges of respiratory gating and introduce an average CT technique to improve the registration for dose calculation and image-guidance in radiation therapy. The second presentation will discuss the use of hypoxia PET Imaging for radiation therapy. We will discuss various hypoxia radiotracers, the choice of clinical acquisition protocol (in particular a single late static acquisition versus a dynamic acquisition), and the compartmental modeling with different transfer rate constants explained. We will demonstrate applications of hypoxia imaging for dose escalation/de-escalation in clinical trials. The last presentation will discuss the use of PET/CT for tumor response evaluation. We will discuss anatomic response assessment vs. metabolic response assessment, visual evaluation and semi-quantitative evaluation, and limitations of current PET/CT assessment. We will summarize clinical trials using PET response in guiding adaptive radiotherapy. Finally, we will summarize recent advancements in PET/CT radiomics and non-FDG PET tracers for response assessment. Learning Objectives: Identify the causes of mis-registration of CT and PET images in PET/CT, and review the strategies to remedy the issue. Understand the basics of PET imaging of tumor hypoxia (radiotracers, how PET measures the hypoxia selective uptake, imaging protocols, applications in chemo-radiation therapy). Understand the basics of dynamic PET imaging, compartmental modeling and parametric images. Understand the

  6. TH-E-202-03: PET for Tumor Response Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Lu, W. [University of Maryland School of Medicine (United States)

    2016-06-15

    PET/CT is a very important imaging tool in the management of oncology patients. PET/CT has been applied for treatment planning and response evaluation in radiation therapy. This educational session will discuss: Pitfalls and remedies in PET/CT imaging for RT planning The use of hypoxia PET imaging for radiotherapy PET for tumor response evaluation The first presentation will address the issue of mis-registration between the CT and PET images in the thorax and the abdomen. We will discuss the challenges of respiratory gating and introduce an average CT technique to improve the registration for dose calculation and image-guidance in radiation therapy. The second presentation will discuss the use of hypoxia PET Imaging for radiation therapy. We will discuss various hypoxia radiotracers, the choice of clinical acquisition protocol (in particular a single late static acquisition versus a dynamic acquisition), and the compartmental modeling with different transfer rate constants explained. We will demonstrate applications of hypoxia imaging for dose escalation/de-escalation in clinical trials. The last presentation will discuss the use of PET/CT for tumor response evaluation. We will discuss anatomic response assessment vs. metabolic response assessment, visual evaluation and semi-quantitative evaluation, and limitations of current PET/CT assessment. We will summarize clinical trials using PET response in guiding adaptive radiotherapy. Finally, we will summarize recent advancements in PET/CT radiomics and non-FDG PET tracers for response assessment. Learning Objectives: Identify the causes of mis-registration of CT and PET images in PET/CT, and review the strategies to remedy the issue. Understand the basics of PET imaging of tumor hypoxia (radiotracers, how PET measures the hypoxia selective uptake, imaging protocols, applications in chemo-radiation therapy). Understand the basics of dynamic PET imaging, compartmental modeling and parametric images. Understand the

  7. Clinical cardiac positron emission tomography: State of the art

    International Nuclear Information System (INIS)

    Gould, K.L.

    1991-01-01

    Cardiac positron emission tomography (PET) has evolved rapidly from a relatively esoteric research tool into clinical applications providing unique, quantitative information on myocardial perfusion, metabolism, and cell membrane function and having a potentially significant impact on cardiovascular medicine. Although there are many different positron radionuclides for imaging diverse myocardial behavior, three radionuclides have reached accepted clinical utility. Cardiac PET using nitrogen-13-ammonia, rubidium-82, and fluoro-18-deoxyglucose has proved accurate and definitive in multiple university and private-practice sites for diagnosing and assessing severity and location of coronary artery disease in symptomatic or asymptomatic patients, for identifying injured but viable myocardium potentially salvageable by revascularization, and for ruling out clinically significant coronary artery stenosis with a high specificity in patients who might otherwise undergo coronary arteriography to document the absence of significant disease. 89 references

  8. Diabetic db/db mice do not develop heart failure upon pressure overload: a longitudinal in vivo PET, MRI, and MRS study on cardiac metabolic, structural, and functional adaptations.

    Science.gov (United States)

    Abdurrachim, Desiree; Nabben, Miranda; Hoerr, Verena; Kuhlmann, Michael T; Bovenkamp, Philipp; Ciapaite, Jolita; Geraets, Ilvy M E; Coumans, Will; Luiken, Joost J F P; Glatz, Jan F C; Schäfers, Michael; Nicolay, Klaas; Faber, Cornelius; Hermann, Sven; Prompers, Jeanine J

    2017-08-01

    Heart failure is associated with altered myocardial substrate metabolism and impaired cardiac energetics. Comorbidities like diabetes may influence the metabolic adaptations during heart failure development. We quantified to what extent changes in substrate preference, lipid accumulation, and energy status predict the longitudinal development of hypertrophy and failure in the non-diabetic and the diabetic heart. Transverse aortic constriction (TAC) was performed in non-diabetic (db/+) and diabetic (db/db) mice to induce pressure overload. Magnetic resonance imaging, 31P magnetic resonance spectroscopy (MRS), 1H MRS, and 18F-fluorodeoxyglucose-positron emission tomography (PET) were applied to measure cardiac function, energy status, lipid content, and glucose uptake, respectively. In vivo measurements were complemented with ex vivo techniques of high-resolution respirometry, proteomics, and western blotting to elucidate the underlying molecular pathways. In non-diabetic mice, TAC induced progressive cardiac hypertrophy and dysfunction, which correlated with increased protein kinase D-1 (PKD1) phosphorylation and increased glucose uptake. These changes in glucose utilization preceded a reduction in cardiac energy status. At baseline, compared with non-diabetic mice, diabetic mice showed normal cardiac function, higher lipid content and mitochondrial capacity for fatty acid oxidation, and lower PKD1 phosphorylation, glucose uptake, and energetics. Interestingly, TAC affected cardiac function only mildly in diabetic mice, which was accompanied by normalization of phosphorylated PKD1, glucose uptake, and cardiac energy status. The cardiac metabolic adaptations in diabetic mice seem to prevent the heart from failing upon pressure overload, suggesting that restoring the balance between glucose and fatty acid utilization is beneficial for cardiac function. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions

  9. Quantification of myocardial blood flow with 11C-hydroxyephedrine dynamic PET: comparison with 15O-H2O PET.

    Science.gov (United States)

    Hiroshima, Yuji; Manabe, Osamu; Naya, Masanao; Tomiyama, Yuuki; Magota, Keiichi; Obara, Masahiko; Aikawa, Tadao; Oyama-Manabe, Noriko; Yoshinaga, Keiichiro; Hirata, Kenji; Kroenke, Markus; Tamaki, Nagara; Katoh, Chietsugu

    2017-12-21

    11 C-hydroxyephedrine (HED) PET has been used to evaluate the myocardial sympathetic nervous system (SNS). Here we sought to establish a simultaneous approach for quantifying both myocardial blood flow (MBF) and the SNS from a single HED PET scan. Ten controls and 13 patients with suspected cardiac disease were enrolled. The inflow rate of 11 C-HED (K1) was obtained using a one-tissue-compartment model. We compared this rate with the MBF derived from 15 O-H 2 O PET. In the controls, the relationship between K 1 from 11 C-HED PET and the MBF from 15 O-H 2 O PET was linked by the Renkin-Crone model. The relationship between K 1 from 11 C-HED PET and the MBF from 15 O-H 2 O PET from the controls' data was approximated as follows: K 1   =  (1 - 0.891 * exp(- 0.146/MBF)) * MBF. In the validation set, the correlation coefficient demonstrated a significantly high relationship for both the whole left ventricle (r = 0.95, P < 0.001) and three coronary territories (left anterior descending artery: r = 0.96, left circumflex artery: r = 0.81, right coronary artery: r =  0.86; P < 0.001, respectively). 11 C-HED can simultaneously estimate MBF and sympathetic nervous function without requiring an additional MBF scan for assessing mismatch areas between MBF and SNS.

  10. Low-dose myocardial blood flow imaging using 82Rb-PET (RUBILOW 2.0)

    DEFF Research Database (Denmark)

    Hoff, Camilla Molich; Tolbod, Lars Poulsen; Harms, Hans

    2017-01-01

    Aim: Relative and absolute measures of myocardial blood flow (MBF) can be derived from a 82Rb PET/CT scan using list mode data to extract static, gated and dynamic PET series. High doses of 82Rb are used to maximize image quality in especially static images. High doses require large eluate volumes......, may degrade scanner dead time performance at first pass and decreases generator lifetime. Lower doses will expand the availability of 82Rb PET/CT and lower doses to personnel and patients. The aim of the current study was to examine MBF with a low dose (LD) 82Rb protocol compared to the institution......’s standard (STD) protocol. Methods: Twenty-one patients referred to 82Rb PET were included in the study. Patients were examined during rest and stress with repeated LD (740 MBq) and STD dose (1110 MBq) Rb-PET during the same imaging session. Regional and global rest and stress MBF values, total perfusion...

  11. Investigation of realistic PET simulations incorporating tumor patient's specificity using anthropomorphic models: Creation of an oncology database

    International Nuclear Information System (INIS)

    Papadimitroulas, Panagiotis; Efthimiou, Nikos; Nikiforidis, George C.; Kagadis, George C.; Loudos, George; Le Maitre, Amandine; Hatt, Mathieu; Tixier, Florent; Visvikis, Dimitris

    2013-01-01

    Purpose: The GATE Monte Carlo simulation toolkit is used for the implementation of realistic PET simulations incorporating tumor heterogeneous activity distributions. The reconstructed patient images include noise from the acquisition process, imaging system's performance restrictions and have limited spatial resolution. For those reasons, the measured intensity cannot be simply introduced in GATE simulations, to reproduce clinical data. Investigation of the heterogeneity distribution within tumors applying partial volume correction (PVC) algorithms was assessed. The purpose of the present study was to create a simulated oncology database based on clinical data with realistic intratumor uptake heterogeneity properties.Methods: PET/CT data of seven oncology patients were used in order to create a realistic tumor database investigating the heterogeneity activity distribution of the simulated tumors. The anthropomorphic models (NURBS based cardiac torso and Zubal phantoms) were adapted to the CT data of each patient, and the activity distribution was extracted from the respective PET data. The patient-specific models were simulated with the Monte Carlo Geant4 application for tomography emission (GATE) in three different levels for each case: (a) using homogeneous activity within the tumor, (b) using heterogeneous activity distribution in every voxel within the tumor as it was extracted from the PET image, and (c) using heterogeneous activity distribution corresponding to the clinical image following PVC. The three different types of simulated data in each case were reconstructed with two iterations and filtered with a 3D Gaussian postfilter, in order to simulate the intratumor heterogeneous uptake. Heterogeneity in all generated images was quantified using textural feature derived parameters in 3D according to the ground truth of the simulation, and compared to clinical measurements. Finally, profiles were plotted in central slices of the tumors, across lines with

  12. An ASIC implementation of digital front-end electronics for a high resolution PET scanner

    International Nuclear Information System (INIS)

    Newport, D.F.; Young, J.W.

    1993-01-01

    AN Application Specific Integrated Circuit (ASIC) has been designed and fabricated which implements many of the current functions found in the digital front-end electronics for a high resolution Positron Emission Tomography (PET) scanner. The ASIC performs crystal selection, energy qualification, time correction, and event counting functions for block technology high resolution PET scanners. Digitized x and y position, event energy, and time information are used by the ASIC to determine block crystal number, qualify the event based on energy, and correct the event time. In addition, event counting and block dead time calculations are performed for system dead time corrections. A loadable sequencer for controlling the analog front-end electronics is also implemented. The ASIC is implemented in a 37,000 gate, 1.0 micron CMOS gate-array and is capable of handling 4 million events/second while reducing parts count, cost, and power consumption over current board-level designs

  13. Comparison of myocardial function between post-menopausal and pre-menopausal women: evaluation by gated myocardial SPECT

    International Nuclear Information System (INIS)

    Hwang, K. H.; Choa, Won Sick; Yoon, Min Ki

    2005-01-01

    In addition to inhibiting coronary atherosclerosis, estrogen is expected to have protective effects on cardiac myocytes. We investigated the difference in myocardial functional parameters evaluated by gated myocardial SPECT after adenosine-stress between post-menopausal and pre-menopausal healthy women. This study included 22 healthy post-menopausal women (mean age: 53.0 yr) and 20 pre-menopausal women (mean age: 43.0 yr) who performed Tc-99m tetrofosmin gated myocardial SPECT after adenosine-stress. Measured hemodynamic parameters, EDV, ESV, stroke volume, EF, cardiac output and cardiac index were compared between the two groups. For comparison, similar-aged two male groups with matched numbers were also studied. There was no significant difference in hemodynamic parameters. EDV, ESV, stroke volume, EF, or cardiac output between the post-menopausal and pre-menopausal women. However, post-menopausal women have a smaller cardiac index (mean: 1.95 L/min/m2 vs 2.20 L/min/m2; p=0.045) and adenosine-induced HR increase (mean : 80.5/min vs 89.7/min ; p=0.03), compared to the pre-menopausal women. On the contrary, the two male groups of the same age range and numbers with the women groups showed no significant difference in any myocardial parameters. These results suggest that menopause may be correlated with reduced increase in cardiac index and HR increase after adenosine-stress

  14. Comparison of myocardial function between post-menopausal and pre-menopausal women: evaluation by gated myocardial SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, K. H.; Choa, Won Sick; Yoon, Min Ki [Gachon Medical School, Gil Hospital, Incheon (Korea, Republic of)

    2005-07-01

    In addition to inhibiting coronary atherosclerosis, estrogen is expected to have protective effects on cardiac myocytes. We investigated the difference in myocardial functional parameters evaluated by gated myocardial SPECT after adenosine-stress between post-menopausal and pre-menopausal healthy women. This study included 22 healthy post-menopausal women (mean age: 53.0 yr) and 20 pre-menopausal women (mean age: 43.0 yr) who performed Tc-99m tetrofosmin gated myocardial SPECT after adenosine-stress. Measured hemodynamic parameters, EDV, ESV, stroke volume, EF, cardiac output and cardiac index were compared between the two groups. For comparison, similar-aged two male groups with matched numbers were also studied. There was no significant difference in hemodynamic parameters. EDV, ESV, stroke volume, EF, or cardiac output between the post-menopausal and pre-menopausal women. However, post-menopausal women have a smaller cardiac index (mean: 1.95 L/min/m2 vs 2.20 L/min/m2; p=0.045) and adenosine-induced HR increase (mean : 80.5/min vs 89.7/min ; p=0.03), compared to the pre-menopausal women. On the contrary, the two male groups of the same age range and numbers with the women groups showed no significant difference in any myocardial parameters. These results suggest that menopause may be correlated with reduced increase in cardiac index and HR increase after adenosine-stress.

  15. Quantitation of respiratory motion during 4D-PET/CT acquisition

    International Nuclear Information System (INIS)

    Nehmeh, S.A.; Erdi, Y.E.; Pan, T.; Yorke, E.; Mageras, G.S.; Rosenzweig, K.E.; Schoder, H.; Mostafavi, H.; Squire, O.; Pevsner, A.; Larson, S.M.; Humm, J.L.

    2004-01-01

    We report on the variability of the respiratory motion during 4D-PET/CT acquisition. The respiratory motion for five lung cancer patients was monitored by tracking external markers placed on the abdomen. CT data were acquired over an entire respiratory cycle at each couch position. The x-ray tube status was recorded by the tracking system, for retrospective sorting of the CT data as a function of respiration phase. Each respiratory cycle was sampled in ten equal bins. 4D-PET data were acquired in gated mode, where each breathing cycle was divided into ten 500 ms bins. For both CT and PET acquisition, patients received audio prompting to regularize breathing. The 4D-CT and 4D-PET data were then correlated according to their respiratory phases. The respiratory periods, and average amplitude within each phase bin, acquired in both modality sessions were then analyzed. The average respiratory motion period during 4D-CT was within 18% from that in the 4D-PET sessions. This would reflect up to 1.8% fluctuation in the duration of each 4D-CT bin. This small uncertainty enabled good correlation between CT and PET data, on a phase-to-phase basis. Comparison of the average-amplitude within the respiration trace, between 4D-CT and 4D- PET, on a bin-by-bin basis show a maximum deviation of ∼15%. This study has proved the feasibility of performing 4D-PET/CT acquisition. Respiratory motion was in most cases consistent between PET and CT sessions, thereby improving both the attenuation correction of PET images, and co-registration of PET and CT images. On the other hand, in two patients, there was an increased partial irregularity in their breathing motion, which would prevent accurately correlating the corresponding PET and CT images

  16. SU-E-J-123: Assessing Segmentation Accuracy of Internal Volumes and Sub-Volumes in 4D PET/CT of Lung Tumors Using a Novel 3D Printed Phantom

    International Nuclear Information System (INIS)

    Soultan, D; Murphy, J; James, C; Hoh, C; Moiseenko, V; Cervino, L; Gill, B

    2015-01-01

    Purpose: To assess the accuracy of internal target volume (ITV) segmentation of lung tumors for treatment planning of simultaneous integrated boost (SIB) radiotherapy as seen in 4D PET/CT images, using a novel 3D-printed phantom. Methods: The insert mimics high PET tracer uptake in the core and 50% uptake in the periphery, by using a porous design at the periphery. A lung phantom with the insert was placed on a programmable moving platform. Seven breathing waveforms of ideal and patient-specific respiratory motion patterns were fed to the platform, and 4D PET/CT scans were acquired of each of them. CT images were binned into 10 phases, and PET images were binned into 5 phases following the clinical protocol. Two scenarios were investigated for segmentation: a gate 30–70 window, and no gating. The radiation oncologist contoured the outer ITV of the porous insert with on CT images, while the internal void volume with 100% uptake was contoured on PET images for being indistinguishable from the outer volume in CT images. Segmented ITVs were compared to the expected volumes based on known target size and motion. Results: 3 ideal breathing patterns, 2 regular-breathing patient waveforms, and 2 irregular-breathing patient waveforms were used for this study. 18F-FDG was used as the PET tracer. The segmented ITVs from CT closely matched the expected motion for both no gating and gate 30–70 window, with disagreement of contoured ITV with respect to the expected volume not exceeding 13%. PET contours were seen to overestimate volumes in all the cases, up to more than 40%. Conclusion: 4DPET images of a novel 3D printed phantom designed to mimic different uptake values were obtained. 4DPET contours overestimated ITV volumes in all cases, while 4DCT contours matched expected ITV volume values. Investigation of the cause and effects of the discrepancies is undergoing

  17. Phase analysis in gated blood pool tomography

    International Nuclear Information System (INIS)

    Nakajima, Kenichi; Bunko, Hisashi; Tada, Akira; Taki, Junichi; Nanbu, Ichiro

    1984-01-01

    Phase analysis of gated blood pool study has been applied to detect the site of accessory conduction pathway (ACP) in the Wolff-Parkinson-White (WPW) syndrome; however, there was a limitation to detect the precise location of ACP by phase analysis alone. In this study, we applied phase analysis to gated blood pool tomography using seven pin hole tomography (7PT) and gated emission computed tomography (GECT) in 21 patients with WPW syndrome and 3 normal subjects. In 17 patients, the sites of ACPs were confirmed by epicardial mapping and the result of the surgical division of ACP. In 7PT, the site of ACP grossly agreed to the abnormal initial phase in phase image in 5 out of 6 patients with left cardiac type. In GECT, phase images were generated in short axial, vertical and horizontal long axial sections. In 8 out of 9 patients, the site of ACP was correctly identified by phase images, and in a patient who had two ACPs, initial phase corresponded to one of the two locations. Phase analysis of gated blood pool tomography has advantages for avoiding overlap of blood pools and for estimating three-dimensional propagation of the contraction, and can be a good adjunctive method in patients with WPW syndrome. (author)

  18. Prognostic value of gated 201Tl myocardial perfusion SPECT imaging in patients with coronary artery disease

    International Nuclear Information System (INIS)

    Li Zicheng; Chen Xiaoming; Xu Hao

    2006-01-01

    Objective: To study the prognostic value of gated 201 Tl myocardial perfusion SPECT imaging in patients with coronary artery disease and assessment of therapy strategy for the individual patient. Methods: Eighty-four patients underwent rest and exercise stress 201 Tl gated myocardial perfusion SPECT imaging and were followed up for (32.92 ± 16.77) months. Images were studied using 17 segments and 1 to 4 scoring. Global summed stress score (SSS), summed rest score (SRS) and summed difference score (SDS=SSS-SRS) were also calculated. Post-stress and rest ejection fraction (EF) were automatically measured. Results: Nine cardiac events occurred (3.90% per year). SSS, SDS, SRS and EF were the independent predictors of cardiac events (P 201 Tl myocardial perfusion SPECT imaging can provide prognostic assessment for the patients with coronary artery disease and guide in selection of therapeutic strategy. Among all of the indices SSS is the best predictors of cardiac events. (authors)

  19. Bicuspid aortic valves: Diagnostic accuracy of standard axial 64-slice chest CT compared to aortic valve image plane ECG-gated cardiac CT

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, David J., E-mail: david.murphy@st-vincents.ie [Department of Radiology, St Vincent' s University Hospital, Elm Park, Dublin 4 (Ireland); McEvoy, Sinead H., E-mail: s.mcevoy@st-vincents.ie [Department of Radiology, St Vincent' s University Hospital, Elm Park, Dublin 4 (Ireland); Iyengar, Sri, E-mail: sri.iyengar@nhs.net [Department of Radiology, Plymouth Hospitals NHS Trust, Plymouth Devon PL6 8DH (United Kingdom); Feuchtner, Gudrun, E-mail: Gudrun.Feuchtner@i-med.ac.at [Department of Radiology, Innsbruck Medical University, Anichstr. 35, A-6020 Innsbruck (Austria); Cury, Ricardo C., E-mail: r.cury@baptisthealth.net [Department of Radiology, Baptist Cardiac and Vascular Institute, 8900 North Kendall Drive, Miami, FL 33176 (United States); Roobottom, Carl, E-mail: carl.roobottom@nhs.net [Department of Radiology, Plymouth Hospitals NHS Trust, Plymouth Devon PL6 8DH (United Kingdom); Plymouth University Peninsula Schools of Medicine and Dentistry (United Kingdom); Baumueller, Stephan, E-mail: Hatem.Alkadhi@usz.ch [Institute for Diagnostic and Interventional Radiology, University Hospital Zurich, Raemistrasse 100, CH-8091 Zurich (Switzerland); Alkadhi, Hatem, E-mail: stephan.baumueller@usz.ch [Institute for Diagnostic and Interventional Radiology, University Hospital Zurich, Raemistrasse 100, CH-8091 Zurich (Switzerland); Dodd, Jonathan D., E-mail: jonniedodd@gmail.com [Department of Radiology, St Vincent' s University Hospital, Elm Park, Dublin 4 (Ireland)

    2014-08-15

    Objectives: To assess the diagnostic accuracy of standard axial 64-slice chest CT compared to aortic valve image plane ECG-gated cardiac CT for bicuspid aortic valves. Materials and methods: The standard axial chest CT scans of 20 patients with known bicuspid aortic valves were blindly, randomly analyzed for (i) the appearance of the valve cusps, (ii) the largest aortic sinus area, (iii) the longest aortic cusp length, (iv) the thickest aortic valve cusp and (v) valve calcification. A second blinded reader independently analyzed the appearance of the valve cusps. Forty-two age- and sex-matched patients with known tricuspid aortic valves were used as controls. Retrospectively ECG-gated cardiac CT multiphase reconstructions of the aortic valve were used as the gold-standard. Results: Fourteen (21%) scans were scored as unevaluable (7 bicuspid, 7 tricuspid). Of the remainder, there were 13 evaluable bicuspid valves, ten of which showed an aortic valve line sign, while the remaining three showed a normal Mercedes-Benz appearance owing to fused valve cusps. The 35 evaluable tricuspid aortic valves all showed a normal Mercedes-Benz appearance (P = 0.001). Kappa analysis = 0.62 indicating good interobserver agreement for the aortic valve cusp appearance. Aortic sinus areas, aortic cusp lengths and aortic cusp thicknesses of ≥3.8 cm{sup 2}, 3.2 cm and 1.6 mm respectively on standard axial chest CT best distinguished bicuspid from tricuspid aortic valves (P < 0.0001 for all). Of evaluable scans, the sensitivity, specificity, positive and negative predictive values of standard axial chest CT in diagnosing bicuspid aortic valves was 77% (CI 0.54–1.0), 100%, 100% and 70% respectively. Conclusion: The aortic valve is evaluable in approximately 80% of standard chest 64-slice CT scans. Bicuspid aortic valves may be diagnosed on evaluable scans with good diagnostic accuracy. An aortic valve line sign, enlarged aortic sinuses and elongated, thickened valve cusps are specific CT

  20. Performance of highly sensitive cardiac troponin T assay to detect ischaemia at PET-CT in low-risk patients with acute coronary syndrome: a prospective observational study.

    Science.gov (United States)

    Morawiec, Beata; Fournier, Stephane; Tapponnier, Maxime; Prior, John O; Monney, Pierre; Dunet, Vincent; Lauriers, Nathalie; Recordon, Frederique; Trana, Catalina; Iglesias, Juan-Fernando; Kawecki, Damian; Boulat, Olivier; Bardy, Daniel; Lamsidri, Sabine; Eeckhout, Eric; Hugli, Olivier; Muller, Olivier

    2017-07-10

    Highly sensitive troponin T (hs-TnT) assay has improved clinical decision-making for patients admitted with chest pain. However, this assay's performance in detecting myocardial ischaemia in a lowrisk population has been poorly documented. To assess hs-TnT assay's performance to detect myocardial ischaemia at positron emission tomography/CT (PET-CT) in low-risk patients admitted with chest pain. Patients admitted for chest pain with a nonconclusive ECG and negative standard cardiac troponin T results at admission and after 6 hours were prospectively enrolled. Their hs-TnT samples were at T0, T2 and T6. Physicians were blinded to hs-TnT results. All patients underwent a PET-CT at rest and during adenosine-induced stress. All patients with a positive PET-CT result underwent a coronary angiography. Forty-eight patients were included. Six had ischaemia at PET-CT. All of them had ≥1 significant stenosis at coronary angiography. Areas under the curve (95% CI) for predicting significant ischaemia at PET-CT using hs-TnT were 0.764 (0.515 to 1.000) at T0, 0.812(0.616 to 1.000) at T2 and 0.813(0.638 to 0.989) at T6. The receiver operating characteristicbased optimal cut-off value for hs-TnT at T0, T2 and T6 needed to exclude significant ischaemia at PET-CT was <4 ng/L. Using this value, sensitivity, specificity, positive and negative predictive values of hs-TnT to predict significant ischaemia were 83%/38%/16%/94% at T0, 100%/40%/19%/100% at T2 and 100%/43%/20%/100% at T6, respectively. Our findings suggest that in low-risk patients, using the hs-TnT assay with a cut-off value of 4 ng/L demonstrates excellent negative predictive value to exclude myocardial ischaemia detection at PET-CT, at the expense of weak specificity and positive predictive value. ClinicalTrials.gov Identifier: NCT01374607. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly

  1. Analysis and clinical usefullness of cardiac ECT images

    International Nuclear Information System (INIS)

    Hayashi, Makoto; Kagawa, Masaaki; Yamada, Yukinori

    1983-01-01

    We estimated basically and clinically myocardial ECT image and ECG gated cardiac blood-pool ECT image. ROC curve is used for the evaluation of the accuracy in diagnostic myocardial infarction. The accuracy in diagnostic of MI is superior in myocardial ECT image and ECT estimation is unnecessary skillfulness and experience. We can absene the whole defect of MI than planar image by using ECT. LVEDV between estimated volume and contrast volume is according to it and get one step for automatic analysis of cardiac volume. (author)

  2. Use of the GATE Monte Carlo package for dosimetry applications

    Energy Technology Data Exchange (ETDEWEB)

    Visvikis, D. [INSERM U650, LaTIM, University Hospital Medical School, F 29609 Brest (France)]. E-mail: Visvikis.Dimitris@univ-brest.fr; Bardies, M. [INSERM U601, CHU Nantes, F 44093 Nantes (France); Chiavassa, S. [INSERM U601, CHU Nantes, F 44093 Nantes (France); Danford, C. [Department of Medical Physics, MSKCC, New York (United States); Kirov, A. [Department of Medical Physics, MSKCC, New York (United States); Lamare, F. [INSERM U650, LaTIM, University Hospital Medical School, F 29609 Brest (France); Maigne, L. [Departement de Curietherapie-Radiotherapie, Centre Jean Perrin, F 63000 Clemont-Ferrand (France); Staelens, S. [UGent-ELIS, St-Pietersnieuwstraat, 41, B 9000 Gent (Belgium); Taschereau, R. [CRUMP Institute for Molecular Imaging, UCLA, Los Angeles (United States)

    2006-12-20

    One of the roles for Monte Carlo (MC) simulation studies is in the area of dosimetry. A number of different codes dedicated to dosimetry applications are available and widely used today, such as MCNP, EGSnrc and PTRAN. However, such codes do not easily facilitate the description of complicated 3D sources or emission tomography systems and associated data flow, which may be useful in different dosimetry application domains. Such problems can be overcome by the use of specific MC codes such as GATE (GEANT4 Application to Tomographic Emission), which is based on Geant4 libraries, providing a scripting interface with a number of advantages for the simulation of SPECT and PET systems. Despite this potential, its major disadvantage is in terms of efficiency involving long execution times for applications such as dosimetry. The strong points and disadvantages of GATE in comparison to other dosimetry specific codes are discussed and illustrated in terms of accuracy, efficiency and flexibility. A number of features, such as the use of voxelised and moving sources, as well as developments such as advanced visualization tools and the development of dose estimation maps allowing GATE to be used for dosimetry applications are presented. In addition, different examples from dosimetry applications with GATE are given. Finally, future directions with respect to the use of GATE for dosimetry applications are outlined.

  3. Application of machine learning methodology for pet-based definition of lung cancer

    Science.gov (United States)

    Kerhet, A.; Small, C.; Quon, H.; Riauka, T.; Schrader, L.; Greiner, R.; Yee, D.; McEwan, A.; Roa, W.

    2010-01-01

    We applied a learning methodology framework to assist in the threshold-based segmentation of non-small-cell lung cancer (nsclc) tumours in positron-emission tomography–computed tomography (pet–ct) imaging for use in radiotherapy planning. Gated and standard free-breathing studies of two patients were independently analysed (four studies in total). Each study had a pet–ct and a treatment-planning ct image. The reference gross tumour volume (gtv) was identified by two experienced radiation oncologists who also determined reference standardized uptake value (suv) thresholds that most closely approximated the gtv contour on each slice. A set of uptake distribution-related attributes was calculated for each pet slice. A machine learning algorithm was trained on a subset of the pet slices to cope with slice-to-slice variation in the optimal suv threshold: that is, to predict the most appropriate suv threshold from the calculated attributes for each slice. The algorithm’s performance was evaluated using the remainder of the pet slices. A high degree of geometric similarity was achieved between the areas outlined by the predicted and the reference suv thresholds (Jaccard index exceeding 0.82). No significant difference was found between the gated and the free-breathing results in the same patient. In this preliminary work, we demonstrated the potential applicability of a machine learning methodology as an auxiliary tool for radiation treatment planning in nsclc. PMID:20179802

  4. Motion-compensated PET image reconstruction with respiratory-matched attenuation correction using two low-dose inhale and exhale CT images

    International Nuclear Information System (INIS)

    Nam, Woo Hyun; Ahn, Il Jun; Ra, Jong Beom; Kim, Kyeong Min; Kim, Byung Il

    2013-01-01

    Positron emission tomography (PET) is widely used for diagnosis and follow up assessment of radiotherapy. However, thoracic and abdominal PET suffers from false staging and incorrect quantification of the radioactive uptake of lesion(s) due to respiratory motion. Furthermore, respiratory motion-induced mismatch between a computed tomography (CT) attenuation map and PET data often leads to significant artifacts in the reconstructed PET image. To solve these problems, we propose a unified framework for respiratory-matched attenuation correction and motion compensation of respiratory-gated PET. For the attenuation correction, the proposed algorithm manipulates a 4D CT image virtually generated from two low-dose inhale and exhale CT images, rather than a real 4D CT image which significantly increases the radiation burden on a patient. It also utilizes CT-driven motion fields for motion compensation. To realize the proposed algorithm, we propose an improved region-based approach for non-rigid registration between body CT images, and we suggest a selection scheme of 3D CT images that are respiratory-matched to each respiratory-gated sinogram. In this work, the proposed algorithm was evaluated qualitatively and quantitatively by using patient datasets including lung and/or liver lesion(s). Experimental results show that the method can provide much clearer organ boundaries and more accurate lesion information than existing algorithms by utilizing two low-dose CT images. (paper)

  5. New SPECT and PET Radiopharmaceuticals for Imaging Cardiovascular Disease

    Directory of Open Access Journals (Sweden)

    Oyebola O. Sogbein

    2014-01-01

    Full Text Available Nuclear cardiology has experienced exponential growth within the past four decades with converging capacity to diagnose and influence management of a variety of cardiovascular diseases. Single photon emission computed tomography (SPECT myocardial perfusion imaging (MPI with technetium-99m radiotracers or thallium-201 has dominated the field; however new hardware and software designs that optimize image quality with reduced radiation exposure are fuelling a resurgence of interest at the preclinical and clinical levels to expand beyond MPI. Other imaging modalities including positron emission tomography (PET and magnetic resonance imaging (MRI continue to emerge as powerful players with an expanded capacity to diagnose a variety of cardiac conditions. At the forefront of this resurgence is the development of novel target vectors based on an enhanced understanding of the underlying pathophysiological process in the subcellular domain. Molecular imaging with novel radiopharmaceuticals engineered to target a specific subcellular process has the capacity to improve diagnostic accuracy and deliver enhanced prognostic information to alter management. This paper, while not comprehensive, will review the recent advancements in radiotracer development for SPECT and PET MPI, autonomic dysfunction, apoptosis, atherosclerotic plaques, metabolism, and viability. The relevant radiochemistry and preclinical and clinical development in addition to molecular imaging with emerging modalities such as cardiac MRI and PET-MR will be discussed.

  6. Validation of use of the low energies library in the GATE program: assessment of the effective mass attenuation coefficient

    International Nuclear Information System (INIS)

    Argenta, J.; Brambilla, C.R.; Marques da Silva, A.M.; Hoff, G.

    2009-01-01

    GATE (Geant4 Application for Emission Tomography) is a versatile tool kit for nuclear medicine simulations of SPECT and PET studies. GATE takes advantage of well-validated libraries of physics processes models, geometry description, tracking of particles through materials, response of detector and visualization tools offered by Geant4. One package available to simulate electromagnetic interactions is LEP (Low Energy Electromagnetic Processes). The purpose of this work was to evaluate the LEP package used by GATE 4 for nuclear medicine shielding simulations. Several simulations were made involving a mono directional and 140 keV monoenergetic point source beam, passing through barriers of variable thickness of water and lead. The results showed good agreement with the theoretical model, indicating that GATE 4 uses correctly the LEP package. (author)

  7. The effect of respiratory induced density variations on non-TOF PET quantitation in the lung

    Science.gov (United States)

    Holman, Beverley F.; Cuplov, Vesna; Hutton, Brian F.; Groves, Ashley M.; Thielemans, Kris

    2016-04-01

    Accurate PET quantitation requires a matched attenuation map. Obtaining matched CT attenuation maps in the thorax is difficult due to the respiratory cycle which causes both motion and density changes. Unlike with motion, little attention has been given to the effects of density changes in the lung on PET quantitation. This work aims to explore the extent of the errors caused by pulmonary density attenuation map mismatch on dynamic and static parameter estimates. Dynamic XCAT phantoms were utilised using clinically relevant 18F-FDG and 18F-FMISO time activity curves for all organs within the thorax to estimate the expected parameter errors. The simulations were then validated with PET data from 5 patients suffering from idiopathic pulmonary fibrosis who underwent PET/Cine-CT. The PET data were reconstructed with three gates obtained from the Cine-CT and the average Cine-CT. The lung TACs clearly displayed differences between true and measured curves with error depending on global activity distribution at the time of measurement. The density errors from using a mismatched attenuation map were found to have a considerable impact on PET quantitative accuracy. Maximum errors due to density mismatch were found to be as high as 25% in the XCAT simulation. Differences in patient derived kinetic parameter estimates and static concentration between the extreme gates were found to be as high as 31% and 14%, respectively. Overall our results show that respiratory associated density errors in the attenuation map affect quantitation throughout the lung, not just regions near boundaries. The extent of this error is dependent on the activity distribution in the thorax and hence on the tracer and time of acquisition. Consequently there may be a significant impact on estimated kinetic parameters throughout the lung.

  8. The effect of respiratory induced density variations on non-TOF PET quantitation in the lung

    International Nuclear Information System (INIS)

    Holman, Beverley F; Cuplov, Vesna; Hutton, Brian F; Groves, Ashley M; Thielemans, Kris

    2016-01-01

    Accurate PET quantitation requires a matched attenuation map. Obtaining matched CT attenuation maps in the thorax is difficult due to the respiratory cycle which causes both motion and density changes. Unlike with motion, little attention has been given to the effects of density changes in the lung on PET quantitation. This work aims to explore the extent of the errors caused by pulmonary density attenuation map mismatch on dynamic and static parameter estimates. Dynamic XCAT phantoms were utilised using clinically relevant 18 F-FDG and 18 F-FMISO time activity curves for all organs within the thorax to estimate the expected parameter errors. The simulations were then validated with PET data from 5 patients suffering from idiopathic pulmonary fibrosis who underwent PET/Cine-CT. The PET data were reconstructed with three gates obtained from the Cine-CT and the average Cine-CT. The lung TACs clearly displayed differences between true and measured curves with error depending on global activity distribution at the time of measurement. The density errors from using a mismatched attenuation map were found to have a considerable impact on PET quantitative accuracy. Maximum errors due to density mismatch were found to be as high as 25% in the XCAT simulation. Differences in patient derived kinetic parameter estimates and static concentration between the extreme gates were found to be as high as 31% and 14%, respectively. Overall our results show that respiratory associated density errors in the attenuation map affect quantitation throughout the lung, not just regions near boundaries. The extent of this error is dependent on the activity distribution in the thorax and hence on the tracer and time of acquisition. Consequently there may be a significant impact on estimated kinetic parameters throughout the lung. (paper)

  9. A Comparison of Amplitude-Based and Phase-Based Positron Emission Tomography Gating Algorithms for Segmentation of Internal Target Volumes of Tumors Subject to Respiratory Motion

    International Nuclear Information System (INIS)

    Jani, Shyam S.; Robinson, Clifford G.; Dahlbom, Magnus; White, Benjamin M.; Thomas, David H.; Gaudio, Sergio; Low, Daniel A.; Lamb, James M.

    2013-01-01

    Purpose: To quantitatively compare the accuracy of tumor volume segmentation in amplitude-based and phase-based respiratory gating algorithms in respiratory-correlated positron emission tomography (PET). Methods and Materials: List-mode fluorodeoxyglucose-PET data was acquired for 10 patients with a total of 12 fluorodeoxyglucose-avid tumors and 9 lymph nodes. Additionally, a phantom experiment was performed in which 4 plastic butyrate spheres with inner diameters ranging from 1 to 4 cm were imaged as they underwent 1-dimensional motion based on 2 measured patient breathing trajectories. PET list-mode data were gated into 8 bins using 2 amplitude-based (equal amplitude bins [A1] and equal counts per bin [A2]) and 2 temporal phase-based gating algorithms. Gated images were segmented using a commercially available gradient-based technique and a fixed 40% threshold of maximum uptake. Internal target volumes (ITVs) were generated by taking the union of all 8 contours per gated image. Segmented phantom ITVs were compared with their respective ground-truth ITVs, defined as the volume subtended by the tumor model positions covering 99% of breathing amplitude. Superior-inferior distances between sphere centroids in the end-inhale and end-exhale phases were also calculated. Results: Tumor ITVs from amplitude-based methods were significantly larger than those from temporal-based techniques (P=.002). For lymph nodes, A2 resulted in ITVs that were significantly larger than either of the temporal-based techniques (P<.0323). A1 produced the largest and most accurate ITVs for spheres with diameters of ≥2 cm (P=.002). No significant difference was shown between algorithms in the 1-cm sphere data set. For phantom spheres, amplitude-based methods recovered an average of 9.5% more motion displacement than temporal-based methods under regular breathing conditions and an average of 45.7% more in the presence of baseline drift (P<.001). Conclusions: Target volumes in images generated

  10. Evaluating the pacemaker effect with the pump parameter of gated blood-pool imaging

    International Nuclear Information System (INIS)

    Cheng Muhua

    1995-01-01

    13 normal controls and 27 patients with ventricular pacemaker had undergone planar gated blood-pool imaging in different conditions. Result shows: (1) Pump parameters can successfully reflect therapeutic effect of pacemaker among them EMP is the most valuable parameter for evaluating the cardiac pumping effect. (2) After implantation of the ventricular pacemaker, the LVEF did not increase, but the CO and EMP was significantly increased. (3) Compared with right ventricular demand pacemaker, the rate-responsive ventricular pacemaker give better hemodynamic benefit at exercise condition. (4) Through restrained cardiac pacemaker the functional change was analyzed on or off pace, and monitoring the cardiac function itself after the pacemaker was implanted

  11. Measurement of cardiovascular function using a novel view-sharing PET reconstruction method and tracer kinetic analysis

    Directory of Open Access Journals (Sweden)

    Paul R. Territo

    2016-10-01

    Full Text Available Abstract Recent advancements in PET instrumentation have made the non-invasive assessment of cardiovascular function in small animals a reality. The majority of small animal PET systems use stationary detector gantries, thus affording high temporal resolution imaging of cardiac function. Systems designed to maximize spatial resolution and detection sensitivity employing rotating gantry designs are suboptimal when high temporal resolution imaging is needed. To overcome this limitation, the current work developed a novel view-sharing data analysis scheme suitable for dynamic cardiac PET imaging using 18F-NaF as the tracer and tracer kinetic model analysis. This scheme was tested in a rat model of cardiovascular function where the relationship between direct transonic flow measures of cardiac output were highly correlated (f(x = 1.0216x − 24.233, R = 0.9158, p < 0.001 with the new model. Similarly, derived measures of stroke volume were also highly correlated (f(x = 0.9655x − 0.0428, R = 0.9453, p < 0.001 with the current approach. Administration of xylazine caused a statistically significant increase in stroke volume (0.32 ± 0.07 ml, p = 0.003, n = 4 and a significant decrease in both heart rate (−155 ± 7.1 beats/min, p < 0.001, n = 4 and cardiac output (−75.9 ± 23.0 ml/kg min, p = 0.01, n = 4. These findings suggest that the new sinogram binning and kinetic modeling methods produce reliable cardiac function measures suitable for longitudinal monitoring of cardiovascular function.

  12. Investigation of realistic PET simulations incorporating tumor patient's specificity using anthropomorphic models: Creation of an oncology database

    Energy Technology Data Exchange (ETDEWEB)

    Papadimitroulas, Panagiotis; Efthimiou, Nikos; Nikiforidis, George C.; Kagadis, George C. [Department of Medical Physics, School of Medicine, University of Patras, Rion, GR 265 04 (Greece); Loudos, George [Department of Biomedical Engineering, Technological Educational Institute of Athens, Ag. Spyridonos Street, Egaleo GR 122 10, Athens (Greece); Le Maitre, Amandine; Hatt, Mathieu; Tixier, Florent; Visvikis, Dimitris [Medical Information Processing Laboratory (LaTIM), National Institute of Health and Medical Research (INSERM), 29609 Brest (France)

    2013-11-15

    Purpose: The GATE Monte Carlo simulation toolkit is used for the implementation of realistic PET simulations incorporating tumor heterogeneous activity distributions. The reconstructed patient images include noise from the acquisition process, imaging system's performance r