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Mandeville JB, Efthimiou N, Weigand-Whittier J, Hardy E, Knudsen GM, Jørgensen LM, Chen YCI. Partial volume correction of PET image data using geometric transfer matrices based on uniform B-splines. Phys Med Biol 2024; 69:055020. [PMID: 38271737 DOI: 10.1088/1361-6560/ad22a0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 01/25/2024] [Indexed: 01/27/2024]
Abstract
Objective. Most methods for partial volume correction (PVC) of positron emission tomography (PET) data employ anatomical segmentation of images into regions of interest. This approach is not optimal for exploratory functional imaging beyond regional hypotheses. Here, we describe a novel method for unbiased voxel-wise PVC.Approach.B-spline basis functions were combined with geometric transfer matrices to enable a method (bsGTM) that provides PVC or alternatively provides smoothing with minimal regional crosstalk. The efficacy of the proposed method was evaluated using Monte Carlo simulations, human PET data, and murine functional PET data.Main results.In simulations, bsGTM provided recovery of partial volume signal loss comparable to iterative deconvolution, while demonstrating superior resilience to noise. In a real murine PET dataset, bsGTM yielded much higher sensitivity for detecting amphetamine-induced reduction of [11C]raclopride binding potential. In human PET data, bsGTM smoothing enabled increased signal-to-noise ratios with less degradation of binding potentials relative to Gaussian convolution or non-local means.Significance.bsGTM offers improved performance for PVC relative to iterative deconvolution, the current method of choice for voxel-wise PVC, especially in the common PET regime of low signal-to-noise ratio. The new method provides an anatomically unbiased way to compensate partial volume errors in cases where anatomical segmentation is unavailable or of questionable relevance or accuracy.
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Affiliation(s)
- Joseph B Mandeville
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Boston MA, United States of America
- Harvard Medical School, Boston, MA, United States of America
| | - Nikos Efthimiou
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Boston MA, United States of America
- Harvard Medical School, Boston, MA, United States of America
| | - Jonah Weigand-Whittier
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Boston MA, United States of America
- Department of Bioengineering, University of California, Berkeley CA, United States of America
| | - Erin Hardy
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Boston MA, United States of America
| | - Gitte M Knudsen
- Neurobiology Research Unit, Rigshospitalet and University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Louise M Jørgensen
- Neurobiology Research Unit, Rigshospitalet and University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Yin-Ching I Chen
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Boston MA, United States of America
- Harvard Medical School, Boston, MA, United States of America
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2
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Xie H, Liu Z, Shi L, Greco K, Chen X, Zhou B, Feher A, Stendahl JC, Boutagy N, Kyriakides TC, Wang G, Sinusas AJ, Liu C. Segmentation-Free PVC for Cardiac SPECT Using a Densely-Connected Multi-Dimensional Dynamic Network. IEEE Trans Med Imaging 2023; 42:1325-1336. [PMID: 36459599 PMCID: PMC10204821 DOI: 10.1109/tmi.2022.3226604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
In nuclear imaging, limited resolution causes partial volume effects (PVEs) that affect image sharpness and quantitative accuracy. Partial volume correction (PVC) methods incorporating high-resolution anatomical information from CT or MRI have been demonstrated to be effective. However, such anatomical-guided methods typically require tedious image registration and segmentation steps. Accurately segmented organ templates are also hard to obtain, particularly in cardiac SPECT imaging, due to the lack of hybrid SPECT/CT scanners with high-end CT and associated motion artifacts. Slight mis-registration/mis-segmentation would result in severe degradation in image quality after PVC. In this work, we develop a deep-learning-based method for fast cardiac SPECT PVC without anatomical information and associated organ segmentation. The proposed network involves a densely-connected multi-dimensional dynamic mechanism, allowing the convolutional kernels to be adapted based on the input images, even after the network is fully trained. Intramyocardial blood volume (IMBV) is introduced as an additional clinical-relevant loss function for network optimization. The proposed network demonstrated promising performance on 28 canine studies acquired on a GE Discovery NM/CT 570c dedicated cardiac SPECT scanner with a 64-slice CT using Technetium-99m-labeled red blood cells. This work showed that the proposed network with densely-connected dynamic mechanism produced superior results compared with the same network without such mechanism. Results also showed that the proposed network without anatomical information could produce images with statistically comparable IMBV measurements to the images generated by anatomical-guided PVC methods, which could be helpful in clinical translation.
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3
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Petitclerc L, Hirschler L, Örzsik B, Asllani I, van Osch MJP. Arterial spin labeling signal in the CSF: Implications for partial volume correction and blood-CSF barrier characterization. NMR Biomed 2023; 36:e4852. [PMID: 36269104 PMCID: PMC10078195 DOI: 10.1002/nbm.4852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 09/21/2022] [Accepted: 10/13/2022] [Indexed: 06/16/2023]
Abstract
For better quantification of perfusion with arterial spin labeling (ASL), partial volume correction (PVC) is used to disentangle the signals from gray matter (GM) and white matter within any voxel. Based on physiological considerations, PVC algorithms typically assume zero signal in the cerebrospinal fluid (CSF). Recent measurements, however, have shown that CSF-ASL signal can exceed 10% of GM signal, even when using recommended ASL labeling parameters. CSF signal is expected to particularly affect PVC results in the choroid plexus. This study aims to measure the impact of CSF signal on PVC perfusion measurements, and to investigate the potential use of PVC to retrieve pure CSF-ASL signal for blood-CSF barrier characterization. In vivo imaging included six pCASL sequences with variable label duration and post-labeling delay (PLD), and an eight-echo 3D-GRASE readout. A dataset was simulated to estimate the effect of CSF-PVC with known ground-truth parameters. Differences between the results of CSF-PVC and non-CSF-PVC were estimated for regions of interest (ROIs) based on GM probability, and a separate ROI isolating the choroid plexus. In vivo, the suitability of PVC-CSF signal as an estimate of pure CSF was investigated by comparing its time course with the long-TE CSF signal. Results from both simulation and in vivo data indicated that including the CSF signal in PVC improves quantification of GM CBF by approximately 10%. In simulated data, this improvement was greater for multi-PLD (model fitting) quantification than for single PLD (~1-5% difference). In the choroid plexus, the difference between CSF-PVC and non-CSF-PVC was much larger, averaging around 30%. Long-TE (pure) CSF signal could not be estimated from PVC CSF signal as it followed a different time course, indicating the presence of residual macrovascular signal in the PVC. The inclusion of CSF adds value to PVC for more accurate measurements of GM perfusion, and especially for quantification of perfusion in the choroid plexus and study of the glymphatic system.
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Affiliation(s)
- Léonie Petitclerc
- C.J. Gorter MRI Center, Department of RadiologyLeiden University Medical CenterLeidenThe Netherlands
- Leiden Institute for Brain and Cognition (LIBC)LeidenThe Netherlands
- Department of RadiologyLeiden University Medical CenterLeidenThe Netherlands
| | - Lydiane Hirschler
- C.J. Gorter MRI Center, Department of RadiologyLeiden University Medical CenterLeidenThe Netherlands
- Department of RadiologyLeiden University Medical CenterLeidenThe Netherlands
| | - Balázs Örzsik
- Clinical Imaging Science Center, Department of NeuroscienceUniversity of SussexBrightonUK
| | - Iris Asllani
- Clinical Imaging Science Center, Department of NeuroscienceUniversity of SussexBrightonUK
- Department of Biomedical EngineeringRochester Institute of TechnologyRochesterNYUSA
| | - Matthias J. P. van Osch
- C.J. Gorter MRI Center, Department of RadiologyLeiden University Medical CenterLeidenThe Netherlands
- Leiden Institute for Brain and Cognition (LIBC)LeidenThe Netherlands
- Department of RadiologyLeiden University Medical CenterLeidenThe Netherlands
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4
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Mertens N, Michiels L, Vanderlinden G, Vandenbulcke M, Lemmens R, Van Laere K, Koole M. Impact of meningeal uptake and partial volume correction techniques on [ 18F]MK-6240 binding in aMCI patients and healthy controls. J Cereb Blood Flow Metab 2022; 42:1236-1246. [PMID: 35062837 PMCID: PMC9207493 DOI: 10.1177/0271678x221076023] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
[18F]MK-6240 is a second-generation tau PET-tracer to quantify neurofibrillary tangles in-vivo. However, individually variable levels of meningeal uptake induce spill-in-effects into the cortex, complicating [18F]MK-6240 PET quantification. Group SUVR differences between age-matched HC subgroups with varying extracerebral uptake (EC-low/mixed/high), and between aMCI and each HC subgroup were assessed without and with partial volume correction (PVC). Both Müller-Gartner (MG-)PVC and region-based voxelwise (RBV-)PVC, with the latter also correcting for extracerebral spill-in-effects, were implemented. Between HC groups, where no differences are to be expected, HC EC-high showed spill-in differences compared to HC EC-low when no PVC was applied while for MG-PVC, differences were reduced and, for RBV-PVC, no statistically significant differences were observed. Between aMCI and HC, cortical SUVR differences were statistically significant, both without and with PVC, but modulated by the varying meningeal uptake in HC subgroups when no PVC was applied. After applying PVC, correlations to clinical parameters improved and effect sizes between HC and aMCI increased, independent of the HC-subgroup. Therefore, appropriate PVC with correction for extracerebral spill-in-effects is recommended to minimize the impact of varying meningeal uptake on cortical differences between HC and aMCI.
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Affiliation(s)
- Nathalie Mertens
- Nuclear Medicine and Molecular Imaging, University Hospital and KU Leuven, Leuven, Belgium
| | - Laura Michiels
- Department of Neurosciences, Experimental Neurology, KU Leuven - University of Leuven, Leuven, Belgium.,VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium.,Department of Neurology, University Hospitals Leuven, Leuven, Belgium
| | - Greet Vanderlinden
- Nuclear Medicine and Molecular Imaging, University Hospital and KU Leuven, Leuven, Belgium
| | - Mathieu Vandenbulcke
- Department of Neurosciences, Experimental Neurology, KU Leuven - University of Leuven, Leuven, Belgium.,Old-Age Psychiatry, University Hospital and KU Leuven, Leuven, Belgium
| | - Robin Lemmens
- Department of Neurosciences, Experimental Neurology, KU Leuven - University of Leuven, Leuven, Belgium.,VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium.,Department of Neurology, University Hospitals Leuven, Leuven, Belgium
| | - Koen Van Laere
- Nuclear Medicine and Molecular Imaging, University Hospital and KU Leuven, Leuven, Belgium.,Division of Nuclear Medicine, University Hospitals Leuven, Belgium
| | - Michel Koole
- Nuclear Medicine and Molecular Imaging, University Hospital and KU Leuven, Leuven, Belgium
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5
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Driscoll B, Shek T, Vines D, Sun A, Jaffray D, Yeung I. Phantom Validation of a Conservation of Activity-Based Partial Volume Correction Method for Arterial Input Function in Dynamic PET Imaging. Tomography 2022; 8:842-857. [PMID: 35314646 PMCID: PMC8938778 DOI: 10.3390/tomography8020069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 03/10/2022] [Accepted: 03/16/2022] [Indexed: 11/16/2022] Open
Abstract
Dynamic PET (dPET) imaging can be utilized to perform kinetic modelling of various physiologic processes, which are exploited by the constantly expanding range of targeted radiopharmaceuticals. To date, dPET remains primarily in the research realm due to a number of technical challenges, not least of which is addressing partial volume effects (PVE) in the input function. We propose a series of equations for the correction of PVE in the input function and present the results of a validation study, based on a purpose built phantom. 18F-dPET experiments were performed using the phantom on a set of flow tubes representing large arteries, such as the aorta (1" 2.54 cm ID), down to smaller vessels, such as the iliac arteries and veins (1/4" 0.635 cm ID). When applied to the dPET experimental images, the PVE correction equations were able to successfully correct the image-derived input functions by as much as 59 ± 35% in the presence of background, which resulted in image-derived area under the curve (AUC) values within 8 ± 9% of ground truth AUC. The peak heights were similarly well corrected to within 9 ± 10% of the scaled DCE-CT curves. The same equations were then successfully applied to correct patient input functions in the aorta and internal iliac artery/vein. These straightforward algorithms can be applied to dPET images from any PET-CT scanner to restore the input function back to a more clinically representative value, without the need for high-end Time of Flight systems or Point Spread Function correction algorithms.
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Affiliation(s)
- Brandon Driscoll
- Quantitative Imaging for Personalized Cancer Medicine (QIPCM)—Techna Institute, University Health Network, Toronto, ON M5G 2C4, Canada; (T.S.); (D.J.); (I.Y.)
- Correspondence:
| | - Tina Shek
- Quantitative Imaging for Personalized Cancer Medicine (QIPCM)—Techna Institute, University Health Network, Toronto, ON M5G 2C4, Canada; (T.S.); (D.J.); (I.Y.)
| | - Douglass Vines
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON M5G 2M9, Canada; (D.V.); (A.S.)
- Department of Radiation Oncology, University of Toronto, Toronto, ON M5T 1P5, Canada
| | - Alex Sun
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON M5G 2M9, Canada; (D.V.); (A.S.)
- Department of Radiation Oncology, University of Toronto, Toronto, ON M5T 1P5, Canada
| | - David Jaffray
- Quantitative Imaging for Personalized Cancer Medicine (QIPCM)—Techna Institute, University Health Network, Toronto, ON M5G 2C4, Canada; (T.S.); (D.J.); (I.Y.)
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON M5G 2M9, Canada; (D.V.); (A.S.)
- Department of Radiation Oncology, University of Toronto, Toronto, ON M5T 1P5, Canada
| | - Ivan Yeung
- Quantitative Imaging for Personalized Cancer Medicine (QIPCM)—Techna Institute, University Health Network, Toronto, ON M5G 2C4, Canada; (T.S.); (D.J.); (I.Y.)
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON M5G 2M9, Canada; (D.V.); (A.S.)
- Department of Radiation Oncology, University of Toronto, Toronto, ON M5T 1P5, Canada
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6
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Poublanc J, Shafi R, Sobczyk O, Sam K, Mandell DM, Venkatraghavan L, Duffin J, Fisher JA, Mikulis DJ. Normal BOLD Response to a Step CO 2 Stimulus After Correction for Partial Volume Averaging. Front Physiol 2021; 12:639360. [PMID: 34194335 PMCID: PMC8236700 DOI: 10.3389/fphys.2021.639360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 04/26/2021] [Indexed: 11/26/2022] Open
Abstract
Cerebrovascular reactivity (CVR) is defined as the change in cerebral blood flow induced by a change in a vasoactive stimulus. CVR using BOLD MRI in combination with changes in end-tidal CO2 is a very useful method for assessing vascular performance. In recent years, this technique has benefited from an advanced gas delivery method where end-tidal CO2 can be targeted, measured very precisely, and validated against arterial blood gas sampling (Ito et al., 2008). This has enabled more precise comparison of an individual patient against a normative atlas of healthy subjects. However, expected control ranges for CVR metrics have not been reported in the literature. In this work, we calculate and report the range of control values for the magnitude (mCVR), the steady state amplitude (ssCVR), and the speed (TAU) of the BOLD response to a standard step stimulus, as well as the time delay (TD) as observed in a cohort of 45 healthy controls. These CVR metrics maps were corrected for partial volume averaging for brain tissue types using a linear regression method to enable more accurate quantitation of CVR metrics. In brief, this method uses adjacent voxel CVR metrics in combination with their tissue composition to write the corresponding set of linear equations for estimating CVR metrics of gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF). After partial volume correction, mCVR and ssCVR increase as expected in gray matter, respectively, by 25 and 19%, and decrease as expected in white matter by 33 and 13%. In contrast, TAU and TD decrease in gray matter by 33 and 13%. TAU increase in white matter by 24%, but TD surprisingly decreased by 9%. This correction enables more accurate voxel-wise tissue composition providing greater precision when reporting gray and white matter CVR values.
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Affiliation(s)
- Julien Poublanc
- Joint Department of Medical Imaging and the Functional Neuroimaging Laboratory, University Health Network, Toronto, ON, Canada
| | - Reema Shafi
- Joint Department of Medical Imaging and the Functional Neuroimaging Laboratory, University Health Network, Toronto, ON, Canada
| | - Olivia Sobczyk
- Joint Department of Medical Imaging and the Functional Neuroimaging Laboratory, University Health Network, Toronto, ON, Canada.,Department of Anesthesia and Pain Management, University Health Network, Toronto, ON, Canada
| | - Kevin Sam
- Department of Radiology and Radiological Sciences, Johns Hopkins University, United States
| | - Daniel M Mandell
- Joint Department of Medical Imaging and the Functional Neuroimaging Laboratory, University Health Network, Toronto, ON, Canada
| | | | - James Duffin
- Department of Anesthesia and Pain Management, University Health Network, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Joseph A Fisher
- Department of Anesthesia and Pain Management, University Health Network, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada.,Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - David J Mikulis
- Joint Department of Medical Imaging and the Functional Neuroimaging Laboratory, University Health Network, Toronto, ON, Canada.,Institute of Medical Science, University of Toronto, Toronto, ON, Canada
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7
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Nørgaard M, Ganz M, Svarer C, Frokjaer VG, Greve DN, Strother SC, Knudsen GM. Different preprocessing strategies lead to different conclusions: A [ 11C]DASB-PET reproducibility study. J Cereb Blood Flow Metab 2020; 40:1902-1911. [PMID: 31575336 PMCID: PMC7446563 DOI: 10.1177/0271678x19880450] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Positron emission tomography (PET) neuroimaging provides unique possibilities to study biological processes in vivo under basal and interventional conditions. For quantification of PET data, researchers commonly apply different arrays of sequential data analytic methods ("preprocessing pipeline"), but it is often unknown how the choice of preprocessing affects the final outcome. Here, we use an available data set from a double-blind, randomized, placebo-controlled [11C]DASB-PET study as a case to evaluate how the choice of preprocessing affects the outcome of the study. We tested the impact of 384 commonly used preprocessing strategies on a previously reported positive association between the change from baseline in neocortical serotonin transporter binding determined with [11C]DASB-PET, and change in depressive symptoms, following a pharmacological sex hormone manipulation intervention in 30 women. The two preprocessing steps that were most critical for the outcome were motion correction and kinetic modeling of the dynamic PET data. We found that 36% of the applied preprocessing strategies replicated the originally reported finding (p < 0.05). For preprocessing strategies with motion correction, the replication percentage was 72%, whereas it was 0% for strategies without motion correction. In conclusion, the choice of preprocessing strategy can have a major impact on a study outcome.
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Affiliation(s)
- Martin Nørgaard
- Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.,Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Melanie Ganz
- Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.,Department of Computer Science, University of Copenhagen, Copenhagen, Denmark
| | - Claus Svarer
- Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Vibe G Frokjaer
- Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Douglas N Greve
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Stephen C Strother
- Rotman Research Institute, Baycrest, Department of Medical Biophysics, University of Toronto, Toronto, Canada
| | - Gitte M Knudsen
- Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.,Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
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8
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Abstract
Partial volume effects (PVE) present a source of confound for the analysis of functional imaging data. Correction for PVE requires estimates of the partial volumes (PVs) present in an image. These estimates are conventionally obtained via volumetric segmentation, but such an approach may not be accurate for complex structures such as the cortex. An alternative is to use surface-based segmentation, which is well-established within the literature. Toblerone is a new method for estimating PVs using such surfaces. It uses a purely geometric approach that considers the intersection between a surface and the voxels of an image. In contrast to existing surface-based techniques, Toblerone is not restricted to use with any particular structure or modality. Evaluation in a neuroimaging context has been performed on simulated surfaces, simulated T1-weighted MRI images and finally a Human Connectome Project test-retest dataset. A comparison has been made to two existing surface-based methods; in all analyses Toblerone's performance either matched or surpassed the comparator methods. Evaluation results also show that compared to an existing volumetric method (FSL FAST), a surface-based approach with Toblerone offers improved robustness to scanner noise and field non-uniformity, and better inter-session repeatability in brain volume. In contrast to volumetric methods, a surface-based approach negates the need to perform resampling which is advantageous at the resolutions typically used for neuroimaging.
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9
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Lance Gould K, Bui L, Kitkungvan D, Pan T, Roby AE, Nguyen TT, Johnson NP. Pitfalls in quantitative myocardial PET perfusion I: Myocardial partial volume correction. J Nucl Cardiol 2020; 27:386-396. [PMID: 32095938 PMCID: PMC7174249 DOI: 10.1007/s12350-020-02073-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Accepted: 10/24/2019] [Indexed: 11/30/2022]
Abstract
BACKGROUND PET quantitative myocardial perfusion requires correction for partial volume loss due to one-dimensional LV wall thickness smaller than scanner resolution. METHODS We aimed to assess accuracy of risk stratification for death, MI, or revascularization after PET using partial volume corrections derived from two-dimensional ACR and three-dimensional NEMA phantoms for 3987 diagnostic rest-stress perfusion PETs and 187 MACE events. NEMA, ACR, and Tree phantoms were imaged with Rb-82 or F-18 for size-dependent partial volume loss. Perfusion and Coronary Flow Capacity were recalculated using different ACR- and NEMA-derived partial volume corrections compared by Kolmogorov-Smirnov statistics to standard perfusion metrics with established correlations with MACE. RESULTS Partial volume corrections based on two-dimensional ACR rods (two equal radii) and three-dimensional NEMA spheres (three equal radii) over estimate partial volume corrections, quantitative perfusion, and Coronary Flow Capacity by 50% to 150% over perfusion metrics with one-dimensional partial volume correction, thereby substantially impairing correct risk stratification. CONCLUSIONS ACR (2-dimensional) and NEMA (3-dimensional) phantoms overestimate partial volume corrections for 1-dimensional LV wall thickness and myocardial perfusion that are corrected with a simple equation that correlates with MACE for optimal risk stratification applicable to most PET-CT scanners for quantifying myocardial perfusion.
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Affiliation(s)
- K Lance Gould
- Martin Bucksbaum Distinguished University Chair, Weatherhead P.E.T. Center for Preventing and Reversing Atherosclerosis, McGovern Medical School, University of Texas Health Science Center, Houston, TX, USA.
- Weatherhead PET Center For Preventing and Reversing Atherosclerosis, McGovern Medical School, University of Texas Health Science Center at Houston, 6431 Fannin St., Room MSB 4.256, Houston, TX, 77030, USA.
- Weatherhead PET Center For Preventing and Reversing Atherosclerosis, Division of Cardiology, Department of Medicine, McGovern Medial Medical School, University of Texas, and Memorial Hermann Hospital, Houston, TX, USA.
| | - Linh Bui
- Division of Cardiology, McGovern Medical School, UT Health - Houston, Houston, TX, USA
- Weatherhead PET Center For Preventing and Reversing Atherosclerosis, Division of Cardiology, Department of Medicine, McGovern Medial Medical School, University of Texas, and Memorial Hermann Hospital, Houston, TX, USA
| | - Danai Kitkungvan
- Division of Cardiology, McGovern Medical School, UT Health - Houston, Houston, TX, USA
- Weatherhead PET Center For Preventing and Reversing Atherosclerosis, Division of Cardiology, Department of Medicine, McGovern Medial Medical School, University of Texas, and Memorial Hermann Hospital, Houston, TX, USA
| | - Tinsu Pan
- Imaging Physics Department, MD Anderson Cancer, University of Texas, Houston, TX, USA
- Weatherhead PET Center For Preventing and Reversing Atherosclerosis, Division of Cardiology, Department of Medicine, McGovern Medial Medical School, University of Texas, and Memorial Hermann Hospital, Houston, TX, USA
| | - Amanda E Roby
- Weatherhead PET Center, McGovern Medical School, Houston, TX, USA
- Weatherhead PET Center For Preventing and Reversing Atherosclerosis, Division of Cardiology, Department of Medicine, McGovern Medial Medical School, University of Texas, and Memorial Hermann Hospital, Houston, TX, USA
| | - Tung T Nguyen
- Programming and Data Management, Weatherhead P.E.T. Center, McGovern Medical School, University of Texas, Houston, TX, USA
- Weatherhead PET Center For Preventing and Reversing Atherosclerosis, Division of Cardiology, Department of Medicine, McGovern Medial Medical School, University of Texas, and Memorial Hermann Hospital, Houston, TX, USA
| | - Nils P Johnson
- Weatherhead Distinguished Chair of Heart Disease, Division of Cardiology, McGovern Medical School, Houston, TX, USA
- Weatherhead PET Center For Preventing and Reversing Atherosclerosis, Division of Cardiology, Department of Medicine, McGovern Medial Medical School, University of Texas, and Memorial Hermann Hospital, Houston, TX, USA
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10
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Turco A, Nuyts J, Duchenne J, Gheysens O, Voigt JU, Claus P, Vunckx K. Analysis of partial volume correction on quantification and regional heterogeneity in cardiac PET. J Nucl Cardiol 2020; 27:62-70. [PMID: 28233192 DOI: 10.1007/s12350-016-0773-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 11/27/2016] [Indexed: 11/29/2022]
Abstract
BACKGROUND The partial volume correction (PVC) of cardiac PET datasets using anatomical side information during reconstruction is appealing but not straightforward. Other techniques, which do not make use of additional anatomical information, could be equally effective in improving the reconstructed myocardial activity. METHODS Resolution modeling in combination with different noise suppressing priors was evaluated as a means to perform PVC. Anatomical priors based on a high-resolution CT are compared to non-anatomical, edge-preserving priors (relative difference and total variation prior). The study is conducted on ex vivo datasets from ovine hearts. A simulation study additionally clarifies the relationship between prior effectiveness and myocardial wall thickness. RESULTS Simple resolution modeling during data reconstruction resulted in over- and underestimation of activity, which hampers the absolute left ventricular quantification when compared to the ground truth. Both the edge-preserving and the anatomy-based PVC techniques improve the absolute quantification, with comparable results (Student t-test, P = .17). The relative tracer distribution was preserved with any reconstruction technique (repeated ANOVA, P = .98). CONCLUSIONS The use of edge-preserving priors emerged as optimal choice for quantification of tracer uptake in the left ventricular wall of the available datasets. Anatomical priors visually outperformed edge-preserving priors when the thinnest structures were of interest.
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Affiliation(s)
- A Turco
- Department of Imaging and Pathology, Nuclear Medicine and Molecular imaging, Medical Imaging Research Center (MIRC), KU Leuven - University of Leuven, B-3000, Leuven, Belgium.
| | - J Nuyts
- Department of Imaging and Pathology, Nuclear Medicine and Molecular imaging, Medical Imaging Research Center (MIRC), KU Leuven - University of Leuven, B-3000, Leuven, Belgium
| | - J Duchenne
- Department of Cardiovascular Sciences, Cardiology, Medical Imaging Research Center (MIRC), KU Leuven - University of Leuven, B-3000, Leuven, Belgium
| | - O Gheysens
- Department of Imaging and Pathology, Nuclear Medicine and Molecular imaging, Medical Imaging Research Center (MIRC), KU Leuven - University of Leuven, B-3000, Leuven, Belgium
- Department of Nuclear Medicine, University Hospitals Leuven, B-3000, Leuven, Belgium
| | - J U Voigt
- Department of Cardiovascular Sciences, Cardiology, Medical Imaging Research Center (MIRC), KU Leuven - University of Leuven, B-3000, Leuven, Belgium
- Department of Cardiovascular Diseases, University Hospitals Leuven, B-3000, Leuven, Belgium
| | - P Claus
- Department of Cardiovascular Sciences, Cardiology, Medical Imaging Research Center (MIRC), KU Leuven - University of Leuven, B-3000, Leuven, Belgium
| | - K Vunckx
- Department of Imaging and Pathology, Nuclear Medicine and Molecular imaging, Medical Imaging Research Center (MIRC), KU Leuven - University of Leuven, B-3000, Leuven, Belgium
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11
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Abstract
Positron emission tomography (PET) suffers from severe resolution limitations which reduce its quantitative accuracy. In this paper, we present a super-resolution (SR) imaging technique for PET based on convolutional neural networks (CNNs). To facilitate the resolution recovery process, we incorporate high-resolution (HR) anatomical information based on magnetic resonance (MR) imaging. We introduce the spatial location information of the input image patches as additional CNN inputs to accommodate the spatially-variant nature of the blur kernels in PET. We compared the performance of shallow (3-layer) and very deep (20-layer) CNNs with various combinations of the following inputs: low-resolution (LR) PET, radial locations, axial locations, and HR MR. To validate the CNN architectures, we performed both realistic simulation studies using the BrainWeb digital phantom and clinical studies using neuroimaging datasets. For both simulation and clinical studies, the LR PET images were based on the Siemens HR+ scanner. Two different scenarios were examined in simulation: one where the target HR image is the ground-truth phantom image and another where the target HR image is based on the Siemens HRRT scanner - a high-resolution dedicated brain PET scanner. The latter scenario was also examined using clinical neuroimaging datasets. A number of factors affected relative performance of the different CNN designs examined, including network depth, target image quality, and the resemblance between the target and anatomical images. In general, however, all deep CNNs outperformed classical penalized deconvolution and partial volume correction techniques by large margins both qualitatively (e.g., edge and contrast recovery) and quantitatively (as indicated by three metrics: peak signal-to-noise-ratio, structural similarity index, and contrast-to-noise ratio).
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Affiliation(s)
- Tzu-An Song
- Department of Electrical and Computer Engineering, University of Massachusetts Lowell, Lowell, MA, 01854 USA and co-affiliated with Massachusetts General Hospital, Boston, MA, 02114
| | - Samadrita Roy Chowdhury
- Department of Electrical and Computer Engineering, University of Massachusetts Lowell, Lowell, MA, 01854 USA and co-affiliated with Massachusetts General Hospital, Boston, MA, 02114
| | - Fan Yang
- Department of Electrical and Computer Engineering, University of Massachusetts Lowell, Lowell, MA, 01854 USA and co-affiliated with Massachusetts General Hospital, Boston, MA, 02114
| | - Joyita Dutta
- Department of Electrical and Computer Engineering, University of Massachusetts Lowell, Lowell, MA, 01854 USA and co-affiliated with Massachusetts General Hospital, Boston, MA, 02114
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12
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Song TA, Yang F, Chowdhury SR, Kim K, Johnson KA, El Fakhri G, Li Q, Dutta J. PET Image Deblurring and Super-Resolution with an MR-Based Joint Entropy Prior. IEEE Trans Comput Imaging 2019; 5:530-539. [PMID: 31723575 PMCID: PMC6853071 DOI: 10.1109/tci.2019.2913287] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The intrinsically limited spatial resolution of PET confounds image quantitation. This paper presents an image deblurring and super-resolution framework for PET using anatomical guidance provided by high-resolution MR images. The framework relies on image-domain post-processing of already-reconstructed PET images by means of spatially-variant deconvolution stabilized by an MR-based joint entropy penalty function. The method is validated through simulation studies based on the BrainWeb digital phantom, experimental studies based on the Hoffman phantom, and clinical neuroimaging studies pertaining to aging and Alzheimer's disease. The developed technique was compared with direct deconvolution and deconvolution stabilized by a quadratic difference penalty, a total variation penalty, and a Bowsher penalty. The BrainWeb simulation study showed improved image quality and quantitative accuracy measured by contrast-to-noise ratio, structural similarity index, root-mean-square error, and peak signal-to-noise ratio generated by this technique. The Hoffman phantom study indicated noticeable improvement in the structural similarity index (relative to the MR image) and gray-to-white contrast-to-noise ratio. Finally, clinical amyloid and tau imaging studies for Alzheimer's disease showed lowering of the coefficient of variation in several key brain regions associated with two target pathologies.
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Affiliation(s)
- Tzu-An Song
- Department of Electrical and Computer Engineering, University of Massachusetts Lowell, Lowell, MA, 01854, USA; Massachusetts General Hospital, Boston, MA, 02114, USA
| | - Fan Yang
- Department of Electrical and Computer Engineering, University of Massachusetts Lowell, Lowell, MA, 01854, USA; Massachusetts General Hospital, Boston, MA, 02114, USA
| | - Samadrita Roy Chowdhury
- Department of Electrical and Computer Engineering, University of Massachusetts Lowell, Lowell, MA, 01854, USA; Massachusetts General Hospital, Boston, MA, 02114, USA
| | - Kyungsang Kim
- Massachusetts General Hospital, Boston, MA, 02114, USA
| | | | | | - Quanzheng Li
- Massachusetts General Hospital, Boston, MA, 02114, USA
| | - Joyita Dutta
- Department of Electrical and Computer Engineering, University of Massachusetts Lowell, Lowell, MA, 01854, USA; Massachusetts General Hospital, Boston, MA, 02114, USA
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13
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Liu M, Paranjpe MD, Zhou X, Duy PQ, Goyal MS, Benzinger TL, Lu J, Wang R, Zhou Y. Sex modulates the ApoE ε4 effect on brain tau deposition measured by 18F-AV-1451 PET in individuals with mild cognitive impairment. Theranostics 2019; 9:4959-4970. [PMID: 31410194 PMCID: PMC6691387 DOI: 10.7150/thno.35366] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Accepted: 05/20/2019] [Indexed: 01/25/2023] Open
Abstract
The strongest genetic risk factor for Alzheimer's disease (AD) is the Apolipoprotein E type 4 allele (ApoE ε4). The interaction between sex and ApoE ε4 carrier status on AD risk remains an area of intense investigation. We hypothesized that sex modulates the relationship between ApoE ε4 carrier status and brain tau deposition (a quantitative endophenotype in AD) in individuals with mild cognitive impairment (MCI). Methods: Preprocessed 18F-AV-1451 tau and 18F-AV-45 amyloid PET images, T1-weighted structural magnetic resonance imaging (MRI) scans, demographic information, and cerebrospinal fluid (CSF) total tau (t-tau) and phosphorylated tau (p-tau) measurements from 108 MCI subjects in the Alzheimer's Disease Neuroimaging Initiative (ADNI) database were included. After downloading pre-processed images from ADNI, an iterative reblurred Van Cittertiteration partial volume correction (PVC) method was applied to all PET images. MRIs were used for PET spatial normalization. Regions of interest (ROIs) were defined in standard space, and standardized uptake value ratio (SUVR) images relative to cerebellum were computed. ApoE ε4 by sex interaction analyses on 18F-AV-1451 and CSF tau (t-tau, p-tau) were assessed using generalized linear models. The association between 18F-AV-1451 SUVR and CSF tau (t-tau, p-tau) was assessed. Results: After applying PVC and controlling for age, education level and global cortical 18F-AV-45 SUVR, we found that the entorhinal cortex, amygdala, parahippocampal gyrus, posterior cingulate, and occipital ROIs exhibited a significant ApoE ε4 by sex interaction effect (false discovery rate P < 0.1) among MCI individuals. We also found a significant ApoE ε4 by sex interaction effect on CSF t-tau and p-tau. 18F-AV-1451 SUVR in the 5 ROIs with ApoE ε4 by sex interaction was significantly correlated with CSF p-tau and t-tau. Conclusions: Our findings suggest that women are more susceptible to ApoE ε4-associated accumulation of neurofibrillary tangles in MCI compared to males. Both CSF tau (p-tau, t-tau) and brain tau PET are robust quantitative biomarkers for studying ApoE ε4 by sex effects on brain tau deposition in MCI participants.
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14
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Msayib Y, Harston GWJ, Sheerin F, Blockley NP, Okell TW, Jezzard P, Kennedy J, Chappell MA. Partial volume correction for quantitative CEST imaging of acute ischemic stroke. Magn Reson Med 2019; 82:1920-1928. [PMID: 31199009 PMCID: PMC6771886 DOI: 10.1002/mrm.27872] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Revised: 05/22/2019] [Accepted: 05/28/2019] [Indexed: 11/12/2022]
Abstract
Purpose Contributions of cerebrospinal fluid (CSF) have not been previously taken into account in the quantification of APT CEST effects, and correction for the dilution of CEST effects by CSF may allow for more robust measurement of CEST signals. The objective of this study was to compare the robustness of a partial volume (PV) correction model against a standard (4‐pool) multi‐pool model as far as their ability to quantify CEST effects in healthy, normal, and pathological tissue. Methods MRI data from 12 patients presenting with ischemic stroke, and 6 healthy subjects, were retrospectively analyzed. CEST signals derived from a 4‐pool model and a PV correction model were compared for repeatability and pathological tissue contrast. The effect of PV correction (PVC) was assessed within 3 ranges of tissue PV estimate (PVE): high PVE voxels, low PVE voxels, and the whole slice. Results In voxels with a high tissue PVE, PV correction did not make a significant difference to absolute APTR*. In low PVE voxels, the PVC model exhibited a significantly decreased ischemic core signal. The PVC measures exhibited higher repeatability between healthy subjects (4 pools: 3.4%, PVC: 2.4%) while maintaining a similar ischemic core CNR (0.7) to the 4‐pool model. In whole slice analysis it was found that both models exhibited similar results. Conclusions PV correction yielded a measure of APT effects that was more repeatable than standard 4‐pool analysis while achieving a similar CNR in pathological tissue, suggesting that PV‐corrected analysis was more robust at low values of tissue PVE.
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Affiliation(s)
- Y Msayib
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, United Kingdom
| | - G W J Harston
- Acute Vascular Imaging Centre, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - F Sheerin
- Acute Vascular Imaging Centre, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - N P Blockley
- Wellcome Centre for Integrative Neuroimaging, FMRIB Division, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - T W Okell
- Wellcome Centre for Integrative Neuroimaging, FMRIB Division, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - P Jezzard
- Wellcome Centre for Integrative Neuroimaging, FMRIB Division, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - J Kennedy
- Acute Vascular Imaging Centre, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - M A Chappell
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, United Kingdom.,Wellcome Centre for Integrative Neuroimaging, FMRIB Division, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
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15
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Smith CT, Crawford JL, Dang LC, Seaman KL, San Juan MD, Vijay A, Katz DT, Matuskey D, Cowan RL, Morris ED, Zald DH, Samanez-Larkin GR. Partial-volume correction increases estimated dopamine D2-like receptor binding potential and reduces adult age differences. J Cereb Blood Flow Metab 2019; 39:822-833. [PMID: 29090626 PMCID: PMC6498753 DOI: 10.1177/0271678x17737693] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The relatively modest spatial resolution of positron emission tomography (PET) increases the likelihood of partial volume effects such that binding potential (BPND) may be underestimated. Given structural grey matter losses across adulthood, partial volume effects may be even more problematic in older age leading to overestimation of adult age differences. Here we examined the effects of partial volume correction (PVC) in two studies from different sites using different high-affinity D2-like radioligands (18 F-Fallypride, 11C-FLB457) and different PET camera resolutions (∼5 mm, 2.5 mm). Results across both data sets revealed that PVC increased estimated BPND and reduced, though did not eliminate, age effects on BPND. As expected, the effects of PVC were smaller in higher compared to lower resolution data. Analyses using uncorrected data that controlled for grey matter volume in each region of interest approximated PVC corrected data for some but not all regions. Overall, the findings suggest that PVC increases estimated BPND in general and reduces adult age differences especially when using lower resolution cameras. The findings suggest that the past 30 years of research on dopamine receptor availability, for which very few studies use PVC, may overestimate effects of aging on dopamine receptor availability.
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Affiliation(s)
| | - Jennifer L Crawford
- 2 Department of Psychology, Yale University, New Haven, CT, USA.,3 Center for Cognitive Neuroscience, Duke University, Durham, NC, USA
| | - Linh C Dang
- 1 Department of Psychology, Vanderbilt University, Nashville, TN, USA
| | - Kendra L Seaman
- 2 Department of Psychology, Yale University, New Haven, CT, USA.,3 Center for Cognitive Neuroscience, Duke University, Durham, NC, USA
| | - M Danica San Juan
- 1 Department of Psychology, Vanderbilt University, Nashville, TN, USA
| | - Aishwarya Vijay
- 4 Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
| | - Daniel T Katz
- 1 Department of Psychology, Vanderbilt University, Nashville, TN, USA
| | - David Matuskey
- 4 Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA.,5 Department of Psychiatry, Yale University, New Haven, CT, USA
| | - Ronald L Cowan
- 1 Department of Psychology, Vanderbilt University, Nashville, TN, USA.,6 Department of Psychiatry and Behavioral Sciences, Vanderbilt University School of Medicine, Nashville, TN, USA.,7 Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Evan D Morris
- 4 Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA.,5 Department of Psychiatry, Yale University, New Haven, CT, USA.,8 Department of Biomedical Engineering, Yale University, New Haven, CT USA
| | - David H Zald
- 1 Department of Psychology, Vanderbilt University, Nashville, TN, USA.,6 Department of Psychiatry and Behavioral Sciences, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Gregory R Samanez-Larkin
- 2 Department of Psychology, Yale University, New Haven, CT, USA.,3 Center for Cognitive Neuroscience, Duke University, Durham, NC, USA.,9 Department of Psychology and Neuroscience, Duke University, Durham, NC, USA
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16
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Taghvaei R, Zadeh MZ, Sirous R, Shamchi SP, Raynor WY, Seraj SM, Moghbel M, Wang S, Werner TJ, Zhuang H, Alavi A. Pre-treatment partial-volume-corrected TLG is the best predictor of overall survival in patients with relapsing/refractory non-hodgkin lymphoma following radioimmunotherapy. Am J Nucl Med Mol Imaging 2018; 8:407-414. [PMID: 30697460 PMCID: PMC6334213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 11/19/2018] [Indexed: 06/09/2023]
Abstract
The role of fluorodeoxyglucose-positron emission tomography (FDG-PET) has been well established in assessment of lymphoma, including non-Hodgkin lymphoma (NHL). The aim of this study was to compare changes and survival predictive values of various quantification parameters of FDG-PET/CT in patients with relapsing/refractory lymphoma before and after radioimmunotherapy (RIT). Data from 17 patients with relapsing/refractory NHL, treated with targeted RIT after chemotherapy/radiotherapy, were retrospectively collected. FDG-PET/CT scans were performed approximately three months before and six months after RIT. An adaptive contrast-oriented thresholding algorithm was used to segment lesions on the FDG-PET images. Wilcoxon signed-rank tests were used to assess changes in SUVmax, SUVmean, partial volume-corrected SUVmean (pvcSUVmean), total lesion glycolysis (TLG), and pvcTLG before and after treatment. The patients were followed up after completing RIT for up to 10 years. Kaplan-Meier and Cox regression analyses evaluated the association between the quantification parameters and survival data. In the survived group, the decrease in mean percentage of change for TLG and pvcTLG was greater than SUVmax, SUVmean and pvcSUVmean [TLG: 253.9 to 106.9, -81.4%; P = 0.052 and pvcTLG: 368.9 to 153.3, -58.4%; P = 0.04]. In addition, overall survival (OS) was shorter in patients with pre-RIT pvcTLG more than 644 compared to those below this value (log-rank P < 0.01). In univariate Cox regression for OS, a higher baseline pvcTLG was a significant prognostic factor (HR: 6.8, P = 0.02). Our results showed that pre-treatment pvcTLG was the best predictor of OS in patients with relapsing/refractory NHL following RIT.
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Affiliation(s)
- Raheleh Taghvaei
- Department of Radiology, Hospital of The University of PennsylvaniaPA, USA
| | - Mahdi Zirakchian Zadeh
- Department of Radiology, Hospital of The University of PennsylvaniaPA, USA
- Department of Radiology, Children’s Hospital of PhiladelphiaPA, USA
| | - Reza Sirous
- University of Maryland Medical CenterBaltimore, MD, USA
| | | | - William Y Raynor
- Department of Radiology, Hospital of The University of PennsylvaniaPA, USA
- Drexel University College of MedicinePhiladelphia, PA, USA
| | | | - Mateen Moghbel
- Department of Radiology, Stanford University Medical CenterStanford, CA, USA
| | - Shiyu Wang
- Department of Dermatology, Hospital of The University of PennsylvaniaPA, USA
| | - Thomas J Werner
- Department of Radiology, Hospital of The University of PennsylvaniaPA, USA
| | - Hongming Zhuang
- Department of Radiology, Children’s Hospital of PhiladelphiaPA, USA
| | - Abass Alavi
- Department of Radiology, Hospital of The University of PennsylvaniaPA, USA
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17
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Mohy-Ud-Din H, Boutagy NE, Stendahl JC, Zhuang ZW, Sinusas AJ, Liu C. Quantification of intramyocardial blood volume with 99mTc-RBC SPECT-CT imaging: A preclinical study. J Nucl Cardiol 2018; 25:2096-2111. [PMID: 28695406 PMCID: PMC5985225 DOI: 10.1007/s12350-017-0970-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 06/13/2017] [Indexed: 10/19/2022]
Abstract
BACKGROUND Currently, there is no established non-invasive imaging approach to directly evaluate myocardial microcirculatory function in order to diagnose microvascular disease independent of co-existing epicardial disease. In this work, we developed a methodological framework for quantification of intramyocardial blood volume (IMBV) as a novel index of microcirculatory function with SPECT/CT imaging of 99mTc-labeled red blood cells (RBCs). METHODS Dual-gated myocardial SPECT/CT equilibrium imaging of 99mTc-RBCs was performed on twelve canines under resting conditions. Five correction schemes were studied: cardiac gating with no other corrections (CG), CG with attenuation correction (CG + AC), CG + AC with scatter correction (CG + AC + SC), dual cardiorespiratory gating with AC + SC (DG + AC + SC), and DG + AC + SC with partial volume correction (DG + AC + SC + PVC). Quantification of IMBV using each approach was evaluated in comparison to those obtained from all corrections. The in vivo SPECT estimates of IMBV values were validated against those obtained from ex vivo microCT imaging of the casted hearts. RESULTS The estimated IMBV with all corrections was 0.15 ± 0.03 for the end-diastolic phase and 0.11 ± 0.03 for the end-systolic phase. The cycle-dependent change in IMBV (ΔIMBV) with all corrections was 23.9 ± 8.6%. Schemes that applied no correction or partial correction resulted in significant over-estimation of IMBV and significant under-underestimation of ΔIMBV. Estimates of IMBV and ΔIMBV using all corrections were consistent with values reported in the literature using invasive techniques. In vivo SPECT estimates of IMBV strongly correlated (R2 ≥ 0.70) with ex vivo measures for the various correction schemes, while the fully corrected scheme yielded the smallest bias. CONCLUSIONS Non-invasive quantification of IMBV is feasible using 99mTc-RBCs SPECT/CT imaging, however, requires full compensation of physical degradation factors.
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Affiliation(s)
- Hassan Mohy-Ud-Din
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA.
- Shaukat Khanum Memorial Cancer Hospital and Research Center, 7-A, Block R-3, Johar Town, Lahore, 54000, Pakistan.
| | - Nabil E Boutagy
- Section of Cardiovascular Medicine, Department of Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - John C Stendahl
- Section of Cardiovascular Medicine, Department of Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Zhen W Zhuang
- Section of Cardiovascular Medicine, Department of Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Albert J Sinusas
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
- Section of Cardiovascular Medicine, Department of Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Chi Liu
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA.
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18
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Cal-Gonzalez J, Li X, Heber D, Rausch I, Moore SC, Schäfers K, Hacker M, Beyer T. Partial volume correction for improved PET quantification in 18F-NaF imaging of atherosclerotic plaques. J Nucl Cardiol 2018; 25:1742-1756. [PMID: 28176255 PMCID: PMC6153866 DOI: 10.1007/s12350-017-0778-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 12/16/2016] [Indexed: 11/15/2022]
Abstract
BACKGROUND Accurate quantification of plaque imaging using 18F-NaF PET requires partial volume correction (PVC). METHODS PVC of PET data was implemented by the use of a local projection (LP) method. LP-based PVC was evaluated with an image quality (NEMA) and with a thorax phantom with "plaque-type" lesions of 18-36 mL. The validated PVC method was then applied to a cohort of 17 patients, each with at least one plaque in the carotid or ascending aortic arteries. In total, 51 calcified (HU > 110) and 16 non-calcified plaque lesions (HU < 110) were analyzed. The lesion-to-background ratio (LBR) and the relative change of LBR (ΔLBR) were measured on PET. RESULTS Following PVC, LBR of the spheres (NEMA phantom) was within 10% of the original values. LBR of the thoracic lesions increased by 155% to 440% when the LP-PVC method was applied to the PET images. In patients, PVC increased the LBR in both calcified [mean = 78% (-8% to 227%)] and non-calcified plaques [mean = 41%, (-9%-104%)]. CONCLUSIONS PVC helps to improve LBR of plaque-type lesions in both phantom studies and clinical patients. Better results were obtained when the PVC method was applied to images reconstructed with point spread function modeling.
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Affiliation(s)
- Jacobo Cal-Gonzalez
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, General Hospital Vienna, Waehringer Guertel 18-20/4L, 1090, Vienna, Austria.
| | - Xiang Li
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Daniel Heber
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Ivo Rausch
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, General Hospital Vienna, Waehringer Guertel 18-20/4L, 1090, Vienna, Austria
| | - Stephen C Moore
- Division of Nuclear Medicine, Department of Radiology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, USA
| | - Klaus Schäfers
- European Institute for Molecular Imaging, University of Münster, Münster, Germany
| | - Marcus Hacker
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Thomas Beyer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, General Hospital Vienna, Waehringer Guertel 18-20/4L, 1090, Vienna, Austria
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19
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Shigemoto Y, Sone D, Imabayashi E, Maikusa N, Okamura N, Furumoto S, Kudo Y, Ogawa M, Takano H, Yokoi Y, Sakata M, Tsukamoto T, Kato K, Sato N, Matsuda H. Dissociation of Tau Deposits and Brain Atrophy in Early Alzheimer's Disease: A Combined Positron Emission Tomography/Magnetic Resonance Imaging Study. Front Aging Neurosci 2018; 10:223. [PMID: 30072890 PMCID: PMC6058018 DOI: 10.3389/fnagi.2018.00223] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 06/29/2018] [Indexed: 11/13/2022] Open
Abstract
The recent advent of tau-specific positron emission tomography (PET) has enabled in vivo assessment of tau pathology in Alzheimer’s disease (AD). However, because PET scanners have limited spatial resolution, the measured signals of small brain structures or atrophied areas are underestimated by partial volume effects (PVEs). The aim of this study was to determine whether partial volume correction (PVC) improves the precision of measures of tau deposits in early AD. We investigated tau deposits in 18 patients with amyloid-positive early AD and in 36 amyloid-negative healthy controls using 18F-THK5351 PET. For PVC, we applied the SPM toolbox PETPVE12. The PET images were then spatially normalized and subjected to voxel-based group analysis using SPM12 for comparison between the early AD patients and healthy controls. We also compared these two groups in terms of brain atrophy using voxel-based morphometry of MRI. We found widespread neocortical tracer retention predominantly in the posterior cingulate and precuneus areas, but also in the inferior temporal lobes, inferior parietal lobes, frontal lobes, and occipital lobes in the AD patients compared with the controls. The pattern of tracer retention was similar between before and after PVC, suggesting that PVC had little effect on the precision of tau load measures. Gray matter atrophy was detected in the medial/lateral temporal lobes and basal frontal lobes in the AD patients. Interestingly, only a few associations were found between atrophy and tau deposits, even after PVC. In conclusion, PVC did not significantly affect 18F-THK5351 PET measures of tau deposits. This discrepancy between tau deposits and atrophy suggests that tau load precedes atrophy.
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Affiliation(s)
- Yoko Shigemoto
- Integrative Brain Imaging Center, National Center of Neurology and Psychiatry, Tokyo, Japan.,Department of Radiology, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Daichi Sone
- Integrative Brain Imaging Center, National Center of Neurology and Psychiatry, Tokyo, Japan.,Department of Psychiatry, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Etsuko Imabayashi
- Integrative Brain Imaging Center, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Norihide Maikusa
- Integrative Brain Imaging Center, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Nobuyuki Okamura
- Division of Pharmacology, Faculty of Medicine, Tohoku Medical and Pharmaceutical University, Sendai, Japan.,Division of Neuro-imaging, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
| | - Shozo Furumoto
- Division of Radiopharmaceutical Chemistry, Cyclotron and Radioisotope Center, Tohoku University, Sendai, Japan
| | - Yukitsuka Kudo
- Division of Neuro-imaging, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
| | - Masayo Ogawa
- Integrative Brain Imaging Center, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Harumasa Takano
- Integrative Brain Imaging Center, National Center of Neurology and Psychiatry, Tokyo, Japan.,Department of Psychiatry, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Yuma Yokoi
- Department of Psychiatry, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Masuhiro Sakata
- Department of Psychiatry, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Tadashi Tsukamoto
- Department of Neurology, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Koichi Kato
- Integrative Brain Imaging Center, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Noriko Sato
- Department of Radiology, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Hiroshi Matsuda
- Integrative Brain Imaging Center, National Center of Neurology and Psychiatry, Tokyo, Japan
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20
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Kurzhunov D, Borowiak R, Reisert M, Özen AC, Bock M. Direct estimation of 17 O MR images (DIESIS) for quantification of oxygen metabolism in the human brain with partial volume correction. Magn Reson Med 2018; 80:2717-2725. [PMID: 29770486 DOI: 10.1002/mrm.27224] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 02/27/2018] [Accepted: 03/27/2018] [Indexed: 12/20/2022]
Abstract
PURPOSE To provide a data post-processing method that corrects for partial volume effects (PVE) and fast <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow><mml:msubsup><mml:mi>T</mml:mi> <mml:mn>2</mml:mn> <mml:mo>*</mml:mo></mml:msubsup> </mml:mrow> </mml:math> decay in dynamic 17 O MRI for the mapping of cerebral metabolic rates of oxygen consumption (CMRO2 ). METHODS CMRO2 is altered in neurodegenerative diseases and tumors and can be measured after 17 O gas inhalation using dynamic 17 O MRI. CMRO2 quantification is difficult because of PVE. To correct for PVE, a direct estimation of the MR images (DIESIS) method is proposed and used in 4 dynamic 17 O MRI data sets of a healthy volunteer acquired on a 3T MRI system. With DIESIS, 17 O MR signal time curves in selected regions were directly estimated based on parcellation of a coregistered 1 H MPRAGE image. RESULTS Profile likelihood analysis of the DIESIS method showed identifiability of CMRO2 . In white matter (WM), DIESES reduced CMRO2 from 0.97 ± 0.25 µmol/gtissue /min with Kaiser-Bessel gridding reconstruction to 0.85 ± 0.21 µmol/gtissue /min, whereas in gray matter (GM) it increases from 1.3 ± 0.31 µmol/gtissue /min to 1.86 ± 0.36 µmol/gtissue /min; both values are closer to the literature values from the 15 O-PET studies. CONCLUSION DIESIS provided an increased separation of CMRO2 values in GM and WM brain regions and corrected for partial volume effects in 17 O-MRI inhalation experiments. DIESIS could also be applied to more heterogeneous tissues such as glioblastomas if subregions of the tumor can be represented as additional parcels.
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Affiliation(s)
- Dmitry Kurzhunov
- Department of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Robert Borowiak
- Department of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Marco Reisert
- Department of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ali Caglar Özen
- Department of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,German Cancer Consortium Partner Site Freiburg, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Michael Bock
- Department of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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Tran-Gia J, Lassmann M. Optimizing Image Quantification for 177Lu SPECT/CT Based on a 3D Printed 2-Compartment Kidney Phantom. J Nucl Med 2017; 59:616-624. [PMID: 29097409 DOI: 10.2967/jnumed.117.200170] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 10/16/2017] [Indexed: 01/18/2023] Open
Abstract
The aim of this work was to find an optimal setup for activity determination of 177Lu-based SPECT/CT imaging reconstructed with 2 commercially available methods (xSPECT Quant and Flash3D). For this purpose, 3-dimensional (3D)-printed phantoms of different geometries were manufactured, different partial-volume correction (PVC) methods were applied, and the accuracy of the activity determination was evaluated. Methods: A 2-compartment kidney phantom (70% cortical and 30% medullary compartment), a sphere, and an ellipsoid of equal volumes were 3D printed, filled with 177Lu, and scanned with a SPECT/CT system. Reconstructions were performed with xSPECT and Flash3D. Different PVC methods were applied to find an optimal quantification setup: method 1 was a geometry-specific recovery coefficient based on the 3D printing model, method 2 was a geometry-specific recovery coefficient based on the low-dose CT scan, method 3 was an enlarged volume of interest including spilled-out counts, method 4 was activity concentration in the peak milliliter applied to the entire CT-based volume, and method 5 was a fixed threshold of 42% of the maximum in a large volume containing the object of interest. Additionally, the influence of postreconstruction gaussian filtering was investigated. Results: Although the recovery coefficients of sphere and ellipsoid differed by only 0.7%, a difference of 31.7% was observed between the sphere and the renal cortex phantoms. Without postfiltering, the model-based recovery coefficients (methods 1 and 2) resulted in the best accuracies (xSPECT, 1.5%; Flash3D, 10.3%), followed by the enlarged volume (method 3) (xSPECT, 8.5%; Flash3D, 13.0%). The peak-milliliter method (method 4) showed large errors only for sphere and ellipsoid (xSPECT, 23.4%; Flash3D, 21.6%). Applying a 42% threshold (method 5) led to the largest quantification errors (xSPECT, 32.3%; Flash3D, 46.7%). After postfiltering, a general increase in the errors was observed. Conclusion: In this work, 3D printing was used as a prototyping technique for a geometry-specific investigation of SPECT/CT reconstruction parameters and PVC methods. The optimal setup for activity determination was found to be an unsmoothed SPECT/CT reconstruction in combination with a recovery coefficient based on the low-dose CT. The difference between spheric and renal recovery coefficients suggests that the typically applied volume-dependent but only sphere-based recovery coefficient lookup tables should be replaced by a more geometry-specific alternative.
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Affiliation(s)
- Johannes Tran-Gia
- Department of Nuclear Medicine, University of Würzburg, Würzburg, Germany
| | - Michael Lassmann
- Department of Nuclear Medicine, University of Würzburg, Würzburg, Germany
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22
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Turco A, Nuyts J, Duchenne J, Gheysens O, Voigt JU, Claus P, Vunckx K. Analysis of partial volume correction on quantification and regional heterogeneity in cardiac PET. J Nucl Cardiol 2020; 27:62-70. [PMID: 28233192 DOI: 10.1007/s12350-016-0773-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 09/29/2022]
Abstract
BACKGROUND The partial volume correction (PVC) of cardiac PET datasets using anatomical side information during reconstruction is appealing but not straightforward. Other techniques, which do not make use of additional anatomical information, could be equally effective in improving the reconstructed myocardial activity. METHODS Resolution modeling in combination with different noise suppressing priors was evaluated as a means to perform PVC. Anatomical priors based on a high-resolution CT are compared to non-anatomical, edge-preserving priors (relative difference and total variation prior). The study is conducted on ex vivo datasets from ovine hearts. A simulation study additionally clarifies the relationship between prior effectiveness and myocardial wall thickness. RESULTS Simple resolution modeling during data reconstruction resulted in over- and underestimation of activity, which hampers the absolute left ventricular quantification when compared to the ground truth. Both the edge-preserving and the anatomy-based PVC techniques improve the absolute quantification, with comparable results (Student t-test, P = .17). The relative tracer distribution was preserved with any reconstruction technique (repeated ANOVA, P = .98). CONCLUSIONS The use of edge-preserving priors emerged as optimal choice for quantification of tracer uptake in the left ventricular wall of the available datasets. Anatomical priors visually outperformed edge-preserving priors when the thinnest structures were of interest.
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Ahlgren A, Wirestam R, Lind E, Ståhlberg F, Knutsson L. A linear mixed perfusion model for tissue partial volume correction of perfusion estimates in dynamic susceptibility contrast MRI: Impact on absolute quantification, repeatability, and agreement with pseudo-continuous arterial spin labeling. Magn Reson Med 2016; 77:2203-2214. [PMID: 27321696 DOI: 10.1002/mrm.26305] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 05/20/2016] [Accepted: 05/20/2016] [Indexed: 11/07/2022]
Abstract
PURPOSE The partial volume effect (PVE) is an important source of bias in brain perfusion measurements. The impact of tissue PVEs in perfusion measurements with dynamic susceptibility contrast MRI (DSC-MRI) has not yet been well established. The purpose of this study was to suggest a partial volume correction (PVC) approach for DSC-MRI and to study how PVC affects DSC-MRI perfusion results. METHODS A linear mixed perfusion model for DSC-MRI was derived and evaluated by way of simulations. Twenty healthy volunteers were scanned twice, including DSC-MRI, arterial spin labeling (ASL), and partial volume measurements. Two different algorithms for PVC were employed and assessed. RESULTS Simulations showed that the derived model had a tendency to overestimate perfusion values in voxels with high fractions of cerebrospinal fluid. PVC reduced the tissue volume dependence of DSC-MRI perfusion values from 44.4% to 4.2% in gray matter and from 55.3% to 14.2% in white matter. One PVC method significantly improved the voxel-wise repeatability, but PVC did not improve the spatial agreement between DSC-MRI and ASL perfusion maps. CONCLUSION Significant PVEs were found for DSC-MRI perfusion estimates, and PVC successfully reduced those effects. The findings suggest that PVC might be an important consideration for DSC-MRI applications. Magn Reson Med 77:2203-2214, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- André Ahlgren
- Department of Medical Radiation Physics, Lund University, Lund, Sweden
| | - Ronnie Wirestam
- Department of Medical Radiation Physics, Lund University, Lund, Sweden
| | - Emelie Lind
- Department of Medical Radiation Physics, Lund University, Lund, Sweden
| | - Freddy Ståhlberg
- Department of Medical Radiation Physics, Lund University, Lund, Sweden.,Department of Diagnostic Radiology, Lund University, Lund, Sweden.,Lund University Bioimaging Center, Lund University, Lund, Sweden
| | - Linda Knutsson
- Department of Medical Radiation Physics, Lund University, Lund, Sweden
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Long Z, Dyke JP, Ma R, Huang CC, Louis ED, Dydak U. Reproducibility and effect of tissue composition on cerebellar γ-aminobutyric acid (GABA) MRS in an elderly population. NMR Biomed 2015; 28:1315-23. [PMID: 26314380 PMCID: PMC4594865 DOI: 10.1002/nbm.3381] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Revised: 07/22/2015] [Accepted: 07/24/2015] [Indexed: 05/06/2023]
Abstract
MRS provides a valuable tool for the non-invasive detection of brain γ-aminobutyric acid (GABA) in vivo. GABAergic dysfunction has been observed in the aging cerebellum. The study of cerebellar GABA changes is of considerable interest in understanding certain age-related motor disorders. However, little is known about the reproducibility of GABA MRS in an aged population. Therefore, this study aimed to explore the feasibility and reproducibility of GABA MRS in the aged cerebellum at 3.0 T and to examine the effect of differing tissue composition on GABA measurements. MRI and (1)H MRS examinations were performed on 10 healthy elderly volunteers (mean age, 75.2 ± 6.5 years) using a 3.0-T Siemens Tim Trio scanner. Among them, five subjects were scanned twice to assess the short-term reproducibility. The MEGA-PRESS (Mescher-Garwood point-resolved spectroscopy) J-editing sequence was used for GABA detection in two volumes of interest (VOIs) in the left and right cerebellar dentate. MRS data processing and quantification were performed with LCModel 6.3-0L using two separate basis sets, generated from density matrix simulations using published values for chemical shifts and J couplings. Raw metabolite levels from LCModel outputs were corrected for cerebrospinal fluid contamination and relaxation. GABA-edited spectra yielded robust and stable GABA measurements with averaged intra-individual coefficients of variation for corrected GABA+ between 4.0 ± 2.8% and 13.4 ± 6.3%, and inter-individual coefficients of variation between 12.6% and 24.2%. In addition, there was a significant correlation between GABA+ obtained with the two LCModel basis sets. Overall, our results demonstrated the feasibility and reproducibility of cerebellar GABA-edited MRS at 3.0 T in an elderly population. This information might be helpful for studies using this technique to study GABA changes in normal or diseased aging brain, e.g. for power calculations and the interpretation of longitudinal observations.
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Affiliation(s)
- Zaiyang Long
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | - Jonathan P. Dyke
- Department of Radiology, Weill Cornell Medical College, New York, NY, USA
| | - Ruoyun Ma
- School of Health Sciences, Purdue University, West Lafayette, IN, USA
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Chaorui C. Huang
- Brain and Mind Research Institute, Weill Medical College of Cornell University, New York, NY, USA
| | - Elan D. Louis
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA
- Department of Chronic Disease Epidemiology, Yale School of Public Health, Yale University, New Haven, CT, USA
| | - Ulrike Dydak
- School of Health Sciences, Purdue University, West Lafayette, IN, USA
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA
- Correspondence to: U. Dydak, School of Health Sciences, Purdue University, West Lafayette, IN, 47907, USA.
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Abstract
In Positron Emission Tomography, there are several causes of quantitative inaccuracy, such as partial volume or spillover effects. The impact of these effects is greater when using radionuclides that have a large positron range, e.g. (68)Ga and (124)I, which have been increasingly used in the clinic. We have implemented and evaluated a local projection algorithm (LPA), originally evaluated for SPECT, to compensate for both partial-volume and spillover effects in PET. This method is based on the use of a high-resolution CT or MR image, co-registered with a PET image, which permits a high-resolution segmentation of a few tissues within a volume of interest (VOI) centered on a region within which tissue-activity values need to be estimated. The additional boundary information is used to obtain improved activity estimates for each tissue within the VOI, by solving a simple inversion problem. We implemented this algorithm for the preclinical Argus PET/CT scanner and assessed its performance using the radionuclides (18)F, (68)Ga and (124)I. We also evaluated and compared the results obtained when it was applied during the iterative reconstruction, as well as after the reconstruction as a postprocessing procedure. In addition, we studied how LPA can help to reduce the 'spillover contamination', which causes inaccurate quantification of lesions in the immediate neighborhood of large, 'hot' sources. Quantification was significantly improved by using LPA, which provided more accurate ratios of lesion-to-background activity concentration for hot and cold regions. For (18)F, the contrast was improved from 3.0 to 4.0 in hot lesions (when the true ratio was 4.0) and from 0.16 to 0.06 in cold lesions (true ratio = 0.0), when using the LPA postprocessing. Furthermore, activity values estimated within the VOI using LPA during reconstruction were slightly more accurate than those obtained by post-processing, while also visually improving the image contrast and uniformity within the VOI.
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Affiliation(s)
- J. Cal-González
- Grupo de Física Nuclear, Dpto. de Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, CEI Moncloa, Spain
| | - S. C. Moore
- Division of Nuclear Medicine, Department of Radiology, Harvard Medical School and Brigham and Women’s Hospital. Boston, USA
| | - M.-A. Park
- Division of Nuclear Medicine, Department of Radiology, Harvard Medical School and Brigham and Women’s Hospital. Boston, USA
| | - J. L. Herraiz
- Grupo de Física Nuclear, Dpto. de Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, CEI Moncloa, Spain
- Madrid-MIT M+Visión Consortium, Research Lab. of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - J. J. Vaquero
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Spain
| | - M. Desco
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Spain
- Unidad de Medicina y Cirugía Experimental, Hospital General Universitario Gregorio Marañón, CIBERSAM, Madrid, Spain
| | - J. M. Udias
- Grupo de Física Nuclear, Dpto. de Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, CEI Moncloa, Spain
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26
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Malpas CB, Saling MM, Velakoulis D, Desmond P, Hicks RJ, O'Brien TJ. Longitudinal Partial Volume Correction in 2-[18F]-Fluoro-2-Deoxy-D-Glucose Positron Emission Tomography Studies of Alzheimer Disease. J Comput Assist Tomogr 2015; 39:559-64. [PMID: 26182225 PMCID: PMC6318788 DOI: 10.1097/rct.0000000000000256] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To investigate partial volume correction (PVC) of 2-[F]-fluoro-2-deoxy-D-glucose positron emission tomography in Alzheimer disease in a longitudinal context. METHODS A total of 115 participants were included, including 55 controls, 53 patients with mild cognitive impairment, and 7 patients with dementia of the Alzheimer type. Imaging was performed at baseline and 24 months. Partial volume corrected vs uncorrected rates of longitudinal change were compared for mesial temporal and cortical regions of interest. RESULTS Partial volume correction increased apparent uptake, and this effect was greater at 24 months compared with baseline. Partial volume correction decreased the rate of decline, causing an apparent increase in uptake at 24 months compared with baseline. This effect was correlated with the structural atrophy. CONCLUSIONS These findings suggest that applying PVC in a longitudinal context in Alzheimer disease might produce unpredictable results. Accordingly, both PVC corrected and uncorrected data should be reported to ensure that the results are physiologically plausible.
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Affiliation(s)
- Charles B. Malpas
- Melbourne Brain Centre, Royal Melbourne Hospital, Melbourne, Victoria, Australia
- Melbourne School of Psychological Sciences, University of Melbourne, Melbourne, Victoria, Australia
| | - Michael M. Saling
- Melbourne School of Psychological Sciences, University of Melbourne, Melbourne, Victoria, Australia
- Department of Neuropsychology, Austin Health, Austin, Australia
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, Austin Hospital, Austin, Australia
| | - Dennis Velakoulis
- Melbourne Brain Centre, Royal Melbourne Hospital, Melbourne, Victoria, Australia
- Melbourne Neuropsychiatry Centre, Royal Melbourne Hospital, Melbourne, Victoria, Australia
- Departments of Psychiatry, University of Melbourne, Melbourne, Victoria, Australia
| | - Patricia Desmond
- Melbourne Brain Centre, Royal Melbourne Hospital, Melbourne, Victoria, Australia
- Departments of Radiology, University of Melbourne, Melbourne, Victoria, Australia
- Departments of Radiology, Royal Melbourne Hospital, Melbourne, Victoria, Australia
| | - Rodney J. Hicks
- Departments of Radiology, University of Melbourne, Melbourne, Victoria, Australia
- The Sir Peter MacCallum Department of Oncology, the University of Melbourne, Melbourne, Victoria, Australia
| | - Terence J. O'Brien
- Melbourne Brain Centre, Royal Melbourne Hospital, Melbourne, Victoria, Australia
- Departments of Medicine, Royal Melbourne Hospital, Melbourne, Victoria, Australia
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Evans E, Buonincontri G, Izquierdo D, Methner C, Hawkes RC, Ansorge RE, Krieg T, Carpenter TA, Sawiak SJ. Combining MRI with PET for partial volume correction improves image-derived input functions in mice. IEEE Trans Nucl Sci 2015; 62:628-633. [PMID: 26213413 PMCID: PMC4510926 DOI: 10.1109/tns.2015.2433897] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Accurate kinetic modelling using dynamic PET requires knowledge of the tracer concentration in plasma, known as the arterial input function (AIF). AIFs are usually determined by invasive blood sampling, but this is prohibitive in murine studies due to low total blood volumes. As a result of the low spatial resolution of PET, image-derived input functions (IDIFs) must be extracted from left ventricular blood pool (LVBP) ROIs of the mouse heart. This is challenging because of partial volume and spillover effects between the LVBP and myocardium, contaminating IDIFs with tissue signal. We have applied the geometric transfer matrix (GTM) method of partial volume correction (PVC) to 12 mice injected with 18F-FDG affected by a Myocardial Infarction (MI), of which 6 were treated with a drug which reduced infarction size [1]. We utilised high resolution MRI to assist in segmenting mouse hearts into 5 classes: LVBP, infarcted myocardium, healthy myocardium, lungs/body and background. The signal contribution from these 5 classes was convolved with the point spread function (PSF) of the Cambridge split magnet PET scanner and a non-linear fit was performed on the 5 measured signal components. The corrected IDIF was taken as the fitted LVBP component. It was found that the GTM PVC method could recover an IDIF with less contamination from spillover than an IDIF extracted from PET data alone. More realistic values of Ki were achieved using GTM IDIFs, which were shown to be significantly different (p<0.05) between the treated and untreated groups.
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Affiliation(s)
- Eleanor Evans
- Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, UK, CB2 0QQ ( )
| | - Guido Buonincontri
- Wolfson Brain Imaging Centre and the Department of Medicine, University of Cambridge, Cambridge, UK, CB2 0QQ ( )
| | - David Izquierdo
- Athinoula A. Martinos Center for Biomedical Imaging, 149 Thirteenth Street, Suite 2301, Charlestown, MA, 02129 ( )
| | - Carmen Methner
- Department of Medicine, University of Cambridge and is now at Oregon Health and Science University, Portland, OR, 97239 ( )
| | - Rob C Hawkes
- Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, UK, CB2 0QQ ( )
| | - Richard E Ansorge
- Department of Physics, University of Cambridge, Cambridge, UK, CB3 0HE ( )
| | - Thomas Krieg
- Member of the Department of Medicine, University of Cambridge, Cambridge, UK, CB2 0QQ ( )
| | - T Adrian Carpenter
- Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, UK, CB2 0QQ ( )
| | - Stephen J Sawiak
- Member of both the Wolfson Brain Imaging Centre, and the Behavioural and Clinical Neurosciences Institute, University of Cambridge, Cambridge, UK, CB2 3EB ( )
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Ahlgren A, Wirestam R, Petersen ET, Ståhlberg F, Knutsson L. Partial volume correction of brain perfusion estimates using the inherent signal data of time-resolved arterial spin labeling. NMR Biomed 2014; 27:1112-1122. [PMID: 25066601 DOI: 10.1002/nbm.3164] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 05/19/2014] [Accepted: 06/13/2014] [Indexed: 06/03/2023]
Abstract
Quantitative perfusion MRI based on arterial spin labeling (ASL) is hampered by partial volume effects (PVEs), arising due to voxel signal cross-contamination between different compartments. To address this issue, several partial volume correction (PVC) methods have been presented. Most previous methods rely on segmentation of a high-resolution T1 -weighted morphological image volume that is coregistered to the low-resolution ASL data, making the result sensitive to errors in the segmentation and coregistration. In this work, we present a methodology for partial volume estimation and correction, using only low-resolution ASL data acquired with the QUASAR sequence. The methodology consists of a T1 -based segmentation method, with no spatial priors, and a modified PVC method based on linear regression. The presented approach thus avoids prior assumptions about the spatial distribution of brain compartments, while also avoiding coregistration between different image volumes. Simulations based on a digital phantom as well as in vivo measurements in 10 volunteers were used to assess the performance of the proposed segmentation approach. The simulation results indicated that QUASAR data can be used for robust partial volume estimation, and this was confirmed by the in vivo experiments. The proposed PVC method yielded probable perfusion maps, comparable to a reference method based on segmentation of a high-resolution morphological scan. Corrected gray matter (GM) perfusion was 47% higher than uncorrected values, suggesting a significant amount of PVEs in the data. Whereas the reference method failed to completely eliminate the dependence of perfusion estimates on the volume fraction, the novel approach produced GM perfusion values independent of GM volume fraction. The intra-subject coefficient of variation of corrected perfusion values was lowest for the proposed PVC method. As shown in this work, low-resolution partial volume estimation in connection with ASL perfusion estimation is feasible, and provides a promising tool for decoupling perfusion and tissue volume.
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Affiliation(s)
- André Ahlgren
- Department of Medical Radiation Physics, Lund University, Lund, Sweden
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29
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Muellauer J, Willimayer R, Goertzen AL, Wanek T, Langer O, Birkfellner W, Kuntner C. 18F, 11C and 68Ga in small animal PET imaging. Evaluation of partial volume correction methods. Nuklearmedizin 2014; 52:250-61. [PMID: 24337014 DOI: 10.3413/nukmed-0578-13-04] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 10/01/2013] [Indexed: 11/20/2022]
Abstract
AIM The partial volume effect (PVE) significantly affects quantitative accuracy in PET. In this study we used a micro-hollow sphere phantom filled with 18F, 11C or 68Ga to evaluate different partial volume correction methods (PVC). Additionally, phantom data were applied on rat brain scans to evaluate PVC methods on in vivo datasets. METHODS The four spheres (7.81, 6.17, 5.02, 3.90 mm inner diameter) and the background region were filled to give sphere-to-background (sph/bg) activity ratios of 20 : 1, 10 : 1, 5 : 1 and 2 : 1. Two different acquisition and reconstruction protocols and three radionuclides were evaluated using a small animal PET scanner. From the obtained images the recovery coefficients (RC) and contrast recovery coefficients (CRC) for the different sph/bg ratios were calculated. Three methods for PVC were evaluated: a RC based, a CRC based and a volume of interest (VOI) based method. The most suitable PVC methods were applied to in vivo rat brain data. RESULTS RCs were shown to be dependent on the radionuclide used, with the highest values for 18F, followed by 11C and 68Ga. The calculated mean CRCs were generally lower than the corresponding mean RCs. Application of the different PVC methods to rat brain data led to a strong increase in time-activity curves for the smallest brain region (entorhinal cortex), whereas the lowest increase was obtained for the largest brain region (cerebellum). CONCLUSION This study was able to show the importance and impact of PVE and the limitations of several PVC methods when performing quantitative measurements in small structures.
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Affiliation(s)
| | | | | | | | | | | | - C Kuntner
- Claudia Kuntner, Biomedical Systems, Health & Environment Department, AIT Austrian Institute of Technology GmbH, Seibersdorf, Austria, Tel. +43/505 50 34 71, Fax +43/505 50 34 73, E-mail:
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30
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Tsai SY, Wang WC, Lin YR. Comparison of sagittal and transverse echo planar spectroscopic imaging on the quantification of brain metabolites. J Neuroimaging 2014; 25:167-174. [PMID: 24593139 DOI: 10.1111/jon.12087] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 11/25/2013] [Accepted: 12/06/2013] [Indexed: 11/29/2022] Open
Abstract
PURPOSE We quantitatively compared sagittal and transverse echo planar spectroscopic imaging (EPSI) on the quantification of metabolite concentrations with consideration of tissue variation. A quantification strategy is proposed to collect the necessary information for quantification of concentrations in a minimized acquisition time. METHODS Six transverse and six sagittal EPSI data were collected on healthy volunteers. Metabolite concentrations of N-acetyl-aspartate (NAA), total creatine (tCr), total choline (tCho), myo-inositol (mI), and glutamate and glutamine complex (Glx) were quantified using water scaling with partial volume and relaxation correction. Linear regression analysis was performed to extract concentrations in gray matter (GM) and white matter (WM). The inter- and intrasubject coefficients of variance (CV) were estimated. RESULTS Concentrations and fitting errors of sagittal and transverse EPSI were at same level. GM to WM contrast of concentrations was found in NAA, tCr, and tCho. The intersubject CVs revealed greater variability in the sagittal EPSI than in the transverse EPSI. The intrasubject CVs of the transverse EPSI were below 5% for NAA, tCr, and tCho. CONCLUSION We showed that quantified concentrations of sagittal and transverse EPSI after partial volume correction are comparable and reproducible. The proposed quantification strategy can be conveniently adapted into various MRI protocols.
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Affiliation(s)
- Shang-Yueh Tsai
- Graduate Institute of Applied Physics, National Chengchi University, Taipei, Taiwan.,Mind, Brain and Learning Center, National Chengchi University, Taipei, Taiwan
| | - Woan-Chyi Wang
- Graduate Institute of Applied Physics, National Chengchi University, Taipei, Taiwan
| | - Yi-Ru Lin
- Department of Electronic and Computer Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan
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Knowles SM, Zettlitz KA, Tavaré R, Rochefort MM, Salazar FB, Stout DB, Yazaki PJ, Reiter RE, Wu AM. Quantitative immunoPET of prostate cancer xenografts with 89Zr- and 124I-labeled anti-PSCA A11 minibody. J Nucl Med 2014; 55:452-9. [PMID: 24504052 DOI: 10.2967/jnumed.113.120873] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
UNLABELLED Prostate stem cell antigen (PSCA) is expressed on the cell surface in 83%-100% of local prostate cancers and 87%-100% of prostate cancer bone metastases. In this study, we sought to develop immunoPET agents using (124)I- and (89)Zr-labeled anti-PSCA A11 minibodies (scFv-CH3 dimer, 80 kDa) and evaluate their use for quantitative immunoPET imaging of prostate cancer. METHODS A11 anti-PSCA minibody was alternatively labeled with (124)I- or (89)Zr-desferrioxamine and injected into mice bearing either matched 22Rv1 and 22Rv1×PSCA or LAPC-9 xenografts. Small-animal PET data were obtained and quantitated with and without recovery coefficient-based partial-volume correction, and the results were compared with ex vivo biodistribution. RESULTS Rapid and specific localization to PSCA-positive tumors and high-contrast imaging were observed with both (124)I- and (89)Zr-labeled A11 anti-PSCA minibody. However, the differences in tumor uptake and background uptake of the radiotracers resulted in different levels of imaging contrast. The nonresidualizing (124)I-labeled minibody had lower tumor uptake (3.62 ± 1.18 percentage injected dose per gram [%ID/g] 22Rv1×PSCA, 3.63 ± 0.59 %ID/g LAPC-9) than the residualizing (89)Zr-labeled minibody (7.87 ± 0.52 %ID/g 22Rv1×PSCA, 9.33 ± 0.87 %ID/g LAPC-9, P < 0.0001 for each), but the (124)I-labeled minibody achieved higher imaging contrast because of lower nonspecific uptake and better tumor-to-soft-tissue ratios (22Rv1×PSCA:22Rv1 positive-to-negative tumor, 13.31 ± 5.59 (124)I-A11 and 4.87 ± 0.52 (89)Zr-A11, P = 0.02). Partial-volume correction was found to greatly improve the correspondence between small-animal PET and ex vivo quantification of tumor uptake for immunoPET imaging with both radionuclides. CONCLUSION Both (124)I- and (89)Zr-labeled A11 anti-PSCA minibody showed high-contrast imaging of PSCA expression in vivo. However, the (124)I-labeled A11 minibody was found to be the superior imaging agent because of lower nonspecific uptake and higher tumor-to-soft-tissue contrast. Partial-volume correction was found to be essential for robust quantification of immunoPET imaging with both (124)I- and (89)Zr-labeled A11 minibody.
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Affiliation(s)
- Scott M Knowles
- Crump Institute for Molecular Imaging, Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at the University of California-Los Angeles, Los Angeles, California
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Kim E, Shidahara M, Tsoumpas C, McGinnity CJ, Kwon JS, Howes OD, Turkheimer FE. Partial volume correction using structural-functional synergistic resolution recovery: comparison with geometric transfer matrix method. J Cereb Blood Flow Metab 2013; 33:914-20. [PMID: 23486292 DOI: 10.1038/jcbfm.2013.29] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We validated the use of a novel image-based method for partial volume correction (PVC), structural-functional synergistic resolution recovery (SFS-RR) for the accurate quantification of dopamine synthesis capacity measured using [(18)F]DOPA positron emission tomography. The bias and reliability of SFS-RR were compared with the geometric transfer matrix (GTM) method. Both methodologies were applied to the parametric maps of [(18)F]DOPA utilization rates (ki(cer)). Validation was first performed by measuring repeatability on test-retest scans. The precision of the methodologies instead was quantified using simulated [(18)F]DOPA images. The sensitivity to the misspecification of the full-width-half-maximum (FWHM) of the scanner point-spread-function on both approaches was also assessed. In the in-vivo data, the ki(cer) was significantly increased by application of both PVC procedures while the reliability remained high (intraclass correlation coefficients >0.85). The variability was not significantly affected by either PVC approach (<10% variability in both cases). The corrected ki(cer) was significantly influenced by the FWHM applied in both the acquired and simulated data. This study shows that SFS-RR can effectively correct for partial volume effects to a comparable degree to GTM but with the added advantage that it enables voxelwise analyses, and that the FWHM used can affect the PVC result indicating the importance of accurately calibrating the FWHM used in the recovery model.
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Wallstén E, Axelsson J, Sundström T, Riklund K, Larsson A. Subcentimeter tumor lesion delineation for high-resolution 18F-FDG PET images: optimizing correction for partial-volume effects. J Nucl Med Technol 2013; 41:85-91. [PMID: 23658206 DOI: 10.2967/jnmt.112.117234] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
UNLABELLED In PET, partial-volume effects cause errors in estimation of size and activity for small objects with radiopharmaceutical uptake. Recent methods for image reconstruction, compared with traditional reconstruction techniques, include algorithms for resolution recovery that result in images with higher resolution and enable quantification of size and activity of smaller objects. The purpose of this study was to evaluate a combination of 2 algorithms for volume delineation and partial-volume correction on uptake volumes smaller than 0.7 mL using image reconstruction algorithms with and without resolution recovery. METHODS Volumes of interests (VOIs) were delineated using a threshold intensity calculated as a weighted sum of tumor and background intensities. These VOIs were used for calculating correction factors by convolving a tumor mask with the system point-spread function. The methods algorithms were evaluated using a phantom constructed from 5 small different-sized balloons filled with (18)F-FDG in background activity. Six different backgrounds were used. Data were acquired using a PET/CT scanner, and the images were reconstructed using 2 iterative algorithms, one of which used a resolution recovery algorithm. RESULTS For the images reconstructed using the resolution recovery algorithm, the method for volume delineation resulted in VOI sizes that were correct within 1 SD for all balloons of a volume of 0.35 mL (equivalent diameter, 8.8 mm) and larger, in all backgrounds. For the images reconstructed without resolution recovery, the VOI sizes were background-dependent and generally less accurate. Correct volume delineations generally led to accurate activity estimates. CONCLUSION The algorithms tested on the phantom developed for this study could, for this PET camera and these reconstruction algorithms, be used for accurate volume delineation and activity quantification of lesions 0.35 mL and larger.
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Affiliation(s)
- Elin Wallstén
- Department of Radiation Sciences, Umeå University, Umeå, Sweden.
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Wang H, Fei B. An MR image-guided, voxel-based partial volume correction method for PET images. Med Phys 2012; 39:179-95. [PMID: 22225287 PMCID: PMC3261055 DOI: 10.1118/1.3665704] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Revised: 11/07/2011] [Accepted: 11/07/2011] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Partial volume effect in positron emission tomography (PET) can cause incorrect quantification of radiopharmaceutical uptake in functional imaging. A PET partial volume correction method is presented to attenuate partial volume blurring and to yield voxel-based corrected PET images. METHODS By modeling partial volume effect as a convolution of point spread function of the PET scanner, the reconstructed PET images are corrected by iterative deconvolution with an edge-preserving smoothness constraint. The constraint is constructed to restore discontinuities extracted from coregistered MR images but maintains the smoothness in radioactivity distribution. The correction is implemented in a Bayesian deconvolution framework and is solved by a conjugate gradient method. The performance of the method was compared with the geometric transfer matrix (GTM) method on a simulated dataset. The method was evaluated on synthesized brain FDG-PET data and phantom MRI-PET experiments. RESULTS The true PET activity of objects with a size of greater than the full-width at half maximum of the point spread function has been effectively restored in the simulated data. The partial volume correction method is quantitatively comparable to the GTM method. For synthesized FDG-PET with true activity 0 μci/cc for cerebrospinal fluid (CSF), 228 μci/cc for white matter (WM), and 621 μci/cc for gray matter (GM), the method has improved the radioactivity quantification from 186 ± 16 μci/cc to 30 ± 7 μci/cc in CSF, 317 ± 15 μci/cc to 236 ± 10 μci/cc for WM, 438 ± 4 μci/cc to 592 ± 5 μci/cc for GM. Both visual and quantitative assessments show improvement of partial volume correction in the synthesized and phantom experiments. CONCLUSIONS The partial volume correction method improves the quantification of PET images. The method is comparable to the GTM method but does not need MR image segmentation or prior tracer distribution information. The voxel-based method can be particularly useful for combined PET/MRI studies.
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Affiliation(s)
- Hesheng Wang
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, Georgia 30329, USA
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Johnson NP, Sdringola S, Gould KL. Partial volume correction incorporating Rb-82 positron range for quantitative myocardial perfusion PET based on systolic-diastolic activity ratios and phantom measurements. J Nucl Cardiol 2011; 18:247-58. [PMID: 21184208 PMCID: PMC3069317 DOI: 10.1007/s12350-010-9327-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2010] [Accepted: 11/26/2010] [Indexed: 11/30/2022]
Abstract
BACKGROUND Quantitative myocardial PET perfusion imaging requires partial volume corrections. METHODS Patients underwent ECG-gated, rest-dipyridamole, myocardial perfusion PET using Rb-82 decay corrected in Bq/cc for diastolic, systolic, and combined whole cycle ungated images. Diastolic partial volume correction relative to systole was determined from the systolic/diastolic activity ratio, systolic partial volume correction from phantom dimensions comparable to systolic LV wall thicknesses and whole heart cycle partial volume correction for ungated images from fractional systolic-diastolic duration for systolic and diastolic partial volume corrections. RESULTS For 264 PET perfusion images from 159 patients (105 rest-stress image pairs, 54 individual rest or stress images), average resting diastolic partial volume correction relative to systole was 1.14 ± 0.04, independent of heart rate and within ±1.8% of stress images (1.16 ± 0.04). Diastolic partial volume corrections combined with those for phantom dimensions comparable to systolic LV wall thickness gave an average whole heart cycle partial volume correction for ungated images of 1.23 for Rb-82 compared to 1.14 if positron range were negligible as for F-18. CONCLUSION Quantitative myocardial PET perfusion imaging requires partial volume correction, herein demonstrated clinically from systolic/diastolic absolute activity ratios combined with phantom data accounting for Rb-82 positron range.
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Affiliation(s)
- Nils P. Johnson
- Division of Cardiology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL USA
| | - Stefano Sdringola
- Division of Cardiology, Department of Medicine, Weatherhead P.E.T. Center For Preventing and Reversing Atherosclerosis, University of Texas Medical School and Memorial Hermann Hospital, 6431 Fannin St., Room 4.256 MSB, Houston, TX 77030 USA
| | - K. Lance Gould
- Division of Cardiology, Department of Medicine, Weatherhead P.E.T. Center For Preventing and Reversing Atherosclerosis, University of Texas Medical School and Memorial Hermann Hospital, 6431 Fannin St., Room 4.256 MSB, Houston, TX 77030 USA
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Kegeles LS, Slifstein M, Xu X, Urban N, Thompson JL, Moadel T, Harkavy-Friedman JM, Gil R, Laruelle M, Abi-Dargham A. Striatal and extrastriatal dopamine D2/D3 receptors in schizophrenia evaluated with [18F]fallypride positron emission tomography. Biol Psychiatry 2010; 68:634-41. [PMID: 20673873 PMCID: PMC2952433 DOI: 10.1016/j.biopsych.2010.05.027] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2009] [Revised: 05/17/2010] [Accepted: 05/18/2010] [Indexed: 11/19/2022]
Abstract
BACKGROUND Alterations in dopamine D(2)/D(3) receptor binding have been reported in schizophrenia, and a meta-analysis of imaging studies has shown a modest elevation in striatum. Newer radioligands now allow the assessment of these receptors in extrastriatal regions. We used positron emission tomography with [(18)F]fallypride to evaluate D(2)/D(3) receptors in both striatal and extrastriatal regions in schizophrenia. METHODS Twenty-one patients with schizophrenia and 22 matched healthy control subjects were scanned with an ECAT EXACT HR+ camera. Two-tissue compartment modeling and the reference tissue method gave binding potentials relative to nondisplaceable uptake, total plasma concentration, and free plasma concentration. These were compared between groups in five striatal and eight extrastriatal regions. Several regional volumes were lower in the patient group, and positron emission tomography data were corrected for partial volume effects. RESULTS Binding potential values differed in three regions between groups. Values for binding potential relative to nondisplaceable uptake from two-tissue compartment modeling in patients and control subjects, respectively, were 28.7 ± 6.8 and 25.3 ± 4.3 in postcommissural caudate, 2.9 ± .7 and 2.6 ± .4 in thalamus, and 1.8 ± .5 and 2.1 ± .7 in uncus. Loss of D(2)/D(3) receptors with age was found in striatal and extrastriatal regions and was greater in neocortex. CONCLUSIONS Our study found selective alterations in D(2)/D(3) receptors in striatal and extrastriatal regions, consistent with some but not all previously published reports. As previously shown for the striatum, a more sensitive imaging approach for studying the role of dopamine in the pathophysiology of schizophrenia might be assessment of neurotransmitter levels rather than D(2)/D(3) receptor levels in extrastriatal regions.
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Affiliation(s)
- Lawrence S Kegeles
- Department of Psychiatry, Columbia University College of Physicians and Surgeons, and New York State Psychiatric Institute, New York 10032, USA.
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