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A Novel Automatic Approach for Calculation of the Specific Binding Ratio in [I-123]FP-CIT SPECT. Diagnostics (Basel) 2020; 10:diagnostics10050289. [PMID: 32397547 PMCID: PMC7277984 DOI: 10.3390/diagnostics10050289] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 05/07/2020] [Accepted: 05/07/2020] [Indexed: 11/22/2022] Open
Abstract
A fully automatic method for specific binding ratio (SBR) calculation in [123I]ioflupane single-photon emission computed tomography (SPECT) studies was proposed by creating volumes of interest of the striatum (VOIst) and reference region (VOIref) without manual handling to avoid operator-induced variability. The study involved 105 patients (72 ± 10 years) suspected of parkinsonian syndrome (PS) who underwent [123I]ioflupane SPECT. The 200 images from our previous study were used for evaluation and validation of the new program. All patients were classified into PS and non-PS groups according to the results of clinical follow-up. A trapezoidal volume of interest (VOIt) containing all striatal intensive counts was created automatically, followed by VOIst setting using the previous method. SBR values were calculated from the mean values of VOIst and VOIref determined by the whole brain outside of VOIt. The low count voxels in the VOIref were excluded using an appropriate threshold. The SBR values from the new method were compared with the previous semi-automatic method and the Tossici–Bolt (TB) method. The SBRs from the semi- and fully automatic methods showed a good linear correlation (r > 0.98). The areas under the curves (AUCs) of receiver operating characteristic analysis showed no significant difference between the two methods for both our previous (AUC > 0.99) and new (AUC > 0.95) data. The diagnostic accuracy of the two methods showed similar results (>92%), and both were better than the TB method. The proposed method successfully created the automatic VOIs and calculated SBR rapidly (9 ± 1 s/patient), avoiding operator-induced variability and providing objective SBR results.
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Croteau E, Lavallée É, Labbe SM, Hubert L, Pifferi F, Rousseau JA, Cunnane SC, Carpentier AC, Lecomte R, Bénard F. Image-derived input function in dynamic human PET/CT: methodology and validation with 11C-acetate and 18F-fluorothioheptadecanoic acid in muscle and 18F-fluorodeoxyglucose in brain. Eur J Nucl Med Mol Imaging 2010; 37:1539-50. [PMID: 20437239 PMCID: PMC2914861 DOI: 10.1007/s00259-010-1443-z] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Accepted: 03/08/2010] [Indexed: 01/05/2023]
Abstract
Purpose Despite current advances in PET/CT systems, blood sampling still remains the standard method to obtain the radiotracer input function for tracer kinetic modelling. The purpose of this study was to validate the use of image-derived input functions (IDIF) of the carotid and femoral arteries to measure the arterial input function (AIF) in PET imaging. The data were obtained from two different research studies, one using 18F-FDG for brain imaging and the other using 11C-acetate and 18F-fluoro-6-thioheptadecanoic acid (18F-FTHA) in femoral muscles. Methods The method was validated with two phantom systems. First, a static phantom consisting of syringes of different diameters containing radioactivity was used to determine the recovery coefficient (RC) and spill-in factors. Second, a dynamic phantom built to model bolus injection and clearance of tracers was used to establish the correlation between blood sampling, AIF and IDIF. The RC was then applied to the femoral artery data from PET imaging studies with 11C-acetate and 18F-FTHA and to carotid artery data from brain imaging with 18F-FDG. These IDIF data were then compared to actual AIFs from patients. Results With 11C-acetate, the perfusion index in the femoral muscle was 0.34±0.18 min−1 when estimated from the actual time–activity blood curve, 0.29±0.15 min−1 when estimated from the corrected IDIF, and 0.66±0.41 min−1 when the IDIF data were not corrected for RC. A one-way repeated measures (ANOVA) and Tukey’s test showed a statistically significant difference for the IDIF not corrected for RC (p<0.0001). With 18F-FTHA there was a strong correlation between Patlak slopes, the plasma to tissue transfer rate calculated using the true plasma radioactivity content and the corrected IDIF for the femoral muscles (vastus lateralis r=0.86, p=0.027; biceps femoris r=0.90, p=0.017). On the other hand, there was no correlation between the values derived using the AIF and those derived using the uncorrected IDIF. Finally, in the brain imaging study with 18F-FDG, the cerebral metabolic rate of glucose (CMRglc) measured using the uncorrected IDIF was consistently overestimated. The CMRglc obtained using blood sampling was 13.1±3.9 mg/100 g per minute and 14.0±5.7 mg/100 g per minute using the corrected IDIF (r2=0.90). Conclusion Correctly obtained, carotid and femoral artery IDIFs can be used as a substitute for AIFs to perform tracer kinetic modelling in skeletal femoral muscles and brain analyses.
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Affiliation(s)
- Etienne Croteau
- Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC Canada
- Sherbrooke Molecular Imaging Center, Centre de recherche clinique Étienne-LeBel, Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC Canada
| | - Éric Lavallée
- Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC Canada
- Sherbrooke Molecular Imaging Center, Centre de recherche clinique Étienne-LeBel, Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC Canada
| | - Sébastien M. Labbe
- Department of Medicine, Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC Canada
| | - Laurent Hubert
- Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC Canada
- Sherbrooke Molecular Imaging Center, Centre de recherche clinique Étienne-LeBel, Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC Canada
| | - Fabien Pifferi
- Research Center on Aging, Université de Sherbrooke, Sherbrooke, QC Canada
- Mécanismes Adaptatifs et Évolution, MNHN-CNRS, Brunoy, France
| | - Jacques A. Rousseau
- Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC Canada
- Sherbrooke Molecular Imaging Center, Centre de recherche clinique Étienne-LeBel, Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC Canada
| | - Stephen C. Cunnane
- Research Center on Aging, Université de Sherbrooke, Sherbrooke, QC Canada
- Department of Medicine, Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC Canada
| | - André C. Carpentier
- Department of Medicine, Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC Canada
| | - Roger Lecomte
- Department of Nuclear Medicine and Radiobiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC Canada
- Sherbrooke Molecular Imaging Center, Centre de recherche clinique Étienne-LeBel, Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC Canada
| | - François Bénard
- Division of Nuclear Medicine, Department of Radiology, University of British Columbia, Vancouver, BC Canada
- BC Cancer Agency, 675 West 10th Avenue, Vancouver, BC V5Z 1L3 Canada
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Kish SJ, Furukawa Y, Chang LJ, Tong J, Ginovart N, Wilson A, Houle S, Meyer JH. Regional distribution of serotonin transporter protein in postmortem human brain. Nucl Med Biol 2005; 32:123-8. [PMID: 15721757 DOI: 10.1016/j.nucmedbio.2004.10.001] [Citation(s) in RCA: 143] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2004] [Accepted: 10/07/2004] [Indexed: 10/25/2022]
Abstract
INTRODUCTION The primary approach in assessing the status of brain serotonin neurons in human conditions such as major depression and exposure to the illicit drug ecstasy has been the use of neuroimaging procedures involving radiotracers that bind to the serotonin transporter (SERT). However, there has been no consistency in the selection of a "SERT-free" reference region for the estimation of free and nonspecific binding, as occipital cortex, cerebellum and white matter have all been employed. OBJECTIVE AND METHODS To identify areas of human brain that might have very low SERT levels, we measured, by a semiquantitative Western blotting procedure, SERT protein immunoreactivity throughout the postmortem brain of seven normal adult subjects. RESULTS Serotonin transporter could be quantitated in all examined brain areas. However, the SERT concentration in cerebellar cortex and white matter were only at trace values, being approximately 20% of average cerebral cortex and 5% of average striatum values. CONCLUSION Although none of the examined brain areas are completely free of SERT, human cerebellar cortex has low SERT binding as compared to other examined brain regions, with the exception of white matter. Since the cerebellar cortical SERT binding is not zero, this region will not be a suitable reference region for SERT radioligands with very low free and nonspecific binding. For SERT radioligands with reasonably high free and nonspecific binding, the cerebellar cortex should be a useful reference region, provided other necessary radioligand assumptions are met.
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Affiliation(s)
- Stephen J Kish
- Human Neurochemical Pathology Laboratory, Centre for Addiction and Mental Health, Toronto, ON, Canada M5T 1R8.
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Langer O, Halldin C, Chou Y, Sandell J, Swahn C, Någren K, Perrone R, Berardi F, Leopoldo M, Farde L. Carbon-11 pb-12: an attempt to visualize the dopamine d(4) receptor in the primate brain with positron emission tomography. Nucl Med Biol 2000; 27:707-14. [PMID: 11150701 DOI: 10.1016/s0969-8051(00)00154-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The dopamine D(4) receptor (D(4)R) is expressed in low density in various extrastriatal brain regions. This receptor subtype is discussed in relation to the pathophysiology and treatment of schizophrenia but no selective positron emission tomography (PET) ligand is available to date to study the distribution in vivo. The arylpiperazine derivative N-[2-[4-(4-chlorophenyl)piperazin-1-yl]ethyl]-3-methoxybenzamide (PB-12) is a novel, high-affinity ( K(i)=0.040 nM) and selective D(4)R ligand. We radiolabeled PB-12 with carbon-11 (t(1/2) 20.4 min) by O-methylation of the corresponding desmethyl analogue N-[2-[4-(4-chlorophenyl)piperazin-1-yl]ethyl]-3-hydroxybenzamide (LM-190) with [(11)C]methyl triflate. Derivative LM-190 was prepared by condensing 3-hydroxybenzoic acid with the appropriate amine. For the radiolabeling, the incorporation yield was >90% and the total synthesis time including high performance liquid chromatography (HPLC) purification was about 35 min. The specific radioactivity of [(11)C]PB-12 at time of injection was 67-118 GBq x micromol(-1). PET studies in a cynomolgus monkey showed a high uptake and widespread distribution of radioactivity in the brain, including the neocortex and thalamus. About 40% of total radioactivity in plasma represented unchanged radioligand at 60 min after injection as determined by HPLC. Pretreatment with the D(4)R ligand 3-[[4-(4-chlorophenyl)piperazin-1-yl]methyl]-1H-pyrollo[2,3-b]pyridine (L-745,870) prior to radioligand injection failed to demonstrate receptor-specific binding in the monkey brain. Furthermore, the brain radioactivity distribution was left unaffected by pretreating with unlabeled PB-12. This failure to detect a D(4)R-specific signal may be related to a very low density of the D(4)R in primate brain, insufficient binding affinity of the radioligand, and a high background of nonspecific binding. It can be concluded from these findings that [(11)C]PB-12 is not suitable to visualize the D(4)R in the primate brain with PET.
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Affiliation(s)
- O Langer
- Karolinska Institute, Department of Clinical Neuroscience, Psychiatry Section, Karolinska Hospital, Stockholm, Sweden.
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