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See detail18F-FDG PET/CT in the Management of Aortitis.
Bruls, Samuel; Courtois, Audrey ULg; Nusgens-Richelle, Betty ULg et al

in Clinical nuclear medicine (2015)

BACKGROUND: Aortitis is a generic term defined as an inflammatory condition involving the aortic wall, of infectious or noninfectious origin. This inflammatory process may deteriorate the aortic wall ... [more ▼]

BACKGROUND: Aortitis is a generic term defined as an inflammatory condition involving the aortic wall, of infectious or noninfectious origin. This inflammatory process may deteriorate the aortic wall, resulting in potentially life-threatening vascular complications. Therefore, it is important to establish a diagnosis as early as possible. PATIENTS AND METHODS: During a 4-year period, 428 consecutive patients referred to our department for aortic diseases underwent FDG PET/CT examinations. Among these, 18 patients (4.2%) were suspected to have aortitis. All of them had an initial positive FDG PET/CT uptake occurring in the aorta and major branches as evaluated by visual analysis of images and assessed with the final diagnosis of aortitis. During follow-up, after surgery and/or upon immunosuppressive treatment, each of these patients underwent a second PET/CT that was compared with the initial evaluation. In all cases, normalization of FDG uptake was correlated with clinical improvement. CONCLUSIONS: Our study aimed to illustrate the potential clinical value of functional monitoring with PET/CT in the management of aortitis. FDG PET/CT constitutes a valuable imaging modality to establish an early diagnosis, monitor disease progression and treatment, and evaluate vascular complication and relapse. We highlight the importance of an early detection of inflammatory large-vessel pathology, which may represent a major threat. [less ▲]

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See detail18F-FDG Uptake Assessed by PET/CT in Abdominal Aortic Aneurysms Is Associated with Cellular and Molecular Alterations Prefacing Wall Deterioration and Rupture.
Courtois, Audrey ULg; Richelle, Betty ULg; Hustinx, Roland ULg et al

in Journal of Nuclear Medicine (The) (2013), 54

Rupture of abdominal aortic aneurysms (AAAs) leads to a significant morbidity and mortality in aging populations, and its prediction would be most beneficial to public health. Spots of positive uptake of ... [more ▼]

Rupture of abdominal aortic aneurysms (AAAs) leads to a significant morbidity and mortality in aging populations, and its prediction would be most beneficial to public health. Spots of positive uptake of 18F-FDG detected by PET are found in 12% of AAA patients (PET+), who are most often symptomatic and at high rupture risk. Comparing the 18F-FDG-positive site with a negative site from the same aneurysm and with samples collected from AAA patients with no 18F-FDG uptake should allow the discrimination of biologic alterations that would help in identifying markers predictive of rupture. METHODS: Biopsies of the AAA wall were obtained from patients with no 18F-FDG uptake (PET0, n = 10) and from PET+ patients (n = 8), both at the site of positive uptake and at a distant negative site of the aneurysmal wall. Samples were analyzed by immunohistochemistry, quantitative real-time polymerase chain reaction, and zymography. RESULTS: The sites of the aneurysmal wall with a positive 18F-FDG uptake were characterized by a strikingly increased number of adventitial inflammatory cells, highly proliferative, and by a drastic reduction of smooth muscle cells (SMCs) in the media as compared with their negative counterpart and with the PET0 wall. The expression of a series of genes involved in the maintenance and remodeling of the wall was significantly modified in the negative sites of PET+, compared with the PET0 wall, suggesting a systemic alteration of the aneurysmal wall. Furthermore, a striking increase of several matrix metalloproteinases (MMPs), notably the MMP1 and MMP13 collagenases, was observed in the positive sites, mainly in the adventitia. Moreover, PET+ patients were characterized by a higher circulating C-reactive protein. CONCLUSION: Positive 18F-FDG uptake in the aneurysmal wall is associated with an active inflammatory process characterized by a dense infiltrate of proliferating leukocytes in the adventitia and an increased circulating C-reactive protein. Moreover, a loss of SMC in the media and alterations of the expression of genes involved in the remodeling of adventitia and collagen degradation potentially participate in the weakening of the aneurysmal wall preceding rupture. [less ▲]

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See detail18F-fluoride PET/CT for assessing bone involvement in prostate and breast cancers
Withofs, Nadia ULg; Grayet, Benjamin ULg; Tancredi, Tino ULg et al

in Nuclear Medicine Communications (2011), 32(3), 168-176

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See detail18F-fluoro-L-tyrosine : a potential tracer for whole-body tumor imaging with PET.
HUSTINX, Roland ULg; LEMAIRE, C.; JERUSALEM, Guy ULg et al

in Journal of Nuclear Medicine (The) (2002), 43

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See detail18F-flutemetamol amyloid imaging in Alzheimer disease and mild cognitive impairment: a phase 2 trial.
Vandenberghe, R.; Van Laere, K.; Ivanoiu, A. et al

in Annals of Neurology (2010), 68(3), 319-329

Objective: The most widely studied positron emission tomography ligand for in vivo -amyloid imaging is 11CPittsburgh compound B (11C-PIB). Its availability, however, is limited by the need for an on-site ... [more ▼]

Objective: The most widely studied positron emission tomography ligand for in vivo -amyloid imaging is 11CPittsburgh compound B (11C-PIB). Its availability, however, is limited by the need for an on-site cyclotron. Validation of the 18F-labeled PIB derivative 18F-flutemetamol could significantly enhance access to this novel technology. Methods: Twenty-seven patients with early-stage clinically probable Alzheimer disease (AD), 20 with amnestic mild cognitive impairment (MCI), and 15 cognitively intact healthy volunteers (HVs) above and 10 HVs below 55 years of age participated. The primary endpoint was the efficacy of blinded visual assessments of 18F-flutemetamol scans in assigning subjects to a raised versus normal uptake category, with clinical diagnosis as the standard of truth (SOT). As secondary objectives, we determined the correlation between the regional standardized uptake value ratios (SUVRs) for 18F-flutemetamol and its parent molecule 11C-PIB in 20 of the AD subjects and 20 of the MCI patients. We also determined test-retest variability of 18F-flutemetamol SUVRs in 5 of the AD subjects. Results: Blinded visual assessments of 18F-flutemetamol scans assigned 25 of 27 scans from AD subjects and 1 of 15 scans from the elderly HVs to the raised category, corresponding to a sensitivity of 93.1% and a specificity of 93.3% against the SOT. Correlation coefficients between cortical 18F-flutemetamol SUVRs and 11C-PIB SUVRs ranged from 0.89 to 0.92. Test-retest variabilities of regional SUVRs were 1 to 4%. Interpretation: 18F-Flutemetamol performs similarly to the 11C-PIB parent molecule within the same subjects and provides high test-retest replicability and potentially much wider accessibility for clinical and research use. [less ▲]

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See detail18F-FMT: a reliable PET tracer for in vivo evaluation of dopaminergic dysfunction in Parkinson’s Disease rat model.
Becker, Guillaume ULg; Bahri, Mohamed Ali ULg; Michel, Anne et al

Poster (2015, March 18)

Objectives: Rat models of Parkinson’s disease (PD), such as lesioned rats with 6-hydroxydopamine (6-OHDA), are useful for studying dopamine (DA)-related functions. 6-18F-fluoro-m-tyrosine (6-18F-FMT) is ... [more ▼]

Objectives: Rat models of Parkinson’s disease (PD), such as lesioned rats with 6-hydroxydopamine (6-OHDA), are useful for studying dopamine (DA)-related functions. 6-18F-fluoro-m-tyrosine (6-18F-FMT) is an effective PET tracer to evaluate of DA terminals integrity and L-aromatic amino acid decarboxylase (AAAD) metabolic pathway. However, there are currently no available quantitative PET studies using 18F-FMT in 6-OHDA lesioned rats. In this context, we investigated the feasibility of in vivo PET study using 18F-FMT on 6-OHDA PD’s model. Methods: 10 µg of 6-OHDA were injected into the right medial forebrain bundle (MFB) of male Sprague-Dawley rats (n=8). As control, sham-treated rats (n=8) were injected with vehicle only but otherwise treated identically. Striatal DA presynaptic activity was assessed by dynamic 18F-FMT-PET. Structural T2-weighted brain images were acquired on a 9.4T MRI and were used for co-registration. After normalization on a MRI template, kinetic analysis was performed by “Patlak Reference” model, using PMOD software. Results: Striatal accumulation of 18F-FMT was observed in rats pretreated with benserazide, a peripheral AAAD inhibitor. As consequence of the 6-OHDA-lesion, significant decrease of 18F-FMT accumulation was recorded in the striatum ipsilateral to the lesion. Lesioned rats had dramatically reduced uptake constant Ki in the ipsilateral striatum compared to the contralateral striatum (p<0.001) and to the ipsilateral striatum of sham-treated rats (p<0.005). The Ki ratio (Ipsi./Contra.) was equivalent to 94% in the sham group and dropped to 41% in the lesioned group. Conclusions: 18F-FMT PET enables us to quantify loss of DA presynaptic function in unilaterally 6-OHDA lesioned rats. These results encourage us to pursue further investigations in a longitudinal way and to monitor the progression of the dopaminergic dysfunction in more moderate and gradual preclinical PD models. [less ▲]

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See detail18F-FPRGD2 PET/CT imaging of integrin αvβ3 in renal carcinomas: Correlation with histopathology
WITHOFS, Nadia ULg; SIGNOLLE, NICOLAS; SOMJA, Joan ULg et al

in Journal of Nuclear Medicine (The) (2015)

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See detail18F-MPPF Pharmacokinetics in rat hippocampus imaged with MicroPet.
Rubin, D. J.; Way, B.; Lacan, G. et al

in Journal of Nuclear Medicine : Official Publication, Society of Nuclear Medicine (2002), 43(S1), 209

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See detail18F-substituted aromatic aldehydes, key intermediates for nca radiosyntheses.
Lemaire, Christian ULg; Guillaume, M.; Plenevaux, Alain ULg et al

in Journal of Labelled Compounds & Radiopharmaceuticals (1991), 30

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See detail18F-tyrosine PET in Neurooncology : an alternative to 11C-methionine.
KASCHTEN; LEMAIRE, C.; LUXEN, A. et al

in Journal of Nuclear Medicine (The) (2004), 45(SUPPL), 264

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See detail[18F]fallypride binding in the mouse brain: test-retest and effects of registration
Bahri, Mohamed Ali ULg; Geuzaine, Annabelle ULg; Warnock, Geoffrey ULg et al

Conference (2011, January 17)

The quantification of in vivo receptor kinetics with PET tracer experiments is an intricate and challenging problem especially for small animals such as rats and mice. A test-retest scan is usually set up ... [more ▼]

The quantification of in vivo receptor kinetics with PET tracer experiments is an intricate and challenging problem especially for small animals such as rats and mice. A test-retest scan is usually set up in order to confirm an observed experimental effect or to examine the reliability of the experiment design. Inadequate processing of the image data may also mask small effects. The purpose of this study was to investigate the effect of image registration on [18F]fallypride binding potentials calculated from PET mouse test-retest data. Sub-optimal registration affected the quantification of in vivo receptor kinetics with [18F]fallypride. The absence of anatomical information in the [18F]fallypride image and the lack of a homogeneous tracer distribution, even during the earlier minutes of the scan, lead to erroneous automatic registration. A FDG scan after each [18F]fallypride test could improve registration as FDG provides a more homogeneous brain image. Variability in the data could also result from stress induced by anaesthesia or the experimental environment. [less ▲]

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See detail[18F]FMT: a reliable PET tracer for in vivo evaluation of dopaminergic dysfunction in Parkinson’s Disease rat model.
Seret, Alain ULg; Becker, Guillaume ULg; Bahri, Mohamed Ali ULg et al

Poster (2015, May 09)

Background: Rat models of Parkinson’s disease (PD), such as lesioned rats with 6-hydroxydopamine (6-OHDA), are useful for studying dopamine (DA)-related functions. 6-[18F]fluoro-m-tyrosine (6-[18F]FMT) is ... [more ▼]

Background: Rat models of Parkinson’s disease (PD), such as lesioned rats with 6-hydroxydopamine (6-OHDA), are useful for studying dopamine (DA)-related functions. 6-[18F]fluoro-m-tyrosine (6-[18F]FMT) is an effective PET tracer to evaluate of DA terminals integrity and L-aromatic amino acid decarboxylase (AAAD) metabolic pathway. However, there are currently no available quantitative PET studies using [18F]FMT in 6-OHDA lesioned rats. In this context, we investigated the feasibility of in vivo PET study using [18F]FMT on 6-OHDA PD’s model. Methods: 10 µg of 6-OHDA were injected into the right medial forebrain bundle (MFB) of male Sprague-Dawley rats (n=8). As control, sham-treated rats (n=8) were injected with vehicle only but otherwise treated identically. Striatal DA presynaptic activity was assessed by dynamic [18F]FMT PET, 30 min after benserazide pretreatment. Structural T2-weighted brain images were acquired on a 9.4T MRI and were used for co-registration. After normalization on a MRI template, kinetic analysis was performed by “Patlak Reference” model, using PMOD software. Results: Striatal accumulation of [18F]FMT was observed in rats pretreated with benserazide, a peripheral AAAD inhibitor. As consequence of the 6-OHDA-lesion, significant decrease of [18F]FMT accumulation was recorded in the striatum ipsilateral to the lesion. Lesioned rats had dramatically reduced uptake constant Ki in the ipsilateral striatum compared to the contralateral striatum (p<0.001) and to the ipsilateral striatum of sham-treated rats (p<0.005). The Ki ratio (Ipsi./Contra.) was equivalent to 94% in the sham group and dropped to 41% in the lesioned group. Conclusions: [18F]FMT PET enables us to quantify loss of DA presynaptic function in unilaterally 6-OHDA lesioned rats. These results encourage us to pursue further investigations in a longitudinal way and to monitor the progression of the dopaminergic dysfunction in more moderate and gradual preclinical PD models. [less ▲]

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See detail[18F]FPRGD2 PET/CT imaging of integrin αvβ3 levels in patients with locally advanced rectal carcinoma
WITHOFS, Nadia ULg; Martinive, Philippe ULg; VANDERICK, Jean ULg et al

in European journal of nuclear medicine and molecular imaging (2016)

PURPOSE: Our primary objective was to determine if [18F]FPRGD2 PET/CT performed at baseline and/or after chemoradiotherapy (CRT) could predict tumour regression grade (TRG) in locally advanced rectal ... [more ▼]

PURPOSE: Our primary objective was to determine if [18F]FPRGD2 PET/CT performed at baseline and/or after chemoradiotherapy (CRT) could predict tumour regression grade (TRG) in locally advanced rectal cancer (LARC). Secondary objectives were to compare baseline [18F]FPRGD2 and [18F]FDG uptake, to evaluate the correlation between posttreatment [18F]FPRGD2 uptake and tumour microvessel density (MVD) and to determine if [18F]FPRGD2 and FDG PET/CT could predict disease-free survival. METHODS: Baseline [18F]FPRGD2 and FDG PET/CT were performed in 32 consecutive patients (23 men, 9 women; mean age 63 +/- 8 years) with LARC before starting any therapy. A posttreatment [18F]FPRGD2 PET/CT scan was performed in 24 patients after the end of CRT (median interval 7 weeks, range 3 - 15 weeks) and before surgery (median interval 4 days, range 1 - 15 days). RESULTS: All LARC showed uptake of both [18F]FPRGD2 (SUVmax 5.4 +/- 1.5, range 2.7 - 9) and FDG (SUVmax 16.5 +/- 8, range 7.1 - 36.5). There was a moderate positive correlation between [18F]FPRGD2 and FDG SUVmax (Pearson's r = 0.49, p = 0.0026). There was a moderate negative correlation between baseline [18F]FPRGD2 SUVmax and the TRG (Spearman's r = -0.37, p = 0.037), and a [18F]FPRGD2 SUVmax of >5.6 identified all patients with a complete response (TRG 0; AUC 0.84, 95 % CI 0.68 - 1, p = 0.029). In the 24 patients who underwent a posttreatment [18F]FPRGD2 PET/CT scan the response index, calculated as [(SUVmax1 - SUVmax2)/SUVmax1] x 100 %, was not associated with TRG. Post-treatment [18F]FPRGD2 uptake was not correlated with tumour MVD. Neither [18F]FPRGD2 nor FDG uptake predicted disease-free survival. CONCLUSION: Baseline [18F]FPRGD2 uptake was correlated with the pathological response in patients with LARC treated with CRT. However, the specificity was too low to consider its clinical routine use. [less ▲]

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See detail[18F]UCB-H AS A BRAIN SV2A RADIOTRACER: A FIRST CLINICAL TRIAL
Bahri, Mohamed Ali ULg; Bastin, Christine ULg; Aerts, Joël ULg et al

Poster (2014, May 27)

[18F]UCB-H is a fluorine-18 radiolabelled PET imaging tracer with a high affinity for the synaptic vesicle protein 2A (SV2A). This protein, involved in vesicle trafficking and widely distributed in the ... [more ▼]

[18F]UCB-H is a fluorine-18 radiolabelled PET imaging tracer with a high affinity for the synaptic vesicle protein 2A (SV2A). This protein, involved in vesicle trafficking and widely distributed in the brain, represents the binding site and the primary mechanism of the antiepileptic drug levetiracetam. Levetiracetam has recently been suggested to reduce synaptic deficits in a mouse Alzheimer’s disease model and to improve cognition in patients with amnestic mild cognitive impairment, suggesting a possible role for this protein in synaptic integrity. The objective of this study was to investigate the cerebral distribution of [18F]UCB-H in healthy human volunteers. Dynamic PET imaging of the head of four healthy volunteers was performed over 100 minutes after injection of 170.4 ± 24.9 MBq of GMP produced [18F]UCB-H. The input function was acquired by arterial blood sampling during the dynamic PET acquisition. Blood data analysis showed a consistent tracer amount in whole blood and plasma indicating a very low degree of binding of the tracer to the red blood cells. Unchanged [18F]UCB-H fraction in plasma follows a bi-exponential behavioral decrease with a starting fraction of 92% of the injected amount of the tracer, measured at 3 min post injection. This fraction decreases to about 50% at 10 min post injection. The [18F]UCB-H PET data revealed a high and rapid uptake in the grey matter structures, matching the known ubiquitous distribution of SV2A in the brain. The kinetics of the tracer in the brain was characterized by an initial high uptake phase followed by rapid washout allowing the standard compartmental modeling (1-tissue compartment, 2-tissue compartment, and Logan graphical analysis). The three models gave consistent results. The two-tissue compartment model fitted the experimental data best and provided a total distribution volume of [18F]UCB-H in the brain greater than 7 mL/cm3 and a specific distribution volume around 3 mL/cm3. Our results indicate that [18F]UCB-H is a new radiotracer for brain SV2A proteins suitable for human studies. Further studies are warranted to assess SV2A modifications in neurological pathologies such as Alzheimer’s disease. [less ▲]

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See detail[18F]UCB-H AS A NEW PET RADIOTRACER FOR SYNAPTIC VESICLE PROTEIN 2A
Bahri, Mohamed Ali ULg; Bastin, Christine ULg; Aerts, Joël ULg et al

Poster (2014, June 06)

Synaptic vesicle protein 2A (SV2A) is widely distributed in the brain and has been demonstrated to be involved in vesicle trafficking. The critical role of SV2A in proper nervous system function is shown ... [more ▼]

Synaptic vesicle protein 2A (SV2A) is widely distributed in the brain and has been demonstrated to be involved in vesicle trafficking. The critical role of SV2A in proper nervous system function is shown, for example, by the fact that it is a binding site and the primary mechanism of levetiracetam. Levetiracetam is an antiepileptic drug which has recently been suggested to reduce synaptic deficits in a mouse model for Alzheimer’s disease and to improve cognition in patients with amnestic mild cognitive impairment. We here aimed to investigate the cerebral distribution of [18F]UCB-H, a fluorine-18 radiolabelled PET imaging tracer, which has a high affinity with the SV2A. [18F]UCB-H was radiosynthesized under GMP conditions. Dynamic PET data of the head of four healthy volunteers were acquired over 100 minutes after injection of 170.4 ± 24.9 MBq of [18F]UCB-H. The arterial input function was obtained by blood sampling during the dynamic PET acquisition. The analysis of the blood data reveled a consistent amount of [18F]UCB-H in whole blood and plasma which indicates a very low degree of binding of the tracer to the red blood cells. The unchanged fraction of [18F]UCB-H in plasma showed a bi-exponential behavioral decrease with a starting fraction of 92% of the injected amount of the tracer, measured at 3 min post injection. This fraction decreased to about 50% at 10 min post injection. The [18F]UCB-H PET data showed a high and rapid uptake in the grey matter structures, matching the known ubiquitous distribution of the SV2A in the brain. The kinetics of the tracer in the brain was characterized by an initial high uptake phase followed by rapid washout allowing the standard compartmental modeling (1-tissue compartment, 2-tissue compartment, and Logan graphical analysis). The three models gave consistent results. The two-tissue compartment model fitted the experimental data best and provided a total distribution volume of the [18F]UCB-H in the brain greater than 7 mL/cm3 and a specific distribution volume around 3 mL/cm3. Our results suggest that [18F]UCB-H is a good candidate as radiotracer for brain SV2A proteins and could be used for human studies. In the future, SV2A modifications might be assessed in neurological pathologies such as Alzheimer’s disease. [less ▲]

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See detail[18F]UCB-H as a new PET radiotracer for Synaptic vesicle protein 2A: A first clinical trial
Bahri, Mohamed Ali ULg; Stifkens, Mathieu; Bastin, Christine ULg et al

Poster (2015, January 27)

SV2A is widely distributed in the brain and has been demonstrated to be involved in vesicle trafficking. The critical role of SV2A in proper nervous system function is shown, e.g., by the fact that it is ... [more ▼]

SV2A is widely distributed in the brain and has been demonstrated to be involved in vesicle trafficking. The critical role of SV2A in proper nervous system function is shown, e.g., by the fact that it is a binding site and the primary mechanism of levetiracetam. Levetiracetam is an antiepileptic drug which has recently been suggested to reduce synaptic deficits in a mouse model for Alzheimer’s disease. We here aimed to investigate the cerebral distribution of [18F]UCB-H, which has a high affinity with the SV2A. Dynamic PET data of the head of 4 healthy volunteers were acquired over 100 minutes after injection of 170.4 ± 24.9 MBq of GMP produced [18F]UCB-H. The arterial input function (IF) was obtained by blood sampling. The IF was also derived from the dynamic data using the correlation coefficient method. Blood data revealed a consistent amount of [18F]UCB-H in whole blood and plasma indicating a very low degree of binding of the tracer to the red blood cells. The image-derived arterial IFs were showed to be very similar to the measured ones with a peak-ratio around 0.91 and an area-under-curve ratio about 0.98. The [18F]UCB-H PET data showed a high and rapid uptake in the grey matter structures, matching the known ubiquitous distribution of the SV2A in the brain. The kinetics of the tracer in the brain was characterized by an initial high uptake phase followed by rapid washout allowing the standard compartmental modeling (1-tissue, 2-tissue, and Logan Plot). The three models gave similar results with both the measured and image-derived IFs. The total distribution volume of the tracer in the brain was greater than 7 mL/cm3. Our results suggest that [18F]UCB-H is a good candidate as radiotracer for brain SV2A proteins and could be used for human studies. Image-derived IF showed to be useful for quantitative studies without the need to the arterial blood sampling. SV2A modifications may consequently be assessed in neurological pathologies such as Alzheimer’s disease. [less ▲]

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See detail[18F]UCB-H as a new PET radiotracer for Synaptic vesicle protein 2A: A first clinical trial.
Bahri, Mohamed Ali ULg; Stifkens, M; Bastin, Christine ULg et al

in Tijdschrift voor Nucleaire Geneeskunde (2015, May 09), 37(3), 1457-1458

The synaptic vesicle protein 2A (SV2A) is widely distributed in the brain and has been demonstrated to be involved in vesicle trafficking. The critical role of SV2A in proper nervous system function is ... [more ▼]

The synaptic vesicle protein 2A (SV2A) is widely distributed in the brain and has been demonstrated to be involved in vesicle trafficking. The critical role of SV2A in proper nervous system function is shown, e.g., by the fact that it is a binding site and the primary mechanism of the antiepileptic drug levetiracetam. This drug has recently been suggested to reduce synaptic deficits in a mouse model for Alzheimer’s disease. We here aimed to investigate the cerebral distribution of [18F]UCB-H, which has a high affinity with the SV2A. Dynamic PET data of the head of 4 healthy volunteers were acquired over 100 minutes after injection of 170.4 ± 24.9 MBq of GMP produced [18F]UCB-H. The arterial input function (IF) was obtained by blood sampling but also derived from the dynamic data using the correlation coefficient method. Blood data revealed a consistent amount of [18F]UCB-H in whole blood and plasma indicating a very low degree of binding of the tracer to the red blood cells. The unchanged fraction of [18F]UCB-H in plasma showed a bi-exponential behavioral decrease with a starting fraction of 92% of the injected amount of the tracer, measured at 3 min post injection. This fraction decreased to about 50% at 10 min post injection. The image-derived arterial IFs showed to be very similar to the measured ones with a peak-ratio around 0.91 and an area-under-curve ratio about 0.98. The PET images showed a high and rapid uptake of [18F]UCB-H in the grey matter structures, matching the known ubiquitous distribution of the SV2A in the brain. The kinetics of the tracer in the brain was characterized by an initial high uptake phase followed by rapid washout. For the three standard compartmental models (1-tissue, 2-tissue, and Logan Plot), similar results were obtained with both the measured and image-derived IFs. Nevertheless the two-tissue compartment model fitted the experimental data best and provided a total distribution volume of the [18F]UCB-H in the brain greater than 7 mL/cm3 and a specific distribution volume around 3 mL/cm3. Our results suggest that [18F]UCB-H is a good candidate as radiotracer for brain SV2A proteins and could be used for human studies (dosimetry has already been reported elsewhere). Image-derived IF showed to be useful for quantitative studies without the need to the arterial blood sampling. This new tracer could help to assess SV2A modifications in neurological pathologies such as Alzheimer’s disease. [less ▲]

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See detail18fdg-Pet for the Assessment of Primary Head and Neck Tumors: Clinical, Computed Tomography, and Histopathological Correlation in 38 Patients
Paulus, Patrick; Sambon, A.; Vivegnis, Danielle et al

in Laryngoscope (1998), 108(10), 1578-83

OBJECTIVES: To evaluate the clinical usefulness of FDG-PET (fluoro-2-deoxy-glucose-positron emission tomography) in the detection of lymph node involvement and recurrences in patients with head and neck ... [more ▼]

OBJECTIVES: To evaluate the clinical usefulness of FDG-PET (fluoro-2-deoxy-glucose-positron emission tomography) in the detection of lymph node involvement and recurrences in patients with head and neck cancer. STUDY DESIGN: Retrospective review of 38 patients with biopsy-proven head and neck cancers who underwent clinical, computed tomography (CT), and FDG-PET examinations. Twenty-five patients were studied prior to therapy and 13 patients were evaluated for disease recurrence. METHODS: All patients were operated and clinical data, CT, and FDG-PET results were correlated with histopathological findings. RESULTS: All primary tumors in 25 patients were detected, with the exception of one small superficial localization of the epiglottis. Histopathological examination showed lymph node involvement in 10 patients; PET detected lymph node involvement in five. FDG-PET found one case of nodal disease not identified by clinical and CT examination. With so few cases, this could be anecdotal. Five false-negative results (microscopic lymph node involvement) and two false positives were noted. Twelve of 13 patients with recurrent disease were correctly identified with FDG-PET. FDG-PET was the only imaging technique to identify local recurrence in two patients and lymph node involvement in two others. One false-positive result occurred in a patient with a foreign body granuloma. CONCLUSIONS: FDG-PET is a useful diagnostic modality for the detection of recurrent tumors and, in selected cases, precise lymph node involvement. The best way to further investigate the utility of clinical FDG-PET is in the follow-up of treated patients. [less ▲]

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