Jan Versijpt | Vrije Universiteit Brussel (original) (raw)
Papers by Jan Versijpt
Nuclear medicine communications, 2001
Inflammatory mechanisms contribute to the pathophysiology of senile dementia of the Alzheimer typ... more Inflammatory mechanisms contribute to the pathophysiology of senile dementia of the Alzheimer type (sDAT). Previous studies have shown that 57Co single photon emission computed tomography (SPECT) is able to visualize inflammatory lesions, probably by means of the final common pathway of Ca2+ homeostasis disturbance in both neuronal degeneration and inflammation. The aims of this study were: (1) to detect 57Co SPECT changes in sDAT patients; (2) to correlate these findings with those of conventional neuroimaging techniques and neuropsychological testing (NPT); and (3) to compare 57Co SPECT findings in sDAT patients with those in other types of dementia. Six patients suffering from probable sDAT were included and compared with four patients suffering from other types of dementia. All patients had a magnetic resonance imaging (MRI) scan, NPT, 57Co and 99mTc-ethyl cysteinate dimer (ECD) SPECT scan. Perfusion SPECT images were semiquantitatively evaluated by comparison with an age-matche...
European Neurology, 2003
Objectives: Inflammation contributes to degeneration in Alzheimer's disease (AD), not simply as a... more Objectives: Inflammation contributes to degeneration in Alzheimer's disease (AD), not simply as a secondary phenomenon, but primarily as a significant source of pathology. [ 123 I]iodo-PK11195 is a single photon emission computed tomography (SPECT) ligand for the peripheral benzodiazepine receptor, the latter being expressed on microglia (brain resident macrophages) and upregulated under inflammatory circumstances. The objectives were to assess AD inflammation by detecting [ 123 I]iodo-PK11195 uptake changes and investigate how uptake values relate with perfusion SPECT and neuropsychological findings. Methods: Ten AD and 9 control subjects were included. [ 123 I]iodo-PK11195 SPECT images were realigned into stereotactic space where binding indices, normalized on cerebellar uptake, were calculated. Results: The mean [ 123 I]iodo-PK11195 uptake was increased in AD patients compared with controls in nearly all neocortical regions; however, statistical significance was only reached in the frontal and right mesotemporal regions. Significant correlations were found between regional increased [ 123 I]iodo-PK11195 uptake and cognitive deficits. Conclusions: [ 123 I]iodo-PK11195 is a cellular disease activity marker and allows in vivo assessment of microglial inflammation in AD.
![Research paper thumbnail of Accurate differentiation of parkinsonism and essential tremor using visual assessment of [123I]-FP-CIT SPECT imaging: The [123I]-FP-CIT study group](https://attachments.academia-assets.com/53463401/thumbnails/1.jpg)
](Movement Disorders, 2000
OBJECTIVE: To evaluate whether visual assessment of [ 123 I]-FP-CIT (DaTSCAN™, Nycomed Amersham, ... more OBJECTIVE: To evaluate whether visual assessment of [ 123 I]-FP-CIT (DaTSCAN™, Nycomed Amersham, plc) single photon emission computerized tomography (SPECT) images can differentiate between parkinsonism and essential tremor (ET).
Neurobiology of Aging, 2000
Neurobiology of Aging, 2003
Serotonin (5-HT) and more specifically the 5-HT 2A receptor is involved in cognitive and non-cogn... more Serotonin (5-HT) and more specifically the 5-HT 2A receptor is involved in cognitive and non-cognitive behavior and plays an important role in Alzheimer's disease (AD). The objective was to assess the 5-HT 2A binding potential (BP) in healthy volunteers and AD with SPECT and 123 I-5-I-R91150, a selective radio-iodinated 5-HT 2A receptor antagonist. Twenty-six controls and nine AD patients were included. A semiquantitive analysis with normalization on cerebellar uptake provided estimates of BP for 26 cortical regions of interest. An age-related decline of neocortical BP was found (11.6% per decade). Compared to age-matched controls, a generally decreased neocortical BP in AD was found with a significant regional reduction in the orbitofrontal, prefrontal, lateral frontal, cingulate, sensorimotor, parietal inferior, and occipital region. These results are in line with previous postmortem, in vitro, and PET findings. The age-related decline highlights the necessity for matched advanced age study samples. The fact that the 5-HT 2A receptor is differentially affected in AD patients has implications for both the etiological basis and therapeutic management of AD.
![Research paper thumbnail of Preliminary evaluation of the amyloid PET Radioligand [18F]MK-3328 in Alzheimer's Disease patients](https://attachments.academia-assets.com/43642219/thumbnails/1.jpg)
](Alzheimer's & Dementia, 2011
oligomers did not correlate with Ab1-42, P-Tau or T-Tau in the AD or control group. An optimal cu... more oligomers did not correlate with Ab1-42, P-Tau or T-Tau in the AD or control group. An optimal cut-point of 0.8 pg/mL distinguished AD patients from controls with a sensitivity of 74% and a specificity of 85%. Conclusions: Our data showed that patients with diagnosed AD have elevated levels of Ab oligomers, indicating that Ab oligomers could be used as a biomarker for AD.
European Journal of Nuclear Medicine
The highest concentrations of the peripheral benzodiazepine receptor (PBR) are found in the kidne... more The highest concentrations of the peripheral benzodiazepine receptor (PBR) are found in the kidneys and heart. In addition, the PBR has been reported to reflect neuro-inflammatory damage by co-localisation with activated microglia. PK 11195 is a high-affinity ligand for the PBR. The aim of this study was to investigate in humans the biodistribution and dosimetry of [123I]iodoPK 11195, a potential single-photon emission tomography tracer for the PBR. Five healthy volunteers were injected with 112 MBq of [123I]iodo-PK 11195. Sequential whole-body scans were performed up to 72 h post injection. Multiple blood samples were taken, and urine was collected to measure the fraction voided by the renal system. Decay-corrected regions of interest of the whole-body images were analysed, and geometric mean count rates were used to determine organ activity. Organ absorbed doses and effective dose were calculated using the MIRD method. [123I]iodo-PK 11195 was rapidly cleared from the blood, mainly...
![Research paper thumbnail of In vivo evaluation in mice and metabolism in blood of human volunteers of [123I]iodo-PK11195: a possible single-photon emission tomography tracer for visualization of inflammation](https://attachments.academia-assets.com/42590904/thumbnails/1.jpg)
](European Journal of Nuclear Medicine
We report the in vivo evaluation (biodistribution, displacement and metabolization in blood, brai... more We report the in vivo evaluation (biodistribution, displacement and metabolization in blood, brain and heart) in mice and the metabolism in blood of human volunteers of iodine-123 labelled 1-(2-iodophenyl)-N-methyl-N-(1-methyl-propyl)-3-isoquinoline carboxamide ([123I]iodo-PK11195), a potential radioligand for visualization of inflammation in humans by single-photon emission tomography. In three series of 18 white mice (NMRI, 20-25 g), the concentration of radioactivity was measured during 48 h. Blood samples were taken, organs and intestines were excised, excretion was collected and all tissues were weighed and counted for radioactivity. The tissue uptake of radioactivity was measured as % of the injected activity/g of tissue. The excretion was expressed as % of the injected activity. Selective tissue uptake was investigated by pretreatment of another three series of 18 mice with cold PK11195 (1 mg/kg body weight). There was an inflow of [123I]iodo-PK11195 in the brain and among pe...
Journal of Nuclear Medicine
The purpose of this study was to assess the value of 99mTc-pertechnetate scanning in the diagnosi... more The purpose of this study was to assess the value of 99mTc-pertechnetate scanning in the diagnosis of gastric banding leaks. Three patients with morbid obesity received laparoscopic adjustable silicone gastric banding (ASGB), but no significant weight reduction was obtained. To exclude band leakage as the cause, four scintigraphic procedures were performed, consisting of imaging the upper abdomen 30 min and 3 h after injection of 3 mL (111 MBq) pertechnetate solution into the ASGB reservoir. In one patient, the integrity of the ASGB device was first assessed radiologically after injection of a water-soluble contrast agent into the ASGB reservoir. In two normally functioning ASGB devices, radiotracer was observed within the device on both early and late images. In two patients with a surgically proven small leak in the reservoir or the connecting tube, late images showed little tracer in the reservoir and the connecting tube. However, intense tracer accumulation was observed in the s...
Journal of Nuclear Medicine
Journal of Nuclear Medicine
Left-sided vagus nerve stimulation (VNS) is an efficacious treatment for patients with refractory... more Left-sided vagus nerve stimulation (VNS) is an efficacious treatment for patients with refractory epilepsy. Previous studies have implicated thalamic and mesial temporal involvement in acute stimulation. In this study, acute and chronic effects of VNS in patients with refractory complex partial seizures with or without secondary generalization (CPS +/- SG) were evaluated with respect to the prestimulus condition and long-term follow-up. Twenty-three patients (12 females, 11 males; mean age, 32.4 +/- 10.6 y; mean CPS +/- SG duration, 21.0 +/- 11.7 y) were prospectively included. All patients were considered unsuitable candidates for resective surgery because of nonlocalizing findings in the presurgical evaluation. All underwent a split-dose (99m)Tc-ethyl cysteinate dimer activation study before and immediately after their initial stimulation (0.25 or 0.5 mA, 30 Hz) on a high-resolution triple-head gamma camera. Ten patients also underwent a SPECT activation study 5.7 +/- 1.6 mo after...
Nuclear Medicine Communications
Performance on the Verbal Fluency Test, as a measure of the ability of initiating processes, is r... more Performance on the Verbal Fluency Test, as a measure of the ability of initiating processes, is reduced in depressed suicidal patients. The hampered results in this prefrontal executive task parallel the reduction in prefrontal blood perfusion and metabolism in depressed subjects. A neuropsychological activation study with the verbal fluency paradigm could evaluate a possible blunted increase in perfusion in the prefrontal cortex in depressed suicidal patients. Twenty clinically depressed patients who had recently attempted suicide and 20 healthy volunteers were included in a single photon emission computed tomography (SPECT) split-dose activation study following a verbal fluency paradigm. Statistical parametric mapping was used to determine voxelwise significant changes. Differences in regional cortical activation between the letter fluency and category fluency tasks in attempted suicide patients were found. These patients showed a blunted increase in perfusion in the prefrontal co...
2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310), 2002
The accurate quantification of emission computed tomography data (PET-SPECT) is limited by partia... more The accurate quantification of emission computed tomography data (PET-SPECT) is limited by partial volume effects (PVE). The influence of these effects on quantification depends on the size of the structure in relation to the spatial resolution and may lead to an over- and/or underestimation of the true tracer concentration. This particularly holds for brain perfusion SPECT imaging, where white matter
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2002
The technique of anatomic standardization and comparison with normal templates is increasingly us... more The technique of anatomic standardization and comparison with normal templates is increasingly used in clinical brain SPECT practice and allows automated, operator-independent volume-of-interest (VOI) or voxel-based analysis of whole-brain data. In 2 distinct clinical populations with severe traumatic brain injury and cognitive impairment, this study compared 3 widely available approaches that use normal templates to evaluate SPECT brain perfusion deficits. In total, 74 subjects were studied. These included 14 patients with severe, traumatic brain injury (group 1; 10 males, 4 females; mean age +/- SD, 27.6 +/- 8.2 y) and 15 patients with cognitive impairment (group 2; 7 males, 8 females; mean age, 75.8 +/- 8.6 y). These data were compared with those from, respectively, 25 and 20 age- and sex-adjusted healthy volunteers. All data were analyzed in 4 ways. Three semiquantitative statistical algorithms were used: statistical parametric mapping (SPM) using SPM99, brain registration and a...
Nuclear medicine communications, 2001
This phase I pilot study reports on (1) the safety and feasibility of 99Tc(m)-HL91, an amine oxim... more This phase I pilot study reports on (1) the safety and feasibility of 99Tc(m)-HL91, an amine oxime core radioligand that has shown oxygen dependent binding, and imaging; and (2) its usefulness for the visualization of local tumour recurrence of a biopsy proven squamous cell carcinoma of the head and neck (SCCHN) as compared to spiral computed tomogaphy (CT) and biopsy. Nine men (mean age 33 years, range 34-74 years) were prospectively included. For safety measurements, vital signs were recorded and serum chemical analysis carried out, with a complete blood cell count and urine analysis, and an ECG was performed prior to injection of 99Tc(m)-HL91 and repeated during the investigation. Single photon emission computed tomography (SPECT) scans of the head and neck, and of a standard, were performed at 2 h and 4 h post-injection of 740 MBq 99Tc(m)-HL91. Tumour-to-normal tissue background (T/N) ratios and percentage uptake were measured for all 99Tc(m)-HL91 scans. Spiral CT scans were obt...
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2001
Intra- or intersubject registration of anatomically poorly defined SPECT data, such as in neurore... more Intra- or intersubject registration of anatomically poorly defined SPECT data, such as in neuroreceptor imaging, is important for longitudinal or group analysis. However, accurate registration is difficult with only emission CT (ECT) data. We investigated fully automated registration using transmission CT (TCT) data as an intermediary image set. The accuracy of TCT registration was compared to that of ECT registration for four types of data: gray-matter distribution (with [99mTc]ethylcysteinate dimer (ECD)), neocortical distribution (with [123I]R91150, a highly specific 5-HT2a receptor ligand), and striatal distribution of the D2-receptor ligand (with [123I]iodobenzamide (IBZM)) and the dopamine transporter ligand (with [123I]2beta-carbomethoxy-3beta-(4-fluorophenyl)tropane (CIT)). In total, 10 datasets of the various study types were used, all collected on a Toshiba GCA9300 gamma camera with super-high-resolution fanbeam collimators and 3 x 370 MBq of 153Gd transmission sources (4-...
![Research paper thumbnail of Semiquantification of the peripheral-type benzodiazepine ligand [11C]PK11195 in normal human brain and application in multiple sclerosis patients](https://attachments.academia-assets.com/42590894/thumbnails/1.jpg)
](Acta neurologica Belgica, 2002
Objectives : [ 11 C]PK11195 is a peripheral-benzodiazepine-receptor radioligand used for detectio... more Objectives : [ 11 C]PK11195 is a peripheral-benzodiazepine-receptor radioligand used for detection of microglial inflammation. Normal uptake by means of semiquantification was measured in order to establish reference data. The applicability of this semiquantitative approach was tested in three multiple sclerosis patients.
International journal of geriatric psychiatry, Jan 3, 2014
Iodine-123 metaiodobenzylguanidine (MIBG) cardiac scintigraphy has shown the potential to discrim... more Iodine-123 metaiodobenzylguanidine (MIBG) cardiac scintigraphy has shown the potential to discriminate dementia with Lewy bodies (DLB) from Alzheimer's disease (AD). However, these studies did not reflect clinical practice, as patients with ischemic heart disease, heart failure, diabetes mellitus, arterial hypertension, and hyperlipidemia and patients treated with antidepressants like trazodone were excluded. This study aimed to evaluate the use of MIBG cardiac scintigraphy to diagnose DLB in clinical practice. Moreover, the potential diagnostic value of MIBG cardiac scintigraphy in patients with clinically ambiguous dementia diagnosis (DLB versus AD) was tested. Eighty-five patients with a possible clinical diagnosis of DLB entered the study. MIBG uptake was determined by calculating the heart-to-mediastinum-uptake ratio (H/M). The average H/M ratio was 1.42 ± 0.35. The number of core features for DLB and the H/M ratio were negatively correlated (p = 0.001; r = -0.360). With an...
Nuclear medicine communications, 2001
Inflammatory mechanisms contribute to the pathophysiology of senile dementia of the Alzheimer typ... more Inflammatory mechanisms contribute to the pathophysiology of senile dementia of the Alzheimer type (sDAT). Previous studies have shown that 57Co single photon emission computed tomography (SPECT) is able to visualize inflammatory lesions, probably by means of the final common pathway of Ca2+ homeostasis disturbance in both neuronal degeneration and inflammation. The aims of this study were: (1) to detect 57Co SPECT changes in sDAT patients; (2) to correlate these findings with those of conventional neuroimaging techniques and neuropsychological testing (NPT); and (3) to compare 57Co SPECT findings in sDAT patients with those in other types of dementia. Six patients suffering from probable sDAT were included and compared with four patients suffering from other types of dementia. All patients had a magnetic resonance imaging (MRI) scan, NPT, 57Co and 99mTc-ethyl cysteinate dimer (ECD) SPECT scan. Perfusion SPECT images were semiquantitatively evaluated by comparison with an age-matche...
European Neurology, 2003
Objectives: Inflammation contributes to degeneration in Alzheimer's disease (AD), not simply as a... more Objectives: Inflammation contributes to degeneration in Alzheimer's disease (AD), not simply as a secondary phenomenon, but primarily as a significant source of pathology. [ 123 I]iodo-PK11195 is a single photon emission computed tomography (SPECT) ligand for the peripheral benzodiazepine receptor, the latter being expressed on microglia (brain resident macrophages) and upregulated under inflammatory circumstances. The objectives were to assess AD inflammation by detecting [ 123 I]iodo-PK11195 uptake changes and investigate how uptake values relate with perfusion SPECT and neuropsychological findings. Methods: Ten AD and 9 control subjects were included. [ 123 I]iodo-PK11195 SPECT images were realigned into stereotactic space where binding indices, normalized on cerebellar uptake, were calculated. Results: The mean [ 123 I]iodo-PK11195 uptake was increased in AD patients compared with controls in nearly all neocortical regions; however, statistical significance was only reached in the frontal and right mesotemporal regions. Significant correlations were found between regional increased [ 123 I]iodo-PK11195 uptake and cognitive deficits. Conclusions: [ 123 I]iodo-PK11195 is a cellular disease activity marker and allows in vivo assessment of microglial inflammation in AD.
Movement Disorders, 2000
OBJECTIVE: To evaluate whether visual assessment of [ 123 I]-FP-CIT (DaTSCAN™, Nycomed Amersham, ... more OBJECTIVE: To evaluate whether visual assessment of [ 123 I]-FP-CIT (DaTSCAN™, Nycomed Amersham, plc) single photon emission computerized tomography (SPECT) images can differentiate between parkinsonism and essential tremor (ET).
Neurobiology of Aging, 2000
Neurobiology of Aging, 2003
Serotonin (5-HT) and more specifically the 5-HT 2A receptor is involved in cognitive and non-cogn... more Serotonin (5-HT) and more specifically the 5-HT 2A receptor is involved in cognitive and non-cognitive behavior and plays an important role in Alzheimer's disease (AD). The objective was to assess the 5-HT 2A binding potential (BP) in healthy volunteers and AD with SPECT and 123 I-5-I-R91150, a selective radio-iodinated 5-HT 2A receptor antagonist. Twenty-six controls and nine AD patients were included. A semiquantitive analysis with normalization on cerebellar uptake provided estimates of BP for 26 cortical regions of interest. An age-related decline of neocortical BP was found (11.6% per decade). Compared to age-matched controls, a generally decreased neocortical BP in AD was found with a significant regional reduction in the orbitofrontal, prefrontal, lateral frontal, cingulate, sensorimotor, parietal inferior, and occipital region. These results are in line with previous postmortem, in vitro, and PET findings. The age-related decline highlights the necessity for matched advanced age study samples. The fact that the 5-HT 2A receptor is differentially affected in AD patients has implications for both the etiological basis and therapeutic management of AD.
Alzheimer's & Dementia, 2011
oligomers did not correlate with Ab1-42, P-Tau or T-Tau in the AD or control group. An optimal cu... more oligomers did not correlate with Ab1-42, P-Tau or T-Tau in the AD or control group. An optimal cut-point of 0.8 pg/mL distinguished AD patients from controls with a sensitivity of 74% and a specificity of 85%. Conclusions: Our data showed that patients with diagnosed AD have elevated levels of Ab oligomers, indicating that Ab oligomers could be used as a biomarker for AD.
European Journal of Nuclear Medicine
The highest concentrations of the peripheral benzodiazepine receptor (PBR) are found in the kidne... more The highest concentrations of the peripheral benzodiazepine receptor (PBR) are found in the kidneys and heart. In addition, the PBR has been reported to reflect neuro-inflammatory damage by co-localisation with activated microglia. PK 11195 is a high-affinity ligand for the PBR. The aim of this study was to investigate in humans the biodistribution and dosimetry of [123I]iodoPK 11195, a potential single-photon emission tomography tracer for the PBR. Five healthy volunteers were injected with 112 MBq of [123I]iodo-PK 11195. Sequential whole-body scans were performed up to 72 h post injection. Multiple blood samples were taken, and urine was collected to measure the fraction voided by the renal system. Decay-corrected regions of interest of the whole-body images were analysed, and geometric mean count rates were used to determine organ activity. Organ absorbed doses and effective dose were calculated using the MIRD method. [123I]iodo-PK 11195 was rapidly cleared from the blood, mainly...
European Journal of Nuclear Medicine
We report the in vivo evaluation (biodistribution, displacement and metabolization in blood, brai... more We report the in vivo evaluation (biodistribution, displacement and metabolization in blood, brain and heart) in mice and the metabolism in blood of human volunteers of iodine-123 labelled 1-(2-iodophenyl)-N-methyl-N-(1-methyl-propyl)-3-isoquinoline carboxamide ([123I]iodo-PK11195), a potential radioligand for visualization of inflammation in humans by single-photon emission tomography. In three series of 18 white mice (NMRI, 20-25 g), the concentration of radioactivity was measured during 48 h. Blood samples were taken, organs and intestines were excised, excretion was collected and all tissues were weighed and counted for radioactivity. The tissue uptake of radioactivity was measured as % of the injected activity/g of tissue. The excretion was expressed as % of the injected activity. Selective tissue uptake was investigated by pretreatment of another three series of 18 mice with cold PK11195 (1 mg/kg body weight). There was an inflow of [123I]iodo-PK11195 in the brain and among pe...
Journal of Nuclear Medicine
The purpose of this study was to assess the value of 99mTc-pertechnetate scanning in the diagnosi... more The purpose of this study was to assess the value of 99mTc-pertechnetate scanning in the diagnosis of gastric banding leaks. Three patients with morbid obesity received laparoscopic adjustable silicone gastric banding (ASGB), but no significant weight reduction was obtained. To exclude band leakage as the cause, four scintigraphic procedures were performed, consisting of imaging the upper abdomen 30 min and 3 h after injection of 3 mL (111 MBq) pertechnetate solution into the ASGB reservoir. In one patient, the integrity of the ASGB device was first assessed radiologically after injection of a water-soluble contrast agent into the ASGB reservoir. In two normally functioning ASGB devices, radiotracer was observed within the device on both early and late images. In two patients with a surgically proven small leak in the reservoir or the connecting tube, late images showed little tracer in the reservoir and the connecting tube. However, intense tracer accumulation was observed in the s...
Journal of Nuclear Medicine
Journal of Nuclear Medicine
Left-sided vagus nerve stimulation (VNS) is an efficacious treatment for patients with refractory... more Left-sided vagus nerve stimulation (VNS) is an efficacious treatment for patients with refractory epilepsy. Previous studies have implicated thalamic and mesial temporal involvement in acute stimulation. In this study, acute and chronic effects of VNS in patients with refractory complex partial seizures with or without secondary generalization (CPS +/- SG) were evaluated with respect to the prestimulus condition and long-term follow-up. Twenty-three patients (12 females, 11 males; mean age, 32.4 +/- 10.6 y; mean CPS +/- SG duration, 21.0 +/- 11.7 y) were prospectively included. All patients were considered unsuitable candidates for resective surgery because of nonlocalizing findings in the presurgical evaluation. All underwent a split-dose (99m)Tc-ethyl cysteinate dimer activation study before and immediately after their initial stimulation (0.25 or 0.5 mA, 30 Hz) on a high-resolution triple-head gamma camera. Ten patients also underwent a SPECT activation study 5.7 +/- 1.6 mo after...
Nuclear Medicine Communications
Performance on the Verbal Fluency Test, as a measure of the ability of initiating processes, is r... more Performance on the Verbal Fluency Test, as a measure of the ability of initiating processes, is reduced in depressed suicidal patients. The hampered results in this prefrontal executive task parallel the reduction in prefrontal blood perfusion and metabolism in depressed subjects. A neuropsychological activation study with the verbal fluency paradigm could evaluate a possible blunted increase in perfusion in the prefrontal cortex in depressed suicidal patients. Twenty clinically depressed patients who had recently attempted suicide and 20 healthy volunteers were included in a single photon emission computed tomography (SPECT) split-dose activation study following a verbal fluency paradigm. Statistical parametric mapping was used to determine voxelwise significant changes. Differences in regional cortical activation between the letter fluency and category fluency tasks in attempted suicide patients were found. These patients showed a blunted increase in perfusion in the prefrontal co...
2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310), 2002
The accurate quantification of emission computed tomography data (PET-SPECT) is limited by partia... more The accurate quantification of emission computed tomography data (PET-SPECT) is limited by partial volume effects (PVE). The influence of these effects on quantification depends on the size of the structure in relation to the spatial resolution and may lead to an over- and/or underestimation of the true tracer concentration. This particularly holds for brain perfusion SPECT imaging, where white matter
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2002
The technique of anatomic standardization and comparison with normal templates is increasingly us... more The technique of anatomic standardization and comparison with normal templates is increasingly used in clinical brain SPECT practice and allows automated, operator-independent volume-of-interest (VOI) or voxel-based analysis of whole-brain data. In 2 distinct clinical populations with severe traumatic brain injury and cognitive impairment, this study compared 3 widely available approaches that use normal templates to evaluate SPECT brain perfusion deficits. In total, 74 subjects were studied. These included 14 patients with severe, traumatic brain injury (group 1; 10 males, 4 females; mean age +/- SD, 27.6 +/- 8.2 y) and 15 patients with cognitive impairment (group 2; 7 males, 8 females; mean age, 75.8 +/- 8.6 y). These data were compared with those from, respectively, 25 and 20 age- and sex-adjusted healthy volunteers. All data were analyzed in 4 ways. Three semiquantitative statistical algorithms were used: statistical parametric mapping (SPM) using SPM99, brain registration and a...
Nuclear medicine communications, 2001
This phase I pilot study reports on (1) the safety and feasibility of 99Tc(m)-HL91, an amine oxim... more This phase I pilot study reports on (1) the safety and feasibility of 99Tc(m)-HL91, an amine oxime core radioligand that has shown oxygen dependent binding, and imaging; and (2) its usefulness for the visualization of local tumour recurrence of a biopsy proven squamous cell carcinoma of the head and neck (SCCHN) as compared to spiral computed tomogaphy (CT) and biopsy. Nine men (mean age 33 years, range 34-74 years) were prospectively included. For safety measurements, vital signs were recorded and serum chemical analysis carried out, with a complete blood cell count and urine analysis, and an ECG was performed prior to injection of 99Tc(m)-HL91 and repeated during the investigation. Single photon emission computed tomography (SPECT) scans of the head and neck, and of a standard, were performed at 2 h and 4 h post-injection of 740 MBq 99Tc(m)-HL91. Tumour-to-normal tissue background (T/N) ratios and percentage uptake were measured for all 99Tc(m)-HL91 scans. Spiral CT scans were obt...
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2001
Intra- or intersubject registration of anatomically poorly defined SPECT data, such as in neurore... more Intra- or intersubject registration of anatomically poorly defined SPECT data, such as in neuroreceptor imaging, is important for longitudinal or group analysis. However, accurate registration is difficult with only emission CT (ECT) data. We investigated fully automated registration using transmission CT (TCT) data as an intermediary image set. The accuracy of TCT registration was compared to that of ECT registration for four types of data: gray-matter distribution (with [99mTc]ethylcysteinate dimer (ECD)), neocortical distribution (with [123I]R91150, a highly specific 5-HT2a receptor ligand), and striatal distribution of the D2-receptor ligand (with [123I]iodobenzamide (IBZM)) and the dopamine transporter ligand (with [123I]2beta-carbomethoxy-3beta-(4-fluorophenyl)tropane (CIT)). In total, 10 datasets of the various study types were used, all collected on a Toshiba GCA9300 gamma camera with super-high-resolution fanbeam collimators and 3 x 370 MBq of 153Gd transmission sources (4-...
Acta neurologica Belgica, 2002
Objectives : [ 11 C]PK11195 is a peripheral-benzodiazepine-receptor radioligand used for detectio... more Objectives : [ 11 C]PK11195 is a peripheral-benzodiazepine-receptor radioligand used for detection of microglial inflammation. Normal uptake by means of semiquantification was measured in order to establish reference data. The applicability of this semiquantitative approach was tested in three multiple sclerosis patients.
International journal of geriatric psychiatry, Jan 3, 2014
Iodine-123 metaiodobenzylguanidine (MIBG) cardiac scintigraphy has shown the potential to discrim... more Iodine-123 metaiodobenzylguanidine (MIBG) cardiac scintigraphy has shown the potential to discriminate dementia with Lewy bodies (DLB) from Alzheimer's disease (AD). However, these studies did not reflect clinical practice, as patients with ischemic heart disease, heart failure, diabetes mellitus, arterial hypertension, and hyperlipidemia and patients treated with antidepressants like trazodone were excluded. This study aimed to evaluate the use of MIBG cardiac scintigraphy to diagnose DLB in clinical practice. Moreover, the potential diagnostic value of MIBG cardiac scintigraphy in patients with clinically ambiguous dementia diagnosis (DLB versus AD) was tested. Eighty-five patients with a possible clinical diagnosis of DLB entered the study. MIBG uptake was determined by calculating the heart-to-mediastinum-uptake ratio (H/M). The average H/M ratio was 1.42 ± 0.35. The number of core features for DLB and the H/M ratio were negatively correlated (p = 0.001; r = -0.360). With an...