Elena Prieto - Academia.edu (original) (raw)
Papers by Elena Prieto
A high proportion of patients with Parkinson´s disease (PD) develop dementia. The profile of the ... more A high proportion of patients with Parkinson´s disease (PD) develop dementia. The profile of the cognitive deficits exhibited by these patients is different from the one typical of Alzheimer disease (AD). The brain metabolic dysfunction underlying dementia in AD is well established. In PD with dementia (PDD) some studies with SPECT 1-3 reveal a reduction of cerebral perfusion in parieto-occipital and temporal areas. However, only a few FDG PET studies 4-6 have been undertaken to define more precisely the pattern of brain hypometabolism. Equally, few comparative studies with AD FDG PET studies have been reported 7-8 . The aim of this study is to define the pattern of brain metabolism in AD and PDD and the differences between them.
Physica Medica, 2015
To assess the influence of reconstruction algorithms and parameters on the PET image quality of b... more To assess the influence of reconstruction algorithms and parameters on the PET image quality of brain phantoms in order to optimize reconstruction for clinical PET brain studies in a new generation PET/CT. The 3D Hoffman phantom that simulates (18)F-fluorodeoxyglucose (FDG) distribution was imaged in a Siemens Biograph mCT TrueV PET/CT with Time of Flight (TOF) and Point Spread Function (PSF) modelling. Contrast-to-Noise Ratio (CNR), contrast and noise were studied for different reconstruction models: OSEM, OSEM + TOF, OSEM + PSF and OSEM + PSF + TOF. The 2D multi-compartment Hoffman phantom was filled to simulate 4 different tracers' spatial distribution: FDG, (11)C-flumazenil (FMZ), (11)C-Methionine (MET) and 6-(18)F-fluoro-l-dopa (FDOPA). The best algorithm for each tracer was selected by visual inspection. The maximization of CNR determined the optimal parameters for each reconstruction. In the 3D Hoffman phantom, both noise and contrast increased with increasing number of iterations and decreased with increasing FWHM. OSEM + PSF + TOF reconstruction was generally superior to other reconstruction models. Visual analysis of the 2D Hoffman brain phantom suggested that OSEM + PSF + TOF is the optimum algorithm for tracers with focal uptake, such as MET or FDOPA, and OSEM + TOF for tracers with diffuse cortical uptake (i.e. FDG and FMZ). Optimization of CNR demonstrated that OSEM + TOF reconstruction must be performed with 2 iterations and a filter FWHM of 3 mm, and OSEM + PSF + TOF reconstruction with 4 iterations and 1 mm FWHM filter. Optimization of reconstruction algorithm and parameters has been performed to take particular advantage of the last generation PET scanner, recommending specific settings for different brain PET radiotracers.
European Journal of Nuclear Medicine and Molecular Imaging, 2015
Clinical diagnosis of human prion diseases can be challenging since symptoms are common to other ... more Clinical diagnosis of human prion diseases can be challenging since symptoms are common to other disorders associated with rapidly progressive dementia. In this context, (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) might be a useful complementary tool. The aim of this study was to determine the metabolic pattern in human prion diseases, particularly sporadic Creutzfeldt-Jakob disease (sCJD), the new variant of Creutzfeldt-Jakob disease (vCJD) and fatal familial insomnia (FFI). We retrospectively studied 17 patients with a definitive, probable or possible prion disease who underwent FDG PET in our institution. Of these patients, 12 were diagnosed as sCJD (9 definitive, 2 probable and 1 possible), 1 was diagnosed as definitive vCJD and 4 were diagnosed as definitive FFI. The hypometabolic pattern of each individual and comparisons across the groups of subjects (control subjects, sCJD and FFI) were evaluated using a voxel-based analysis. The sCJD group exhibited a pattern of hypometabolism that affected both subcortical (bilateral caudate, thalamus) and cortical (frontal cortex) structures, while the FFI group only presented a slight hypometabolism in the thalamus. Individual analysis demonstrated a considerable variability of metabolic patterns among patients, with the thalamus and basal ganglia the most frequently affected areas, combined in some cases with frontal and temporal hypometabolism. Patients with a prion disease exhibit a characteristic pattern of brain metabolism presentation in FDG PET imaging. Consequently, in patients with rapidly progressive cognitive impairment, the detection of these patterns in the FDG PET study could orient the diagnosis to a prion disease.
Audiology and Neurotology, 2015
This article presents an analysis of the impact of functional neuroimaging studies (positron emis... more This article presents an analysis of the impact of functional neuroimaging studies (positron emission tomography, PET) in asymmetric hearing loss based on the clinical expertise obtained from a group of 21 patients. In these patients, PET studies are performed at rest and after auditory stimulation in order to measure the increase in brain activity in the ipsi-and contralateral cortex, providing supporting evidence to recommend a specific treatment and the side to implant. In conclusion, PET is a useful tool for selected cases in which information on the metabolic status of the auditory pathway can drive the decision regarding the treatment of the most appropriate ear. However, in view of our small sample, further research is needed to confirm our results in this topic.
Resumen.-La dihidrotetrabenazina (2-hidroxi-3-isobutil-9,10-dimetoxi-1,3,4,6,7-hexahidro-11bH-ben... more Resumen.-La dihidrotetrabenazina (2-hidroxi-3-isobutil-9,10-dimetoxi-1,3,4,6,7-hexahidro-11bH-benzo[a]-quinolizina, DTBZ) se ha convertido en el ligando ideal de los transportadores presinápticos de monoaminas (VMAT2) debido a su elevada afinidad de unión y su lipofilicidad.
![Research paper thumbnail of [Positron emission tomography in breast cancer]](https://attachments.academia-assets.com/45485361/thumbnails/1.jpg)
](Revista de medicina de la Universidad de Navarra
PET18FDG is an imaging diagnostic technique that shows changes in glycolitic metabolism that appe... more PET18FDG is an imaging diagnostic technique that shows changes in glycolitic metabolism that appear at a very early phases in the tumoral process. The main limitation of PET in breast cancer is the detection of small tumor lesions and axillary micrometastases. However it offers important information in the staging of high risk patients, in clinical relapse or in therapeutic evaluation. The new PET-CT devices offer advantages over conventional techniques. It provides a greater precision in the localization of tumoral foci. In spite of current difficulties for clinical applications, fluoro-estradiol (18F-ES) offers the possibilty of studying the presence of estrogenic receptors both in the primary and in the metastases. It may prove to be a useful tool to obtain information about therapeutic management and prognosis of breast cancer.
A high proportion of patients with Parkinson´s disease (PD) develop dementia. The profile of the ... more A high proportion of patients with Parkinson´s disease (PD) develop dementia. The profile of the cognitive deficits exhibited by these patients is different from the one typical of Alzheimer disease (AD). The brain metabolic dysfunction underlying dementia in AD is well established. In PD with dementia (PDD) some studies with SPECT 1-3 reveal a reduction of cerebral perfusion in parieto-occipital and temporal areas. However, only a few FDG PET studies 4-6 have been undertaken to define more precisely the pattern of brain hypometabolism. Equally, few comparative studies with AD FDG PET studies have been reported 7-8 . The aim of this study is to define the pattern of brain metabolism in AD and PDD and the differences between them.
Physica Medica, 2015
To assess the influence of reconstruction algorithms and parameters on the PET image quality of b... more To assess the influence of reconstruction algorithms and parameters on the PET image quality of brain phantoms in order to optimize reconstruction for clinical PET brain studies in a new generation PET/CT. The 3D Hoffman phantom that simulates (18)F-fluorodeoxyglucose (FDG) distribution was imaged in a Siemens Biograph mCT TrueV PET/CT with Time of Flight (TOF) and Point Spread Function (PSF) modelling. Contrast-to-Noise Ratio (CNR), contrast and noise were studied for different reconstruction models: OSEM, OSEM + TOF, OSEM + PSF and OSEM + PSF + TOF. The 2D multi-compartment Hoffman phantom was filled to simulate 4 different tracers' spatial distribution: FDG, (11)C-flumazenil (FMZ), (11)C-Methionine (MET) and 6-(18)F-fluoro-l-dopa (FDOPA). The best algorithm for each tracer was selected by visual inspection. The maximization of CNR determined the optimal parameters for each reconstruction. In the 3D Hoffman phantom, both noise and contrast increased with increasing number of iterations and decreased with increasing FWHM. OSEM + PSF + TOF reconstruction was generally superior to other reconstruction models. Visual analysis of the 2D Hoffman brain phantom suggested that OSEM + PSF + TOF is the optimum algorithm for tracers with focal uptake, such as MET or FDOPA, and OSEM + TOF for tracers with diffuse cortical uptake (i.e. FDG and FMZ). Optimization of CNR demonstrated that OSEM + TOF reconstruction must be performed with 2 iterations and a filter FWHM of 3 mm, and OSEM + PSF + TOF reconstruction with 4 iterations and 1 mm FWHM filter. Optimization of reconstruction algorithm and parameters has been performed to take particular advantage of the last generation PET scanner, recommending specific settings for different brain PET radiotracers.
European Journal of Nuclear Medicine and Molecular Imaging, 2015
Clinical diagnosis of human prion diseases can be challenging since symptoms are common to other ... more Clinical diagnosis of human prion diseases can be challenging since symptoms are common to other disorders associated with rapidly progressive dementia. In this context, (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) might be a useful complementary tool. The aim of this study was to determine the metabolic pattern in human prion diseases, particularly sporadic Creutzfeldt-Jakob disease (sCJD), the new variant of Creutzfeldt-Jakob disease (vCJD) and fatal familial insomnia (FFI). We retrospectively studied 17 patients with a definitive, probable or possible prion disease who underwent FDG PET in our institution. Of these patients, 12 were diagnosed as sCJD (9 definitive, 2 probable and 1 possible), 1 was diagnosed as definitive vCJD and 4 were diagnosed as definitive FFI. The hypometabolic pattern of each individual and comparisons across the groups of subjects (control subjects, sCJD and FFI) were evaluated using a voxel-based analysis. The sCJD group exhibited a pattern of hypometabolism that affected both subcortical (bilateral caudate, thalamus) and cortical (frontal cortex) structures, while the FFI group only presented a slight hypometabolism in the thalamus. Individual analysis demonstrated a considerable variability of metabolic patterns among patients, with the thalamus and basal ganglia the most frequently affected areas, combined in some cases with frontal and temporal hypometabolism. Patients with a prion disease exhibit a characteristic pattern of brain metabolism presentation in FDG PET imaging. Consequently, in patients with rapidly progressive cognitive impairment, the detection of these patterns in the FDG PET study could orient the diagnosis to a prion disease.
Audiology and Neurotology, 2015
This article presents an analysis of the impact of functional neuroimaging studies (positron emis... more This article presents an analysis of the impact of functional neuroimaging studies (positron emission tomography, PET) in asymmetric hearing loss based on the clinical expertise obtained from a group of 21 patients. In these patients, PET studies are performed at rest and after auditory stimulation in order to measure the increase in brain activity in the ipsi-and contralateral cortex, providing supporting evidence to recommend a specific treatment and the side to implant. In conclusion, PET is a useful tool for selected cases in which information on the metabolic status of the auditory pathway can drive the decision regarding the treatment of the most appropriate ear. However, in view of our small sample, further research is needed to confirm our results in this topic.
Resumen.-La dihidrotetrabenazina (2-hidroxi-3-isobutil-9,10-dimetoxi-1,3,4,6,7-hexahidro-11bH-ben... more Resumen.-La dihidrotetrabenazina (2-hidroxi-3-isobutil-9,10-dimetoxi-1,3,4,6,7-hexahidro-11bH-benzo[a]-quinolizina, DTBZ) se ha convertido en el ligando ideal de los transportadores presinápticos de monoaminas (VMAT2) debido a su elevada afinidad de unión y su lipofilicidad.
Revista de medicina de la Universidad de Navarra
PET18FDG is an imaging diagnostic technique that shows changes in glycolitic metabolism that appe... more PET18FDG is an imaging diagnostic technique that shows changes in glycolitic metabolism that appear at a very early phases in the tumoral process. The main limitation of PET in breast cancer is the detection of small tumor lesions and axillary micrometastases. However it offers important information in the staging of high risk patients, in clinical relapse or in therapeutic evaluation. The new PET-CT devices offer advantages over conventional techniques. It provides a greater precision in the localization of tumoral foci. In spite of current difficulties for clinical applications, fluoro-estradiol (18F-ES) offers the possibilty of studying the presence of estrogenic receptors both in the primary and in the metastases. It may prove to be a useful tool to obtain information about therapeutic management and prognosis of breast cancer.