Improved frame-based estimation of head motion in PET brain imaging

Energy Technology Data Exchange (ETDEWEB)

Mukherjee, J. M., E-mail: joyeeta.mitra@umassmed.edu; Lindsay, C.; King, M. A.; Licho, R. [Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655 (United States); Mukherjee, A. [Aware, Inc., Bedford, Massachusetts 01730 (United States); Olivier, P. [Philips Medical Systems, Cleveland, Ohio 44143 (United States); Shao, L. [ViewRay, Oakwood Village, Ohio 44146 (United States)

2016-05-15

Purpose: Head motion during PET brain imaging can cause significant degradation of image quality. Several authors have proposed ways to compensate for PET brain motion to restore image quality and improve quantitation. Head restraints can reduce movement but are unreliable; thus the need for alternative strategies such as data-driven motion estimation or external motion tracking. Herein, the authors present a data-driven motion estimation method using a preprocessing technique that allows the usage of very short duration frames, thus reducing the intraframe motion problem commonly observed in the multiple frame acquisition method. Methods: The list mode data for PET acquisition is uniformly divided into 5-s frames and images are reconstructed without attenuation correction. Interframe motion is estimated using a 3D multiresolution registration algorithm and subsequently compensated for. For this study, the authors used 8 PET brain studies that used F-18 FDG as the tracer and contained minor or no initial motion. After reconstruction and prior to motion estimation, known motion was introduced to each frame to simulate head motion during a PET acquisition. To investigate the trade-off in motion estimation and compensation with respect to frames of different length, the authors summed 5-s frames accordingly to produce 10 and 60 s frames. Summed images generated from the motion-compensated reconstructed frames were then compared to the original PET image reconstruction without motion compensation. Results: The authors found that our method is able to compensate for both gradual and step-like motions using frame times as short as 5 s with a spatial accuracy of 0.2 mm on average. Complex volunteer motion involving all six degrees of freedom was estimated with lower accuracy (0.3 mm on average) than the other types investigated. Preprocessing of 5-s images was necessary for successful image registration. Since their method utilizes nonattenuation corrected frames, it is

Integrated three-dimensional display of MR, CT, and PET images of the brain

International Nuclear Information System (INIS)

Levin, D.N.; Herrmann, A.; Chen, G.T.Y.

1988-01-01

MR, CT, and PET studies depict complementary aspects of brain anatomy and function. The authors' own image-processing software and a Pixar image computer were used to create three-dimensional models of brain soft tissues from MR images, of the skull and calcifications from CT scans, and of brain metabolism from PET images. An image correlation program, based on surface fitting, was used for retrospective registration and merging of these three-dimensional models. The results are demonstrated in a video clip showing how the operator may rotate and perform electronic surgery on the integrated, multimodality three-dimensional model of each patient's brain

Simultaneous MRI and PET imaging of a rat brain

Energy Technology Data Exchange (ETDEWEB)

Raylman, Raymond R [Center for Advanced Imaging, Department of Radiology, Box 9236, West Virginia University, Morgantown, WV (United States); Majewski, Stan [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave., Newport News, VA (United States); Lemieux, Susan K [Center for Advanced Imaging, Department of Radiology, Box 9236, West Virginia University, Morgantown, WV (United States); Velan, S Sendhil [Center for Advanced Imaging, Department of Radiology, Box 9236, West Virginia University, Morgantown, WV (United States); Kross, Brian [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave., Newport News, VA (United States); Popov, Vladimir [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave., Newport News, VA (United States); Smith, Mark F [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave., Newport News, VA (United States); Weisenberger, Andrew G [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave., Newport News, VA (United States); Zorn, Carl [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave., Newport News, VA (United States); Marano, Gary D [Center for Advanced Imaging, Department of Radiology, Box 9236, West Virginia University, Morgantown, WV (United States)

2006-12-21

Multi-modality imaging is rapidly becoming a valuable tool in the diagnosis of disease and in the development of new drugs. Functional images produced with PET fused with anatomical structure images created by MRI will allow the correlation of form with function. Our group is developing a system to acquire MRI and PET images contemporaneously. The prototype device consists of two opposed detector heads, operating in coincidence mode. Each MRI-PET detector module consists of an array of LSO detector elements coupled through a long fibre optic light guide to a single Hamamatsu flat panel position-sensitive photomultiplier tube (PSPMT). The use of light guides allows the PSPMTs to be positioned outside the bore of a 3T MRI scanner where the magnetic field is relatively small. To test the device, simultaneous MRI and PET images of the brain of a male Sprague Dawley rat injected with FDG were successfully obtained. The images revealed no noticeable artefacts in either image set. Future work includes the construction of a full ring PET scanner, improved light guides and construction of a specialized MRI coil to permit higher quality MRI imaging.

Simultaneous MRI and PET imaging of a rat brain

International Nuclear Information System (INIS)

Raylman, Raymond R; Majewski, Stan; Lemieux, Susan K; Velan, S Sendhil; Kross, Brian; Popov, Vladimir; Smith, Mark F; Weisenberger, Andrew G; Zorn, Carl; Marano, Gary D

2006-01-01

Multi-modality imaging is rapidly becoming a valuable tool in the diagnosis of disease and in the development of new drugs. Functional images produced with PET fused with anatomical structure images created by MRI will allow the correlation of form with function. Our group is developing a system to acquire MRI and PET images contemporaneously. The prototype device consists of two opposed detector heads, operating in coincidence mode. Each MRI-PET detector module consists of an array of LSO detector elements coupled through a long fibre optic light guide to a single Hamamatsu flat panel position-sensitive photomultiplier tube (PSPMT). The use of light guides allows the PSPMTs to be positioned outside the bore of a 3T MRI scanner where the magnetic field is relatively small. To test the device, simultaneous MRI and PET images of the brain of a male Sprague Dawley rat injected with FDG were successfully obtained. The images revealed no noticeable artefacts in either image set. Future work includes the construction of a full ring PET scanner, improved light guides and construction of a specialized MRI coil to permit higher quality MRI imaging

Dedicated brain PET system of PET/MR for brain research

International Nuclear Information System (INIS)

Cheng, Li; Liu, Yaqiang; Ma, Tianyu; Wang, Shi; Wei, Qingyang; Xu, Tianpeng

2015-01-01

This work is to replace PET ring in human brain PET/MR system with a dedicated wearable PET insert, aimed at improving both patient feasibility and system performance for brain imaging. The designed PET/MR system includes two parts: the inside parts, including a radio frequency (RF) coil and PET ring, are mounted on patient’s head, and the outside part, a MR imager, is dependent of patient. The RF coil is the innermost layer, surrounded by an outer PET-ring layer. They are supported by a MRcompatible structure. And both RF coil and PET detectors are placed inside a standard clinical 3-T MR imager. From the design of the system we can infer that some advantages can be achieved. First, high sensitivity will be achieved with the same amount crystals as the PET ring is more close to region-of-interest area, at a reduced cost. Second, by using a 2-layer depth of interaction (DOI) detector, the parallax effect can be minimized. The resolution will benefit from short positron range caused by magnetic field and smaller ring diameter will also reduce the effect of non-collinearity. Thirdly, as the PET ring is mounted on head, impact of patient motion will be reduced.

Dedicated brain PET system of PET/MR for brain research

Energy Technology Data Exchange (ETDEWEB)

Cheng, Li; Liu, Yaqiang; Ma, Tianyu; Wang, Shi; Wei, Qingyang; Xu, Tianpeng [Institute of Medical Physics, Department of Engineering Physics, Tsinghua University, Beijing (China)

2015-05-18

This work is to replace PET ring in human brain PET/MR system with a dedicated wearable PET insert, aimed at improving both patient feasibility and system performance for brain imaging. The designed PET/MR system includes two parts: the inside parts, including a radio frequency (RF) coil and PET ring, are mounted on patient’s head, and the outside part, a MR imager, is dependent of patient. The RF coil is the innermost layer, surrounded by an outer PET-ring layer. They are supported by a MRcompatible structure. And both RF coil and PET detectors are placed inside a standard clinical 3-T MR imager. From the design of the system we can infer that some advantages can be achieved. First, high sensitivity will be achieved with the same amount crystals as the PET ring is more close to region-of-interest area, at a reduced cost. Second, by using a 2-layer depth of interaction (DOI) detector, the parallax effect can be minimized. The resolution will benefit from short positron range caused by magnetic field and smaller ring diameter will also reduce the effect of non-collinearity. Thirdly, as the PET ring is mounted on head, impact of patient motion will be reduced.

Application of PET in brain tumor

International Nuclear Information System (INIS)

Chung, June Key

2002-01-01

The annual incidence of primary brain tumors is 7-19 cases per 100,000 people. The unique capacity of visualizing biochemical processes allows PET to determine functional metabolic activities of the brain tumors. Like other malignant tumors, F-18 FDG has been used commonly in the imaging of brain tumors. FDG PET is valuable in grading malignancy, predicting prognosis, monitoring treatment, differentiating tumor recurrence from radiation nucrosis, and detecting primary lesion in metastatric brain tumors. Among amino acids labeled with positron emitters, C-11 methionine is used clinically.Tumor delineation is much better with methionine PET than with FDG PET. Low grade gliomas, in particular, are better evaluated with methionine than with FDG. PET opens another dimension in brain tumor imaging. PET imaging has clearly entered the clinical area with a profound impact on patient care in many indications

Images to visualize the brain. PET: Positron Emission Tomography

International Nuclear Information System (INIS)

1992-01-01

Diagnosis instrument and research tool, Positron Emission Tomography permits advanced technological developments on positron camera, on molecule labelling and principally on very complex 3D image processing. Cyceron Centre in Caen-France works on brain diseases and try to understand the mechanism of observed troubles and to assess the treatment efficiency with PET. Service Hospitalier Frederic Joliot of CEA-France establishes a mapping of cognitive functions in PET as vision areas, anxiety regions, brain organization of language, different attention forms, voluntary actions and motor functions

Applying Amide Proton Transfer MR Imaging to Hybrid Brain PET/MR: Concordance with Gadolinium Enhancement and Added Value to [18F]FDG PET.

Science.gov (United States)

Sun, Hongzan; Xin, Jun; Zhou, Jinyuan; Lu, Zaiming; Guo, Qiyong

2018-06-01

The purpose of this study is to evaluate the diagnostic concordance and metric correlations of amide proton transfer (APT) imaging with gadolinium-enhanced magnetic resonance imaging (MRI) and 2-deoxy-2-[ 18 F-]fluoro-D-glucose ([ 18 F]FDG) positron emission tomography (PET), using hybrid brain PET/MRI. Twenty-one subjects underwent brain gadolinium-enhanced [ 18 F]FDG PET/MRI prospectively. Imaging accuracy was compared between unenhanced MRI, MRI with enhancement, APT-weighted (APTW) images, and PET based on six diagnostic criteria. Among tumors, the McNemar test was further used for concordance assessment between gadolinium-enhanced imaging, APT imaging, and [ 18 F]FDG PET. As well, the relation of metrics between APT imaging and PET was analyzed by the Pearson correlation analysis. APT imaging and gadolinium-enhanced MRI showed superior and similar diagnostic accuracy. APTW signal intensity and gadolinium enhancement were concordant in 19 tumors (100 %), while high [ 18 F]FDG avidity was shown in only 12 (63.2 %). For the metrics from APT imaging and PET, there was significant correlation for 13 hypermetabolic tumors (P PET in the evaluation of tumor metabolic activity during brain PET/MR studies.

Reproducibility of Quantitative Brain Imaging Using a PET-Only and a Combined PET/MR System

DEFF Research Database (Denmark)

Lassen, Martin L; Muzik, Otto; Beyer, Thomas

2017-01-01

The purpose of this study was to test the feasibility of migrating a quantitative brain imaging protocol from a positron emission tomography (PET)-only system to an integrated PET/MR system. Potential differences in both absolute radiotracer concentration as well as in the derived kinetic paramet...

Radiolabelling and PET brain imaging of the α1-adrenoceptor antagonist Lu AE43936

International Nuclear Information System (INIS)

Risgaard, Rune; Ettrup, Anders; Balle, Thomas; Dyssegaard, Agnete; Hansen, Hanne Demant; Lehel, Szabolcs; Madsen, Jacob; Pedersen, Henrik; Püschl, Ask; Badolo, Lassina; Bang-Andersen, Benny; Knudsen, Gitte Moos; Kristensen, Jesper Langgaard

2013-01-01

Cerebral α 1 -adrenoceptors are a common target for many antipsychotic drugs. Thus, access to positron emission tomography (PET) brain imaging of α 1 -adrenoceptors could make important contributions to the understanding of psychotic disorders as well as to the pharmacokinetics and occupancy of drugs targeting the α 1 -adrenoceptors. However, so far no suitable PET radioligand has been developed for brain imaging of α 1 -adrenoceptors. Here, we report the synthesis of both enantiomers of the desmethyl precursors of the high affinity α 1 -adrenoceptor ligand Lu AE43936 (). The two enantiomers of were subsequently [ 11 C] radiolabelled and evaluated for brain uptake and binding by PET imaging in Danish Landrace pigs. (S)-[ 11 C]- and (R)-[ 11 C]- showed very limited brain uptake. Pre-treatment with cyclosporine A (CsA) resulted in a large increase in brain uptake, indicating that (R)-[ 11 C]- is a substrate for active efflux-transporters. This was confirmed in Madin Darby canine kidney (MDCK) cells overexpressing permeability glycoprotein (Pgp). In conclusion, the limited brain uptake of both (S)-[ 11 C]- and (R)-[ 11 C]- in the pig brain necessitates the search for alternative radioligands for in vivo PET brain imaging of α 1 -adrenoceptors.

The study on acquisition mode and reconstruction parameters of brain FDG PET images

International Nuclear Information System (INIS)

Zuo Chuantao; Liu Yongchang; Guan Yihui; Zhao Jun; Lin Xiangtong

2001-01-01

Objective: To evaluate the effect of acquisition mode on the brain PET images. Methods: After changing conditions and parameters, the authors got brain PET images of different acquisition modes, different emission counts, different transmission times; and compared with the reference images the impacts of different acquisition modes, different acquisition conditions were assessed. Results: Compared with 2D mode, much higher background and noise were observed on the reconstruction images of 3D mode, and the bottoms of the brain structure were not well displayed. But the middle part of brain structure displayed well in 2D and 3D mode without difference; the gray/white radioactivity ratios were 2.108 +- 0.183 and 2.286 +- 0.232 under 2D and 3D mode, respectively. The gray/white radioactivity ratios with different emission counts were 2.108 +- 0.183, 2.215 +- 0.158, 2.161 +- 0.176, respectively, there was no evident difference among them. With transmission counts increasing, the segmented image outline of Hoffman phantom and brain structure became clear and integral. Conclusions: Different acquisition modes, different emission counts and different transmission times are of certain impacts on brain FDG PET images, and it should be paid more attention in clinical practice

Automatic delineation of brain regions on MRI and PET images from the pig.

Science.gov (United States)

Villadsen, Jonas; Hansen, Hanne D; Jørgensen, Louise M; Keller, Sune H; Andersen, Flemming L; Petersen, Ida N; Knudsen, Gitte M; Svarer, Claus

2018-01-15

The increasing use of the pig as a research model in neuroimaging requires standardized processing tools. For example, extraction of regional dynamic time series from brain PET images requires parcellation procedures that benefit from being automated. Manual inter-modality spatial normalization to a MRI atlas is operator-dependent, time-consuming, and can be inaccurate with lack of cortical radiotracer binding or skull uptake. A parcellated PET template that allows for automatic spatial normalization to PET images of any radiotracer. MRI and [ 11 C]Cimbi-36 PET scans obtained in sixteen pigs made the basis for the atlas. The high resolution MRI scans allowed for creation of an accurately averaged MRI template. By aligning the within-subject PET scans to their MRI counterparts, an averaged PET template was created in the same space. We developed an automatic procedure for spatial normalization of the averaged PET template to new PET images and hereby facilitated transfer of the atlas regional parcellation. Evaluation of the automatic spatial normalization procedure found the median voxel displacement to be 0.22±0.08mm using the MRI template with individual MRI images and 0.92±0.26mm using the PET template with individual [ 11 C]Cimbi-36 PET images. We tested the automatic procedure by assessing eleven PET radiotracers with different kinetics and spatial distributions by using perfusion-weighted images of early PET time frames. We here present an automatic procedure for accurate and reproducible spatial normalization and parcellation of pig PET images of any radiotracer with reasonable blood-brain barrier penetration. Copyright © 2017 Elsevier B.V. All rights reserved.

SPECT and PET Serve as Molecular Imaging Techniques and in Vivo Biomarkers for Brain Metastases

Science.gov (United States)

Palumbo, Barbara; Buresta, Tommaso; Nuvoli, Susanna; Spanu, Angela; Schillaci, Orazio; Fravolini, Mario Luca; Palumbo, Isabella

2014-01-01

Nuclear medicine techniques (single photon emission computerized tomography, SPECT, and positron emission tomography, PET) represent molecular imaging tools, able to provide in vivo biomarkers of different diseases. To investigate brain tumours and metastases many different radiopharmaceuticals imaged by SPECT and PET can be used. In this review the main and most promising radiopharmaceuticals available to detect brain metastases are reported. Furthermore the diagnostic contribution of the combination of SPECT and PET data with radiological findings (magnetic resonance imaging, MRI) is discussed. PMID:24897023

SPECT and PET Serve as Molecular Imaging Techniques and in Vivo Biomarkers for Brain Metastases

Directory of Open Access Journals (Sweden)

Barbara Palumbo

2014-06-01

Full Text Available Nuclear medicine techniques (single photon emission computerized tomography, SPECT, and positron emission tomography, PET represent molecular imaging tools, able to provide in vivo biomarkers of different diseases. To investigate brain tumours and metastases many different radiopharmaceuticals imaged by SPECT and PET can be used. In this review the main and most promising radiopharmaceuticals available to detect brain metastases are reported. Furthermore the diagnostic contribution of the combination of SPECT and PET data with radiological findings (magnetic resonance imaging, MRI is discussed.

Structured light 3D tracking system for measuring motions in PET brain imaging

DEFF Research Database (Denmark)

Olesen, Oline Vinter; Jørgensen, Morten Rudkjær; Paulsen, Rasmus Reinhold

2010-01-01

Patient motion during scanning deteriorates image quality, especially for high resolution PET scanners. A new proposal for a 3D head tracking system for motion correction in high resolution PET brain imaging is set up and demonstrated. A prototype tracking system based on structured light with a ...

Evaluation of MLACF based calculated attenuation brain PET imaging for FDG patient studies

Science.gov (United States)

Bal, Harshali; Panin, Vladimir Y.; Platsch, Guenther; Defrise, Michel; Hayden, Charles; Hutton, Chloe; Serrano, Benjamin; Paulmier, Benoit; Casey, Michael E.

2017-04-01

Calculating attenuation correction for brain PET imaging rather than using CT presents opportunities for low radiation dose applications such as pediatric imaging and serial scans to monitor disease progression. Our goal is to evaluate the iterative time-of-flight based maximum-likelihood activity and attenuation correction factors estimation (MLACF) method for clinical FDG brain PET imaging. FDG PET/CT brain studies were performed in 57 patients using the Biograph mCT (Siemens) four-ring scanner. The time-of-flight PET sinograms were acquired using the standard clinical protocol consisting of a CT scan followed by 10 min of single-bed PET acquisition. Images were reconstructed using CT-based attenuation correction (CTAC) and used as a gold standard for comparison. Two methods were compared with respect to CTAC: a calculated brain attenuation correction (CBAC) and MLACF based PET reconstruction. Plane-by-plane scaling was performed for MLACF images in order to fix the variable axial scaling observed. The noise structure of the MLACF images was different compared to those obtained using CTAC and the reconstruction required a higher number of iterations to obtain comparable image quality. To analyze the pooled data, each dataset was registered to a standard template and standard regions of interest were extracted. An SUVr analysis of the brain regions of interest showed that CBAC and MLACF were each well correlated with CTAC SUVrs. A plane-by-plane error analysis indicated that there were local differences for both CBAC and MLACF images with respect to CTAC. Mean relative error in the standard regions of interest was less than 5% for both methods and the mean absolute relative errors for both methods were similar (3.4%  ±  3.1% for CBAC and 3.5%  ±  3.1% for MLACF). However, the MLACF method recovered activity adjoining the frontal sinus regions more accurately than CBAC method. The use of plane-by-plane scaling of MLACF images was found to be a

In vivo imaging of brain androgen receptors in rats: a [18F]FDHT PET study

International Nuclear Information System (INIS)

Khayum, M.A.; Doorduin, J.; Antunes, I.F.; Kwizera, C.; Zijlma, R.; Boer, J.A. den; Dierckx, R.A.J.O.; Vries, E.F.J. de

2015-01-01

Introduction: Steroid hormones like androgens play an important role in the development and maintenance of several brain functions. Androgens can act through androgen receptors (AR) in the brain. This study aims to demonstrate the feasibility of positron emission tomography (PET) with 16β-[ 18 F]fluoro-5α-dihydrotestosterone ([ 18 F]FDHT) to image AR expression in the brain. Methods: Male Wistar rats were either orchiectomized to inhibit endogenous androgen production or underwent sham-surgery. Fifteen days after surgery, rats were subjected to a 90-min dynamic [ 18 F]FDHT PET scan with arterial blood sampling. In a subset of orchiectomized rats, 1 mg/kg dihydrotestosterone was co-injected with the tracer in order to saturate the AR. Plasma samples were analyzed for the presence of radioactive metabolites by radio-TLC. Pharmacokinetic modeling was performed to quantify brain kinetics of the tracer. After the PET scan, the animals were terminated for ex-vivo biodistribution. Results: PET imaging and ex vivo biodistribution studies showed low [ 18 F]FDHT uptake in all brain regions, except pituitary. [ 18 F]FDHT uptake in the surrounding cranial bones was high and increased over time. [ 18 F]FDHT was rapidly metabolized in rats. Metabolism was significantly faster in orchiectomized rats than in sham-orchiectomized rats. Quantitative analysis of PET data indicated substantial spill-over of activity from cranial bones into peripheral brain regions, which prevented further analysis of peripheral brain regions. Logan graphical analysis and kinetic modeling using 1- and 2-tissue compartment models showed reversible and homogenously distributed tracer uptake in central brain regions. [ 18 F]FDHT uptake in the brain could not be blocked by endogenous androgens or administration of dihydrotestosterone. Conclusion: The results of this study indicate that imaging of AR availability in rat brain with [ 18 F]FDHT PET is not feasible. The low AR expression in the brain, the

Effects of attenuation and scatter corrections in cat brain PET images using microPET R4 scanner

International Nuclear Information System (INIS)

Kim, Jin Su; Lee, Jae Sung; Lee, Jong Jin

2006-01-01

The aim of this study was to examine the effects of attenuation correction (AC) and scatter correction (SC) on the quantification of PET count rates. To assess the effects of AC and SC, 18 F-FDG PET images of phantom and cat brain were acquired using microPET R4 scanner. Thirty-minute transmission images using 68 Ge source and emission images after injection of FDG were acquired. PET images were reconstructed using. 2D OSEM. AC and SC were applied. Regional count rates were measured using ROls drawn on cerebral cortex including frontal, parietal, and latral temporal lobes and deep gray matter including head of caudate nucleus, putamen and thalamus for pre- and post-AC and SC images. The count rates were then normalized with the injected dose per body weight. To assess the effects of AC, count ratio of 'deep gray matter/cerebral cortex' was calculated. To assess the effects of SC, ROls were also drawn on the gray matter (GM) and white matter (WM), and contrast between them ((GM-WM)/GM) was measured. After the AC, count ratio of 'deep gray matter/cerebral cortex' was increased by 17±7%. After the SC, contrast was also increased by 12±3%. Relative count of deep gray matter and contrast between gray and white matters were increased after AC and SC, suggesting that the AC would be critical for the quantitative analysis of cat brain PET data

Errors in MR-based attenuation correction for brain imaging with PET/MR scanners

International Nuclear Information System (INIS)

Rota Kops, Elena; Herzog, Hans

2013-01-01

Aim: Attenuation correction of PET data acquired by hybrid MR/PET scanners remains a challenge, even if several methods for brain and whole-body measurements have been developed recently. A template-based attenuation correction for brain imaging proposed by our group is easy to handle and delivers reliable attenuation maps in a short time. However, some potential error sources are analyzed in this study. We investigated the choice of template reference head among all the available data (error A), and possible skull anomalies of the specific patient, such as discontinuities due to surgery (error B). Materials and methods: An anatomical MR measurement and a 2-bed-position transmission scan covering the whole head and neck region were performed in eight normal subjects (4 females, 4 males). Error A: Taking alternatively one of the eight heads as reference, eight different templates were created by nonlinearly registering the images to the reference and calculating the average. Eight patients (4 females, 4 males; 4 with brain lesions, 4 w/o brain lesions) were measured in the Siemens BrainPET/MR scanner. The eight templates were used to generate the patients' attenuation maps required for reconstruction. ROI and VOI atlas-based comparisons were performed employing all the reconstructed images. Error B: CT-based attenuation maps of two volunteers were manipulated by manually inserting several skull lesions and filling a nasal cavity. The corresponding attenuation coefficients were substituted with the water's coefficient (0.096/cm). Results: Error A: The mean SUVs over the eight templates pairs for all eight patients and all VOIs did not differ significantly one from each other. Standard deviations up to 1.24% were found. Error B: After reconstruction of the volunteers' BrainPET data with the CT-based attenuation maps without and with skull anomalies, a VOI-atlas analysis was performed revealing very little influence of the skull lesions (less than 3%), while the filled

Errors in MR-based attenuation correction for brain imaging with PET/MR scanners

Science.gov (United States)

Rota Kops, Elena; Herzog, Hans

2013-02-01

AimAttenuation correction of PET data acquired by hybrid MR/PET scanners remains a challenge, even if several methods for brain and whole-body measurements have been developed recently. A template-based attenuation correction for brain imaging proposed by our group is easy to handle and delivers reliable attenuation maps in a short time. However, some potential error sources are analyzed in this study. We investigated the choice of template reference head among all the available data (error A), and possible skull anomalies of the specific patient, such as discontinuities due to surgery (error B). Materials and methodsAn anatomical MR measurement and a 2-bed-position transmission scan covering the whole head and neck region were performed in eight normal subjects (4 females, 4 males). Error A: Taking alternatively one of the eight heads as reference, eight different templates were created by nonlinearly registering the images to the reference and calculating the average. Eight patients (4 females, 4 males; 4 with brain lesions, 4 w/o brain lesions) were measured in the Siemens BrainPET/MR scanner. The eight templates were used to generate the patients' attenuation maps required for reconstruction. ROI and VOI atlas-based comparisons were performed employing all the reconstructed images. Error B: CT-based attenuation maps of two volunteers were manipulated by manually inserting several skull lesions and filling a nasal cavity. The corresponding attenuation coefficients were substituted with the water's coefficient (0.096/cm). ResultsError A: The mean SUVs over the eight templates pairs for all eight patients and all VOIs did not differ significantly one from each other. Standard deviations up to 1.24% were found. Error B: After reconstruction of the volunteers' BrainPET data with the CT-based attenuation maps without and with skull anomalies, a VOI-atlas analysis was performed revealing very little influence of the skull lesions (less than 3%), while the filled nasal

Application of cross-species PET imaging to assess neurotransmitter release in brain.

Science.gov (United States)

Finnema, Sjoerd J; Scheinin, Mika; Shahid, Mohammed; Lehto, Jussi; Borroni, Edilio; Bang-Andersen, Benny; Sallinen, Jukka; Wong, Erik; Farde, Lars; Halldin, Christer; Grimwood, Sarah

2015-11-01

This review attempts to summarize the current status in relation to the use of positron emission tomography (PET) imaging in the assessment of synaptic concentrations of endogenous mediators in the living brain. Although PET radioligands are now available for more than 40 CNS targets, at the initiation of the Innovative Medicines Initiative (IMI) "Novel Methods leading to New Medications in Depression and Schizophrenia" (NEWMEDS) in 2009, PET radioligands sensitive to an endogenous neurotransmitter were only validated for dopamine. NEWMEDS work-package 5, "Cross-species and neurochemical imaging (PET) methods for drug discovery", commenced with a focus on developing methods enabling assessment of changes in extracellular concentrations of serotonin and noradrenaline in the brain. Sharing the workload across institutions, we utilized in vitro techniques with cells and tissues, in vivo receptor binding and microdialysis techniques in rodents, and in vivo PET imaging in non-human primates and humans. Here, we discuss these efforts and review other recently published reports on the use of radioligands to assess changes in endogenous levels of dopamine, serotonin, noradrenaline, γ-aminobutyric acid, glutamate, acetylcholine, and opioid peptides. The emphasis is on assessment of the availability of appropriate translational tools (PET radioligands, pharmacological challenge agents) and on studies in non-human primates and human subjects, as well as current challenges and future directions. PET imaging directed at investigating changes in endogenous neurochemicals, including the work done in NEWMEDS, have highlighted an opportunity to further extend the capability and application of this technology in drug development.

Quantitative Evaluation of Atlas-based Attenuation Correction for Brain PET in an Integrated Time-of-Flight PET/MR Imaging System.

Science.gov (United States)

Yang, Jaewon; Jian, Yiqiang; Jenkins, Nathaniel; Behr, Spencer C; Hope, Thomas A; Larson, Peder E Z; Vigneron, Daniel; Seo, Youngho

2017-07-01

Purpose To assess the patient-dependent accuracy of atlas-based attenuation correction (ATAC) for brain positron emission tomography (PET) in an integrated time-of-flight (TOF) PET/magnetic resonance (MR) imaging system. Materials and Methods Thirty recruited patients provided informed consent in this institutional review board-approved study. All patients underwent whole-body fluorodeoxyglucose PET/computed tomography (CT) followed by TOF PET/MR imaging. With use of TOF PET data, PET images were reconstructed with four different attenuation correction (AC) methods: PET with patient CT-based AC (CTAC), PET with ATAC (air and bone from an atlas), PET with ATAC patientBone (air and tissue from the atlas with patient bone), and PET with ATAC boneless (air and tissue from the atlas without bone). For quantitative evaluation, PET mean activity concentration values were measured in 14 1-mL volumes of interest (VOIs) distributed throughout the brain and statistical significance was tested with a paired t test. Results The mean overall difference (±standard deviation) of PET with ATAC compared with PET with CTAC was -0.69 kBq/mL ± 0.60 (-4.0% ± 3.2) (P PET with ATAC boneless (-9.4% ± 3.7) was significantly worse than that of PET with ATAC (-4.0% ± 3.2) (P PET with ATAC patientBone (-1.5% ± 1.5) improved over that of PET with ATAC (-4.0% ± 3.2) (P PET/MR imaging achieves similar quantification accuracy to that from CTAC by means of atlas-based bone compensation. However, patient-specific anatomic differences from the atlas causes bone attenuation differences and misclassified sinuses, which result in patient-dependent performance variation of ATAC. © RSNA, 2017 Online supplemental material is available for this article.

Reproducibility of Quantitative Brain Imaging Using a PET-Only and a Combined PET/MR System

Directory of Open Access Journals (Sweden)

Martin L. Lassen

2017-07-01

Full Text Available The purpose of this study was to test the feasibility of migrating a quantitative brain imaging protocol from a positron emission tomography (PET-only system to an integrated PET/MR system. Potential differences in both absolute radiotracer concentration as well as in the derived kinetic parameters as a function of PET system choice have been investigated. Five healthy volunteers underwent dynamic (R-[11C]verapamil imaging on the same day using a GE-Advance (PET-only and a Siemens Biograph mMR system (PET/MR. PET-emission data were reconstructed using a transmission-based attenuation correction (AC map (PET-only, whereas a standard MR-DIXON as well as a low-dose CT AC map was applied to PET/MR emission data. Kinetic modeling based on arterial blood sampling was performed using a 1-tissue-2-rate constant compartment model, yielding kinetic parameters (K1 and k2 and distribution volume (VT. Differences for parametric values obtained in the PET-only and the PET/MR systems were analyzed using a 2-way Analysis of Variance (ANOVA. Comparison of DIXON-based AC (PET/MR with emission data derived from the PET-only system revealed average inter-system differences of −33 ± 14% (p < 0.05 for the K1 parameter and −19 ± 9% (p < 0.05 for k2. Using a CT-based AC for PET/MR resulted in slightly lower systematic differences of −16 ± 18% for K1 and −9 ± 10% for k2. The average differences in VT were −18 ± 10% (p < 0.05 for DIXON- and −8 ± 13% for CT-based AC. Significant systematic differences were observed for kinetic parameters derived from emission data obtained from PET/MR and PET-only imaging due to different standard AC methods employed. Therefore, a transfer of imaging protocols from PET-only to PET/MR systems is not straightforward without application of proper correction methods.Clinical Trial Registration:www.clinicaltrialsregister.eu, identifier 2013-001724-19

Dynamic Functional Imaging of Brain Glucose Utilization using fPET-FDG

Science.gov (United States)

Villien, Marjorie; Wey, Hsiao-Ying; Mandeville, Joseph B.; Catana, Ciprian; Polimeni, Jonathan R.; Sander, Christin Y.; Zürcher, Nicole R.; Chonde, Daniel B.; Fowler, Joanna S.; Rosen, Bruce R.; Hooker, Jacob M.

2014-01-01

Glucose is the principal source of energy for the brain and yet the dynamic response of glucose utilization to changes in brain activity is still not fully understood. Positron emission tomography (PET) allows quantitative measurement of glucose metabolism using 2-[18F]-fluorodeoxyglucose (FDG). However, FDG PET in its current form provides an integral (or average) of glucose consumption over tens of minutes and lacks the temporal information to capture physiological alterations associated with changes in brain activity induced by tasks or drug challenges. Traditionally, changes in glucose utilization are inferred by comparing two separate scans, which significantly limits the utility of the method. We report a novel method to track changes in FDG metabolism dynamically, with higher temporal resolution than exists to date and within a single session. Using a constant infusion of FDG, we demonstrate that our technique (termed fPET-FDG) can be used in an analysis pipeline similar to fMRI to define within-session differential metabolic responses. We use visual stimulation to demonstrate the feasibility of this method. This new method has a great potential to be used in research protocols and clinical settings since fPET-FDG imaging can be performed with most PET scanners and data acquisition and analysis is straightforward. fPET-FDG is a highly complementary technique to MRI and provides a rich new way to observe functional changes in brain metabolism. PMID:24936683

Motion correction in simultaneous PET/MR brain imaging using sparsely sampled MR navigators

DEFF Research Database (Denmark)

Keller, Sune H; Hansen, Casper; Hansen, Christian

2015-01-01

BACKGROUND: We present a study performing motion correction (MC) of PET using MR navigators sampled between other protocolled MR sequences during simultaneous PET/MR brain scanning with the purpose of evaluating its clinical feasibility and the potential improvement of image quality. FINDINGS......: Twenty-nine human subjects had a 30-min [(11)C]-PiB PET scan with simultaneous MR including 3D navigators sampled at six time points, which were used to correct the PET image for rigid head motion. Five subjects with motion greater than 4 mm were reconstructed into six frames (one for each navigator...

Brain tumour imaging with PET: a comparison between [18F]fluorodopa and [11C]methionine

International Nuclear Information System (INIS)

Becherer, Alexander; Karanikas, Georgios; Szabo, Monica; Zettinig, Georg; Wadsak, Wolfgang; Kletter, Kurt; Asenbaum, Susanne; Marosi, Christine; Henk, Christine; Wunderbaldinger, Patrick; Czech, Thomas

2003-01-01

Imaging of amino acid transport in brain tumours is more sensitive than fluorine-18 2-fluoro-deoxyglucose positron emission tomography (PET). The most frequently used tracer in this field is carbon-11 methionine (MET), which is unavailable for PET centres without a cyclotron because of its short half-life. The purpose of this study was to evaluate the performance of 3,4-dihydroxy-6-[ 18 F]fluoro-phenylalanine (FDOPA) in this setting, in comparison with MET. Twenty patients with known supratentorial brain lesions were referred for PET scans with FDOPA and MET. The diagnoses were 18 primary brain tumours, one metastasis and one non-neoplastic cerebral lesion. All 20 patients underwent PET with FDOPA (100 MBq, 20 min p.i.), and 19 of them also had PET scans with MET (800 MBq, 20 min p.i.). In all but one patient a histological diagnosis was available. In 15 subjects, histology was known from previous surgical interventions; in five of these patients, as well as in four previously untreated patients, histology was obtained after PET. In one untreated patient, confirmation of PET was possible solely by correlation with MRI; a histological diagnosis became available 10 months later. MET and FDOPA images matched in all patients and showed all lesions as hot spots with higher uptake than in the contralateral brain. Standardised uptake value ratios, tumour/contralateral side (mean±SD), were 2.05±0.91 for MET and 2.04±0.53 for FDOPA (NS). The benign lesion, which biopsy revealed to be a focal demyelination, was false positive, showing increased uptake of MET and FDOPA. We conclude that FDOPA is accurate as a surrogate for MET in imaging amino acid transport in malignant cerebral lesions for the purpose of visualisation of vital tumour tissue. It combines the good physical properties of 18 F with the pharmacological properties of MET and might therefore be a valuable PET radiopharmaceutical in brain tumour imaging. (orig.)

Acupuncture of Weizhong (BL 40) and Zusanli (ST 36) on the study of brain function by PET/CT imaging

International Nuclear Information System (INIS)

Shao Guangrui; Chen Ying; Yan Bin; Liu Cheng; Wang Guangcai; Tan Qiwen

2006-01-01

Objective: To explore the correlation between acupuncture of the points and certain functional areas of brain by PET/CT imaging. Methods: Twelve healthy volunteers were acupunctured separately in the point Weizhong (BL 40, right leg) and Zusanli(ST 36, right leg), and 5 consecutive PET/CT images were taken, statistical parameter map (SPM) paired t-test was analyzed between the different activated brain PET/CT imagings. Results: Changes of PET/CT imaging were found in acupuncture of the point Weizhong (BL 40) and Zusanli(ST 36) in 12 healthy volunteers. High metabolic areas were demonstrated in multiple brain regions, the data of two groups had significant difference between 2 points (t>4.03, P< 0.01). Conclusion: Acupuncturing the different point resulted activation of the glucose metabolism in different brain areas. (authors)

PET/MR brain imaging: evaluation of clinical UTE-based attenuation correction

International Nuclear Information System (INIS)

Aasheim, Lars Birger; Karlberg, Anna; Goa, Paal Erik; Haaberg, Asta; Soerhaug, Sveinung; Fagerli, Unn-Merete; Eikenes, Live

2015-01-01

One of the greatest challenges in PET/MR imaging is that of accurate MR-based attenuation correction (AC) of the acquired PET data, which must be solved if the PET/MR modality is to reach its full potential. The aim of this study was to investigate the performance of Siemens' most recent version (VB20P) of MR-based AC of head PET data, by comparing it to CT-based AC. Methods: 18 F-FDG PET data from seven lymphoma and twelve lung cancer patients examined with a Biograph mMR PET/MR system were reconstructed with both CT-based and MR-based AC, avoiding sources of error arising when comparing PET data from different systems. The resulting images were compared quantitatively by measuring changes in mean SUV in ten different brain regions in both hemispheres, as well as the brainstem. In addition, the attenuation maps (μ maps) were compared regarding volume and localization of cranial bone. The UTE μ maps clearly overestimate the amount of bone in the neck, while slightly underestimating the amount of bone in the cranium, and the localization of bone in the cranial region also differ from the CT μ maps. In air/tissue interfaces in the sinuses and ears, the MRAC method struggles to correctly classify the different tissues. The misclassification of tissue is most likely caused by a combination of artefacts and the insufficiency of the UTE method to accurately separate bone. Quantitatively, this results in a combination of overestimation (0.5-3.6 %) and underestimation (2.7-5.2 %) of PET activity throughout the brain, depending on the proximity to the inaccurate regions. Our results indicate that the performance of the UTE method as implemented in VB20P is close to the theoretical maximum of such an MRAC method in the brain, while it does not perform satisfactorily in the neck or face/nasal area. Further improvement of the UTE MRAC or other available methods for more accurate segmentation of bone should be incorporated. (orig.)

Attenuation correction for brain PET imaging using deep neural network based on dixon and ZTE MR images.

Science.gov (United States)

Gong, Kuang; Yang, Jaewon; Kim, Kyungsang; El Fakhri, Georges; Seo, Youngho; Li, Quanzheng

2018-05-23

Positron Emission Tomography (PET) is a functional imaging modality widely used in neuroscience studies. To obtain meaningful quantitative results from PET images, attenuation correction is necessary during image reconstruction. For PET/MR hybrid systems, PET attenuation is challenging as Magnetic Resonance (MR) images do not reflect attenuation coefficients directly. To address this issue, we present deep neural network methods to derive the continuous attenuation coefficients for brain PET imaging from MR images. With only Dixon MR images as the network input, the existing U-net structure was adopted and analysis using forty patient data sets shows it is superior than other Dixon based methods. When both Dixon and zero echo time (ZTE) images are available, we have proposed a modified U-net structure, named GroupU-net, to efficiently make use of both Dixon and ZTE information through group convolution modules when the network goes deeper. Quantitative analysis based on fourteen real patient data sets demonstrates that both network approaches can perform better than the standard methods, and the proposed network structure can further reduce the PET quantification error compared to the U-net structure. © 2018 Institute of Physics and Engineering in Medicine.

Markerless 3D Head Tracking for Motion Correction in High Resolution PET Brain Imaging

DEFF Research Database (Denmark)

Olesen, Oline Vinter

relying on markers. Data-driven motion correction is problematic due to the physiological dynamics. Marker-based tracking is potentially unreliable, and it is extremely hard to validate when the tracking information is correct. The motion estimation is essential for proper motion correction of the PET......This thesis concerns application specific 3D head tracking. The purpose is to improve motion correction in position emission tomography (PET) brain imaging through development of markerless tracking. Currently, motion correction strategies are based on either the PET data itself or tracking devices...... images. Incorrect motion correction can in the worst cases result in wrong diagnosis or treatment. The evolution of a markerless custom-made structured light 3D surface tracking system is presented. The system is targeted at state-of-the-art high resolution dedicated brain PET scanners with a resolution...

Brain activation studies with PET and functional MRI

Energy Technology Data Exchange (ETDEWEB)

Yonekura, Yoshiharu [Fukui Medical Univ., Matsuoka (Japan). Biomedical Imaging Research Center; Sadato, Norihiro [Okazaki National Research Inst., Aichi (Japan). National Inst. for Physiological Sciences

2002-01-01

Application of PET and functional MRI in brain activation studies is reviewed. 3D-PET images obtained repeatedly after intravenous injection of about 370 MBq of H{sub 2}{sup 15}O can detect a faint blood flow change in the brain. Functional MRI can also detect the blood flow change in the brain due to blood oxygen level-dependent effect. Echo-planar imaging is popular in MRI with 1.5 or 3 T. Images are analyzed by statistical parametric mapping with correction of cerebral regions, anatomical normalization and statistics. PET data give the blood flow change by the H{sub 2}{sup 15}O incorporation into the brain and MRI data, by the scarce tissue oxygen consumption despite the change. Actual images during the cognition task-performance and of frequent artifacts are given. PET is suitable for studies of brain functions like sensibility and emotion and functional MRI, like cortex functions and clinical practices in identification of functional regions prior to surgery and evaluation of functional recovery of damaged brain. (K.H.)

Brain activation studies with PET and functional MRI

International Nuclear Information System (INIS)

Yonekura, Yoshiharu; Sadato, Norihiro

2002-01-01

Application of PET and functional MRI in brain activation studies is reviewed. 3D-PET images obtained repeatedly after intravenous injection of about 370 MBq of H 2 15 O can detect a faint blood flow change in the brain. Functional MRI can also detect the blood flow change in the brain due to blood oxygen level-dependent effect. Echo-planar imaging is popular in MRI with 1.5 or 3 T. Images are analyzed by statistical parametric mapping with correction of cerebral regions, anatomical normalization and statistics. PET data give the blood flow change by the H 2 15 O incorporation into the brain and MRI data, by the scarce tissue oxygen consumption despite the change. Actual images during the cognition task-performance and of frequent artifacts are given. PET is suitable for studies of brain functions like sensibility and emotion and functional MRI, like cortex functions and clinical practices in identification of functional regions prior to surgery and evaluation of functional recovery of damaged brain. (K.H.)

Evaluation of cat brain infarction model using microPET

Energy Technology Data Exchange (ETDEWEB)

Lee, J. J.; Lee, D. S.; Kim, J. H.; Hwang, D. W.; Jung, J. G.; Lee, M. C [College of Medicine, Seoul National University, Seoul (Korea, Republic of); Lim, S. M [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

2004-07-01

PET has some disadvantage in the imaging of small animal due to poor resolution. With the advance of microPET scanner, it is possible to image small animals. However, the image quality was not so much satisfactory as human image. As cats have relatively large sized brain, cat brain imaging was superior to mice or rat. In this study, we established the cat brain infarction model and evaluate it and its temporal change using microPET scanner. Two adult male cats were used. Anesthesia was done with xylazine and ketamine HCl. A burr hole was made at 1cm right lateral to the bregma. Collagenase type IV 10 ul was injected using 30G needle for 5 minutes to establish the infarction model. F-18 FDG microPET (Concorde Microsystems Inc., Knoxville. TN) scans were performed 1. 11 and 32 days after the infarction. In addition. 18F-FDG PET scans were performed using Gemini PET scanner (Philips medical systems. CA, USA) 13 and 47 days after the infarction. Two cat brain infarction models were established. The glucose metabolism of an infraction lesion improved with time. An infarction lesion was also distinguishable in the Gemini PET scan. We successfully established the cat brain infarction model and evaluated the infarcted lesion and its temporal change using F-18 FDG microPET scanner.

Evaluation of cat brain infarction model using microPET

Energy Technology Data Exchange (ETDEWEB)

Lee, Jong Jin; Lee, Dong Soo; Kim, Yun Hui; Hwang, Do Won; Kim, Jin Su; Chung, June Key; Lee, Myung Chul [College of Medicine, Seoul National Univ., Seoul (Korea, Republic of); Lim, Sang Moo [Korea Institite of Radiological and Medical Sciences, Seoul (Korea, Republic of)

2004-12-01

PET has some disadvantage in the imaging of small animal due to poor resolution. With the advent of microPET scanner, it is possible to image small animals. However, the image quality was not good enough as human image. Due to larger brain, cat brain imaging was superior to mouse or rat. In this study, we established the cat brain infarction model and evaluate it and its temporal change using microPET scanner. Two adult male cats were used. Anesthesia was done with xylazine and ketamine HCI. A burr hole was made at 1 cm right lateral to the bregma. Collagenase type IV 10 {mu}l was injected using 30 G needle for 5 minutes to establish the infarction model. {sup 18}F-FDG microPET (Concorde Microsystems Inc., Knoxville, TN) scans were performed 1, 11 and 32 days after the infarction. In addition, {sup 18}F-FDG PET scans were performed using human PET scanner (Gemini, Philips medical systems, CA, USA) 13 and 47 days after the infarction. Two cat brain infarction models were established. The glucose metabolism of an infarction lesion improved with time. An infarction lesion was also distinguishable in the human PET scan. We successfully established the cat brain infarction model and evaluated the infarcted lesion and its temporal change using {sup 18}F-FDG microPET scanner.

Evaluation of cat brain infarction model using microPET

International Nuclear Information System (INIS)

Lee, J. J.; Lee, D. S.; Kim, J. H.; Hwang, D. W.; Jung, J. G.; Lee, M. C; Lim, S. M

2004-01-01

PET has some disadvantage in the imaging of small animal due to poor resolution. With the advance of microPET scanner, it is possible to image small animals. However, the image quality was not so much satisfactory as human image. As cats have relatively large sized brain, cat brain imaging was superior to mice or rat. In this study, we established the cat brain infarction model and evaluate it and its temporal change using microPET scanner. Two adult male cats were used. Anesthesia was done with xylazine and ketamine HCl. A burr hole was made at 1cm right lateral to the bregma. Collagenase type IV 10 ul was injected using 30G needle for 5 minutes to establish the infarction model. F-18 FDG microPET (Concorde Microsystems Inc., Knoxville. TN) scans were performed 1. 11 and 32 days after the infarction. In addition. 18F-FDG PET scans were performed using Gemini PET scanner (Philips medical systems. CA, USA) 13 and 47 days after the infarction. Two cat brain infarction models were established. The glucose metabolism of an infraction lesion improved with time. An infarction lesion was also distinguishable in the Gemini PET scan. We successfully established the cat brain infarction model and evaluated the infarcted lesion and its temporal change using F-18 FDG microPET scanner

Evaluation of cat brain infarction model using microPET

International Nuclear Information System (INIS)

Lee, Jong Jin; Lee, Dong Soo; Kim, Yun Hui; Hwang, Do Won; Kim, Jin Su; Chung, June Key; Lee, Myung Chul; Lim, Sang Moo

2004-01-01

PET has some disadvantage in the imaging of small animal due to poor resolution. With the advent of microPET scanner, it is possible to image small animals. However, the image quality was not good enough as human image. Due to larger brain, cat brain imaging was superior to mouse or rat. In this study, we established the cat brain infarction model and evaluate it and its temporal change using microPET scanner. Two adult male cats were used. Anesthesia was done with xylazine and ketamine HCI. A burr hole was made at 1 cm right lateral to the bregma. Collagenase type IV 10 μl was injected using 30 G needle for 5 minutes to establish the infarction model. 18 F-FDG microPET (Concorde Microsystems Inc., Knoxville, TN) scans were performed 1, 11 and 32 days after the infarction. In addition, 18 F-FDG PET scans were performed using human PET scanner (Gemini, Philips medical systems, CA, USA) 13 and 47 days after the infarction. Two cat brain infarction models were established. The glucose metabolism of an infarction lesion improved with time. An infarction lesion was also distinguishable in the human PET scan. We successfully established the cat brain infarction model and evaluated the infarcted lesion and its temporal change using 18 F-FDG microPET scanner

Attenuation correction for the large non-human primate brain imaging using microPET

International Nuclear Information System (INIS)

Naidoo-Variawa, S; Lehnert, W; Kassiou, M; Banati, R; Meikle, S R

2010-01-01

Assessment of the biodistribution and pharmacokinetics of radiopharmaceuticals in vivo is often performed on animal models of human disease prior to their use in humans. The baboon brain is physiologically and neuro-anatomically similar to the human brain and is therefore a suitable model for evaluating novel CNS radioligands. We previously demonstrated the feasibility of performing baboon brain imaging on a dedicated small animal PET scanner provided that the data are accurately corrected for degrading physical effects such as photon attenuation in the body. In this study, we investigated factors affecting the accuracy and reliability of alternative attenuation correction strategies when imaging the brain of a large non-human primate (papio hamadryas) using the microPET Focus 220 animal scanner. For measured attenuation correction, the best bias versus noise performance was achieved using a 57 Co transmission point source with a 4% energy window. The optimal energy window for a 68 Ge transmission source operating in singles acquisition mode was 20%, independent of the source strength, providing bias-noise performance almost as good as for 57 Co. For both transmission sources, doubling the acquisition time had minimal impact on the bias-noise trade-off for corrected emission images, despite observable improvements in reconstructed attenuation values. In a [ 18 F]FDG brain scan of a female baboon, both measured attenuation correction strategies achieved good results and similar SNR, while segmented attenuation correction (based on uncorrected emission images) resulted in appreciable regional bias in deep grey matter structures and the skull. We conclude that measured attenuation correction using a single pass 57 Co (4% energy window) or 68 Ge (20% window) transmission scan achieves an excellent trade-off between bias and propagation of noise when imaging the large non-human primate brain with a microPET scanner.

Hybrid MR-PET of brain tumours using amino acid PET and chemical exchange saturation transfer MRI.

Science.gov (United States)

da Silva, N A; Lohmann, P; Fairney, J; Magill, A W; Oros Peusquens, A-M; Choi, C-H; Stirnberg, R; Stoffels, G; Galldiks, N; Golay, X; Langen, K-J; Jon Shah, N

2018-06-01

PET using radiolabelled amino acids has become a promising tool in the diagnostics of gliomas and brain metastasis. Current research is focused on the evaluation of amide proton transfer (APT) chemical exchange saturation transfer (CEST) MR imaging for brain tumour imaging. In this hybrid MR-PET study, brain tumours were compared using 3D data derived from APT-CEST MRI and amino acid PET using O-(2- 18 F-fluoroethyl)-L-tyrosine ( 18 F-FET). Eight patients with gliomas were investigated simultaneously with 18 F-FET PET and APT-CEST MRI using a 3-T MR-BrainPET scanner. CEST imaging was based on a steady-state approach using a B 1 average power of 1μT. B 0 field inhomogeneities were corrected a Prametric images of magnetisation transfer ratio asymmetry (MTR asym ) and differences to the extrapolated semi-solid magnetisation transfer reference method, APT# and nuclear Overhauser effect (NOE#), were calculated. Statistical analysis of the tumour-to-brain ratio of the CEST data was performed against PET data using the non-parametric Wilcoxon test. A tumour-to-brain ratio derived from APT# and 18 F-FET presented no significant differences, and no correlation was found between APT# and 18 F-FET PET data. The distance between local hot spot APT# and 18 F-FET were different (average 20 ± 13 mm, range 4-45 mm). For the first time, CEST images were compared with 18 F-FET in a simultaneous MR-PET measurement. Imaging findings derived from 18 F-FET PET and APT CEST MRI seem to provide different biological information. The validation of these imaging findings by histological confirmation is necessary, ideally using stereotactic biopsy.

Automatic extraction analysis of the anatomical functional area for normal brain 18F-FDG PET imaging

International Nuclear Information System (INIS)

Guo Wanhua; Jiang Xufeng; Zhang Liying; Lu Zhongwei; Li Peiyong; Zhu Chengmo; Zhang Jiange; Pan Jiapu

2003-01-01

Using self-designed automatic extraction software of brain functional area, the grey scale distribution of 18 F-FDG imaging and the relationship between the 18 F-FDG accumulation of brain anatomic function area and the 18 F-FDG injected dose, the level of glucose, the age, etc., were studied. According to the Talairach coordinate system, after rotation, drift and plastic deformation, the 18 F-FDG PET imaging was registered into the Talairach coordinate atlas, and then the average gray value scale ratios between individual brain anatomic functional area and whole brain area was calculated. Further more the statistics of the relationship between the 18 F-FDG accumulation of every brain anatomic function area and the 18 F-FDG injected dose, the level of glucose and the age were tested by using multiple stepwise regression model. After images' registration, smoothing and extraction, main cerebral cortex of the 18 F-FDG PET brain imaging can be successfully localized and extracted, such as frontal lobe, parietal lobe, occipital lobe, temporal lobe, cerebellum, brain ventricle, thalamus and hippocampus. The average ratios to the inner reference of every brain anatomic functional area were 1.01 ± 0.15. By multiple stepwise regression with the exception of thalamus and hippocampus, the grey scale of all the brain functional area was negatively correlated to the ages, but with no correlation to blood sugar and dose in all areas. To the 18 F-FDG PET imaging, the brain functional area extraction program could automatically delineate most of the cerebral cortical area, and also successfully reflect the brain blood and metabolic study, but extraction of the more detailed area needs further investigation

Automatic Thresholding for Frame-Repositioning Using External Tracking in PET Brain Imaging

DEFF Research Database (Denmark)

Olesen, Oline Vinter; Keller, Sune; Sibomana, Merence

2010-01-01

Motion correction (MC) in positron emission tomography (PET) brain imaging become of higher importance with increasing scanner resolution. Several motion correction methods have been suggested and so far the Polaris Vicra tracking system has been the preferred one for motion registration. We...... present an automated algorithm for dividing PET acquisitions into subframes based on the registered head motion to correct for intra-frame motion with the frame repositioning MC method. The method is tested on real patient data (five 11C-SB studies and five 11C-PIB studies) and compared with an image...... based registration method (AIR). Quantitative evaluation was done using a correlation measure. The study shows that MC improves the correlation of the PET images and that AIR performed slightly better than the Polaris Vicra. We found significant intra-frame motion of 1-5 mm in 9 frames...

Brain tumour imaging with PET: a comparison between [{sup 18}F]fluorodopa and [{sup 11}C]methionine

Energy Technology Data Exchange (ETDEWEB)

Becherer, Alexander; Karanikas, Georgios; Szabo, Monica; Zettinig, Georg; Wadsak, Wolfgang; Kletter, Kurt [Department of Nuclear Medicine, Medical School, University of Vienna, Waehringer Guertel 18-20, 1090, Vienna (Austria); Asenbaum, Susanne [Department of Neurology, Medical School, University of Vienna, Vienna (Austria); Marosi, Christine [Department of Oncology, Medical School, University of Vienna, Vienna (Austria); Henk, Christine; Wunderbaldinger, Patrick [Department of Radiology, Medical School, University of Vienna, Vienna (Austria); Czech, Thomas [Department of Neurosurgery, Medical School, University of Vienna, Vienna (Austria)

2003-11-01

Imaging of amino acid transport in brain tumours is more sensitive than fluorine-18 2-fluoro-deoxyglucose positron emission tomography (PET). The most frequently used tracer in this field is carbon-11 methionine (MET), which is unavailable for PET centres without a cyclotron because of its short half-life. The purpose of this study was to evaluate the performance of 3,4-dihydroxy-6-[{sup 18}F]fluoro-phenylalanine (FDOPA) in this setting, in comparison with MET. Twenty patients with known supratentorial brain lesions were referred for PET scans with FDOPA and MET. The diagnoses were 18 primary brain tumours, one metastasis and one non-neoplastic cerebral lesion. All 20 patients underwent PET with FDOPA (100 MBq, 20 min p.i.), and 19 of them also had PET scans with MET (800 MBq, 20 min p.i.). In all but one patient a histological diagnosis was available. In 15 subjects, histology was known from previous surgical interventions; in five of these patients, as well as in four previously untreated patients, histology was obtained after PET. In one untreated patient, confirmation of PET was possible solely by correlation with MRI; a histological diagnosis became available 10 months later. MET and FDOPA images matched in all patients and showed all lesions as hot spots with higher uptake than in the contralateral brain. Standardised uptake value ratios, tumour/contralateral side (mean{+-}SD), were 2.05{+-}0.91 for MET and 2.04{+-}0.53 for FDOPA (NS). The benign lesion, which biopsy revealed to be a focal demyelination, was false positive, showing increased uptake of MET and FDOPA. We conclude that FDOPA is accurate as a surrogate for MET in imaging amino acid transport in malignant cerebral lesions for the purpose of visualisation of vital tumour tissue. It combines the good physical properties of {sup 18}F with the pharmacological properties of MET and might therefore be a valuable PET radiopharmaceutical in brain tumour imaging. (orig.)

Quantitative estimation of brain atrophy and function with PET and MRI two-dimensional projection images

International Nuclear Information System (INIS)

Saito, Reiko; Uemura, Koji; Uchiyama, Akihiko; Toyama, Hinako; Ishii, Kenji; Senda, Michio

2001-01-01

The purpose of this paper is to estimate the extent of atrophy and the decline in brain function objectively and quantitatively. Two-dimensional (2D) projection images of three-dimensional (3D) transaxial images of positron emission tomography (PET) and magnetic resonance imaging (MRI) were made by means of the Mollweide method which keeps the area of the brain surface. A correlation image was generated between 2D projection images of MRI and cerebral blood flow (CBF) or 18 F-fluorodeoxyglucose (FDG) PET images and the sulcus was extracted from the correlation image clustered by K-means method. Furthermore, the extent of atrophy was evaluated from the extracted sulcus on 2D-projection MRI and the cerebral cortical function such as blood flow or glucose metabolic rate was assessed in the cortex excluding sulcus on 2D-projection PET image, and then the relationship between the cerebral atrophy and function was evaluated. This method was applied to the two groups, the young and the aged normal subjects, and the relationship between the age and the rate of atrophy or the cerebral blood flow was investigated. This method was also applied to FDG-PET and MRI studies in the normal controls and in patients with corticobasal degeneration. The mean rate of atrophy in the aged group was found to be higher than that in the young. The mean value and the variance of the cerebral blood flow for the young are greater than those of the aged. The sulci were similarly extracted using either CBF or FDG PET images. The purposed method using 2-D projection images of MRI and PET is clinically useful for quantitative assessment of atrophic change and functional disorder of cerebral cortex. (author)

Pet Imaging Of The Chemistry Of The Brain

Science.gov (United States)

Wagner, Henry N., Jr.

1986-06-01

Advances in neurobiology today are as important as the advances in atomic physics at the turn of the century and molecular genetics in the 1950's. Positron-emission tomography is participating in these advances by making it possible for the first time to measure the chemistry of the living human brain in health and disease and to relate the changes at the molecular level to the functioning of the human mind. The amount of data generated requires modern data processing, display, and archiving capabilities. To achieve maximum benefit from the PET imaging and the derived quantitative measurements, the data must be combined with information, usually of a structural nature, from other imaging modalities, chiefly computed tomography and magnetic resonance imaging.

Adapting MR-BrainPET scans for comparison with conventional PET: experiences with dynamic FET-PET in brain tumours

Energy Technology Data Exchange (ETDEWEB)

Lohmann, Philipp; Herzog, Hans; Kops, Elena Rota; Stoffels, Gabriele; Filss, Christian [Institute of Neuroscience and Medicine (INM-3,-4,-5), Forschungszentrum Juelich, Juelich (Germany); Galldiks, Norbert [Institute of Neuroscience and Medicine (INM-3,-4,-5), Forschungszentrum Juelich, Juelich (Germany); Department of Neurology, University of Cologne, Cologne (Germany); Coenen, Heinrich H; Shah, N Jon; Langen, Karl-Josef [Institute of Neuroscience and Medicine (INM-3,-4,-5), Forschungszentrum Juelich, Juelich (Germany)

2014-07-29

Imaging results from subsequent measurements (preclinical 3T MR-BrainPET, HR+) are compared. O-(2-[{sup 18}F]fluoroethyl)-L-tyrosine (FET) may exhibit non-uniform tracer uptake in gliomas. The aim was to analyse and adapt the physical properties of the scanners and study variations of biological tumour volume (BTV) in early and late FET-PET.

PET imaging reveals brain functional changes in internet gaming disorder

International Nuclear Information System (INIS)

Tian, Mei; Zhang, Ying; Du, Fenglei; Hou, Haifeng; Chao, Fangfang; Zhang, Hong; Chen, Qiaozhen

2014-01-01

Internet gaming disorder is an increasing problem worldwide, resulting in critical academic, social, and occupational impairment. However, the neurobiological mechanism of internet gaming disorder remains unknown. The aim of this study is to assess brain dopamine D 2 (D 2 )/Serotonin 2A (5-HT 2A ) receptor function and glucose metabolism in the same subjects by positron emission tomography (PET) imaging approach, and investigate whether the correlation exists between D 2 receptor and glucose metabolism. Twelve drug-naive adult males who met criteria for internet gaming disorder and 14 matched controls were studied with PET and 11 C-N-methylspiperone ( 11 C-NMSP) to assess the availability of D 2 /5-HT 2A receptors and with 18 F-fluoro-D-glucose ( 18 F-FDG) to assess regional brain glucose metabolism, a marker of brain function. 11 C-NMSP and 18 F-FDG PET imaging data were acquired in the same individuals under both resting and internet gaming task states. In internet gaming disorder subjects, a significant decrease in glucose metabolism was observed in the prefrontal, temporal, and limbic systems. Dysregulation of D 2 receptors was observed in the striatum, and was correlated to years of overuse. A low level of D 2 receptors in the striatum was significantly associated with decreased glucose metabolism in the orbitofrontal cortex. For the first time, we report the evidence that D 2 receptor level is significantly associated with glucose metabolism in the same individuals with internet gaming disorder, which indicates that D 2 /5-HT 2A receptor-mediated dysregulation of the orbitofrontal cortex could underlie a mechanism for loss of control and compulsive behavior in internet gaming disorder subjects. (orig.)

Image-derived input function obtained in a 3TMR-brainPET

Energy Technology Data Exchange (ETDEWEB)

Silva, N.A. da [Institute of Biophysics and Biomedical Engineering, University of Lisbon (Portugal); Institute of Neurosciences and Medicine - 4, Juelich (Germany); Herzog, H., E-mail: h.herzog@fz-juelich.de [Institute of Neurosciences and Medicine - 4, Juelich (Germany); Weirich, C.; Tellmann, L.; Rota Kops, E. [Institute of Neurosciences and Medicine - 4, Juelich (Germany); Hautzel, H. [Department of Nuclear Medicine (KME), University of Duesseldorf, Medical Faculty at Research Center Juelich, Juelich (Germany); Almeida, P. [Institute of Biophysics and Biomedical Engineering, University of Lisbon (Portugal)

2013-02-21

Aim: The combination of a high-resolution MR-compatible BrainPET insert operated within a 3 T MAGNETOM Trio MR scanner is an excellent tool for obtaining an image derived input function (IDIF), due to simultaneous imaging. In this work, we explore the possibility of obtaining an IDIF from volumes of interest (VOI) defined over the carotid arteries (CAs) using the MR data. Material and methods: FDG data from three patients without brain disorders were included. VOIs were drawn bilaterally over the CAs on a MPRAGE image using a 50% isocontour (MR50VOI). CA PET/MR co-registration was examined based on an individual and combined CA co-registration. After that, to estimate the IDIF, the MR50VOI average (IDIF-A), four hottest pixels per plane (IDIF-4H) and four hottest pixels in VOI (IDIF-4V) were considered. A model-based correction for residual partial volume effects involving venous blood samples was applied, from which partial volume (PV) and spillover (SP) coefficients were estimated. Additionally, a theoretical PV coefficient (PVt) was calculated based on MR50VOI. Results: The results show an excellent co-registration between the MR and PET, with an area under the curve ratio between both co-registration methods of 1.00±0.04. A good agreement between PV and PVt was found for IDIF-A, with PV of 0.39±0.06 and PVt 0.40±0.03, and for IDIF-4H, with PV of 0.47±0.05 and PVt 0.47±0.03. The SPs were 0.20±0.03 and 0.21±0.03 for IDIF-A and IDIF-4H, respectively. Conclusion: The integration of a high resolution BrainPET in an MR scanner allows to obtain an IDIF from an MR-based VOI. This must be corrected for a residual partial volume effect.

Imaging for metabotropic glutamate receptor subtype 1 in rat and monkey brains using PET with [18F]FITM.

Science.gov (United States)

Yamasaki, Tomoteru; Fujinaga, Masayuki; Maeda, Jun; Kawamura, Kazunori; Yui, Joji; Hatori, Akiko; Yoshida, Yuichiro; Nagai, Yuji; Tokunaga, Masaki; Higuchi, Makoto; Suhara, Tetsuya; Fukumura, Toshimitsu; Zhang, Ming-Rong

2012-04-01

In this study, we evaluate the utility of 4-[(18)F]fluoro-N-[4-[6-(isopropylamino)pyrimidin-4-yl]-1,3-thiazol-2-yl]-N-methylbenzamide ([(18)F]FITM) as a positron emission tomography (PET) ligand for imaging of the metabotropic glutamate receptor subtype 1 (mGluR1) in rat and monkey brains. In vivo distribution of [(18)F]FITM in brains was evaluated by PET scans with or without the mGluR1-selective antagonist (JNJ16259685). Kinetic parameters of monkey PET data were obtained using the two-tissue compartment model with arterial blood sampling. In PET studies in rat and monkey brains, the highest uptake of radioactivity was in the cerebellum, followed by moderate uptake in the thalamus, hippocampus and striatum. The lowest uptake of radioactivity was detected in the pons. These uptakes in all brain regions were dramatically decreased by pre-administration of JNJ16259685. In kinetic analysis of monkey PET, the highest volume of distribution (V(T)) was detected in the cerebellum (V(T) = 11.5). [(18)F]FITM has an excellent profile as a PET ligand for mGluR1 imaging. PET with [(18)F]FITM may prove useful for determining the regional distribution and density of mGluR1 and the mGluR1 occupancy of drugs in human brains.

Comparative studies of '18F-FDG PET/CT brain imaging and EEG in preoperative localization of temporal lobe epileptic focus

International Nuclear Information System (INIS)

Chen Ziqian; Zhao Chunlei; Liu Yao; Ni Ping; Zhong Qun; Bai Wei; Peng Dexin

2012-01-01

Objective: To compare the value of 18 F-FDG PET/CT brain imaging and EEG in preoperative localization of the epileptic focus at the temporal lobe. Methods: A total of 152 patients (108 males, 44 females, age ranged from 3 to 59 years old) with past history of temporal lobe epilepsy were included.All patients underwent 18 F-FDG PET/CT brain imaging and long-range or video EEG, and 29 patients underwent intracranial electrode EEG due to the failure to localize the disease focus by non-invasive methods.Histopathologic findings after operative treatment were considered the gold standard for disease localization. All patients were followed up for at least six months after the operation. The accuracy of the 18 F-FDG PET/CT brain imaging and long-range or video EEG examination were compared using χ 2 test. Results: The accuracy of locating the epileptic focus was 80.92% (123/152) for 18 F-FDG PET/CT brain imaging and 43.42% (66/152) for long-range or video EEG (χ 2 =22.72, P<0.01). The accuracy of locating the epileptic focus for the 29 cases with intracranial electrode EEG was 100%. Conclusions: Interictal 18 F-FDG PET/CT brain imaging is a sensitive and effective method to locate the temporal lobe epileptic focus and is better than long-range or video EEG. The combination of 18 F-FDG PET/CT brain imaging and intracranial electrode EEG examination can further improve the accuracy of locating the epileptic focus. (authors)

DELAYED FDG-PET/CT IMAGES IN PATIENTS WITH BRAIN TUMORS - IMPACT ON VISUAL AND SEMIQUANTITATIVE ASSESSMENT

Directory of Open Access Journals (Sweden)

Pavel H. Bochev

2013-01-01

Full Text Available Background: Despite the extensive use of FDG-PET/CT its role in brain tumor assessment remains controversial mostly because of the physiologically high brain uptake which easily obscures pathological processes. The wide availability of FDG, however, maintains the interest in FDG neuro-oncological applications. Objective: to evaluate the use of a late registration at 180min in patients with brain tumors, studied with FDG-PET/CT based on visual and semiquantitative analysis. Materials and methods: 38 patients with brain neoplasms and non-tumor structural lesions underwent a selective brain 18F-FDG PET/CT at two time points at 60 and 180 minutes after administration. Visual assessment was made by two readers with interobserver agreement calculation. Region ratio comparison with three different reference regions - the contralateral one, the white matter, and the cerebellum was used as a base for semiquantitative analysis. Results: Visual analysis showed better delineation of malignant lesion on late registrations with higher inter/intraobserver agreement as compared to the early images. Semiquantitative analysis demonstrated significant differences in early and late indices of metastases and gliomas, but failed in distinguishing gliomas from metastatic lesions and benign lesions.Conclusion: Delayed brain images with FDG-PET/CT at 180 min after injection provide better tumor delineation, higher accuracy, lower interobserver variations. The use of semiquantitative indices, irrespective of the reference region used, is of limited value

Disease progression in AIDS on PET fluorodeoxyglucose, CT and MR brain images

International Nuclear Information System (INIS)

Verma, R.C.; Bennett, L.; Gan, M.; Kloumehr, F.; Mathisen, G.; Jones, F.D.; Wasterlain, C.; Mandelkern, M.; Ropchan, J.; Blahd, W.; Yaghmal, I.

1990-01-01

This paper correlates changes in the brain demonstrated on F-18 fluorodeoxyglucose (FDG) positron emission tomographic (PET) scans and CT or MR images with disease severity in patients with acquired immunodeficiency syndrome (AIDS). Data from 30 patients who tested positive for human immunodeficiency virus (HIV) who were at various stages of AIDS, and who had undergone FDG PET, CT, and/or MR imaging were reviewed retrospectively. The average CD4 lymphocyte counts, an indicator of disease severity in AIDS, in 25 symptomatic (group I) and five healthy seropositive (group II) subjects were 300 and 694 cells/mm 3 , respectively. Cortical atrophy was present on CT and/or MR imaging in 92% in group I and only 20% in group II. Of the 17 patients in group I who underwent PET scans 11 demonstrated an elevated basal ganglia to frontal cortex (BG/FC) ratio of FDG uptake; only one of the four in group II had this finding

High-resolution imaging of the large non-human primate brain using microPET: a feasibility study

Science.gov (United States)

Naidoo-Variawa, S.; Hey-Cunningham, A. J.; Lehnert, W.; Kench, P. L.; Kassiou, M.; Banati, R.; Meikle, S. R.

2007-11-01

The neuroanatomy and physiology of the baboon brain closely resembles that of the human brain and is well suited for evaluating promising new radioligands in non-human primates by PET and SPECT prior to their use in humans. These studies are commonly performed on clinical scanners with 5 mm spatial resolution at best, resulting in sub-optimal images for quantitative analysis. This study assessed the feasibility of using a microPET animal scanner to image the brains of large non-human primates, i.e. papio hamadryas (baboon) at high resolution. Factors affecting image accuracy, including scatter, attenuation and spatial resolution, were measured under conditions approximating a baboon brain and using different reconstruction strategies. Scatter fraction measured 32% at the centre of a 10 cm diameter phantom. Scatter correction increased image contrast by up to 21% but reduced the signal-to-noise ratio. Volume resolution was superior and more uniform using maximum a posteriori (MAP) reconstructed images (3.2-3.6 mm3 FWHM from centre to 4 cm offset) compared to both 3D ordered subsets expectation maximization (OSEM) (5.6-8.3 mm3) and 3D reprojection (3DRP) (5.9-9.1 mm3). A pilot 18F-2-fluoro-2-deoxy-d-glucose ([18F]FDG) scan was performed on a healthy female adult baboon. The pilot study demonstrated the ability to adequately resolve cortical and sub-cortical grey matter structures in the baboon brain and improved contrast when images were corrected for attenuation and scatter and reconstructed by MAP. We conclude that high resolution imaging of the baboon brain with microPET is feasible with appropriate choices of reconstruction strategy and corrections for degrading physical effects. Further work to develop suitable correction algorithms for high-resolution large primate imaging is warranted.

High-resolution imaging of the large non-human primate brain using microPET: a feasibility study

Energy Technology Data Exchange (ETDEWEB)

Naidoo-Variawa, S [Discipline of Medical Radiation Sciences, Faculty of Health Sciences, University of Sydney, PO Box 170, Lidcombe, NSW 1825, Sydney (Australia); Hey-Cunningham, A J [Discipline of Medical Radiation Sciences, Faculty of Health Sciences, University of Sydney, PO Box 170, Lidcombe, NSW 1825, Sydney (Australia); Lehnert, W [Discipline of Medical Radiation Sciences, Faculty of Health Sciences, University of Sydney, PO Box 170, Lidcombe, NSW 1825, Sydney (Australia); Kench, P L [Discipline of Medical Radiation Sciences, Faculty of Health Sciences, University of Sydney, PO Box 170, Lidcombe, NSW 1825, Sydney (Australia); Kassiou, M [Discipline of Medical Radiation Sciences, Faculty of Health Sciences, University of Sydney, PO Box 170, Lidcombe, NSW 1825, Sydney (Australia); Banati, R [Discipline of Medical Radiation Sciences, Faculty of Health Sciences, University of Sydney, PO Box 170, Lidcombe, NSW 1825, Sydney (Australia); Meikle, S R [Discipline of Medical Radiation Sciences, Faculty of Health Sciences, University of Sydney, PO Box 170, Lidcombe, NSW 1825, Sydney (Australia)

2007-11-21

The neuroanatomy and physiology of the baboon brain closely resembles that of the human brain and is well suited for evaluating promising new radioligands in non-human primates by PET and SPECT prior to their use in humans. These studies are commonly performed on clinical scanners with 5 mm spatial resolution at best, resulting in sub-optimal images for quantitative analysis. This study assessed the feasibility of using a microPET animal scanner to image the brains of large non-human primates, i.e. papio hamadryas (baboon) at high resolution. Factors affecting image accuracy, including scatter, attenuation and spatial resolution, were measured under conditions approximating a baboon brain and using different reconstruction strategies. Scatter fraction measured 32% at the centre of a 10 cm diameter phantom. Scatter correction increased image contrast by up to 21% but reduced the signal-to-noise ratio. Volume resolution was superior and more uniform using maximum a posteriori (MAP) reconstructed images (3.2-3.6 mm{sup 3} FWHM from centre to 4 cm offset) compared to both 3D ordered subsets expectation maximization (OSEM) (5.6-8.3 mm{sup 3}) and 3D reprojection (3DRP) (5.9-9.1 mm{sup 3}). A pilot {sup 18}F-2-fluoro-2-deoxy-d-glucose ([{sup 18}F]FDG) scan was performed on a healthy female adult baboon. The pilot study demonstrated the ability to adequately resolve cortical and sub-cortical grey matter structures in the baboon brain and improved contrast when images were corrected for attenuation and scatter and reconstructed by MAP. We conclude that high resolution imaging of the baboon brain with microPET is feasible with appropriate choices of reconstruction strategy and corrections for degrading physical effects. Further work to develop suitable correction algorithms for high-resolution large primate imaging is warranted.

PET imaging of neuroinflammation in a rat traumatic brain injury model with radiolabeled TSPO ligand DPA-714

Energy Technology Data Exchange (ETDEWEB)

Wang, Yu [Medical School of Southeast University, Jiangsu Key Laboratory of Molecular Imaging and Functional Imaging, Department of Radiology, Zhongda Hospital, Nanjing (China); National Institutes of Health - NIH, Laboratory of Molecular Imaging and Nanomedicine - LOMIN, National Institute of Biomedical Imaging and Bioengineering - NIBIB, Bethesda, MD (United States); Yue, Xuyi; Kiesewetter, Dale O.; Niu, Gang; Chen, Xiaoyuan [National Institutes of Health - NIH, Laboratory of Molecular Imaging and Nanomedicine - LOMIN, National Institute of Biomedical Imaging and Bioengineering - NIBIB, Bethesda, MD (United States); Teng, Gaojun [Medical School of Southeast University, Jiangsu Key Laboratory of Molecular Imaging and Functional Imaging, Department of Radiology, Zhongda Hospital, Nanjing (China)

2014-07-15

The inflammatory response in injured brain parenchyma after traumatic brain injury (TBI) is crucial in the pathological process. In order to follow microglia activation and neuroinflammation after TBI, we performed PET imaging in a rat model of TBI using {sup 18}F-labeled DPA-714, a ligand of the 18-kDa translocator protein (TSPO). TBI was induced in male SD rats by a controlled cortical impact. The success of the TBI model was confirmed by MRI. [{sup 18}F]DPA-714 was synthesized using a slightly modified TRACERLab FX-FN module and an automated procedure. In vivo PET imaging was performed at different time points after surgery using an Inveon small-animal PET scanner. The specificity of [{sup 18}F]DPA-714 was confirmed by a displacement study with an unlabeled competitive TSPO ligand, PK11195. Ex vivo autoradiography as well as immunofluorescence staining was carried out to confirm the in vivo PET results. Both in vivo T{sub 2}-weighted MR images and ex vivo TTC staining results revealed successful establishment of the TBI model. Compared with the sham-treated group, [{sup 18}F]DPA-714 uptake was significantly higher in the injured brain area on PET images. Increased lesion-to-normal ratios of [{sup 18}F]DPA-714 were observed in the brain of TBI rats on day 2 after surgery. Ratios peaked around day 6 (2.65 ± 0.36) and then decreased gradually to nearly normal levels on day 28. The displacement study using PK11195 confirmed the specific binding of [{sup 18}F]DPA-714 to TSPO. The results of ex vivo autoradiography were consistent with in vivo PET results. Immunofluorescence staining showed the time course of TSPO expression after TBI and the temporal and the spatial distribution of microglia in the damaged brain area. TSPO-targeted PET using [{sup 18}F]DPA-714 as the imaging probe can be used to dynamically monitor the inflammatory response after TBI in a noninvasive manner. This method will not only facilitate a better understanding of the inflammatory process

Clinical evaluation of PET image quality as a function of acquisition time in a new TOF-PET/MR compared to TOF-PET/CT - initial results

International Nuclear Information System (INIS)

Zeimpekis, Konstantinos; Huellner, Martin; De Galiza Barbosa, Felipe; Ter Voert, Edwin; Davison, Helen; Delso, Gaspar; Veit-Haibach, Patrick

2015-01-01

The recently available integrated PET/MR imaging can offer significant additional advances in clinical imaging. The purpose of this study was to compare the PET performance between a PET/CT scanner and an integrated TOF-PET/MR scanner concerning image quality parameters and quantification in terms of SUV as a function of acquisition time (a surrogate of dose). Five brain and five whole body patients were included in the study. The PET/CT scan was used as a reference and the PET/MR acquisition time was consecutively adjusted, taking into account the decay between the scans in order to expose both systems to the same amount of emitted signal. The acquisition times were then retrospectively reduced to assess the performance of the PET/MRI for lower count rates. Image quality, image sharpness, artifacts and noise were evaluated. SUV measurements were taken in the liver and in white matter to compare quantification. Quantitative evaluation showed good correlation between PET/CT and PET/MR brain SUVs. Liver correlation was lower, with uptake underestimation in PET/MR, partially justified by bio-redistribution. The clinical evaluation showed that PET/MR offers higher image quality and sharpness with lower levels of noise and artefacts compared to PET/CT with reduced acquisition times for whole body scans, while for brain scans there is no significant difference. The PET-component of the TOF-PET/MR showed higher image quality compared to PET/CT as tested with reduced imaging times. However, these results account mainly for body imaging, while no significant difference were found in brain imaging. This overall higher image quality suggests that the acquisition time or injected activity can be reduced by at least 37% on the PET/MR scanner.

Clinical evaluation of PET image quality as a function of acquisition time in a new TOF-PET/MR compared to TOF-PET/CT - initial results

Energy Technology Data Exchange (ETDEWEB)

Zeimpekis, Konstantinos; Huellner, Martin; De Galiza Barbosa, Felipe; Ter Voert, Edwin; Davison, Helen; Delso, Gaspar; Veit-Haibach, Patrick [Nuclear Medicine, University Hospital Zurich (Switzerland)

2015-05-18

The recently available integrated PET/MR imaging can offer significant additional advances in clinical imaging. The purpose of this study was to compare the PET performance between a PET/CT scanner and an integrated TOF-PET/MR scanner concerning image quality parameters and quantification in terms of SUV as a function of acquisition time (a surrogate of dose). Five brain and five whole body patients were included in the study. The PET/CT scan was used as a reference and the PET/MR acquisition time was consecutively adjusted, taking into account the decay between the scans in order to expose both systems to the same amount of emitted signal. The acquisition times were then retrospectively reduced to assess the performance of the PET/MRI for lower count rates. Image quality, image sharpness, artifacts and noise were evaluated. SUV measurements were taken in the liver and in white matter to compare quantification. Quantitative evaluation showed good correlation between PET/CT and PET/MR brain SUVs. Liver correlation was lower, with uptake underestimation in PET/MR, partially justified by bio-redistribution. The clinical evaluation showed that PET/MR offers higher image quality and sharpness with lower levels of noise and artefacts compared to PET/CT with reduced acquisition times for whole body scans, while for brain scans there is no significant difference. The PET-component of the TOF-PET/MR showed higher image quality compared to PET/CT as tested with reduced imaging times. However, these results account mainly for body imaging, while no significant difference were found in brain imaging. This overall higher image quality suggests that the acquisition time or injected activity can be reduced by at least 37% on the PET/MR scanner.

PET imaging reveals brain functional changes in internet gaming disorder

Energy Technology Data Exchange (ETDEWEB)

Tian, Mei; Zhang, Ying; Du, Fenglei; Hou, Haifeng; Chao, Fangfang; Zhang, Hong [The Second Hospital of Zhejiang University School of Medicine, Department of Nuclear Medicine, Hangzhou, Zhejiang (China); Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou (China); Chen, Qiaozhen [The Second Hospital of Zhejiang University School of Medicine, Department of Nuclear Medicine, Hangzhou, Zhejiang (China); The Second Affiliated Hospital of Zhejiang University School of Medicine, Department of Psychiatry, Hangzhou (China)

2014-07-15

Internet gaming disorder is an increasing problem worldwide, resulting in critical academic, social, and occupational impairment. However, the neurobiological mechanism of internet gaming disorder remains unknown. The aim of this study is to assess brain dopamine D{sub 2} (D{sub 2})/Serotonin 2A (5-HT{sub 2A}) receptor function and glucose metabolism in the same subjects by positron emission tomography (PET) imaging approach, and investigate whether the correlation exists between D{sub 2} receptor and glucose metabolism. Twelve drug-naive adult males who met criteria for internet gaming disorder and 14 matched controls were studied with PET and {sup 11}C-N-methylspiperone ({sup 11}C-NMSP) to assess the availability of D{sub 2}/5-HT{sub 2A} receptors and with {sup 18}F-fluoro-D-glucose ({sup 18}F-FDG) to assess regional brain glucose metabolism, a marker of brain function. {sup 11}C-NMSP and {sup 18}F-FDG PET imaging data were acquired in the same individuals under both resting and internet gaming task states. In internet gaming disorder subjects, a significant decrease in glucose metabolism was observed in the prefrontal, temporal, and limbic systems. Dysregulation of D{sub 2} receptors was observed in the striatum, and was correlated to years of overuse. A low level of D{sub 2} receptors in the striatum was significantly associated with decreased glucose metabolism in the orbitofrontal cortex. For the first time, we report the evidence that D{sub 2} receptor level is significantly associated with glucose metabolism in the same individuals with internet gaming disorder, which indicates that D{sub 2}/5-HT{sub 2A} receptor-mediated dysregulation of the orbitofrontal cortex could underlie a mechanism for loss of control and compulsive behavior in internet gaming disorder subjects. (orig.)

Imaging Alzheimer's disease pathophysiology with PET

Directory of Open Access Journals (Sweden)

Lucas Porcello Schilling

Full Text Available ABSTRACT Alzheimer's disease (AD has been reconceptualised as a dynamic pathophysiological process characterized by preclinical, mild cognitive impairment (MCI, and dementia stages. Positron emission tomography (PET associated with various molecular imaging agents reveals numerous aspects of dementia pathophysiology, such as brain amyloidosis, tau accumulation, neuroreceptor changes, metabolism abnormalities and neuroinflammation in dementia patients. In the context of a growing shift toward presymptomatic early diagnosis and disease-modifying interventions, PET molecular imaging agents provide an unprecedented means of quantifying the AD pathophysiological process, monitoring disease progression, ascertaining whether therapies engage their respective brain molecular targets, as well as quantifying pharmacological responses. In the present study, we highlight the most important contributions of PET in describing brain molecular abnormalities in AD.

Clinical Evaluation of PET Image Quality as a Function of Acquisition Time in a New TOF-PET/MRI Compared to TOF-PET/CT--Initial Results.

Science.gov (United States)

Zeimpekis, Konstantinos G; Barbosa, Felipe; Hüllner, Martin; ter Voert, Edwin; Davison, Helen; Veit-Haibach, Patrick; Delso, Gaspar

2015-10-01

The purpose of this study was to compare only the performance of the PET component between a TOF-PET/CT (henceforth noted as PET/CT) scanner and an integrated TOF-PET/MRI (henceforth noted as PET/MRI) scanner concerning image quality parameters and quantification in terms of standardized uptake value (SUV) as a function of acquisition time (a surrogate of dose). The CT and MR image quality were not assessed, and that is beyond the scope of this study. Five brain and five whole-body patients were included in the study. The PET/CT scan was used as a reference and the PET/MRI acquisition time was consecutively adjusted, taking into account the decay between the scans in order to expose both systems to the same amount of the emitted signal. The acquisition times were then retrospectively reduced to assess the performance of the PET/MRI for lower count rates. Image quality, image sharpness, artifacts, and noise were evaluated. SUV measurements were taken in the liver and in the white matter to compare quantification. Quantitative evaluation showed strong correlation between PET/CT and PET/MRI brain SUVs. Liver correlation was good, however, with lower uptake estimation in PET/MRI, partially justified by bio-redistribution. The clinical evaluation showed that PET/MRI offers higher image quality and sharpness with lower levels of noise and artifacts compared to PET/CT with reduced acquisition times for whole-body scans while for brain scans there is no significant difference. The TOF-PET/MRI showed higher image quality compared to TOF-PET/CT as tested with reduced imaging times. However, this result accounts mainly for body imaging, while no significant differences were found in brain imaging.

Brain PET scan

Science.gov (United States)

... results on a PET scan. Blood sugar or insulin levels may affect the test results in people with diabetes . PET scans may be done along with a CT scan. This combination scan is called a PET/CT. Alternative Names Brain positron emission tomography; PET scan - brain References Chernecky ...

Deep Learning MR Imaging-based Attenuation Correction for PET/MR Imaging.

Science.gov (United States)

Liu, Fang; Jang, Hyungseok; Kijowski, Richard; Bradshaw, Tyler; McMillan, Alan B

2018-02-01

Purpose To develop and evaluate the feasibility of deep learning approaches for magnetic resonance (MR) imaging-based attenuation correction (AC) (termed deep MRAC) in brain positron emission tomography (PET)/MR imaging. Materials and Methods A PET/MR imaging AC pipeline was built by using a deep learning approach to generate pseudo computed tomographic (CT) scans from MR images. A deep convolutional auto-encoder network was trained to identify air, bone, and soft tissue in volumetric head MR images coregistered to CT data for training. A set of 30 retrospective three-dimensional T1-weighted head images was used to train the model, which was then evaluated in 10 patients by comparing the generated pseudo CT scan to an acquired CT scan. A prospective study was carried out for utilizing simultaneous PET/MR imaging for five subjects by using the proposed approach. Analysis of covariance and paired-sample t tests were used for statistical analysis to compare PET reconstruction error with deep MRAC and two existing MR imaging-based AC approaches with CT-based AC. Results Deep MRAC provides an accurate pseudo CT scan with a mean Dice coefficient of 0.971 ± 0.005 for air, 0.936 ± 0.011 for soft tissue, and 0.803 ± 0.021 for bone. Furthermore, deep MRAC provides good PET results, with average errors of less than 1% in most brain regions. Significantly lower PET reconstruction errors were realized with deep MRAC (-0.7% ± 1.1) compared with Dixon-based soft-tissue and air segmentation (-5.8% ± 3.1) and anatomic CT-based template registration (-4.8% ± 2.2). Conclusion The authors developed an automated approach that allows generation of discrete-valued pseudo CT scans (soft tissue, bone, and air) from a single high-spatial-resolution diagnostic-quality three-dimensional MR image and evaluated it in brain PET/MR imaging. This deep learning approach for MR imaging-based AC provided reduced PET reconstruction error relative to a CT-based standard within the brain compared

In vivo characterization of chronic traumatic encephalopathy using [F-18]FDDNP PET brain imaging.

Science.gov (United States)

Barrio, Jorge R; Small, Gary W; Wong, Koon-Pong; Huang, Sung-Cheng; Liu, Jie; Merrill, David A; Giza, Christopher C; Fitzsimmons, Robert P; Omalu, Bennet; Bailes, Julian; Kepe, Vladimir

2015-04-21

Chronic traumatic encephalopathy (CTE) is an acquired primary tauopathy with a variety of cognitive, behavioral, and motor symptoms linked to cumulative brain damage sustained from single, episodic, or repetitive traumatic brain injury (TBI). No definitive clinical diagnosis for this condition exists. In this work, we used [F-18]FDDNP PET to detect brain patterns of neuropathology distribution in retired professional American football players with suspected CTE (n = 14) and compared results with those of cognitively intact controls (n = 28) and patients with Alzheimer's dementia (AD) (n = 24), a disease that has been cognitively associated with CTE. [F-18]FDDNP PET imaging results in the retired players suggested the presence of neuropathological patterns consistent with models of concussion wherein brainstem white matter tracts undergo early axonal damage and cumulative axonal injuries along subcortical, limbic, and cortical brain circuitries supporting mood, emotions, and behavior. This deposition pattern is distinctively different from the progressive pattern of neuropathology [paired helical filament (PHF)-tau and amyloid-β] in AD, which typically begins in the medial temporal lobe progressing along the cortical default mode network, with no or minimal involvement of subcortical structures. This particular [F-18]FDDNP PET imaging pattern in cases of suspected CTE also is primarily consistent with PHF-tau distribution observed at autopsy in subjects with a history of mild TBI and autopsy-confirmed diagnosis of CTE.

PET imaging in pediatric neuroradiology: current and future applications

Energy Technology Data Exchange (ETDEWEB)

Kim, Sunhee [Children' s Hospital of Pittsburgh of UPMC, Department of Radiology, Pittsburgh, PA (United States); Salamon, Noriko [UCLA David Geffen School of Medicine at UCLA, Department of Radiology, Ronald Reagan UCLA Medical Center, Los Angeles, CA (United States); Jackson, Hollie A.; Blueml, Stefan [Keck School of Medicine of USC, Department of Radiology, Childrens Hospital Los Angeles, Los Angeles, CA (United States); Panigrahy, Ashok [Children' s Hospital of Pittsburgh of UPMC, Department of Radiology, Pittsburgh, PA (United States); Keck School of Medicine of USC, Department of Radiology, Childrens Hospital Los Angeles, Los Angeles, CA (United States)

2010-01-15

Molecular imaging with positron emitting tomography (PET) is widely accepted as an essential part of the diagnosis and evaluation of neoplastic and non-neoplastic disease processes. PET has expanded its role from the research domain into clinical application for oncology, cardiology and neuropsychiatry. More recently, PET is being used as a clinical molecular imaging tool in pediatric neuroimaging. PET is considered an accurate and noninvasive method to study brain activity and to understand pediatric neurological disease processes. In this review, specific examples of the clinical use of PET are given with respect to pediatric neuroimaging. The current use of co-registration of PET with MR imaging is exemplified in regard to pediatric epilepsy. The current use of PET/CT in the evaluation of head and neck lymphoma and pediatric brain tumors is also reviewed. Emerging technologies including PET/MRI and neuroreceptor imaging are discussed. (orig.)

PET imaging in pediatric neuroradiology: current and future applications

International Nuclear Information System (INIS)

Kim, Sunhee; Salamon, Noriko; Jackson, Hollie A.; Blueml, Stefan; Panigrahy, Ashok

2010-01-01

Molecular imaging with positron emitting tomography (PET) is widely accepted as an essential part of the diagnosis and evaluation of neoplastic and non-neoplastic disease processes. PET has expanded its role from the research domain into clinical application for oncology, cardiology and neuropsychiatry. More recently, PET is being used as a clinical molecular imaging tool in pediatric neuroimaging. PET is considered an accurate and noninvasive method to study brain activity and to understand pediatric neurological disease processes. In this review, specific examples of the clinical use of PET are given with respect to pediatric neuroimaging. The current use of co-registration of PET with MR imaging is exemplified in regard to pediatric epilepsy. The current use of PET/CT in the evaluation of head and neck lymphoma and pediatric brain tumors is also reviewed. Emerging technologies including PET/MRI and neuroreceptor imaging are discussed. (orig.)

One-step preparation of [18F]FPBM for PET imaging of serotonin transporter (SERT) in the brain

International Nuclear Information System (INIS)

Qiao, Hongwen; Zhang, Yan; Wu, Zehui; Zhu, Lin; Choi, Seok Rye; Ploessl, Karl; Kung, Hank F.

2016-01-01

Serotonin transporters (SERT) in the brain play an important role in normal brain function. Selective serotonin reuptake inhibitors such as fluoxetine, sertraline, paroxetine, escitalopram, etc., specifically target SERT binding in the brain. Development of SERT imaging agents may be useful for studying the function of SERT by in vivo imaging. A one-step preparation of [ 18 F]FPBM, 2-(2′-(dimethylamino)methyl)-4′-(3-([ 18 F]fluoropropoxy)phenylthio) benzenamine, for positron emission tomography (PET) imaging of SERT binding in the brain was achieved. An active OTs intermediate, 9, was reacted with [ 18 F]F − /K 222 to produce [ 18 F]FPBM in one step and in high radiochemical yield. This labeling reaction was evaluated and optimized under different temperatures, bases, solvents, and varying amounts of precursor 9. The radiolabeling reaction led to the desired [ 18 F]FPBM in one step and the crude product was purified by HPLC purification to give no-carrier-added [ 18 F]FPBM (radiochemical yield, 24–33%, decay corrected; radiochemical purity > 99%). PET imaging studies in normal monkeys (n = 4) showed fast, pronounced uptakes in the midbrain and thalamus, regions known to be rich in SERT binding sites. A displacement experiment with escitalopram (5 mg/kg iv injection at 30 min after [ 18 F]FPBM injection) showed a rapid and complete reversal of SERT binding, suggesting that binding by [ 18 F]FPBM was highly specific and reversible. A one-step radiolabeling method coupled with HPLC purification for preparation of [ 18 F]FPBM was developed. Imaging studies suggest that it is feasible to use this method to prepare [ 18 F]FPBM for in vivo PET imaging of SERT binding in the brain.

Progress of PET imaging in Schizophrenia

International Nuclear Information System (INIS)

Cai Li; Gao Shuo

2011-01-01

PET is an important functional neuroimaging technique that can be used to assessment of cerebral metabolic activity and blood flow and identifies the distribution of important neurotransmitters in the human brain. Compared with other conventional imaging techniques, PET enables regional cerebral glucose metabolism, blood flow, dopaminergic and serotonergic receptor function to be assessed qualitatively and quantitatively. In recent years, PET increasingly being used greatly to advance our understanding of the neurobiology and pathophysiology of schizophrenia. This review focuses on the use of PET tracers in identifying regional brain abnormalities and regions associated with cognitive functioning in schizophrenia. (authors)

Quantitative imaging studies with PET VI. Project II

International Nuclear Information System (INIS)

Copper, M.; Chen, C.T.; Yasillo, N.; Gatley, J.; Ortega, C.; DeJesus, O.; Friedman, A.

1985-01-01

This project is focused upon the development of hardware and software to improve PET image analysis and upon clinical applications of PET. In this report the laboratory's progress in various attenuation correction methods for brain imaging are described. The use of time-of-flight information for image reconstruction is evaluated. The location of dopamine D1 and D2 receptors in brain was found to be largely in the basal ganghia. 1 tab. (DT)

Quantitative imaging of protein targets in the human brain with PET

International Nuclear Information System (INIS)

Gunn, Roger N; Slifstein, Mark; Searle, Graham E; Price, Julie C

2015-01-01

PET imaging of proteins in the human brain with high affinity radiolabelled molecules has a history stretching back over 30 years. During this period the portfolio of protein targets that can be imaged has increased significantly through successes in radioligand discovery and development. This portfolio now spans six major categories of proteins; G-protein coupled receptors, membrane transporters, ligand gated ion channels, enzymes, misfolded proteins and tryptophan-rich sensory proteins. In parallel to these achievements in radiochemical sciences there have also been significant advances in the quantitative analysis and interpretation of the imaging data including the development of methods for image registration, image segmentation, tracer compartmental modeling, reference tissue kinetic analysis and partial volume correction. In this review, we analyze the activity of the field around each of the protein targets in order to give a perspective on the historical focus and the possible future trajectory of the field. The important neurobiology and pharmacology is introduced for each of the six protein classes and we present established radioligands for each that have successfully transitioned to quantitative imaging in humans. We present a standard quantitative analysis workflow for these radioligands which takes the dynamic PET data, associated blood and anatomical MRI data as the inputs to a series of image processing and bio-mathematical modeling steps before outputting the outcome measure of interest on either a regional or parametric image basis. The quantitative outcome measures are then used in a range of different imaging studies including tracer discovery and development studies, cross sectional studies, classification studies, intervention studies and longitudinal studies. Finally we consider some of the confounds, challenges and subtleties that arise in practice when trying to quantify and interpret PET neuroimaging data including motion artifacts

Quantitative imaging of protein targets in the human brain with PET

Science.gov (United States)

Gunn, Roger N.; Slifstein, Mark; Searle, Graham E.; Price, Julie C.

2015-11-01

PET imaging of proteins in the human brain with high affinity radiolabelled molecules has a history stretching back over 30 years. During this period the portfolio of protein targets that can be imaged has increased significantly through successes in radioligand discovery and development. This portfolio now spans six major categories of proteins; G-protein coupled receptors, membrane transporters, ligand gated ion channels, enzymes, misfolded proteins and tryptophan-rich sensory proteins. In parallel to these achievements in radiochemical sciences there have also been significant advances in the quantitative analysis and interpretation of the imaging data including the development of methods for image registration, image segmentation, tracer compartmental modeling, reference tissue kinetic analysis and partial volume correction. In this review, we analyze the activity of the field around each of the protein targets in order to give a perspective on the historical focus and the possible future trajectory of the field. The important neurobiology and pharmacology is introduced for each of the six protein classes and we present established radioligands for each that have successfully transitioned to quantitative imaging in humans. We present a standard quantitative analysis workflow for these radioligands which takes the dynamic PET data, associated blood and anatomical MRI data as the inputs to a series of image processing and bio-mathematical modeling steps before outputting the outcome measure of interest on either a regional or parametric image basis. The quantitative outcome measures are then used in a range of different imaging studies including tracer discovery and development studies, cross sectional studies, classification studies, intervention studies and longitudinal studies. Finally we consider some of the confounds, challenges and subtleties that arise in practice when trying to quantify and interpret PET neuroimaging data including motion artifacts

Human brain imaging

International Nuclear Information System (INIS)

Kuhar, M.J.

1987-01-01

Just as there have been dramatic advances in the molecular biology of the human brain in recent years, there also have been remarkable advances in brain imaging. This paper reports on the development and broad application of microscopic imaging techniques which include the autoradiographic localization of receptors and the measurement of glucose utilization by autoradiography. These approaches provide great sensitivity and excellent anatomical resolution in exploring brain organization and function. The first noninvasive external imaging of receptor distributions in the living human brain was achieved by positron emission tomography (PET) scanning. Developments, techniques and applications continue to progress. Magnetic resonance imaging (MRI) is also becoming important. Its initial clinical applications were in examining the structure and anatomy of the brain. However, more recent uses, such as MRI spectroscopy, indicate the feasibility of exploring biochemical pathways in the brain, the metabolism of drugs in the brain, and also of examining some of these procedures at an anatomical resolution which is substantially greater than that obtainable by PET scanning. The issues will be discussed in greater detail

Is Necessary Attenuation Correction for Cat Brain PET?

International Nuclear Information System (INIS)

Kim, Jin Su; Lee, Jae Sung; Park, Min Hyun; Im, Ki Chun; Oh, Seung Ha; Lee, Dong Soo; Moon, Dae Hyuk

2007-01-01

Photon attenuation and scatter corrections (AC and SC) were necessary for quantification of human PET. However, there is no consensus on whether AC and SC are necessary for the cat brain PET imaging. Since post-injection transmission (TX) PET scans are not permitted or provided to microPET scanner users at present, additional time for performing TX scan and awaiting FDG uptake is required for attenuation and scatter corrections. Increasing probability of subject movement and possible biological effect of long term anesthesia would be the problem in additional TX scan. The aim of this study was to examine the effect of AC and SC for the quantification of cat brain PET data

Net-based data transfer and automatic image fusion of metabolic (PET) and morphologic (CT/MRI) images for radiosurgical planning of brain tumors

International Nuclear Information System (INIS)

Baum, R.P.; Przetak, C.; Schmuecking, M.; Klener, G.; Surber, G.; Hamm, K.

2002-01-01

Aim: The main purpose of radiosurgery in comparison to conventional radiotherapy of brain tumors is to reach a higher radiation dose in the tumor and sparing normal brain tissue as much as possible. To reach this aim it is crucial to define the target volume extremely accurately. For this purpose, MRI and CT examinations are used for radiotherapy planning. In certain cases, however, metabolic information obtained by positron emission tomography (PET) may be useful to achieve a higher therapeutic accuracy by sparing important brain structures. This can be the case, i.e. in low grade astrocytomas for exact delineation of vital tumor as well as in differentiating scaring tissue from tumor recurrence and edema after operation. For this purpose, radiolabeled aminoacid analogues (e.g. C-11 methionine) and recently O-2-[ 18 F] Fluorethyl-L-Tyrosin (F-18 FET) have been introduced as PET tracers to detect the area of highest tumor metabolism which allows to obtain additional information as compared to FDG-PET that reflects the local glucose metabolism. In these cases, anatomical and metabolic data have to be combined with the technique of digital image fusion to exactly determine the target volume, the isodoses and the area where the highest dose has to be applied. Materials: We have set up a data transfer from the PET Center of the Zentralklinik Bad Berka with the Department of Stereotactic Radiation at the Helios Klinik Erfurt (distance approx. 25 km) to enable this kind of image fusion. PET data (ECAT EXACT 47, Siemens/CTI) are transferred to a workstation (NOVALIS) in the Dept. of Stereotactic Radiation to be co-registered with the CT or MRI data of the patient. All PET images are in DICOM format (obtained by using a HERMES computer, Nuclear Diagnostics, Sweden) and can easily be introduced into the NOVALIS workstation. The software uses the optimation of mutual information to achieve a good fusion quality. Sometimes manual corrections have to be performed to get an

MR constrained simultaneous reconstruction of activity and attenuation maps in brain TOF-PET/MR imaging

Energy Technology Data Exchange (ETDEWEB)

Mehranian, Abolfazl; Zaidi, Habib [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211 Geneva (Switzerland)

2014-07-29

The maximum likelihood estimation of attenuation and activity (MLAA) algorithm has been proposed to jointly estimate activity and attenuation from emission data only. Salomon et al employed the MLAA to estimate activity and attenuation from time-of-flight PET data with spatial MR prior information on attenuation. Recently, we proposed a novel algorithm to impose both spatial and statistical constraints on attenuation estimation within the MLAA algorithm using Dixon MR images and a constrained Gaussian mixture model (GMM). In this study, we compare the proposed algorithm with MLAA and MLAA-Salomon in brain TOF-PET/MR imaging.

MR constrained simultaneous reconstruction of activity and attenuation maps in brain TOF-PET/MR imaging

International Nuclear Information System (INIS)

Mehranian, Abolfazl; Zaidi, Habib

2014-01-01

The maximum likelihood estimation of attenuation and activity (MLAA) algorithm has been proposed to jointly estimate activity and attenuation from emission data only. Salomon et al employed the MLAA to estimate activity and attenuation from time-of-flight PET data with spatial MR prior information on attenuation. Recently, we proposed a novel algorithm to impose both spatial and statistical constraints on attenuation estimation within the MLAA algorithm using Dixon MR images and a constrained Gaussian mixture model (GMM). In this study, we compare the proposed algorithm with MLAA and MLAA_Salomon in brain TOF-PET/MR imaging.

Reliability of semiquantitative 18F-FDG PET parameters derived from simultaneous brain PET/MRI: A feasibility study

International Nuclear Information System (INIS)

Jena, Amarnath; Taneja, Sangeeta; Goel, Reema; Renjen, Pushpendranath; Negi, Pradeep

2014-01-01

Purpose: Simultaneous brain PET/MRI faces an important issue of validation of accurate MRI based attenuation correction (AC) method for precise quantitation of brain PET data unlike in PET/CT systems where the use of standard, validated CT based AC is routinely available. The aim of this study was to investigate the feasibility of evaluation of semiquantitative 18 F-FDG PET parameters derived from simultaneous brain PET/MRI using ultrashort echo time (UTE) sequences for AC and to assess their agreement with those obtained from PET/CT examination. Methods: Sixteen patients (age range 18–73 years; mean age 49.43 (19.3) years; 13 men 3 women) underwent simultaneous brain PET/MRI followed immediately by PET/CT. Quantitative analysis of brain PET images obtained from both studies was undertaken using Scenium v.1 brain analysis software package. Twenty ROIs for various brain regions were system generated and 6 semiquantitative parameters including maximum standardized uptake value (SUV max), SUV mean, minimum SUV (SUV min), minimum standard deviation (SD min), maximum SD (SD max) and SD from mean were calculated for both sets of PET data for each patient. Intra-class correlation coefficients (ICCs) were determined to assess agreement between the various semiquantitative parameters for the two PET data sets. Results: Intra-class co-relation between the two PET data sets for SUV max, SUV mean and SD max was highly significant (p < 0.00) for all the 20 predefined brain regions with ICC > 0.9. SD from mean was also found to be statistically significant for all the predefined brain regions with ICC > 0.8. However, SUV max and SUV mean values obtained from PET/MRI were significantly lower compared to those of PET/CT for all the predefined brain regions. Conclusion: PET quantitation accuracy using the MRI based UTE sequences for AC in simultaneous brain PET/MRI is reliable in a clinical setting, being similar to that obtained using PET/CT

Application of a semi-automatic ROI setting system for brain PET images to animal PET studies

International Nuclear Information System (INIS)

Kuge, Yuji; Akai, Nobuo; Tamura, Koji

1998-01-01

ProASSIST, a semi-automatic ROI (region of interest) setting system for human brain PET images, has been modified for use with the canine brain, and the performance of the obtained system was evaluated by comparing the operational simplicity for ROI setting and the consistency of ROI values obtained with those by a conventional manual procedure. Namely, we created segment maps for the canine brain by making reference to the coronal section atlas of the canine brain by Lim et al., and incorporated them into the ProASSIST system. For the performance test, CBF (cerebral blood flow) and CMRglc (cerebral metabolic rate in glucose) images in dogs with or without focal cerebral ischemia were used. In ProASSIST, brain contours were defined semiautomatically. In the ROI analysis of the test image, manual modification of the contour was necessary in half cases examined (8/16). However, the operation was rather simple so that the operation time per one brain section was significantly shorter than that in the manual operation. The ROI values determined by the system were comparable with those by the manual procedure, confirming the applicability of the system to these animal studies. The use of the system like the present one would also merit the more objective data acquisition for the quantitative ROI analysis, because no manual procedure except for some specifications of the anatomical features is required for ROI setting. (author)

Remote transfer of PET images by internet

International Nuclear Information System (INIS)

Zuo Chuantao; Lin Xiangtong; Guan Yihui; Zhao Jun

2003-01-01

The methodology of PET image remote transfer by Internet has been explored. The original images were got with ECAT EXACT HR + PET, and then converted to Dicom format by Mview software. The Dicom images were transferred via Internet. Thus the PET images were transferred via Internet successfully. The ideal images were obtained away from 8 km. The transfer time of brain and whole body image was (37±3)s and (245±10)s respectively, while the transfer rate was (34.7±2.8) kbyte/s and (34.4±1.5)kbyte/s, respectively. The results showed that the remote transfer via Internet was feasible and practical

Multi-atlas attenuation correction supports full quantification of static and dynamic brain PET data in PET-MR

Science.gov (United States)

Mérida, Inés; Reilhac, Anthonin; Redouté, Jérôme; Heckemann, Rolf A.; Costes, Nicolas; Hammers, Alexander

2017-04-01

In simultaneous PET-MR, attenuation maps are not directly available. Essential for absolute radioactivity quantification, they need to be derived from MR or PET data to correct for gamma photon attenuation by the imaged object. We evaluate a multi-atlas attenuation correction method for brain imaging (MaxProb) on static [18F]FDG PET and, for the first time, on dynamic PET, using the serotoninergic tracer [18F]MPPF. A database of 40 MR/CT image pairs (atlases) was used. The MaxProb method synthesises subject-specific pseudo-CTs by registering each atlas to the target subject space. Atlas CT intensities are then fused via label propagation and majority voting. Here, we compared these pseudo-CTs with the real CTs in a leave-one-out design, contrasting the MaxProb approach with a simplified single-atlas method (SingleAtlas). We evaluated the impact of pseudo-CT accuracy on reconstructed PET images, compared to PET data reconstructed with real CT, at the regional and voxel levels for the following: radioactivity images; time-activity curves; and kinetic parameters (non-displaceable binding potential, BPND). On static [18F]FDG, the mean bias for MaxProb ranged between 0 and 1% for 73 out of 84 regions assessed, and exceptionally peaked at 2.5% for only one region. Statistical parametric map analysis of MaxProb-corrected PET data showed significant differences in less than 0.02% of the brain volume, whereas SingleAtlas-corrected data showed significant differences in 20% of the brain volume. On dynamic [18F]MPPF, most regional errors on BPND ranged from -1 to  +3% (maximum bias 5%) for the MaxProb method. With SingleAtlas, errors were larger and had higher variability in most regions. PET quantification bias increased over the duration of the dynamic scan for SingleAtlas, but not for MaxProb. We show that this effect is due to the interaction of the spatial tracer-distribution heterogeneity variation over time with the degree of accuracy of the attenuation maps. This

Predicting standard-dose PET image from low-dose PET and multimodal MR images using mapping-based sparse representation

International Nuclear Information System (INIS)

Wang, Yan; Zhou, Jiliu; Zhang, Pei; An, Le; Ma, Guangkai; Kang, Jiayin; Shi, Feng; Shen, Dinggang; Wu, Xi; Lalush, David S; Lin, Weili

2016-01-01

Positron emission tomography (PET) has been widely used in clinical diagnosis for diseases and disorders. To obtain high-quality PET images requires a standard-dose radionuclide (tracer) injection into the human body, which inevitably increases risk of radiation exposure. One possible solution to this problem is to predict the standard-dose PET image from its low-dose counterpart and its corresponding multimodal magnetic resonance (MR) images. Inspired by the success of patch-based sparse representation (SR) in super-resolution image reconstruction, we propose a mapping-based SR (m-SR) framework for standard-dose PET image prediction. Compared with the conventional patch-based SR, our method uses a mapping strategy to ensure that the sparse coefficients, estimated from the multimodal MR images and low-dose PET image, can be applied directly to the prediction of standard-dose PET image. As the mapping between multimodal MR images (or low-dose PET image) and standard-dose PET images can be particularly complex, one step of mapping is often insufficient. To this end, an incremental refinement framework is therefore proposed. Specifically, the predicted standard-dose PET image is further mapped to the target standard-dose PET image, and then the SR is performed again to predict a new standard-dose PET image. This procedure can be repeated for prediction refinement of the iterations. Also, a patch selection based dictionary construction method is further used to speed up the prediction process. The proposed method is validated on a human brain dataset. The experimental results show that our method can outperform benchmark methods in both qualitative and quantitative measures. (paper)

Motion correction of PET brain images through deconvolution: II. Practical implementation and algorithm optimization

Science.gov (United States)

Raghunath, N.; Faber, T. L.; Suryanarayanan, S.; Votaw, J. R.

2009-02-01

Image quality is significantly degraded even by small amounts of patient motion in very high-resolution PET scanners. When patient motion is known, deconvolution methods can be used to correct the reconstructed image and reduce motion blur. This paper describes the implementation and optimization of an iterative deconvolution method that uses an ordered subset approach to make it practical and clinically viable. We performed ten separate FDG PET scans using the Hoffman brain phantom and simultaneously measured its motion using the Polaris Vicra tracking system (Northern Digital Inc., Ontario, Canada). The feasibility and effectiveness of the technique was studied by performing scans with different motion and deconvolution parameters. Deconvolution resulted in visually better images and significant improvement as quantified by the Universal Quality Index (UQI) and contrast measures. Finally, the technique was applied to human studies to demonstrate marked improvement. Thus, the deconvolution technique presented here appears promising as a valid alternative to existing motion correction methods for PET. It has the potential for deblurring an image from any modality if the causative motion is known and its effect can be represented in a system matrix.

Motion correction of PET brain images through deconvolution: II. Practical implementation and algorithm optimization

International Nuclear Information System (INIS)

Raghunath, N; Faber, T L; Suryanarayanan, S; Votaw, J R

2009-01-01

Image quality is significantly degraded even by small amounts of patient motion in very high-resolution PET scanners. When patient motion is known, deconvolution methods can be used to correct the reconstructed image and reduce motion blur. This paper describes the implementation and optimization of an iterative deconvolution method that uses an ordered subset approach to make it practical and clinically viable. We performed ten separate FDG PET scans using the Hoffman brain phantom and simultaneously measured its motion using the Polaris Vicra tracking system (Northern Digital Inc., Ontario, Canada). The feasibility and effectiveness of the technique was studied by performing scans with different motion and deconvolution parameters. Deconvolution resulted in visually better images and significant improvement as quantified by the Universal Quality Index (UQI) and contrast measures. Finally, the technique was applied to human studies to demonstrate marked improvement. Thus, the deconvolution technique presented here appears promising as a valid alternative to existing motion correction methods for PET. It has the potential for deblurring an image from any modality if the causative motion is known and its effect can be represented in a system matrix.

Motion correction of PET brain images through deconvolution: II. Practical implementation and algorithm optimization

Energy Technology Data Exchange (ETDEWEB)

Raghunath, N; Faber, T L; Suryanarayanan, S; Votaw, J R [Department of Radiology, Emory University Hospital, 1364 Clifton Road, N.E. Atlanta, GA 30322 (United States)], E-mail: John.Votaw@Emory.edu

2009-02-07

Image quality is significantly degraded even by small amounts of patient motion in very high-resolution PET scanners. When patient motion is known, deconvolution methods can be used to correct the reconstructed image and reduce motion blur. This paper describes the implementation and optimization of an iterative deconvolution method that uses an ordered subset approach to make it practical and clinically viable. We performed ten separate FDG PET scans using the Hoffman brain phantom and simultaneously measured its motion using the Polaris Vicra tracking system (Northern Digital Inc., Ontario, Canada). The feasibility and effectiveness of the technique was studied by performing scans with different motion and deconvolution parameters. Deconvolution resulted in visually better images and significant improvement as quantified by the Universal Quality Index (UQI) and contrast measures. Finally, the technique was applied to human studies to demonstrate marked improvement. Thus, the deconvolution technique presented here appears promising as a valid alternative to existing motion correction methods for PET. It has the potential for deblurring an image from any modality if the causative motion is known and its effect can be represented in a system matrix.

PET Imaging Reveals Brain Metabolic Changes in Adolescent Rats Following Chronic Escalating Morphine Administration.

Science.gov (United States)

Chen, Qing; Hou, Haifeng; Feng, Jin; Zhang, Xiaohui; Chen, Yao; Wang, Jing; Ji, Jianfeng; He, Xiao; Wu, Hao; Zhang, Hong

2018-04-10

Non-medical use of prescription opioids, especially among adolescents, has been substantially increased in recent years. However, the neuromechanism remains largely unexplored. In the present study, we aimed to investigate the brain metabolic changes in adolescent rats following chronic escalating morphine administration using positron emission tomography (PET). 2-Deoxy-2-[ 18 F]Fluoro-D-glucose ([ 18 F]FDG) microPET imaging was performed, and statistical parametric mapping (SPM) was used for image analysis. Glucose transporter 3 (Glut-3), dopamine D 2 receptor (D 2 R), and Mμ-opioid receptor (μ-OR) were used for immunostaining analysis. Cerebral glucose metabolism was increased in the corpus callosum (CC) and right retrosplenial dysgranular cortex (rRSD), while it was decreased in the right ventral pallidum (rVP). The expressions of Glut-3, D 2 R, and μ-OR were increased in CC and rRSD, while they were decreased in rVP. Furthermore, glucose metabolism and Glut-3 expression were positively correlated with the expressions of D 2 R or μ-OR in CC, rRSD, and rVP. [ 18 F]FDG microPET brain imaging study in combination with immunohistological investigation revealed that CC, rRSD, and rVP were specifically involved in opioid dependence in adolescents. Our findings provided valuable insights into the neuromechanism of adolescent addiction of prescription opioids and might have important implications for the development of prevention and intervention approaches.

Advantages in functional imaging of the brain.

Science.gov (United States)

Mier, Walter; Mier, Daniela

2015-01-01

As neuronal pathologies cause only minor morphological alterations, molecular imaging techniques are a prerequisite for the study of diseases of the brain. The development of molecular probes that specifically bind biochemical markers and the advances of instrumentation have revolutionized the possibilities to gain insight into the human brain organization and beyond this-visualize structure-function and brain-behavior relationships. The review describes the development and current applications of functional brain imaging techniques with a focus on applications in psychiatry. A historical overview of the development of functional imaging is followed by the portrayal of the principles and applications of positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), two key molecular imaging techniques that have revolutionized the ability to image molecular processes in the brain. We conclude that the juxtaposition of PET and fMRI in hybrid PET/MRI scanners enhances the significance of both modalities for research in neurology and psychiatry and might pave the way for a new area of personalized medicine.

(64)Cu-DOTA-trastuzumab PET imaging and HER2 specificity of brain metastases in HER2-positive breast cancer patients.

Science.gov (United States)

Kurihara, Hiroaki; Hamada, Akinobu; Yoshida, Masayuki; Shimma, Schuichi; Hashimoto, Jun; Yonemori, Kan; Tani, Hitomi; Miyakita, Yasuji; Kanayama, Yousuke; Wada, Yasuhiro; Kodaira, Makoto; Yunokawa, Mayu; Yamamoto, Harukaze; Shimizu, Chikako; Takahashi, Kazuhiro; Watanabe, Yasuyoshi; Fujiwara, Yasuhiro; Tamura, Kenji

2015-01-01

The purpose of this study was to determine whether brain metastases from HER2-positive breast cancer could be detected noninvasively using positron emission tomography (PET) with (64)Cu-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-trastuzumab. PET was performed on five patients with brain metastases from HER2-positive breast cancer, at 24 or 48 h after the injection of approximately 130 MBq of the probe (64)Cu-DOTA-trastuzumab. Radioactivity in metastatic brain tumors was evaluated based on PET images in five patients. Autoradiography, immunohistochemistry (IHC), and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis were performed in one surgical case to confirm HER2 specificity of (64)Cu-DOTA-trastuzumab. Metastatic brain lesions could be visualized by (64)Cu-DOTA-trastuzumab PET in all of five cases, which might indicated that trastuzumab passes through the blood-brain barrier (BBB). The HER2 specificity of (64)Cu-DOTA-trastuzumab was demonstrated in one patient by autoradiography, immunohistochemistry, and LC-MS/MS. Cu-DOTA-trastuzumab PET could be a potential noninvasive procedure for serial identification of metastatic brain lesions in patients with HER2-positive breast cancer. UMIN000004170.

Fusion of PET and MRI for Hybrid Imaging

Science.gov (United States)

Cho, Zang-Hee; Son, Young-Don; Kim, Young-Bo; Yoo, Seung-Schik

Recently, the development of the fusion PET-MRI system has been actively studied to meet the increasing demand for integrated molecular and anatomical imaging. MRI can provide detailed anatomical information on the brain, such as the locations of gray and white matter, blood vessels, axonal tracts with high resolution, while PET can measure molecular and genetic information, such as glucose metabolism, neurotransmitter-neuroreceptor binding and affinity, protein-protein interactions, and gene trafficking among biological tissues. State-of-the-art MRI systems, such as the 7.0 T whole-body MRI, now can visualize super-fine structures including neuronal bundles in the pons, fine blood vessels (such as lenticulostriate arteries) without invasive contrast agents, in vivo hippocampal substructures, and substantia nigra with excellent image contrast. High-resolution PET, known as High-Resolution Research Tomograph (HRRT), is a brain-dedicated system capable of imaging minute changes of chemicals, such as neurotransmitters and -receptors, with high spatial resolution and sensitivity. The synergistic power of the two, i.e., ultra high-resolution anatomical information offered by a 7.0 T MRI system combined with the high-sensitivity molecular information offered by HRRT-PET, will significantly elevate the level of our current understanding of the human brain, one of the most delicate, complex, and mysterious biological organs. This chapter introduces MRI, PET, and PET-MRI fusion system, and its algorithms are discussed in detail.

Head and neck imaging with PET and PET/CT: artefacts from dental metallic implants

International Nuclear Information System (INIS)

Goerres, Gerhard W.; Hany, Thomas F.; Kamel, Ehab; Schulthess von, Gustav K.; Buck, Alfred

2002-01-01

Germanium-68 based attenuation correction (PET Ge68 ) is performed in positron emission tomography (PET) imaging for quantitative measurements. With the recent introduction of combined in-line PET/CT scanners, CT data can be used for attenuation correction. Since dental implants can cause artefacts in CT images, CT-based attenuation correction (PET CT ) may induce artefacts in PET images. The purpose of this study was to evaluate the influence of dental metallic artwork on the quality of PET images by comparing non-corrected images and images attenuation corrected by PET Ge68 and PET CT . Imaging was performed on a novel in-line PET/CT system using a 40-mAs scan for PET CT in 41 consecutive patients with high suspicion of malignant or inflammatory disease. In 17 patients, additional PET Ge68 images were acquired in the same imaging session. Visual analysis of fluorine-18 fluorodeoxyglucose (FDG) distribution in several regions of the head and neck was scored on a 4-point scale in comparison with normal grey matter of the brain in the corresponding PET images. In addition, artefacts adjacent to dental metallic artwork were evaluated. A significant difference in image quality scoring was found only for the lips and the tip of the nose, which appeared darker on non-corrected than on corrected PET images. In 33 patients, artefacts were seen on CT, and in 28 of these patients, artefacts were also seen on PET imaging. In eight patients without implants, artefacts were seen neither on CT nor on PET images. Direct comparison of PET Ge68 and PET CT images showed a different appearance of artefacts in 3 of 17 patients. Malignant lesions were equally well visible using both transmission correction methods. Dental implants, non-removable bridgework etc. can cause artefacts in attenuation-corrected images using either a conventional 68 Ge transmission source or the CT scan obtained with a combined PET/CT camera. We recommend that the non-attenuation-corrected PET images also be

A perspective on the future role of brain pet imaging in exercise science.

Science.gov (United States)

Boecker, Henning; Drzezga, Alexander

2016-05-01

Positron Emission Tomography (PET) bears a unique potential for examining the effects of physical exercise (acute or chronic) within the central nervous system in vivo, including cerebral metabolism, neuroreceptor occupancy, and neurotransmission. However, application of Neuro-PET in human exercise science is as yet surprisingly sparse. To date the field has been dominated by non-invasive neuroelectrical techniques (EEG, MEG) and structural/functional magnetic resonance imaging (sMRI/fMRI). Despite PET having certain inherent disadvantages, in particular radiation exposure and high costs limiting applicability at large scale, certain research questions in human exercise science can exclusively be addressed with PET: The "metabolic trapping" properties of (18)F-FDG PET as the most commonly used PET-tracer allow examining the neuronal mechanisms underlying various forms of acute exercise in a rather unconstrained manner, i.e. under realistic training scenarios outside the scanner environment. Beyond acute effects, (18)F-FDG PET measurements under resting conditions have a strong prospective for unraveling the influence of regular physical activity on neuronal integrity and potentially neuroprotective mechanisms in vivo, which is of special interest for aging and dementia research. Quantification of cerebral glucose metabolism may allow determining the metabolic effects of exercise interventions in the entire human brain and relating the regional cerebral rate of glucose metabolism (rCMRglc) with behavioral, neuropsychological, and physiological measures. Apart from FDG-PET, particularly interesting applications comprise PET ligand studies that focus on dopaminergic and opioidergic neurotransmission, both key transmitter systems for exercise-related psychophysiological effects, including mood changes, reward processing, antinociception, and in its most extreme form 'exercise dependence'. PET ligand displacement approaches even allow quantifying specific endogenous

Simultaneous PET/MR imaging of the brain: feasibility of cerebral blood flow measurements with FAIR-TrueFISP arterial spin labeling MRI.

Science.gov (United States)

Stegger, Lars; Martirosian, Petros; Schwenzer, Nina; Bisdas, Sotirios; Kolb, Armin; Pfannenberg, Christina; Claussen, Claus D; Pichler, Bernd; Schick, Fritz; Boss, Andreas

2012-11-01

Hybrid positron emission tomography/magnetic resonance imaging (PET/MRI) with simultaneous data acquisition promises a comprehensive evaluation of cerebral pathophysiology on a molecular, anatomical, and functional level. Considering the necessary changes to the MR scanner design the feasibility of arterial spin labeling (ASL) is unclear. To evaluate whether cerebral blood flow imaging with ASL is feasible using a prototype PET/MRI device. ASL imaging of the brain with Flow-sensitive Alternating Inversion Recovery (FAIR) spin preparation and true fast imaging in steady precession (TrueFISP) data readout was performed in eight healthy volunteers sequentially on a prototype PET/MRI and a stand-alone MR scanner with 128 × 128 and 192 × 192 matrix sizes. Cerebral blood flow values for gray matter, signal-to-noise and contrast-to-noise ratios, and relative signal change were compared. Additionally, the feasibility of ASL as part of a clinical hybrid PET/MRI protocol was demonstrated in five patients with intracerebral tumors. Blood flow maps showed good delineation of gray and white matter with no discernible artifacts. The mean blood flow values of the eight volunteers on the PET/MR system were 51 ± 9 and 51 ± 7 mL/100 g/min for the 128 × 128 and 192 × 192 matrices (stand-alone MR, 57 ± 2 and 55 ± 5, not significant). The value for signal-to-noise (SNR) was significantly higher for the PET/MRI system using the 192 × 192 matrix size (P change (δS) was significantly lower for the 192 × 192 matrix size (P = 0.02). ASL imaging as part of a clinical hybrid PET/MRI protocol could successfully be accomplished in all patients in diagnostic image quality. ASL brain imaging is feasible with a prototype hybrid PET/MRI scanner, thus adding to the value of this novel imaging technique.

WE-EF-303-06: Feasibility of PET Image-Based On-Line Proton Beam-Range Verification with Simulated Uniform Phantom and Human Brain Studies

International Nuclear Information System (INIS)

Lou, K; Sun, X; Zhu, X; Grosshans, D; Clark, J; Shao, Y

2015-01-01

Purpose: To study the feasibility of clinical on-line proton beam range verification with PET imaging Methods: We simulated a 179.2-MeV proton beam with 5-mm diameter irradiating a PMMA phantom of human brain size, which was then imaged by a brain PET with 300*300*100-mm 3 FOV and different system sensitivities and spatial resolutions. We calculated the mean and standard deviation of positron activity range (AR) from reconstructed PET images, with respect to different data acquisition times (from 5 sec to 300 sec with 5-sec step). We also developed a technique, “Smoothed Maximum Value (SMV)”, to improve AR measurement under a given dose. Furthermore, we simulated a human brain irradiated by a 110-MeV proton beam of 50-mm diameter with 0.3-Gy dose at Bragg peak and imaged by the above PET system with 40% system sensitivity at the center of FOV and 1.7-mm spatial resolution. Results: MC Simulations on the PMMA phantom showed that, regardless of PET system sensitivities and spatial resolutions, the accuracy and precision of AR were proportional to the reciprocal of the square root of image count if image smoothing was not applied. With image smoothing or SMV method, the accuracy and precision could be substantially improved. For a cylindrical PMMA phantom (200 mm diameter and 290 mm long), the accuracy and precision of AR measurement could reach 1.0 and 1.7 mm, with 100-sec data acquired by the brain PET. The study with a human brain showed it was feasible to achieve sub-millimeter accuracy and precision of AR measurement with acquisition time within 60 sec. Conclusion: This study established the relationship between count statistics and the accuracy and precision of activity-range verification. It showed the feasibility of clinical on-line BR verification with high-performance PET systems and improved AR measurement techniques. Cancer Prevention and Research Institute of Texas grant RP120326, NIH grant R21CA187717, The Cancer Center Support (Core) Grant CA016672

PET/MRI for Oncologic Brain Imaging: A Comparison of Standard MR-Based Attenuation Corrections with a Model-Based Approach for the Siemens mMR PET/MR System.

Science.gov (United States)

Rausch, Ivo; Rischka, Lucas; Ladefoged, Claes N; Furtner, Julia; Fenchel, Matthias; Hahn, Andreas; Lanzenberger, Rupert; Mayerhoefer, Marius E; Traub-Weidinger, Tatjana; Beyer, Thomas

2017-09-01

The aim of this study was to compare attenuation-correction (AC) approaches for PET/MRI in clinical neurooncology. Methods: Forty-nine PET/MRI brain scans were included: brain tumor studies using 18 F-fluoro-ethyl-tyrosine ( 18 F-FET) ( n = 31) and 68 Ga-DOTANOC ( n = 7) and studies of healthy subjects using 18 F-FDG ( n = 11). For each subject, MR-based AC maps (MR-AC) were acquired using the standard DIXON- and ultrashort echo time (UTE)-based approaches. A third MR-AC was calculated using a model-based, postprocessing approach to account for bone attenuation values (BD, noncommercial prototype software by Siemens Healthcare). As a reference, AC maps were derived from patient-specific CT images (CTref). PET data were reconstructed using standard settings after AC with all 4 AC methods. We report changes in diagnosis for all brain tumor patients and the following relative differences values (RDs [%]), with regards to AC-CTref: for 18 F-FET (A)-SUVs as well as volumes of interest (VOIs) defined by a 70% threshold of all segmented lesions and lesion-to-background ratios; for 68 Ga-DOTANOC (B)-SUVs as well as VOIs defined by a 50% threshold for all lesions and the pituitary gland; and for 18 F-FDG (C)-RD of SUVs of the whole brain and 10 anatomic regions segmented on MR images. Results: For brain tumor imaging (A and B), the standard PET-based diagnosis was not affected by any of the 3 MR-AC methods. For A, the average RDs of SUV mean were -10%, -4%, and -3% and of the VOIs 1%, 2%, and 7% for DIXON, UTE, and BD, respectively. Lesion-to-background ratios for all MR-AC methods were similar to that of CTref. For B, average RDs of SUV mean were -11%, -11%, and -3% and of the VOIs 1%, -4%, and -3%, respectively. In the case of 18 F-FDG PET/MRI (C), RDs for the whole brain were -11%, -8%, and -5% for DIXON, UTE, and BD, respectively. Conclusion: The diagnostic reading of PET/MR patients with brain tumors did not change with the chosen AC method. Quantitative accuracy of

Radiosynthesis and evaluation of new α1-adrenoceptor antagonists as PET radioligands for brain imaging

International Nuclear Information System (INIS)

Airaksinen, Anu J.; Finnema, Sjoerd J.; Balle, Thomas; Varnäs, Katarina; Bang-Andersen, Benny; Gulyás, Balázs; Farde, Lars; Halldin, Christer

2013-01-01

Introduction: Evaluation of the α 1 -adrenoceptors in relation to brain pathophysiology and drug treatment has been hindered by lack of α 1 -adrenoceptor specific radioligands with sufficient brain exposure. Our aim was to develop an α 1 -adrenoceptor specific PET radioligand for brain imaging. Methods: Two sertindole analogues 1-(4-fluorophenyl)-5-(1-methyl-1H-1,2,4-triazol-3-yl)-3-(1-[ 11 C] methylpiperidin-4-yl)-1H-indole [ 11 C]3 and 1-(4-fluorophenyl)-3-(1-[ 11 C]methylpiperidin-4-yl)-5-(pyrimidin-5-yl) -1H-indole ([ 11 C]Lu AA27122) [ 11 C]4 were synthesized and evaluated as α 1 -adrenoceptor PET radioligands in cynomolgus monkey. Compounds 3 and 4 were selected due to their promising in vitro preclinical profile; high affinity and selectivity for the α 1 -adrenoceptor, favourable blood brain barrier permeability rates in Caco-2 monolayers and promising brain tissue/plasma ratio, assessed by equilibrium dialysis of free fraction in plasma and brain homogenate. Results: Compounds [ 11 C]3 and [ 11 C]4 were synthesized from their desmethyl piperidine precursors with high specific radioactivity (> 370 GBq/μmol) using [ 11 C]methyl iodide. The 1,2,4-triazole analogue [ 11 C]3 exhibited poor brain uptake, but the corresponding pyrimidyl analogue [ 11 C]4 exhibited high brain exposure and binding in α 1 -adrenoceptor rich brain regions. However, the binding could not be inhibited by pretreatment with prazosin (0.1 mg/kg and 0.3 mg/kg). The results were extended by autoradiography of [ 11 C]4 binding in human brain sections and competition with antagonists from different structural families, revealing that only a minor portion of the observed binding of [ 11 C]4 in brain was α 1 -adrenoceptor specific. Conclusion: Though [ 11 C]3 and [ 11 C]4 proved not suitable as PET radioligands, the study provided further understanding of structural features influencing brain exposure of the chemical class of compounds related to the antipsychotic drug sertindole. It

2D VS 3D imaging of brain tumours with 18F-Fluoromisonidazole (FMISO) and positron emission tomography (PET)

International Nuclear Information System (INIS)

Pathmaraj, K.; Scott, A.M.; Egan, G.F.; Hannah, A.; Tauro, A.; Tochon-Danguy, A.; Sachinidis, J.; Berlangieri, S.U.; Fabinyi, G.; McKay, W.J.; Cher, L.

1998-01-01

Full text: 18 F-FMISO accumulates in hypoxic cells and can be used in the PET imaging of brain tumours containing viable but hypoxic cells. The limited activity (typically 130 MBq) of injected 18 F-FMISO yield poor statistics, requiring prolonged imaging in the conventional 2D mode of PET scanning. 3D (septa retracted) imaging allows for more counts to be collected over a shorter time period making it a more practical alternative. This study investigates the contrast resolution that can be obtained from 3D PET scans compared to the corresponding 2D scan. A patient recently diagnosed with brain tumour was injected with 18 -FMISO 2 hours prior to scanning and imaged supine on a 951/31R PET scanner with the head secured firmly in a head holder. The imaging protocol consisted of a 3 min emission rectilinear scan to position the brain in the FOV, a 10 min post-emission transmission scan, a 20 min 2D emission scan and a 5X10 min frames 3D emission scan. Both the 2D and 3D scans were reconstructed with filtered backprojection algorithm. The first 10 min frame of the 3D acquisition was reconstructed. The total true counts were 3 million and 6.06 million in the 2D image and 3D images respectively. The random events were 0.24 million and 0.96 million in the 2D and 3D images respectively. The Noise Equivalent Counts (NEC) were 2.2 million and 2.02 million for the 2D and 3D images respectively indicating that the 2D and 3D scans (in spite of the nominal true events being vastly different in the 2 scans) had similar Signal to Noise Ratio (SNR). Circular ROI's were defined in the tumour and the contralateral cortex in comparable transaxial slices of the 2D and 3D images. Contrast resolution of the tumour to the background was calculated as 1.4 and 1.38 in the 2D and 3D images respectively. Thus comparable contrast resolution is obtained in the brain with both 3D and 2D images, making 3D imaging a viable alternative to 2D imaging and greatly reducing imaging time. Optimum time

Noninvasive Evaluation of Cellular Proliferative Activity in Brain Neurogenic Regions in Rats under Depression and Treatment by Enhanced [18F]FLT-PET Imaging.

Science.gov (United States)

Tamura, Yasuhisa; Takahashi, Kayo; Takata, Kumi; Eguchi, Asami; Yamato, Masanori; Kume, Satoshi; Nakano, Masayuki; Watanabe, Yasuyoshi; Kataoka, Yosky

2016-08-03

Neural stem cells in two neurogenic regions, the subventricular zone and the subgranular zone (SGZ) of the hippocampal dentate gyrus, can divide and produce new neurons throughout life. Hippocampal neurogenesis is related to emotions, including depression/anxiety, and the therapeutic effects of antidepressants, as well as learning and memory. The establishment of in vivo imaging for proliferative activity of neural stem cells in the SGZ might be used to diagnose depression and to monitor the therapeutic efficacy of antidepressants. Positron emission tomography (PET) imaging with 3'-deoxy-3'-[(18)F]fluoro-l-thymidine ([(18)F]FLT) has been studied to allow visualization of proliferative activity in two neurogenic regions of adult mammals; however, the PET imaging has not been widely used because of lower accumulation of [(18)F]FLT, which does not allow quantitative assessment of the decline in cellular proliferative activity in the SGZ under the condition of depression. We report the establishment of an enhanced PET imaging method with [(18)F]FLT combined with probenecid, an inhibitor of drug transporters at the blood-brain barrier, which can allow the quantitative visualization of neurogenic activity in rats. Enhanced PET imaging allowed us to evaluate reduced cell proliferation in the SGZ of rats with corticosterone-induced depression, and further the recovery of proliferative activity in rats under treatment with antidepressants. This enhanced [(18)F]FLT-PET imaging technique with probenecid can be used to assess the dynamic alteration of neurogenic activity in the adult mammalian brain and may also provide a means for objective diagnosis of depression and monitoring of the therapeutic effect of antidepressant treatment. Adult hippocampal neurogenesis may play a role in major depression and antidepressant therapy. Establishment of in vivo imaging for hippocampal neurogenic activity may be useful to diagnose depression and monitor the therapeutic efficacy of

Progress in PET imaging evaluating of traumatic brain injury%创伤性脑损伤PET显像研究进展

Institute of Scientific and Technical Information of China (English)

于明明; 王振光

2015-01-01

Traumatic brain injury (TBI) is the damage of brain tissue caused by external injuries and it has a higher incidence of incidence rate and death rate.It is difficult to diagnose TBI with classic medical imaging technology.PET is an imaging technology that can measure the cerebral glycometabolism and cerebral blood flow quantitatively.It can display the brain functional change caused by TBI.Currently,18F-FDG PET imaging can diagnose TBI by evaluating the cerebral glycometabolism and cerebral blood flow variation.This paper has comprehensively discussed the current conditions of 18F-FDG PET imaging and cerebral blood flow perfusion PET imaging.%创伤性脑损伤(TBI)是由外伤引起的脑组织损害,有着较高的发生率及病死率.传统医学影像学技术难以做出诊断.PET作为一种定量测定脑糖代谢及脑血流量变化的显像技术,可以比较精确地显示TBI所致的脑功能变化.目前,18F-FDG PET显像通过评价脑内葡萄糖代谢及脑血流量变化对TBI做出诊断.笔者对TBI18F-FDG PET显像及脑血流灌注显像进行综述.

Simultaneous fMRI-PET of the opioidergic pain system in human brain

DEFF Research Database (Denmark)

Wey, Hsiao-Ying; Catana, Ciprian; Hooker, Jacob M

2014-01-01

distinct components of the blood oxygenation level dependent (BOLD) fMRI signal has not yet been shown. We obtained sixteen fMRI-PET data sets from eight healthy volunteers. Each subject participated in randomized order in a pain scan and a control (nonpainful pressure) scan on the same day. Dynamic PET......MRI and PET provide complementary information for studying brain function. While the potential use of simultaneous MRI/PET for clinical diagnostic and disease staging has been demonstrated recently; the biological relevance of concurrent functional MRI-PET brain imaging to dissect neurochemically...... data were acquired with an opioid radioligand, [(11)C]diprenorphine, to detect endogenous opioid releases in response to pain. BOLD fMRI data were collected at the same time to capture hemodynamic responses. In this simultaneous human fMRI-PET imaging study, we show co-localized responses in thalamus...

Oncological applications of 18F-FDG PET imaging

International Nuclear Information System (INIS)

Li Lin

2000-01-01

Considering normal distribution of 18 F-FDG in human body, 18 F-FDG imaging using PET can be applied to brain tumors, colorectal cancer, lymphoma, melanoma, lung cancer and head and neck cancer. The author briefly focuses on application of 18 F-FDG PET imaging to breast cancer, pancreatic cancer, hepatocellular carcinoma, musculoskeletal neoplasms, endocrine neoplasms, genitourinary neoplasms, esophageal and gastric carcinomas

Quantification of 18F-FDG PET images using probabilistic brain atlas: clinical application in temporal lobe epilepsy patients

International Nuclear Information System (INIS)

Kang, Keon Wook; Lee, Dong Soo; Cho, Jae Hoon; Lee, Jae Sung; Yeo, Jeong Seok; Lee, Sang Gun; Chung, June Key; Lee, Myung Chul

2000-01-01

A probabilistic atlas of the human brain (Statistical Probability Anatomical Maps: SPAM) was developed by the international consortium for brain mapping (ICBM). After calculating the counts in volume of interest (VOI) using the product of probability of SPAM images and counts in FDG images, asymmetric indexes(AI) were calculated and used for finding epileptogenic zones in temporal lobe epilepsy (TLE). FDG PET images from 28 surgically confirmed TLE patients and 12 age-matched controls were spatially normalized to the averaged brain MRI atlas of ICBM. The counts from normalized PET images were multiplied with the probability of 12 VOIs (superior temporal gyrus, middle temporal gyrus, inferior temporal gyrus, hippocampus, parahippocampal gyrus, and amygdala in each hemisphere) of SPAM images of Montreal Neurological Institute. Finally AI was calculated on each pair of VOI, and compared with visual assessment. If AI was deviated more than 2 standard deviation of normal controls, we considered epileptogenic zones were found successfully. The counts of VOIs in normal controls were symmetric (AI 0.05) except those of inferior temporal gyrus (p<0.01). AIs in 5 pairs of VOI excluding inferior temporal gyrus were deviated to one side in TLE (p<0.05). Lateralization was correct in 23/28 of patients by AI, but all of 28 were consistent with visual inspection. In 3 patients with normal AI was symmetric on visual inspection. In 2 patients falsely lateralized using AI, metabolism was also decreased visually on contra-lateral side. Asymmetric index obtained by the product of statistical probability anatomical map and FDG PET correlated well with visual assessment in TLE patients. SPAM is useful for quantification of VOIs in functional images

Evaluation of a video-based head motion tracking system for dedicated brain PET

Science.gov (United States)

Anishchenko, S.; Beylin, D.; Stepanov, P.; Stepanov, A.; Weinberg, I. N.; Schaeffer, S.; Zavarzin, V.; Shaposhnikov, D.; Smith, M. F.

2015-03-01

Unintentional head motion during Positron Emission Tomography (PET) data acquisition can degrade PET image quality and lead to artifacts. Poor patient compliance, head tremor, and coughing are examples of movement sources. Head motion due to patient non-compliance can be an issue with the rise of amyloid brain PET in dementia patients. To preserve PET image resolution and quantitative accuracy, head motion can be tracked and corrected in the image reconstruction algorithm. While fiducial markers can be used, a contactless approach is preferable. A video-based head motion tracking system for a dedicated portable brain PET scanner was developed. Four wide-angle cameras organized in two stereo pairs are used for capturing video of the patient's head during the PET data acquisition. Facial points are automatically tracked and used to determine the six degree of freedom head pose as a function of time. The presented work evaluated the newly designed tracking system using a head phantom and a moving American College of Radiology (ACR) phantom. The mean video-tracking error was 0.99±0.90 mm relative to the magnetic tracking device used as ground truth. Qualitative evaluation with the ACR phantom shows the advantage of the motion tracking application. The developed system is able to perform tracking with accuracy close to millimeter and can help to preserve resolution of brain PET images in presence of movements.

MR-based automatic delineation of volumes of interest in human brain PET images using probability maps

DEFF Research Database (Denmark)

Svarer, Claus; Madsen, Karina; Hasselbalch, Steen G.

2005-01-01

subjects' MR-images, where VOI sets have been defined manually. High-resolution structural MR-images and 5-HT(2A) receptor binding PET-images (in terms of (18)F-altanserin binding) from 10 healthy volunteers and 10 patients with mild cognitive impairment were included for the analysis. A template including...... 35 VOIs was manually delineated on the subjects' MR images. Through a warping algorithm template VOI sets defined from each individual were transferred to the other subjects MR-images and the voxel overlap was compared to the VOI set specifically drawn for that particular individual. Comparisons were...... delineation of the VOI set. The approach was also shown to work equally well in individuals with pronounced cerebral atrophy. Probability-map-based automatic delineation of VOIs is a fast, objective, reproducible, and safe way to assess regional brain values from PET or SPECT scans. In addition, the method...

Anatomically guided voxel-based partial volume effect correction in brain PET : Impact of MRI segmentation

NARCIS (Netherlands)

Gutierrez, Daniel; Montandon, Marie-Louise; Assal, Frederic; Allaoua, Mohamed; Ratib, Osman; Loevblad, Karl-Olof; Zaidi, Habib

2012-01-01

Partial volume effect is still considered one of the main limitations in brain PET imaging given the limited spatial resolution of current generation PET scanners. The accuracy of anatomically guided partial volume effect correction (PVC) algorithms in brain PET is largely dependent on the

Ultra fast, accurate PET image reconstruction for the Siemens hybrid MR/BrainPET scanner using raw LOR data

International Nuclear Information System (INIS)

Scheins, Juergen; Lerche, Christoph; Shah, Jon

2015-01-01

Fast PET image reconstruction algorithms usually use a Line-of-Response (LOR) preprocessing step where the detected raw LOR data are interpolated either to evenly spaced sinogram projection bins or alternatively to a generic projection space as for example proposed by the PET Reconstruction Software Toolkit (PRESTO) [1]. In this way, speed-optimised, versatile geometrical projectors can be implemented for iterative image reconstruction independent of the underlying scanner geometry. However, all strategies of projection data interpolation unavoidably lead to a loss of original information and result in some degradation of image quality. Here, direct LOR reconstructions overcome this evident drawback at cost of a massively enhanced computational burden. Therefore, computational optimisation techniques are essential to make such demanding approaches attractive and economical for widespread usage in the clinical environment. In this paper, we demonstrate for the Siemens Hybrid MR/BrainPET with 240 million physical LORs that a very fast quantitative direct LOR reconstruction can be realized using a modified version of PRESTO. Now, PRESTO is also capable to directly use sets of symmetric physical LORs instead of interpolating LORs to a generic projection space. Exploiting basic scanner symmetries together with the technique of Single Instruction Multipe Data (SIMD) and Simultaneous Multi-Threading (SMT) results in an overall calculation time of 2-3 minutes per frame on a single multi-core machine, i.e. neither requiring a cluster of mutliple machines nor Graphics Processing Units (GPUs).

Ultra fast, accurate PET image reconstruction for the Siemens hybrid MR/BrainPET scanner using raw LOR data

Energy Technology Data Exchange (ETDEWEB)

Scheins, Juergen; Lerche, Christoph; Shah, Jon [Forschungszentrum Jülich GmbH, Jülich (Germany)

2015-05-18

Fast PET image reconstruction algorithms usually use a Line-of-Response (LOR) preprocessing step where the detected raw LOR data are interpolated either to evenly spaced sinogram projection bins or alternatively to a generic projection space as for example proposed by the PET Reconstruction Software Toolkit (PRESTO) [1]. In this way, speed-optimised, versatile geometrical projectors can be implemented for iterative image reconstruction independent of the underlying scanner geometry. However, all strategies of projection data interpolation unavoidably lead to a loss of original information and result in some degradation of image quality. Here, direct LOR reconstructions overcome this evident drawback at cost of a massively enhanced computational burden. Therefore, computational optimisation techniques are essential to make such demanding approaches attractive and economical for widespread usage in the clinical environment. In this paper, we demonstrate for the Siemens Hybrid MR/BrainPET with 240 million physical LORs that a very fast quantitative direct LOR reconstruction can be realized using a modified version of PRESTO. Now, PRESTO is also capable to directly use sets of symmetric physical LORs instead of interpolating LORs to a generic projection space. Exploiting basic scanner symmetries together with the technique of Single Instruction Multipe Data (SIMD) and Simultaneous Multi-Threading (SMT) results in an overall calculation time of 2-3 minutes per frame on a single multi-core machine, i.e. neither requiring a cluster of mutliple machines nor Graphics Processing Units (GPUs).

Non-invasive grading of brain tumours using dynamic amino acid PET imaging: does it work for 11C-Methionine?

International Nuclear Information System (INIS)

Moulin-Romsee, Gerard; D'Hondt, Eduard; Mortelmans, Luc; Laere, Koen van; Groot, Tjibbe de; Goffin, Jan; Sciot, Raf; Menten, Johan; Bormans, Guy

2007-01-01

Static imaging of amino acids does not allow differentiation of low versus high grade brain tumours. It has been shown that dynamic imaging of the amino acid analogue 18 F-fluoroethyltyrosine (FET) can achieve this goal. In many centres, 11 C-methionine (MET) is used for tumour imaging, but no clinical studies on the use of dynamic scanning for grading have been performed. Thirty-four patients with primary brain glioma and histopathological confirmation were retrospectively studied using 40 min dynamic MET-PET with 220 MBq 11C-methionine. In relation to histopathological grading, various metabolic indices and temporal parameters as documented by Poepperl et al. (JNM 2006;47:393-403) were analyzed. None of the evaluated static or temporal parameters allowed discrimination between high and low grade tumours. On average, low grade tumours showed washout after the initial uptake maximum, while both increases and decreases were seen for high grade tumours. Only the relative early versus late uptake ratio showed a trend towards significance (-0.16 ± 0.17 for low grade versus 0.01 ± 0.25 for high grade; p = 0.07). Unlike FET-PET, the uptake characteristics of MET-PET do not allow classification of low and high grade tumours on an individual patient basis. Since literature data indicate that both tracers have a similar performance regarding biopsy location, tumour delineation, and detection of recurrence, FET-PET should be advocated over MET-PET as its uptake mechanism also allows noninvasive grading in glioma. (orig.)

Automatic delineation of brain regions on MRI and PET images from the pig

DEFF Research Database (Denmark)

Villadsen, Jonas; Hansen, Hanne D; Jørgensen, Louise M

2018-01-01

: Manual inter-modality spatial normalization to a MRI atlas is operator-dependent, time-consuming, and can be inaccurate with lack of cortical radiotracer binding or skull uptake. NEW METHOD: A parcellated PET template that allows for automatic spatial normalization to PET images of any radiotracer....... RESULTS: MRI and [11C]Cimbi-36 PET scans obtained in sixteen pigs made the basis for the atlas. The high resolution MRI scans allowed for creation of an accurately averaged MRI template. By aligning the within-subject PET scans to their MRI counterparts, an averaged PET template was created in the same...... the MRI template with individual MRI images and 0.92±0.26mm using the PET template with individual [11C]Cimbi-36 PET images. We tested the automatic procedure by assessing eleven PET radiotracers with different kinetics and spatial distributions by using perfusion-weighted images of early PET time frames...

Lesions inflammatory activity quantification in multiple sclerosis using ["1"1C]-(R)-PK11195 PET brain images

International Nuclear Information System (INIS)

Schuck, Phelipi N.; Narciso, Lucas D.L.; Dartora, Caroline M.; Silva, Ana M. Marques da

2016-01-01

The criteria for multiple sclerosis (MS) diagnosis include the presence of lesions in brain regions called black holes (BH), characterized by low signal on magnetic resonance imaging T1-weighted. Studies suggest that lesions in MS, if there is an inflammatory process, can be detected in PET imaging with ["1"1C]- (R)-PK11195. The aim of this study is to investigate the uptake of ["1"1C]-(R)-PK11195 in BH in PET images, searching for inflammation activity in lesions and neighborhoods. Semiquantitative methods of SUV and uptake normalization were applied to PET images, in different time intervals, acquired from 8 MS patients and 5 healthy controls. Higher uptake was identified in BH and its edges, when compared with health controls white matter, when the SUV method is applied (p < 0,01, 40 to 60 min). When uptake normalization method is applied, smaller uptake in black holes and its your edges is observed, when compared with white matter apparently healthy (p < 0,01, 0 to 60 min). (author)

Bayesian PET image reconstruction incorporating anato-functional joint entropy

International Nuclear Information System (INIS)

Tang Jing; Rahmim, Arman

2009-01-01

We developed a maximum a posterior (MAP) reconstruction method for positron emission tomography (PET) image reconstruction incorporating magnetic resonance (MR) image information, with the joint entropy between the PET and MR image features serving as the regularization constraint. A non-parametric method was used to estimate the joint probability density of the PET and MR images. Using realistically simulated PET and MR human brain phantoms, the quantitative performance of the proposed algorithm was investigated. Incorporation of the anatomic information via this technique, after parameter optimization, was seen to dramatically improve the noise versus bias tradeoff in every region of interest, compared to the result from using conventional MAP reconstruction. In particular, hot lesions in the FDG PET image, which had no anatomical correspondence in the MR image, also had improved contrast versus noise tradeoff. Corrections were made to figures 3, 4 and 6, and to the second paragraph of section 3.1 on 13 November 2009. The corrected electronic version is identical to the print version.

Prediction of CT Substitutes from MR Images Based on Local Diffeomorphic Mapping for Brain PET Attenuation Correction.

Science.gov (United States)

Wu, Yao; Yang, Wei; Lu, Lijun; Lu, Zhentai; Zhong, Liming; Huang, Meiyan; Feng, Yanqiu; Feng, Qianjin; Chen, Wufan

2016-10-01

Attenuation correction is important for PET reconstruction. In PET/MR, MR intensities are not directly related to attenuation coefficients that are needed in PET imaging. The attenuation coefficient map can be derived from CT images. Therefore, prediction of CT substitutes from MR images is desired for attenuation correction in PET/MR. This study presents a patch-based method for CT prediction from MR images, generating attenuation maps for PET reconstruction. Because no global relation exists between MR and CT intensities, we propose local diffeomorphic mapping (LDM) for CT prediction. In LDM, we assume that MR and CT patches are located on 2 nonlinear manifolds, and the mapping from the MR manifold to the CT manifold approximates a diffeomorphism under a local constraint. Locality is important in LDM and is constrained by the following techniques. The first is local dictionary construction, wherein, for each patch in the testing MR image, a local search window is used to extract patches from training MR/CT pairs to construct MR and CT dictionaries. The k-nearest neighbors and an outlier detection strategy are then used to constrain the locality in MR and CT dictionaries. Second is local linear representation, wherein, local anchor embedding is used to solve MR dictionary coefficients when representing the MR testing sample. Under these local constraints, dictionary coefficients are linearly transferred from the MR manifold to the CT manifold and used to combine CT training samples to generate CT predictions. Our dataset contains 13 healthy subjects, each with T1- and T2-weighted MR and CT brain images. This method provides CT predictions with a mean absolute error of 110.1 Hounsfield units, Pearson linear correlation of 0.82, peak signal-to-noise ratio of 24.81 dB, and Dice in bone regions of 0.84 as compared with real CTs. CT substitute-based PET reconstruction has a regression slope of 1.0084 and R 2 of 0.9903 compared with real CT-based PET. In this method, no

Resting functional imaging tools (MRS, SPECT, PET and PCT).

Science.gov (United States)

Van Der Naalt, J

2015-01-01

Functional imaging includes imaging techniques that provide information about the metabolic and hemodynamic status of the brain. Most commonly applied functional imaging techniques in patients with traumatic brain injury (TBI) include magnetic resonance spectroscopy (MRS), single photon emission computed tomography (SPECT), positron emission tomography (PET) and perfusion CT (PCT). These imaging modalities are used to determine the extent of injury, to provide information for the prediction of outcome, and to assess evidence of cerebral ischemia. In TBI, secondary brain damage mainly comprises ischemia and is present in more than 80% of fatal cases with traumatic brain injury (Graham et al., 1989; Bouma et al., 1991; Coles et al., 2004). In particular, while SPECT measures cerebral perfusion and MRS determines metabolism, PET is able to assess both perfusion and cerebral metabolism. This chapter will describe the application of these techniques in traumatic brain injury separately for the major groups of severity comprising the mild and moderate to severe group. The application in TBI and potential difficulties of each technique is described. The use of imaging techniques in children will be separately outlined. © 2015 Elsevier B.V. All rights reserved.

MicroPET imaging of 5-HT{sub 1A} receptors in rat brain: a test-retest [{sup 18}F]MPPF study

Energy Technology Data Exchange (ETDEWEB)

Aznavour, Nicolas [McGill University, Department of Psychiatry, Montreal, QC (Canada)]|[Laboratory of Neuroenergetics and Cellular Dynamics, EPFL, SV, BMI, Lausanne (Switzerland); Benkelfat, Chawki; Gravel, Paul [McGill University, Department of Psychiatry, Montreal, QC (Canada)]|[McGill University, Department of Neurology and Neurosurgery, Montreal, QC (Canada); Aliaga, Antonio [McGill University, Department of Small Animal Imaging Laboratory, Montreal, QC (Canada); Rosa-Neto, Pedro [Douglas Hospital, Molecular NeuroImaging Laboratory, Montreal, QC (Canada); Bedell, Barry [McGill University, Department of Neurology and Neurosurgery, Montreal, QC (Canada)]|[McGill University, Department of Small Animal Imaging Laboratory, Montreal, QC (Canada); Zimmer, Luc [CERMEP, ANIMAGE Department, Lyon (France)]|[Universite Lyon 1 and CNRS, Lyon (France); Descarries, Laurent [Universite de Montreal, Department of Pathology and Cell Biology, Montreal, QC (Canada)]|[Universite de Montreal, Department of Physiology, Montreal, QC (Canada)]|[Universite de Montreal, GRSNC, Montreal, QC (Canada)

2009-01-15

Earlier studies have shown that positron emission tomography (PET) imaging with the radioligand [{sup 18}F]MPPF allows for measuring the binding potential of serotonin 5-hydroxytryptamine{sub 1A} (5-HT{sub 1A}) receptors in different regions of animal and human brain, including that of 5-HT{sub 1A} autoreceptors in the raphe nuclei. In the present study, we sought to determine if such data could be obtained in rat, with a microPET (R4, Concorde Microsystems). Scans from isoflurane-anaesthetised rats (n = 18, including six test-retest) were co-registered with magnetic resonance imaging data, and binding potential, blood to plasma ratio and radiotracer efflux were estimated according to a simplified reference tissue model. Values of binding potential for hippocampus (1.2), entorhinal cortex (1.1), septum (1.1), medial prefrontal cortex (1.0), amygdala (0.8), raphe nuclei (0.6), paraventricular hypothalamic nucleus (0.5) and raphe obscurus (0.5) were comparable to those previously measured with PET in cats, non-human primates or humans. Test-retest variability was in the order of 10% in the larger brain regions (hippocampus, medial prefrontal and entorhinal cortex) and less than 20% in small nuclei such as the septum and the paraventricular hypothalamic, basolateral amygdaloid and raphe nuclei. MicroPET brain imaging of 5-HT{sub 1A} receptors with [{sup 18}F]MPPF thus represents a promising avenue for investigating 5-HT{sub 1A} receptor function in rat. (orig.)

Brain connectivity study of brain tumor patients using MR-PET data: preliminary results

International Nuclear Information System (INIS)

Mendes, Ana Carina; Ribeiro, Andre Santos; Oros-Peusquens, Ana Maria; Langen, Karl Josef; Shah, Jon; Ferreira, Hugo Alexandre

2015-01-01

Brain activity results from anatomical and functional connections that can be disrupted or altered due to trauma or lesion. This work presents a first approach on the study of whole-brain connectivity of brain tumor patients using the Multimodal Imaging Brain Connectivity (MIBCA) toolbox. Two patients with glioblastoma lesions located in the left hemisphere (one in the motor cortex and the other in the temporal lobe) underwent simultaneous MRI and dynamic PET scans using a 3T MRI scanner with a BrainPET insert. The following data was acquired: T1-w MPRAGE (1x1x1mm 3 ), DTI (dir=30, b=0,800s/mm2, 2x2x2mm 3 ), and dynamic 18F-FET PET. The MIBCA toolbox was used to automatically pre-process MRI-PET data and to derive imaging and connectivity metrics from the multimodal data. Computed metrics included: cortical thickness from T1-w data; mean diffusivity (MD), fractional anisotropy (FA), node degree, clustering coefficient and pairwise ROI fibre tracking (structural connectivity) from DTI data; and standardized uptake value (SUV) from PET data. For all the metrics, the differences between left and right hemispherical structures were obtained, followed by a 25% threshold (except for SUV thresholded at 15%). Data was visualized in a connectogram, and both structural connectivity and metrics were studied in regions surrounding lesions. Preliminary results showed increased SUV values in regions surrounding the tumor for both patients. Patients also showed changes in structural connectivity involving these regions and also other more spatially distant regions such as the putamen and the pallidum, including decreased number of fibers between the subcortical structures themselves and with frontal regions. These findings suggest that the presence of a tumor may alter both local and more distant structural connections. Presently, a larger patient sample is being studied along with the inclusion of a control group to test the consistency of the findings.

Brain connectivity study of brain tumor patients using MR-PET data: preliminary results

Energy Technology Data Exchange (ETDEWEB)

Mendes, Ana Carina [Institute of Biophysics and Biomedical Engineering, Faculty of Sciences of the University of Lisbon (Portugal); Ribeiro, Andre Santos [Institute of Biophysics and Biomedical Engineering, Faculty of Sciences of the University of Lisbon (Portugal); Centre for Neuropsychopharmacology, Division of Brain Sciences, Department of Medicine, Imperial College London, London (United Kingdom); Oros-Peusquens, Ana Maria; Langen, Karl Josef; Shah, Jon [Institute of Neuroscience and Medicine - 4, Forschungszentrum Juelich (Germany); Ferreira, Hugo Alexandre [Institute of Biophysics and Biomedical Engineering, Faculty of Sciences of the University of Lisbon (Portugal)

2015-05-18

Brain activity results from anatomical and functional connections that can be disrupted or altered due to trauma or lesion. This work presents a first approach on the study of whole-brain connectivity of brain tumor patients using the Multimodal Imaging Brain Connectivity (MIBCA) toolbox. Two patients with glioblastoma lesions located in the left hemisphere (one in the motor cortex and the other in the temporal lobe) underwent simultaneous MRI and dynamic PET scans using a 3T MRI scanner with a BrainPET insert. The following data was acquired: T1-w MPRAGE (1x1x1mm{sup 3}), DTI (dir=30, b=0,800s/mm2, 2x2x2mm{sup 3}), and dynamic 18F-FET PET. The MIBCA toolbox was used to automatically pre-process MRI-PET data and to derive imaging and connectivity metrics from the multimodal data. Computed metrics included: cortical thickness from T1-w data; mean diffusivity (MD), fractional anisotropy (FA), node degree, clustering coefficient and pairwise ROI fibre tracking (structural connectivity) from DTI data; and standardized uptake value (SUV) from PET data. For all the metrics, the differences between left and right hemispherical structures were obtained, followed by a 25% threshold (except for SUV thresholded at 15%). Data was visualized in a connectogram, and both structural connectivity and metrics were studied in regions surrounding lesions. Preliminary results showed increased SUV values in regions surrounding the tumor for both patients. Patients also showed changes in structural connectivity involving these regions and also other more spatially distant regions such as the putamen and the pallidum, including decreased number of fibers between the subcortical structures themselves and with frontal regions. These findings suggest that the presence of a tumor may alter both local and more distant structural connections. Presently, a larger patient sample is being studied along with the inclusion of a control group to test the consistency of the findings.

Towards Implementing an MR-based PET Attenuation Correction Method for Neurological Studies on the MR-PET Brain Prototype

Science.gov (United States)

Catana, Ciprian; van der Kouwe, Andre; Benner, Thomas; Michel, Christian J.; Hamm, Michael; Fenchel, Matthias; Fischl, Bruce; Rosen, Bruce; Schmand, Matthias; Sorensen, A. Gregory

2013-01-01

A number of factors have to be considered for implementing an accurate attenuation correction (AC) in a combined MR-PET scanner. In this work, some of these challenges were investigated and an AC method based entirely on the MR data obtained with a single dedicated sequence was developed and used for neurological studies performed with the MR-PET human brain scanner prototype. Methods The focus was on the bone/air segmentation problem, the bone linear attenuation coefficient selection and the RF coil positioning. The impact of these factors on the PET data quantification was studied in simulations and experimental measurements performed on the combined MR-PET scanner. A novel dual-echo ultra-short echo time (DUTE) MR sequence was proposed for head imaging. Simultaneous MR-PET data were acquired and the PET images reconstructed using the proposed MR-DUTE-based AC method were compared with the PET images reconstructed using a CT-based AC. Results Our data suggest that incorrectly accounting for the bone tissue attenuation can lead to large underestimations (>20%) of the radiotracer concentration in the cortex. Assigning a linear attenuation coefficient of 0.143 or 0.151 cm−1 to bone tissue appears to give the best trade-off between bias and variability in the resulting images. Not identifying the internal air cavities introduces large overestimations (>20%) in adjacent structures. Based on these results, the segmented CT AC method was established as the “silver standard” for the segmented MR-based AC method. Particular to an integrated MR-PET scanner, ignoring the RF coil attenuation can cause large underestimations (i.e. up to 50%) in the reconstructed images. Furthermore, the coil location in the PET field of view has to be accurately known. Good quality bone/air segmentation can be performed using the DUTE data. The PET images obtained using the MR-DUTE- and CT-based AC methods compare favorably in most of the brain structures. Conclusion An MR-DUTE-based AC

Toward implementing an MRI-based PET attenuation-correction method for neurologic studies on the MR-PET brain prototype.

Science.gov (United States)

Catana, Ciprian; van der Kouwe, Andre; Benner, Thomas; Michel, Christian J; Hamm, Michael; Fenchel, Matthias; Fischl, Bruce; Rosen, Bruce; Schmand, Matthias; Sorensen, A Gregory

2010-09-01

Several factors have to be considered for implementing an accurate attenuation-correction (AC) method in a combined MR-PET scanner. In this work, some of these challenges were investigated, and an AC method based entirely on the MRI data obtained with a single dedicated sequence was developed and used for neurologic studies performed with the MR-PET human brain scanner prototype. The focus was on the problem of bone-air segmentation, selection of the linear attenuation coefficient for bone, and positioning of the radiofrequency coil. The impact of these factors on PET data quantification was studied in simulations and experimental measurements performed on the combined MR-PET scanner. A novel dual-echo ultrashort echo time (DUTE) MRI sequence was proposed for head imaging. Simultaneous MR-PET data were acquired, and the PET images reconstructed using the proposed DUTE MRI-based AC method were compared with the PET images that had been reconstructed using a CT-based AC method. Our data suggest that incorrectly accounting for the bone tissue attenuation can lead to large underestimations (>20%) of the radiotracer concentration in the cortex. Assigning a linear attenuation coefficient of 0.143 or 0.151 cm(-1) to bone tissue appears to give the best trade-off between bias and variability in the resulting images. Not identifying the internal air cavities introduces large overestimations (>20%) in adjacent structures. On the basis of these results, the segmented CT AC method was established as the silver standard for the segmented MRI-based AC method. For an integrated MR-PET scanner, in particular, ignoring the radiofrequency coil attenuation can cause large underestimations (i.e., images. Furthermore, the coil location in the PET field of view has to be accurately known. High-quality bone-air segmentation can be performed using the DUTE data. The PET images obtained using the DUTE MRI- and CT-based AC methods compare favorably in most of

Multimodal imaging utilising integrated MR-PET for human brain tumour assessment

International Nuclear Information System (INIS)

Neuner, Irene; Kaffanke, Joachim B.; Langen, Karl-Josef; Kops, Elena Rota; Tellmann, Lutz; Stoffels, Gabriele; Weirich, Christoph; Filss, Christian; Scheins, Juergen; Herzog, Hans; Shah, N. Jon

2012-01-01

The development of integrated magnetic resonance (MR)-positron emission tomography (PET) hybrid imaging opens up new horizons for imaging in neuro-oncology. In cerebral gliomas the definition of tumour extent may be difficult to ascertain using standard MR imaging (MRI) only. The differentiation of post-therapeutic scar tissue, tumour rests and tumour recurrence is challenging. The relationship to structures such as the pyramidal tract to the tumour mass influences the therapeutic neurosurgical approach. The diagnostic information may be enriched by sophisticated MR techniques such as diffusion tensor imaging (DTI), multiple-volume proton MR spectroscopic imaging (MRSI) and functional MRI (fMRI). Metabolic imaging with PET, especially using amino acid tracers such as 18 F-fluoroethyl-l-tyrosine (FET) or 11 C-l-methionine (MET) will indicate tumour extent and response to treatment. The new technologies comprising MR-PET hybrid systems have the advantage of providing comprehensive answers by a one-stop-job of 40-50 min. The combined approach provides data of different modalities using the same iso-centre, resulting in optimal spatial and temporal realignment. All images are acquired exactly under the same physiological conditions. We describe the imaging protocol in detail and provide patient examples for the different imaging modalities such as FET-PET, standard structural imaging (T1-weighted, T2-weighted, T1-weighted contrast agent enhanced), DTI, MRSI and fMRI. (orig.)

Multimodal imaging utilising integrated MR-PET for human brain tumour assessment

Energy Technology Data Exchange (ETDEWEB)

Neuner, Irene [Institute of Neuroscience and Medicine 4, INM 4, Juelich (Germany); RWTH Aachen University, Department of Psychiatry, Psychotherapy and Psychosomatics, Aachen (Germany); JARA-BRAIN-Translational Medicine, Aachen (Germany); Kaffanke, Joachim B. [Institute of Neuroscience and Medicine 4, INM 4, Juelich (Germany); MR-Transfer e.K., Wuppertal (Germany); Langen, Karl-Josef; Kops, Elena Rota; Tellmann, Lutz; Stoffels, Gabriele; Weirich, Christoph; Filss, Christian; Scheins, Juergen; Herzog, Hans [Institute of Neuroscience and Medicine 4, INM 4, Juelich (Germany); Shah, N. Jon [Institute of Neuroscience and Medicine 4, INM 4, Juelich (Germany); RWTH Aachen University, Department of Neurology, Aachen (Germany); JARA-BRAIN-Translational Medicine, Aachen (Germany)

2012-12-15

The development of integrated magnetic resonance (MR)-positron emission tomography (PET) hybrid imaging opens up new horizons for imaging in neuro-oncology. In cerebral gliomas the definition of tumour extent may be difficult to ascertain using standard MR imaging (MRI) only. The differentiation of post-therapeutic scar tissue, tumour rests and tumour recurrence is challenging. The relationship to structures such as the pyramidal tract to the tumour mass influences the therapeutic neurosurgical approach. The diagnostic information may be enriched by sophisticated MR techniques such as diffusion tensor imaging (DTI), multiple-volume proton MR spectroscopic imaging (MRSI) and functional MRI (fMRI). Metabolic imaging with PET, especially using amino acid tracers such as {sup 18}F-fluoroethyl-l-tyrosine (FET) or {sup 11}C-l-methionine (MET) will indicate tumour extent and response to treatment. The new technologies comprising MR-PET hybrid systems have the advantage of providing comprehensive answers by a one-stop-job of 40-50 min. The combined approach provides data of different modalities using the same iso-centre, resulting in optimal spatial and temporal realignment. All images are acquired exactly under the same physiological conditions. We describe the imaging protocol in detail and provide patient examples for the different imaging modalities such as FET-PET, standard structural imaging (T1-weighted, T2-weighted, T1-weighted contrast agent enhanced), DTI, MRSI and fMRI. (orig.)

Automated movement correction for dynamic PET/CT images: evaluation with phantom and patient data.

Science.gov (United States)

Ye, Hu; Wong, Koon-Pong; Wardak, Mirwais; Dahlbom, Magnus; Kepe, Vladimir; Barrio, Jorge R; Nelson, Linda D; Small, Gary W; Huang, Sung-Cheng

2014-01-01

Head movement during a dynamic brain PET/CT imaging results in mismatch between CT and dynamic PET images. It can cause artifacts in CT-based attenuation corrected PET images, thus affecting both the qualitative and quantitative aspects of the dynamic PET images and the derived parametric images. In this study, we developed an automated retrospective image-based movement correction (MC) procedure. The MC method first registered the CT image to each dynamic PET frames, then re-reconstructed the PET frames with CT-based attenuation correction, and finally re-aligned all the PET frames to the same position. We evaluated the MC method's performance on the Hoffman phantom and dynamic FDDNP and FDG PET/CT images of patients with neurodegenerative disease or with poor compliance. Dynamic FDDNP PET/CT images (65 min) were obtained from 12 patients and dynamic FDG PET/CT images (60 min) were obtained from 6 patients. Logan analysis with cerebellum as the reference region was used to generate regional distribution volume ratio (DVR) for FDDNP scan before and after MC. For FDG studies, the image derived input function was used to generate parametric image of FDG uptake constant (Ki) before and after MC. Phantom study showed high accuracy of registration between PET and CT and improved PET images after MC. In patient study, head movement was observed in all subjects, especially in late PET frames with an average displacement of 6.92 mm. The z-direction translation (average maximum = 5.32 mm) and x-axis rotation (average maximum = 5.19 degrees) occurred most frequently. Image artifacts were significantly diminished after MC. There were significant differences (Pdynamic brain FDDNP and FDG PET/CT scans could improve the qualitative and quantitative aspects of images of both tracers.

Quantification of {sup 18}F-FDG PET images using probabilistic brain atlas: clinical application in temporal lobe epilepsy patients

Energy Technology Data Exchange (ETDEWEB)

Kang, Keon Wook; Lee, Dong Soo; Cho, Jae Hoon; Lee, Jae Sung; Yeo, Jeong Seok; Lee, Sang Gun; Chung, June Key; Lee, Myung Chul [Seoul National Univ., Seoul (Korea, Republic of)

2000-07-01

A probabilistic atlas of the human brain (Statistical Probability Anatomical Maps: SPAM) was developed by the international consortium for brain mapping (ICBM). After calculating the counts in volume of interest (VOI) using the product of probability of SPAM images and counts in FDG images, asymmetric indexes(AI) were calculated and used for finding epileptogenic zones in temporal lobe epilepsy (TLE). FDG PET images from 28 surgically confirmed TLE patients and 12 age-matched controls were spatially normalized to the averaged brain MRI atlas of ICBM. The counts from normalized PET images were multiplied with the probability of 12 VOIs (superior temporal gyrus, middle temporal gyrus, inferior temporal gyrus, hippocampus, parahippocampal gyrus, and amygdala in each hemisphere) of SPAM images of Montreal Neurological Institute. Finally AI was calculated on each pair of VOI, and compared with visual assessment. If AI was deviated more than 2 standard deviation of normal controls, we considered epileptogenic zones were found successfully. The counts of VOIs in normal controls were symmetric (AI <6%, paired t-test p>0.05) except those of inferior temporal gyrus (p<0.01). AIs in 5 pairs of VOI excluding inferior temporal gyrus were deviated to one side in TLE (p<0.05). Lateralization was correct in 23/28 of patients by AI, but all of 28 were consistent with visual inspection. In 3 patients with normal AI was symmetric on visual inspection. In 2 patients falsely lateralized using AI, metabolism was also decreased visually on contra-lateral side. Asymmetric index obtained by the product of statistical probability anatomical map and FDG PET correlated well with visual assessment in TLE patients. SPAM is useful for quantification of VOIs in functional images.

Single photon image from PET with insertable collimator for boron neutron capture therapy

International Nuclear Information System (INIS)

Jung, Jooyoung; Suh, Tae Suk; Hong, Key Jo

2014-01-01

Boron neutron capture therapy (BNCT) is a radiation therapy technique for treating deep-seated brain tumors by irradiation with a thermal neutron in which boron-labelled low molecular weight compounds. Once completed, a single photon emission computed tomography (SPECT) scan is conducted to investigate for the region of therapy using an isotope exclusive to SPECT. In the case of an existing PET/SPECT combination system, at least two types of isotopes should be used for each scan with their purposes. Recently, researchers examined the effects of PET/SPECT dual modality on animal imaging systems. They reported that the PET/SPECT combination system was effective for simultaneous achievement of a single event and coincidence. The aim of our proposed system is to confirm the feasibility of extraction of two types of images from one PET module with an insertable collimator for brain tumor treatment during the BNCT. We attempted to acquire the PET and SPECT images simultaneously using only PET without an additional isotope. Single photon images were acquired using an insertable collimator on a PET detector

PET and Single-Photon Emission Computed Tomography in Brain Concussion.

Science.gov (United States)

Raji, Cyrus A; Henderson, Theodore A

2018-02-01

This article offers an overview of the application of PET and single photon emission computed tomography brain imaging to concussion, a type of mild traumatic brain injury and traumatic brain injury, in general. The article reviews the application of these neuronuclear imaging modalities in cross-sectional and longitudinal studies. Additionally, this article frames the current literature with an overview of the basic physics and radiation exposure risks of each modality. Copyright © 2017 Elsevier Inc. All rights reserved.

Inter-subject FDG PET Brain Networks Exhibit Multi-scale Community Structure with Different Normalization Techniques.

Science.gov (United States)

Sperry, Megan M; Kartha, Sonia; Granquist, Eric J; Winkelstein, Beth A

2018-07-01

Inter-subject networks are used to model correlations between brain regions and are particularly useful for metabolic imaging techniques, like 18F-2-deoxy-2-(18F)fluoro-D-glucose (FDG) positron emission tomography (PET). Since FDG PET typically produces a single image, correlations cannot be calculated over time. Little focus has been placed on the basic properties of inter-subject networks and if they are affected by group size and image normalization. FDG PET images were acquired from rats (n = 18), normalized by whole brain, visual cortex, or cerebellar FDG uptake, and used to construct correlation matrices. Group size effects on network stability were investigated by systematically adding rats and evaluating local network connectivity (node strength and clustering coefficient). Modularity and community structure were also evaluated in the differently normalized networks to assess meso-scale network relationships. Local network properties are stable regardless of normalization region for groups of at least 10. Whole brain-normalized networks are more modular than visual cortex- or cerebellum-normalized network (p network resolutions where modularity differs most between brain and randomized networks. Hierarchical analysis reveals consistent modules at different scales and clustering of spatially-proximate brain regions. Findings suggest inter-subject FDG PET networks are stable for reasonable group sizes and exhibit multi-scale modularity.

Brain PET and functional MRI: why simultaneously using hybrid PET/MR systems?

Science.gov (United States)

Cecchin, Diego; Palombit, Alessandro; Castellaro, Marco; Silvestri, Erica; Bui, Franco; Barthel, Henryk; Sabri, Osama; Corbetta, Maurizio; Bertoldo, Alessandra

2017-12-01

In the last 20 years growing attention has been devoted to multimodal imaging. The recent literature is rich of clinical and research studies that have been performed using different imaging modalities on both separate and integrated positron emission tomography (PET) and magnetic resonance (MR) scanners. However, today, hybrid PET/MR systems measure signals related to brain structure, metabolism, neurochemistry, perfusion, and neuronal activity simultaneously, i.e. in the same physiological conditions. A frequently raised question at meeting and symposia is: "Do we really need a hybrid PET/MR system? Are there any advantages over acquiring sequential and separate PET and MR scans?" The present paper is an attempt to answer these questions specifically in relation to PET combined with functional magnetic resonance imaging (fMRI) and arterial spin labeling. We searched (last update: June 2017) the databases PubMed, PMC, Google Scholar and Medline. We also included additional studies if they were cited in the selected articles. No language restriction was applied to the search, but the reviewed articles were all in English. Among all the retrieved articles, we selected only those performed using a hybrid PET/MR system. We found a total of 17 papers that were selected and discussed in three main groups according to the main radiopharmaceutical used: 18F-fluorodeoxyglucose (18F-FDG) (N.=8), 15O-water (15O-H2O) (N.=3) and neuroreceptors (N.=6). Concerning studies using 18F-FDG, simultaneous PET/fMRI revealed that global aspects of functional organization (e.g. graph properties of functional connections) are partially associated with energy consumption. There are remarkable spatial and functional similarities across modalities, but also discrepant findings. More work is needed on this point. There are only a handful of papers comparing blood flow measurements with PET 15O-H2O and MR arterial spin label (ASL) measures, and they show significant regional CBF differences

Imaging visual function of the human brain

International Nuclear Information System (INIS)

Marg, E.

1988-01-01

Imaging of human brain structure and activity with particular reference to visual function is reviewed along with methods of obtaining the data including computed tomographic (CT) scan, magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), and positron emission tomography (PET). The literature is reviewed and the potential for a new understanding of brain visual function is discussed. PET is reviewed from basic physical principles to the most recent visual brain findings with oxygen-15. It is shown that there is a potential for submillimeter localization of visual functions with sequentially different visual stimuli designed for the temporal separation of the responses. Single photon emission computed tomography (SPECT), a less expensive substitute for PET, is also discussed. MRS is covered from basic physical principles to the current state of the art of in vivo biochemical analysis. Future possible clinical applications are discussed. Improved understanding of the functional neural organization of vision and brain will open a window to maps and circuits of human brain function.119 references

Comparison of the diagnostic accuracy of PET/MRI to PET/CT-acquired FDG brain exams for seizure focus detection: a prospective study

Energy Technology Data Exchange (ETDEWEB)

Paldino, Michael J.; Jones, Jeremy Y.; Mahmood, Nadia; Sher, Andrew; Hayatghaibi, Shireen; Seghers, Victor [Texas Children' s Hospital, Department of Radiology, Houston, TX (United States); Yang, Erica [SimonMed Imaging, Department of Radiology, Scottsdale, AZ (United States); Zhang, Wei [Texas Children' s Hospital, Outcomes and Impact Service, Houston, TX (United States); Krishnamurthy, Ramkumar [Nationwide Children' s Hospital, Department of Radiology, Columbus, OH (United States)

2017-10-15

There is great interest in positron emission tomography (PET)/magnetic resonance (MR) as a clinical tool due to its capacity to provide diverse diagnostic information in a single exam. The goal of this exam is to compare the diagnostic accuracy of PET/MR-acquired [F-18]2-fluoro-2-deoxyglucose (FDG) brain exams to that of PET/CT with respect to identifying seizure foci in children with localization-related epilepsy. Institutional Review Board approval and informed consent were obtained for this Health Insurance Portability and Accountability Act-compliant, prospective study. All patients referred for clinical FDG-PET/CT exams of the brain at our institution for a diagnosis of localization-related epilepsy were prospectively recruited to undergo an additional FDG-PET acquisition on a tandem PET/MR system. Attenuation-corrected FDG images acquired at PET/MR and PET/CT were interpreted independently by five expert readers. Readers were blinded to the scanner used for acquisition and attenuation correction as well as all other clinical and imaging data. A Likert scale scoring system (1-5) was used to assess image quality. The locale of seizure origin determined at multidisciplinary epilepsy surgery work rounds was considered the reference standard. Non-inferiority testing for paired data was used to compare the diagnostic accuracy of PET/MR to that of PET/CT. The final study population comprised 35 patients referred for a diagnosis of localization-related epilepsy (age range: 2-19 years; median: 11 years; 21 males, 14 females). Image quality did not differ significantly between the two modalities. The accuracy of PET/MR was not inferior to that of PET/CT for localization of a seizure focus (P=0.017). The diagnostic accuracy of FDG-PET images acquired on a PET/MR scanner and generated using MR-based attenuation correction was not inferior to that of PET images processed by traditional CT-based correction. (orig.)

Comparison of the diagnostic accuracy of PET/MRI to PET/CT-acquired FDG brain exams for seizure focus detection: a prospective study

International Nuclear Information System (INIS)

Paldino, Michael J.; Jones, Jeremy Y.; Mahmood, Nadia; Sher, Andrew; Hayatghaibi, Shireen; Seghers, Victor; Yang, Erica; Zhang, Wei; Krishnamurthy, Ramkumar

2017-01-01

There is great interest in positron emission tomography (PET)/magnetic resonance (MR) as a clinical tool due to its capacity to provide diverse diagnostic information in a single exam. The goal of this exam is to compare the diagnostic accuracy of PET/MR-acquired [F-18]2-fluoro-2-deoxyglucose (FDG) brain exams to that of PET/CT with respect to identifying seizure foci in children with localization-related epilepsy. Institutional Review Board approval and informed consent were obtained for this Health Insurance Portability and Accountability Act-compliant, prospective study. All patients referred for clinical FDG-PET/CT exams of the brain at our institution for a diagnosis of localization-related epilepsy were prospectively recruited to undergo an additional FDG-PET acquisition on a tandem PET/MR system. Attenuation-corrected FDG images acquired at PET/MR and PET/CT were interpreted independently by five expert readers. Readers were blinded to the scanner used for acquisition and attenuation correction as well as all other clinical and imaging data. A Likert scale scoring system (1-5) was used to assess image quality. The locale of seizure origin determined at multidisciplinary epilepsy surgery work rounds was considered the reference standard. Non-inferiority testing for paired data was used to compare the diagnostic accuracy of PET/MR to that of PET/CT. The final study population comprised 35 patients referred for a diagnosis of localization-related epilepsy (age range: 2-19 years; median: 11 years; 21 males, 14 females). Image quality did not differ significantly between the two modalities. The accuracy of PET/MR was not inferior to that of PET/CT for localization of a seizure focus (P=0.017). The diagnostic accuracy of FDG-PET images acquired on a PET/MR scanner and generated using MR-based attenuation correction was not inferior to that of PET images processed by traditional CT-based correction. (orig.)

The effect of 18F-FDG-PET image reconstruction algorithms on the expression of characteristic metabolic brain network in Parkinson's disease.

Science.gov (United States)

Tomše, Petra; Jensterle, Luka; Rep, Sebastijan; Grmek, Marko; Zaletel, Katja; Eidelberg, David; Dhawan, Vijay; Ma, Yilong; Trošt, Maja

2017-09-01

To evaluate the reproducibility of the expression of Parkinson's Disease Related Pattern (PDRP) across multiple sets of 18F-FDG-PET brain images reconstructed with different reconstruction algorithms. 18F-FDG-PET brain imaging was performed in two independent cohorts of Parkinson's disease (PD) patients and normal controls (NC). Slovenian cohort (20 PD patients, 20 NC) was scanned with Siemens Biograph mCT camera and reconstructed using FBP, FBP+TOF, OSEM, OSEM+TOF, OSEM+PSF and OSEM+PSF+TOF. American Cohort (20 PD patients, 7 NC) was scanned with GE Advance camera and reconstructed using 3DRP, FORE-FBP and FORE-Iterative. Expressions of two previously-validated PDRP patterns (PDRP-Slovenia and PDRP-USA) were calculated. We compared the ability of PDRP to discriminate PD patients from NC, differences and correlation between the corresponding subject scores and ROC analysis results across the different reconstruction algorithms. The expression of PDRP-Slovenia and PDRP-USA networks was significantly elevated in PD patients compared to NC (palgorithms. PDRP expression strongly correlated between all studied algorithms and the reference algorithm (r⩾0.993, palgorithms varied within 0.73 and 0.08 of the reference value for PDRP-Slovenia and PDRP-USA, respectively. ROC analysis confirmed high similarity in sensitivity, specificity and AUC among all studied reconstruction algorithms. These results show that the expression of PDRP is reproducible across a variety of reconstruction algorithms of 18F-FDG-PET brain images. PDRP is capable of providing a robust metabolic biomarker of PD for multicenter 18F-FDG-PET images acquired in the context of differential diagnosis or clinical trials. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Optimized MLAA for quantitative non-TOF PET/MR of the brain

DEFF Research Database (Denmark)

Benoit, Didier; Ladefoged, Claes N.; Rezaei, Ahmadreza

2016-01-01

For quantitative tracer distribution in positron emission tomography, attenuation correction is essential. In a hybrid PET/CT system the CT images serve as a basis for generation of the attenuation map, but in PET/MR, the MR images do not have a similarly simple relationship with the attenuation...... map. Hence attenuation correction in PET/MR systems is more challenging. Typically either of two MR sequences are used: the Dixon or the ultra-short time echo (UTE) techniques. However these sequences have some well-known limitations. In this study, a reconstruction technique based on a modified...... and optimized non-TOF MLAA is proposed for PET/MR brain imaging. The idea is to tune the parameters of the MLTR applying some information from an attenuation image computed from the UTE sequences and a T1w MR image. In this MLTR algorithm, an [Formula: see text] parameter is introduced and optimized in order...

18F-FDG PET brain images as features for Alzheimer classification

Science.gov (United States)

Azmi, M. H.; Saripan, M. I.; Nordin, A. J.; Ahmad Saad, F. F.; Abdul Aziz, S. A.; Wan Adnan, W. A.

2017-08-01

2-Deoxy-2-[fluorine-18] fluoro-D-glucose (18F-FDG) Positron Emission Tomography (PET) imaging offers meaningful information for various types of diseases diagnosis. In Alzheimer's disease (AD), the hypometabolism of glucose which observed on the low intensity voxel in PET image may relate to the onset of the disease. The importance of early detection of AD is inevitable because the resultant brain damage is irreversible. Several statistical analysis and machine learning algorithm have been proposed to investigate the rate and the pattern of the hypometabolism. This study focus on the same aim with further investigation was performed on several hypometabolism pattern. Some pre-processing steps were implemented to standardize the data in order to minimize the effect of resolution and anatomical differences. The features used are the mean voxel intensity within the AD pattern mask, which derived from several z-score and FDR threshold values. The global mean voxel (GMV) and slice-based mean voxel (SbMV) intensity were observed and used as input to the neural network. Several neural network architectures were tested and compared to the nearest neighbour method. The highest accuracy equals to 0.9 and recorded at z-score ≤-1.3 with 1 node neural network architecture (sensitivity=0.81 and specificity=0.95) and at z-score ≤-0.7 with 10 nodes neural network (sensitivity=0.83 and specificity=0.94).

Functional brain imaging to investigate the higher brain dysfunction induced by diffuse brain injury

International Nuclear Information System (INIS)

Nariai, Tadashi; Inaji, Motoki; Ohno, Kikuo; Hiura, Mikio; Ishii, Kenji; Hosoda, Chihiro

2011-01-01

Higher brain dysfunction is the major problem of patients who recover from neurotrauma the prevents them from returning to their previous social life. Many such patients do not have focal brain damage detected with morphological imaging. We focused on studying the focal brain dysfunction that can be detected only with functional imaging with positron emission tomography (PET) in relation to the score of various cognition batteries. Patients who complain of higher brain dysfunction without apparent morphological cortical damage were recruited for this study. Thirteen patients with diffuse axonal injury (DAI) or cerebral concussion was included. They underwent a PET study to image glucose metabolism by 18 F-fluorodeoxyglucose (FDG), and central benodiazepine receptor (cBZD-R) (marker of neuronal body) by 11 C-flumazenil, together with cognition measurement by WAIS-R, WMS-R, and WCST etc. PET data were compared with age matched normal controls using statistical parametric mapping (SPM)2. DAI patients had a significant decrease in glucose matabolism and cBZD-R distribution in the cingulated cortex than normal controls. Patients diagnosed with concussion because of shorter consciousness disturbance also had abnormal FDG uptake and cBZD-R distribution. Cognition test scores were variable among patients. Degree of decreased glucose metabolism and cBZD-R distribution in the dominant hemishphere corresponded well to the severity of cognitive disturbance. PET molecular imaging was useful to depict focal cortical dysfunction of neurotrauma patients even when morphological change was not apparent. This method may be promising to clarify the pathophysiology of higher brain dysfunction of patients with diffuse axonal injury or chronic traumatic encephalopathy. (author)

The clinical utility of MR diffusion tensor imaging and spatially normalized PET to evaluate traumatic brain injury patients with memory and cognitive impairments

International Nuclear Information System (INIS)

Okumura, Ayumi; Yasokawa, Yuuto; Nakayama, Noriyuki; Miwa, Kazuhiro; Shinoda, Jun; Iwama, Toru

2005-01-01

We detected and compared abnormal brain areas using both MR diffusion tensor imaging (DTI) and easy Z score imaging system (eZIS) of fluorodeoxyglucose (FDG)-PET for traumatic brain injury patients with memory and cognitive impairments. Twenty normal subjects and eighteen diffuse axonal injury patients with memory and cognitive impairments were studied with DTI and eZIS of 18 F-FDG-PET. DTI contained fractional anisotorophy (FA) analysis and the tractography for the corpus callosum. After PET imaging was performed, statistical analysis using eZIS was undergone with followed processing steps, including smoothing, normalization and z transformation with respect to normal database. Z score map was superimposed on 3D MRI brain. Group analysis was performed using statistical parametric mapping (SPM). In diffuse axonal injury patients, the decline of FA was observed around the corpus callosum in comparison with normal subjects and the reduction of glucose metabolism was shown in the cingulated association. These results suggest that the reduction of metabolism within the cingulated cortex indicated deprived neuronal activation caused by the impaired neuronal connectivity that was revealed with DTI. Furthermore, the metabolic abnormalities within the cingulated cortex may be responsible for memory and cognitive impairments. DTI and spatially normalized PET have a role in neuroimaging interpretation for patients with memory and cognition impairments be cause its 3D better visualization allows objective and systematic investigation. (author)

Unilateral thalamic hypometabolism on FDG brain PET in patient with temporal lobe epilepsy

International Nuclear Information System (INIS)

Sager, Sait; Asa, Sertac; Uslu, Lebriz; Halac, Metin

2011-01-01

Interictal Brain 18 F fluorodeoxyglucose (FDG) Positron Emission Tomography (PET) imaging has been widely used for localizing the focus of a seizure. Hypometabolism in the extratemporal cortex on FDG-PET study is an important finding to localize seizure focus, which might be seen as ipsilateral, contralateral or bilateral thalamus hypometabolism in epileptic patients. In this case report, it is aimed to show ipsilateral thalamus hypometabolism on FDG PET brain study of a 24-year-old male patient with temporal lobe epilepsy. (author)

Oncology PET imaging

International Nuclear Information System (INIS)

Inubushi, Masayuki

2014-01-01

At the beginning of this article, likening medical images to 'Where is Waldo?' I indicate the concept of diagnostic process of PET/CT imaging, so that medical physics specialists could understand the role of each imaging modality and infer our distress for image diagnosis. Then, I state the present situation of PET imaging and the basics (e.g. health insurance coverage, clinical significance, principle, protocol, and pitfall) of oncology FDG-PET imaging which accounts for more than 99% of all clinical PET examinations in Japan. Finally, I would like to give a wishful prospect of oncology PET that will expand to be more cancer-specific in order to assess therapeutic effects of emerging molecular targeted drugs targeting the 'hallmarks of cancer'. (author)

Semi quantification study of [{sup 11}C]-(R)-PK11195 PET brain images in multiple sclerosis; Estudo da semiquantificacao de imagens PET cerebrais de [{sup 11}C]-(R)-PK11195 na esclerose multipla

Energy Technology Data Exchange (ETDEWEB)

Narciso, Lucas D.L.; Schuck, Phelipi N.; Dartora, Caroline M.; Matushita, Cristina S.; Becker, Jefferson; Silva, Ana M. Marques da, E-mail: lucas.narciso@acad.pucrs.br [Pontificia Universidade Catolica do Rio Grande do Sul (PUC-RS), Porto Alegre, RS (Brazil)

2016-07-01

PET brain images with [{sup 11}C]-(R)-PK11195 are being widely used to visualize microglial activation in vivo in neuro degenerative diseases, such as multiple sclerosis (MS). The aim of this study is to investigate the uptake behavior in justacortical and periventricular regions of [{sup 11}C]-(R)-PK11195 PET brain images reformatted in different time intervals by applying three methods, seeking method and time interval that significantly differentiate MS patients from healthy controls. Semi-quantitative SUV and uptake relative to a reference region methods were applied to PET images from different time intervals acquired from 10 patients with MS and 5 healthy controls. The results show significant SUV values difference (p = 0.01, 40 to 60 min) in justacortical and periventricular regions between groups and using the normalization method in which the uptake is relative to the mean concentration activity in the white matter (p <0.01, 10 to 60 min). (author)

Obsessive-compulsive disorder: advances in brain imaging

International Nuclear Information System (INIS)

Galli, Enrique

2000-01-01

In the past twenty years functional brain imaging has advanced to the point of tackling the differential diagnosis, prognosis and therapeutic response in Neurology and Psychiatry. Psychiatric disorders were rendered 'functional' a century ago; however nowadays they can be seen by means of brain imaging. Functional images in positron emission tomography (PET) and single photon emission tomography (NEUROSPET) show in non-invasive fashion the state of brain functioning. PET does this assessing glucose metabolism and NEUROSPET by putting cerebral blood flow in images. Prevalence of OCD is clearly low (2 to 3%), but comorbidity with depression, psychoses, bipolar disorder and schizophrenia is high. Furthermore, it is not infrequent with autism, attention disorder, tichotillomany, borderline personality disorders, in pathological compulsive spending, sexual compulsion and in pathological gambling, in tics, and in Gilles de la Tourette disorder, NEUROSPET and PET show hypoperfusion in both frontal lobes, in their prefrontal dorsolateral aspects, in their inferior zone and premotor cortex, with hyperperfusion in the posterior cingulum and hypoperfusion in basal ganglia (caudate nucleus). Cummings states that hyperactivity of the limbic system might be involved in OCD. Thus, brain imaging in OCD is a diagnostic aid, allows us to see clinical imagenological evolution and therapeutic response and, possibly, it is useful predict therapeutic response (Au)

Time series changes of MR/PET image of brain glucose metabolism in healthy subjects and alzheimer disease patients

International Nuclear Information System (INIS)

Tarusawa, Ayaka; Nihei, Mitsuyo; Tanaka, Mika; Fukami, Tadanori; Yuasa, Tetsuya; Wu, Jin; Kawasaki, Keiichi; Ishiwata, Kiichi; Ishii, Kenji

2010-01-01

Combination of morphological information by MRI and functional one by positron emission tomography (PET) was applied to quantitative evaluation of brain regional glucose metabolism in healthy subjects (HS) and Alzheimer disease patients (AD) and their individual aging changes were elucidated for ultimate purpose of computer-aided diagnosis. Subjects were: 5 AD patients (3M/2F, av. age 77.27 y), 14 ε4-carrying HS (EHS, 4M/10F, 71.3y) and 24 non-ε4-carrying HS (NEHS, 4M/20F, 70.21), where ε4 (apolipoprotein E type 4 gene allele)-carrying HS were reported to be prone to early AD and to tend to give increased brain atrophy incidence. Acquisitions of T1-weighted 3D MR and PET images were in 256 x 256 x(88-104) and x (90-100) voxels, respectively, with digitization level 16 bits, and were repeated 3 times in the time series of 21-38 months. Segmentation was performed with the MR imaging software SPM8 (Statistic Parametric Mapping: Metalab) to specify the regions of white/gray matters and cerebrospinal fluid (CSF). The binary MR and registered PET images were fused for comparison of glucose metabolism by SUVs (standardized uptake values) in gray matter of the three subject groups. Findings were: SUV in AD was markedly reduced; average time series changes per year were 0.11% in AD, -2.63% in EHS and 1.48% in NEHS; and statistical significance of the changes was between AD and NEHS, and between EHS and NEHS. Glucose metabolism by MR/PET can be thus used for a distinction of ε4-carrier and non-carrier in HS. (T.T.)

Positron Emission Tomography and Magnetic Resonance Imaging of the Brain in Fabry Disease

DEFF Research Database (Denmark)

Korsholm, Kirsten; Feldt-Rasmussen, Ulla; Granqvist, Henrik

2015-01-01

tomography (PET) and magnetic resonance imaging (MRI). PATIENTS: Forty patients with Fabry disease (14 males, 26 females, age at inclusion: 10-66 years, median: 39 years) underwent a brain F-18-FDG-PET-scan at inclusion, and 31 patients were followed with FDG-PET biannually for up to seven years. All...... patients (except one) had a brain MRI-scan at inclusion, and 34 patients were followed with MRI biannually for up to nine years. IMAGE ANALYSIS: The FDG-PET-images were inspected visually and analysed using a quantitative 3-dimensional stereotactic surface projection analysis (Neurostat). MRI images were...... also inspected visually and severity of white matter lesions (WMLs) was graded using a visual rating scale. RESULTS: In 28 patients brain-FDG-PET was normal; in 23 of these 28 patients brain MRI was normal--of the remaining five patients in this group, four patients had WMLs and one patient never had...

Simultaneous functional imaging using fPET and fMRI

Energy Technology Data Exchange (ETDEWEB)

Villien, Marjorie [CERMEP (France)

2015-05-18

Brain mapping of task-associated changes in metabolism with PET has been accomplished by subtracting scans acquired during two distinct static states. We have demonstrated that PET can provide truly dynamic information on cerebral energy metabolism using constant infusion of FDG and multiple stimuli in a single experiment. We demonstrate here that the functional PET (fPET-FDG) method accomplished simultaneously with fMRI, can enable the first direct comparisons in time, space and magnitude of hemodynamics and oxygen and glucose consumption. The imaging studies were performed on a 3T Tim-Trio MR scanner modified to support an MR-compatible BrainPET insert. Ten healthy subjects were included. The total PET acquisition and infusion time was 90 minutes. We did 3 blocks of right hand fingers tapping for 10 minutes at 30, 50 and 70 minutes after the beginning of the PET acquisition. ASL and BOLD imaging were acquired simultaneously during the motor paradigm. Changes in glucose utilization are easily observed as changes in the TAC slope of the PET data (FDG utilization rate) and in the derivative signal during motor stimuli in the activated voxels. PET and MRI (ASL, and BOLD) activations are largely colocalized but with very different statistical significance and temporal dynamic, especially in the ipsilateral side of the stimuli. This study demonstrated that motor activation can be measured dynamically during a single FDG PET scan. The complementary nature of fPET-FDG to fMRI capitalizes on the emerging technology of hybrid MR-PET scanners. fPET-FDG, combined with quantitative fMRI methods, allow us to simultaneously measure dynamic changes in glucose utilization and hemodynamic, addressing vital questions about neurovascular coupling.

Simultaneous functional imaging using fPET and fMRI

International Nuclear Information System (INIS)

Villien, Marjorie

2015-01-01

Brain mapping of task-associated changes in metabolism with PET has been accomplished by subtracting scans acquired during two distinct static states. We have demonstrated that PET can provide truly dynamic information on cerebral energy metabolism using constant infusion of FDG and multiple stimuli in a single experiment. We demonstrate here that the functional PET (fPET-FDG) method accomplished simultaneously with fMRI, can enable the first direct comparisons in time, space and magnitude of hemodynamics and oxygen and glucose consumption. The imaging studies were performed on a 3T Tim-Trio MR scanner modified to support an MR-compatible BrainPET insert. Ten healthy subjects were included. The total PET acquisition and infusion time was 90 minutes. We did 3 blocks of right hand fingers tapping for 10 minutes at 30, 50 and 70 minutes after the beginning of the PET acquisition. ASL and BOLD imaging were acquired simultaneously during the motor paradigm. Changes in glucose utilization are easily observed as changes in the TAC slope of the PET data (FDG utilization rate) and in the derivative signal during motor stimuli in the activated voxels. PET and MRI (ASL, and BOLD) activations are largely colocalized but with very different statistical significance and temporal dynamic, especially in the ipsilateral side of the stimuli. This study demonstrated that motor activation can be measured dynamically during a single FDG PET scan. The complementary nature of fPET-FDG to fMRI capitalizes on the emerging technology of hybrid MR-PET scanners. fPET-FDG, combined with quantitative fMRI methods, allow us to simultaneously measure dynamic changes in glucose utilization and hemodynamic, addressing vital questions about neurovascular coupling.

The study of automatic brain extraction of basal ganglia based on atlas of Talairach in 18F-FDG PET images

International Nuclear Information System (INIS)

Zuo Chantao; Guan Yihui; Zhao Jun; Lin Xiangtong; Wang Jian; Zhang Jiange; Zhang Lu

2005-01-01

Objective: To establish a method which can extract functional areas of the brain basal ganglia automatically. Methods: 18 F-fluorodeoxyglucose (FDG) PET images were spatial normalized to Talairach atlas space through two steps, image registration and image deformation. The functional areas were extracted from three dimension PET images based on the coordinate obtained from atlas; caudate and putamen were extracted and rendered, the grey value of the area was normalized by whole brain. Results: The normal ratio of left caudate head, body and tail were 1.02 ± 0.04, 0.92 ± 0.07 and 0.71 ± 0.03, the right were 0.98 ± 0.03, 0.87 ± 0.04 and 0.71 ± 0.01 respectively. The normal ratio of left and right putamen were 1.20 ± 0.06 and 1.20 ± 0.04. The mean grey value between left and right basal ganglia had no significant difference (P>0.05). Conclusion: The automatic functional area extracting method based on atlas of Talairach is feasible. (authors)

Qualitative and Quantitative Evaluation of Blob-Based Time-of-Flight PET Image Reconstruction in Hybrid Brain PET/MR Imaging

NARCIS (Netherlands)

Leemans, Eva L.; Kotasidis, Fotis; Wissmeyer, Michael; Garibotto, Valentina; Zaidi, Habib

2015-01-01

Many neurological diseases affect small structures in the brain and, as such, reliable visual evaluation and accurate quantification are required. Recent technological developments made the clinical use of hybrid positron emission tomography/magnetic resonance (PET/MR) systems possible, providing

Preliminary evaluation of a brain PET insertable to MRI

International Nuclear Information System (INIS)

Cho, Gyuseng; Choi, Yong; Lee, Jae Sung; An, Hyun Joon; Jung, Jin Ho; Park, Hyun Wook; Oh, Chang Hyun; Park, Kyeongjin; Lim, Kyung Taek; Cho, Minsik; Sul, Woo Suk; Kim, Hyoungtaek; Kim, Hyunduk

2014-01-01

There is a new trend of the medical image that diagnoses a brain disease as like Alzheimer dementia. The first qualified candidate is a PET-MRI fusion modality because MRI is a more powerful anatomic diagnosis tool than other modalities. In our study, in order to solve the high magnetic field from MRI, the development was consisted with four main items such as photo-sensor, PET scanner, MRI head-coil and attenuation correction algorithm development.

Preliminary evaluation of a brain PET insertable to MRI

Energy Technology Data Exchange (ETDEWEB)

Cho, Gyuseng [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 305-701 South (Korea, Republic of); Choi, Yong [Department of Electronic Engineering, Sogang University, Seoul, 121-742 South (Korea, Republic of); Lee, Jae Sung; An, Hyun Joon [Department of Nuclear Medicine, Seoul National University, Seoul, 110-744 South (Korea, Republic of); Jung, Jin Ho [Department of Electronic Engineering, Sogang University, Seoul, 121-742 South (Korea, Republic of); Park, Hyun Wook; Oh, Chang Hyun; Park, Kyeongjin; Lim, Kyung Taek; Cho, Minsik [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 305-701 South (Korea, Republic of); Sul, Woo Suk [National NanoFab Center, Deajeon, 305-806 South (Korea, Republic of); Kim, Hyoungtaek; Kim, Hyunduk [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 305-701 South (Korea, Republic of)

2014-07-29

There is a new trend of the medical image that diagnoses a brain disease as like Alzheimer dementia. The first qualified candidate is a PET-MRI fusion modality because MRI is a more powerful anatomic diagnosis tool than other modalities. In our study, in order to solve the high magnetic field from MRI, the development was consisted with four main items such as photo-sensor, PET scanner, MRI head-coil and attenuation correction algorithm development.

PET/CT imaging of striatal dopamine transporters in a newborn piglet model of hypoxic-ischemic brain injury

International Nuclear Information System (INIS)

Zhang Yanfen; Wang Xiaoming; Wang Xiaoyu; Cao Li; Guo Qiyong

2013-01-01

Objective: To investigate changes of striatal DAT following hypoxic ischemic (HI) brain injury in newborn piglets using 11 C-N-2-carbomethoxy-3-(4-fluorophenyl)-tropane (CFT) PET/CT, and to evaluate the value of 11 C-CFT PET/CT in brain injury. Methods: Newborn piglets with HI brain injury (n=20) were taken as a model group,and five piglets were used as a control group. Radioligand 11 C-CFT (55.5-74.0 MBq) was injected through the jugular vein, and PET/CT imaging was performed to observe the changes of striatal DAT in newborn piglets. The ST/occipital lobe (OC) ratio was calculated. Model group was divided into 0-6 h, 20-24 h, 44-48 h and 68-72 h sub-groups after HI in accordance with the imaging time. The piglets were sacrificed immediately after 11 C-CFT PET/CT scanning, and then the brains were removed for pathological analysis. Data analysis was performed with one-way analysis of variance and Pearson linear correlation analysis. Results: After intravenous injection of 11 C-CFT, the radioactivity accumulation in cortical, striatum, and cerebellum was shown clearly in the control and model groups. The radioactivity accumulation was lower in the white matter. The radioactivity in cortical and cerebellum exhibited decreased with time, while the striatum was still clear. After HI, the ST/OC activity ratio in the striatum was initially increased, and the ratio of 0-6 h group (1.34 ± 0.04) was statistically significant compared with that of the control group (1.18 ± 0.06; F=4.658, P<0.05), followed by a gradual decrease. ST/OC ratios of other HI subgroups were 1.27 ±0.01, 1.27 ±0.10 and 1.18 ±0.05, respectively. There was a positive correlation between the number of DAT positive neurons ((13 ± 3), (13 ± 4), (8 ±3) and (4 ±4)/high power field) and 11 C-CFT ST/OC activity ratios (r=0.844, P<0.05). Conclusion: 11 C-CFT PET/CT study can accurately reflect the changes of DAT in the striatum, and the amount of DAT is related to the severity of the ischemic insult

Brain {sup 18}F-FDG PET-MRI co registration: iconographic essay;PET-RM neurologico com FDG-{sup 18}F: ensaio iconografico

Energy Technology Data Exchange (ETDEWEB)

Cavalcanti Filho, Jose Leite Gondim; Machado Neto, Luiz de Souza, E-mail: leite_jose@yahoo.co [Multi Imagem PET, Rio de Janeiro, RJ (Brazil); Fonseca, Lea Mirian Barbosa da; Gasparetto, Emerson Leandro [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); Domingues, Romeu Cortes; Domingues, Roberto Cortes [Clinica de Diagnostico por Imagem (CDPI), Rio de Janeiro, RJ (Brazil)

2010-05-15

The combination of positron emission tomography (PET) with magnetic resonance imaging (MRI) has been the subject of several studies in recent years. Positron emission tomography is the most sensitive and specific imaging modality in the detection of metabolic changes, but presents limited spatial resolution. On the other hand, MRI presents a significant spatial resolution, besides evaluating soft tissues signal intensity with excellent contrast resolution. The present iconographic essay is aimed at demonstrating the potential clinical application of PET/MRI co registration. The studies were performed in a dedicated PET unit with {sup 18}F-fluorodeoxyglucose (FDG) as radiopharmaceutical and co registered with 1.5 T or 3 T brain MRI. The brain images fusion software presents an already well-established accuracy, so a significant synergy between a functional PET study and an excellent MRI anatomical detail is achieved. The most attractive clinical applications of this approach are the following: epileptogenic zone assessment in patients refractory to drug therapy, identification of patients with cognitive impairment at higher risk for progression to dementia and differentiation of dementias and Parkinsonian syndromes. (author)

Imaging and PET - PET/CT imaging

International Nuclear Information System (INIS)

Von Schulthess, G.K.; Hany, Th.F.

2008-01-01

PET/CT has grown because the lack of anatomic landmarks in PET makes 'hardware-fusion' to anatomic cross-sectional data extremely useful. Addition of CT to PET improves specificity, but also sensitivity, and adding PET to CT adds sensitivity and specificity in tumor imaging. The synergistic advantage of adding CT is that the attenuation correction needed for PET data can also be derived from the CT data. This makes PET-CT 25-30% faster than PET alone, leading to higher patient throughput and a more comfortable examination for patients typically lasting 20 minutes or less. FDG-PET-CT appears to provide relevant information in the staging and therapy monitoring of many tumors, such as lung carcinoma, colorectal cancer, lymphoma, gynaecological cancers, melanoma and many others, with the notable exception of prostatic cancer. for this cancer, choline derivatives may possibly become useful radiopharmaceuticals. The published literature on the applications of FDG-PET-CT in oncology is still limited but several designed studies have demonstrated the benefits of PET-CT. (authors)

Technical considerations on scanning and image analysis for amyloid PET in dementia

International Nuclear Information System (INIS)

Akamatsu, Go; Ohnishi, Akihito; Aita, Kazuki; Ikari, Yasuhiko; Senda, Michio; Yamamoto, Yasuji

2017-01-01

Brain imaging techniques, such as computed tomography (CT), magnetic resonance imaging (MRI), single photon emission computed tomography (SPECT), and positron emission tomography (PET), can provide essential and objective information for the early and differential diagnosis of dementia. Amyloid PET is especially useful to evaluate the amyloid-β pathological process as a biomarker of Alzheimer's disease. This article reviews critical points about technical considerations on the scanning and image analysis methods for amyloid PET. Each amyloid PET agent has its own proper administration instructions and recommended uptake time, scan duration, and the method of image display and interpretation. In addition, we have introduced general scanning information, including subject positioning, reconstruction parameters, and quantitative and statistical image analysis. We believe that this article could make amyloid PET a more reliable tool in clinical study and practice. (author)

Technical Considerations on Scanning and Image Analysis for Amyloid PET in Dementia.

Science.gov (United States)

Akamatsu, Go; Ohnishi, Akihito; Aita, Kazuki; Ikari, Yasuhiko; Yamamoto, Yasuji; Senda, Michio

2017-01-01

Brain imaging techniques, such as computed tomography (CT), magnetic resonance imaging (MRI), single photon emission computed tomography (SPECT), and positron emission tomography (PET), can provide essential and objective information for the early and differential diagnosis of dementia. Amyloid PET is especially useful to evaluate the amyloid-β pathological process as a biomarker of Alzheimer's disease. This article reviews critical points about technical considerations on the scanning and image analysis methods for amyloid PET. Each amyloid PET agent has its own proper administration instructions and recommended uptake time, scan duration, and the method of image display and interpretation. In addition, we have introduced general scanning information, including subject positioning, reconstruction parameters, and quantitative and statistical image analysis. We believe that this article could make amyloid PET a more reliable tool in clinical study and practice.

Spatio-temporal diffusion of dynamic PET images

International Nuclear Information System (INIS)

Tauber, C; Chalon, S; Guilloteau, D; Stute, S; Buvat, I; Chau, M; Spiteri, P

2011-01-01

Positron emission tomography (PET) images are corrupted by noise. This is especially true in dynamic PET imaging where short frames are required to capture the peak of activity concentration after the radiotracer injection. High noise results in a possible bias in quantification, as the compartmental models used to estimate the kinetic parameters are sensitive to noise. This paper describes a new post-reconstruction filter to increase the signal-to-noise ratio in dynamic PET imaging. It consists in a spatio-temporal robust diffusion of the 4D image based on the time activity curve (TAC) in each voxel. It reduces the noise in homogeneous areas while preserving the distinct kinetics in regions of interest corresponding to different underlying physiological processes. Neither anatomical priors nor the kinetic model are required. We propose an automatic selection of the scale parameter involved in the diffusion process based on a robust statistical analysis of the distances between TACs. The method is evaluated using Monte Carlo simulations of brain activity distributions. We demonstrate the usefulness of the method and its superior performance over two other post-reconstruction spatial and temporal filters. Our simulations suggest that the proposed method can be used to significantly increase the signal-to-noise ratio in dynamic PET imaging.

Specification and estimation of sources of bias affecting neurological studies in PET/MR with an anatomical brain phantom

Energy Technology Data Exchange (ETDEWEB)

Teuho, J., E-mail: jarmo.teuho@tyks.fi [Turku PET Centre, Turku (Finland); Johansson, J. [Turku PET Centre, Turku (Finland); Linden, J. [Turku PET Centre, Turku (Finland); Department of Mathematics and Statistics, University of Turku, Turku (Finland); Saunavaara, V.; Tolvanen, T.; Teräs, M. [Turku PET Centre, Turku (Finland)

2014-01-11

Selection of reconstruction parameters has an effect on the image quantification in PET, with an additional contribution from a scanner-specific attenuation correction method. For achieving comparable results in inter- and intra-center comparisons, any existing quantitative differences should be identified and compensated for. In this study, a comparison between PET, PET/CT and PET/MR is performed by using an anatomical brain phantom, to identify and measure the amount of bias caused due to differences in reconstruction and attenuation correction methods especially in PET/MR. Differences were estimated by using visual, qualitative and quantitative analysis. The qualitative analysis consisted of a line profile analysis for measuring the reproduction of anatomical structures and the contribution of the amount of iterations to image contrast. The quantitative analysis consisted of measurement and comparison of 10 anatomical VOIs, where the HRRT was considered as the reference. All scanners reproduced the main anatomical structures of the phantom adequately, although the image contrast on the PET/MR was inferior when using a default clinical brain protocol. Image contrast was improved by increasing the amount of iterations from 2 to 5 while using 33 subsets. Furthermore, a PET/MR-specific bias was detected, which resulted in underestimation of the activity values in anatomical structures closest to the skull, due to the MR-derived attenuation map that ignores the bone. Thus, further improvements for the PET/MR reconstruction and attenuation correction could be achieved by optimization of RAMLA-specific reconstruction parameters and implementation of bone to the attenuation template. -- Highlights: • Comparison between PET, PET/CT and PET/MR was performed with a novel brain phantom. • The performance of reconstruction and attenuation correction in PET/MR was studied. • A recently developed brain phantom was found feasible for PET/MR imaging. • Contrast reduction

Three-dimensional reconstruction of functional brain images

International Nuclear Information System (INIS)

Inoue, Masato; Shoji, Kazuhiko; Kojima, Hisayoshi; Hirano, Shigeru; Naito, Yasushi; Honjo, Iwao

1999-01-01

We consider PET (positron emission tomography) measurement with SPM (Statistical Parametric Mapping) analysis to be one of the most useful methods to identify activated areas of the brain involved in language processing. SPM is an effective analytical method that detects markedly activated areas over the whole brain. However, with the conventional presentations of these functional brain images, such as horizontal slices, three directional projection, or brain surface coloring, makes understanding and interpreting the positional relationships among various brain areas difficult. Therefore, we developed three-dimensionally reconstructed images from these functional brain images to improve the interpretation. The subjects were 12 normal volunteers. The following three types of images were constructed: routine images by SPM, three-dimensional static images, and three-dimensional dynamic images, after PET images were analyzed by SPM during daily dialog listening. The creation of images of both the three-dimensional static and dynamic types employed the volume rendering method by VTK (The Visualization Toolkit). Since the functional brain images did not include original brain images, we synthesized SPM and MRI brain images by self-made C++ programs. The three-dimensional dynamic images were made by sequencing static images with available software. Images of both the three-dimensional static and dynamic types were processed by a personal computer system. Our newly created images showed clearer positional relationships among activated brain areas compared to the conventional method. To date, functional brain images have been employed in fields such as neurology or neurosurgery, however, these images may be useful even in the field of otorhinolaryngology, to assess hearing and speech. Exact three-dimensional images based on functional brain images are important for exact and intuitive interpretation, and may lead to new developments in brain science. Currently, the surface

Three-dimensional reconstruction of functional brain images

Energy Technology Data Exchange (ETDEWEB)

Inoue, Masato; Shoji, Kazuhiko; Kojima, Hisayoshi; Hirano, Shigeru; Naito, Yasushi; Honjo, Iwao [Kyoto Univ. (Japan)

1999-08-01

We consider PET (positron emission tomography) measurement with SPM (Statistical Parametric Mapping) analysis to be one of the most useful methods to identify activated areas of the brain involved in language processing. SPM is an effective analytical method that detects markedly activated areas over the whole brain. However, with the conventional presentations of these functional brain images, such as horizontal slices, three directional projection, or brain surface coloring, makes understanding and interpreting the positional relationships among various brain areas difficult. Therefore, we developed three-dimensionally reconstructed images from these functional brain images to improve the interpretation. The subjects were 12 normal volunteers. The following three types of images were constructed: routine images by SPM, three-dimensional static images, and three-dimensional dynamic images, after PET images were analyzed by SPM during daily dialog listening. The creation of images of both the three-dimensional static and dynamic types employed the volume rendering method by VTK (The Visualization Toolkit). Since the functional brain images did not include original brain images, we synthesized SPM and MRI brain images by self-made C++ programs. The three-dimensional dynamic images were made by sequencing static images with available software. Images of both the three-dimensional static and dynamic types were processed by a personal computer system. Our newly created images showed clearer positional relationships among activated brain areas compared to the conventional method. To date, functional brain images have been employed in fields such as neurology or neurosurgery, however, these images may be useful even in the field of otorhinolaryngology, to assess hearing and speech. Exact three-dimensional images based on functional brain images are important for exact and intuitive interpretation, and may lead to new developments in brain science. Currently, the surface

Whole-body biodistribution and brain PET imaging with [{sup 18}F]AV-45, a novel amyloid imaging agent - a pilot study

Energy Technology Data Exchange (ETDEWEB)

Lin, K.-J. [Department of Nuclear Medicine and Molecular Imaging Center, Chang Gung Memorial Hospital, Taiwan (China); Department of Medical Imaging and Radiological Sciences, Chang Gung University, Taiwan (China); Hsu, W.-C. [Department of Neurology, Chang Gung Memorial Hospital, Taiwan (China); Hsiao, I.-T.; Wey, S.-P. [Department of Nuclear Medicine and Molecular Imaging Center, Chang Gung Memorial Hospital, Taiwan (China); Department of Medical Imaging and Radiological Sciences, Chang Gung University, Taiwan (China); Jin, L.-W. [M.I.N.D. Institute and Department of Pathology, University of California, Davis, CA (United States); Skovronsky, Daniel [Avid Radiopharmaceuticals, Inc., Philadelphia, PA (United States); Wai, Y.-Y. [Department of Nuclear Medicine and Molecular Imaging Center, Chang Gung Memorial Hospital, Taiwan (China); Department of Radiology, Chang Gung Memorial Hospital, Taiwan (China); Chang, H.-P.; Lo, C.-W.; Yao, C.H.; Yen, T.-C. [Department of Nuclear Medicine and Molecular Imaging Center, Chang Gung Memorial Hospital, Taiwan (China); Kung, M.-P. [Department of Nuclear Medicine and Molecular Imaging Center, Chang Gung Memorial Hospital, Taiwan (China); Department of Radiology, University of Pennsylvania, Philadelphia, PA (United States)

2010-05-15

Purpose: The compound (E)-4-(2-(6-(2-(2-(2-{sup 18}F-fluoroethoxy)ethoxy)ethoxy) pyridin-3-yl)vinyl)-N-methylbenzenamine ([{sup 18}F]AV-45) is a novel radiopharmaceutical capable of selectively binding to {beta}-amyloid (A{beta}) plaques. This pilot study reports the safety, biodistribution, and radiation dosimetry of [{sup 18}F]AV-45 in human subjects. Methods: In vitro autoradiography and fluorescent staining of postmortem brain tissue from patients with Alzheimer's disease (AD) and cognitively healthy subjects were performed to assess the specificity of the tracer. Biodistribution was assessed in three healthy elderly subjects (mean age: 60.0{+-}5.2 years) who underwent 3-h whole-body positron emission tomography (PET)/computed tomographic (CT) scans after a bolus injection of 381.9{+-}13.9 MBq of [{sup 18}F]AV-45. Another six subjects (three AD patients and three healthy controls, mean age: 67.7{+-}13.6 years) underwent brain PET studies. Source organs were delineated on PET/CT. All subjects underwent magnetic resonance imaging (MRI) for obtaining structural information. Results: In vitro autoradiography revealed exquisitely high specific binding of [{sup 18}F]AV-45 to postmortem AD brain sections, but not to the control sections. There were no serious adverse events throughout the study period. The peak uptake of the tracer in the brain was 5.12{+-}0.41% of the injected dose. The highest absorbed organ dose was to the gallbladder wall (184.7{+-}78.6 {mu}Gy/MBq, 4.8 h voiding interval). The effective dose equivalent and effective dose values for [{sup 18}F]AV-45 were 33.8{+-}3.4 {mu}Sv/MBq and 19.3{+-}1.3 {mu}Sv/MBq, respectively. Conclusion: [{sup 18}F]AV-45 binds specifically to A{beta} in vitro, and is a safe PET tracer for studying A{beta} distribution in human brain. The dosimetry is suitable for clinical and research application.

New perspective in high tech radiotherapy planning using PET/CT images (Radiation oncologist's view on PET/CT usage)

International Nuclear Information System (INIS)

Hadjieva, T.; Bildirev, N.; Koleva, I.; Zahariev, Z.; Vasileva, V.; Encheva, E.; Sultanov, B.

2010-01-01

Biological images provided by 18F-FDG PET in combination with structural X ray picture currently offer the most accurate available information on tumour staging, curative antitumour effect for prognosis, impairment of organ function after treatment, as well as primary tumour detection in unknown primary metastatic disease. The authors as radiation oncologists critically have analyzed numerous clinical trials and two guidelines to prove PET/ CT benefit in radiotherapy practice. At present they found lack of scientific evidence to confirm that patient outcomes are superior as a result of the use of PET in RT planning. PET/CT offers a best image for tumour delineation only in some cases of lung cancer, mediastinal lymph nodes and malignant lymphomas. 11C methionin PET adds additional information on postoperative MRI image for brain tumours. Inflammation as postradiation phenomenon, as well as physiological organ movements leads to false-positive PET signal. High tech radiotherapy methods require delineation on precise images given after multidisciplinary team expertise - a practice that is possible only in clinical trials, These unsolved problems have raised many ethical challenges in medical, scientific and social aspect, if wide and routine use of FDG-PET u PET/CT is advocated. (authors)

Semi-automatic ROI placement system for analysis of brain PET images based on elastic model. Application to diagnosis of Alzheimer's disease

International Nuclear Information System (INIS)

Ohyama, Masashi; Mishina, Masahiro; Kitamura, Shin; Katayama, Yasuo; Senda, Michio; Tanizaki, Naoki; Ishii, Kenji

2000-01-01

PET with 18F-fluorodeoxyglucose (FDG) is a useful technique to image cerebral glucose metabolism and to detect patients with Alzheimer's disease in the early stage, in which characteristic temporoparietal hypometabolism is visualized. We have developed a new system, in which the standard brain ROI atlas made of networks of segments is elastically transformed to match the subject brain images, so that standard ROIs defined on the segments are placed on the individual brain images and are used to measure radioactivity over each brain region. We applied this methods to Alzheimer's disease. This method was applied to the images of 10 normal subjects (ages 55 +/- 12) and 21 patients clinically diagnosed as Alzheimer's disease (age 61 +/- 10). The FDG uptake reflecting glucose metabolism was evaluated with SUV, i.e. decay corrected radioactivity divided by injected dose per body weight in (Bq/ml)/(Bq/g). The system worked all right in every subject including those with extensive hypometabolism. Alzheimer patients showed markedly lower in the parietal cortex (4.0-4.1). When the threshold value of FDG uptake in the parietal lobe was set as 5 (Bq/ml)/(Bq/g), we could discriminate the patients with Alzheimer's disease from the normal subjects. The sensitivity was 86% and the specificity was 90%. This system can assist diagnosis of FDG images and may be useful for treating data of a large number of subjects; e.g. when PET is applied to health screening. (author)

A small animal PET based on GAPDs and charge signal transmission approach for hybrid PET-MR imaging

Energy Technology Data Exchange (ETDEWEB)

Kang, Jihoon; Choi, Yong; Hong, Key Jo; Hu, Wei; Jung, Jin Ho; Huh, Yoonsuk [Department of Electronic Engineering, Sogang University, 1 Shinsu-Dong, Mapo-Gu, Seoul 121-742 (Korea, Republic of); Kim, Byung-Tae, E-mail: ychoi.image@gmail.com [Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-Dong, Gangnam-Gu, Seoul 135-710 (Korea, Republic of)

2011-08-15

Positron emission tomography (PET) employing Geiger-mode avalanche photodiodes (GAPDs) and charge signal transmission approach was developed for small animal imaging. Animal PET contained 16 LYSO and GAPD detector modules that were arranged in a 70 mm diameter ring with an axial field of view of 13 mm. The GAPDs charge output signals were transmitted to a preamplifier located remotely using 300 cm flexible flat cables. The position decoder circuits (PDCs) were used to multiplex the PET signals from 256 to 4 channels. The outputs of the PDCs were digitized and further-processed in the data acquisition unit. The cross-compatibilities of the PET detectors and MRI were assessed outside and inside the MRI. Experimental studies of the developed full ring PET were performed to examine the spatial resolution and sensitivity. Phantom and mouse images were acquired to examine the imaging performance. The mean energy and time resolution of the PET detector were 17.6% and 1.5 ns, respectively. No obvious degradation on PET and MRI was observed during simultaneous PET-MRI data acquisition. The measured spatial resolution and sensitivity at the CFOV were 2.8 mm and 0.7%, respectively. In addition, a 3 mm diameter line source was clearly resolved in the hot-sphere phantom images. The reconstructed transaxial PET images of the mouse brain and tumor displaying the glucose metabolism patterns were imaged well. These results demonstrate GAPD and the charge signal transmission approach can allow the development of high performance small animal PET with improved MR compatibility.

Clinical PET/MR Imaging in Dementia and Neuro-Oncology

DEFF Research Database (Denmark)

Henriksen, Otto M.; Marner, Lisbeth; Law, Ian

2016-01-01

The introduction of hybrid PET/MRI systems allows simultaneous multimodality image acquisition of high technical quality. This technique is well suited for the brain, and particularly in dementia and neuro-oncology. In routine use combinations of well-established MRI sequences and PET tracers....../MRI using [18F]-fluoro-ethyl-tyrosine (FET) also abide to the expectations of the adaptive and versatile diagnostic tool necessary in neuro-oncology covering both simple 20 min protocols for routine treatment surveillance and complicated 90 min brain and spinal cord protocols in pediatric neuro...

Evaluation of the Dopamine Hypothesis of ADHD with PET Brain Imaging

International Nuclear Information System (INIS)

Swanson, James

2010-01-01

The Dopamine (DA) Hypothesis of ADHD (Wender, 1971; Levy, 1990) suggests that abnormalities in the synaptic mechanisms of DA transmission may be disrupted, and specific abnormalities in DA receptors and DA transporters (DAT) have been proposed (see Swanson et al, 1998). Early studies with small samples (e.g., n = 6, Dougherty et al, 1999) used single photon emission tomography (SPECT) and the radioligand (123I Altropane) to test a theory that ADHD may be caused by an over expression of DAT and reported 'a 70% increase in age-corrected dopamine transporter density in patients with attention deficit hyperactivity disorder compared with healthy controls' and suggested that treatment with stimulant medication decreased DAT density in ADHD patients and corrected an underlying abnormality (Krause et al, 2000). The potential importance of these findings was noted by Swanson (1999): 'If true, this is a major finding and points the way for new investigations of the primary pharmacological treatment for ADHD (with the stimulant drugs - e.g., methylphenidate), for which the dopamine transporter is the primary site of action. The potential importance of this finding demands special scrutiny'. This has been provided over the past decade using Positron Emission Tomography (PET). Brain imaging studies were conducted at Brookhaven National Laboratory (BNL) in a relatively large sample of stimulant-naive adults assessed for DAT (11C cocaine) density and DA receptors (11C raclopride) availability. These studies (Volkow et al, 2007; Volkow et al, 2009) do not confirm the hypothesis of increased DAT density and suggest the opposite (i.e., decreased rather than increased DAT density), and follow-up after treatment (Wang et al, 2010) does not confirm the hypothesis that therapeutic doses of methylphenidate decrease DAT density and suggests the opposite (i.e., increased rather than decreased DAT density). The brain regions implicated by these PET imaging studies also suggest that a

Non-oncological positron emission tomography (PET): brain imaging; La tomographie par emission de positons (TEP) hors oncologie: l'exploration du cerveau

Energy Technology Data Exchange (ETDEWEB)

Lomena, F. [Centro de Diagnostico por la imagen (CDIC), Hospital Clinic, Servicio de medicina nuclear, Barcelona (Spain)

2008-10-15

Positron emission tomography (PET) allows evaluation of the central nervous system function. Imaging of regional cerebral blood flow and metabolism, and of several neurotransmission systems may be obtained using PET. PET quantification is accurate and has good test-retest reliability. For research purposes, PET has been used to study brain physiology, to explore neurological and psychiatric diseases pathophysiology and for the new drugs research and development. F.D.G. is the only PET radioligand with clinical application. Following criteria of evidence-based medicine, the clinical indications of F.D.G.-PET are: evaluation of treated gliomas, pre surgical study of partial refractory epilepsy and diagnosis of Alzheimer's disease when it is impossible to differentiate clinically from fronto-temporal dementia.

Simulating effects of brain atrophy in longitudinal PET imaging with an anthropomorphic brain phantom

DEFF Research Database (Denmark)

Jonasson, L S; Axelsson, J; Riklund, K

2017-01-01

In longitudinal positron emission tomography (PET), the presence of volumetric changes over time can lead to an overestimation or underestimation of the true changes in the quantified PET signal due to the partial volume effect (PVE) introduced by the limited spatial resolution of existing PET...... cameras and reconstruction algorithms. Here, a 3D-printed anthropomorphic brain phantom with attachable striata in three sizes was designed to enable controlled volumetric changes. Using a method to eliminate the non-radioactive plastic wall, and manipulating BP levels by adding different number of events...... from list-mode acquisitions, we investigated the artificial volume dependence of BP due to PVE, and potential bias arising from varying BP. Comparing multiple reconstruction algorithms we found that a high-resolution ordered-subsets maximization algorithm with spatially variant point-spread function...

Evaluation of {sup 18}F-BCPP-EF for mitochondrial complex 1 imaging in the brain of conscious monkeys using PET

Energy Technology Data Exchange (ETDEWEB)

Tsukada, Hideo; Ohba, Hiroyuki; Kanazawa, Masakatsu; Kakiuchi, Takeharu; Harada, Norihiro [Hamamatsu Photonics K.K., Central Research Laboratory, Hamamatsu, Shizuoka (Japan)

2014-04-15

We have reported on the development of a novel PET probe, {sup 18}F-2-tert-butyl-4-chloro-5-{6-[2-(2-fluoroethoxy)-ethoxy] -pyridin-3-ylmethoxy}-2H-pyridazin-3-one ({sup 18}F-BCPP-EF), for quantitative imaging of mitochondrial complex 1 (MC-1) activity in the brain of the living rat. For clinical application in humans, translational research in the monkey was conducted. PET measurements with {sup 18}F-BCPP-EF were performed in young and old monkeys (Macaca mulatta) in a conscious state with arterial blood sampling. The binding specificity of {sup 18}F-BCPP-EF was evaluated with rotenone, a specific MC-1 inhibitor, in young animals. The binding (total distribution volume, V{sub T}) of {sup 18}F-BCPP-EF was calculated using Logan graphical analysis, and one-tissue compartment model (1-TC) and two-tissue compartment model (2-TC) analyses using a metabolite-corrected plasma input function. F-BCPP-EF was rapidly taken up into the brain just after intravenous injection, peaked between 10 and 20 min after injection, and was then gradually eliminated. The 2-TC analysis provided a better fit than the 1-TC analysis, and the V{sub T} values from the 2-TC analysis correlated well with those from the Logan plot. With predosing with rotenone, {sup 18}F-BCPP-EF showed a higher uptake peak in the brain, followed by more rapid elimination thereafter than in the vehicle condition, resulting in significant reductions in 2-TC V{sub T} values in all regions. In old animals, the kinetics of {sup 18}F-BCPP-EF were slightly slower with lower peak levels than in young animals, resulting age-related reductions in {sup 18}F-BCPP-EF binding in all brain regions. The present study demonstrated that {sup 18}F-BCPP-EF may be a potential PET probe for quantitative imaging MC-1 activity in the living brain using PET. (orig.)

Brain imaging and memory systems in humans: the contribution of PET methods

International Nuclear Information System (INIS)

Perani, D.

1998-01-01

The development of neuroimaging methods such as PET, has provided a new impulse to the study of the neural basis of cognitive functions, and has extended the field of inquiry from the analysis of the consequences of brain lesions to the functional investigations of brain activity, either in patients with selective neuropsychological deficits or in normal subjects engaged in cognitive tasks. Specific patterns of hypo-metabolism in neurological patients are associated with different profiles of memory deficits.[ 18 F]FDG PET studies have confirmed the association of episodic memory with the structures of Papez's circuit and have shown correlations between short-term and semantic memory and the language areas. The identification of anatomical-functional networks involved in specific components of memory function in normal subjects is the aim of several PET activation studies. The results are in agreement with 'neural network' models of the neural basis of memory, as complex functions subserved by multiple interconnected cortical and subcortical structures. (author)

Ten years summary: FDG-PET on irradiated brain tumour

International Nuclear Information System (INIS)

Wang Shuxia; Boethius, J.

2004-01-01

Purpose: To retrospectively evaluate FDG-PET in differentiation of post-radiotherapy status: recurrence, radiation necrosis, malignant regression of low grade primary brain tumour, and to evaluate PET in terms of survival prediction. Material and methods: 117 irradiated patients (156 PET) were consecutively included. PET results were judged by a set of rigid follow-up standards. Brain metastases from lung carcinoma were further studied. Survival time was analysed with Kaplan-Meier method. Results: There were 61 true-positive, 2 false-positive, 15 false-negative, 51 true-negative PET; leaving 5 positive and 22 negative PET results indeterminate. PET positive predictive value was 96% in all and 100% in brain metastasis from lung carcinoma. PET negative predictive value was 55.6% among surgically selected cases. Survival time was significantly longer in patient's with negative PET, both brain metastasis and primary brain tumour. Conclusions: FDG-PET was a good method to pick up tumour recurrence from radiation necrosis, especially metastasis from lung carcinoma. FDG uptake could be used as a non-invasive parameter to predict patient's prognosis. (authors)

A human friendly reporting and database system for brain PET analysis

International Nuclear Information System (INIS)

Jamzad, M.; Ishii, Kenji; Toyama, Hinako; Senda, Michio

1996-01-01

We have developed a human friendly reporting and database system for clinical brain PET (Positron Emission Tomography) scans, which enables statistical data analysis on qualitative information obtained from image interpretation. Our system consists of a Brain PET Data (Input) Tool and Report Writing Tool. In the Brain PET Data Tool, findings and interpretations are input by selecting menu icons in a window panel instead of writing a free text. This method of input enables on-line data entry into and update of the database by means of pre-defined consistent words, which facilitates statistical data analysis. The Report Writing Tool generates a one page report of natural English sentences semi-automatically by using the above input information and the patient information obtained from our PET center's main database. It also has a keyword selection function from the report text so that we can save a set of keywords on the database for further analysis. By means of this system, we can store the data related to patient information and visual interpretation of the PET examination while writing clinical reports in daily work. The database files in our system can be accessed by means of commercially available databases. We have used the 4th Dimension database that runs on a Macintosh computer and analyzed 95 cases of 18 F-FDG brain PET studies. The results showed high specificity of parietal hypometabolism for Alzheimer's patients. (author)

Simultaneous maximum a posteriori longitudinal PET image reconstruction

Science.gov (United States)

Ellis, Sam; Reader, Andrew J.

2017-09-01

Positron emission tomography (PET) is frequently used to monitor functional changes that occur over extended time scales, for example in longitudinal oncology PET protocols that include routine clinical follow-up scans to assess the efficacy of a course of treatment. In these contexts PET datasets are currently reconstructed into images using single-dataset reconstruction methods. Inspired by recently proposed joint PET-MR reconstruction methods, we propose to reconstruct longitudinal datasets simultaneously by using a joint penalty term in order to exploit the high degree of similarity between longitudinal images. We achieved this by penalising voxel-wise differences between pairs of longitudinal PET images in a one-step-late maximum a posteriori (MAP) fashion, resulting in the MAP simultaneous longitudinal reconstruction (SLR) method. The proposed method reduced reconstruction errors and visually improved images relative to standard maximum likelihood expectation-maximisation (ML-EM) in simulated 2D longitudinal brain tumour scans. In reconstructions of split real 3D data with inserted simulated tumours, noise across images reconstructed with MAP-SLR was reduced to levels equivalent to doubling the number of detected counts when using ML-EM. Furthermore, quantification of tumour activities was largely preserved over a variety of longitudinal tumour changes, including changes in size and activity, with larger changes inducing larger biases relative to standard ML-EM reconstructions. Similar improvements were observed for a range of counts levels, demonstrating the robustness of the method when used with a single penalty strength. The results suggest that longitudinal regularisation is a simple but effective method of improving reconstructed PET images without using resolution degrading priors.

Semi-Supervised Tripled Dictionary Learning for Standard-dose PET Image Prediction using Low-dose PET and Multimodal MRI

Science.gov (United States)

Wang, Yan; Ma, Guangkai; An, Le; Shi, Feng; Zhang, Pei; Lalush, David S.; Wu, Xi; Pu, Yifei; Zhou, Jiliu; Shen, Dinggang

2017-01-01

Objective To obtain high-quality positron emission tomography (PET) image with low-dose tracer injection, this study attempts to predict the standard-dose PET (S-PET) image from both its low-dose PET (L-PET) counterpart and corresponding magnetic resonance imaging (MRI). Methods It was achieved by patch-based sparse representation (SR), using the training samples with a complete set of MRI, L-PET and S-PET modalities for dictionary construction. However, the number of training samples with complete modalities is often limited. In practice, many samples generally have incomplete modalities (i.e., with one or two missing modalities) that thus cannot be used in the prediction process. In light of this, we develop a semi-supervised tripled dictionary learning (SSTDL) method for S-PET image prediction, which can utilize not only the samples with complete modalities (called complete samples) but also the samples with incomplete modalities (called incomplete samples), to take advantage of the large number of available training samples and thus further improve the prediction performance. Results Validation was done on a real human brain dataset consisting of 18 subjects, and the results show that our method is superior to the SR and other baseline methods. Conclusion This work proposed a new S-PET prediction method, which can significantly improve the PET image quality with low-dose injection. Significance The proposed method is favorable in clinical application since it can decrease the potential radiation risk for patients. PMID:27187939

Subject-specific bone attenuation correction for brain PET/MR: can ZTE-MRI substitute CT scan accurately?

Science.gov (United States)

Khalifé, Maya; Fernandez, Brice; Jaubert, Olivier; Soussan, Michael; Brulon, Vincent; Buvat, Irène; Comtat, Claude

2017-10-01

In brain PET/MR applications, accurate attenuation maps are required for accurate PET image quantification. An implemented attenuation correction (AC) method for brain imaging is the single-atlas approach that estimates an AC map from an averaged CT template. As an alternative, we propose to use a zero echo time (ZTE) pulse sequence to segment bone, air and soft tissue. A linear relationship between histogram normalized ZTE intensity and measured CT density in Hounsfield units (HU ) in bone has been established thanks to a CT-MR database of 16 patients. Continuous AC maps were computed based on the segmented ZTE by setting a fixed linear attenuation coefficient (LAC) to air and soft tissue and by using the linear relationship to generate continuous μ values for the bone. Additionally, for the purpose of comparison, four other AC maps were generated: a ZTE derived AC map with a fixed LAC for the bone, an AC map based on the single-atlas approach as provided by the PET/MR manufacturer, a soft-tissue only AC map and, finally, the CT derived attenuation map used as the gold standard (CTAC). All these AC maps were used with different levels of smoothing for PET image reconstruction with and without time-of-flight (TOF). The subject-specific AC map generated by combining ZTE-based segmentation and linear scaling of the normalized ZTE signal into HU was found to be a good substitute for the measured CTAC map in brain PET/MR when used with a Gaussian smoothing kernel of 4~mm corresponding to the PET scanner intrinsic resolution. As expected TOF reduces AC error regardless of the AC method. The continuous ZTE-AC performed better than the other alternative MR derived AC methods, reducing the quantification error between the MRAC corrected PET image and the reference CTAC corrected PET image.

Use of fluorine-18-BPA PET images and image registration to enhance radiation treatment planning for boron neutron capture therapy

Science.gov (United States)

Khan, Mohammad Khurram

The Monte-Carlo based simulation environment for radiation therapy (SERA) software is used to simulate the dose administered to a patient undergoing boron neutron capture therapy (BNCT). Point sampling of tumor tissue results in an estimate of a uniform boron concentration scaling factor of 3.5. Under conventional treatment protocols, this factor is used to scale the boron component of the dose linearly and homogenously within the tumor and target volumes. The average dose to the tumor cells by such a method could be improved by better methods of quantifying the in-vivo 10B biodistribution. A better method includes radiolabeling para-Boronophenylalanine (p-BPA) with 18F and imaging the pharmaceutical using positron emission tomography (PET). This biodistribution of 18F-BPA can then be used to better predict the average dose delivered to the tumor regions. This work uses registered 18F-BPA PET images to incorporate the in-vivo boron biodistribution within current treatment planning. The registered 18F-BPA PET images are then coupled in a new computer software, PET2MRI.m, to linearly scale the boron component of the dose. A qualititative and quantitative assessment of the dose contours is presented using the two approaches. Tumor volume, tumor axial extent, and target locations are compared between using MRI or PET images to define the tumor volume. In addition, peak-to-normal brain value at tumor axial center is determined for pre and post surgery patients using 18F-BPA PET images. The differences noted between the registered GBM tumor volumes (range: 34.04--136.36%), tumor axial extent (range: 20--150%), and the beam target location (1.27--4.29 cm) are significantly different. The peak-to-normal brain values are also determined at the tumor axial center using the 18F-BPA PET images. The peak-to-normal brain values using the last frame of the pre-surgery study for the GBM patients ranged from 2.05--3.4. For post surgery time weighted PET data, the peak

Minireview of Stereoselective Brain Imaging

DEFF Research Database (Denmark)

Smith, Donald F.; Jakobsen, Steen

2014-01-01

Stereoselectivity is a fundamental principle in living systems. Stereoselectivity reflects the dependence of molecular processes on the spatial orientation of constituent atoms. Stereoselective processes govern many aspects of brain function and direct the course of many psychotropic drugs. Today......, modern imaging techniques such as SPECT and PET provide a means for studying stereoselective processes in the living brain. Chemists have prepared numerous radiolabelled stereoisomers for use in SPECT and PET in order to explore various molecular processes in the living brain of anesthetized laboratory...... animals and awake humans. The studies have demonstrated how many aspects of neurotransmission consist of crucial stereoselective events that can affect brain function in health and disease. Here, we present a brief account of those findings in hope of stimulating further interest in the vital topic....

Evaluation of potential PET imaging probes for the orexin 2 receptors

International Nuclear Information System (INIS)

Wang, Changning; Wilson, Colin M.; Moseley, Christian K.; Carlin, Stephen M.; Hsu, Shirley; Arabasz, Grae; Schroeder, Frederick A.; Sander, Christin Y.; Hooker, Jacob M.

2013-01-01

A wide range of central nervous system (CNS) disorders, particularly those related to sleep, are associated with the abnormal function of orexin (OX) receptors. Several orexin receptor antagonists have been reported in recent years, but currently there are no imaging tools to probe the density and function of orexin receptors in vivo. To date there are no published data on the pharmacokinetics (PK) and accumulation of some lead orexin receptor antagonists. Evaluation of CNS pharmacokinetics in the pursuit of positron emission tomography (PET) radiotracer development could be used to elucidate the association of orexin receptors with diseases and to facilitate the drug discovery and development. To this end, we designed and evaluated carbon-11 labeled compounds based on diazepane orexin receptor antagonists previously described. One of the synthesized compounds, [ 11 C]CW4, showed high brain uptake in rats and further evaluated in non-human primate (NHP) using PET-MR imaging. PET scans performed in a baboon showed appropriate early brain uptake for consideration as a radiotracer. However, [ 11 C]CW4 exhibited fast kinetics and high nonspecific binding, as determined after co-administration of [ 11 C]CW4 and unlabeled CW4. These properties indicate that [ 11 C]CW4 has excellent brain penetrance and could be used as a lead compound for developing new CNS-penetrant PET imaging probes of orexin receptors

MR-guided PET motion correction in LOR space using generic projection data for image reconstruction with PRESTO

International Nuclear Information System (INIS)

Scheins, J.; Ullisch, M.; Tellmann, L.; Weirich, C.; Rota Kops, E.; Herzog, H.; Shah, N.J.

2013-01-01

The BrainPET scanner from Siemens, designed as hybrid MR/PET system for simultaneous acquisition of both modalities, provides high-resolution PET images with an optimum resolution of 3 mm. However, significant head motion often compromises the achievable image quality, e.g. in neuroreceptor studies of human brain. This limitation can be omitted when tracking the head motion and accurately correcting measured Lines-of-Response (LORs). For this purpose, we present a novel method, which advantageously combines MR-guided motion tracking with the capabilities of the reconstruction software PRESTO (PET Reconstruction Software Toolkit) to convert motion-corrected LORs into highly accurate generic projection data. In this way, the high-resolution PET images achievable with PRESTO can also be obtained in presence of severe head motion

Preclinical evaluation and quantification of [(18)F]MK-9470 as a radioligand for PET imaging of the type 1 cannabinoid receptor in rat brain

OpenAIRE

Casteels, Cindy; Koole, Michel; Celen, Sofie; Bormans, Guy; Van Laere, Koen

2012-01-01

PURPOSE: [(18)F]MK-9470 is an inverse agonist for the type 1 cannabinoid (CB1) receptor allowing its use in PET imaging. We characterized the kinetics of [(18)F]MK-9470 and evaluated its ability to quantify CB1 receptor availability in the rat brain. METHODS: Dynamic small-animal PET scans with [(18)F]MK-9470 were performed in Wistar rats on a FOCUS-220 system for up to 10 h. Both plasma and perfused brain homogenates were analysed using HPLC to quantify radiometabolites. Displacement and blo...

An SPM8-based approach for attenuation correction combining segmentation and nonrigid template formation: application to simultaneous PET/MR brain imaging.

Science.gov (United States)

Izquierdo-Garcia, David; Hansen, Adam E; Förster, Stefan; Benoit, Didier; Schachoff, Sylvia; Fürst, Sebastian; Chen, Kevin T; Chonde, Daniel B; Catana, Ciprian

2014-11-01

We present an approach for head MR-based attenuation correction (AC) based on the Statistical Parametric Mapping 8 (SPM8) software, which combines segmentation- and atlas-based features to provide a robust technique to generate attenuation maps (μ maps) from MR data in integrated PET/MR scanners. Coregistered anatomic MR and CT images of 15 glioblastoma subjects were used to generate the templates. The MR images from these subjects were first segmented into 6 tissue classes (gray matter, white matter, cerebrospinal fluid, bone, soft tissue, and air), which were then nonrigidly coregistered using a diffeomorphic approach. A similar procedure was used to coregister the anatomic MR data for a new subject to the template. Finally, the CT-like images obtained by applying the inverse transformations were converted to linear attenuation coefficients to be used for AC of PET data. The method was validated on 16 new subjects with brain tumors (n = 12) or mild cognitive impairment (n = 4) who underwent CT and PET/MR scans. The μ maps and corresponding reconstructed PET images were compared with those obtained using the gold standard CT-based approach and the Dixon-based method available on the Biograph mMR scanner. Relative change (RC) images were generated in each case, and voxel- and region-of-interest-based analyses were performed. The leave-one-out cross-validation analysis of the data from the 15 atlas-generation subjects showed small errors in brain linear attenuation coefficients (RC, 1.38% ± 4.52%) compared with the gold standard. Similar results (RC, 1.86% ± 4.06%) were obtained from the analysis of the atlas-validation datasets. The voxel- and region-of-interest-based analysis of the corresponding reconstructed PET images revealed quantification errors of 3.87% ± 5.0% and 2.74% ± 2.28%, respectively. The Dixon-based method performed substantially worse (the mean RC values were 13.0% ± 10.25% and 9.38% ± 4.97%, respectively). Areas closer to the skull showed

PET pharmacokinetic analysis to estimate boron concentration in tumor and brain as a guide to plan BNCT for malignant cerebral glioma

International Nuclear Information System (INIS)

Nariai, Tadashi; Ishiwata, Kiichi; Kimura, Yuichi; Inaji, Motoki; Momose, Toshiya; Yamamoto, Tetsuya; Matsumura, Akira; Ishii, Kenji; Ohno, Kikuo

2009-01-01

Introduction: To plan the optimal BNCT for patients with malignant cerebral glioma, estimation of the ratio of boron concentration in tumor tissue against that in the surrounding normal brain (T/N ratio of boron) is important. We report a positron emission tomography (PET) imaging method to estimate T/N ratio of tissue boron concentration based on pharmacokinetic analysis of amino acid probes. Methods: Twelve patients with cerebral malignant glioma underwent 60 min dynamic PET scanning of brain after bolus injection of 18 F-borono-phenyl-alanine (FBPA) with timed arterial blood sampling. Using kinetic parameter obtained by this scan, T/N ratio of boron concentration elicited by one-hour constant infusion of BPA, as performed in BNCT, was simulated on Runge-Kutta algorithm. 11 C-methionine (MET) PET scan, which is commonly used in worldwide PET center as brain tumor imaging tool, was also performed on the same day to compare the image characteristics of FBPA and that of MET. Result: PET glioma images obtained with FBPA and MET are almost identical in all patients by visual inspection. Estimated T/N ratio of tissue boron concentration after one-hour constant infusion of BPA, T/N ratio of FBPA on static condition, and T/N ratio of MET on static condition showed significant linear correlation between each other. Conclusion: T/N ratio of boron concentration that is obtained by constant infusion of BPA during BNCT can be estimated by FBPA PET scan. This ratio can also be estimated by MET-PET imaging. As MET-PET study is available in many clinical PET center, selection of candidates for BNCT may be possible by MET-PET images. Accurate planning of BNCT may be performed by static images of FBPA PET. Use of PET imaging with amino acid probes may contribute very much to establish an appropriate application of BNCT for patients with malignant glioma.

Effect of MRI acoustic noise on cerebral fludeoxyglucose uptake in simultaneous MR-PET imaging.

Science.gov (United States)

Chonde, Daniel B; Abolmaali, Nasreddin; Arabasz, Grae; Guimaraes, Alexander R; Catana, Ciprian

2013-05-01

Integrated scanners capable of simultaneous positron emission tomography (PET) and magnetic resonance imaging (MRI) data acquisition are now available for human use. Although the scanners' manufacturers have made substantial efforts to understand and minimize the mutual electromagnetic interference between the 2 modalities, the potential physiological inference has not been evaluated. In this study, we have studied the influence of the acoustic noise produced by the magnetic resonance (MR) gradients on brain fludeoxyglucose (FDG) uptake in the Siemens MR-BrainPET prototype. Although particular attention was paid to the primary auditory cortex (PAC), a brain-wide analysis was also performed. The effects of the MR on the PET count rate and image quantification were first investigated in phantoms. Next, 10 healthy volunteers underwent 2 simultaneous FDG-PET/MR scans in the supine position with the FDG injection occurring inside the MR-BrainPET, alternating between a "quiet" (control) environment in which no MR sequences were run during the FDG uptake phase (the first 40 minutes after radiotracer administration) and a "noisy" (test) environment in which MR sequences were run for the entire time. Cortical and subcortical regions of interest were derived from the high-resolution morphological MR data using FreeSurfer. The changes in the FDG uptake in the FreeSurfer-derived regions of interest between the 2 conditions were analyzed from parametric and static PET images, and on a voxel-by-voxel basis using SPM8 and FreeSurfer. Only minimal to no electromagnetic interference was observed for most of the MR sequences tested, with a maximum drop in count rate of 1.5% and a maximum change in the measured activity of 1.1% in the corresponding images. The region of interest-based analysis showed statistically significant increases in the right PAC in both the parametric (9.13% [4.73%]) and static (4.18% [2.87%]) images. The SPM8 analysis showed no statistically significant

Trends in PET imaging

International Nuclear Information System (INIS)

Moses, William W.

2000-01-01

Positron Emission Tomography (PET) imaging is a well established method for obtaining information on the status of certain organs within the human body or in animals. This paper presents an overview of recent trends PET instrumentation. Significant effort is being expended to develop new PET detector modules, especially those capable of measuring depth of interaction. This is aided by recent advances in scintillator and pixellated photodetector technology. The other significant area of effort is development of special purpose PET cameras (such as for imaging breast cancer or small animals) or cameras that have the ability to image in more than one modality (such as PET / SPECT or PET / X-Ray CT)

An SPM8-based Approach for Attenuation Correction Combining Segmentation and Non-rigid Template Formation: Application to Simultaneous PET/MR Brain Imaging

Science.gov (United States)

Izquierdo-Garcia, David; Hansen, Adam E.; Förster, Stefan; Benoit, Didier; Schachoff, Sylvia; Fürst, Sebastian; Chen, Kevin T.; Chonde, Daniel B.; Catana, Ciprian

2014-01-01

We present an approach for head MR-based attenuation correction (MR-AC) based on the Statistical Parametric Mapping (SPM8) software that combines segmentation- and atlas-based features to provide a robust technique to generate attenuation maps (µ-maps) from MR data in integrated PET/MR scanners. Methods Coregistered anatomical MR and CT images acquired in 15 glioblastoma subjects were used to generate the templates. The MR images from these subjects were first segmented into 6 tissue classes (gray and white matter, cerebro-spinal fluid, bone and soft tissue, and air), which were then non-rigidly coregistered using a diffeomorphic approach. A similar procedure was used to coregister the anatomical MR data for a new subject to the template. Finally, the CT-like images obtained by applying the inverse transformations were converted to linear attenuation coefficients (LACs) to be used for AC of PET data. The method was validated on sixteen new subjects with brain tumors (N=12) or mild cognitive impairment (N=4) who underwent CT and PET/MR scans. The µ-maps and corresponding reconstructed PET images were compared to those obtained using the gold standard CT-based approach and the Dixon-based method available on the Siemens Biograph mMR scanner. Relative change (RC) images were generated in each case and voxel- and region of interest (ROI)-based analyses were performed. Results The leave-one-out cross-validation analysis of the data from the 15 atlas-generation subjects showed small errors in brain LACs (RC=1.38%±4.52%) compared to the gold standard. Similar results (RC=1.86±4.06%) were obtained from the analysis of the atlas-validation datasets. The voxel- and ROI-based analysis of the corresponding reconstructed PET images revealed quantification errors of 3.87±5.0% and 2.74±2.28%, respectively. The Dixon-based method performed substantially worse (the mean RC values were 13.0±10.25% and 9.38±4.97%, respectively). Areas closer to skull showed the largest

Segmentation of 3D microPET images of the rat brain via the hybrid gaussian mixture method with kernel density estimation.

Science.gov (United States)

Chen, Tai-Been; Chen, Jyh-Cheng; Lu, Henry Horng-Shing

2012-01-01

Segmentation of positron emission tomography (PET) is typically achieved using the K-Means method or other approaches. In preclinical and clinical applications, the K-Means method needs a prior estimation of parameters such as the number of clusters and appropriate initialized values. This work segments microPET images using a hybrid method combining the Gaussian mixture model (GMM) with kernel density estimation. Segmentation is crucial to registration of disordered 2-deoxy-2-fluoro-D-glucose (FDG) accumulation locations with functional diagnosis and to estimate standardized uptake values (SUVs) of region of interests (ROIs) in PET images. Therefore, simulation studies are conducted to apply spherical targets to evaluate segmentation accuracy based on Tanimoto's definition of similarity. The proposed method generates a higher degree of similarity than the K-Means method. The PET images of a rat brain are used to compare the segmented shape and area of the cerebral cortex by the K-Means method and the proposed method by volume rendering. The proposed method provides clearer and more detailed activity structures of an FDG accumulation location in the cerebral cortex than those by the K-Means method.

Effect of MRI Acoustic Noise on Cerebral FDG Uptake in Simultaneous MR-PET Imaging

Science.gov (United States)

Abolmaali, Nasreddin; Arabasz, Grae; Guimaraes, Alexander R.; Catana, Ciprian

2013-01-01

Integrated scanners capable of simultaneous PET and MRI data acquisition are now available for human use. Although the scanners’ manufacturers have made substantial efforts to understand and minimize the mutual electromagnetic interference between the two modalities, the potential physiological inference has not been evaluated. In this work, we have studied the influence of the acoustic noise produced by the MR gradients on brain FDG uptake in the Siemens MR-BrainPET prototype. While particular attention was paid to the primary auditory cortex (PAC), a brain-wide analysis was also performed. Methods The effects of the MR on the PET count rate and image quantification were first investigated in phantoms. Next, ten healthy volunteers underwent two simultaneous FDG-PET/MR scans in the supine position with the FDG injection occurring inside the MR-BrainPET, alternating between a “quiet” (control) environment in which no MR sequences were run during the FDG uptake phase (the first 40 minutes after radiotracer administration) and a “noisy” (test) case in which MR sequences were run for the entire time. Cortical and subcortical regions of interest (ROIs) were derived from the high-resolution morphological MR data using FreeSurfer. The changes in FDG uptake in the FreeSurfer-derived ROIs between the two conditions were analyzed from parametric and static PET images, and on a voxel-by-voxel basis using SPM8 and FreeSurfer. Results Only minimal to no electromagnetic interference was observed for most of the MR sequences tested, with a maximum drop in count rate of 1.5% and a maximum change in the measured activity of 1.1% in the corresponding images. The ROI-based analysis showed statistically significant increases in the right PAC in both the parametric (9.13±4.73%) and static (4.18±2.87%) images. SPM8 analysis showed no statistically significant clusters in any images when a p<0.05 (corrected) was used; however, a p<0.001 (uncorrected) resolved bilateral

PET/MR Imaging in Gynecologic Oncology.

Science.gov (United States)

Ohliger, Michael A; Hope, Thomas A; Chapman, Jocelyn S; Chen, Lee-May; Behr, Spencer C; Poder, Liina

2017-08-01

MR imaging and PET using 2-Deoxy-2-[ 18 F]fluoroglucose (FDG) are both useful in the evaluation of gynecologic malignancies. MR imaging is superior for local staging of disease whereas fludeoxyglucose FDG PET is superior for detecting distant metastases. Integrated PET/MR imaging scanners have great promise for gynecologic malignancies by combining the advantages of each modality into a single scan. This article reviews the technology behind PET/MR imaging acquisitions and technical challenges relevant to imaging the pelvis. A dedicated PET/MR imaging protocol; the roles of PET and MR imaging in cervical, endometrial, and ovarian cancers; and future directions for PET/MR imaging are discussed. Copyright © 2017 Elsevier Inc. All rights reserved.

PET-CT imaging with [18F]-gefitinib to measure Abcb1a/1b (P-gp) and Abcg2 (Bcrp1) mediated drug–drug interactions at the murine blood–brain barrier

International Nuclear Information System (INIS)

Vlaming, Maria L.H.; Läppchen, Tilman; Jansen, Harm T.; Kivits, Suzanne; Driel, Andy van; Steeg, Evita van de; Hoorn, José W. van der; Sio, Charles F.; Steinbach, Oliver C.; DeGroot, Jeroen

2015-01-01

Introduction: The efflux transporters P-glycoprotein (P-gp, ABCB1) and breast cancer resistance protein (BCRP, ABCG2) are expressed at the blood–brain barrier (BBB), and can limit the access of a wide range of drugs to the brain. In this study we developed a PET-CT imaging method for non-invasive, quantitative analysis of the effect of ABCB1 and ABCG2 on brain penetration of the anti-cancer drug gefitinib, and demonstrated the applicability of this method for identification and quantification of potential modulators of ABCB1 and ABCB2 using the dual inhibitor elacridar. Methods: In vitro cellular accumulation studies with [ 14 C]-gefitinib were conducted in LLC-PK1, MDCKII, and the corresponding ABCB1/Abcb1a and ABCG2/Abcg2 overexpressing cell lines. Subsequently, in vivo brain penetration of [ 18 F]-gefitinib was quantified by PET-CT imaging studies in wild-type, Abcg2 −/− , Abcb1a/1b −/− , and Abcb1a/1b;Abcg2 −/− mice. Results: In vitro studies showed that [ 14 C]-gefitinib is a substrate of the human ABCB1 and ABCG2 transporters. After i.v. administration of [ 18 F]-gefitinib (1 mg/kg), PET-CT imaging showed 2.3-fold increased brain levels of [ 18 F]-gefitinib in Abcb1a/1b;Abcg2 −/− mice, compared to wild-type. Levels in single knockout animals were not different from wild-type, showing that Abcb1a/1b and Abcg2 together limit access of [ 18 F]-gefitinib to the brain. Furthermore, enhanced brain accumulation of [ 18 F]-gefitinib after administration of the ABCB1 and ABCG2 inhibitor elacridar (10 mg/kg) could be quantified with PET-CT imaging. Conclusions: PET-CT imaging with [ 18 F]-gefitinib is a powerful tool to non-invasively assess potential ABCB1- and ABCG2-mediated drug–drug interactions (DDIs) in vivo. Advances in knowledge and implications for patient care: This minimally-invasive, [ 18 F]-based PET-CT imaging method shows the interplay of ABCB1 and ABCG2 at the BBB in vivo. The method may be applied in the future to assess ABCB1 and

The MINDView brain PET detector, feasibility study based on SiPM arrays

Energy Technology Data Exchange (ETDEWEB)

González, Antonio J., E-mail: agonzalez@i3m.upv.es [Institute for Instrumentation in Molecular Imaging (I3M), 46022 Valencia (Spain); Majewski, Stan [Radiology Research, Department of Radiology, University of Virginia, VA 22903 (United States); Sánchez, Filomeno [Institute for Instrumentation in Molecular Imaging (I3M), 46022 Valencia (Spain); Aussenhofer, Sebastian [NORAS MRI products GmbH, Hochberg (Germany); Aguilar, Albert; Conde, Pablo; Hernández, Liczandro; Vidal, Luis F. [Institute for Instrumentation in Molecular Imaging (I3M), 46022 Valencia (Spain); Pani, Roberto; Bettiol, Marco; Fabbri, Andrea [Department of Molecular Medicine, Sapienza University of Rome (Italy); Bert, Julien; Visvikis, Dimitris [Université de Bretagne Occidentale, Brest (France); Jackson, Carl; Murphy, John; O’Neill, Kevin [SensL Technologies, Cork (Ireland); Benlloch, Jose M. [Institute for Instrumentation in Molecular Imaging (I3M), 46022 Valencia (Spain)

2016-05-11

The Multimodal Imaging of Neurological Disorders (MINDView) project aims to develop a dedicated brain Positron Emission Tomography (PET) scanner with sufficient resolution and sensitivity to visualize neurotransmitter pathways and their disruptions in mental disorders for diagnosis and follow-up treatment. The PET system should be compact and fully compatible with a Magnetic Resonance Imaging (MRI) device in order to allow its operation as a PET brain insert in a hybrid imaging setup with most MRI scanners. The proposed design will enable the currently-installed MRI base to be easily upgraded to PET/MRI systems. The current design for the PET insert consists of a 3-ring configuration with 20 modules per ring and an axial field of view of ~15 cm and a geometrical aperture of ~33 cm in diameter. When coupled to the new head Radio Frequency (RF) coil, the inner usable diameter of the complete PET-RF coil insert is reduced to 26 cm. Two scintillator configurations have been tested, namely a 3-layer staggered array of LYSO with 1.5 mm pixel size, with 35×35 elements (6 mm thickness each) and a black-painted monolithic LYSO block also covering about 50×50 mm{sup 2} active area with 20 mm thickness. Laboratory test results associated with the current MINDView PET module concept are presented in terms of key parameters' optimization, such as spatial and energy resolution, sensitivity and Depth of Interaction (DOI) capability. It was possible to resolve all pixel elements from the three scintillator layers with energy resolutions as good as 10%. The monolithic scintillator showed average detector resolutions varying from 3.5 mm in the entrance layer to better than 1.5 mm near the photosensor, with average energy resolutions of about 17%.

Imaging with PET system

International Nuclear Information System (INIS)

Das, B.K.; Noreen Norfaraheen Lee Abdullah

2012-01-01

PET deals with biochemistry and metabolic changes that occur at molecular level. Hence, PET differs fundamentally from other imaging modalities. CT imaging is based on tissue density, whereas MRI conveys anatomic information based on proton density and proton relaxation dynamics. CT and MRI are useful in clinical diagnosis only when disease process has caused significant anatomic alterations. However, in most disease conditions chemical changes precede anatomic changes, that can be detected by PET technology. Thus, PET can provide earliest and unique information about ongoing disease process long before anatomic or structural changes take place. There is no other modality available at present that can replace PET technology. Although PET produces cross-sectional images like that obtained in MRI or CT, they represent circulation, function and metabolism, and not anatomic structure. PET is extremely sensitive measuring quantitatively concentration of tracers in nano to pico-molar range. Thus, PET enables merger of biochemistry and biology in medicine giving birth to molecular medicine that focuses on identifying the molecular errors of disease leading to developing molecular corrections including gene therapy. Molecular imaging with PET has been playing a role in examining the biological nature of a disease condition and its characterization to guide selection and evaluation of treatment. (author)

Intra-individual comparison of F-18-FLT PET and F-18 FET PET in brain tumor patients

International Nuclear Information System (INIS)

Kim, S.; Cheon, G.J.; Cho, Y.S.; Kwak, H.S.; Lee, C.H.; Choi, C.W.; Lim, S.M.

2004-01-01

Full text: The nucleoside analogue 18F-3'-deoxy-3'-fluorothymidine (FLT) for cellular proliferation and the amino acid analogue O- (2'18F-fluoroethyl)-L-tyrosine (FET) are recently developed PET-tracer for tumor imaging. Previous studies have demonstrated that the diagnostic ability of FET PET better than FDG PET in patient with newly diagnosed or recurrent brain tumors after radiation therapy. To compare findings on FLT PET with FET PET, we prospectively undertook FLT, FET and FDG PET in same patient with suspected primary/metastatic and recurrent brain tumors. Seventeen studies (FLT +FET + FDG: 13, FLT+FDG: 3, FLT +FET: 1) in 16 consecutive patients (47 ± 8.3 years, M: F 10: 6) with brain tumor (3 for initial diagnosis, 6 for therapeutic response, 6 for detecting recurrence, 1 for diagnosis and recurrence both) were included. Brain tumors were 14 gliomas (6 high-grade, 9 low-grade by the WHO classification), 2 metastatic brain tumors and 1 CNS lymphoma. 18F-FDG, FLT and FET PET were performed within two weeks. Attenuation-corrected brain images were acquired 30 minutes after injection of 370-555 MBq FDG, FLT and FET with a dedicated PET scanner (ECAT HR+ scanner, Siemens-CTI, Knoxville, Tenn., USA). Maximum SUV (max SUV) and relative uptake defined by FLT and FET accumulation within the tumor in relation to a contra lateral control region (max SUV for tumor/mean SUV for contra lateral normal gray matter) were calculated. A total of 26 tumor foci (26 on FLT and FDG, 22 on FET) in 17 studies were analysed. In most of tumor foci (20 of 22) FLT and FET PET images showed a similar extent of tumor activity. In 2 tumor foci discrepant findings were noticed; intense FLT uptake with negative FLT uptake in primary CNS lymphoma and negative FLT uptake with mild FET uptake in low-grade astrocytoma. Overall positive FLT, FET and FDG uptakes were 85 % (22/26), 90 % (18/ 20) and 58 % (15/26) respectively. Max SUV and relative FLT/FET uptake: The mean max SUV of FLT (0.97 ± 0

Fluorine-18 nuclide and its PET imaging agent

International Nuclear Information System (INIS)

Wang Mingfang

2003-01-01

Fluorine-18 has predominant physical features with long half-life and the enough time for preparation of radiopharmaceuticals and PET imaging. Also, the chemical nature of fluorine-18 is similar to that of hydrogen, and the fluorine-18 labelled organic molecules can not change the non-labelled molecular character. Therefore, fluorine-18 is widely applied in the labelled glucose, amino acids, fatty acids, nucleotide, receptor-ligand and neurotransmitter molecular etc., with the propose of detecting the blood flow, metabolism, synthesis of the protein and the neurotransmitter function in brain by PET imaging. It is very important in the basic science and clinical research to understand and master the preparation of the fluorine-18 and its labelled compounds

PET pharmacokinetic analysis to estimate boron concentration in tumor and brain as a guide to plan BNCT for malignant cerebral glioma

Energy Technology Data Exchange (ETDEWEB)

Nariai, Tadashi [Department of Neurosurgery, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo (Japan)], E-mail: nariai.nsrg@tmd.ac.jp; Ishiwata, Kiichi [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, 1-1, Nakacho, Itabashi-ku, Tokyo (Japan); Kimura, Yuichi [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba (Japan); Inaji, Motoki; Momose, Toshiya [Department of Neurosurgery, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo (Japan); Yamamoto, Tetsuya; Matsumura, Akira [Department of Neurosurgery, University of Tsukuba, Tennodai, Tsukuba, Igaraki (Japan); Ishii, Kenji [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, 1-1, Nakacho, Itabashi-ku, Tokyo (Japan); Ohno, Kikuo [Department of Neurosurgery, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo (Japan)

2009-07-15

Introduction: To plan the optimal BNCT for patients with malignant cerebral glioma, estimation of the ratio of boron concentration in tumor tissue against that in the surrounding normal brain (T/N ratio of boron) is important. We report a positron emission tomography (PET) imaging method to estimate T/N ratio of tissue boron concentration based on pharmacokinetic analysis of amino acid probes. Methods: Twelve patients with cerebral malignant glioma underwent 60 min dynamic PET scanning of brain after bolus injection of {sup 18}F-borono-phenyl-alanine (FBPA) with timed arterial blood sampling. Using kinetic parameter obtained by this scan, T/N ratio of boron concentration elicited by one-hour constant infusion of BPA, as performed in BNCT, was simulated on Runge-Kutta algorithm. {sup 11}C-methionine (MET) PET scan, which is commonly used in worldwide PET center as brain tumor imaging tool, was also performed on the same day to compare the image characteristics of FBPA and that of MET. Result: PET glioma images obtained with FBPA and MET are almost identical in all patients by visual inspection. Estimated T/N ratio of tissue boron concentration after one-hour constant infusion of BPA, T/N ratio of FBPA on static condition, and T/N ratio of MET on static condition showed significant linear correlation between each other. Conclusion: T/N ratio of boron concentration that is obtained by constant infusion of BPA during BNCT can be estimated by FBPA PET scan. This ratio can also be estimated by MET-PET imaging. As MET-PET study is available in many clinical PET center, selection of candidates for BNCT may be possible by MET-PET images. Accurate planning of BNCT may be performed by static images of FBPA PET. Use of PET imaging with amino acid probes may contribute very much to establish an appropriate application of BNCT for patients with malignant glioma.

Current status of PET imaging in Huntington's disease

International Nuclear Information System (INIS)

Pagano, Gennaro; Niccolini, Flavia; Politis, Marios

2016-01-01

To review the developments of recent decades and the current status of PET molecular imaging in Huntington's disease (HD). A systematic review of PET studies in HD was performed. The MEDLINE, Web of Science, Cochrane and Scopus databases were searched for articles in all languages published up to 19 August 2015 using the major medical subject heading ''Huntington Disease'' combined with text and key words ''Huntington Disease'', ''Neuroimaging'' and ''PET''. Only peer-reviewed, primary research studies in HD patients and premanifest HD carriers, and studies in which clinical features were described in association with PET neuroimaging results, were included in this review. Reviews, case reports and nonhuman studies were excluded. A total of 54 PET studies were identified and analysed in this review. Brain metabolism ([ 18 F]FDG and [ 15 O]H 2 O), presynaptic ([ 18 F]fluorodopa, [ 11 C]β-CIT and [ 11 C]DTBZ) and postsynaptic ([ 11 C]SCH22390, [ 11 C]FLB457 and [ 11 C]raclopride) dopaminergic function, phosphodiesterases ([ 18 F]JNJ42259152, [ 18 F]MNI-659 and [ 11 C]IMA107), and adenosine ([ 18 F]CPFPX), cannabinoid ([ 18 F]MK-9470), opioid ([ 11 C]diprenorphine) and GABA ([ 11 C]flumazenil) receptors were evaluated as potential biomarkers for monitoring disease progression and for assessing the development and efficacy of novel disease-modifying drugs in premanifest HD carriers and HD patients. PET studies evaluating brain restoration and neuroprotection were also identified and described in detail. Brain metabolism, postsynaptic dopaminergic function and phosphodiesterase 10A levels were proven to be powerful in assessing disease progression. However, no single technique may be currently considered an optimal biomarker and an integrative multimodal imaging approach combining different techniques should be developed for monitoring potential neuroprotective and preventive treatment

PET image reconstruction using multi-parametric anato-functional priors

Science.gov (United States)

Mehranian, Abolfazl; Belzunce, Martin A.; Niccolini, Flavia; Politis, Marios; Prieto, Claudia; Turkheimer, Federico; Hammers, Alexander; Reader, Andrew J.

2017-08-01

In this study, we investigate the application of multi-parametric anato-functional (MR-PET) priors for the maximum a posteriori (MAP) reconstruction of brain PET data in order to address the limitations of the conventional anatomical priors in the presence of PET-MR mismatches. In addition to partial volume correction benefits, the suitability of these priors for reconstruction of low-count PET data is also introduced and demonstrated, comparing to standard maximum-likelihood (ML) reconstruction of high-count data. The conventional local Tikhonov and total variation (TV) priors and current state-of-the-art anatomical priors including the Kaipio, non-local Tikhonov prior with Bowsher and Gaussian similarity kernels are investigated and presented in a unified framework. The Gaussian kernels are calculated using both voxel- and patch-based feature vectors. To cope with PET and MR mismatches, the Bowsher and Gaussian priors are extended to multi-parametric priors. In addition, we propose a modified joint Burg entropy prior that by definition exploits all parametric information in the MAP reconstruction of PET data. The performance of the priors was extensively evaluated using 3D simulations and two clinical brain datasets of [18F]florbetaben and [18F]FDG radiotracers. For simulations, several anato-functional mismatches were intentionally introduced between the PET and MR images, and furthermore, for the FDG clinical dataset, two PET-unique active tumours were embedded in the PET data. Our simulation results showed that the joint Burg entropy prior far outperformed the conventional anatomical priors in terms of preserving PET unique lesions, while still reconstructing functional boundaries with corresponding MR boundaries. In addition, the multi-parametric extension of the Gaussian and Bowsher priors led to enhanced preservation of edge and PET unique features and also an improved bias-variance performance. In agreement with the simulation results, the clinical results

PET imaging of adenosine A2A receptors

NARCIS (Netherlands)

Zhou, Xiaoyun

2017-01-01

This thesis describes the development and evaluation of [11C]preladenant as a novel radioligand for in vivo imaging of adenosine A2A receptors in the brain with positron-emission tomography (PET). The 11C-labeled drug [11C]preladenant was produced with high radiochemical yield and specific activity.

Evaluation of D-isomers of 4-borono-2-18F-fluoro-phenylalanine and O-11C-methyl-tyrosine as brain tumor imaging agents: a comparative PET study with their L-isomers in rat brain glioma.

Science.gov (United States)

Kanazawa, Masakatsu; Nishiyama, Shingo; Hashimoto, Fumio; Kakiuchi, Takeharu; Tsukada, Hideo

2018-06-13

The potential of the D-isomerization of 4-borono-2- 18 F-fluoro-phenylalanine ( 18 F-FBPA) to improve its target tumor to non-target normal brain tissue ratio (TBR) was evaluated in rat brain glioma and compared with those of L- and D- 11 C-methyl-tyrosine ( 11 C-CMT). The L- or D-isomer of 18 F-FBPA was injected into rats through the tail vein, and their whole body kinetics and distributions were assessed using the tissue dissection method up to 90 min after the injection. The kinetics of L- and D- 18 F-FBPA or L- and D- 11 C-CMT in the C-6 glioma-inoculated rat brain were measured for 90 or 60 min, respectively, using high-resolution animal PET, and their TBRs were assessed. Tissue dissection analyses showed that D- 18 F-FBPA uptake was significantly lower than that of L- 18 F-FBPA in the brain and abdominal organs, except for the kidney and bladder, reflecting the faster elimination rate of D- 18 F-FBPA than L- 18 F-FBPA from the blood to the urinary tract. PET imaging using 18 F-FBPA revealed that although the brain uptake of D- 18 F-FBPA was significantly lower than that of L- 18 F-FBPA, the TBR of the D-isomer improved to 6.93 from 1.45 for the L-isomer. Similar results were obtained with PET imaging using 11 C-CMT with a smaller improvement in TBR to 1.75 for D- 11 C-CMT from 1.33 for L- 11 C-CMT. The present results indicate that D- 18 F-FBPA is a better brain tumor imaging agent with higher TBR than its original L-isomer and previously reported tyrosine-based PET imaging agents. This improved TBR of D- 18 F-FBPA without any pre-treatments, such as tentative blood-brain barrier disruption using hyperosmotic agents or sonication, suggests that the D-isomerization of BPA results in the more selective accumulation of 10 B in tumor cells that is more effective and less toxic than conventional L-BPA.

Impact of PET/CT system, reconstruction protocol, data analysis method, and repositioning on PET/CT precision: An experimental evaluation using an oncology and brain phantom.

Science.gov (United States)

Mansor, Syahir; Pfaehler, Elisabeth; Heijtel, Dennis; Lodge, Martin A; Boellaard, Ronald; Yaqub, Maqsood

2017-12-01

In longitudinal oncological and brain PET/CT studies, it is important to understand the repeatability of quantitative PET metrics in order to assess change in tracer uptake. The present studies were performed in order to assess precision as function of PET/CT system, reconstruction protocol, analysis method, scan duration (or image noise), and repositioning in the field of view. Multiple (repeated) scans have been performed using a NEMA image quality (IQ) phantom and a 3D Hoffman brain phantom filled with 18 F solutions on two systems. Studies were performed with and without randomly (PET/CT, especially in the case of smaller spheres (PET metrics depends on the combination of reconstruction protocol, data analysis methods and scan duration (scan statistics). Moreover, precision was also affected by phantom repositioning but its impact depended on the data analysis method in combination with the reconstructed voxel size (tissue fraction effect). This study suggests that for oncological PET studies the use of SUV peak may be preferred over SUV max because SUV peak is less sensitive to patient repositioning/tumor sampling. © 2017 The Authors. Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

FDG-PET/CT brain findings in a patient with macrophagic myofascilitis

Energy Technology Data Exchange (ETDEWEB)

Der Gucht, Axel Van; Itti, Emmanuel; Aoun-Sebaliti, Mehdi; Kauv, Paul; Aouizerate, Jessie; Gherardi, Romain K.; Bachoud-Levi, Anne-Catherine; Authier, Francois-Jerome [Paris/Paris-Est University, Paris (France); Verger, Antoine [CHU Nancy, Nuclear Medecine and Nancyclotep Experimental Imaging Platform, Nancy (France); Guedj, Eric [Assistance Publique des Hircumflex, Marseille (France)

2016-03-15

Brain Positron Emission Tomography/Computed Tomography with {sup 18}F-fluorodeoxyglucose (FDG PET/CT) was performed in a 44-year-old woman with marked cognitive impairment, diffuse myalgias, sensory, memory and visual disorders, and chronic fatigue, presenting with histopathological features of macrophagic myofasciitis (MMF) at deltoid muscle biopsy. Cerebromedullary Magnetic Resonance Imaging (MRI), electromyography, ophthalmic examination, and cerebrospinal fluid analysis were normal. Visual analysis of FDG PET/CT images showed an atypical pattern of hypometabolism, involving symmetrically the occipital cortex, temporal lobes, and limbic system (including in particular amygdalo-hippocampal complexes), and the cerebellum. Posterior cingulate cortex and parietal areas were preserved. This pattern was confirmed by a voxel-based procedure using Statistical Parametric Mapping (SPM12) that compared a patient's images to normal reference samples from six healthy subjects with adjustment to age obtained using the same PET/CT camera. These results provide a glucose metabolism substrate for cognitive complaints in patients with long-lasting aluminium hydroxide-induced MMF.

FDG-PET/CT brain findings in a patient with macrophagic myofascilitis

International Nuclear Information System (INIS)

Der Gucht, Axel Van; Itti, Emmanuel; Aoun-Sebaliti, Mehdi; Kauv, Paul; Aouizerate, Jessie; Gherardi, Romain K.; Bachoud-Levi, Anne-Catherine; Authier, Francois-Jerome; Verger, Antoine; Guedj, Eric

2016-01-01

Brain Positron Emission Tomography/Computed Tomography with 18 F-fluorodeoxyglucose (FDG PET/CT) was performed in a 44-year-old woman with marked cognitive impairment, diffuse myalgias, sensory, memory and visual disorders, and chronic fatigue, presenting with histopathological features of macrophagic myofasciitis (MMF) at deltoid muscle biopsy. Cerebromedullary Magnetic Resonance Imaging (MRI), electromyography, ophthalmic examination, and cerebrospinal fluid analysis were normal. Visual analysis of FDG PET/CT images showed an atypical pattern of hypometabolism, involving symmetrically the occipital cortex, temporal lobes, and limbic system (including in particular amygdalo-hippocampal complexes), and the cerebellum. Posterior cingulate cortex and parietal areas were preserved. This pattern was confirmed by a voxel-based procedure using Statistical Parametric Mapping (SPM12) that compared a patient's images to normal reference samples from six healthy subjects with adjustment to age obtained using the same PET/CT camera. These results provide a glucose metabolism substrate for cognitive complaints in patients with long-lasting aluminium hydroxide-induced MMF

An investigation of head movement with a view to minimising motion artefact during SPECT and PET imaging of the brain

International Nuclear Information System (INIS)

Patterson, H.; Clarke, G.H.; Guy, R.; McKay, W.J.

1998-01-01

Full text: Motion artefact has long been recognised as a major cause of image degradation. Single Photon Emission Computerised Tomography (SPECT) and Positron Emission Tomography (PET) of the brain are playing an important role in the diagnosis and management of several neurological disorders. If these imaging modalities are to contribute fully to medical imaging it is essential that the improved spatial resolution of these systems is not compromised by patient movement. Thirty volunteer subjects have been examined using a simple video technique and the video images were used to classify and measure head movements which may occur during brain imaging. All subjects demonstrated angular movement within the transverse plane or rotation of the head. Angular movement within the sagittal plane or flexion/extension of the neck occurred in 69% of subjects and 72% of subjects exhibited translational movement of the sagittal plane. There was no movement of the coronal plane; nor was there any translational movement of the sagittal plane. These results suggest that when positioning the patient's head for brain imaging a system of head restraint which minimises rotation of the head should be used if image quality is to be maintained

The methods of PET cerebral imaging in focus localizing of epilepsy

International Nuclear Information System (INIS)

Bai Xia; Wang Xuemei

2009-01-01

Epilepsy is a very complicate and synthetic disease which influence patients intelligence and daily life acutely. But the cure rate of epilepsy is much low. One of the results is precise localization of disease which result in epilepsy. Today the main methods are electroencephalogram, magnetic resonance imaging, magnetic resonance spectroscopy and PET cerebral imaging. PET cerebral imaging can locate epileptic foci of epilepsy from the brain organization metabolism, blood, the bio-chemical, function and oxygen consume, the chemistry pass quality and nerve receptor. It raises the rate of checking the epileptic foci and indicates a direction for the next treatments of epilepsy. (authors)

Brain 18F-FDG PET Metabolic Abnormalities in Patients with Long-Lasting Macrophagic Myofascitis.

Science.gov (United States)

Van Der Gucht, Axel; Aoun Sebaiti, Mehdi; Guedj, Eric; Aouizerate, Jessie; Yara, Sabrina; Gherardi, Romain K; Evangelista, Eva; Chalaye, Julia; Cottereau, Anne-Ségolène; Verger, Antoine; Bachoud-Levi, Anne-Catherine; Abulizi, Mukedaisi; Itti, Emmanuel; Authier, François-Jérôme

2017-03-01

The aim of this study was to characterize brain metabolic abnormalities in patients with macrophagic myofascitis (MMF) and the relationship with cognitive dysfunction through the use of PET with 18 F-FDG. Methods: 18 F-FDG PET brain imaging and a comprehensive battery of neuropsychological tests were performed in 100 consecutive MMF patients (age [mean ± SD], 45.9 ± 12 y; 74% women). Images were analyzed with statistical parametric mapping (SPM12). Through the use of analysis of covariance, all 18 F-FDG PET brain images of MMF patients were compared with those of a reference population of 44 healthy subjects similar in age (45.4 ± 16 y; P = 0.87) and sex (73% women; P = 0.88). The neuropsychological assessment identified 4 categories of patients: those with no significant cognitive impairment ( n = 42), those with frontal subcortical (FSC) dysfunction ( n = 29), those with Papez circuit dysfunction ( n = 22), and those with callosal disconnection ( n = 7). Results: In comparison with healthy subjects, the whole population of patients with MMF exhibited a spatial pattern of cerebral glucose hypometabolism ( P glucose hypometabolism that was most marked in MMF patients with FSC dysfunction. Further studies are needed to determine whether this pattern could represent a diagnostic biomarker of MMF in patients with chronic fatigue syndrome and cognitive dysfunction. © 2017 by the Society of Nuclear Medicine and Molecular Imaging.

Resolution improvement of brain PET images using prior information from MRI: clinical application on refractory epilepsy

International Nuclear Information System (INIS)

Silva-Rodríguez, Jesus; Tsoumpas, Charalampos; Aguiar, Pablo; Cortes, Julia; Urdaneta, Jesus Lopez

2015-01-01

An important counterpart of clinical Positron Emission Tomography (PET) for early diagnosis of neurological diseases is its low resolution. This is particularly important when evaluating diseases related to small hypometabolisms such as epilepsy. The last years, new hybrid systems combining PET with Magnetic Resonance (MR) has been increasingly used for several different clinical applications. One of the advantages of MR is the production of high spatial resolution images and a potential application of PET-MR imaging is the improvement of PET resolution using MR information. A potential advantage of resolution recovery of PET images is the enhancement of contrast delivering at the same time better detectability of small lesions or hypometabolic areas and more accurate quantification over these areas. Recently, Shidahara et al (2009) proposed a new method using wavelet transforms in order to produce PET images with higher resolution. We optimised Shidahara’s method (SFS-RR) to take into account possible shortcomings on the particular clinical datasets, and applied it to a group of patients diagnosed with refractory epilepsy. FDG-PET and MRI images were acquired sequentially and then co-registered using software tools. A complete evaluation of the PET/MR images was performed before and after the correction, including different parameters related with PET quantification, such as atlas-based metabolism asymmetry coefficients and Statistical Parametric Mapping results comparing to a database of 87 healthy subjects. Furthermore, an experienced physician analyzed the results of non-corrected and corrected images in order to evaluate improvements of detectability on a visual inspection. Clinical outcome was used as a gold standard. SFS-RR demonstrated to have a positive impact on clinical diagnosis of small hypometabolisms. New lesions were detected providing additional clinically relevant information on the visual inspection. SPM sensitivity for the detection of small

Resolution improvement of brain PET images using prior information from MRI: clinical application on refractory epilepsy

Energy Technology Data Exchange (ETDEWEB)

Silva-Rodríguez, Jesus [Instituto de Investigaciones Sanitarias (IDIS), Santiago de Compostela (Spain); Tsoumpas, Charalampos [University of Leeds, Leeds (United Kingdom); Aguiar, Pablo; Cortes, Julia [Nuclear Medicine Department, University Hospital (CHUS), Santiago de Compostela (Spain); Urdaneta, Jesus Lopez [Instituto de Investigaciones Sanitarias (IDIS), Santiago de Compostela (Spain)

2015-05-18

An important counterpart of clinical Positron Emission Tomography (PET) for early diagnosis of neurological diseases is its low resolution. This is particularly important when evaluating diseases related to small hypometabolisms such as epilepsy. The last years, new hybrid systems combining PET with Magnetic Resonance (MR) has been increasingly used for several different clinical applications. One of the advantages of MR is the production of high spatial resolution images and a potential application of PET-MR imaging is the improvement of PET resolution using MR information. A potential advantage of resolution recovery of PET images is the enhancement of contrast delivering at the same time better detectability of small lesions or hypometabolic areas and more accurate quantification over these areas. Recently, Shidahara et al (2009) proposed a new method using wavelet transforms in order to produce PET images with higher resolution. We optimised Shidahara’s method (SFS-RR) to take into account possible shortcomings on the particular clinical datasets, and applied it to a group of patients diagnosed with refractory epilepsy. FDG-PET and MRI images were acquired sequentially and then co-registered using software tools. A complete evaluation of the PET/MR images was performed before and after the correction, including different parameters related with PET quantification, such as atlas-based metabolism asymmetry coefficients and Statistical Parametric Mapping results comparing to a database of 87 healthy subjects. Furthermore, an experienced physician analyzed the results of non-corrected and corrected images in order to evaluate improvements of detectability on a visual inspection. Clinical outcome was used as a gold standard. SFS-RR demonstrated to have a positive impact on clinical diagnosis of small hypometabolisms. New lesions were detected providing additional clinically relevant information on the visual inspection. SPM sensitivity for the detection of small

Direct Parametric Reconstruction With Joint Motion Estimation/Correction for Dynamic Brain PET Data.

Science.gov (United States)

Jiao, Jieqing; Bousse, Alexandre; Thielemans, Kris; Burgos, Ninon; Weston, Philip S J; Schott, Jonathan M; Atkinson, David; Arridge, Simon R; Hutton, Brian F; Markiewicz, Pawel; Ourselin, Sebastien

2017-01-01

Direct reconstruction of parametric images from raw photon counts has been shown to improve the quantitative analysis of dynamic positron emission tomography (PET) data. However it suffers from subject motion which is inevitable during the typical acquisition time of 1-2 hours. In this work we propose a framework to jointly estimate subject head motion and reconstruct the motion-corrected parametric images directly from raw PET data, so that the effects of distorted tissue-to-voxel mapping due to subject motion can be reduced in reconstructing the parametric images with motion-compensated attenuation correction and spatially aligned temporal PET data. The proposed approach is formulated within the maximum likelihood framework, and efficient solutions are derived for estimating subject motion and kinetic parameters from raw PET photon count data. Results from evaluations on simulated [ 11 C]raclopride data using the Zubal brain phantom and real clinical [ 18 F]florbetapir data of a patient with Alzheimer's disease show that the proposed joint direct parametric reconstruction motion correction approach can improve the accuracy of quantifying dynamic PET data with large subject motion.

Comparison of the performance of {sup 18}F-FP-CIT brain PET/MR and simultaneous PET/CT: A preliminary study

Energy Technology Data Exchange (ETDEWEB)

Kwon, Sang Don; Chun, Kyung Ah [Dept. of Nuclear Medicine, Yeungnam University Hospital, Daegu (Korea, Republic of)

2016-09-15

{sup 18}F-FP-CIT [{sup 1'}8F-fluorinated N-3-fluoropropyl-2-beta-carboxymethoxy-3-beta-(4-iodophenyl) nortropane] has been well established and used for the differential diagnosis of atypical parkinsonian disorders. Recently, combined positron emission tomography (PET)/magnetic resonance (MR) was proposed as a viable alternative to PET/computed tomography (CT). The aim of this study was to compare the performances of conventional {sup 18}F-FP-CIT brain PET/CT and simultaneous PET/MR by visual inspection and quantitative analysis. Fifteen consecutive patients clinically suspected of having Parkinson's disease were recruited for the study.{sup 18}F-FP-CIT PET was performed during PET/CT and PET/MR. PET/CT image acquisition was started 90 min after intravenous injection of {sup 18}F-FP-CIT and then PET/MR images were acquired. Dopamine transporter (DAT) density in bilateral striatal subregions was assessed visually. Quantitative analyses were performed on bilateral striatal volumes of interest (VOIs) using average standardized uptake values (SUVmeans). Intraclass correlation coefficients (ICCs) and their 95 % confidence intervals (CIs) were assessed to compare PET/CT and PET/MR data. Bland-Altman plots were drawn to perform method-comparisons. All subjects showed a preferential decrease in DAT binding in the posterior putamen (PP), with relative sparing of the ventral putamen (VP). Bilateral striatal subregional binding ratio (BR) determined PET/CT and PET/MR demonstrated close interequipment correspondence (BRright caudate - ICC, 0.944; 95 % CI, 0.835-0.981, BRleft caudate - ICC, 0.917; 95 % CI, 0.753-0.972, BRright putamen - ICC, 0.976; 95 % CI, 0.929-0.992 and BRleft putamen - ICC, 0.970; 95 % CI, 0.911-0.990, respectively), and Bland-Altman plots showed interequipment agreement between the two modalities. It is known that MR provides more information about anatomical changes associated with brain diseases and to enable the anatomical allocations of

Brain imaging of serotonin 4 receptors in humans with [11C]SB207145-PET

DEFF Research Database (Denmark)

Marner, Lisbeth; Gillings, Nic; Madsen, Karine

2010-01-01

Pharmacological stimulation of the serotonin 4 (5-HT(4)) receptor has shown promise for treatment of Alzheimer's disease and major depression. A new selective radioligand, [(11)C]SB207145, for positron emission tomography (PET) was used to quantify brain 5-HT(4) receptors in sixteen healthy......(max) was in accordance with post-mortem brain studies (Spearman's r=0.83, p=0.04), and the regional binding potentials, BP(ND), were on average 2.6 in striatum, 0.42 in prefrontal cortex, and 0.91 in hippocampus. We found no effect of sex but a decreased binding with age (p=0.046). A power analysis showed that, given......-HT(4) receptor binding in human brain can be reliably assessed with [(11)C]SB207145, which is encouraging for future PET studies of drug occupancy or patients with neuropsychiatric disorders....

Magnetic Resonance-based Motion Correction for Quantitative PET in Simultaneous PET-MR Imaging.

Science.gov (United States)

Rakvongthai, Yothin; El Fakhri, Georges

2017-07-01

Motion degrades image quality and quantitation of PET images, and is an obstacle to quantitative PET imaging. Simultaneous PET-MR offers a tool that can be used for correcting the motion in PET images by using anatomic information from MR imaging acquired concurrently. Motion correction can be performed by transforming a set of reconstructed PET images into the same frame or by incorporating the transformation into the system model and reconstructing the motion-corrected image. Several phantom and patient studies have validated that MR-based motion correction strategies have great promise for quantitative PET imaging in simultaneous PET-MR. Copyright © 2017 Elsevier Inc. All rights reserved.

Increased brain temserotoneric transporter availability in adult migraineurs: ([18F]FP-CIT PET imaging pilot study

International Nuclear Information System (INIS)

Park, Eun Kyung; Hwang, Yu Mi; Chu, Min Kyung; Jung, Ki Young

2016-01-01

Recent studies have proposed central serotonergic dysfunction as a major pathophysiology of migraine. We investigated serotonin transporter (SERT) availability in migraineurs using F-18-N-(3-fluoropropyl)-2β-carbomethoxy-3β-(4-iodophenyl) nortropane ([18F]FP-CIT) positron emission tomography (PET). Brain [18F]FP-CIT PET images were obtained in eight women with migraine during headache free phase and 12 healthy adult women, 120 min after injection of 185 MBq. Non-displaceable binding potential (BP ND) of [18F]FP-CIT, which is an estimate of SERT availability, was calculated at the brainstem and compared with clinical parameters. BP ND at the brainstem was significantly higher in adult migraineurs (n = 6, 1.15 ± 0.17) than healthy subjects (0.95 ± 0.14) (p = 0.04). Healthy subjects demonstrated negative correlation between brainstem BP ND and age (r = −0.64, p = 0.02), whereas this age-related decline pattern was not found in the migraineurs. Severity of migraine attack was significantly correlated with brainstem BP ND (r = 0.66, p = 0.02), when age and duration of illness were corrected. Increased SERT availability in the brainstem of adult migraineurs indicates low serotonin neurotransmission during headache-free phase. Patients who experience more painful headaches have lower serotonin neurotransmission. [18F]FP-CIT PET is a useful in vivo imaging technique for evaluating brainstem SERT availability in migraineurs

Increased brain temserotoneric transporter availability in adult migraineurs: ([18F]FP-CIT PET imaging pilot study

Energy Technology Data Exchange (ETDEWEB)

Park, Eun Kyung [Dept. of Nuclear Medicine, Korea University Anam Hospital, Korea University College of Medicine, Seoul (Korea, Republic of); Hwang, Yu Mi [Center for Research Information, Korea University, Seoul (Korea, Republic of); Chu, Min Kyung [Dept. of Neurology, Sacred Heart Hospital, Hallym University College of Medicine, Anyang (Korea, Republic of); Jung, Ki Young [Dept. of Neurology, Seoul National University College of Medicine, Seoul (Korea, Republic of)

2016-03-15

Recent studies have proposed central serotonergic dysfunction as a major pathophysiology of migraine. We investigated serotonin transporter (SERT) availability in migraineurs using F-18-N-(3-fluoropropyl)-2β-carbomethoxy-3β-(4-iodophenyl) nortropane ([18F]FP-CIT) positron emission tomography (PET). Brain [18F]FP-CIT PET images were obtained in eight women with migraine during headache free phase and 12 healthy adult women, 120 min after injection of 185 MBq. Non-displaceable binding potential (BP ND) of [18F]FP-CIT, which is an estimate of SERT availability, was calculated at the brainstem and compared with clinical parameters. BP ND at the brainstem was significantly higher in adult migraineurs (n = 6, 1.15 ± 0.17) than healthy subjects (0.95 ± 0.14) (p = 0.04). Healthy subjects demonstrated negative correlation between brainstem BP ND and age (r = −0.64, p = 0.02), whereas this age-related decline pattern was not found in the migraineurs. Severity of migraine attack was significantly correlated with brainstem BP ND (r = 0.66, p = 0.02), when age and duration of illness were corrected. Increased SERT availability in the brainstem of adult migraineurs indicates low serotonin neurotransmission during headache-free phase. Patients who experience more painful headaches have lower serotonin neurotransmission. [18F]FP-CIT PET is a useful in vivo imaging technique for evaluating brainstem SERT availability in migraineurs.

Evaluation of MRI and cannabinoid type 1 receptor PET templates constructed using DARTEL for spatial normalization of rat brains

International Nuclear Information System (INIS)

Kronfeld, Andrea; Müller-Forell, Wibke; Buchholz, Hans-Georg; Maus, Stephan; Reuss, Stefan; Schreckenberger, Mathias; Miederer, Isabelle; Lutz, Beat

2015-01-01

Purpose: Image registration is one prerequisite for the analysis of brain regions in magnetic-resonance-imaging (MRI) or positron-emission-tomography (PET) studies. Diffeomorphic anatomical registration through exponentiated Lie algebra (DARTEL) is a nonlinear, diffeomorphic algorithm for image registration and construction of image templates. The goal of this small animal study was (1) the evaluation of a MRI and calculation of several cannabinoid type 1 (CB1) receptor PET templates constructed using DARTEL and (2) the analysis of the image registration accuracy of MR and PET images to their DARTEL templates with reference to analytical and iterative PET reconstruction algorithms. Methods: Five male Sprague Dawley rats were investigated for template construction using MRI and [ 18 F]MK-9470 PET for CB1 receptor representation. PET images were reconstructed using the algorithms filtered back-projection, ordered subset expectation maximization in 2D, and maximum a posteriori in 3D. Landmarks were defined on each MR image, and templates were constructed under different settings, i.e., based on different tissue class images [gray matter (GM), white matter (WM), and GM + WM] and regularization forms (“linear elastic energy,” “membrane energy,” and “bending energy”). Registration accuracy for MRI and PET templates was evaluated by means of the distance between landmark coordinates. Results: The best MRI template was constructed based on gray and white matter images and the regularization form linear elastic energy. In this case, most distances between landmark coordinates were <1 mm. Accordingly, MRI-based spatial normalization was most accurate, but results of the PET-based spatial normalization were quite comparable. Conclusions: Image registration using DARTEL provides a standardized and automatic framework for small animal brain data analysis. The authors were able to show that this method works with high reliability and validity. Using DARTEL templates

Evaluation of MRI and cannabinoid type 1 receptor PET templates constructed using DARTEL for spatial normalization of rat brains

Energy Technology Data Exchange (ETDEWEB)

Kronfeld, Andrea; Müller-Forell, Wibke [Institute of Neuroradiology, University Medical Center of the Johannes Gutenberg University Mainz, Langenbeckstraße 1, Mainz 55131 (Germany); Buchholz, Hans-Georg; Maus, Stephan; Reuss, Stefan; Schreckenberger, Mathias; Miederer, Isabelle, E-mail: isabelle.miederer@unimedizin-mainz.de [Department of Nuclear Medicine, University Medical Center of the Johannes Gutenberg University Mainz, Langenbeckstraße 1, Mainz 55131 (Germany); Lutz, Beat [Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, Mainz 55128 (Germany)

2015-12-15

Purpose: Image registration is one prerequisite for the analysis of brain regions in magnetic-resonance-imaging (MRI) or positron-emission-tomography (PET) studies. Diffeomorphic anatomical registration through exponentiated Lie algebra (DARTEL) is a nonlinear, diffeomorphic algorithm for image registration and construction of image templates. The goal of this small animal study was (1) the evaluation of a MRI and calculation of several cannabinoid type 1 (CB1) receptor PET templates constructed using DARTEL and (2) the analysis of the image registration accuracy of MR and PET images to their DARTEL templates with reference to analytical and iterative PET reconstruction algorithms. Methods: Five male Sprague Dawley rats were investigated for template construction using MRI and [{sup 18}F]MK-9470 PET for CB1 receptor representation. PET images were reconstructed using the algorithms filtered back-projection, ordered subset expectation maximization in 2D, and maximum a posteriori in 3D. Landmarks were defined on each MR image, and templates were constructed under different settings, i.e., based on different tissue class images [gray matter (GM), white matter (WM), and GM + WM] and regularization forms (“linear elastic energy,” “membrane energy,” and “bending energy”). Registration accuracy for MRI and PET templates was evaluated by means of the distance between landmark coordinates. Results: The best MRI template was constructed based on gray and white matter images and the regularization form linear elastic energy. In this case, most distances between landmark coordinates were <1 mm. Accordingly, MRI-based spatial normalization was most accurate, but results of the PET-based spatial normalization were quite comparable. Conclusions: Image registration using DARTEL provides a standardized and automatic framework for small animal brain data analysis. The authors were able to show that this method works with high reliability and validity. Using DARTEL

Positron Emission Tomography (PET) and its application in clinical diagnosis and functional brain organization studies

International Nuclear Information System (INIS)

Grabowska, A.; Krolicki, L.

1997-01-01

Recent advances in positron emission tomography (PET) and other brain-imaging techniques have made it possible to visualize the working brain while the human subject is thinking, speaking or planning an action. PET provides researches with an opportunity to infer the neuroanatomy of a given function. Subjects either inhale or are injected with a radioactive material that binds to a physiologically active compound in the body. This serves as a tracer of blood flow and metabolic processes that reflect the activation of a given structure by emitting gamma rays which may be detected through a tomograph. PET research has produced findings that extend our knowledge on several important issues such as cerebral representation of language, perception, attention or memory. It has also proven to be an important source of information for clinical diagnosis of various neurological and psychiatric diseases. The present article provides a short review of main achievements in those fields. However, functional brain imaging is not exempt from methodological and theoretical difficulties. The main limitations of the method have been outlined. (author)

Early [18F]florbetaben and [11C]PiB PET images are a surrogate biomarker of neuronal injury in Alzheimer's disease

International Nuclear Information System (INIS)

Tiepolt, Solveig; Patt, Marianne; Luthardt, Julia; Barthel, Henryk; Hesse, Swen; Sabri, Osama; Schroeter, Matthias L.; Hoffmann, Karl-Titus; Weise, David; Gertz, Hermann-Josef

2016-01-01

[ 18 F]FDG is a commonly used neuronal injury biomarker for early and differential diagnosis of dementia. Typically, the blood supply to the brain is closely coupled to glucose consumption. Early uptake of the Aβ tracer [ 11 C]PiB on PET images is mainly determined by cerebral blood flow and shows a high correlation with [ 18 F]FDG uptake. Uptake data for 18 F-labelled Aβ PET tracers are, however, scarce. We investigated the value of early PET images using the novel Aβ tracer [ 18 F]FBB in the diagnosis of Alzhimers disease (AD). This retrospective analysis included 22 patients with MCI or dementia who underwent dual time-point PET imaging with either [ 11 C]PiB (11 patients) or [ 18 F]FBB (11 patients) in routine clinical practice. Images were acquired 1 - 9 min after administration of both tracers and 40 - 70 min and 90 - 110 min after administration of [ 11 C]PiB and [ 18 F]FBB, respectively. The patients also underwent [ 18 F]FDG brain PET imaging. PET data were analysed visually and semiquantitatively. Associations between early Aβ tracer uptake and dementia as well as brain atrophy were investigated. Regional visual scores of early Aβ tracer and [ 18 F]FDG PET images were significantly correlated (Spearman's ρ = 0.780, P < 0.001). Global brain visual analysis revealed identical results between early Aβ tracer and [ 18 F]FDG PET images. In a VOI-based analysis, the early Aβ tracer data correlated significantly with the [ 18 F]FDG data (r = 0.779, P < 0.001), but there were no differences between [ 18 F]FBB and [ 11 C]PiB. Cortical SUVRs in regions typically affected in AD on early Aβ tracer and [ 18 F]FDG PET images were correlated with MMSE scores (ρ = 0.458, P = 0.032, and ρ = 0.456, P = 0.033, respectively). A voxel-wise group-based search for areas with relatively higher tracer uptake on early Aβ tracer PET images compared with [ 18 F]FDG PET images revealed a small cluster in the midbrain/pons; no significant clusters were found for the

Free-running ADC- and FPGA-based signal processing method for brain PET using GAPD arrays

Energy Technology Data Exchange (ETDEWEB)

Hu, Wei [Department of Electronic Engineering, Sogang University, 1 Shinsu-Dong, Mapo-Gu, Seoul 121-742 (Korea, Republic of); Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-Dong, Gangnam-Gu, Seoul 135-710 (Korea, Republic of); Choi, Yong, E-mail: ychoi.image@gmail.com [Department of Electronic Engineering, Sogang University, 1 Shinsu-Dong, Mapo-Gu, Seoul 121-742 (Korea, Republic of); Hong, Key Jo [Department of Electronic Engineering, Sogang University, 1 Shinsu-Dong, Mapo-Gu, Seoul 121-742 (Korea, Republic of); Kang, Jihoon [Department of Electronic Engineering, Sogang University, 1 Shinsu-Dong, Mapo-Gu, Seoul 121-742 (Korea, Republic of); Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-Dong, Gangnam-Gu, Seoul 135-710 (Korea, Republic of); Jung, Jin Ho [Department of Electronic Engineering, Sogang University, 1 Shinsu-Dong, Mapo-Gu, Seoul 121-742 (Korea, Republic of); Huh, Youn Suk [Department of Electronic Engineering, Sogang University, 1 Shinsu-Dong, Mapo-Gu, Seoul 121-742 (Korea, Republic of); Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-Dong, Gangnam-Gu, Seoul 135-710 (Korea, Republic of); Lim, Hyun Keong; Kim, Sang Su [Department of Electronic Engineering, Sogang University, 1 Shinsu-Dong, Mapo-Gu, Seoul 121-742 (Korea, Republic of); Kim, Byung-Tae [Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-Dong, Gangnam-Gu, Seoul 135-710 (Korea, Republic of); Chung, Yonghyun [Department of Radiological Science, Yonsei University College of Health Science, 234 Meaji, Heungup Wonju, Kangwon-Do 220-710 (Korea, Republic of)

2012-02-01

Currently, for most photomultiplier tube (PMT)-based PET systems, constant fraction discriminators (CFD) and time to digital converters (TDC) have been employed to detect gamma ray signal arrival time, whereas anger logic circuits and peak detection analog-to-digital converters (ADCs) have been implemented to acquire position and energy information of detected events. As compared to PMT the Geiger-mode avalanche photodiodes (GAPDs) have a variety of advantages, such as compactness, low bias voltage requirement and MRI compatibility. Furthermore, the individual read-out method using a GAPD array coupled 1:1 with an array scintillator can provide better image uniformity than can be achieved using PMT and anger logic circuits. Recently, a brain PET using 72 GAPD arrays (4 Multiplication-Sign 4 array, pixel size: 3 mm Multiplication-Sign 3 mm) coupled 1:1 with LYSO scintillators (4 Multiplication-Sign 4 array, pixel size: 3 mm Multiplication-Sign 3 mm Multiplication-Sign 20 mm) has been developed for simultaneous PET/MRI imaging in our laboratory. Eighteen 64:1 position decoder circuits (PDCs) were used to reduce GAPD channel number and three off-the-shelf free-running ADC and field programmable gate array (FPGA) combined data acquisition (DAQ) cards were used for data acquisition and processing. In this study, a free-running ADC- and FPGA-based signal processing method was developed for the detection of gamma ray signal arrival time, energy and position information all together for each GAPD channel. For the method developed herein, three DAQ cards continuously acquired 18 channels of pre-amplified analog gamma ray signals and 108-bit digital addresses from 18 PDCs. In the FPGA, the digitized gamma ray pulses and digital addresses were processed to generate data packages containing pulse arrival time, baseline value, energy value and GAPD channel ID. Finally, these data packages were saved to a 128 Mbyte on-board synchronous dynamic random access memory (SDRAM) and

The preliminary study of 18F-FDG brain PET in diagnosis of alzheimer's disease

International Nuclear Information System (INIS)

Ma Yunchuan; Zhang Xinqing; Li Depeng; Shang Jianwen; Su Yusheng; Zhang Linying; Peng Cheng; Pan Zhongyun

2000-01-01

Objective: To investigate the imaging characteristics and diagnostic criteria of 18 F-FDG brain PET in diagnosis of Alzheimer's disease (AD). Methods: The sutdy included 12 normal subjects, 12 patients with AD and 11 patients with non-AD dementia. 40 min after intravenous administration of 18 F-FDG, brain scan was performed using Siemens ECAT47 scanner. The transaxial, coronal and sagittal images were then reconstructed by computer. At the same time, semiquantitative analysis was also applied to help evaluation using the ratio of mean radioactivity of cerebral lobe to cerebellum (R cl/cb ). Results: In normal subjects PET scan showed clear images of cerebral cortex, basal ganglia, thalamus and cerebellum with symmetrical distribution of radioactivity. PET images from Alzheimer's disease patients were classified into 3 patterns: bilateral parietal hypometabolism in 5 cases, bilateral temporo-parietal hypometabolism in 4 cases and unilateral temporo-parietal hypometabolism in 3 cases. The R cl/cb of AD patients in parietal and temporal lobe was significantly decreased than normal subjects (P cl/cb was also reflecting thedementia degree. Compared with MRI imaging , 12 patients with AD had cerebral hypometabolism but only 10 had hippocampus atrophy. 10 patients with non-AD dementia had local structural foci seen in MRI, including old hemorrhage, infarction and encephalomalacia, but these lesions were not found in AD. Conclusions: Based on excluding cerebral structural lesions which are better detected by MRI, bilateral or unilateral parietal or temporo-parietal hypometabolism found in FDG PET can be considered indicative of Alzheimer's disease. Semiquantitative analysis of the images yielded can help to evaluate the dementia degree

Markerless motion estimation for motion-compensated clinical brain imaging

Science.gov (United States)

Kyme, Andre Z.; Se, Stephen; Meikle, Steven R.; Fulton, Roger R.

2018-05-01

Motion-compensated brain imaging can dramatically reduce the artifacts and quantitative degradation associated with voluntary and involuntary subject head motion during positron emission tomography (PET), single photon emission computed tomography (SPECT) and computed tomography (CT). However, motion-compensated imaging protocols are not in widespread clinical use for these modalities. A key reason for this seems to be the lack of a practical motion tracking technology that allows for smooth and reliable integration of motion-compensated imaging protocols in the clinical setting. We seek to address this problem by investigating the feasibility of a highly versatile optical motion tracking method for PET, SPECT and CT geometries. The method requires no attached markers, relying exclusively on the detection and matching of distinctive facial features. We studied the accuracy of this method in 16 volunteers in a mock imaging scenario by comparing the estimated motion with an accurate marker-based method used in applications such as image guided surgery. A range of techniques to optimize performance of the method were also studied. Our results show that the markerless motion tracking method is highly accurate (brain imaging and holds good promise for a practical implementation in clinical PET, SPECT and CT systems.

11C-CHO PET in optimization of target volume delineation and treatment regimens in postoperative radiotherapy for brain gliomas

International Nuclear Information System (INIS)

Li Fangming; Nie Qing; Wang Ruimin; Chang, Susan M.; Zhao Wenrui; Zhu Qi; Liang Yingkui; Yang Ping; Zhang Jun; Jia Haiwei; Fang Henghu

2012-01-01

Objective: We explored the clinical values of 11 C-choline ( 11 C-CHO) PET in optimization of target volume delineation and treatment regimens in postoperative radiotherapy for brain gliomas. Methods: Sixteen patients with the pathological confirmation of the diagnosis of gliomas prior to receiving radiotherapy (postoperative) were included, and on whom both MRI and CHO PET scans were performed at the same position for comparison of residual tumors with the two techniques. 11 C-CHO was used as the tracer in the PET scan. A plain T1-weighted, T2-weighted and contrast-enhanced T1-weighted imaging scans were performed in the MRI scan sequence. The gliomas' residual tumor volume was defined as the area with CHO-PET high-affinity uptake and metabolism (V CHO ) and one with MRI T1-weighted imaging high signal intensity (V Gd ), and was determined by a group of experienced professionals and clinicians. Results: (1) In CHO-PET images, the tumor target volume, i.e., the highly metabolic area with a high concentration of isotopes (SUV 1.016–4.21) and the corresponding contralateral normal brain tissues (SUV0.1–0.62), was well contrasted, and the boundary between lesions and surrounding normal brain tissues was better defined compared with MRI and 18 F-FDG PET images. (2) For patients with brain gliomas of WHO Grade II, the SUV was 1.016–2.5; for those with WHO Grades III and IV, SUVs were >26–4.2. (3) Both CHO PET and MRI were positive for 10 patients and negative for 2 patients. The residual tumor consistency between these two studies was 75%. Four of the 10 CHO-PET-positive patients were negative on MRI scans. The maximum distance between V Gd and V CHO margins was 1.8 cm. (4) The gross tumor volumes (GTVs) and the ensuing treatment regimens were changed for 31.3% (5/16) of patients based on the CHO-PET high-affinity uptake and metabolism, in which the change rate was 80% (4/5), 14.3 % (1/7) and 0% (0/4) for patients with WHO Grade II III, and IV gliomas

PET brain imaging in HIV-associated neurocognitive disorders (HAND) in the era of combination antiretroviral therapy

Energy Technology Data Exchange (ETDEWEB)

Vera, Jaime H. [Brighton and Sussex Medical School, Department of Infection and Global Health, Brighton (United Kingdom); Brighton and Sussex University Hospitals NHS Trust, HIV Department, Brighton (United Kingdom); Ridha, Basil [Brighton and Sussex University Hospitals NHS Trust, Neurology Department, Brighton (United Kingdom); Gilleece, Yvonne; Amlani, Aliza [Brighton and Sussex University Hospitals NHS Trust, HIV Department, Brighton (United Kingdom); Thorburn, Patrick; Dizdarevic, Sabina [Brighton and Sussex University Hospitals NHS Trust, Imaging and Nuclear Medicine Department, Brighton (United Kingdom); Brighton and Sussex Medical School, Clinical Imaging Science Centre, Brighton (United Kingdom)

2017-05-15

Effective combination antiretroviral therapy (cART) has lead to a significant reduction in the prevalence and incidence of central nervous system (CNS) HIV-associated brain disease, particularly CNS opportunistic infections and HIV encephalitis. Despite this, cognitive deficits in people living with HIV, also known as HIV-associated neurocognitive disorders (HAND) have become more prevalent in recent years. The pathogenesis of HAND is likely to be multifactorial, however recent evidence suggests that brain microglial activation is the most likely pathogenic mechanism. Recent developments in positron emission tomography (PET) brain neuroimaging using novel brain radioligands targeting a variety of physiological changes in the brains of HIV-positive individuals have improved our understanding of the mechanisms associated with the development of HAND. This review will highlight recent PET brain neuroimaging studies in the cART era, focusing on physiological and neurochemical changes associated with HAND in people living with HIV. (orig.)

PET brain imaging in HIV-associated neurocognitive disorders (HAND) in the era of combination antiretroviral therapy

International Nuclear Information System (INIS)

Vera, Jaime H.; Ridha, Basil; Gilleece, Yvonne; Amlani, Aliza; Thorburn, Patrick; Dizdarevic, Sabina

2017-01-01

Effective combination antiretroviral therapy (cART) has lead to a significant reduction in the prevalence and incidence of central nervous system (CNS) HIV-associated brain disease, particularly CNS opportunistic infections and HIV encephalitis. Despite this, cognitive deficits in people living with HIV, also known as HIV-associated neurocognitive disorders (HAND) have become more prevalent in recent years. The pathogenesis of HAND is likely to be multifactorial, however recent evidence suggests that brain microglial activation is the most likely pathogenic mechanism. Recent developments in positron emission tomography (PET) brain neuroimaging using novel brain radioligands targeting a variety of physiological changes in the brains of HIV-positive individuals have improved our understanding of the mechanisms associated with the development of HAND. This review will highlight recent PET brain neuroimaging studies in the cART era, focusing on physiological and neurochemical changes associated with HAND in people living with HIV. (orig.)

Characterization of 4-[18F]-ADAM as an imaging agent for SERT in non-human primate brain using PET: a dynamic study

International Nuclear Information System (INIS)

Chen, Yu-An; Huang, Wen-Sheng; Lin, Yaoh-Shiang; Cheng, Cheng-Yi; Liu, Ren-Shyan; Wang, Shyh-Jen; Li, I-Hsun; Huang, San-Yuan; Shiue, Chyng-Yann; Chen, Cheng-Yu; Ma, Kuo-Hsing

2012-01-01

Introduction: Serotonin transporter (SERT) has been associated with many psychiatric diseases. This study investigated the biodistribution of a serotonin transporter imaging agent, N,N-dimethyl-2-(2-amino-4- 18 F-fluorophenylthio)benzylamine (4-[ 18 F]-ADAM), in nonhuman primate brain using positron emission tomography (PET). Methods: Six and four Macaca cyclopis monkeys were used to determine the transit time (i.e., time necessary to reach biodistribution equilibrium) and the reproducibility of 4-[ 18 F]-ADAM biodistribution in the brain, respectively. The sensitivity and specificity of 4-[ 18 F]-ADAM binding to SERT were evaluated in one monkey challenged with different doses of fluoxetine and one monkey treated with 3,4-methylendioxymethamphetamine (MDMA). Dynamic PET imaging was performed for 3 h after 4-[ 18 F]-ADAM intravenous bolus injection. The specific uptake ratios (SURs) in the midbrain (MB), thalamus (TH), striatum (ST) and frontal cortex (FC) were calculated. Results: The distribution of 4-[ 18 F]-ADAM reached equilibrium 120–150 min after injection. The mean SURs were 2.49±0.13 in MB, 1.59±0.17 in TH, 1.35±0.06 in ST and 0.34±0.03 in FC, and the minimum variability was shown 120–150 min after 4-[ 18 F]-ADAM injection. Using SURs and intraclass coefficient of correlation, the test/retest variability was under 8% and above 0.8, respectively, in SERT-rich areas. Challenge with fluoxetin (0.75–2 mg) dose-dependently inhibited the SURs in various brain regions. 4-[ 18 F]-ADAM binding was markedly reduced in the brain of an MDMA-treated monkey compared to that in brains of normal controls. Conclusion: 4-[ 18 F]-ADAM appears to be a highly selective radioligand for imaging SERT in monkey brain.

Intraindividual comparison of F-18-FLT PET and F-18 FET PET in brain tumor patients

International Nuclear Information System (INIS)

Kim, Sung Eun; Cheon, G. J.; Cho, Y. S.; Kwak, H. S.; Lee, C. H.; Choi, C. W.; Lim, S. M.

2003-01-01

To compare findings on FLT PET with FET PET, we prospectively undertaken FLT, FET and FDG PET in same patient with suspected primary/metastatic and recurrent brain tumors. Seventeen studies in 16 patients (47 8.3 years, M: F 10: 6) with brain tumor (3 for initial diagnosis, 6 for therapeutic response, 6 for detecting recurrence, 1 for diagnosis and recurrence both) were included. Brain tumors were 14 gliomas (6 high- grade 9 low-grade by the WHO classification), 2 metastatic brain tumors and 1 CNS lymphoma. 18F-FDG, FLT and FET PET were performed within two weeks. Attenuation-corrected brain images were acquired 30 minutes after injection of 370-555 MBq FDG, FLT and FET with a dedicated PET scanner (ECAT HR scanner, Siemens-CTI). Maximum SUV (max SUV) and relative uptake defined by FLT and FET accumulation within the tumor in relation to a contralateral control region (max SUV for tumor/ mean SUV for contralateral normal gray matter) were calculated. 26 tumor foci were analyzed. Relative FLT uptake (4.17 2.4, 0.58 to 7.45) was grater than than FET uptake (2.03 1.17, 0.92 to 4.53 (p<0.0006)) and FDG uptake (1.16 0.34, 0.76 to 2.08). Among FLT, FET and FDG uptakes in 20 tumor foci, correlation were poor. the relative FLT uptake of high-grade glioma was higher than low-glioma (6.070.76 vs 3.11 2.15, p=0.002), however, relative FET uptake was not different significantly (2.68 1.51, high-grade vs 1.970.78, low-grade). The correlation between tumor grade (high vs low grade) and relative uptake (FLT and FET) was shown only with relative FLT uptake (r=0.62, p=0.002). The best cut off value of relative FLT uptake between high-grade and low-grade glioma was 4.54 (AUC: 0.89 sensitivity: 100 specificity: 86.7%). Compared with FET uptake, FLT uptake showed much higher contrast and associated with tumor grade. Further study, evaluation of proliferative index of Ki-67 and its relationship with FLT and FET uptake, are ongoing

Effects of hypoxic–ischemic brain injury on striatal dopamine transporter in newborn piglets: evaluation of 11C-CFT PET/CT for DAT quantification

International Nuclear Information System (INIS)

Zhang Yanfen; Wang Xiaoyu; Cao Li; Guo Qiyong; Wang Xiaoming

2011-01-01

Introduction: Alterations of dopamine in striatal presynaptic terminals play an important role in the hypoxic–ischemic (HI) brain injury. Quantification of DAT levels in the presynaptic site using 11 C-N-2-carbomethoxy-3-(4-fluorophenyl)-tropane ( 11 C-CFT) with positron emission tomography (PET) was applied in studies for Parkinson's disease. The current study investigated the changes in striatal DAT following HI brain injury in newborn piglets using 11 C-CFT PET. Methods: Newborn piglets were subjected to occlusion of bilateral common carotid arteries for 30 min and simultaneous peripheral hypoxia. Brain DAT imaging was performed using PET/CT with 11 C-CFT as the probe in each group (including the control group and HI insult groups). Brain tissues were collected for DAT immunohistochemical (IHC) analysis at each time point post the PET/CT procedure. Sham controls had some operation without HI procedure. Results: A few minutes after intravenous injection of 11 C-CFT, radioactive signals for DAT clearly appeared in the cortical area, striatum and cerebellum of newborn piglets of sham control group and HI insult groups. HI brain insult markedly increased striatal DAT at an early period (P 11 C-CFT PET imaging data and IHC DAT staining data were highly correlated (r=0.844, P 11 C-CFT PET/CT imaging data reflected the dynamic changes of DAT in the striatum in vivo.

Anatomy assisted PET image reconstruction incorporating multi-resolution joint entropy

International Nuclear Information System (INIS)

Tang, Jing; Rahmim, Arman

2015-01-01

A promising approach in PET image reconstruction is to incorporate high resolution anatomical information (measured from MR or CT) taking the anato-functional similarity measures such as mutual information or joint entropy (JE) as the prior. These similarity measures only classify voxels based on intensity values, while neglecting structural spatial information. In this work, we developed an anatomy-assisted maximum a posteriori (MAP) reconstruction algorithm wherein the JE measure is supplied by spatial information generated using wavelet multi-resolution analysis. The proposed wavelet-based JE (WJE) MAP algorithm involves calculation of derivatives of the subband JE measures with respect to individual PET image voxel intensities, which we have shown can be computed very similarly to how the inverse wavelet transform is implemented. We performed a simulation study with the BrainWeb phantom creating PET data corresponding to different noise levels. Realistically simulated T1-weighted MR images provided by BrainWeb modeling were applied in the anatomy-assisted reconstruction with the WJE-MAP algorithm and the intensity-only JE-MAP algorithm. Quantitative analysis showed that the WJE-MAP algorithm performed similarly to the JE-MAP algorithm at low noise level in the gray matter (GM) and white matter (WM) regions in terms of noise versus bias tradeoff. When noise increased to medium level in the simulated data, the WJE-MAP algorithm started to surpass the JE-MAP algorithm in the GM region, which is less uniform with smaller isolated structures compared to the WM region. In the high noise level simulation, the WJE-MAP algorithm presented clear improvement over the JE-MAP algorithm in both the GM and WM regions. In addition to the simulation study, we applied the reconstruction algorithms to real patient studies involving DPA-173 PET data and Florbetapir PET data with corresponding T1-MPRAGE MRI images. Compared to the intensity-only JE-MAP algorithm, the WJE

Anatomy assisted PET image reconstruction incorporating multi-resolution joint entropy

Science.gov (United States)

Tang, Jing; Rahmim, Arman

2015-01-01

A promising approach in PET image reconstruction is to incorporate high resolution anatomical information (measured from MR or CT) taking the anato-functional similarity measures such as mutual information or joint entropy (JE) as the prior. These similarity measures only classify voxels based on intensity values, while neglecting structural spatial information. In this work, we developed an anatomy-assisted maximum a posteriori (MAP) reconstruction algorithm wherein the JE measure is supplied by spatial information generated using wavelet multi-resolution analysis. The proposed wavelet-based JE (WJE) MAP algorithm involves calculation of derivatives of the subband JE measures with respect to individual PET image voxel intensities, which we have shown can be computed very similarly to how the inverse wavelet transform is implemented. We performed a simulation study with the BrainWeb phantom creating PET data corresponding to different noise levels. Realistically simulated T1-weighted MR images provided by BrainWeb modeling were applied in the anatomy-assisted reconstruction with the WJE-MAP algorithm and the intensity-only JE-MAP algorithm. Quantitative analysis showed that the WJE-MAP algorithm performed similarly to the JE-MAP algorithm at low noise level in the gray matter (GM) and white matter (WM) regions in terms of noise versus bias tradeoff. When noise increased to medium level in the simulated data, the WJE-MAP algorithm started to surpass the JE-MAP algorithm in the GM region, which is less uniform with smaller isolated structures compared to the WM region. In the high noise level simulation, the WJE-MAP algorithm presented clear improvement over the JE-MAP algorithm in both the GM and WM regions. In addition to the simulation study, we applied the reconstruction algorithms to real patient studies involving DPA-173 PET data and Florbetapir PET data with corresponding T1-MPRAGE MRI images. Compared to the intensity-only JE-MAP algorithm, the WJE

Brain imaging for oxidative stress and mitochondrial dysfunction in neurodegenerative diseases

International Nuclear Information System (INIS)

Okazawa, H.; Tsujikawa, T.; Kiyono, Y.; Ikawa, M.; Yoneda, M.

2014-01-01

Oxidative stress, one of the most probable molecular mechanisms for neuronal impairment, is reported to occur in the affected brain regions of various neurodegenerative diseases. Recently, many studies showed evidence of a link between oxidative stress or mitochondrial damage and neuronal degeneration. Basic in vitro experiments and postmortem studies demonstrated that biomarkers for oxidative damage can be observed in the pathogenic regions of the brain and the affected neurons. Model animal studies also showed oxidative damage associated with neuronal degeneration. The molecular imaging method with positron emission tomography (PET) is expected to delineate oxidatively stressed microenvironments to elucidate pathophysiological changes of the in vivo brain; however, only a few studies have successfully demonstrated enhanced stress in patients. Radioisotope copper labeled diacetyl-bis(N4-methylthiosemicarbazone) (Cu-ATSM) may be the most promising candidate for this oxidative stress imaging. The tracer is usually known as a hypoxic tissue imaging PET probe, but the accumulation mechanism is based on the electron rich environment induced by mitochondrial impairment and/or microsomal over-reduction, and thus it is considered to represent the oxidative stress state correlated with the degree of disease severity. In this review, Cu-ATSM PET is introduced in detail from the basics to practical methods in clinical studies, as well as recent clinical studies on cerebrovascular diseases and neurodegenerative diseases. Several other PET probes are also introduced from the point of view of neuronal oxidative stress imaging. These molecular imaging methods should be promising tools to reveal oxidative injuries in various brain diseases

Pet imaging of peripheral benzodiazepine binding sites in brain tumors

International Nuclear Information System (INIS)

Junck, L.; Jewett, D.M.; Olsen, J.M.; Kilbourn, M.R.; Koeppe, R.A.; Young, A.B.; Greenberg, H.S.; Kuhl, D.E.

1991-01-01

Studies in vitro have shown that the peripheral-type benzodiazepine binding site (PBBS) is present in moderate to high density on malignant gliomas as well as in areas of reactive gliosis, but in low density in normal brain. PK 11195 is an isoquinoline derivative that binds selectively to the PBBS but not to the central benzodiazepine receptor. We have used [ 11 C]PK 11195 with positron emission tomography (PET) to study brain tumors and cerebral infarcts. Preliminary results showed that, in 13 of 18 patients with astrocytomas, [ 11 C]PK 11195 radioactivity was increased in tumor compared to remote brain and that the concentration ratios of tumor-to-remote brain were higher for high grade astrocytomas than for low grade astrocytomas. Pharmacokinetic analysis suggests that the increased activity in tumor probably does not result from alterations in blood flow or vascular permeability. Patients with lymphoma, meningioma, medulloblastoma, brain metastasis, and neurosarcoidosis have also shown increased radioactivity in tumor. Among eight patients with acute and subacute cerebral infarcts, activity in the infarct was increased in seven and was often greatest at the periphery. We conclude that [ 11 C]PK 11195 is a promising radiopharmaceutical for further investigation of brain tumors as well as diseases characterized by reactive gliosis

PET imaging of cerebral metabolic change in tinnitus using 18F-FDG

International Nuclear Information System (INIS)

Tian Jiahe; Wang Hongtian; Yin Dayi; Yao Shulin; Shao Mingzhe; Yang Weiyan; Jiang Sichang

2000-01-01

Tinnitus is an auditory disorder hardly assessable by clinical technology. PET imaging of the brain in 13 cases with and 10 without tinnitus was undertaken at 40 min after injection of 280-440 MBq 18 F-FDG. To ensure the quality of the PET study, all cases followed a normalized procedure with visual and auditory blockage. CT/MRI imaging and routine acoustic tests were carried out in all subjects. PET revealed that an increased uptake of 18 F-FDG at left med-temporal lobe (primary auditory center, PAC) present exclusively in tinnitus, regardless the side of hearing hallucination. Significant asymmetry was noted between left and right PAC, but not at other cortex area. While control cases showed no asymmetric uptake between two hemispheres. The abnormal PAC uptake did not respond to external pure sound stimulus, nor did it relate to the severity of hearing loss assessed by acoustic tests. No anatomical or morphological alteration could be proven on CT/MRI. In conclusion, PET/ 18 F-FDG objectively revealed an increased metabolic change at left PAC in tinnitus, which is of diagnostic value; and there is evidence suggesting tinnitus is most likely induced by a functional change in the brain

Current status of PET imaging in Huntington's disease

Energy Technology Data Exchange (ETDEWEB)

Pagano, Gennaro; Niccolini, Flavia; Politis, Marios [King' s College London, Neurodegeneration Imaging Group, Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), Camberwell, London (United Kingdom)

2016-06-15

To review the developments of recent decades and the current status of PET molecular imaging in Huntington's disease (HD). A systematic review of PET studies in HD was performed. The MEDLINE, Web of Science, Cochrane and Scopus databases were searched for articles in all languages published up to 19 August 2015 using the major medical subject heading ''Huntington Disease'' combined with text and key words ''Huntington Disease'', ''Neuroimaging'' and ''PET''. Only peer-reviewed, primary research studies in HD patients and premanifest HD carriers, and studies in which clinical features were described in association with PET neuroimaging results, were included in this review. Reviews, case reports and nonhuman studies were excluded. A total of 54 PET studies were identified and analysed in this review. Brain metabolism ([{sup 18}F]FDG and [{sup 15}O]H{sub 2}O), presynaptic ([{sup 18}F]fluorodopa, [{sup 11}C]β-CIT and [{sup 11}C]DTBZ) and postsynaptic ([{sup 11}C]SCH22390, [{sup 11}C]FLB457 and [{sup 11}C]raclopride) dopaminergic function, phosphodiesterases ([{sup 18}F]JNJ42259152, [{sup 18}F]MNI-659 and [{sup 11}C]IMA107), and adenosine ([{sup 18}F]CPFPX), cannabinoid ([{sup 18}F]MK-9470), opioid ([{sup 11}C]diprenorphine) and GABA ([{sup 11}C]flumazenil) receptors were evaluated as potential biomarkers for monitoring disease progression and for assessing the development and efficacy of novel disease-modifying drugs in premanifest HD carriers and HD patients. PET studies evaluating brain restoration and neuroprotection were also identified and described in detail. Brain metabolism, postsynaptic dopaminergic function and phosphodiesterase 10A levels were proven to be powerful in assessing disease progression. However, no single technique may be currently considered an optimal biomarker and an integrative multimodal imaging approach combining different techniques should be developed

Use of PET Images in Assessment of Brain Absorbed Dose of Patients Undergoing [C-11] Raclopride Positron Emission Tomography

International Nuclear Information System (INIS)

Park, Jong O

2005-08-01

The positron emission tomography (PET) in combination with [C-11] raclopride is commonly used for early detection of the Parkinson's disease. Injection of considerable amount of radioactivity, typically 300∼500 MBq of [C-11] at a time, for the examination calls for attention to doses to tissues of the patient, particularly to the brain. Since [C-11] raclopride is not a common radiopharmaceutical, dosimetric data for internal dose evaluation are rare yet. In this study, an attempt was made to determine doses to the brain and the striatum of patients by use of the PET images obtained for the clinical purposes. Four informed patients suffering Parkinson's disease participated in this study. Time series of 18 frames, 35 slices in each frame, of PET images of the head were obtained. By transforming the pixel intensity in the assigned region of interests into radioactivity contents, the retention curves were constructed to evaluate the residence times. Absorbed doses to the target tissues were calculated by applying the S-values given in the MIRDOSE3.1 code. The resulting dose coefficients for the whole brain and the striatum were 0.0110±0.0016 mGy/MBq and 0.0664±0.0238 mGy/MBq, respectively. The brain dose coefficient is considerably higher than the corresponding values in other studies employing healthy subjects. This may be attributed to probable enhanced capture of [C-11] raclopride by the dopamine D 2 receptors in case of subjects with Parkinson's disease. The transcrianial magnetic stimulation (TMS) procedures are often used in treatment of Parkinson's disease. If the procedure stimulates secretion of dopamine, less retention of [C-11] raclopride is expected due to competition. So the similar assessments were made for the same patients after TMS treatments. Disappointingly, the ratios of residence time without TMS to that with TMS were 0.943±0.074 and 0.98±0.14 for the brain and the striatum, respectively. For the striatum, the ratios for three patients were

Specification and estimation of sources of bias affecting neurological studies in PET/MR with an anatomical brain phantom

Science.gov (United States)

Teuho, J.; Johansson, J.; Linden, J.; Saunavaara, V.; Tolvanen, T.; Teräs, M.

2014-01-01

Selection of reconstruction parameters has an effect on the image quantification in PET, with an additional contribution from a scanner-specific attenuation correction method. For achieving comparable results in inter- and intra-center comparisons, any existing quantitative differences should be identified and compensated for. In this study, a comparison between PET, PET/CT and PET/MR is performed by using an anatomical brain phantom, to identify and measure the amount of bias caused due to differences in reconstruction and attenuation correction methods especially in PET/MR. Differences were estimated by using visual, qualitative and quantitative analysis. The qualitative analysis consisted of a line profile analysis for measuring the reproduction of anatomical structures and the contribution of the amount of iterations to image contrast. The quantitative analysis consisted of measurement and comparison of 10 anatomical VOIs, where the HRRT was considered as the reference. All scanners reproduced the main anatomical structures of the phantom adequately, although the image contrast on the PET/MR was inferior when using a default clinical brain protocol. Image contrast was improved by increasing the amount of iterations from 2 to 5 while using 33 subsets. Furthermore, a PET/MR-specific bias was detected, which resulted in underestimation of the activity values in anatomical structures closest to the skull, due to the MR-derived attenuation map that ignores the bone. Thus, further improvements for the PET/MR reconstruction and attenuation correction could be achieved by optimization of RAMLA-specific reconstruction parameters and implementation of bone to the attenuation template.

Quantitative simultaneous PET-MR imaging

Science.gov (United States)

Ouyang, Jinsong; Petibon, Yoann; Huang, Chuan; Reese, Timothy G.; Kolnick, Aleksandra L.; El Fakhri, Georges

2014-06-01

Whole-body PET is currently limited by the degradation due to patient motion. Respiratory motion degrades imaging studies of the abdomen. Similarly, both respiratory and cardiac motions significantly hamper the assessment of myocardial ischemia and/or metabolism in perfusion and viability cardiac PET studies. Based on simultaneous PET-MR, we have developed robust and accurate MRI methods allowing the tracking and measurement of both respiratory and cardiac motions during abdominal or cardiac studies. Our list-mode iterative PET reconstruction framework incorporates the measured motion fields into PET emission system matrix as well as the time-dependent PET attenuation map and the position dependent point spread function. Our method significantly enhances the PET image quality as compared to conventional methods.

3-D brain image registration using optimal morphological processing

International Nuclear Information System (INIS)

Loncaric, S.; Dhawan, A.P.

1994-01-01

The three-dimensional (3-D) registration of Magnetic Resonance (MR) and Positron Emission Tomographic (PET) images of the brain is important for analysis of the human brain and its diseases. A procedure for optimization of (3-D) morphological structuring elements, based on a genetic algorithm, is presented in the paper. The registration of the MR and PET images is done by means of a registration procedure in two major phases. In the first phase, the Iterative Principal Axis Transform (IPAR) is used for initial registration. In the second phase, the optimal shape description method based on the Morphological Signature Transform (MST) is used for final registration. The morphological processing is used to improve the accuracy of the basic IPAR method. The brain ventricle is used as a landmark for MST registration. A near-optimal structuring element obtained by means of a genetic algorithm is used in MST to describe the shape of the ventricle. The method has been tested on the set of brain images demonstrating the feasibility of approach. (author). 11 refs., 3 figs

Standardised uptake values from PET/CT images: comparison with conventional attenuation-corrected PET

International Nuclear Information System (INIS)

Souvatzoglou, M.; Ziegler, S.I.; Martinez, M.J.; Dzewas, G.; Schwaiger, M.; Bengel, F.; Busch, R.

2007-01-01

In PET/CT, CT-derived attenuation factors may influence standardised uptake values (SUVs) in tumour lesions and organs when compared with stand-alone PET. Therefore, we compared PET/CT-derived SUVs intra-individually in various organs and tumour lesions with stand-alone PET-derived SUVs. Thirty-five patients with known or suspected cancer were prospectively included. Sixteen patients underwent FDG PET using an ECAT HR+scanner, and subsequently a second scan using a Biograph Sensation 16PET/CT scanner. Nineteen patients were scanned in the reverse order. All images were reconstructed with an iterative algorithm (OSEM). Suspected lesions were grouped as paradiaphragmatic versus distant from the diaphragm. Mean and maximum SUVs were also calculated for brain, lung, liver, spleen and vertebral bone. The attenuation coefficients (μ values) used for correction of emission data (bone, soft tissue, lung) in the two data sets were determined. A body phantom containing six hot spheres and one cold cylinder was measured using the same protocol as in patients. Forty-six lesions were identified. There was a significant correlation of maximum and mean SUVs derived from PET and PET/CT for 14 paradiaphragmatic lesions (r=0.97 respectively; p<0.001 respectively) and for 32 lesions located distant from the diaphragm (r=0.87 and r=0.89 respectively; p<0.001 respectively). No significant differences were observed in the SUVs calculated with PET and PET/CT in the lesions or in the organs. In the phantom, radioactivity concentration in spheres calculated from PET and from PET/CT correlated significantly (r=0.99; p<0.001). SUVs of cancer lesions and normal organs were comparable between PET and PET/CT, supporting the usefulness of PET/CT-derived SUVs for quantification of tumour metabolism. (orig.)

Quantification of brain images using Korean standard templates and structural and cytoarchitectonic probabilistic maps

International Nuclear Information System (INIS)

Lee, Jae Sung; Lee, Dong Soo; Kim, Yu Kyeong

2004-01-01

Population based structural and functional maps of the brain provide effective tools for the analysis and interpretation of complex and individually variable brain data. Brain MRI and PET standard templates and statistical probabilistic maps based on image data of Korean normal volunteers have been developed and probabilistic maps based on cytoarchitectonic data have been introduced. A quantification method using these data was developed for the objective assessment of regional intensity in the brain images. Age, gender and ethnic specific anatomical and functional brain templates based on MR and PET images of Korean normal volunteers were developed. Korean structural probabilistic maps for 89 brain regions and cytoarchitectonic probabilistic maps for 13 Brodmann areas were transformed onto the standard templates. Brain FDG PET and SPGR MR images of normal volunteers were spatially normalized onto the template of each modality and gender. Regional uptake of radiotracers in PET and gray matter concentration in MR images were then quantified by averaging (or summing) regional intensities weighted using the probabilistic maps of brain regions. Regionally specific effects of aging on glucose metabolism in cingulate cortex were also examined. Quantification program could generate quantification results for single spatially normalized images per 20 seconds. Glucose metabolism change in cingulate gyrus was regionally specific: ratios of glucose metabolism in the rostral anterior cingulate vs. posterior cingulate and the caudal anterior cingulate vs. posterior cingulate were significantly decreased as the age increased. 'Rostral anterior' / 'posterior' was decreased by 3.1% per decade of age (p -11 , r=0.81) and 'caudal anterior' / 'posterior' was decreased by 1.7% (p -8 , r=0.72). Ethnic specific standard templates and probabilistic maps and quantification program developed in this study will be useful for the analysis of brain image of Korean people since the difference

Quantification of brain images using Korean standard templates and structural and cytoarchitectonic probabilistic maps

Energy Technology Data Exchange (ETDEWEB)

Lee, Jae Sung; Lee, Dong Soo; Kim, Yu Kyeong [College of Medicine, Seoul National Univ., Seoul (Korea, Republic of)] [and others

2004-06-01

Population based structural and functional maps of the brain provide effective tools for the analysis and interpretation of complex and individually variable brain data. Brain MRI and PET standard templates and statistical probabilistic maps based on image data of Korean normal volunteers have been developed and probabilistic maps based on cytoarchitectonic data have been introduced. A quantification method using these data was developed for the objective assessment of regional intensity in the brain images. Age, gender and ethnic specific anatomical and functional brain templates based on MR and PET images of Korean normal volunteers were developed. Korean structural probabilistic maps for 89 brain regions and cytoarchitectonic probabilistic maps for 13 Brodmann areas were transformed onto the standard templates. Brain FDG PET and SPGR MR images of normal volunteers were spatially normalized onto the template of each modality and gender. Regional uptake of radiotracers in PET and gray matter concentration in MR images were then quantified by averaging (or summing) regional intensities weighted using the probabilistic maps of brain regions. Regionally specific effects of aging on glucose metabolism in cingulate cortex were also examined. Quantification program could generate quantification results for single spatially normalized images per 20 seconds. Glucose metabolism change in cingulate gyrus was regionally specific: ratios of glucose metabolism in the rostral anterior cingulate vs. posterior cingulate and the caudal anterior cingulate vs. posterior cingulate were significantly decreased as the age increased. 'Rostral anterior' / 'posterior' was decreased by 3.1% per decade of age (p<10{sup -11}, r=0.81) and 'caudal anterior' / 'posterior' was decreased by 1.7% (p<10{sup -8}, r=0.72). Ethnic specific standard templates and probabilistic maps and quantification program developed in this study will be useful for the analysis

New method for extracting tumors in PET/CT images based on the probability distribution

International Nuclear Information System (INIS)

Nitta, Shuhei; Hontani, Hidekata; Hukami, Tadanori

2006-01-01

In this report, we propose a method for extracting tumors from PET/CT images by referring to the probability distribution of pixel values in the PET image. In the proposed method, first, the organs that normally take up fluorodeoxyglucose (FDG) (e.g., the liver, kidneys, and brain) are extracted. Then, the tumors are extracted from the images. The distribution of pixel values in PET images differs in each region of the body. Therefore, the threshold for detecting tumors is adaptively determined by referring to the distribution. We applied the proposed method to 37 cases and evaluated its performance. This report also presents the results of experiments comparing the proposed method and another method in which the pixel values are normalized for extracting tumors. (author)

PET/MRI: a novel hybrid imaging technique: major clinical indications and preliminary experience in Brazil; PET/RM: um novo metodo de imagem hibrida: principais indicacoes clinicas e experiencia preliminar no Brasil

Energy Technology Data Exchange (ETDEWEB)

Vitor, Taise; Martins, Karine Minaif; Ionescu, Tudor Mihai and others, E-mail: taisevitor@gmail.com [Hospital Israelita Albert Einstein, Sao Paulo, SP (Brazil)

2017-04-01

In recent years, medical imaging with hybrid techniques has widely accepted and employed in clinical routine. PET/MRI offers significant advantages, including excellent contrast and resolution and reduced ionizing radiation, as compared to well-established PET/ CT. Therefore, PET/MRI is a promising modality for oncologic imaging of some regions, such as brain, head and neck, liver and pelvis. This article set out to analyze clinical conditions that could benefit from PET/MRI imaging based on our caseload. The potential of PET/MRI to become the imaging modality of choice for assessment of neurologic and oncologic conditions associated with soft tissues is highlighted. Clinical aspects of PET/MRI and its application to clinical cases are illustrated with examples extracted from the authors' preliminary experience. (author)

SPAM-assisted partial volume correction algorithm for PET

Energy Technology Data Exchange (ETDEWEB)

Cho, Sung Il; Kang, Keon Wook; Lee, Jae Sung; Lee, Dong Soo; Chung, June Key; Soh, Kwang Sup; Lee, Myung Chul [College of Medicine, Seoul National Univ., Seoul (Korea, Republic of)

2000-07-01

A probabilistic atlas of the human brain (Statistical Probability Anatomical Maps: SPAM) was developed by the International Consortium for Brain Mapping (ICBM). It will be a good frame for calculating volume of interest (VOI) according to statistical variability of human brain in many fields of brain images. We show that we can get more exact quantification of the counts in VOI by using SPAM in the correlation of partial volume effect for simulated PET image. The MRI of a patient with dementia was segmented into gray matter and white matter, and then they were smoothed to PET resolution. Simulated PET image was made by adding one third of the smoothed white matter to the smoothed gray matter. Spillover effect and partial volume effect were corrected for this simulated PET image with the aid of the segmented and smoothed MR images. The images were spatially normalized to the average brain MRI atlas of ICBM, and were multiplied by the probablities of 98 VOIs of SPAM images of Montreal Neurological Institute. After the correction of partial volume effect, the counts of frontal, partietal, temporal, and occipital lobes were increased by 38{+-}6%, while those of hippocampus and amygdala by 4{+-}3%. By calculating the counts in VOI using the product of probability of SPAM images and counts in the simulated PET image, the counts increase and become closer to the true values. SPAM-assisted partial volume correction is useful for quantification of VOIs in PET images.

SPAM-assisted partial volume correction algorithm for PET

International Nuclear Information System (INIS)

Cho, Sung Il; Kang, Keon Wook; Lee, Jae Sung; Lee, Dong Soo; Chung, June Key; Soh, Kwang Sup; Lee, Myung Chul

2000-01-01

A probabilistic atlas of the human brain (Statistical Probability Anatomical Maps: SPAM) was developed by the International Consortium for Brain Mapping (ICBM). It will be a good frame for calculating volume of interest (VOI) according to statistical variability of human brain in many fields of brain images. We show that we can get more exact quantification of the counts in VOI by using SPAM in the correlation of partial volume effect for simulated PET image. The MRI of a patient with dementia was segmented into gray matter and white matter, and then they were smoothed to PET resolution. Simulated PET image was made by adding one third of the smoothed white matter to the smoothed gray matter. Spillover effect and partial volume effect were corrected for this simulated PET image with the aid of the segmented and smoothed MR images. The images were spatially normalized to the average brain MRI atlas of ICBM, and were multiplied by the probablities of 98 VOIs of SPAM images of Montreal Neurological Institute. After the correction of partial volume effect, the counts of frontal, partietal, temporal, and occipital lobes were increased by 38±6%, while those of hippocampus and amygdala by 4±3%. By calculating the counts in VOI using the product of probability of SPAM images and counts in the simulated PET image, the counts increase and become closer to the true values. SPAM-assisted partial volume correction is useful for quantification of VOIs in PET images

Translocator Protein-18 kDa (TSPO Positron Emission Tomography (PET Imaging and Its Clinical Impact in Neurodegenerative Diseases

Directory of Open Access Journals (Sweden)

Anne-Claire Dupont

2017-04-01

Full Text Available In vivo exploration of activated microglia in neurodegenerative diseases is achievable by Positron Emission Tomography (PET imaging, using dedicated radiopharmaceuticals targeting the translocator protein-18 kDa (TSPO. In this review, we emphasized the major advances made over the last 20 years, thanks to TSPO PET imaging, to define the pathophysiological implication of microglia activation and neuroinflammation in neurodegenerative diseases, including Parkinson’s disease, Huntington’s disease, dementia, amyotrophic lateral sclerosis, multiple sclerosis, and also in psychiatric disorders. The extent and upregulation of TSPO as a molecular biomarker of activated microglia in the human brain is now widely documented in these pathologies, but its significance, and especially its protective or deleterious action regarding the disease’s stage, remains under debate. Thus, we exposed new and plausible suggestions to enhance the contribution of TSPO PET imaging for biomedical research by exploring microglia’s role and interactions with other cells in brain parenchyma. Multiplex approaches, associating TSPO PET radiopharmaceuticals with other biomarkers (PET imaging of cellular metabolism, neurotransmission or abnormal protein aggregates, but also other imaging modalities, and peripheral cytokine levels measurement and/or metabolomics analysis was considered. Finally, the actual clinical impact of TSPO PET imaging as a routine biomarker of neuroinflammation was put into perspective regarding the current development of diagnostic and therapeutic strategies for neurodegenerative diseases.

Comparison between MRI-based attenuation correction methods for brain PET in dementia patients

International Nuclear Information System (INIS)

Cabello, Jorge; Lukas, Mathias; Pyka, Thomas; Nekolla, Stephan G.; Ziegler, Sibylle I.; Rota Kops, Elena; Shah, N. Jon; Ribeiro, Andre; Yakushev, Igor

2016-01-01

The combination of Positron Emission Tomography (PET) with magnetic resonance imaging (MRI) in hybrid PET/MRI scanners offers a number of advantages in investigating brain structure and function. A critical step of PET data reconstruction is attenuation correction (AC). Accounting for bone in attenuation maps (μ-map) was shown to be important in brain PET studies. While there are a number of MRI-based AC methods, no systematic comparison between them has been performed so far. The aim of this work was to study the different performance obtained by some of the recent methods presented in the literature. To perform such a comparison, we focused on [ 18 F]-Fluorodeoxyglucose-PET/MRI neurodegenerative dementing disorders, which are known to exhibit reduced levels of glucose metabolism in certain brain regions. Four novel methods were used to calculate μ-maps from MRI data of 15 patients with Alzheimer's dementia (AD). The methods cover two atlas-based methods, a segmentation method, and a hybrid template/segmentation method. Additionally, the Dixon-based and a UTE-based method, offered by a vendor, were included in the comparison. Performance was assessed at three levels: tissue identification accuracy in the μ-map, quantitative accuracy of reconstructed PET data in specific brain regions, and precision in diagnostic images at identifying hypometabolic areas. Quantitative regional errors of -20-10 % were obtained using the vendor's AC methods, whereas the novel methods produced errors in a margin of ±5 %. The obtained precision at identifying areas with abnormally low levels of glucose uptake, potentially regions affected by AD, were 62.9 and 79.5 % for the two vendor AC methods, the former ignoring bone and the latter including bone information. The precision increased to 87.5-93.3 % in average for the four new methods, exhibiting similar performances. We confirm that the AC methods based on the Dixon and UTE sequences provided by the vendor are inferior

Comparison between MRI-based attenuation correction methods for brain PET in dementia patients

Energy Technology Data Exchange (ETDEWEB)

Cabello, Jorge; Lukas, Mathias; Pyka, Thomas; Nekolla, Stephan G.; Ziegler, Sibylle I. [Technische Universitaet Muenchen, Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Munich (Germany); Rota Kops, Elena; Shah, N. Jon [Forschungszentrum Juelich GmbH, Institute of Neuroscience and Medicine 4, Medical Imaging Physics, Juelich (Germany); Ribeiro, Andre [Forschungszentrum Juelich GmbH, Institute of Neuroscience and Medicine 4, Medical Imaging Physics, Juelich (Germany); Institute of Biophysics and Biomedical Engineering, Lisbon (Portugal); Yakushev, Igor [Technische Universitaet Muenchen, Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Munich (Germany); Institute TUM Neuroimaging Center (TUM-NIC), Munich (Germany)

2016-11-15

The combination of Positron Emission Tomography (PET) with magnetic resonance imaging (MRI) in hybrid PET/MRI scanners offers a number of advantages in investigating brain structure and function. A critical step of PET data reconstruction is attenuation correction (AC). Accounting for bone in attenuation maps (μ-map) was shown to be important in brain PET studies. While there are a number of MRI-based AC methods, no systematic comparison between them has been performed so far. The aim of this work was to study the different performance obtained by some of the recent methods presented in the literature. To perform such a comparison, we focused on [{sup 18}F]-Fluorodeoxyglucose-PET/MRI neurodegenerative dementing disorders, which are known to exhibit reduced levels of glucose metabolism in certain brain regions. Four novel methods were used to calculate μ-maps from MRI data of 15 patients with Alzheimer's dementia (AD). The methods cover two atlas-based methods, a segmentation method, and a hybrid template/segmentation method. Additionally, the Dixon-based and a UTE-based method, offered by a vendor, were included in the comparison. Performance was assessed at three levels: tissue identification accuracy in the μ-map, quantitative accuracy of reconstructed PET data in specific brain regions, and precision in diagnostic images at identifying hypometabolic areas. Quantitative regional errors of -20-10 % were obtained using the vendor's AC methods, whereas the novel methods produced errors in a margin of ±5 %. The obtained precision at identifying areas with abnormally low levels of glucose uptake, potentially regions affected by AD, were 62.9 and 79.5 % for the two vendor AC methods, the former ignoring bone and the latter including bone information. The precision increased to 87.5-93.3 % in average for the four new methods, exhibiting similar performances. We confirm that the AC methods based on the Dixon and UTE sequences provided by the vendor are

Imaging neurochemistry of cerebrovascular disease with PET and SPECT

International Nuclear Information System (INIS)

Hatazawa, J.; Shimosegawa, E.

1998-01-01

Pathophysiology od cerebrovascular disease has been studied by measuring cerebral blood flow and energy metabolism using single photon emission computed tomography (SPECT) and positron emission tomography (PET). These parameters are measures for brain tissue consisting of heterogeneous components such as neurons, glial cells, and blood vessels. It is still difficult to evaluate brain damages specifically involving either neurons or other components. Several trials were recently conducted to visualize neuron-specific injury in cerebrovascular disease by means of 11 C flumazenil for PET and 123 I-iomazenil for SPECT. These tracers selectively bind to central benzodiazepine receptor which is purely neuronal. A reduced accumulation of these ligands was found in the area surrounding the complete infarction and in the cortex remote from putaminal hemorrhage, indicating the existence of neuron specific injury not visualized by CT and MR. Neurological deficits were well correlated with the loss of cortical accumulation of these ligands. These preliminary studies indicated a potential of neurochemical imaging in cerebrovascular disease. Vulnerability to ischemia which may differ among brain tissue components, among subpopulations of neurons, and among pre-synaptic and post-synaptic functions can be more precisely examined. Neurochemical imaging can be also applied to reveal releases and re-organization of each neurotransmitter-acceptor system after stroke

Imaging neurochemistry of cerebrovascular disease with PET and SPECT

Energy Technology Data Exchange (ETDEWEB)

Hatazawa, J.; Shimosegawa, E. [Akita Research Institute of Brain and Blood Vessels, Akita (Japan). Dept. of Radiology and Nuclear Medicine

1998-09-01

Pathophysiology od cerebrovascular disease has been studied by measuring cerebral blood flow and energy metabolism using single photon emission computed tomography (SPECT) and positron emission tomography (PET). These parameters are measures for brain tissue consisting of heterogeneous components such as neurons, glial cells, and blood vessels. It is still difficult to evaluate brain damages specifically involving either neurons or other components. Several trials were recently conducted to visualize neuron-specific injury in cerebrovascular disease by means of {sup 11}C flumazenil for PET and {sup 123}I-iomazenil for SPECT. These tracers selectively bind to central benzodiazepine receptor which is purely neuronal. A reduced accumulation of these ligands was found in the area surrounding the complete infarction and in the cortex remote from putaminal hemorrhage, indicating the existence of neuron specific injury not visualized by CT and MR. Neurological deficits were well correlated with the loss of cortical accumulation of these ligands. These preliminary studies indicated a potential of neurochemical imaging in cerebrovascular disease. Vulnerability to ischemia which may differ among brain tissue components, among subpopulations of neurons, and among pre-synaptic and post-synaptic functions can be more precisely examined. Neurochemical imaging can be also applied to reveal releases and re-organization of each neurotransmitter-acceptor system after stroke.

A multi-atlas based method for automated anatomical rat brain MRI segmentation and extraction of PET activity.

Science.gov (United States)

Lancelot, Sophie; Roche, Roxane; Slimen, Afifa; Bouillot, Caroline; Levigoureux, Elise; Langlois, Jean-Baptiste; Zimmer, Luc; Costes, Nicolas

2014-01-01

Preclinical in vivo imaging requires precise and reproducible delineation of brain structures. Manual segmentation is time consuming and operator dependent. Automated segmentation as usually performed via single atlas registration fails to account for anatomo-physiological variability. We present, evaluate, and make available a multi-atlas approach for automatically segmenting rat brain MRI and extracting PET activies. High-resolution 7T 2DT2 MR images of 12 Sprague-Dawley rat brains were manually segmented into 27-VOI label volumes using detailed protocols. Automated methods were developed with 7/12 atlas datasets, i.e. the MRIs and their associated label volumes. MRIs were registered to a common space, where an MRI template and a maximum probability atlas were created. Three automated methods were tested: 1/registering individual MRIs to the template, and using a single atlas (SA), 2/using the maximum probability atlas (MP), and 3/registering the MRIs from the multi-atlas dataset to an individual MRI, propagating the label volumes and fusing them in individual MRI space (propagation & fusion, PF). Evaluation was performed on the five remaining rats which additionally underwent [18F]FDG PET. Automated and manual segmentations were compared for morphometric performance (assessed by comparing volume bias and Dice overlap index) and functional performance (evaluated by comparing extracted PET measures). Only the SA method showed volume bias. Dice indices were significantly different between methods (PF>MP>SA). PET regional measures were more accurate with multi-atlas methods than with SA method. Multi-atlas methods outperform SA for automated anatomical brain segmentation and PET measure's extraction. They perform comparably to manual segmentation for FDG-PET quantification. Multi-atlas methods are suitable for rapid reproducible VOI analyses.

Quantitative assessment of dynamic PET imaging data in cancer imaging.

Science.gov (United States)

Muzi, Mark; O'Sullivan, Finbarr; Mankoff, David A; Doot, Robert K; Pierce, Larry A; Kurland, Brenda F; Linden, Hannah M; Kinahan, Paul E

2012-11-01

Clinical imaging in positron emission tomography (PET) is often performed using single-time-point estimates of tracer uptake or static imaging that provides a spatial map of regional tracer concentration. However, dynamic tracer imaging can provide considerably more information about in vivo biology by delineating both the temporal and spatial pattern of tracer uptake. In addition, several potential sources of error that occur in static imaging can be mitigated. This review focuses on the application of dynamic PET imaging to measuring regional cancer biologic features and especially in using dynamic PET imaging for quantitative therapeutic response monitoring for cancer clinical trials. Dynamic PET imaging output parameters, particularly transport (flow) and overall metabolic rate, have provided imaging end points for clinical trials at single-center institutions for years. However, dynamic imaging poses many challenges for multicenter clinical trial implementations from cross-center calibration to the inadequacy of a common informatics infrastructure. Underlying principles and methodology of PET dynamic imaging are first reviewed, followed by an examination of current approaches to dynamic PET image analysis with a specific case example of dynamic fluorothymidine imaging to illustrate the approach. Copyright © 2012 Elsevier Inc. All rights reserved.

Electromagnetic brain imaging

International Nuclear Information System (INIS)

Sekihara, Kensuke

2008-01-01

Present imaging methods of cerebral neuro-activity like brain functional MRI and positron emission tomography (PET) secondarily measure only average activities within a time of the second-order (low time-resolution). In contrast, the electromagnetic brain imaging (EMBI) directly measures the faint magnetic field (10 -12 -10 -13 T) yielded by the cerebral activity with use of multiple arrayed sensors equipped on the head surface within a time of sub-millisecond order (high time-resolution). The sensor array technology to find the signal source from the measured data is common in wide areas like signal procession for radar, sonar, and epicenter detection by seismic wave. For estimating and reconstructing the active region in the brain in EMBI, the efficient method must be developed and this paper describes the direct and inverse problems concerned in signal and image processions of EMBI. The direct problem involves the cerebral magnetic field/lead field matrix and inverse problem for reconstruction of signal source, the MUSIC (multiple signal classification) algorithm, GLRT (generalized likelihood ratio test) scan, and adaptive beamformer. As an example, given are results of magnetic intensity changes (unit, fT) in the somatosensory cortex vs time (msec) measured by 160 sensors and of images reconstructed from EMBI and MRI during electric muscle afferent input from the hand. The real-time imaging is thus possible with EMBI and extremely, the EMBI image, the real-time cerebral signals, can inversely operate a machine, of which application directs toward the brain/machine interface development. (R.T.)

PET molecular imaging in stem cell therapy for neurological diseases

Energy Technology Data Exchange (ETDEWEB)

Wang, Jiachuan; Zhang, Hong [Second Affiliated Hospital of Zhejiang University School of Medicine, Department of Nuclear Medicine, Hangzhou, Zhejiang (China); Zhejiang University, Medical PET Center, Hangzhou (China); Institute of Nuclear Medicine and Molecular Imaging of Zhejiang University, Hangzhou (China); Key Laboratory of Medical Molecular Imaging of Zhejiang Province, Hangzhou (China); Tian, Mei [University of Texas, M.D. Anderson Cancer Center, Department of Experimental Diagnostic Imaging, Houston, TX (United States)

2011-10-15

Human neurological diseases such as Alzheimer's disease, Parkinson's disease, Huntington's disease, spinal cord injury and multiple sclerosis are caused by loss of different types of neurons and glial cells in the brain and spinal cord. At present, there are no effective therapies against these disorders. Discovery of the therapeutic potential of stem cells offers new strategies for the treatment of neurological diseases. Direct assessment of stem cells' survival, interaction with the host and impact on neuronal functions after transplantation requires advanced in vivo imaging techniques. Positron emission tomography (PET) is a potential molecular imaging modality to evaluate the viability and function of transplanted tissue or stem cells in the nervous system. This review focuses on PET molecular imaging in stem cell therapy for neurological diseases. (orig.)

Practical Considerations for Clinical PET/MR Imaging.

Science.gov (United States)

Galgano, Samuel; Viets, Zachary; Fowler, Kathryn; Gore, Lael; Thomas, John V; McNamara, Michelle; McConathy, Jonathan

2018-01-01

Clinical PET/MR imaging is currently performed at a number of centers around the world as part of routine standard of care. This article focuses on issues and considerations for a clinical PET/MR imaging program, focusing on routine standard-of-care studies. Although local factors influence how clinical PET/MR imaging is implemented, the approaches and considerations described here intend to apply to most clinical programs. PET/MR imaging provides many more options than PET/computed tomography with diagnostic advantages for certain clinical applications but with added complexity. A recurring theme is matching the PET/MR imaging protocol to the clinical application to balance diagnostic accuracy with efficiency. Copyright © 2017 Elsevier Inc. All rights reserved.

Evaluation of deep brain stimulation for Parkinson's disease by using FDG PET

International Nuclear Information System (INIS)

Guan, Y.H.; Zuo, C.T.; Zhao, J.; Lin, X.T.; Sun, B.M.

2002-01-01

Objective: Patients are effectively treated with medication in their initial phases of Parkinson's disease. However, the drugs become less effective and the adverse effects revealed. Recent years, the chronic deep brain stimulation is becoming an important treatment for patients with patients with Parkinson's disease. It has shown that the Parkinson's state is characterized by pathological neural activity in the motor system including the internal segment of the globus pallidus (GPi) and the subthalamic nucleus (STN). The chronic deep brain stimulation can make benefits in the patients by intermediate the pathological neural activity. It needs an external method to evaluate the mechanism of therapy and to monitor the effect of treatment. The objective of our study is to observe the regional glucose metabolism changes in the motor loops and demonstrate the mechanism of therapy and how to monitor the treatment. Patients and Methods: Employing FDG PET, we had studied 7 patients who suffered from Parkinson's disease all the patients were failing medical therapy.the electrodes were implanted in the brain by the direction of MRI.The target of DBS is STN. Resting FDG PET were performed on and off STN stimulation. Metabolic changes with DBS were correlated with clinical improvement as measured by changes in Unified Parkinson's Disease Rating Scale (UPDRS) motor ratings off medication. PET imaging was read by visual interpretation in blind method and calculated by semi-quantitative analysis. The statistic data was analysis after FDG PET imaging. Results: Through the research, regional cerebral glucose metabolic changes with DBS on and off were correlated with clinical improvement as measured by changes in Unified Parkinson's Disease Rating Scale (UPDRS) motor ratings. STN DBS improved UPDRS motor ratings (33%, P<0.001) and significantly increased regional glucose metabolism in the frontal lobe, temporal lobe, Parietal lobe cortex ipsilateral to stimulation. The heighten

Obsessive-compulsive disorder: advances in brain imaging; Trastornos obsesivos compulsivos (TOC): avances imagenologicos

Energy Technology Data Exchange (ETDEWEB)

Galli, Enrique [Departamento de Psiquiatria de la Univeversidad Peruana Cayetano Heredia, San Isidro, Lima (Peru)

2000-07-01

In the past twenty years functional brain imaging has advanced to the point of tackling the differential diagnosis, prognosis and therapeutic response in Neurology and Psychiatry. Psychiatric disorders were rendered 'functional' a century ago; however nowadays they can be seen by means of brain imaging. Functional images in positron emission tomography (PET) and single photon emission tomography (NEUROSPET) show in non-invasive fashion the state of brain functioning. PET does this assessing glucose metabolism and NEUROSPET by putting cerebral blood flow in images. Prevalence of OCD is clearly low (2 to 3%), but comorbidity with depression, psychoses, bipolar disorder and schizophrenia is high. Furthermore, it is not infrequent with autism, attention disorder, tichotillomany, borderline personality disorders, in pathological compulsive spending, sexual compulsion and in pathological gambling, in tics, and in Gilles de la Tourette disorder, NEUROSPET and PET show hypoperfusion in both frontal lobes, in their prefrontal dorsolateral aspects, in their inferior zone and premotor cortex, with hyperperfusion in the posterior cingulum and hypoperfusion in basal ganglia (caudate nucleus). Cummings states that hyperactivity of the limbic system might be involved in OCD. Thus, brain imaging in OCD is a diagnostic aid, allows us to see clinical imagenological evolution and therapeutic response and, possibly, it is useful predict therapeutic response (Au)

Targeting MT1-MMP as an ImmunoPET-Based Strategy for Imaging Gliomas.

Directory of Open Access Journals (Sweden)

A G de Lucas

Full Text Available A critical challenge in the management of Glioblastoma Multiforme (GBM tumors is the accurate diagnosis and assessment of tumor progression in a noninvasive manner. We have identified Membrane-type 1 matrix metalloproteinase (MT1-MMP as an attractive biomarker for GBM imaging since this protein is actively involved in tumor growth and progression, correlates with tumor grade and is closely associated with poor prognosis in GBM patients. Here, we report the development of an immunoPET tracer for effective detection of MT1-MMP in GBM models.An anti-human MT1-MMP monoclonal antibody (mAb, LEM2/15, was conjugated to p-isothiocyanatobenzyl-desferrioxamine (DFO-NCS for 89Zr labeling. Biodistribution and PET imaging studies were performed in xenograft mice bearing human GBM cells (U251 expressing MT1-MMP and non-expressing breast carcinoma cells (MCF-7 as negative control. Two orthotopic brain GBM models, patient-derived neurospheres (TS543 and U251 cells, with different degrees of blood-brain barrier (BBB disruption were also used for PET imaging experiments.89Zr labeling of DFO-LEM2/15 was achieved with high yield (>90% and specific activity (78.5 MBq/mg. Biodistribution experiments indicated that 89Zr-DFO-LEM2/15 showed excellent potential as a radiotracer for detection of MT1-MMP positive GBM tumors. PET imaging also indicated a specific and prominent 89Zr-DFO-LEM2/15 uptake in MT1-MMP+ U251 GBM tumors compared to MT1-MMP- MCF-7 breast tumors. Results obtained in orthotopic brain GBM models revealed a high dependence of a disrupted BBB for tracer penetrance into tumors. 89Zr-DFO-LEM2/15 showed much higher accumulation in TS543 tumors with a highly disrupted BBB than in U251 orthotopic model in which the BBB permeability was only partially increased. Histological analysis confirmed the specificity of the immunoconjugate in all GBM models.A new anti MT1-MMP-mAb tracer, 89Zr-DFO-LEM2/15, was synthesized efficiently. In vivo validation showed high

Simultaneous PET and MR imaging

International Nuclear Information System (INIS)

Yiping Shao; Cherry, Simon R.; Meadors, Ken; Siegel, Stefan; Silverman, Robert W.; Farahani, Keyvan; Marsden, Paul K.

1997-01-01

We have developed a prototype PET detector which is compatible with a clinical MRI system to provide simultaneous PET and MR imaging. This single-slice PET system consists of 48 2x2x10mm 3 LSO crystals in a 38 mm diameter ring configuration that can be placed inside the receiver coil of the MRI system, coupled to three multi-channel photomultipliers housed outside the main magnetic field via 4 m long and 2 mm diameter optical fibres. The PET system exhibits 2 mm spatial resolution, 41% energy resolution at 511 keV and 20 ns timing resolution. Simultaneous PET and MR phantom images were successfully acquired. (author)

A fully automatic approach for multimodal PET and MR image segmentation in gamma knife treatment planning.

Science.gov (United States)

Rundo, Leonardo; Stefano, Alessandro; Militello, Carmelo; Russo, Giorgio; Sabini, Maria Gabriella; D'Arrigo, Corrado; Marletta, Francesco; Ippolito, Massimo; Mauri, Giancarlo; Vitabile, Salvatore; Gilardi, Maria Carla

2017-06-01

Nowadays, clinical practice in Gamma Knife treatments is generally based on MRI anatomical information alone. However, the joint use of MRI and PET images can be useful for considering both anatomical and metabolic information about the lesion to be treated. In this paper we present a co-segmentation method to integrate the segmented Biological Target Volume (BTV), using [ 11 C]-Methionine-PET (MET-PET) images, and the segmented Gross Target Volume (GTV), on the respective co-registered MR images. The resulting volume gives enhanced brain tumor information to be used in stereotactic neuro-radiosurgery treatment planning. GTV often does not match entirely with BTV, which provides metabolic information about brain lesions. For this reason, PET imaging is valuable and it could be used to provide complementary information useful for treatment planning. In this way, BTV can be used to modify GTV, enhancing Clinical Target Volume (CTV) delineation. A novel fully automatic multimodal PET/MRI segmentation method for Leksell Gamma Knife ® treatments is proposed. This approach improves and combines two computer-assisted and operator-independent single modality methods, previously developed and validated, to segment BTV and GTV from PET and MR images, respectively. In addition, the GTV is utilized to combine the superior contrast of PET images with the higher spatial resolution of MRI, obtaining a new BTV, called BTV MRI . A total of 19 brain metastatic tumors, undergone stereotactic neuro-radiosurgery, were retrospectively analyzed. A framework for the evaluation of multimodal PET/MRI segmentation is also presented. Overlap-based and spatial distance-based metrics were considered to quantify similarity concerning PET and MRI segmentation approaches. Statistics was also included to measure correlation among the different segmentation processes. Since it is not possible to define a gold-standard CTV according to both MRI and PET images without treatment response assessment

Functional brain imaging - baric and clinical questions

International Nuclear Information System (INIS)

Mager, T.; Moeller, H.J.

1997-01-01

The advancing biological knowledge of disease processes plays a central part in the progress of modern psychiatry. An essential contribution comes from the functional and structural brain imaging techniques (CT, MRI, SPECT, PET). Their application is important for biological oriented research in psychiatry and there is also a growing relevance in clinical aspects. This development is taken into account by recent diagnostic classification systems in psychiatry. The capabilities and limitations of functional brain imaging in the context of research and clinic will be presented and discussed by examples and own investigations. (orig.) [de

Registration of SPECT, PET and/or X-ray CT images in patients with lung cancer

International Nuclear Information System (INIS)

Uemura, K.; Toyama, H.; Miyamoto, T.; Yoshikawa, K.; Mori, Y.

2002-01-01

Aim: In order to evaluate the therapeutic gain of heavy ion therapy performed on patients with lung cancer, the regional pulmonary functions and the amount of radio tracer accumulation to the tumor, we are investigated by using the region of interest based on anatomical information obtained from X-ray CT. There are many registration techniques for brain images, but not so much for the other organ images that we have studied registration of chest SPECT, PET and/or X-ray CT images. Materials and Methods: Perfusion, ventilation and blood pool images with Tc 99m labeled radiopharmaceuticals and SPECT, tumor images with 11 C-methionine and PET and X-ray CT scans were performed on several patients with lung cancer before and after heavy ion therapy. The registrations of SPECT-CT, PET-CT and CT-CT were performed by using AMIR (Automatic Multimodality Image Registration), which was developed by Babak et al. for registration of brain images. In a case of SPECT-CT registration, each of the three functional images was registered to the X-ray CT image, and the accuracy of each registration was compared. In the studies of PET-CT registration, the transmission images and X-ray CT images were registered at first, because the 11 C-methionine PET images bear little resemblance to the underlying anatomical images. Next, the emission images were realigned by using the same registration parameters. The X-ray CT images obtained from a single subject at the different time were registered to the first X-ray CT images, respectively. Results: In the SPECT-CT registration, the blood pool-CT registration is the best among three SPECT images in visual inspection by radiologists. In the PET-CT registration, the Transmission-CT registrations got good results. Therefore, Emission-CT registrations also got good results. In the CT-CT registration, the X-ray CT images obtained from a single subject at the different time were superimposed well each other except for lower lobe. As the results, it was

Imaging corn plants with PhytoPET, a modular PET system for plant biology

Energy Technology Data Exchange (ETDEWEB)

Lee, S.; Kross, B.; McKisson, J.; McKisson, J. E.; Weisenberger, A. G.; Xi, W.; Zorn, C.; Bonito, G.; Howell, C. R.; Reid, C. D.; Crowell, A.; Cumberbatch, L. C.; Topp, C.; Smith, M. F.

2013-11-01

PhytoPET is a modular positron emission tomography (PET) system designed specifically for plant imaging. The PhytoPET design allows flexible arrangements of PET detectors based on individual standalone detector modules built from single Hamamatsu H8500 position sensitive photomultiplier tubes and pixelated LYSO arrays. We have used the PhytoPET system to perform preliminary corn plant imaging studies at the Duke University Biology Department Phytotron. Initial evaluation of the PhytoPET system to image the biodistribution of the positron emitting tracer {sup 11}C in corn plants is presented. {sup 11}CO{sub 2} is loaded into corn seedlings by a leaf-labeling cuvette and translocation of {sup 11}C-sugars is imaged by a flexible arrangement of PhytoPET modules on each side. The PhytoPET system successfully images {sup 11}C within corn plants and allows for the dynamic measurement of {sup 11}C-sugar translocation from the leaf to the roots.

Repurposing the Microsoft Kinect for Windows v2 for external head motion tracking for brain PET

International Nuclear Information System (INIS)

Noonan, P J; Gunn, R N; Howard, J; Hallett, W A

2015-01-01

Medical imaging systems such as those used in positron emission tomography (PET) are capable of spatial resolutions that enable the imaging of small, functionally important brain structures. However, the quality of data from PET brain studies is often limited by subject motion during acquisition. This is particularly challenging for patients with neurological disorders or with dynamic research studies that can last 90 min or more. Restraining head movement during the scan does not eliminate motion entirely and can be unpleasant for the subject. Head motion can be detected and measured using a variety of techniques that either use the PET data itself or an external tracking system. Advances in computer vision arising from the video gaming industry could offer significant benefits when re-purposed for medical applications. A method for measuring rigid body type head motion using the Microsoft Kinect v2 is described with results presenting  ⩽0.5 mm spatial accuracy. Motion data is measured in real-time at 30 Hz using the KinectFusion algorithm. Non-rigid motion is detected using the residual alignment energy data of the KinectFusion algorithm allowing for unreliable motion to be discarded. Motion data is aligned to PET listmode data using injected pulse sequences into the PET/CT gantry allowing for correction of rigid body motion. Pilot data from a clinical dynamic PET/CT examination is shown. (paper)

Repurposing the Microsoft Kinect for Windows v2 for external head motion tracking for brain PET

Science.gov (United States)

Noonan, P. J.; Howard, J.; Hallett, W. A.; Gunn, R. N.

2015-11-01

Medical imaging systems such as those used in positron emission tomography (PET) are capable of spatial resolutions that enable the imaging of small, functionally important brain structures. However, the quality of data from PET brain studies is often limited by subject motion during acquisition. This is particularly challenging for patients with neurological disorders or with dynamic research studies that can last 90 min or more. Restraining head movement during the scan does not eliminate motion entirely and can be unpleasant for the subject. Head motion can be detected and measured using a variety of techniques that either use the PET data itself or an external tracking system. Advances in computer vision arising from the video gaming industry could offer significant benefits when re-purposed for medical applications. A method for measuring rigid body type head motion using the Microsoft Kinect v2 is described with results presenting  ⩽0.5 mm spatial accuracy. Motion data is measured in real-time at 30 Hz using the KinectFusion algorithm. Non-rigid motion is detected using the residual alignment energy data of the KinectFusion algorithm allowing for unreliable motion to be discarded. Motion data is aligned to PET listmode data using injected pulse sequences into the PET/CT gantry allowing for correction of rigid body motion. Pilot data from a clinical dynamic PET/CT examination is shown.

Computer simulations suggest that acute correction of hyperglycaemia with an insulin bolus protocol might be useful in brain FDG PET

Energy Technology Data Exchange (ETDEWEB)

Buchert, R.; Brenner, W.; Apostolova, I.; Mester, J.; Clausen, M. [University Medical Center Hamburg-Eppendorf (Germany). Dept. of Nuclear Medicine; Santer, R. [University Medical Center Hamburg-Eppendorf (Germany). Center for Gynaecology, Obstetrics and Paediatrics; Silverman, D.H.S. [David Geffen School of Medicine at UCLA, Los Angeles, CA (United States). Dept. of Molecular and Medical Pharmacology

2009-07-01

FDG PET in hyperglycaemic subjects often suffers from limited statistical image quality, which may hamper visual and quantitative evaluation. In our study the following insulin bolus protocol is proposed for acute correction of hyperglycaemia (> 7.0 mmol/l) in brain FDG PET. (i) Intravenous bolus injection of short-acting insulin, one I.E. for each 0.6 mmol/l blood glucose above 7.0. (ii) If 20 min after insulin administration plasma glucose is {<=} 7.0 mmol/l, proceed to (iii). If insulin has not taken sufficient effect step back to (i). Compute insulin dose with the updated blood glucose level. (iii) Wait further 20 min before injection of FDG. (iv) Continuous supervision of the patient during the whole scanning procedure. The potential of this protocol for improvement of image quality in brain FDG PET in hyperglycaemic subjects was evaluated by computer simulations within the Sokoloff model. A plausibility check of the prediction of the computer simulations on the magnitude of the effect that might be achieved by correction of hyperglycaemia was performed by retrospective evaluation of the relation between blood glucose level and brain FDG uptake in 89 subjects in whom FDG PET had been performed for diagnosis of Alzheimer's disease. The computer simulations suggested that acute correction of hyperglycaemia according to the proposed bolus insulin protocol might increase the FDG uptake of the brain by up to 80%. The magnitude of this effect was confirmed by the patient data. The proposed management protocol for acute correction of hyperglycaemia with insulin has the potential to significantly improve the statistical quality of brain FDG PET images. This should be confirmed in a prospective study in patients. (orig.)

Computer simulations suggest that acute correction of hyperglycaemia with an insulin bolus protocol might be useful in brain FDG PET

International Nuclear Information System (INIS)

Buchert, R.; Brenner, W.; Apostolova, I.; Mester, J.; Clausen, M.; Santer, R.; Silverman, D.H.S.

2009-01-01

FDG PET in hyperglycaemic subjects often suffers from limited statistical image quality, which may hamper visual and quantitative evaluation. In our study the following insulin bolus protocol is proposed for acute correction of hyperglycaemia (> 7.0 mmol/l) in brain FDG PET. (i) Intravenous bolus injection of short-acting insulin, one I.E. for each 0.6 mmol/l blood glucose above 7.0. (ii) If 20 min after insulin administration plasma glucose is ≤ 7.0 mmol/l, proceed to (iii). If insulin has not taken sufficient effect step back to (i). Compute insulin dose with the updated blood glucose level. (iii) Wait further 20 min before injection of FDG. (iv) Continuous supervision of the patient during the whole scanning procedure. The potential of this protocol for improvement of image quality in brain FDG PET in hyperglycaemic subjects was evaluated by computer simulations within the Sokoloff model. A plausibility check of the prediction of the computer simulations on the magnitude of the effect that might be achieved by correction of hyperglycaemia was performed by retrospective evaluation of the relation between blood glucose level and brain FDG uptake in 89 subjects in whom FDG PET had been performed for diagnosis of Alzheimer's disease. The computer simulations suggested that acute correction of hyperglycaemia according to the proposed bolus insulin protocol might increase the FDG uptake of the brain by up to 80%. The magnitude of this effect was confirmed by the patient data. The proposed management protocol for acute correction of hyperglycaemia with insulin has the potential to significantly improve the statistical quality of brain FDG PET images. This should be confirmed in a prospective study in patients. (orig.)

High resolution reconstruction of PET images using the iterative OSEM algorithm

International Nuclear Information System (INIS)

Doll, J.; Bublitz, O.; Werling, A.; Haberkorn, U.; Semmler, W.; Adam, L.E.; Pennsylvania Univ., Philadelphia, PA; Brix, G.

2004-01-01

Aim: Improvement of the spatial resolution in positron emission tomography (PET) by incorporation of the image-forming characteristics of the scanner into the process of iterative image reconstruction. Methods: All measurements were performed at the whole-body PET system ECAT EXACT HR + in 3D mode. The acquired 3D sinograms were sorted into 2D sinograms by means of the Fourier rebinning (FORE) algorithm, which allows the usage of 2D algorithms for image reconstruction. The scanner characteristics were described by a spatially variant line-spread function (LSF), which was determined from activated copper-64 line sources. This information was used to model the physical degradation processes in PET measurements during the course of 2D image reconstruction with the iterative OSEM algorithm. To assess the performance of the high-resolution OSEM algorithm, phantom measurements performed at a cylinder phantom, the hotspot Jaszczack phantom, and the 3D Hoffmann brain phantom as well as different patient examinations were analyzed. Results: Scanner characteristics could be described by a Gaussian-shaped LSF with a full-width at half-maximum increasing from 4.8 mm at the center to 5.5 mm at a radial distance of 10.5 cm. Incorporation of the LSF into the iteration formula resulted in a markedly improved resolution of 3.0 and 3.5 mm, respectively. The evaluation of phantom and patient studies showed that the high-resolution OSEM algorithm not only lead to a better contrast resolution in the reconstructed activity distributions but also to an improved accuracy in the quantification of activity concentrations in small structures without leading to an amplification of image noise or even the occurrence of image artifacts. Conclusion: The spatial and contrast resolution of PET scans can markedly be improved by the presented image restauration algorithm, which is of special interest for the examination of both patients with brain disorders and small animals. (orig.)

[11C]CHIBA-1001 as a novel PET ligand for alpha7 nicotinic receptors in the brain: a PET study in conscious monkeys.

Directory of Open Access Journals (Sweden)

Kenji Hashimoto

Full Text Available BACKGROUND: The alpha7 nicotinic acetylcholine receptors (nAChRs play an important role in the pathophysiology of neuropsychiatric diseases such as schizophrenia and Alzheimer's disease. However, there are currently no suitable positron emission tomography (PET radioligands for imaging alpha7 nAChRs in the intact human brain. Here we report the novel PET radioligand [11C]CHIBA-1001 for in vivo imaging of alpha7 nAChRs in the non-human primate brain. METHODOLOGY/PRINCIPAL FINDINGS: A receptor binding assay showed that CHIBA-1001 was a highly selective ligand at alpha7 nAChRs. Using conscious monkeys, we found that the distribution of radioactivity in the monkey brain after intravenous administration of [11C]CHIBA-1001 was consistent with the regional distribution of alpha7 nAChRs in the monkey brain. The distribution of radioactivity in the brain regions after intravenous administration of [11C]CHIBA-1001 was blocked by pretreatment with the selective alpha7 nAChR agonist SSR180711 (5.0 mg/kg. However, the distribution of [11C]CHIBA-1001 was not altered by pretreatment with the selective alpha4beta2 nAChR agonist A85380 (1.0 mg/kg. Interestingly, the binding of [11C]CHIBA-1001 in the frontal cortex of the monkey brain was significantly decreased by subchronic administration of the N-methyl-D-aspartate (NMDA receptor antagonist phencyclidine (0.3 mg/kg, twice a day for 13 days; which is a non-human primate model of schizophrenia. CONCLUSIONS/SIGNIFICANCE: The present findings suggest that [11C]CHIBA-1001 could be a novel useful PET ligand for in vivo study of the receptor occupancy and pathophysiology of alpha7 nAChRs in the intact brain of patients with neuropsychiatric diseases such as schizophrenia and Alzheimer's disease.

Statistical parametric maps of 18F-FDG PET and 3-D autoradiography in the rat brain: a cross-validation study

International Nuclear Information System (INIS)

Prieto, Elena; Marti-Climent, Josep M.; Collantes, Maria; Molinet, Francisco; Delgado, Mercedes; Garcia-Garcia, Luis; Pozo, Miguel A.; Juri, Carlos; Fernandez-Valle, Maria E.; Gago, Belen; Obeso, Jose A.; Penuelas, Ivan

2011-01-01

Although specific positron emission tomography (PET) scanners have been developed for small animals, spatial resolution remains one of the most critical technical limitations, particularly in the evaluation of the rodent brain. The purpose of the present study was to examine the reliability of voxel-based statistical analysis (Statistical Parametric Mapping, SPM) applied to 18 F-fluorodeoxyglucose (FDG) PET images of the rat brain, acquired on a small animal PET not specifically designed for rodents. The gold standard for the validation of the PET results was the autoradiography of the same animals acquired under the same physiological conditions, reconstructed as a 3-D volume and analysed using SPM. Eleven rats were studied under two different conditions: conscious or under inhalatory anaesthesia during 18 F-FDG uptake. All animals were studied in vivo under both conditions in a dedicated small animal Philips MOSAIC PET scanner and magnetic resonance images were obtained for subsequent spatial processing. Then, rats were randomly assigned to a conscious or anaesthetized group for postmortem autoradiography, and slices from each animal were aligned and stacked to create a 3-D autoradiographic volume. Finally, differences in 18 F-FDG uptake between conscious and anaesthetized states were assessed from PET and autoradiography data by SPM analysis and results were compared. SPM results of PET and 3-D autoradiography are in good agreement and led to the detection of consistent cortical differences between the conscious and anaesthetized groups, particularly in the bilateral somatosensory cortices. However, SPM analysis of 3-D autoradiography also highlighted differences in the thalamus that were not detected with PET. This study demonstrates that any difference detected with SPM analysis of MOSAIC PET images of rat brain is detected also by the gold standard autoradiographic technique, confirming that this methodology provides reliable results, although partial volume

Classification of Parkinsonian syndromes from FDG-PET brain data using decision trees with SSM/PCA features.

Science.gov (United States)

Mudali, D; Teune, L K; Renken, R J; Leenders, K L; Roerdink, J B T M

2015-01-01

Medical imaging techniques like fluorodeoxyglucose positron emission tomography (FDG-PET) have been used to aid in the differential diagnosis of neurodegenerative brain diseases. In this study, the objective is to classify FDG-PET brain scans of subjects with Parkinsonian syndromes (Parkinson's disease, multiple system atrophy, and progressive supranuclear palsy) compared to healthy controls. The scaled subprofile model/principal component analysis (SSM/PCA) method was applied to FDG-PET brain image data to obtain covariance patterns and corresponding subject scores. The latter were used as features for supervised classification by the C4.5 decision tree method. Leave-one-out cross validation was applied to determine classifier performance. We carried out a comparison with other types of classifiers. The big advantage of decision tree classification is that the results are easy to understand by humans. A visual representation of decision trees strongly supports the interpretation process, which is very important in the context of medical diagnosis. Further improvements are suggested based on enlarging the number of the training data, enhancing the decision tree method by bagging, and adding additional features based on (f)MRI data.

FDG-PET/CT Brain Findings in a Patient With Macrophagic Myofasciitis

OpenAIRE

Van Der Gucht, Axel; Aoun-Sebaiti, Mehdi; Kauv, Paul; Guedj, Eric; Aouizerate, Jessie; Verger, Antoine; Gherardi, Romain K.; Bachoud-Levi, Anne-Catherine; Authier, Fran?ois-J?r?me; Itti, Emmanuel

2015-01-01

Brain Positron Emission Tomography/Computed Tomography with 18F-fluorodeoxyglucose (FDG PET/CT) was performed in a 44-year-old woman with marked cognitive impairment, diffuse myalgias, sensory, memory and visual disorders, and chronic fatigue, presenting with histopathological features of macrophagic myofasciitis (MMF) at deltoid muscle biopsy. Cerebromedullary Magnetic Resonance Imaging (MRI), electromyography, ophthalmic examination, and cerebrospinal fluid analysis were normal. Visual anal...

Brain-Only Metastases Seen on FDG PET as First Relapse of Papillary Thyroid Carcinoma Two Years Post-Thyroidectomy.

Science.gov (United States)

Naddaf, Sleiman Y; Syed, Ghulam Mustafa Shah; Hadb, Abdulrahman; Al-Thaqfi, Saif

2016-09-01

We report a case of a 60-year-old man diagnosed with papillary thyroid cancer who had a relapse seen only in the brain at FDG PET on standard images. Total thyroidectomy was performed in July 2013 after initial diagnosis. Patient received I ablation in December 2013, followed by external beam radiotherapy to the neck. In September 2015, the patient presented with neurological symptoms. Brain MRI showed multiple brain metastases later confirmed on histopathology. An FDG PET/CT scan was performed to evaluate the whole body in November 2015. Multiple hypermetabolic lesions were identified in the brain with no other lesion up to mid thighs.

64Cu-DOTA-trastuzumab PET imaging in patients with HER2-positive breast cancer.

Science.gov (United States)

Tamura, Kenji; Kurihara, Hiroaki; Yonemori, Kan; Tsuda, Hitoshi; Suzuki, Junko; Kono, Yuzuru; Honda, Natsuki; Kodaira, Makoto; Yamamoto, Harukaze; Yunokawa, Mayu; Shimizu, Chikako; Hasegawa, Koki; Kanayama, Yousuke; Nozaki, Satoshi; Kinoshita, Takayuki; Wada, Yasuhiro; Tazawa, Shusaku; Takahashi, Kazuhiro; Watanabe, Yasuyoshi; Fujiwara, Yasuhiro

2013-11-01

The purpose of this study was to determine the safety, distribution, internal dosimetry, and initial human epidermal growth factor receptor 2 (HER2)-positive tumor images of (64)Cu-DOTA-trastuzumab in humans. PET was performed on 6 patients with primary or metastatic HER2-positive breast cancer at 1, 24, and 48 h after injection of approximately 130 MBq of the probe (64)Cu-DOTA-trastuzumab. Radioactivity data were collected from the blood, urine, and normal-tissue samples of these 6 patients, and the multiorgan biodistribution and internal dosimetry of the probe were evaluated. Safety data were collected for all the patients after the administration of (64)Cu-DOTA-trastuzumab and during the 1-wk follow-up period. According to our results, the best timing for the assessment of (64)Cu-DOTA-trastuzumab uptake by the tumor was 48 h after injection. Radiation exposure during (64)Cu-DOTA-trastuzumab PET was equivalent to that during conventional (18)F-FDG PET. The radioactivity in the blood was high, but uptake of (64)Cu-DOTA-trastuzumab in normal tissues was low. In 2 patients, (64)Cu-DOTA-trastuzumab PET showed brain metastases, indicative of blood-brain barrier disruptions. In 3 patients, (64)Cu-DOTA-trastuzumab PET imaging also revealed primary breast tumors at the lesion sites initially identified by CT. The findings of this study indicated that (64)Cu-DOTA-trastuzumab PET is feasible for the identification of HER2-positive lesions in patients with primary and metastatic breast cancer. The dosimetry and pharmacologic safety results were acceptable at the dose required for adequate PET imaging.

18F-Alfatide II PET/CT in healthy human volunteers and patients with brain metastases

International Nuclear Information System (INIS)

Yu, Chunjing; Mi, Baoming; Wan, Weixing; Pan, Donghui; Xu, Yuping; Yang, Min; Lang, Lixin; Niu, Gang; Chen, Xiaoyuan

2015-01-01

We report the biodistribution and radiation dosimetry of an integrin α v β 3 specific PET tracer 18 F-AlF-NOTA-E[PEG 4 -c(RGDfk)] 2 (denoted as 18 F-Alfatide II). We also assessed the value of 18 F-Alfatide II in patients with brain metastases. A series of torso (from the skull to the thigh) static images were acquired in five healthy volunteers (3 M, 2 F) at 5, 10, 15, 30, 45, and 60 min after injection of 18 F-Alfatide II (257 ± 48 MBq). Regions of interest (ROIs) were drawn manually, and the time-activity curves (TACs) were obtained for major organs. Nine patients with brain metastases were examined by static PET imaging with 18 F-FDG (5.55 MBq/kg) and 18 F-Alfatide II. Injection of 18 F-Alfatide II was well tolerated in all healthy volunteers, with no serious tracer-related adverse events found. 18 F-Alfatide II showed rapid clearance from the blood pool and kidneys. The total effective dose equivalent (EDE) and effective dose (ED) were 0.0277 ± 0.003 mSv/MBq and 0.0198 ± 0.002 mSv/MBq, respectively. The organs with the highest absorbed dose were the kidneys and the spleen. Nine patients with 20 brain metastatic lesions identified by MRI and/or CT were enrolled in this study. All 20 brain lesions were visualized by 18 F-Alfatide II PET, while only ten lesions were visualized by 18 F-FDG, and 13 by CT. F-Alfatide II is a safe PET tracer with a favorable dosimetry profile. The observed ED suggests that 18 F-Alfatide II is feasible for human studies. 18 F-Alfatide II has potential value in finding brain metastases of different cancers as a biomarker of angiogenesis. (orig.)

Statistical probabilistic mapping in the individual brain space: decreased metabolism in epilepsy with FDG PET

International Nuclear Information System (INIS)

Oh, Jung Su; Lee, Jae Sung; Kim, Yu Kyeong; Chung, June Key; Lee, Myung Chul; Lee, Dong Soo

2005-01-01

In the statistical probabilistic mapping, commonly, differences between two or more groups of subjects are statistically analyzed following spatial normalization. However, to our best knowledge, there is few study which performed the statistical mapping in the individual brain space rather than in the stereotaxic brain space, i.e., template space. Therefore, in the current study, a new method for mapping the statistical results in the template space onto individual brain space has been developed. Four young subjects with epilepsy and their age-matched thirty normal healthy subjects were recruited. Both FDG PET and T1 structural MRI was scanned in these groups. Statistical analysis on the decreased FDG metabolism in epilepsy was performed on the SPM with two sample t-test (p < 0.001, intensity threshold 100). To map the statistical results onto individual space, inverse deformation was performed as follows. With SPM deformation toolbox, DCT (discrete cosine transform) basis-encoded deformation fields between individual T1 images and T1 MNI template were obtained. Afterward, inverse of those fields, i.e., inverse deformation fields were obtained. Since both PET and T1 images have been already normalized in the same MNI space, inversely deformed results in PET is on the individual brain MRI space. By applying inverse deformation field on the statistical results of the PET, the statistical map of decreased metabolism in individual spaces were obtained. With statistical results in the template space, localization of decreased metabolism was in the inferior temporal lobe, which was slightly inferior to the hippocampus. The statistical results in the individual space were commonly located in the hippocampus, where the activation should be decreased according to a priori knowledge of neuroscience. With our newly developed statistical mapping on the individual spaces, the localization of the brain functional mapping became more appropriate in the sense of neuroscience

Statistical probabilistic mapping in the individual brain space: decreased metabolism in epilepsy with FDG PET

Energy Technology Data Exchange (ETDEWEB)

Oh, Jung Su; Lee, Jae Sung; Kim, Yu Kyeong; Chung, June Key; Lee, Myung Chul; Lee, Dong Soo [Seoul National University Hospital, Seoul (Korea, Republic of)

2005-07-01

In the statistical probabilistic mapping, commonly, differences between two or more groups of subjects are statistically analyzed following spatial normalization. However, to our best knowledge, there is few study which performed the statistical mapping in the individual brain space rather than in the stereotaxic brain space, i.e., template space. Therefore, in the current study, a new method for mapping the statistical results in the template space onto individual brain space has been developed. Four young subjects with epilepsy and their age-matched thirty normal healthy subjects were recruited. Both FDG PET and T1 structural MRI was scanned in these groups. Statistical analysis on the decreased FDG metabolism in epilepsy was performed on the SPM with two sample t-test (p < 0.001, intensity threshold 100). To map the statistical results onto individual space, inverse deformation was performed as follows. With SPM deformation toolbox, DCT (discrete cosine transform) basis-encoded deformation fields between individual T1 images and T1 MNI template were obtained. Afterward, inverse of those fields, i.e., inverse deformation fields were obtained. Since both PET and T1 images have been already normalized in the same MNI space, inversely deformed results in PET is on the individual brain MRI space. By applying inverse deformation field on the statistical results of the PET, the statistical map of decreased metabolism in individual spaces were obtained. With statistical results in the template space, localization of decreased metabolism was in the inferior temporal lobe, which was slightly inferior to the hippocampus. The statistical results in the individual space were commonly located in the hippocampus, where the activation should be decreased according to a priori knowledge of neuroscience. With our newly developed statistical mapping on the individual spaces, the localization of the brain functional mapping became more appropriate in the sense of neuroscience.

Lesions inflammatory activity quantification in multiple sclerosis using [{sup 11}C]-(R)-PK11195 PET brain images; Quantificacao da atividade inflamatoria em lesoes na esclerose multipla usando imagens PET cerebrais com [{sup 11}C]-(R)-PK11195

Energy Technology Data Exchange (ETDEWEB)

Schuck, Phelipi N.; Narciso, Lucas D.L.; Dartora, Caroline M.; Silva, Ana M. Marques da, E-mail: phelipi.schuck@acad.pucrs.br [Pontificia Universidade Catolica do Rio Grande do Sul (PUC-RS), Porto Alegre, RS (Brazil). Nucleo de Pesquisa em Imagens Medicas

2016-07-01

The criteria for multiple sclerosis (MS) diagnosis include the presence of lesions in brain regions called black holes (BH), characterized by low signal on magnetic resonance imaging T1-weighted. Studies suggest that lesions in MS, if there is an inflammatory process, can be detected in PET imaging with [{sup 11}C]- (R)-PK11195. The aim of this study is to investigate the uptake of [{sup 11}C]-(R)-PK11195 in BH in PET images, searching for inflammation activity in lesions and neighborhoods. Semiquantitative methods of SUV and uptake normalization were applied to PET images, in different time intervals, acquired from 8 MS patients and 5 healthy controls. Higher uptake was identified in BH and its edges, when compared with health controls white matter, when the SUV method is applied (p < 0,01, 40 to 60 min). When uptake normalization method is applied, smaller uptake in black holes and its your edges is observed, when compared with white matter apparently healthy (p < 0,01, 0 to 60 min). (author)

SPECT and PET imaging in epilepsy

International Nuclear Information System (INIS)

Semah, F.

2007-01-01

Positron emission tomography (PET) and single photon emission computed tomography (SPECT) imaging are very useful for the management of patients with medically refractory partial epilepsy. Presurgical evaluation of patients with medically refractory partial epilepsy often included PET imaging using FDG. The use of SPECT in these patients adds some more information and gives the clinicians the possibility of having ictal imaging. Furthermore, PET and SPECT imaging are performed to better understand the pathophysiology of epilepsy. (authors)

Clinical PET/CT imaging. Promises and misconceptions

International Nuclear Information System (INIS)

Czernin, J.; Auerbach, M.A.

2005-01-01

PET/CT is now established as the most important imaging tool in oncology. PET/CT stages and restages cancer with a higher accuracy than PET or CT alone. The sometimes irrational approach to combine state of the art PET with the highest end CT devices should give way to a more reasonable equipment design tailored towards the specific clinical indications in well-defined patient populations. The continuing success of molecular PET/CT now depends more upon advances in molecular imaging with the introduction of targeted imaging probes for individualized therapy approaches in cancer patients and less upon technological advances of imaging equipment. (orig.)

Brain dopaminergic systems : imaging with positron tomography

Energy Technology Data Exchange (ETDEWEB)

Baron, J C [University of Caen/INSERM U, Caen (France). CYCERON; Comar, D [E.E.C. Concerted Action on P.E.T. Investigations of Cellular Regeneration and Degeneration, Orsay (France) CEA, 91 - Orsay (France). Service Hospitalier Frederic Joliot; Farde, L [Karolinska Sjukhuset, Stockholm (Sweden); Martinot, J L; Mazoyer, B [CEA, 91 - Orsay (France). Service Hospitalier Frederic Joliot Paris-

1991-01-01

Imaging of the dopaminergic system in the human brain with the in vivo use of Positron Emission Tomography emerged in the late 1980s as a tool of major importance in clinical neurosciences and pharmacology. The last few years have witnessed rapid development of new radiotracers specific to receptors, reuptake sites and enzymes of the dopamine system; the application of these radiotracers has led to major break-troughs in the pathophysiology and therapy of movement disorders and schizophrenic-like psychoses. This book is the first to collect, in a single volume, state-of-the-art contributions to the various aspects of this research. Its contents address methodological issues related to the design, labelling, quantitative imaging and compartmental modeli-sation of radioligands of the post-synaptic, pre-synaptic and enzyme sites of the dopamine system and to their use in clinical research in the fields of Parkinson's disease as well as other movement disorders, psychoses and neuroleptic receptor occupancy. The chapters were written by leading European scientists in the field of PET, gathered together in Caen (France, November 1990) under the aegis of the EEC Concerted Action on PET Investigations of Cellular Regeneration and Degeneration. This book provides a current and comprehensive overview on PET studies of the brain dopamine system which should aid and interest neurologists , psychiatrists, pharmacologists and medical imaging scientists. (author). refs.; figs.; tabs.

FDG-PET on Irradiated Brain Tumor: Ten Years' Summary

International Nuclear Information System (INIS)

Wang, S.X.; Boethius, J.; Ericson, K.

2006-01-01

Purpose: To evaluate FDG-PET in post-radiotherapy differentiation of tumor recurrence/malignant degeneration and radiation reaction, and to assess the role of PET in terms of survival. Material and Methods: 117 consecutive patients with a total of 156 FDG-PET examinations with positive but non-diagnostic MRI and/or CT were included. Final diagnosis was based on histopathology or correlated with radiologic and clinical follow-up. Brain metastases from lung carcinomas were further studied separately. Survival time was analysed using the Kaplan-Meier method. Results: There were 61 true-positive, 2 false-positive, 15 false-negative, and 51 true-negative PET examinations; 5 positive and 22 negative PET examinations were indeterminate. The positive predictive value of a PET examination was 96% in all and 100% in brain metastases from lung carcinoma. The negative predictive value based on the histopathologic results was 55.6%. Survival time was significantly longer in patients with negative PET. Conclusion: FDG-PET is a valuable tool in the detection of tumor recurrence, especially lung carcinoma metastasis. FDG uptake is a prognostic marker

Simultaneous PET/MRI with 13C magnetic resonance spectroscopic imaging (hyperPET): phantom-based evaluation of PET quantification

DEFF Research Database (Denmark)

Hansen, Adam E.; Andersen, Flemming L.; Henriksen, Sarah T.

2016-01-01

Background: Integrated PET/MRI with hyperpolarized 13C magnetic resonance spectroscopic imaging (13C-MRSI) offers simultaneous, dual-modality metabolic imaging. A prerequisite for the use of simultaneous imaging is the absence of interference between the two modalities. This has been documented...... for a clinical whole-body system using simultaneous 1 H-MRI and PET but never for 13C-MRSI and PET. Here, the feasibility of simultaneous PET and 13C-MRSI as well as hyperpolarized 13C-MRSI in an integrated whole-body PET/MRI hybrid scanner is evaluated using phantom experiments. Methods: Combined PET and 13C......-MRSI phantoms including a NEMA [18F]-FDG phantom, 13C-acetate and 13C-urea sources, and hyperpolarized 13C-pyruvate were imaged repeatedly with PET and/or 13C-MRSI. Measurements evaluated for interference effects included PET activity values in the largest sphere and a background region; total number of PET...

Direct reconstruction of parametric images for brain PET with event-by-event motion correction: evaluation in two tracers across count levels

Science.gov (United States)

Germino, Mary; Gallezot, Jean-Dominque; Yan, Jianhua; Carson, Richard E.

2017-07-01

Parametric images for dynamic positron emission tomography (PET) are typically generated by an indirect method, i.e. reconstructing a time series of emission images, then fitting a kinetic model to each voxel time activity curve. Alternatively, ‘direct reconstruction’, incorporates the kinetic model into the reconstruction algorithm itself, directly producing parametric images from projection data. Direct reconstruction has been shown to achieve parametric images with lower standard error than the indirect method. Here, we present direct reconstruction for brain PET using event-by-event motion correction of list-mode data, applied to two tracers. Event-by-event motion correction was implemented for direct reconstruction in the Parametric Motion-compensation OSEM List-mode Algorithm for Resolution-recovery reconstruction. The direct implementation was tested on simulated and human datasets with tracers [11C]AFM (serotonin transporter) and [11C]UCB-J (synaptic density), which follow the 1-tissue compartment model. Rigid head motion was tracked with the Vicra system. Parametric images of K 1 and distribution volume (V T  =  K 1/k 2) were compared to those generated by the indirect method by regional coefficient of variation (CoV). Performance across count levels was assessed using sub-sampled datasets. For simulated and real datasets at high counts, the two methods estimated K 1 and V T with comparable accuracy. At lower count levels, the direct method was substantially more robust to outliers than the indirect method. Compared to the indirect method, direct reconstruction reduced regional K 1 CoV by 35-48% (simulated dataset), 39-43% ([11C]AFM dataset) and 30-36% ([11C]UCB-J dataset) across count levels (averaged over regions at matched iteration); V T CoV was reduced by 51-58%, 54-60% and 30-46%, respectively. Motion correction played an important role in the dataset with larger motion: correction increased regional V T by 51% on average in the [11C

A useful PET probe [11C]BU99008 with ultra-high specific radioactivity for small animal PET imaging of I2-imidazoline receptors in the hypothalamus

International Nuclear Information System (INIS)

Kawamura, Kazunori; Shimoda, Yoko; Yui, Joji; Zhang, Yiding; Yamasaki, Tomoteru; Wakizaka, Hidekatsu; Hatori, Akiko; Xie, Lin; Kumata, Katsushi; Fujinaga, Masayuki; Ogawa, Masanao; Kurihara, Yusuke; Nengaki, Nobuki; Zhang, Ming-Rong

2017-01-01

Introduction: A positron emission tomography (PET) probe with ultra-high specific radioactivity (SA) enables measuring high receptor specific binding in brain regions by avoiding mass effect of the PET probe itself. It has been reported that PET probe with ultra-high SA can detect small change caused by endogenous or exogenous ligand. Recently, Kealey et al. developed [ 11 C]BU99008, a more potent PET probe for I 2 -imidazoline receptors (I 2 Rs) imaging, with a conventional SA (mean 76 GBq/μmol) showed higher specific binding in the brain. Here, to detect small change of specific binding for I 2 Rs caused by endogenous or exogenous ligand in an extremely small region, such as hypothalamus in the brain, we synthesized and evaluated [ 11 C]BU99008 with ultra-high SA as a useful PET probe for small-animal PET imaging of I 2 Rs. Methods: [ 11 C]BU99008 was prepared by [ 11 C]methylation of N-desmethyl precursor with [ 11 C]methyl iodide. Biodistribution, metabolite analysis, and brain PET studies were conducted in rats. Results: [ 11 C]BU99008 with ultra-high SA in the range of 5400–16,600 GBq/μmol were successfully synthesized (n = 7), and had appropriate radioactivity for in vivo study. In the biodistribution study, the mean radioactivity levels in all investigated tissues except for the kidney did not show significant difference between [ 11 C]BU99008 with ultra-high SA and that with conventional SA. In the metabolite analysis, the percentage of unchanged [ 11 C]BU99008 at 30 min after the injection of probes with ultra-high and conventional SA was similar in rat brain and plasma. In the PET study of rats' brain, radioactivity level (AUC 30–60 min ) in the hypothalamus of rats injected with [ 11 C]BU99008 with ultra-high SA (64 [SUV ∙ min]) was significantly higher than that observed for that with conventional SA (50 [SUV ∙ min]). The specific binding of [ 11 C]BU99008 with ultra-high SA (86% of total binding) for I 2 R was higher than that of

PET imaging of brain with the β-amyloid probe, [11C]6-OH-BTA-1, in a transgenic mouse model of Alzheimer's disease

International Nuclear Information System (INIS)

Toyama, Hiroshi; Ye, Daniel; Cohen, Robert M.; Ichise, Masanori; Liow, Jeih-San; Cai, Lisheng; Musachio, John L.; Hong, Jinsoo; Crescenzo, Mathew; Tipre, Dnyanesh; Lu, Jian-Qiang; Zoghbi, Sami; Vines, Douglass C.; Pike, Victor W.; Innis, Robert B.; Jacobowitz, David; Seidel, Jurgen; Green, Michael V.; Katada, Kazuhiro

2005-01-01

The purpose of this study was to evaluate the capacity of [ 11 C]6-OH-BTA-1 and positron emission tomography (PET) to quantify β-amyloid (Aβ) plaques in the Tg2576 mouse model of Alzheimer's disease (AD). PET imaging was performed with the NIH ATLAS small animal scanner in six elderly transgenic mice (Tg2576; age 22.0±1.8 months; 23.6±2.6 g) overexpressing a mutated form of human β-amyloid precursor protein (APP) known to result in the production of Aβ plaques, and in six elderly wild-type litter mates (age 21.8±1.6 months; 29.5±4.7 g). Dynamic PET scans were performed for 30 min in each mouse under 1% isoflurane inhalation anesthesia after a bolus injection of 13-46 MBq of [ 11 C]6-OH-BTA-1. PET data were reconstructed with 3D OSEM. On the coronal PET image, irregular regions of interest (ROIs) were placed on frontal cortex (FR), parietal cortex (PA), striatum (ST), thalamus (TH), pons (PO), and cerebellum (CE), guided by a mouse stereotaxic atlas. Time-activity curves (TACs) (expressed as percent injected dose per gram normalized to body weight: % ID-kg/g) were obtained for FR, PA, ST, TH, PO, and CE. ROI-to-CE radioactivity ratios were also calculated. Following PET scans, sections of mouse brain prepared from anesthetized and fixative-perfused mice were stained with thioflavin-S. TACs for [ 11 C]6-OH-BTA-1 in all ROIs peaked early (at 30-55 s), with radioactivity washing out quickly thereafter in both transgenic and wild-type mice. Peak uptake in all regions was significantly lower in transgenic mice than in wild-type mice. During the later part of the washout phase (12-30 min), the mean FR/CE and PA/CE ratios were higher in transgenic than in wild-type mice (1.06±0.04 vs 0.98±0.07, p=0.04; 1.06±0.09 vs 0.93±0.08 p=0.02) while ST/CE, TH/CE, and PO/CE ratios were not. Ex vivo staining revealed widespread Aβ plaques in cortex, but not in cerebellum of transgenic mice or in any brain regions of wild-type mice. Marked reductions in brain uptake of this

Experience of Dual Time Point Brain F-18 FDG PET/CT Imaging in Patients with Infections Disease

Energy Technology Data Exchange (ETDEWEB)

Kim, Dae Weung; Kim, Chang Guhn; Park, Soon Ah; Jung, Sang Ah [Wonkwang University School of Medicine, Iksan (Korea, Republic of)

2010-06-15

Dual time point FDG PET imaging (DTPI) has been considered helpful for discrimination of benign and malignant disease, and staging lymph node status in patients with pulmonary malignancy. However, DTPI for benign disease has been rarely reported, and it may show a better description of metabolic status and extent of benign infection disease than early imaging only. The authors report on the use F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) imaging with additional delayed imaging on a 52-year-old man with sparganosis and a 70-year-old man with tuberculous meningitis. To the best of our knowledge, this is the first report on dual time point PET/CT imaging in patients with cerebral sparganosis and tuberculous meningitis.

Metabolic Brain Network Analysis of Hypothyroidism Symptom Based on [18F]FDG-PET of Rats.

Science.gov (United States)

Wan, Hongkai; Tan, Ziyu; Zheng, Qiang; Yu, Jing

2018-03-12

Recent researches have demonstrated the value of using 2-deoxy-2-[ 18 F]fluoro-D-glucose ([ 18 F]FDG) positron emission tomography (PET) imaging to reveal the hypothyroidism-related damages in local brain regions. However, the influence of hypothyroidism on the entire brain network is barely studied. This study focuses on the application of graph theory on analyzing functional brain networks of the hypothyroidism symptom. For both the hypothyroidism and the control groups of Wistar rats, the functional brain networks were constructed by thresholding the glucose metabolism correlation matrices of 58 brain regions. The network topological properties (including the small-world properties and the nodal centralities) were calculated and compared between the two groups. We found that the rat brains, like human brains, have typical properties of the small-world network in both the hypothyroidism and the control groups. However, the hypothyroidism group demonstrated lower global efficiency and decreased local cliquishness of the brain network, indicating hypothyroidism-related impairment to the brain network. The hypothyroidism group also has decreased nodal centrality in the left posterior hippocampus, the right hypothalamus, pituitary, pons, and medulla. This observation accorded with the hypothyroidism-related functional disorder of hypothalamus-pituitary-thyroid (HPT) feedback regulation mechanism. Our research quantitatively confirms that hypothyroidism hampers brain cognitive function by causing impairment to the brain network of glucose metabolism. This study reveals the feasibility and validity of applying graph theory method to preclinical [ 18 F]FDG-PET images and facilitates future study on human subjects.

Simulation study comparing the helmet-chin PET with a cylindrical PET of the same number of detectors

Science.gov (United States)

Ahmed, Abdella M.; Tashima, Hideaki; Yoshida, Eiji; Nishikido, Fumihiko; Yamaya, Taiga

2017-06-01

There is a growing interest in developing brain PET scanners with high sensitivity and high spatial resolution for early diagnosis of neurodegenerative diseases and studies of brain functions. Sensitivity of the PET scanner can be improved by increasing the solid angle. However, conventional PET scanners are designed based on a cylindrical geometry, which may not be the most efficient design for brain imaging in terms of the balance between sensitivity and cost. We proposed a dedicated brain PET scanner based on a hemispheric shape detector and a chin detector (referred to as the helmet-chin PET), which is designed to maximize the solid angle by increasing the number of lines-of-response in the hemisphere. The parallax error, which PET scanners with a large solid angle tend to have, can be suppressed by the use of depth-of-interaction detectors. In this study, we carry out a realistic evaluation of the helmet-chin PET using Monte Carlo simulation based on the 4-layer GSO detector which consists of a 16  ×  16  ×  4 array of crystals with dimensions of 2.8  ×  2.8  ×  7.5 mm3. The purpose of this simulation is to show the gain in imaging performance of the helmet-chin PET compared with the cylindrical PET using the same number of detectors in each configuration. The sensitivity of the helmet-chin PET evaluated with a cylindrical phantom has a significant increase, especially at the top of the (field-of-view) FOV. The peak-NECR of the helmet-chin PET is 1.4 times higher compared to the cylindrical PET. The helmet-chin PET provides relatively low noise images throughout the FOV compared to the cylindrical PET which exhibits enhanced noise at the peripheral regions. The results show the helmet-chin PET can significantly improve the sensitivity and reduce the noise in the reconstructed images.

3D Surface Realignment Tracking for Medical Imaging: A Phantom Study with PET Motion Correction

DEFF Research Database (Denmark)

Olesen, Oline Vinter; Paulsen, Rasmus Reinhold; Jensen, Rasmus Ramsbøl

2011-01-01

We present a complete system for motion correction in high resolution brain positron emission tomography (PET) imaging. It is based on a compact structured light scanner mounted above the patient tunnel of the Siemens High Resolution Research Tomograph PET brain scanner. The structured light system...... is equipped with a near infrared diode and uses phase-shift interferometry to compute 3D representations of the forehead of the patient. These 3D point clouds are progressively aligned to a reference surface and thereby giving the head pose changes. The estimated pose changes are used to reposition a sequence...... of recon- structed PET frames. To align the structured light system with the PET coordinate system a novel registration algorithm based on the PET trans- mission scan and an initial surface has been developed. The performance of the complete setup has been evaluated using a custom made phantom based...

The use of amino acid PET and conventional MRI for monitoring of brain tumor therapy

DEFF Research Database (Denmark)

Galldiks, Norbert; Law, Ian; Pope, Whitney B

2017-01-01

Routine diagnostics and treatment monitoring of brain tumors is usually based on contrast-enhanced MRI. However, the capacity of conventional MRI to differentiate tumor tissue from posttherapeutic effects following neurosurgical resection, chemoradiation, alkylating chemotherapy, radiosurgery, and......),O-(2-[18F]fluoroethyl)-l-tyrosine (FET) and 3,4-dihydroxy-6-[18F]-fluoro-l-phenylalanine (FDOPA) and summarizes investigations regarding monitoring of brain tumor therapy......./or immunotherapy may be limited. Metabolic imaging using PET can provide relevant additional information on tumor metabolism, which allows for more accurate diagnostics especially in clinically equivocal situations. This review article focuses predominantly on the amino acid PET tracers11C-methyl-l-methionine (MET...

PET-MRI and multimodal cancer imaging

International Nuclear Information System (INIS)

Wang Taisong; Zhao Jinhua; Song Jianhua

2011-01-01

Multimodality imaging, specifically PET-CT, brought a new perspective into the fields of clinical imaging. Clinical cases have shown that PET-CT has great value in clinical diagnosis and experimental research. But PET-CT still bears some limitations. A major drawback is that CT provides only limited soft tissue contrast and exposes the patient to a significant radiation dose. MRI overcome these limitations, it has excellent soft tissue contrast, high temporal and spatial resolution and no radiation damage. Additionally, since MRI provides also functional information, PET-MRI will show a new direction of multimodality imaging in the future. (authors)