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Sample records for 15o brain pet

  1. Assessment of rodent brain activity using combined [(15)O]H2O-PET and BOLD-fMRI.

    PubMed

    Wehrl, Hans F; Martirosian, Petros; Schick, Fritz; Reischl, Gerald; Pichler, Bernd J

    2014-04-01

    The study of brain activation in small animals is of high interest for neurological research. In this study, we proposed a protocol to monitor brain activation in rats following whisker stimulation using the short half-life PET tracer [(15)O]H2O as a marker for cerebral blood flow. This technique enables the study of baseline and activation conditions in fast succession within the same scanning session. Furthermore, we compared the results obtained from PET imaging with additional BOLD-fMRI data acquired in the same animals within the same anesthetic session in immediate succession. Although the maximum relative signal changes during brain activity observed with PET were substantially higher compared to the BOLD-fMRI results, statistical analyses showed that the number of activated voxels in PET was lower compared to the fMRI measurements. Furthermore, there was a difference in the activation centers in both the shape and location between PET and fMRI. The discrepancy in the number of activated voxels could be attributed to a lower overall contrast-to-noise ratio of the PET images compared to BOLD-fMRI, whereas the difference in the spatial location indicates a more fundamental process, involving the different physiological origins of the PET and BOLD-fMRI response. This study clearly demonstrates that [(15)O]H2O-PET activation studies may be performed in small laboratory animals, and shows the complementary nature of studying brain activation using [(15)O]H2O-PET and fMRI.

  2. A Network Analysis of 15O-H2O PET Reveals Deep Brain Stimulation Effects on Brain Network of Parkinson's Disease

    PubMed Central

    Park, Hae-Jeong; Park, Bumhee; Kim, Hae Yu; Oh, Maeng-Keun; Kim, Joong Il; Yoon, Misun; Lee, Jong Doo

    2015-01-01

    Purpose As Parkinson's disease (PD) can be considered a network abnormality, the effects of deep brain stimulation (DBS) need to be investigated in the aspect of networks. This study aimed to examine how DBS of the bilateral subthalamic nucleus (STN) affects the motor networks of patients with idiopathic PD during motor performance and to show the feasibility of the network analysis using cross-sectional positron emission tomography (PET) images in DBS studies. Materials and Methods We obtained [15O]H2O PET images from ten patients with PD during a sequential finger-to-thumb opposition task and during the resting state, with DBS-On and DBS-Off at STN. To identify the alteration of motor networks in PD and their changes due to STN-DBS, we applied independent component analysis (ICA) to all the cross-sectional PET images. We analysed the strength of each component according to DBS effects, task effects and interaction effects. Results ICA blindly decomposed components of functionally associated distributed clusters, which were comparable to the results of univariate statistical parametric mapping. ICA further revealed that STN-DBS modifies usage-strengths of components corresponding to the basal ganglia-thalamo-cortical circuits in PD patients by increasing the hypoactive basal ganglia and by suppressing the hyperactive cortical motor areas, ventrolateral thalamus and cerebellum. Conclusion Our results suggest that STN-DBS may affect not only the abnormal local activity, but also alter brain networks in patients with PD. This study also demonstrated the usefulness of ICA for cross-sectional PET data to reveal network modifications due to DBS, which was not observable using the subtraction method. PMID:25837179

  3. Brain activation during dichotic presentations of consonant-vowel and musical instrument stimuli: a 15O-PET study.

    PubMed

    Hugdahl, K; Brønnick, K; Kyllingsbaek, S; Law, I; Gade, A; Paulson, O B

    1999-04-01

    Dichotic listening means that two different stimuli are presented at the same time, one in each ear. This technique is frequently used in experimental and clinical studies as a measure of hemispheric specialization. The primary aim of the present study was to record regional changes in the distribution of cerebral blood flow (CBF) with the 15O-PET technique to dichotically presented consonant-vowel (CV) and musical instrument stimuli, in order to test the basic assumption of differential hemispheric involvement when stimuli presented to one ear dominate over stimuli presented in the other ear. All stimuli were 380 ms in duration with a 1000 ms interstimulus interval, and were presented in blocks of either CV-syllable or musical instrument pairs. Twelve normal healthy subjects had to press a button whenever they detected a CV-syllable or a musical instrument target in a stream of CV- and musical instrument distractor stimuli. The targets appeared equally often in the right and left ear channel. The CV-syllable and musical instrument targets activated bilateral areas in the superior temporal gyri. However, there were significant interactions with regard to asymmetry of the magnitude of peak activation in the significant activation clusters. The CV-syllables resulted in greater neural activation in the left temporal lobe while the musical instruments resulted in greater neural activation in the right temporal lobe. Within-subjects correlations between magnitude of dichotic listening and CBF asymmetry were, however, non-significant. The changes in neural activation were closely mimicked by the performance data which showed a right ear superiority in response accuracy for the CV-syllables, and a left ear superiority for the musical instruments. In addition to the temporal lobe activations, there were activation tendencies in the left inferior frontal lobe, right dorsolateral prefrontal cortex, left occipital lobe, and cerebellum.

  4. Evaluation of the ECAT EXACT HR{sup +} 3D PET scanner in {sup 15}O-water brain activation studies

    SciTech Connect

    Moreno-Cantu, J.J.; Thompson, C.J.; Zatorre, R.J.

    1996-12-31

    We evaluated the performance of the ECAT EXACT HR{sup +} 3D whole body PET scanner when employed to measure brain function using {sup 15}O-water-bolus activation protocols in single data acquisition sessions. Using vibrotactile and auditory stimuli as independent activation tasks, we studied the scanner`s performance under different imaging conditions in four healthy volunteers. Cerebral blood flow images were acquired from each volunteer using {sup 15}O-water-bolus injections of activity varying from 5 to 20mCi. Performance characteristics. The scanner`s dead time grew linearly with injected dose from 10% to 25%. Random events varied from 30% to 50% of the detected events. Scattered events were efficiently corrected at all doses. Noise-effective-count curves plateau at about 15mCi. One-session 12-injection bolus PET activation protocol. Using an acquisition protocol that accounts for the scanner`s performance and the practical aspects of imaging volunteers and patients in one session, we assessed the correlation between the statistical significance of activation foci and the dose per injection used The one-session protocol employs 12 bolus injections per subject. We present evidence suggesting that 15-20mCi is the optimal dose per injection to be used routinely in one-time scanning sessions.

  5. Noninvasive functional brain mapping by change-distribution analysis of averaged PET images of H/sub 2//sup 15/O tissue activity

    SciTech Connect

    Fox, P.T.; Mintun, M.A.

    1989-02-01

    Change-distribution analysis and intersubject averaging of subtracted positron emission tomography (PET) images are new techniques for detecting, localizing, and quantifying state-dependent focal transients in neuronal activity. We previously described their application to cerebral blood flow images (intravenous bolus H/sub 2//sup 15/O, Kety autoradiographic model). We now describe their application to images of H/sub 2//sup 15/O regional tissue activity without conversion to units of blood flow. The sensitivity and specificity of response detection and the accuracy of response localization were virtually identical for the two types of images. Response magnitude expressed in percent change from rest was slightly, but consistently smaller in tissue-activity images. Response magnitude expressed in z-score was the same for the two-image types. Most research and clinical applications of functional brain mapping can employ images of H215O tissue activity (intravenous bolus, 40-sec nondynamic scan) without conversion to units of blood flow. This eliminates arterial blood sampling, thereby simplifying and minimizing the invasivity of the PET procedure.

  6. Estimation of arterial input by a noninvasive image derived method in brain H2 15O PET study: confirmation of arterial location using MR angiography

    NASA Astrophysics Data System (ADS)

    Muinul Islam, Muhammad; Tsujikawa, Tetsuya; Mori, Tetsuya; Kiyono, Yasushi; Okazawa, Hidehiko

    2017-06-01

    A noninvasive method to estimate input function directly from H2 15O brain PET data for measurement of cerebral blood flow (CBF) was proposed in this study. The image derived input function (IDIF) method extracted the time-activity curves (TAC) of the major cerebral arteries at the skull base from the dynamic PET data. The extracted primordial IDIF showed almost the same radioactivity as the arterial input function (AIF) from sampled blood at the plateau part in the later phase, but significantly lower radioactivity in the initial arterial phase compared with that of AIF-TAC. To correct the initial part of the IDIF, a dispersion function was applied and two constants for the correction were determined by fitting with the individual AIF in 15 patients with unilateral arterial stenoocclusive lesions. The area under the curves (AUC) from the two input functions showed good agreement with the mean AUCIDIF/AUCAIF ratio of 0.92  ±  0.09. The final products of CBF and arterial-to-capillary vascular volume (V 0) obtained from the IDIF and AIF showed no difference, and had with high correlation coefficients.

  7. Cortical deactivations during gastric fundus distension in health: visceral pain-specific response or attenuation of 'default mode' brain function? A H2 15O-PET study.

    PubMed

    van Oudenhove, L; Vandenberghe, J; Dupont, P; Geeraerts, B; Vos, R; Bormans, G; van Laere, K; Fischler, B; Demyttenaere, K; Janssens, J; Tack, J

    2009-03-01

    Gastric distension activates a cerebral network including brainstem, thalamus, insula, perigenual anterior cingulate, cerebellum, ventrolateral prefrontal cortex and potentially somatosensory regions. Cortical deactivations during gastric distension have hardly been reported. To describe brain areas of decreased activity during gastric fundus distension compared to baseline, using data from our previously published study (Gastroenterology, 128, 2005 and 564). H(2) (15)O-brain positron emission tomography was performed in 11 healthy volunteers during five conditions (random order): (C(1)) no distension (baseline); isobaric distension to individual thresholds for (C(2)) first, (C(3)) marked, (C(4)) unpleasant sensation and (C(5)) sham distension. Subtraction analyses were performed (in SPM2) to determine deactivated areas during distension compared to baseline, with a threshold of P(uncorrected_voxel_level) < 0.001 and P(corrected_cluster_level) < 0.05. Baseline-maximal distension (C(1)-C(4)) yielded significant deactivations in: (i) bilateral occipital, lateral parietal and temporal cortex as well as medial parietal lobe (posterior cingulate and precuneus) and medial temporal lobe (hippocampus and amygdala), (ii) right dorsolateral and dorso- and ventromedial PFC, (iii) left subgenual ACC and bilateral caudate head. Intragastric pressure and epigastric sensation score correlated negatively with brain activity in similar regions. The right hippocampus/amygdala deactivation was specific to sham. Gastric fundus distension in health is associated with extensive cortical deactivations, besides the activations described before. Whether this represents task-independent suspension of 'default mode' activity (as described in various cognitive tasks) or an visceral pain/interoception-specific process remains to be elucidated.

  8. Evaluation of the ECAT EXACT HR+ 3-D PET scanner in H2(15)O brain activation studies: dose fractionation strategies for rCBF and signal enhancing protocols.

    PubMed

    Moreno-Cantú, J J; Thompson, C J; Zatorre, R J

    1998-12-01

    We evaluated the performance of the ECAT EXACT HR+ 3-D whole-body positron emission tomography (PET) scanner when employed to measure brain function using H2(15)O bolus activation protocols that are completed in single same-day data acquisition sessions. Using vibrotactile and auditory stimuli as independent activation tasks, we studied the scanner performance under different imaging conditions in five healthy volunteers. Cerebral blood flow images were acquired from each volunteer using H2(15)O bolus injections of activity varying from 5-20 mCi. One-session dose-fractionation strategies were analyzed for rCBF, standard activity-concentration, switched, and cold-bolus/switched protocols. Performance characteristics. The scanner dead time grew linearly with injected dose from 10% to 25%. Random events varied from 30% to 50% of the detected events. Random and scattered events were corrected adequately at all doses. Estimated noise-effective-count curves plateau at about 10 mCi. One-session 12-injection bolus PET activation protocols. Using an acquisition protocol that accounts for the scanner performance and the practical aspects of imaging volunteers and neurological patients in a single same-day session, we assessed the correlation between the significance of activation foci and the dose/injection used. The one-session protocol employs 12 bolus injections/subject. We present evidence suggesting that when an rCBF protocol is used, image noise is reduced significantly when the activity injected increases from 5 to 10 mCi. Increasing the dose from 10 to 15 or 20 mCi yielded further but smaller reductions. Our observations also suggest that image noise will be strongly reduced if a 20-mCi dose/injection is used when data are collected using protocols that employ long acquisition times such as a switched or a cold-bolus/switched protocol.

  9. Reciprocal Benefits of Mass-Univariate and Multivariate Modeling in Brain Mapping: Applications to Event-Related Functional MRI, H2 15O-, and FDG-PET

    PubMed Central

    Habeck, Christian G.

    2006-01-01

    In brain mapping studies of sensory, cognitive, and motor operations, specific waveforms of dynamic neural activity are predicted based on theoretical models of human information processing. For example in event-related functional MRI (fMRI), the general linear model (GLM) is employed in mass-univariate analyses to identify the regions whose dynamic activity closely matches the expected waveforms. By comparison multivariate analyses based on PCA or ICA provide greater flexibility in detecting spatiotemporal properties of experimental data that may strongly support alternative neuroscientific explanations. We investigated conjoint multivariate and mass-univariate analyses that combine the capabilities to (1) verify activation of neural machinery we already understand and (2) discover reliable signatures of new neural machinery. We examined combinations of GLM and PCA that recover latent neural signals (waveforms and footprints) with greater accuracy than either method alone. Comparative results are illustrated with analyses of real fMRI data, adding to Monte Carlo simulation support. PMID:23165047

  10. Cortical activation in profoundly deaf patients during cochlear implant stimulation demonstrated by H sub 2 (15)O PET

    SciTech Connect

    Herzog, H.; Lamprecht, A.; Kuehn, A.R.; Roden, W.; Vosteen, K.H.; Feinendegen, L.E. )

    1991-05-01

    Cochlear implants (CIs) are used to provide sensations of sound to profoundly deaf patients. The performance of the CI is assessed mainly by the subjective reports of patients. The aim of this study was to look for objective cortical responses to the stimulation of the CI. Two postlingually and two prelingually deaf patients were investigated by positron emission tomography (PET) using {sup 15}O-labeled water (H{sub 2}{sup 15}O) to determine the regional cerebral blood flow (rCBF). Instead of quantifying rCBF in absolute terms, it was estimated by referring the regional tissue concentration of H{sub 2}{sup 15}O to the mean whole brain concentration. CI stimulation encoded from white noise and sequential words led to an increased rCBF in the primary and secondary (Wernicke) auditory cortex. Relative elevations of up to 33% were observed bilaterally, although they were higher contralateral to the CI. These results were obtained not only in the postlingually deaf patients but also in two patients who had never been able to hear. Thus, it could be demonstrated that PET measurements of cerebral H{sub 2}{sup 15}O distribution yield objective responses of the central auditory system during electrical stimulation by CIs in profoundly deaf patients.

  11. Validity of using a 3-dimensional PET scanner during inhalation of 15O-labeled oxygen for quantitative assessment of regional metabolic rate of oxygen in man

    NASA Astrophysics Data System (ADS)

    Hori, Yuki; Hirano, Yoshiyuki; Koshino, Kazuhiro; Moriguchi, Tetsuaki; Iguchi, Satoshi; Yamamoto, Akihide; Enmi, Junichiro; Kawashima, Hidekazu; Zeniya, Tsutomu; Morita, Naomi; Nakagawara, Jyoji; Casey, Michael E.; Iida, Hidehiro

    2014-09-01

    Use of 15O labeled oxygen (15O2) and positron emission tomography (PET) allows quantitative assessment of the regional metabolic rate of oxygen (CMRO2) in vivo, which is essential to understanding the pathological status of patients with cerebral vascular and neurological disorders. The method has, however, been challenging, when a 3D PET scanner is employed, largely attributed to the presence of gaseous radioactivity in the trachea and the inhalation system, which results in a large amount of scatter and random events in the PET assessment. The present study was intended to evaluate the adequacy of using a recently available commercial 3D PET scanner in the assessment of regional cerebral radioactivity distribution during an inhalation of 15O2. Systematic experiments were carried out on a brain phantom. Experiments were also performed on a healthy volunteer following a recently developed protocol for simultaneous assessment of CMRO2 and cerebral blood flow, which involves sequential administration of 15O2 and C15O2. A particular intention was to evaluate the adequacy of the scatter-correction procedures. The phantom experiment demonstrated that errors were within 3% at the practically maximum radioactivity in the face mask, with the greatest radioactivity in the lung. The volunteer experiment demonstrated that the counting rate was at peak during the 15O gas inhalation period, within a verified range. Tomographic images represented good quality over the entire FOV, including the lower part of the cerebral structures and the carotid artery regions. The scatter-correction procedures appeared to be important, particularly in the process to compensate for the scatter originating outside the FOV. Reconstructed images dramatically changed if the correction was carried out using inappropriate procedures. This study demonstrated that accurate reconstruction could be obtained when the scatter compensation was appropriately carried out. This study also suggested the

  12. Validity of using a 3-dimensional PET scanner during inhalation of 15O-labeled oxygen for quantitative assessment of regional metabolic rate of oxygen in man.

    PubMed

    Hori, Yuki; Hirano, Yoshiyuki; Koshino, Kazuhiro; Moriguchi, Tetsuaki; Iguchi, Satoshi; Yamamoto, Akihide; Enmi, Junichiro; Kawashima, Hidekazu; Zeniya, Tsutomu; Morita, Naomi; Nakagawara, Jyoji; Casey, Michael E; Iida, Hidehiro

    2014-09-21

    Use of 15O labeled oxygen (15O2) and positron emission tomography (PET) allows quantitative assessment of the regional metabolic rate of oxygen (CMRO2) in vivo, which is essential to understanding the pathological status of patients with cerebral vascular and neurological disorders. The method has, however, been challenging, when a 3D PET scanner is employed, largely attributed to the presence of gaseous radioactivity in the trachea and the inhalation system, which results in a large amount of scatter and random events in the PET assessment. The present study was intended to evaluate the adequacy of using a recently available commercial 3D PET scanner in the assessment of regional cerebral radioactivity distribution during an inhalation of 15O2. Systematic experiments were carried out on a brain phantom. Experiments were also performed on a healthy volunteer following a recently developed protocol for simultaneous assessment of CMRO2 and cerebral blood flow, which involves sequential administration of 15O2 and C15O2. A particular intention was to evaluate the adequacy of the scatter-correction procedures. The phantom experiment demonstrated that errors were within 3% at the practically maximum radioactivity in the face mask, with the greatest radioactivity in the lung. The volunteer experiment demonstrated that the counting rate was at peak during the 15O gas inhalation period, within a verified range. Tomographic images represented good quality over the entire FOV, including the lower part of the cerebral structures and the carotid artery regions. The scatter-correction procedures appeared to be important, particularly in the process to compensate for the scatter originating outside the FOV. Reconstructed images dramatically changed if the correction was carried out using inappropriate procedures. This study demonstrated that accurate reconstruction could be obtained when the scatter compensation was appropriately carried out. This study also suggested the

  13. Real-time iterative monitoring of radiofrequency ablation tumor therapy with 15O-water PET imaging.

    PubMed

    Bao, Ande; Goins, Beth; Dodd, Gerald D; Soundararajan, Anuradha; Santoyo, Cristina; Otto, Randal A; Davis, Michael D; Phillips, William T

    2008-10-01

    A method that provides real-time image-based monitoring of solid tumor therapy to ensure complete tumor eradication during image-guided interventional therapy would be a valuable tool. The short, 2-min half-life of (15)O makes it possible to perform repeated PET imaging at 20-min intervals at multiple time points before and after image-guided therapy. In this study, (15)O-water PET was evaluated as a tool to provide real-time feedback and iterative image guidance to rapidly monitor the intratumoral coverage of radiofrequency (RF) ablation therapy. Tumor RF ablation therapy was performed on head and neck squamous cell carcinoma (SCC) xenograft tumors (length, approximately 23 mm) in 6 nude rats. The tumor in each animal was ablated with RF (1-cm active size ablation catheter, 70 degrees C for 5 min) twice in 2 separate tumor regions with a 20-min separation. The (15)O-water PET images were acquired before RF ablation and after the first RF and second RF ablations using a small-animal PET scanner. In each PET session, approximately 100 MBq of (15)O-water in 1.0 mL of saline were injected intravenously into each animal. List-mode PET images were acquired for 7 min starting 20 s before injection. PET images were reconstructed by 2-dimensional ordered-subset expectation maximization into single-frame images and dynamic images at 10 s/frame. PET images were displayed and analyzed with software. Pre-RF ablation images demonstrate that (15)O-water accumulates in tumors with (15)O activity reaching peak levels immediately after administration. After RF ablation, the ablated region had almost zero activity, whereas the unablated tumor tissue continued to have a high (15)O-water accumulation. Using image feedback, the RF probe was repositioned to a tumor region with residual (15)O-water uptake and then ablated. The second RF ablation in this new region of the tumor resulted in additional ablation of the solid tumor, with a corresponding decrease in activity on the (15)O

  14. Quantitative comparison of functional contrast from BOLD-weighted spin-echo and gradient-echo echoplanar imaging at 1.5 Tesla and H2 15O PET in the whole brain.

    PubMed

    Lowe, M J; Lurito, J T; Mathews, V P; Phillips, M D; Hutchins, G D

    2000-09-01

    Spin-echo and gradient-echo echoplanar functional magnetic resonance imaging (fMRI) studies at 1.5 Tesla (T) were used to obtain blood oxygenation level-dependent (BOLD) contrast images of the whole brain in seven strongly right-handed women during execution of a complex motor task. Five subjects underwent subsequent H215O positron emission tomography (PET) studies while performing the same task. Group-averaged results for changes in the MRI relaxation rates R2* and R2 at 1.5T in response to neuronal activation in nine cortical, subcortical, and cerebellar motor regions are reported. Results for each method are grouped according to tissue type-cerebral cortex (precentral gyrus and supplementary motor area), subcortical regions (thalamus and putamen), and cerebellar cortex (superior lobule). The observed changes in R2* from activation-induced oxygenation changes were more variable across brain regions with different tissue characteristics than observed changes in R2. The ratio of deltaR2* to deltaR2 was 3.3 +/- 0.9 for cerebral cortex and 2.0 +/- 0.6 for subcortical tissue. deltaR2*, deltaR2, and relative blood flow changes were deltaR2* = -0.201 +/- 0.040 (s-1), deltaR2 = -0.064 +/- 0.011 s(-1), and deltaf/f = 16.7 +/- 0.8% in the cerebral cortex; deltaR2* = -0.100 +/- 0.026 s(-1), deltaR2 = -0.049 +/- 0.009 s(-1), and deltaf/f = 9.4 +/- 0.7% in the subcortical regions; and deltaR2* = -0.215 +/- 0.093 s(-1), deltaR2 = -0.069 +/- 0.012 s(-1), and deltaf/f = 16.2 +/- 1.2% in the cerebellar cortex.

  15. Quantitative agreement between [(15)O]H2O PET and model free QUASAR MRI-derived cerebral blood flow and arterial blood volume.

    PubMed

    Heijtel, D F R; Petersen, E T; Mutsaerts, H J M M; Bakker, E; Schober, P; Stevens, M F; van Berckel, B N M; Majoie, C B L M; Booij, J; van Osch, M J P; van Bavel, E T; Boellaard, R; Lammertsma, A A; Nederveen, A J

    2016-04-01

    The purpose of this study was to assess whether there was an agreement between quantitative cerebral blood flow (CBF) and arterial cerebral blood volume (CBVA) measurements by [(15)O]H2O positron emission tomography (PET) and model-free QUASAR MRI. Twelve healthy subjects were scanned within a week in separate MRI and PET imaging sessions, after which quantitative and qualitative agreement between both modalities was assessed for gray matter, white matter and whole brain region of interests (ROI). The correlation between CBF measurements obtained with both modalities was moderate to high (r(2): 0.28-0.60, P < 0.05), although QUASAR significantly underestimated CBF by 30% (P < 0.001). CBVA was moderately correlated (r(2): 0.28-0.43, P < 0.05), with QUASAR yielding values that were only 27% of the [(15)O]H2O-derived values (P < 0.001). Group-wise voxel statistics identified minor areas with significant contrast differences between [(15)O]H2O PET and QUASAR MRI, indicating similar qualitative CBVA and CBF information by both modalities. In conclusion, the results of this study demonstrate that QUASAR MRI and [(15)O]H2O PET provide similar CBF and CBVA information, but with systematic quantitative discrepancies. Copyright © 2016 John Wiley & Sons, Ltd.

  16. The effect of activity outside the field-of-view on image signal-to-noise ratio for 3D PET with 15O

    NASA Astrophysics Data System (ADS)

    Ibaraki, Masanobu; Sugawara, Shigeki; Nakamura, Kazuhiro; Kinoshita, Fumiko; Kinoshita, Toshibumi

    2011-05-01

    Activity outside the field-of-view (FOV) degrades the count rate performance of 3D PET and consequently reduces signal-to-noise ratios (SNRs) of reconstructed images. The aim of this study was to evaluate a neck-shield installed in a 3D PET scanner for reducing the effect of the outside FOV activity. Specifically, we compared brain PET scans (15O2 and H215O) with and without the use of the neck-shield. Image SNRs were directly estimated by a sinogram bootstrap method. The bootstrap analysis showed that the use of the neck-shield improved the SNR by 8% and 19% for H215O and 15O2, respectively. The SNR improvements were predominantly due to the reduction of the random count rates. Noise equivalent count rate (NECR) analysis provided SNR estimates that were very similar with the bootstrap-based results for H215O, but not for 15O2. This discrepancy may be due to the fundamental difference between the two methods: the bootstrap method directly calculates the local SNR of reconstructed images, whereas the NECR calculation is based on the whole-gantry count rates, indicating a limitation of the conventional NECR-based method as a tool for assessing the image SNR. Although quantitative parameters, e.g. cerebral blood flow, did not differ when examined with and without the neck-shield, the use of the shield for brain 15O study is recommended in terms of the image SNR.

  17. A continuous [{sup 15}O]H{sub 2}O production and infusion system for PET imaging

    SciTech Connect

    Sajjad, Munawwar; Liow, Jeih-San

    1999-06-10

    A system for continuous production and infusion of [{sup 15}O]H{sub 2}O has been designed for PET cerebral blood flow studies. The injection system consists of a four-port-two-position valve, two Horizon Nxt infusion pumps, and a sterile 50 ml vial. The variation of the production of [{sup 15}O]H{sub 2}O was <1%. The variation of activity delivered measured by scanner counts during the steady state period was <2%.

  18. Production of an 15O beam using a stable oxygen ion beam for in-beam PET imaging

    NASA Astrophysics Data System (ADS)

    Mohammadi, Akram; Yoshida, Eiji; Tashima, Hideaki; Nishikido, Fumihiko; Inaniwa, Taku; Kitagawa, Atsushi; Yamaya, Taiga

    2017-03-01

    In advanced ion therapy, the 15O ion beam is a promising candidate to treat hypoxic tumors and simultaneously monitor the delivered dose to a patient using PET imaging. This study aimed at production of an 15O beam by projectile fragmentation of a stable 16O beam in an optimal material, followed by in-beam PET imaging using a prototype OpenPET system, which was developed in the authors' group. The study was carried out in three steps: selection of the optimal target based on the highest production rate of 15O fragments; experimental production of the beam using the optimal target in the Heavy Ion Medical Accelerator Chiba (HIMAC) secondary beam course; and realization of in-beam PET imaging for the produced beam. The optimal target evaluations were done using the Monte Carlo simulation code PHITS. The fluence and mean energy of the secondary particles were simulated and the optimal target was selected based on the production rate of 15O fragments. The highest production rate of 15O was observed for a liquid hydrogen target, 3.27% for a 53 cm thick target from the 16O beam of 430 MeV/u. Since liquid hydrogen is not practically applicable in the HIMAC secondary beam course a hydrogen-rich polyethylene material, which was the second optimal target from the simulation results, was selected as the experimental target. Three polyethylene targets with thicknesses of 5, 11 or 14 cm were used to produce the 15O beam without any degrader in the beam course. The highest production rate was measured as around 0.87% for the 11 cm thick polyethylene target from the 16O beam of 430 MeV/u when the angular acceptance and momentum acceptance were set at ±13 mrad and ±2.5%, respectively. The purity of the produced beam for the three targets were around 75%, insufficient for clinical application, but it was increased to 97% by inserting a wedge shape aluminum degrader with a thickness of 1.76 cm into the beam course and that is sufficiently high. In-beam PET imaging was also

  19. Activation of a residual cortical network during painful stimulation in long-term postanoxic vegetative state: a 15O-H2O PET study.

    PubMed

    Kassubek, Jan; Juengling, Freimut D; Els, Thomas; Spreer, Joachim; Herpers, Martin; Krause, Thomas; Moser, Ernst; Lücking, Carl H

    2003-08-15

    Survivors of prolonged cerebral anoxia often remain in the persistent vegetative state (PVS). In this study, long-term PVS patients were investigated by 15O-H(2)O PET to analyze their central processing of pain. The study was approved by the local Ethics Committee, the experiments were performed in accordance with the Helsinki Declaration of 2000. Seven patients remaining in PVS of anoxic origin for a mean of 1.6 years (range 0.25-4 years) were investigated. We performed functional PET of the brain using 15O-labelled water during electrical nociceptive stimulation. Additionally, a brain metabolism study using 18F-fluorodeoxyglucose (FDG) PET and multi-sequence MRI (including a 3-D data set) were acquired in all patients. PET data were analyzed by means of Statistical Parametric Mapping (SPM99) and coregistered to a study-specific brain template. MRI and FDG PET showed severe cortical impairment at the structural and the functional level, that is, general atrophy of various degrees and a widespread significant hypometabolism, respectively. Pain-induced activation (hyperperfusion) was found in the posterior insula/secondary somatosensory cortex (SII), postcentral gyrus/primary somatosensory cortex (SI), and the cingulate cortex contralateral to the stimulus and in the posterior insula ipsilateral to the stimulus (P<0.05, small-volume-corrected). No additional areas of the complex pain-processing matrix were significantly activated. In conclusion, the regional activity found at the cortical level indicates that a residual pain-related cerebral network remains active in long-term PVS patients.

  20. Evaluation of coronary endothelial dysfunction in healthy young smokers: Cold pressor test using [(15)O]H(2)O PET.

    PubMed

    Hwang, Kyung Hoon; Lee, Byeong-Il; Kim, Su Jin; Lee, Jae Sung; Lee, Dong Soo

    2009-01-01

    The purpose of this study was to investigate coronary endothelial dysfunction in young healthy smokers by measuring myocardial blood flow (MBF) using [(15)O]H(2)O-PET. The study population was 18 young male volunteers consisted of 9 smokers (age: 23.8+/-1.1yr) and 9 non-smokers (age: 25.0+/-2.5yr). The smokers had been smoking cigarettes for 6.6+/-2.5 pack years. Myocardial [(15)O]H(2)O-PET was performed at rest, during cold (5 degrees C) pressor stimulation and during adenosine infusion. Left ventricular (LV) input function and tissue time-activity curves were obtained by drawing region of interest (ROI) on the LV blood pool and myocardium images obtained by non-negative matrix factorization (NMF) of dynamic [(15)O]H(2)O-PET data, and MBF was calculated using these time-activity curves and single compartmental model. There were no significant difference in resting MBF between two groups (smokers: 1.43+/-0.41 and non-smokers: 1.37+/-0.41ml/g/min; P=NS). However, during cold pressor stimulation, MBF in smokers was significantly lower than that in non-smokers (1.25+/-0.33 vs. 1.59+/-0.29ml/g/min; P=0.019). MBF changed to 90+/-24% of resting MBF in smokers and 122+/-28% in non-smokers. The difference in the ratio of cold pressor MBF to basal MBF between two groups was also significant (P=0.024). During adenosine infusion, however, hyperemic MBF did not differ significantly between smokers and non-smokers (5.81+/-1.99 vs. 5.03+/-1.27ml/g/min; P=NS). This study shows that [(15)O]H(2)O PET analysis can reveal that endothelial dysfunction occurs in even young smokers of about 6 pack years.

  1. Optimization of methods for quantification of rCBF using high-resolution [15O]H2O PET images

    NASA Astrophysics Data System (ADS)

    Walker, M. D.; Feldmann, M.; Matthews, J. C.; Anton-Rodriguez, J. M.; Wang, S.; Koepp, M. J.; Asselin, M.-C.

    2012-04-01

    This study aimed to derive accurate estimates of regional cerebral blood flow (rCBF) from noisy dynamic [15O]H2O PET images acquired on the high-resolution research tomograph, while retaining as much as possible the high spatial resolution of this brain scanner (2-3 mm) in parametric maps of rCBF. The PET autoradiographic method and generalized linear least-squares (GLLS), with fixed or extended to include spatially variable estimates of the dispersion of the measured input function, were compared to nonlinear least-squares (NLLS) for rCBF estimation. Six healthy volunteers underwent two [15O]H2O PET scans with continuous arterial blood sampling. rCBF estimates were obtained from three image reconstruction methods (one analytic and two iterative, of which one includes a resolution model) to which a range of post-reconstruction filters (3D Gaussian: 2, 4 and 6 mm FWHM) were applied. The optimal injected activity was estimated to be around 11 MBq kg-1 (800 MBq) by extrapolation of patient-specific noise equivalent count rates. Whole-brain rCBF values were found to be relatively insensitive to the method of reconstruction and rCBF quantification. The grey and white matter rCBF for analytic reconstruction and NLLS were 0.44 ± 0.03 and 0.15 ± 0.03 mL min-1 cm-3, respectively, in agreement with literature values. Similar values were obtained from the other methods. For generation of parametric images using GLLS or the autoradiographic method, a filter of ⩾4 mm was required in order to suppress noise in the PET images which otherwise produced large biases in the rCBF estimates.

  2. An apparatus for the preparation of [{sup 15}O]-H{sub 2}O for rapid repetitive PET studies

    SciTech Connect

    Dahl, J. R.; Chaly, T. C.; Matacchieri, R. A.; Yee, A.; Dhawan, V.; Horowitz, S.; Jespersen, K.; Margouleff, D.; Eidelberg, D.

    1999-06-10

    The use of [{sup 15}O]-H{sub 2}O to follow changes in cerebral blood flow using PET has become frequent and widespread, requiring an apparatus easily operated by personnel unfamiliar with the physics and chemistry involved. Oxygen-15 is prepared by the {sup 14}N(d,n){sup 15}O nuclear reaction using a target of UHP nitrogen with 1% UHP hydrogen added, contained in a target chamber similar to that reported for the preparation of [{sup 18}F]-F{sub 2}. Nucleogenic {sup 15}O reacts with hydrogen in the target gas to produce [{sup 15}O]-H{sub 2}O. Some of the N target reacts with hydrogen to produce NH{sub 3}, which must be removed. At the end of bombardment (minimum 6 min.) the target gas is released through a small amount of parenteral water which then flows through approximately 50 mg Dowex 50W-X8 resin (100-200 mesh) to remove the NH{sub 3}. Sufficient 23.4% NaCl solution is added to produce an isotonic solution. The isotonic solution is sterilized by filtration through a 0.22 micron filter into an injection syringe which is sent via pneumatic transport to the PET imaging room. The apparatus, which uses a programmable logic controller and four switches to allow the operator to select standby, refill, collect activity, or deliver dose operations of the production process, provides doses of [{sup 15}O]-H{sub 2}O up to 35 mCi/dose at intervals as frequent as seven minutes with minimal radiation exposure to the operators.

  3. Cerebral blood flow with [15O]water PET studies using an image-derived input function and MR-defined carotid centerlines

    NASA Astrophysics Data System (ADS)

    Fung, Edward K.; Carson, Richard E.

    2013-03-01

    Full quantitative analysis of brain PET data requires knowledge of the arterial input function into the brain. Such data are normally acquired by arterial sampling with corrections for delay and dispersion to account for the distant sampling site. Several attempts have been made to extract an image-derived input function (IDIF) directly from the internal carotid arteries that supply the brain and are often visible in brain PET images. We have devised a method of delineating the internal carotids in co-registered magnetic resonance (MR) images using the level-set method and applying the segmentations to PET images using a novel centerline approach. Centerlines of the segmented carotids were modeled as cubic splines and re-registered in PET images summed over the early portion of the scan. Using information from the anatomical center of the vessel should minimize partial volume and spillover effects. Centerline time-activity curves were taken as the mean of the values for points along the centerline interpolated from neighboring voxels. A scale factor correction was derived from calculation of cerebral blood flow (CBF) using gold standard arterial blood measurements. We have applied the method to human subject data from multiple injections of [15O]water on the HRRT. The method was assessed by calculating the area under the curve (AUC) of the IDIF and the CBF, and comparing these to values computed using the gold standard arterial input curve. The average ratio of IDIF to arterial AUC (apparent recovery coefficient: aRC) across 9 subjects with multiple (n = 69) injections was 0.49 ± 0.09 at 0-30 s post tracer arrival, 0.45 ± 0.09 at 30-60 s, and 0.46 ± 0.09 at 60-90 s. Gray and white matter CBF values were 61.4 ± 11.0 and 15.6 ± 3.0 mL/min/100 g tissue using sampled blood data. Using IDIF centerlines scaled by the average aRC over each subjects’ injections, gray and white matter CBF values were 61.3 ± 13.5 and 15.5 ± 3.4 mL/min/100 g tissue. Using global

  4. Brain fluorodeoxyglucose PET in adrenoleukodystrophy.

    PubMed

    Salsano, Ettore; Marotta, Giorgio; Manfredi, Valentina; Giovagnoli, Anna Rita; Farina, Laura; Savoiardo, Mario; Pareyson, Davide; Benti, Riccardo; Uziel, Graziella

    2014-09-09

    To investigate the cerebral glucose metabolism in subjects with X-linked adrenoleukodystrophy (X-ALD) by using brain [(18)F]-fluorodeoxyglucose PET (FDG-PET). Cross-sectional study in which 12 adults with various forms of X-ALD underwent clinical evaluation and brain MRI, followed by brain FDG-PET, neuropsychological assessment, and personality and psychopathology evaluation using the Symptom Checkist-90-Revised (SCL-90-R) and the Millon Clinical Multiaxial Inventory-III (MCMI-III). When compared to healthy control subjects (n = 27) by using Statistical Parametric Mapping 8 software, the patients with X-ALD-with or without brain MRI changes-showed a pattern of increased glucose metabolism in frontal lobes and reduced glucose metabolism in cerebellum and temporal lobe areas. On single case analysis by Scenium software, we found a similar pattern, with significant (p < 0.02) correlation between the degree of hypermetabolism in the frontal lobes of each patient and the corresponding X-ALD clinical scores. With respect to personality, we found that patients with X-ALD usually present with an obsessive-compulsive personality disorder on the MCMI-III, with significant (p < 0.05) correlation between glucose uptake in ventral striatum and severity of score on the obsessive-compulsive subscale. We examined cerebral glucose metabolism using FDG-PET in a cohort of patients with X-ALD and provided definite evidence that in X-ALD the analysis of brain glucose metabolism reveals abnormalities independent from morphologic and signal changes detected by MRI and related to clinical severity. Brain FDG-PET may be a useful neuroimaging technique for the characterization of X-ALD and possibly other leukodystrophies. © 2014 American Academy of Neurology.

  5. A new approach of weighted integration technique based on accumulated images using dynamic PET and H2(15)O

    SciTech Connect

    Yokoi, T.; Kanno, I.; Iida, H.; Miura, S.; Uemura, K. )

    1991-05-01

    We developed a new technique of weighted integration for the measurement of local cerebral blood flow (LCBF) and the blood-tissue partition coefficient (p) using dynamic positron emission tomography (PET) and H2(15)O. The weighted integration in the new technique is carried out on the equation of the first time integration of the Kety-Schmidt differential equation. Practically, serially accumulated images with sequentially prolonged accumulation times are weighted by two arbitrary functions. The weighting functions do not have to be differentiated because of the exclusion of the differential term in the starting equation. Consequently, the method does not require data at the end of the scan. The technique was applied to H2(15)O dynamic PET performed on four normal subjects, and was verified to provide a better signal-to-noise ratio than the previously developed integrated projection (IP) technique. Computer simulations were carried out to investigate the effects of statistical noise, tissue heterogeneity, and time delay and dispersion in arterial input function. The simulation showed that the new technique provided about a 1.4 times lower statistical error in both LCBF and p at 50 ml 100 g-1 min-1 compared to the IP technique, and it should be noted that the new technique was less sensitive to the shape of the weighting functions. The new technique provides a new strategy with respect to the statistical error for estimation of LCBF and p.

  6. Brain PET scan

    MedlinePlus

    ... still during test so that the machine can produce clear images of your brain. You may be asked to read or name letters if your memory is being tested. The test takes between 30 minutes and 2 hours.

  7. Production of {sup 17}F, {sup 15}O and other radioisotopes for PET using a 3 MV electrostatic tandem accelerator

    SciTech Connect

    Roberts, A. D.; Davidson, R. J.; Nickles, R. J.

    1999-06-10

    Target systems for the production of positron emitting radioisotopes used for medical research with positron emission tomography (PET) are under development for a 3 MV electrostatic tandem accelerator (NEC 9SDH-2). This machine is intended primarily for the continuous production of short lived tracers labeled with {sup 15}O (t{sub 1/2}=122 s) or {sup 17}F (t{sub 1/2}=65 s) for determining regional cerebral blood flow in humans. Simple gas, liquid, and solid target systems are presented for the production of [{sup 15}O]H{sub 2}O (yield at saturation 13 mCi/{mu}A), [{sup 17}F]F{sub 2} (22 mCi/{mu}A), [{sup 17}F] fluoride (aq.) (12 mCi/{mu}A), [{sup 18}F]fluoride (aq.) (21 mCi/{mu}A), [{sup 13}N] in graphite (25 mCi/{mu}A), and [{sup 11}C]CO{sub 2} (2.3 mCi/{mu}A). Current limitations on single window targets for each production are discussed.

  8. Is perivetricular hyperintensity region caused by decreased cerebral blood flow?; assessment by {sup 15}O-PET study

    SciTech Connect

    Kaminaga, T.; Hayashida, K.; Ishida, Y.

    1994-05-01

    The clinical significance of the regional cerebral blood flow (rCBF) and oxygen metabolism has not been established in patients who had periventricular hyperintensity (PVH) by magnetic resonance imaging (MRI). The aim of this study is to correlate the results of rCBF and oxygen metabolism by positron emission tomography (PET) with PVH by MRI. The subjects were 27 patients; 16 patient (group I) (male; 7, female; 9, age; 56.8{plus_minus}18.6) with PVH and age matched 11 patients (group II) (male; 6, female; 5, age; 55.3{plus_minus}13.6) without PVH. {sup 15}O-PET study was carried out by Headtome IV and rCBF, cerebral metabolic rate of oxygen (CMRO{sub 2}), oxygen extraction fraction (OEF) of PVH and cerebellum was calculated. T1- and T2-weighted images were obtained in all patients. Angiography was performed over 11 patients. The mean rCBF of group I in PVH (28.5{plus_minus}7.5 ml/100g/min) was significantly (p<0.01) lower than that of group II (38.6{plus_minus}5.7). The mean rCBF of group I and group II in cerebellum were 49.5{plus_minus}9.9 ml/100g/min and 50.2{plus_minus}8.9 respectively. There was no significant difference on CMRO{sub 2} and OEF between group I and group II. In MRI examination, PVH was detected in all group I patients and multiple high intensities were also detected in 7 patients of group I and 4 patients of group II on T2-weighted images. No significant stenosis (more than 75%) was detected in 11 patients by angiography. These data strongly indicate that PVH might be caused by decreased cerebral blood flow.

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

    PubMed

    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

  10. 15O PET Measurement of Blood Flow and Oxygen Consumption in Cold-Activated Human Brown Fat

    PubMed Central

    Muzik, Otto; Mangner, Thomas J.; Leonard, William R.; Kumar, Ajay; Janisse, James; Granneman, James G.

    2013-01-01

    Although it has been believed that brown adipose tissue (BAT) depots disappear shortly after the perinatal period in humans, PET imaging using the glucose analog 18F-FDG has shown unequivocally the existence of functional BAT in adult humans, suggesting that many humans retain some functional BAT past infancy. The objective of this study was to determine to what extent BAT thermogenesis is activated in adults during cold stress and to establish the relationship between BAT oxidative metabolism and 18F-FDG tracer uptake. Methods Twenty-five healthy adults (15 women and 10 men; mean age ± SD, 30 ± 7 y) underwent triple-oxygen scans (H215O, C15O, and 15O2) as well as measurements of daily energy expenditure (DEE; kcal/d) both at rest and after exposure to mild cold (15.5°C [60°F]) using indirect calorimetry. The subjects were divided into 2 groups (high BAT and low BAT) based on the presence or absence of 18F-FDG tracer uptake (standardized uptake value [SUV] > 2) in cervical–supraclavicular BAT. Blood flow and oxygen extraction fraction (OEF) were calculated from dynamic PET scans at the location of BAT, muscle, and white adipose tissue. Regional blood oxygen saturation was determined by near-infrared spectroscopy. The total energy expenditure during rest and mild cold stress was measured by indirect calorimetry. Tissue-level metabolic rate of oxygen (MRO2) in BAT was determined and used to calculate the contribution of activated BAT to DEE. Results The mass of activated BAT was 59.1 ± 17.5 g (range, 32–85 g) in the high-BAT group (8 women and 1 man; mean age, 29.6 ± 5.5 y) and 2.2 ± 3.6 g (range, 0–9.3 g) in the low-BAT group (9 men and 7 women; mean age, 31.4 ± 10 y). Corresponding maximal SUVs were significantly higher in the high-BAT group than in the low-BAT group (10.7 ± 3.9 vs. 2.1 ± 0.7, P = 0.01). Blood flow values were significantly higher in the high-BAT group than in the low-BAT group for BAT (12.9 ± 4.1 vs. 5.9 ± 2.2 mL/100 g/min, P = 0

  11. Assessment of blood flow with 68Ga-DOTA PET in experimental inflammation: a validation study using 15O-water

    PubMed Central

    Autio, Anu; Saraste, Antti; Kudomi, Nobuyuki; Saanijoki, Tiina; Johansson, Jarkko; Liljenbäck, Heidi; Tarkia, Miikka; Oikonen, Vesa; Sipilä, Hannu T; Roivainen, Anne

    2014-01-01

    Increased blood flow and vascular permeability are key events in inflammation. Based on the fact that Gadolinium-1,4,7,10-tetraazacyclododecane-N,N‘,N‘‘,N‘‘‘-tetraacetic acid (Gd-DOTA) is commonly used in magnetic resonance (MR) imaging of blood flow (perfusion), we evaluated the feasibility of its Gallium-68 labeled DOTA analog (68Ga-DOTA) for positron emission tomography (PET) imaging of blood flow in experimental inflammation. Adult, male Sprague-Dawley rats with turpentine oil induced sterile skin/muscle inflammation were anesthetized with isoflurane, and imaged under rest and adenosine-induced hyperemia by means of dynamic 2-min Oxygen-15 labeled water (H2 15O) and 30-min 68Ga-DOTA PET. For the quantification of PET data, regions of interest (ROIs) were defined in the focus of inflammation, healthy muscle, myocardium and heart left ventricle. Radioactivity concentration in the ROIs versus time after injection was determined for both tracers and blood flow was calculated using image-derived input. According to the H2 15O PET, blood flow was 0.69 ± 0.15 ml/min/g for inflammation and 0.15 ± 0.03 ml/min/g for muscle during rest. The blood flow remained unchanged during adenosine-induced hyperemia 0.67 ± 0.11 and 0.12 ± 0.03 ml/min/g for inflammation and muscle, respectively, indicating that adenosine has little effect on blood flow in peripheral tissues in rats. High focal uptake of 68Ga-DOTA was seen at the site of inflammation throughout the 30-min PET imaging. According to the 68Ga-DOTA PET, blood flow measured as the blood-to-tissue transport rate (K1) was 0.60 ± 0.07 ml/min/g for inflammation and 0.14 ± 0.06 ml/min/g for muscle during rest and 0.63 ± 0.08 ml/min/g for inflammation and 0.09 ± 0.04 ml/min/g for muscle during adenosine-induced hyperemia. The H2 15O-based blood flow and 68Ga-DOTA-based K1 values correlated well (r = 0.94, P < 0.0001). These results show that 68Ga-DOTA PET imaging is useful for the quantification of increased

  12. Assessment of blood flow with (68)Ga-DOTA PET in experimental inflammation: a validation study using (15)O-water.

    PubMed

    Autio, Anu; Saraste, Antti; Kudomi, Nobuyuki; Saanijoki, Tiina; Johansson, Jarkko; Liljenbäck, Heidi; Tarkia, Miikka; Oikonen, Vesa; Sipilä, Hannu T; Roivainen, Anne

    2014-01-01

    Increased blood flow and vascular permeability are key events in inflammation. Based on the fact that Gadolinium-1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid (Gd-DOTA) is commonly used in magnetic resonance (MR) imaging of blood flow (perfusion), we evaluated the feasibility of its Gallium-68 labeled DOTA analog ((68)Ga-DOTA) for positron emission tomography (PET) imaging of blood flow in experimental inflammation. Adult, male Sprague-Dawley rats with turpentine oil induced sterile skin/muscle inflammation were anesthetized with isoflurane, and imaged under rest and adenosine-induced hyperemia by means of dynamic 2-min Oxygen-15 labeled water (H2 (15)O) and 30-min (68)Ga-DOTA PET. For the quantification of PET data, regions of interest (ROIs) were defined in the focus of inflammation, healthy muscle, myocardium and heart left ventricle. Radioactivity concentration in the ROIs versus time after injection was determined for both tracers and blood flow was calculated using image-derived input. According to the H2 (15)O PET, blood flow was 0.69 ± 0.15 ml/min/g for inflammation and 0.15 ± 0.03 ml/min/g for muscle during rest. The blood flow remained unchanged during adenosine-induced hyperemia 0.67 ± 0.11 and 0.12 ± 0.03 ml/min/g for inflammation and muscle, respectively, indicating that adenosine has little effect on blood flow in peripheral tissues in rats. High focal uptake of (68)Ga-DOTA was seen at the site of inflammation throughout the 30-min PET imaging. According to the (68)Ga-DOTA PET, blood flow measured as the blood-to-tissue transport rate (K1) was 0.60 ± 0.07 ml/min/g for inflammation and 0.14 ± 0.06 ml/min/g for muscle during rest and 0.63 ± 0.08 ml/min/g for inflammation and 0.09 ± 0.04 ml/min/g for muscle during adenosine-induced hyperemia. The H2 (15)O-based blood flow and (68)Ga-DOTA-based K1 values correlated well (r = 0.94, P < 0.0001). These results show that (68)Ga-DOTA PET imaging is useful for the quantification of

  13. Rapid quantitative CBF and CMRO2 measurements from a single PET scan with sequential administration of dual 15O-labeled tracers

    PubMed Central

    Kudomi, Nobuyuki; Hirano, Yoshiyuki; Koshino, Kazuhiro; Hayashi, Takuya; Watabe, Hiroshi; Fukushima, Kazuhito; Moriwaki, Hiroshi; Teramoto, Noboru; Iihara, Koji; Iida, Hidehiro

    2013-01-01

    Positron emission tomography (PET) with 15O tracers provides essential information in patients with cerebral vascular disorders, such as cerebral blood flow (CBF), oxygen extraction fraction (OEF), and metabolic rate of oxygen (CMRO2). However, most of techniques require an additional C15O scan for compensating cerebral blood volume (CBV). We aimed to establish a technique to calculate all functional images only from a single dynamic PET scan, without losing accuracy or statistical certainties. The technique was an extension of previous dual-tracer autoradiography (DARG) approach, but based on the basis function method (DBFM), thus estimating all functional parametric images from a single session of dynamic scan acquired during the sequential administration of H215O and 15O2. Validity was tested on six monkeys by comparing global OEF by PET with those by arteriovenous blood sampling, and tested feasibility on young healthy subjects. The mean DBFM-derived global OEF was 0.57±0.06 in monkeys, in an agreement with that by the arteriovenous method (0.54±0.06). Image quality was similar and no significant differences were seen from DARG; 3.57%±6.44% and 3.84%±3.42% for CBF, and −2.79%±11.2% and −6.68%±10.5% for CMRO2. A simulation study demonstrated similar error propagation between DBFM and DARG. The DBFM method enables accurate assessment of CBF and CMRO2 without additional CBV scan within significantly shortened examination period, in clinical settings. PMID:23232945

  14. Temporal alignment of tissue and arterial data and selection of integration start times for the H[sub 2] [sup 15]O autoradiographic CBF model in PET

    SciTech Connect

    Muzic, R.F. Jr. . Dept. of Biomedical Engineering); Nelson, A.D.; Miraldi, F. . Div. of Nuclear Medicine)

    1993-09-01

    A technique has been developed and tested that provides an automated method of temporally aligning the PET tissue activity curve with the arterial activity curve for quantification of cerebral blood flow using the H[sub 2] [sup 15]O autoradiographic model. This technique not only determines the relative time delay between the two curves, but also provides the start time of integration. Variability in computing global cerebral blood flow using this technique is shown to be less than that obtained by trained observers manually selecting parameters and at least as good as that obtained by using another automated alignment technique.

  15. Quantitative PET imaging with the 3T MR-BrainPET

    NASA Astrophysics Data System (ADS)

    Weirich, C.; Scheins, J.; Lohmann, P.; Tellmann, L.; Byars, L.; Michel, C.; Rota Kops, E.; Brenner, D.; Herzog, H.; Shah, N. J.

    2013-02-01

    The new hybrid imaging technology of MR-PET allows for simultaneous acquisition of versatile MRI contrasts and the quantitative metabolic imaging with PET. In order to achieve the quantification of PET images with minimal residual error the application of several corrections is crucial. In this work we present our results on quantification with the 3T MR BrainPET scanner.

  16. Relative 11C-PiB Delivery as a Proxy of Relative CBF: Quantitative Evaluation Using Single-Session 15O-Water and 11C-PiB PET

    PubMed Central

    Chen, Yin J.; Rosario, Bedda L.; Mowrey, Wenzhu; Laymon, Charles M.; Lu, Xueling; Lopez, Oscar L.; Klunk, William E.; Lopresti, Brian J.; Mathis, Chester A.; Price, Julie C.

    2016-01-01

    The primary goal of this study was to assess the suitability of 11C-Pittsburgh compound B (11C-PiB) blood–brain barrier delivery (K1) and relative delivery (R1) parameters as surrogate indices of cerebral blood flow (CBF), with a secondary goal of directly examining the extent to which simplified uptake measures of 11C-PiB retention (amyloid-β load) may be influenced by CBF, in a cohort of controls and patients with mild cognitive impairment (MCI) and Alzheimer disease (AD). Methods Nineteen participants (6 controls, 5 AD, 8 MCI) underwent MR imaging, 15O-water PET, and 11C-PiB PET in a single session. Fourteen regions of interest (including cerebellar reference region) were defined on MR imaging and applied to dynamic coregistered PET to generate time–activity curves. Multiple analysis approaches provided regional 15O-water and 11C-PiB measures of delivery and 11C-PiB retention that included compartmental modeling distribution volume ratio (DVR), arterial- and reference-based Logan DVR, simplified reference tissue modeling 2 (SRTM2) DVR, and standardized uptake value ratios. Spearman correlation was performed among delivery measures (i.e., 15O-water K1 and 11C-PiB K1, relative K1 normalized to cerebellum [Rel-K1-Water and Rel-K1-PiB], and 11C-PiB SRTM2-R1) and between delivery measures and 11C-PiB retention, using the Bonferroni method for multiple-comparison correction. Results Primary analysis showed positive correlations (ρ ≈0.2–0.5) between 15O-water K1 and 11C-PiB K1 that did not survive Bonferroni adjustment. Significant positive correlations were found between Rel-K1-Water and Rel-K1-PiB and between Rel-K1-Water and 11C-PiB SRTM2-R1 (ρ ≈0.5–0.8, P < 0.0036) across primary cortical regions. Secondary analysis showed few significant correlations between 11C-PiB retention and relative 11C-PiB delivery measures (but not 15O-water delivery measures) in primary cortical areas that arose only after accounting for cerebrospinal fluid dilution

  17. Assessment of coronary flow reserve using a combination of planar first-pass angiography and myocardial SPECT: Comparison with myocardial (15)O-water PET.

    PubMed

    Nose, Naoko; Fukushima, Kazuhito; Lapa, Constantin; Werner, Rudolf A; Javadi, Mehrbod Som; Taki, Junichi; Higuchi, Takahiro

    2016-11-01

    Coronary flow reserve (CFR), defined as the ratio of maximum coronary flow increase from baseline resting blood flow, is one of the most sensitive parameters to detect early signs of coronary arteriosclerosis at the microvascular level. Myocardial perfusion PET is a well-established technology for CFR measurement, however, availability is still limited. The aim of this study is to introduce and validate myocardial flow reserve measurement by myocardial perfusion SPECT. Myocardial perfusion SPECT at rest and ATP stress (0.16mg/Kg/min) was performed in 10 patients with known coronary artery disease. Immediately after the injection of Tc-99m sestamibi (MIBI), left ventricular (LV) dynamic planar angiographic data were obtained for 90s. Coronary flow reserve index as measured by MIBI SPECT (CFRMIBI) was calculated as follows: CFRMIBI=CmsSbmb/CmbSbms, where subscripts b, s, Cm, and Sbm indicate baseline, during stress, myocardial counts with MIBI SPECT, and integral of LV counts with first pass angiography, respectively. Additionally, standard stress/rest (15)O-water PET to estimate CFR was performed in all patients as standard of reference. CFRMIBI increased in conjunction with CFR, but underestimated blood flow at high flow rates. The relationship between CFRMIBI (Y) and CFRPET (X) was well fitted as follows: Y=1.40x(1-exp(1.79/x)) (r=0.84). The index of CFRMIBI reflects the CFR by (15)O-water PET but underestimates flow at high flows, maybe as a reflection of pharmacokinetic limitations of MIBI. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  18. Development of brain PET using GAPD arrays.

    PubMed

    Jung, Jin Ho; Choi, Yong; Hong, Key Jo; Kang, Jihoon; Hu, Wei; Lim, Hyun Keong; Huh, Yoonsuk; Kim, Sangsu; Jung, Jiwoong; Kim, Kyu Bom

    2012-03-01

    In recent times, there has been great interest in the use of Geiger-mode avalanche photodiodes (GAPDs) as scintillator readout in positron emission tomography (PET) detectors because of their advantages, such as high gain, compact size, low power consumption, and magnetic field insensitivity. The purpose of this study was to develop a novel PET system based on GAPD arrays for brain imaging. The PET consisted of 72 detector modules arranged in a ring of 330 mm diameter. Each PET module was composed of a 4 × 4 matrix of 3 × 3 × 20 mm(3) cerium-doped lutetium yttrium orthosilicate (LYSO) crystals coupled with a 4 × 4 array three-side tileable GAPD. The signals from each PET module were fed into preamplifiers using a 3 m long flat cable and then sent to a position decoder circuit (PDC), which output a digital address and an analog pulse of the interacted channel among 64 preamplifier signals transmitted from four PET detector modules. The PDC outputs were fed into field programmable gate array (FPGA)-embedded data acquisition (DAQ) boards. The analog signal was then digitized, and arrival time and energy of the signal were calculated and stored. The energy and coincidence timing resolutions measured for 511 keV gamma rays were 18.4 ± 3.1% and 2.6 ns, respectively. The transaxial spatial resolution and sensitivity in the center of field of view (FOV) were 3.1 mm and 0.32% cps/Bq, respectively. The rods down to a diameter of 2.5 mm were resolved in a hot-rod phantom image, and activity distribution patterns between the white and gray matters in the Hoffman brain phantom were well imaged. Experimental results indicate that a PET system can be developed using GAPD arrays and the GAPD-based PET system can provide high-quality PET imaging.

  19. Brain PET in the diagnosis of Alzheimer's disease.

    PubMed

    Marcus, Charles; Mena, Esther; Subramaniam, Rathan M

    2014-10-01

    The aim of this article was to review the current role of brain PET in the diagnosis of Alzheimer dementia. The characteristic patterns of glucose metabolism on brain FDG-PET can help in differentiating Alzheimer's disease from other causes of dementia such as frontotemporal dementia and dementia of Lewy body. Amyloid brain PET may exclude significant amyloid deposition and thus Alzheimer's disease in appropriate clinical setting. FDG-PET and amyloid PET imaging are valuable in the assessment of patients with Alzheimer's disease.

  20. Brain PET in the Diagnosis of Alzheimer’s Disease

    PubMed Central

    Marcus, Charles; Mena, Esther; Subramaniam, Rathan M.

    2015-01-01

    Objectives The aim of this article was to review the current role of brain PET in the diagnosis of Alzheimer dementia. The characteristic patterns of glucose metabolism on brain FDG-PET can help in differentiating Alzheimer’s disease from other causes of dementia such as frontotemporal dementia and dementia of Lewy body. Amyloid brain PET may exclude significant amyloid deposition and thus Alzheimer’s disease in appropriate clinical setting. Conclusions FDG-PET and amyloid PET imaging are valuable in the assessment of patients with Alzheimer’s disease. PMID:25199063

  1. Abnormal resting state corticolimbic blood flow in depressed unmedicated patients with major depression: a (15)O-H(2)O PET study.

    PubMed

    Monkul, E Serap; Silva, Leandro A P; Narayana, Shalini; Peluso, Marco A M; Zamarripa, Frank; Nery, Fabiano G; Najt, Pablo; Li, John; Lancaster, Jack L; Fox, Peter T; Lafer, Beny; Soares, Jair C

    2012-02-01

    We investigated the differences in the resting state corticolimbic blood flow between 20 unmedicated depressed patients and 21 healthy comparisons. Resting state cerebral blood flow (CBF) was measured with H(2)(15)O PET. Anatomical MRI scans were performed on an Elscint 1.9 T Prestige system for PET-MRI coregistration. Significant changes in cerebral blood flow indicating neural activity were detected using an ROI-free image subtraction strategy. In addition, the resting blood flow in patients was correlated with the severity of depression as measured by HAM-D scores. Depressed patients showed decreases in blood flow in right anterior cingulate (Brodmann areas 24 and 32) and increased blood flow in left and right posterior cingulate (Brodmann areas 23, 29, 30), left parahippocampal gyrus (Brodmann area 36), and right caudate compared with healthy volunteers. The severity of depression was inversely correlated with the left middle and inferior frontal gyri (Brodmann areas 9 and 47) and right medial frontal gyrus (Brodmann area 10) and right anterior cingulate (Brodmann areas 24, 32) blood flow, and directly correlated with the right thalamus blood flow. These findings support previous reports of abnormalities in the resting state blood flow in the limbic-frontal structures in depressed patients compared to healthy volunteers. Copyright © 2011 Wiley Periodicals, Inc.

  2. Neural correlates of strategic processes underlying episodic memory in women with major depression: A 15O-PET study.

    PubMed

    Ottowitz, William E; Deckersbach, Thilo; Savage, Cary R; Lindquist, Martin A; Dougherty, Darin D

    2010-01-01

    To evaluate the functional integrity of brain regions underlying strategic mnemonic processing in patients with major depressive disorder, the authors administered a modified version of the California Verbal Learning Test to depressed patients during presentation of lists of unrelated words and, conversely, during presentation of lists of related words with and without orientation regarding the relatedness of the words (eight healthy females, IQ=122, and eight depressed females, IQ=107). Brain function evaluated across all three conditions showed that patients with major depressive disorder revealed activation of the right anterior cingulate cortex, left ventrolateral prefrontal cortex, both hippocampi, and the left orbitofrontal cortex. Further analysis showed that patients with major depressive disorder had greater activation of the right anterior cingulate cortex during semantic organization and the right ventrolateral prefrontal cortex during strategy initiation.

  3. Monte Carlo estimation of scatter effects on quantitative myocardial blood flow and perfusable tissue fraction using 3D-PET and 15O-water

    NASA Astrophysics Data System (ADS)

    Hirano, Yoshiyuki; Koshino, Kazuhiro; Watabe, Hiroshi; Fukushima, Kazuhito; Iida, Hidehiro

    2012-11-01

    In clinical cardiac positron emission tomography using 15O-water, significant tracer accumulation is observed not only in the heart but also in the liver and lung, which are partially outside the field-of-view. In this work, we investigated the effects of scatter on quantitative myocardium blood flow (MBF) and perfusable tissue fraction (PTF) by a precise Monte Carlo simulation (Geant4) and a numerical human model. We assigned activities to the heart, liver, and lung of the human model with varying ratios of organ activities according to an experimental time activity curve and created dynamic sinograms. The sinogram data were reconstructed by filtered backprojection. By comparing a scatter-corrected image (SC) with a true image (TRUE), we evaluated the accuracy of the scatter correction. TRUE was reconstructed using a scatter-eliminated sinogram, which can be obtained only in simulations. A scatter-uncorrected image (W/O SC) and an attenuation-uncorrected image (W/O AC) were also constructed. Finally, we calculated MBF and PTF with a single tissue-compartment model for four types of images. As a result, scatter was corrected accurately, and MBFs derived from all types of images were consistent with the MBF obtained from TRUE. Meanwhile, the PTF of only the SC was in agreement with the PTF of TRUE. From the simulation results, we concluded that quantitative MBF is less affected by scatter and absorption in 3D-PET using 15O-water. However, scatter correction is essential for accurate PTF.

  4. Comparison of microsphere-equivalent blood flow (15O-water PET) and relative perfusion (99mTc-tetrofosmin SPECT) in myocardium showing metabolism-perfusion mismatch.

    PubMed

    Schaefer, Wolfgang M; Nowak, Bernd; Kaiser, Hans-Juergen; Koch, Karl-Christian; Block, Stephan; vom Dahl, Juergen; Buell, Udalrich

    2003-01-01

    Myocardial perfusion imaging with (99m)Tc-tetrofosmin is based on the assumption of a linear correlation between myocardial blood flow (MBF) and tracer uptake. However, it is known that (99m)Tc-tetrofosmin uptake is directly related to energy-dependent transport processes, such as Na(+)/H(+) ion channel activity, as well as cellular and mitochondrial membrane potentials. Therefore, cellular alterations that affect these energy-dependent transport processes ought to influence (99m)Tc-tetrofosmin uptake independently of blood flow. Because metabolism ((18)F-FDG)-perfusion ((99m)Tc-tetrofosmin) mismatch myocardium (MPMM) reflects impaired but viable myocardium showing cellular alterations, MPMM was chosen to quantify the blood flow-independent effect of cellular alterations on (99m)Tc-tetrofosmin uptake. Therefore, we compared microsphere-equivalent MBF (MBF_micr; (15)O-water PET) and (99m)Tc-tetrofosmin uptake in MPMM and in "normal" myocardium. Forty-two patients with severe coronary artery disease, referred for myocardial viability diagnostics, were examined using (18)F-FDG PET and (99m)Tc-tetrofosmin perfusion SPECT. Relative (18)F-FDG and (99m)Tc-tetrofosmin uptake values were calculated using 18 segments per patient. Normal myocardium and MPMM myocardium were classified using a previously validated (99m)Tc-tetrofosmin SPECT/(18)F-FDG PET score. In addition, (15)O-water PET was performed to assess kinetic-modeled MBF (MBF_kin), the water-perfusable tissue fraction (PTF), and the resulting MBF_micr (MBF_kin x PTF), which is comparable to tracer uptake values. (99m)Tc-tetrofosmin uptake and MBF_micr values were calculated for all normal and MPMM segments and averaged within their respective classifications. Mean relative (99m)Tc-tetrofosmin uptake was 86% +/- 1% in normal myocardium and 56% +/- 1% in MPMM, showing a significant difference (P < 0.001), as was expected from the classification. Contrary to these findings, mean MBF_micr in MPMM myocardium was 0

  5. Development of PET/MRI with insertable PET for simultaneous PET and MR imaging of human brain

    SciTech Connect

    Jung, Jin Ho; Choi, Yong Jung, Jiwoong; Kim, Sangsu; Lim, Hyun Keong; Im, Ki Chun; Oh, Chang Hyun; Park, Hyun-wook; Kim, Kyung Min; Kim, Jong Guk

    2015-05-15

    Purpose: The purpose of this study was to develop a dual-modality positron emission tomography (PET)/magnetic resonance imaging (MRI) with insertable PET for simultaneous PET and MR imaging of the human brain. Methods: The PET detector block was composed of a 4 × 4 matrix of detector modules, each consisting of a 4 × 4 array LYSO coupled to a 4 × 4 Geiger-mode avalanche photodiode (GAPD) array. The PET insert consisted of 18 detector blocks, circularly mounted on a custom-made plastic base to form a ring with an inner diameter of 390 mm and axial length of 60 mm. The PET gantry was shielded with gold-plated conductive fabric tapes with a thickness of 0.1 mm. The charge signals of PET detector transferred via 4 m long flat cables were fed into the position decoder circuit. The flat cables were shielded with a mesh-type aluminum sheet with a thickness of 0.24 mm. The position decoder circuit and field programmable gate array-embedded DAQ modules were enclosed in an aluminum box with a thickness of 10 mm and located at the rear of the MR bore inside the MRI room. A 3-T human MRI system with a Larmor frequency of 123.7 MHz and inner bore diameter of 60 cm was used as the PET/MRI hybrid system. A custom-made radio frequency (RF) coil with an inner diameter of 25 cm was fabricated. The PET was positioned between gradient and the RF coils. PET performance was measured outside and inside the MRI scanner using echo planar imaging, spin echo, turbo spin echo, and gradient echo sequences. MRI performance was also evaluated with and without the PET insert. The stability of the newly developed PET insert was evaluated and simultaneous PET and MR images of a brain phantom were acquired. Results: No significant degradation of the PET performance caused by MR was observed when the PET was operated using various MR imaging sequences. The signal-to-noise ratio of MR images was slightly degraded due to the PET insert installed inside the MR bore while the homogeneity was

  6. Development of PET/MRI with insertable PET for simultaneous PET and MR imaging of human brain.

    PubMed

    Jung, Jin Ho; Choi, Yong; Jung, Jiwoong; Kim, Sangsu; Lim, Hyun Keong; Im, Ki Chun; Oh, Chang Hyun; Park, Hyun-wook; Kim, Kyung Min; Kim, Jong Guk

    2015-05-01

    The purpose of this study was to develop a dual-modality positron emission tomography (PET)/magnetic resonance imaging (MRI) with insertable PET for simultaneous PET and MR imaging of the human brain. The PET detector block was composed of a 4 × 4 matrix of detector modules, each consisting of a 4 × 4 array LYSO coupled to a 4 × 4 Geiger-mode avalanche photodiode (GAPD) array. The PET insert consisted of 18 detector blocks, circularly mounted on a custom-made plastic base to form a ring with an inner diameter of 390 mm and axial length of 60 mm. The PET gantry was shielded with gold-plated conductive fabric tapes with a thickness of 0.1 mm. The charge signals of PET detector transferred via 4 m long flat cables were fed into the position decoder circuit. The flat cables were shielded with a mesh-type aluminum sheet with a thickness of 0.24 mm. The position decoder circuit and field programmable gate array-embedded DAQ modules were enclosed in an aluminum box with a thickness of 10 mm and located at the rear of the MR bore inside the MRI room. A 3-T human MRI system with a Larmor frequency of 123.7 MHz and inner bore diameter of 60 cm was used as the PET/MRI hybrid system. A custom-made radio frequency (RF) coil with an inner diameter of 25 cm was fabricated. The PET was positioned between gradient and the RF coils. PET performance was measured outside and inside the MRI scanner using echo planar imaging, spin echo, turbo spin echo, and gradient echo sequences. MRI performance was also evaluated with and without the PET insert. The stability of the newly developed PET insert was evaluated and simultaneous PET and MR images of a brain phantom were acquired. No significant degradation of the PET performance caused by MR was observed when the PET was operated using various MR imaging sequences. The signal-to-noise ratio of MR images was slightly degraded due to the PET insert installed inside the MR bore while the homogeneity was maintained. The change of gain of

  7. The development, past achievements, and future directions of brain PET

    PubMed Central

    Jones, Terry; Rabiner, Eugenii A

    2012-01-01

    The early developments of brain positron emission tomography (PET), including the methodological advances that have driven progress, are outlined. The considerable past achievements of brain PET have been summarized in collaboration with contributing experts in specific clinical applications including cerebrovascular disease, movement disorders, dementia, epilepsy, schizophrenia, addiction, depression and anxiety, brain tumors, drug development, and the normal healthy brain. Despite a history of improving methodology and considerable achievements, brain PET research activity is not growing and appears to have diminished. Assessments of the reasons for decline are presented and strategies proposed for reinvigorating brain PET research. Central to this is widening the access to advanced PET procedures through the introduction of lower cost cyclotron and radiochemistry technologies. The support and expertize of the existing major PET centers, and the recruitment of new biologists, bio-mathematicians and chemists to the field would be important for such a revival. New future applications need to be identified, the scope of targets imaged broadened, and the developed expertize exploited in other areas of medical research. Such reinvigoration of the field would enable PET to continue making significant contributions to advance the understanding of the normal and diseased brain and support the development of advanced treatments. PMID:22434067

  8. Metabolic brain PET pattern underlying hyperkinetic seizures.

    PubMed

    Guedj, Eric; McGonigal, Aileen; Vaugier, Lisa; Mundler, Olivier; Bartolomei, Fabrice

    2012-09-01

    This study aims to contribute to the identification of selective brain regions involved in hyperkinetic behaviors. We studied the whole-brain voxel-based interictal metabolic 18FDG-PET pattern of 23 patients with hyperkinetic seizures, in comparison with both 15 healthy subjects similar for age and gender, and 23 patients without hyperkinetic seizures. Patients were in particular similar for the localization of the epileptogenic zone, this having been defined using stereoelectroencephalography (SEEG) when clinically indicated (15/23 patients with hyperkinetic seizures and 13/23 patients without hyperkinetic seizures). Using conjunction voxel-based analysis, patients with hyperkinetic seizures exhibited significant hypometabolism within bilateral midbrain and the right caudate head, in comparison both to healthy subjects (p<0.05, FDR-corrected for the voxel) and to patients without hyperkinetic seizures (p<0.0167, uncorrected for the voxel). Findings were secondarily confirmed separately in each subgroup of patients with frontal, temporal or posterior epilepsy. These findings argue for a specific subcortical metabolic impairment in patients with hyperkinetic seizures, within brain structures supposed to be involved in the generation of primitive motor programs.

  9. A potential role for the midbrain in integrating fat-free mass determined energy needs: An H2 (15) O PET study.

    PubMed

    Weise, Christopher M; Thiyyagura, Pradeep; Reiman, Eric M; Chen, Kewei; Krakoff, Jonathan

    2015-06-01

    Little is known on how sensing of energy needs is centrally represented, integrated, and translated into the behavioral aspects of energy homeostasis. Fat free mass (FFM) is the major determinant of energy expenditure. We investigated how interindividual variances in FFM relate to neuronal activity in humans. Healthy adults (n = 64, 21F/43M; age 31.3 ± 9.1y; percentage of body fat [PFAT] 25.6 ± 10.7%; BMI 30.4 ± 9) underwent a 36h fast and subsequent H(2) (15) O positron emission tomographic (PET) measurement of regional cerebral blood flow (rCBF). Multiple variable regression analysis revealed significant associations of FFM with rCBF within the midbrain [including parts of the periaqueductal gray (PAG), ventral tegmental area (VTA), thalamic and hypothalamic regions], the bilateral parahippocampal region, left anterior cingulate, left insular cortex, right cerebellum, and distinct regions within the temporal and occipital cortex. In contrast, no significant associations were found for fat mass (FM). We investigated the potential functional-anatomical link between FFM and central regulation of food intake by performing a conjunction analysis of FFM and the perceived hunger feelings. This showed a significant overlap within the midbrain PAG. Mediation analysis demonstrated a significant indirect effect of FFM on hunger with PAG rCBF as mediator. Most regions we found to be associated with FFM form part in ascending homeostatic pathways and cortical circuitries implicated in the regulation of basic bodily functions indicating a potential role of these central networks in the integration of FFM determined energy needs. © 2015 Wiley Periodicals, Inc.

  10. Molecular imaging of brain tumors with 18F-DOPA PET and PET/CT.

    PubMed

    Calabria, Ferdinando; Chiaravalloti, Agostino; Di Pietro, Barbara; Grasso, Cristina; Schillaci, Orazio

    2012-06-01

    The objective of this study was to give an overview of the potential clinical utility of [18F]-L-dihydroxyphenylalanine (18F-DOPA) PET and PET/CT for imaging of brain tumors. Review articles and reference lists were used to supplement the search findings. 18F-DOPA has been investigated as a PET tracer for primary brain tumors, metastases of somatic cancer, and evaluation of relapse of pathology in patients with brain tumor after surgery and/or radiotherapy on the basis of enhanced cell proliferation. Available studies have provided encouraging preliminary results for diagnosis of brain tumors and relapse after surgery/radiotherapy. In the brain, excellent discrimination between tumor and normal tissue can be achieved because of the low physiological uptake of 18F-DOPA and the high ratio between tumor and normal hemispheric tissue. Information on evaluation of brain metastases is limited but encouraging. PET and PET/CT with 18F-DOPA are useful in diagnosing primary brain tumors and should be recommended in the diagnosis of relapse of disease after surgical treatment and/or radiotherapy. Semiquantitative analysis could improve diagnosis while correlative imaging with MRI is essential. Limits are due to low knowledge of potential pitfalls.

  11. A prototype MR insertable brain PET using tileable GAPD arrays.

    PubMed

    Hong, Key Jo; Choi, Yong; Jung, Jin Ho; Kang, Jihoon; Hu, Wei; Lim, Hyun Keong; Huh, Yoonsuk; Kim, Sangsu; Jung, Ji Woong; Kim, Kyu Bom; Song, Myung Sung; Park, Hyun-Wook

    2013-04-01

    The aim of this study was to develop a prototype magnetic resonance (MR)-compatible positron emission tomography (PET) that can be inserted into a MR imager and that allows simultaneous PET and MR imaging of the human brain. This paper reports the initial results of the authors' prototype brain PET system operating within a 3-T magnetic resonance imaging (MRI) system using newly developed Geiger-mode avalanche photodiode (GAPD)-based PET detectors, long flexible flat cables, position decoder circuit with high multiplexing ratio, and digital signal processing with field programmable gate array-based analog to digital converter boards. A brain PET with 72 detector modules arranged in a ring was constructed and mounted in a 3-T MRI. Each PET module was composed of cerium-doped lutetium yttrium orthosilicate (LYSO) crystals coupled to a tileable GAPD. The GAPD output charge signals were transferred to preamplifiers using 3 m long flat cables. The LYSO and GAPD were located inside the MR bore and all electronics were positioned outside the MR bore. The PET detector performance was investigated both outside and inside the MRI, and MR image quality was evaluated with and without the PET system. The performance of the PET detector when operated inside the MRI during MR image acquisition showed no significant change in energy resolution and count rates, except for a slight degradation in timing resolution with an increase from 4.2 to 4.6 ns. Simultaneous PET/MR images of a hot-rod and Hoffman brain phantom were acquired in a 3-T MRI. Rods down to a diameter of 3.5 mm were resolved in the hot-rod PET image. The activity distribution patterns between the white and gray matter in the Hoffman brain phantom were well imaged. The hot-rod and Hoffman brain phantoms on the simultaneously acquired MR images obtained with standard sequences were observed without any noticeable artifacts, although MR image quality requires some improvement. These results demonstrate that the

  12. Study of the production yields of 18F, 11C, 13N and 15O positron emitters from plasma-laser proton sources at ELI-Beamlines for labeling of PET radiopharmaceuticals

    NASA Astrophysics Data System (ADS)

    Amato, Ernesto; Italiano, Antonio; Margarone, Daniele; Pagano, Benedetta; Baldari, Sergio; Korn, Georg

    2016-03-01

    The development of novel compact PET radionuclide production systems is of great interest to promote the diffusion of PET diagnostics, especially in view of the continuous development of microfluidics labeling approaches. We studied the feasibility to produce clinically-relevant amounts of PET isotopes by means of laser-accelerated proton sources such that expected at the ELI-Beamlines facility. 18F, 11C, 13N and 15O production yields were calculated through the TALYS software, by taking into account the broad proton spectra expected. With the hypothesized proton fluencies, clinically-relevant amounts of radionuclides can be obtained, suitable to prepare single doses of 18F-, 11C- and 13N-labeled radiopharmaceuticals exploiting fast and efficient microfluidic labeling systems.

  13. Brain blood flow measured with intravenous H/sub 2/ /sup 15/O. II. Implementation and validation

    SciTech Connect

    Raichle, M.E.; Martin, W.R.W.; Herscovitch, P.; Mintun, M.A.; Markham, J.

    1983-09-01

    The well-known tissue autoradiographic technique for the measurement of regional cerebral blood flow (CBF), originally proposed by Kety and his colleagues has been adapted for the measurement of CBF in human subjects using positron emission tomography (PET) and intravenously administered oxygen-15-labeled water. This report describes the steps necessary for the implementation of this PET/autoradiographic technique. In order to establish the accuracy of the method, we measured CBF with intravenously administered oxygen-15-labeled water and PET in anesthetized adult baboons and compared the results with blood flow measured by a standard tracer technique that uses residue detection of a bolus of oxygen-15-labeled water injected into the internal carotid artery. The correlation between CBF measured with PET and the true CBF for the same cerebral hemisphere was excellent.

  14. PET radiopharmaceuticals for probing enzymes in the brain

    PubMed Central

    Holland, Jason P; Cumming, Paul; Vasdev, Neil

    2013-01-01

    Biologically important processes in normal brain function and brain disease involve the action of various protein-based receptors, ion channels, transporters and enzymes. The ability to interrogate the location, abundance and activity of these entities in vivo using non-invasive molecular imaging can provide unprecedented information about the spatio-temporal dynamics of brain function. Indeed, positron emission tomography (PET) imaging is transforming our understanding of the central nervous system and brain disease. Great emphasis has historically been placed on developing radioligands for the non-invasive detection of neuroreceptors. In contrast, relatively few enzymes have been amenable to examination by PET imaging procedures based upon trapping or accumulation of enzymatic products, because only a subset of enzymes have sufficient catalytic rate to produce measureable accumulation within the practical time-limit of PET recordings. However, high affinity inhibitors are now serving as tracers for enzymes, particularly for measuring the abundance of enzymes mediating intracellular signal transduction in the brain, which offer a rich diversity of potential targets for drug discovery. The purpose of this review is to summarize well-known radiotracers for brain enzymes, and draw attention to recent developments in PET radiotracers for imaging signal transduction pathways in the brain. The review is organized by target class and focuses on structural chemistry of the best-established radiotracers identified in each class. PMID:23638333

  15. Fourier-wavelet restoration in PET/CT brain studies

    NASA Astrophysics Data System (ADS)

    Knešaurek, Karin

    2012-10-01

    Our goal is to improve brain PET imaging through the application of a novel, hybrid Fourier-wavelet (WFT) restoration technique. The major limitation of PET studies is a relatively poor resolution in comparison with MRI and CT imaging and there is a need for improved PET imaging. A GE DLS PET/CT 16 slice system was used to acquire the studies. In order to create restoration filters the point source study was performed. The 6-fillable spheres and 3D Hoffman brain phantom studies were acquired and used to test and optimize the restoration approach. The patient data used in the study were acquired in a 3D PET mode, using the standard clinical protocol. Here, we have implemented Fourier-wavelet regularized restoration. In the Fourier domain, the inverse of modulation transfer function was multiplied by a Butterworth low-pass filter, order n=6 and cut-off frequency f=0.35 cycles/pixel. In addition, wavelet (Daubechies, order 2) noise suppression was applied by “hard threshold”. Hot spheres and 3D Hoffman brain studies showed that the restoration process not only improves resolution and contrast but also improves quantification in 3D PET/CT imaging. The average contrast increase was 19% and the quantification improved in the range 8-20% depending on sphere size. In the restored images, there was no significant increase in noise when compared with the original images. The clinical studies followed brain phantom findings, i.e., the restored images had better contrast and resolution properties, when compared with the original images. The results of the study demonstrate that the quality and quantification of 3D brain 18F FDG PET images can be significantly improved by Fourier-wavelet (WFT) restoration filtering.

  16. Prediction of standard-dose brain PET image by using MRI and low-dose brain [{sup 18}F]FDG PET images

    SciTech Connect

    Kang, Jiayin; Gao, Yaozong; Shi, Feng; Lalush, David S.; Lin, Weili; Shen, Dinggang

    2015-09-15

    Purpose: Positron emission tomography (PET) is a nuclear medical imaging technology that produces 3D images reflecting tissue metabolic activity in human body. PET has been widely used in various clinical applications, such as in diagnosis of brain disorders. High-quality PET images play an essential role in diagnosing brain diseases/disorders. In practice, in order to obtain high-quality PET images, a standard-dose radionuclide (tracer) needs to be used and injected into a living body. As a result, it will inevitably increase the patient’s exposure to radiation. One solution to solve this problem is predicting standard-dose PET images using low-dose PET images. As yet, no previous studies with this approach have been reported. Accordingly, in this paper, the authors propose a regression forest based framework for predicting a standard-dose brain [{sup 18}F]FDG PET image by using a low-dose brain [{sup 18}F]FDG PET image and its corresponding magnetic resonance imaging (MRI) image. Methods: The authors employ a regression forest for predicting the standard-dose brain [{sup 18}F]FDG PET image by low-dose brain [{sup 18}F]FDG PET and MRI images. Specifically, the proposed method consists of two main steps. First, based on the segmented brain tissues (i.e., cerebrospinal fluid, gray matter, and white matter) in the MRI image, the authors extract features for each patch in the brain image from both low-dose PET and MRI images to build tissue-specific models that can be used to initially predict standard-dose brain [{sup 18}F]FDG PET images. Second, an iterative refinement strategy, via estimating the predicted image difference, is used to further improve the prediction accuracy. Results: The authors evaluated their algorithm on a brain dataset, consisting of 11 subjects with MRI, low-dose PET, and standard-dose PET images, using leave-one-out cross-validations. The proposed algorithm gives promising results with well-estimated standard-dose brain [{sup 18}F]FDG PET

  17. [The advantages and limitations of brain function analyses by PET].

    PubMed

    Kato, M; Taniwaki, T; Kuwabara, Y

    2000-12-01

    PET has been proved to be a powerful tool for exploring the brain function. We discussed the advantages and limitations of PET for analyzing the brain function on the basis of our clinical and experimental experiences of functional imaging. A multimodality PET study measuring cerebral energy metabolism (CMRO2 and CMRglc), cerebral blood flow (CBF), oxygen extraction fraction (OEF) and neurotransmitter function (presynaptic and postsynaptic) opens up a closer insight into a precise pathophysiology of the brain dysfunction: In cerebral infarction, it reveals a state of "misery perfusion" in the acute stage, "luxury perfusion" in the intermediate stage, and proportionately decreased CBF and CMRO2 in the chronic stage. Neurotransmitter function may identify specifically a neuronal subgroup of dysfunction. Owing to the low temporal resolution of PET, a neuronal activity may propagate transsynaptically to remote areas during the period of scanning, resulting in an obscured primary site of the neuronal activity. Uncoupling between neuronal activities and cerebral energy metabolism/CBF may occur under a certain state of brain pathology, particularly after an acute destructive lesion, according to our experimental studies. Neurotransmitter function may reveal the effect of drugs on the brain function, and may be useful for developing a new method of drug therapy for brain diseases in the future.

  18. Alterations in CNS Activity Induced by Botulinum Toxin Treatment in Spasmodic Dysphonia: An H[subscript 2][superscript 15]O PET Study

    ERIC Educational Resources Information Center

    Ali, S. Omar; Thomassen, Michael; Schulz, Geralyn M.; Hosey, Lara A.; Varga, Mary; Ludlow, Christy L.; Braun, Allen R.

    2006-01-01

    Speech-related changes in regional cerebral blood flow (rCBF) were measured using H[subscript 2][superscript 15]O positron-emission tomography in 9 adults with adductor spasmodic dysphonia (ADSD) before and after botulinum toxin (BTX) injection and 10 age- and gender-matched volunteers without neurological disorders. Scans were acquired at rest…

  19. Alterations in CNS Activity Induced by Botulinum Toxin Treatment in Spasmodic Dysphonia: An H[subscript 2][superscript 15]O PET Study

    ERIC Educational Resources Information Center

    Ali, S. Omar; Thomassen, Michael; Schulz, Geralyn M.; Hosey, Lara A.; Varga, Mary; Ludlow, Christy L.; Braun, Allen R.

    2006-01-01

    Speech-related changes in regional cerebral blood flow (rCBF) were measured using H[subscript 2][superscript 15]O positron-emission tomography in 9 adults with adductor spasmodic dysphonia (ADSD) before and after botulinum toxin (BTX) injection and 10 age- and gender-matched volunteers without neurological disorders. Scans were acquired at rest…

  20. PET evaluation of the dopamine system of the human brain

    SciTech Connect

    Volkow, N.D.; Fowler, J.S.; Gatley, S. |

    1996-07-01

    Dopamine plays a pivotal role in the regulation and control of movement, motivation and cognition. It also is closely linked to reward, reinforcement and addiction. Abnormalities in brain dopamine are associated with many neurological and psychiatric disorders including Parkinson`s disease, schizophrenia and substance abuse. This close association between dopamine and neurological and psychiatric diseases and with substance abuse make it an important topic in research in the neurosciences and an important molecular target in drug development. PET enables the direct measurement of components of the dopamine system in the living human brain. It relies on radiotracers which label dopamine receptors, dopamine transporters, precursors of dopamine or compounds which have specificity for the enzymes which degrade dopamine. Additionally, by using tracers that provide information on regional brain metabolism or blood flow as well as neurochemically specific pharmacological interventions, PET can be used to assess the functional consequences of change in brain dopamine activity. PET dopamine measurements have been used to investigate the normal human brain and its involvement in psychiatric and neurological diseases. It has also been used in psychopharmacological research to investigate dopamine drugs used in the treatment of Parkinson`s disease and of schizophrenia as well as to investigate the effects of drugs of abuse on the dopamine system. Since various functional and neurochemical parameters can be studied in the same subject, PET enables investigation of the functional integrity of the dopamine system in the human brain and investigation of the interactions of dopamine with other neurotransmitters. This paper summarizes the different tracers and experimental strategies developed to evaluate the various elements of the dopamine system in the human brain with PET and their applications to clinical research. 254 refs., 7 figs., 3 tabs.

  1. Sensitivity of measurements of regional brain activation with oxygen-15-water and PET to time of stimulation and period of image reconstruction

    SciTech Connect

    Volkow, N.D.; Mullani, N.; Gould, L.K.; Adler, S.S.; Gatley, S.J. )

    1991-01-01

    Measurement of oxygen-15- (15O) water uptake with positron emission tomography (PET) is a sensitive technique to monitor regional brain activation secondary to stimulation paradigms. In order to investigate data acquisition times that show maximal changes in regional activation and to assess the optimal time for stimulus presentation, we investigated 10 controls with 15O-water and PET during baseline and stroboscopic light stimulation. Sequential scans were done varying the time of stimulus presentation. The images were reconstructed using three different periods of data acquisition: uptake phase (initial 30-35 sec), washout phase (40 sec following peak activity in brain), and total activity (3 min). The images reconstructed during the uptake phase showed the largest changes in occipital cortex from stimulation. Maximal changes in occipital cortex were obtained when the visual stimulus was maintained during the uptake phase only.

  2. Regional cerebral blood flow imaging: A quantitative comparison of technetium-99m-HMPAO SPECT with C15O2 PET

    SciTech Connect

    Gemmell, H.G.; Evans, N.T.; Besson, J.A.; Roeda, D.; Davidson, J.; Dodd, M.G.; Sharp, P.F.; Smith, F.W.; Crawford, J.R.; Newton, R.H. )

    1990-10-01

    The aim of this study was to compare technetium-99m-hexamethylpropyleneamineoxime ({sup 99m}Tc-HMPAO) single-photon emission computed tomography (SPECT) with regional cerebral blood flow (rCBF) imaging using positron emission tomography (PET). As investigation of dementia is likely to be one of the main uses of routine rCBF imaging, 18 demented patients were imaged with both techniques. The PET data were compared quantitatively with three versions of the SPECT data. These were, first, data normalized to the SPECT cerebellar uptake, second, data linearly corrected using the PET cerebellar value and, finally, data Lassen corrected for washout from the high flow areas. Both the linearly-corrected (r = 0.81) and the Lassen-corrected (r = 0.79) HMPAO SPECT data showed good correlation with the PET rCBF data. The relationship between the normalized HMPAO SPECT data and the PET data was nonlinear. It is not yet possible to obtain rCBF values in absolute units from HMPAO SPECT without knowledge of the true rCBF in one reference region for each patient.

  3. Compact and mobile high resolution PET brain imager

    DOEpatents

    Majewski, Stanislaw [Yorktown, VA; Proffitt, James [Newport News, VA

    2011-02-08

    A brain imager includes a compact ring-like static PET imager mounted in a helmet-like structure. When attached to a patient's head, the helmet-like brain imager maintains the relative head-to-imager geometry fixed through the whole imaging procedure. The brain imaging helmet contains radiation sensors and minimal front-end electronics. A flexible mechanical suspension/harness system supports the weight of the helmet thereby allowing for patient to have limited movements of the head during imaging scans. The compact ring-like PET imager enables very high resolution imaging of neurological brain functions, cancer, and effects of trauma using a rather simple mobile scanner with limited space needs for use and storage.

  4. Stereotactic PET atlas of the human brain: Aid for visual interpretation of functional brain images

    SciTech Connect

    Minoshima, S.; Koeppe, R.A.; Frey, A.; Ishihara, M.; Kuhl, D.E.

    1994-06-01

    In the routine analysis of functional brain images obtained by PET, subjective visual interpretation is often used for anatomic localization. To enhance the accuracy and consistency of the anatomic interpretation, a PET stereotactic atlas and localization approach was designed for functional brain images. The PET atlas was constructed from a high-resolution [{sup 18}F]fluorodeoxyglucose (FDG) image set of a normal volunteer (a 41-yr-ld woman). The image set was reoriented stereotactically, according to the intercommissural (anterior and posterior commissures) line and transformed to the standard stereotactic atlas coordinates. Cerebral structures were annotated on the transaxial planes using a proportional grid system and surface-rendered images. The stereotactic localization technique was applied to image sets from patients with Alzheimer`s disease, and areas of functional alteration were localized visually by referring to the PET atlas. Major brain structures were identified on both transaxial planes and surface-rendered images. In the stereotactic system, anatomic correspondence between the PET atlas and stereotactically reoriented individual image sets of patients with Alzheimer`s disease facilitated both indirect and direct localization of the cerebral structures. Because rapid stereotactic alignment methods for PET images are now available for routine use, the PET atlas will serve as an aid for visual interpretation of functional brain images in the stereotactic system. Widespread application of stereotactic localization may be used in functional brain images, not only in the research setting, but also in routine clinical situations. 41 refs., 3 figs.

  5. Hybrid PET/MR Imaging and Brain Connectivity

    PubMed Central

    Aiello, Marco; Cavaliere, Carlo; Salvatore, Marco

    2016-01-01

    In recent years, brain connectivity is gaining ever-increasing interest from the interdisciplinary research community. The study of brain connectivity is characterized by a multifaceted approach providing both structural and functional evidence of the relationship between cerebral regions at different scales. Although magnetic resonance (MR) is the most established imaging modality for investigating connectivity in vivo, the recent advent of hybrid positron emission tomography (PET)/MR scanners paved the way for more comprehensive investigation of brain organization and physiology. Due to the high sensitivity and biochemical specificity of radiotracers, combining MR with PET imaging may enrich our ability to investigate connectivity by introducing the concept of metabolic connectivity and cometomics and promoting new insights on the physiological and molecular bases underlying high-level neural organization. This review aims to describe and summarize the main methods of analysis of brain connectivity employed in MR imaging and nuclear medicine. Moreover, it will discuss practical aspects and state-of-the-art techniques for exploiting hybrid PET/MR imaging to investigate the relationship of physiological processes and brain connectivity. PMID:26973446

  6. Molecular imaging of brain tumors with radiolabeled choline PET.

    PubMed

    Calabria, Ferdinando Franco; Barbarisi, Manlio; Gangemi, Vincenzo; Grillea, Giovanni; Cascini, Giuseppe Lucio

    2016-05-26

    Several positron emission tomography (PET) radiopharmaceuticals have been emerged in the last decade as feasible in the management of brain lesions, due to the low performance in this field of the 18F-fluoro-deoxyglucose (18F-FDG), for its high physiological gradient of distribution in the brain. Beyond its usefulness in prostate cancer imaging, the radiolabeled choline is becoming a promising tool in diagnosing benign and malignant lesions of the brain, due to a very low rate of distribution in normal white and grey matters. The aim of our review was to assess the real impact of the radiolabeled choline PET/CT in the management of brain benign lesions, brain tumors, and metastases. Furthermore, emphasis was given to the comparison between the radiolabeled choline and the other radiopharmaceuticals in this field. A literature review was performed. The radiolabeled choline is useful in the management of patients with suspected brain tumor relapse, especially in association with magnetic resonance imaging (MRI), with caution regarding its intrinsic characteristic of non-tumor-specific tracer. For the same reason, it is not useful in the early evaluation of brain lesions. Similar results are reported for other radiopharmaceuticals. The inclusion of the head in the whole-body scans for somatic tumors is necessary to ensure metastases in the brain or choline-avid benign lesions.

  7. Simultaneous MRI and PET imaging of a rat brain

    NASA Astrophysics Data System (ADS)

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

    2006-12-01

    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.

  8. Performance modeling of a wearable brain PET (BET) camera

    NASA Astrophysics Data System (ADS)

    Schmidtlein, C. R.; Turner, J. N.; Thompson, M. O.; Mandal, K. C.; Häggström, I.; Zhang, J.; Humm, J. L.; Feiglin, D. H.; Krol, A.

    2016-03-01

    Purpose: To explore, by means of analytical and Monte Carlo modeling, performance of a novel lightweight and low-cost wearable helmet-shaped Brain PET (BET) camera based on thin-film digital Geiger Avalanche Photo Diode (dGAPD) with LSO and LaBr3 scintillators for imaging in vivo human brain processes for freely moving and acting subjects responding to various stimuli in any environment. Methods: We performed analytical and Monte Carlo modeling PET performance of a spherical cap BET device and cylindrical brain PET (CYL) device, both with 25 cm diameter and the same total mass of LSO scintillator. Total mass of LSO in both the BET and CYL systems is about 32 kg for a 25 mm thick scintillator, and 13 kg for 10 mm thick scintillator (assuming an LSO density of 7.3 g/ml). We also investigated a similar system using an LaBr3 scintillator corresponding to 22 kg and 9 kg for the 25 mm and 10 mm thick systems (assuming an LaBr3 density of 5.08 g/ml). In addition, we considered a clinical whole body (WB) LSO PET/CT scanner with 82 cm ring diameter and 15.8 cm axial length to represent a reference system. BET consisted of distributed Autonomous Detector Arrays (ADAs) integrated into Intelligent Autonomous Detector Blocks (IADBs). The ADA comprised of an array of small LYSO scintillator volumes (voxels with base a×a: 1.0 <= a <= 2.0 mm and length c: 3.0 <= c <= 6.0 mm) with 5-65 μm thick reflective layers on its five sides and sixth side optically coupled to the matching array of dGAPDs and processing electronics with total thickness of 50 μm. Simulated energy resolution was 10.8% and 3.3% for LSO and LaBr3 respectively and the coincidence window was set at 2 ns. The brain was simulated as a sphere of uniform F-18 activity with diameter of 10 cm embedded in a center of water sphere with diameter of 10 cm. Results: Analytical and Monte Carlo models showed similar results for lower energy window values (458 keV versus 445 keV for LSO, and 492 keV versus 485 keV for LaBr3

  9. Analysis and correction of count rate reduction during simultaneous MR-PET measurements with the BrainPET scanner.

    PubMed

    Weirich, Christoph; Brenner, Daniel; Scheins, Jürgen; Besancon, Etienne; Tellmann, Lutz; Herzog, Hans; Shah, N Jon

    2012-07-01

    In hybrid magnetic resonance-positron emission tomography (MR-PET) studies with the Siemens 3T MR-BrainPET scanner an instantaneous reduction of the PET sensitivity was observed during execution of certain MR sequences. This interference was investigated in detail with custom-made as well as standard clinical MR sequences. The radio-frequency pulses, the switched gradient fields and the constant magnetic field were examined as the relevant parameters of the magnetic resonance imaging (MRI) system as well as the air temperature within the PET detectors. Our investigation comprised the analysis of the analog PET signals, the total count rates, the geometric distribution of the count rate reduction within the BrainPET detector as well as reconstructed images. The fast switching magnetic field gradients were identified to distort the analog PET detector signals. The measured count rate reduction was found to be less than 3%, but only up to 2% in the case of echo planar imaging sequences, as applied in functional MRI. For clinical sequences routinely used in hybrid MR-BrainPET measurements, a correction method has been designed, implemented, and evaluated .

  10. Optimising rigid motion compensation for small animal brain PET imaging

    NASA Astrophysics Data System (ADS)

    Spangler-Bickell, Matthew G.; Zhou, Lin; Kyme, Andre Z.; De Laat, Bart; Fulton, Roger R.; Nuyts, Johan

    2016-10-01

    Motion compensation (MC) in PET brain imaging of awake small animals is attracting increased attention in preclinical studies since it avoids the confounding effects of anaesthesia and enables behavioural tests during the scan. A popular MC technique is to use multiple external cameras to track the motion of the animal’s head, which is assumed to be represented by the motion of a marker attached to its forehead. In this study we have explored several methods to improve the experimental setup and the reconstruction procedures of this method: optimising the camera-marker separation; improving the temporal synchronisation between the motion tracker measurements and the list-mode stream; post-acquisition smoothing and interpolation of the motion data; and list-mode reconstruction with appropriately selected subsets. These techniques have been tested and verified on measurements of a moving resolution phantom and brain scans of an awake rat. The proposed techniques improved the reconstructed spatial resolution of the phantom by 27% and of the rat brain by 14%. We suggest a set of optimal parameter values to use for awake animal PET studies and discuss the relative significance of each parameter choice.

  11. PET imaging reveals brain functional changes in internet gaming disorder.

    PubMed

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

    2014-07-01

    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 D2 (D2)/Serotonin 2A (5-HT2A) receptor function and glucose metabolism in the same subjects by positron emission tomography (PET) imaging approach, and investigate whether the correlation exists between D2 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 D2/5-HT2A 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 D2 receptors was observed in the striatum, and was correlated to years of overuse. A low level of D2 receptors in the striatum was significantly associated with decreased glucose metabolism in the orbitofrontal cortex. For the first time, we report the evidence that D2 receptor level is significantly associated with glucose metabolism in the same individuals with internet gaming disorder, which indicates that D2/5-HT2A receptor-mediated dysregulation of the orbitofrontal cortex could underlie a mechanism for loss of control and compulsive behavior in internet gaming disorder subjects.

  12. Quantitative relationship between coronary artery calcium score and hyperemic myocardial blood flow as assessed by hybrid 15O-water PET/CT imaging in patients evaluated for coronary artery disease.

    PubMed

    Danad, Ibrahim; Raijmakers, Pieter G; Appelman, Yolande E; Harms, Hendrik J; de Haan, Stefan; Marques, Koen M; van Kuijk, Cornelis; Allaart, Cornelis P; Hoekstra, Otto S; Lammertsma, Adriaan A; Lubberink, Mark; van Rossum, Albert C; Knaapen, Paul

    2012-04-01

    The incremental value of CAC over traditional risk factors to predict coronary vasodilator dysfunction and inherent myocardial blood flow (MBF) impairment is only scarcely documented (MBF). The aim of this study was therefore to evaluate the relationship between CAC content, hyperemic MBF, and coronary flow reserve (CFR) in patients undergoing hybrid (15)O-water PET/CT imaging. We evaluated 173 (mean age 56 ± 10, 78 men) patients with a low to intermediate likelihood for coronary artery disease (CAD), without a documented history of CAD, undergoing vasodilator stress (15)O-water PET/CT and CAC scoring. Obstructive coronary artery disease was excluded by means of invasive (n = 44) or CT-based coronary angiography (n = 129). 91 of 173 patients (52%) had a CAC score of zero. Of those with CAC, the CAC score was 0.1-99.9, 100-399.9, and ≥400 in 31%, 12%, and 5% of patients, respectively. Global CAC score showed significant inverse correlation with hyperemic MBF (r = -0.32, P < .001). With increasing CAC score, there was a decline in hyperemic MBF on a per-patient basis [3.70, 3.30, 2.68, and 2.53 mL · min(-1) · g(-1), with total CAC score of 0, 0.1-99.9, 100-399.9, and ≥400, respectively (P < .001)]. CFR showed a stepwise decline with increasing levels of CAC (3.70, 3.32, 2.94, and 2.93, P < .05). Multivariate analysis, including age, BMI, and CAD risk factors, revealed that only age, male gender, BMI, and hypercholesterolemia were associated with reduced stress perfusion. Furthermore, only diabetes and age were independently associated with CFR. In patients without significant obstructive CAD, a greater CAC burden is associated with a decreased hyperemic MBF and CFR. However, this association disappeared after adjustment for traditional CAD risk factors. These results suggest that CAC does not add incremental value regarding hyperemic MBF and CFR over established CAD risk factors in patients without obstructive CAD.

  13. Weight Gain following Pallidal Deep Brain Stimulation: A PET Study

    PubMed Central

    Sauleau, Paul; Drapier, Sophie; Duprez, Joan; Houvenaghel, Jean-François; Dondaine, Thibaut; Haegelen, Claire; Drapier, Dominique; Jannin, Pierre; Robert, Gabriel; Le Jeune, Florence; Vérin, Marc

    2016-01-01

    The mechanisms behind weight gain following deep brain stimulation (DBS) surgery seem to be multifactorial and suspected depending on the target, either the subthalamic nucleus (STN) or the globus pallidus internus (GPi). Decreased energy expenditure following motor improvement and behavioral and/or metabolic changes are possible explanations. Focusing on GPi target, our objective was to analyze correlations between changes in brain metabolism (measured with PET) and weight gain following GPi-DBS in patients with Parkinson’s disease (PD). Body mass index was calculated and brain activity prospectively measured using 2-deoxy-2[18F]fluoro-D-glucose PET four months before and four months after the start of GPi-DBS in 19 PD patients. Dopaminergic medication was included in the analysis to control for its possible influence on brain metabolism. Body mass index increased significantly by 0.66 ± 1.3 kg/m2 (p = 0.040). There were correlations between weight gain and changes in brain metabolism in premotor areas, including the left and right superior gyri (Brodmann area, BA 6), left superior gyrus (BA 8), the dorsolateral prefrontal cortex (right middle gyrus, BAs 9 and 46), and the left and right somatosensory association cortices (BA 7). However, we found no correlation between weight gain and metabolic changes in limbic and associative areas. Additionally, there was a trend toward a correlation between reduced dyskinesia and weight gain (r = 0.428, p = 0.067). These findings suggest that, unlike STN-DBS, motor improvement is the major contributing factor for weight gain following GPi-DBS PD, confirming the motor selectivity of this target. PMID:27070317

  14. Weight Gain following Pallidal Deep Brain Stimulation: A PET Study.

    PubMed

    Sauleau, Paul; Drapier, Sophie; Duprez, Joan; Houvenaghel, Jean-François; Dondaine, Thibaut; Haegelen, Claire; Drapier, Dominique; Jannin, Pierre; Robert, Gabriel; Le Jeune, Florence; Vérin, Marc

    2016-01-01

    The mechanisms behind weight gain following deep brain stimulation (DBS) surgery seem to be multifactorial and suspected depending on the target, either the subthalamic nucleus (STN) or the globus pallidus internus (GPi). Decreased energy expenditure following motor improvement and behavioral and/or metabolic changes are possible explanations. Focusing on GPi target, our objective was to analyze correlations between changes in brain metabolism (measured with PET) and weight gain following GPi-DBS in patients with Parkinson's disease (PD). Body mass index was calculated and brain activity prospectively measured using 2-deoxy-2[18F]fluoro-D-glucose PET four months before and four months after the start of GPi-DBS in 19 PD patients. Dopaminergic medication was included in the analysis to control for its possible influence on brain metabolism. Body mass index increased significantly by 0.66 ± 1.3 kg/m2 (p = 0.040). There were correlations between weight gain and changes in brain metabolism in premotor areas, including the left and right superior gyri (Brodmann area, BA 6), left superior gyrus (BA 8), the dorsolateral prefrontal cortex (right middle gyrus, BAs 9 and 46), and the left and right somatosensory association cortices (BA 7). However, we found no correlation between weight gain and metabolic changes in limbic and associative areas. Additionally, there was a trend toward a correlation between reduced dyskinesia and weight gain (r = 0.428, p = 0.067). These findings suggest that, unlike STN-DBS, motor improvement is the major contributing factor for weight gain following GPi-DBS PD, confirming the motor selectivity of this target.

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

    PubMed Central

    Lassen, Martin L.; Muzik, Otto; Beyer, Thomas; Hacker, Marcus; Ladefoged, Claes Nøhr; Cal-González, Jacobo; Wadsak, Wolfgang; Rausch, Ivo; Langer, Oliver; Bauer, Martin

    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 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 PMID:28769742

  16. Brain metastasis in carcinoma breast demonstrated on (68)Ga NOTA-bisphosphonate PET/CT.

    PubMed

    Passah, Averilicia; Tripathi, Madhavi; Kumar, Rajeev; Das, Chandan J; Goyal, Ankur; Bal, Chandrasekhar S

    2014-07-01

    Ga NOTA-bisphosphonate is a new bone-seeking PET radiotracer undergoing clinical evaluation. We report a case of a carcinoma breast who underwent Ga NOTA-bisphosphonate PET/CT for detection of skeletal metastasis. In addition to skeletal metastasis, a focal area of abnormal radiotracer uptake was noted in the brain, which was confirmed as brain metastasis on MRI.

  17. Measuring dopamine release in the human brain with PET

    SciTech Connect

    Volkow, N.D. |; Fowler, J.S.; Logan, J.; Wang, G.J.

    1995-12-01

    The dopamine system is involved in the regulation of brain regions that subserve motor, cognitive and motivational behaviors. Disruptions of dopamine (DA) function have ben implicated in neurological and psychiatric illnesses including substance abuse as well as on some of the deficits associated with aging of the human brain. This has made the DA system an important topic in research in the neurosciences and neuroimaging as well as an important molecular target for drug development. Positron Emission Tomography (PET), was the first technology that enabled direct measurement of components of the DA system in the living human brain. Imaging studies of DA in the living brain have been indirect, relying on the development of radiotracers to label DA receptors, DA transporters, compounds which have specificity for the enzymes which degrade synaptic DA. Additionally, through the use of tracers that provide information on regional brain activity (ie brain glucose metabolism and cerebral blood flow) and of appropriate pharmacological interventions, it has been possible to assess the functional consequences of changes in brain DA activity. DA specific ligands have been useful in the evaluation of patients with neuropsychiatric illnesses as well as to investigate receptor blockade by antipsychotic drugs. A limitation of strategies that rely on the use of DA specific ligands is that the measures do not necessarily reflect the functional state of the dopaminergic system and that there use to study the effects of drugs is limited to the investigation of receptor or transporter occupancy. Newer strategies have been developed in an attempt to provide with information on dopamine release and on the functional responsivity of the DA system in the human brain. This in turn allows to investigate the effects of pharmacological agent in an analogous way to what is done with microdialysis techniques.

  18. FDOPA PET-CT of Nonenhancing Brain Tumors.

    PubMed

    Bund, Caroline; Heimburger, Céline; Imperiale, Alessio; Lhermitte, Benoît; Chenard, Marie-Pierre; Lefebvre, François; Kremer, Stéphane; Proust, François; Namer, Izzie-Jacques

    2017-04-01

    Primary brain tumor grading is crucial to rapidly determine the therapeutic impact and prognosis of a brain tumor as well as the tumors' aggressiveness profile. On magnetic resonance imaging, high-grade tumors are usually responsible for blood -brain barrier breakdowns, which result in tumor enhancement. However, this is not always the case. The main objective of this study was to evaluate the diagnostic value of FDOPA PET in the assessment of primary brain tumor aggressiveness with no contrast enhancement on MRI. Fifty-three patients were prospectively included: 35 low-grade and 18 high-grade histologically proven gliomas, with no contrast enhancement. Each patient underwent static PET acquisitions at 30 minutes. All patients had MRSI with measurements of different metabolites ratio. FDOPA was useful in the subgroup of low-grade gliomas, discriminating between dysembryoplastic neuroepithelial tumor and grade II oligodendroglioma (P < 0.01). An optimal threshold of the maximum standardized uptake value at 30 minutes (SUVmax (T/N)30) = 2.16 to discriminated low- from high-grade gliomas with a sensitivity of 60%, specificity of 100%, PPV of 100%, and NPV of 83.33% (P < 0.01). The nCho/Cr and nCho/NAA ratios were significantly higher in high- than in low-grade gliomas (P < 0.03 and P < 0.04, respectively). A significant positive correlation between MRSI ratios and SUVmax was found. Including data from amino acid metabolism used alone or in association with MRSI allows us to discriminate between dysembryoplastic neuroepithelial tumor and grade II oligodendroglioma and between low- and high-grade gliomas with no contrast enhancement on MRI.

  19. PET imaging of ischemia-induced impairment of mitochondrial complex I function in monkey brain

    PubMed Central

    Tsukada, Hideo; Ohba, Hiroyuki; Nishiyama, Shingo; Kanazawa, Masakatsu; Kakiuchi, Takeharu; Harada, Norihiro

    2014-01-01

    To assess the capability of 18F-2-tert-butyl-4-chloro-5-{6-[2-(2-fluoroethoxy)-ethoxy]-pyridin-3-ylmethoxy}-2H-pyridazin-3-one (18F-BCPP-EF), a novel positron emission tomography (PET) probe for mitochondrial complex I (MC-I) activity, as a specific marker of ischemia-induced neuronal death without being disturbed by inflammation, translational research was conducted using an animal PET in ischemic brains of Cynomolgus monkeys (Macaca fascicularis). Focal ischemia was induced by the right middle cerebral artery occlusion for 3 hours, then PET scans were conducted at Day-7 with 15O-gases for regional cerebral blood flow (rCBF) and regional cerebral metabolism of oxygen (rCMRO2), and 18F-BCPP-EF for MC-I with arterial blood sampling. On Day-8, the additional PET scans conducted with 11C-flumazenil (11C-FMZ) for central-type benzodiazepine receptors, 11C-PBR28 for translocator protein, and 18F-fluoro-2-deoxy-D-glucose (18F-FDG) for regional cerebral metabolic rate of glucose (rCMRglc). The total distribution volume (VT) values of 18F-BCPP-EF showed the significant reduction in MC-I activity in the damaged area at Day-7. When correlated with rCBF and rCMRO2, the VT values of 18F-BCPP-EF provided better correlation with rCMRO2 than with rCBF. In the inflammatory regions (region of interest, ROIPBR) of the ischemic hemisphere detected with 11C-PBR28, higher 18F-FDG uptake and lower VT of 18F-BCPP-EF, 11C-FMZ, and rCMRO2 than those in normal contralateral hemisphere were observed. These results strongly suggested that 18F-BCPP-EF could discriminate the neuronal damaged areas with neuroinflammation, where 18F-FDG could not owing to its high uptake into the activated microglia. PMID:24447952

  20. Clinical applications of choline PET/CT in brain tumors.

    PubMed

    Giovannini, Elisabetta; Lazzeri, Patrizia; Milano, Amalia; Gaeta, Maria Chiara; Ciarmiello, Andrea

    2015-01-01

    Malignant gliomas and metastatic tumors are the most common forms of brain tumors. From a clinical perspective, neuroimaging plays a significant role, in diagnosis, treatment planning, and follow-up. To date MRI is considered the current clinical gold standard for imaging, however, despite providing superior structural detail it features poor specificity in identifying viable tumors in brain treated with surgery, radiation, or chemotherapy. In the last years functional neuroimaging has become largely widespread thanks to the use of molecular tracers employed in cellular metabolism which has significantly improved the management of patients with brain tumors, especially in the post-treatment phase. Despite the considerable progress of molecular imaging in oncology its use in the diagnosis of brain tumors is still limited by a few wellknown technical problems. Because 18F-FDG, the most common radiotracer used in oncology, is avidly accumulated by normal cortex, the low tumor/background signal ratio makes it difficult to distinguish the tumor from normal surrounding tissues. By contrast, radiotracers with higher specificity for the tumor are labeled with a short half-life isotopes which restricts their use to those centers equipped with a cyclotron and radiopharmacy facility. 11C-choline has been reported as a suitable tracer for neuroimaging application. The recent availability of choline labeled with a long half-life radioisotope as 18F increases the possibility of studying this tracer's potential role in the staging of brain tumors. The present review focuses on the possible clinical applications of PET/CT with choline tracers in malignant brain tumors and brain metastases, with a special focus on malignant gliomas.

  1. Comparison of analytical methods of brain [(18)F]FDG-PET after severe traumatic brain injury.

    PubMed

    Madsen, Karine; Hesby, Sara; Poulsen, Ingrid; Fuglsang, Stefan; Graff, Jesper; Larsen, Karen B; Kammersgaard, Lars P; Law, Ian; Siebner, Hartwig R

    2017-08-12

    Loss of consciousness has been shown to reduce cerebral metabolic rates of glucose (CMRglc) measured by brain [(18)F]FDG-PET. Measurements of regional metabolic patterns by normalization to global cerebral metabolism or cerebellum may underestimate widespread reductions. The aim of this study was to compare quantification methods of whole brain glucose metabolism, including whole brain [18F]FDG uptake normalized to uptake in cerebellum, normalized to injected activity, normalized to plasma tracer concentration, and two methods for estimating CMRglc. Six patients suffering from severe traumatic brain injury (TBI) and ten healthy controls (HC) underwent a 10min static [(18)F]FDG-PET scan and venous blood sampling. Except from normalizing to cerebellum, all quantification methods found significant lower level of whole brain glucose metabolism of 25-33% in TBI patients compared to HC. In accordance these measurements correlated to level of consciousness. Our study demonstrates that the analysis method of the [(18)F]FDG PET data has a substantial impact on the estimated whole brain cerebral glucose metabolism in patients with severe TBI. Importantly, the SUVR method which is often used in a clinical setting was not able to distinguish patients with severe TBI from HC at the whole-brain level. We recommend supplementing a static [(18)F]FDG scan with a single venous blood sample in future studies of patients with severe TBI or reduced level of consciousness. This can be used for simple semi-quantitative uptake values by normalizing brain activity uptake to plasma tracer concentration, or quantitative estimates of CMRglc. Copyright © 2017. Published by Elsevier B.V.

  2. Brain PET metabolic abnormalities in a case of varicella-zoster virus encephalitis.

    PubMed

    Coiffard, Benjamin; Guedj, Eric; Daumas, Aurélie; Leveque, Pierre; Villani, Patrick

    2014-09-01

    The role of brain 18F-FDG PET in the diagnostic evaluation of encephalitis has been recently suggested, especially in limbic encephalitis, but descriptions are mainly limited to small case reports. However, the evaluation of cerebral metabolism by 18F-FDG PET has never been described for varicella-zoster virus encephalitis. We report the first case of varicella-zoster virus encephalitis in which 18F-FDG PET revealed brain metabolic abnormalities. Brain metabolic PET imaging was analyzed by comparing the patient's brain 18F-FDG PET scans to that of 12 healthy subjects. Compared with healthy subjects, significant hypometabolism and hypermetabolism were found and evolved over time with treatment.

  3. Brain tissue segmentation in PET-CT images using probabilistic atlas and variational Bayes inference.

    PubMed

    Xia, Yong; Wang, Jiabin; Eberl, Stefan; Fulham, Michael; Feng, David Dagan

    2011-01-01

    PET-CT provides aligned anatomical (CT) and functional (PET) images in a single scan, and has the potential to improve brain PET image segmentation, which can in turn improve quantitative clinical analyses. We propose a statistical segmentation algorithm that incorporates the prior anatomical knowledge represented by probabilistic brain atlas into the variational Bayes inference to delineate gray matter (GM), white matter (WM) and cerebrospinal fluid (CSF) in brain PET-CT images. Our approach adds an additional novel aspect by allowing voxels to have variable and adaptive prior probabilities of belonging to each class. We compared our algorithm to the segmentation approaches implemented in the expectation maximization segmentation (EMS) and statistical parametric mapping (SPM8) packages in 26 clinical cases. The results show that our algorithm improves the accuracy of brain PET-CT image segmentation.

  4. Brain shaving: adaptive detection for brain PET data

    NASA Astrophysics Data System (ADS)

    Grecchi, Elisabetta; Doyle, Orla M.; Bertoldo, Alessandra; Pavese, Nicola; Turkheimer, Federico E.

    2014-05-01

    The intricacy of brain biology is such that the variation of imaging end-points in health and disease exhibits an unpredictable range of spatial distributions from the extremely localized to the very diffuse. This represents a challenge for the two standard approaches to analysis, the mass univariate and the multivariate that exhibit either strong specificity but not as good sensitivity (the former) or poor specificity and comparatively better sensitivity (the latter). In this work, we develop an analytical methodology for positron emission tomography that operates an extraction (‘shaving’) of coherent patterns of signal variation while maintaining control of the type I error. The methodology operates two rotations on the image data, one local using the wavelet transform and one global using the singular value decomposition. The control of specificity is obtained by using the gap statistic that selects, within each eigenvector, a subset of significantly coherent elements. Face-validity of the algorithm is demonstrated using a paradigmatic data-set with two radiotracers, [11C]-raclopride and [11C]-(R)-PK11195, measured on the same Huntington's disease patients, a disorder with a genetic based diagnosis. The algorithm is able to detect the two well-known separate but connected processes of dopamine neuronal loss (localized in the basal ganglia) and neuroinflammation (diffusive around the whole brain). These processes are at the two extremes of the distributional envelope, one being very sparse and the latter being perfectly Gaussian and they are not adequately detected by the univariate and the multivariate approaches.

  5. Evaluation of a novel PDE10A PET radioligand, [(11) C]T-773, in nonhuman primates: brain and whole body PET and brain autoradiography.

    PubMed

    Takano, Akihiro; Stepanov, Vladimir; Gulyás, Balázs; Nakao, Ryuji; Amini, Nahid; Miura, Shotaro; Kimura, Haruhide; Taniguchi, Takahiko; Halldin, Christer

    2015-07-01

    Phosphodiesterase 10A (PDE10A) is considered to be a key target for the treatment of several neuropsychiatric diseases. The characteristics of [(11) C]T-773, a novel positron emission tomography (PET) radioligand with high binding affinity and selectivity for PDE10A, were evaluated in autoradiography and in nonhuman primate (NHP) PET. Brain PET measurements were performed under baseline conditions and after administration of a selective PDE10A inhibitor, MP-10. Total distribution volume (VT ) and binding potential (BPND ) were calculated using various kinetic models. Whole body PET measurements were performed to calculate the effective dose of [(11) C]T-773. Autoradiography studies in postmortem human and monkey brain sections showed high accumulation of [(11) C]T-773 in the striatum and substantia nigra which was blocked by MP-10. Brain PET showed high accumulation of [(11) C]T-773 in the striatum, and the data could be fitted using a two tissue compartment model. BPND was approximately 1.8 in the putamen when the cerebellum was used as the reference region. Approximately 70% of PDE10A binding was occupied by 1.8 mg/kg of MP-10. Whole body PET showed high accumulation of [(11) C]T-773 in the liver, kidney, heart, and brain in the initial phase. The radioligand was partly excreted via bile and the gastrointestinal tract, and partly excreted through the urinary tract. The calculated effective dose was 0.007 mSv/MBq. In conclusion, [(11) C]T-773 was demonstrated to be a promising PET radioligand for PDE10A with favorable brain kinetics. Dosimetry results support multiple PET measurements per person in human studies. Further research is required with [(11) C]T-773 in order to test the radioligand's potential clinical applications.

  6. Optimization of PET instrumentation for brain activation studies

    SciTech Connect

    Dahlbom, M.; Cherry, S.R.; Hoffman, E.J. . Dept. of Radiological Science); Eriksson, L. . Dept. of Clinical Neurophysiology); Wienhard, K. )

    1993-08-01

    By performing cerebral blood flow studies with positron emission tomography (PET), and comparing blood flow images of different states of activation, functional mapping of the brain is possible. The ability of current commercial instruments to perform such studies is investigated in this work, based on a comparison of noise equivalent count (NEC) rates. Differences in the NEC performance of the different scanners in conjunction with scanner design parameters, provide insights into the importance of block design (size, dead time, crystal thickness) and overall scanner design (sensitivity and scatter fraction) for optimizing data from activation studies. The newer scanners with removable septa, operating with 3-D acquisition, have much higher sensitivity, but require new methodology for optimized operation. Only by administering multiple low doses (fractionation) of the flow tracer can the high sensitivity be utilized.

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

    NASA Astrophysics Data System (ADS)

    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

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

    PubMed

    Merida, Ines; Reilhac, Anthonin; Redoute, Jerome; Heckemann, Rolf; Costes, Nicolas; Hammers, Alexander

    2017-02-09

    Introduction 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. Methods 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). Results 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

  9. Effect of Attenuation Correction on Regional Quantification Between PET/MR and PET/CT: A Multicenter Study Using a 3-Dimensional Brain Phantom.

    PubMed

    Teuho, Jarmo; Johansson, Jarkko; Linden, Jani; Hansen, Adam Espe; Holm, Søren; Keller, Sune H; Delso, Gaspar; Veit-Haibach, Patrick; Magota, Keiichi; Saunavaara, Virva; Tolvanen, Tuula; Teräs, Mika; Iida, Hidehiro

    2016-05-01

    A spatial bias in brain PET/MR exists compared with PET/CT, because of MR-based attenuation correction. We performed an evaluation among 4 institutions, 3 PET/MR systems, and 4 PET/CT systems using an anthropomorphic brain phantom, hypothesizing that the spatial bias would be minimized with CT-based attenuation correction (CTAC). The evaluation protocol was similar to the quantification of changes in neurologic PET studies. Regional analysis was conducted on 8 anatomic volumes of interest (VOIs) in gray matter on count-normalized, resolution-matched, coregistered data. On PET/MR systems, CTAC was applied as the reference method for attenuation correction. With CTAC, visual and quantitative differences between PET/MR and PET/CT systems were minimized. Intersystem variation between institutions was +3.42% to -3.29% in all VOIs for PET/CT and +2.15% to -4.50% in all VOIs for PET/MR. PET/MR systems differed by +2.34% to -2.21%, +2.04% to -2.08%, and -1.77% to -5.37% when compared with a PET/CT system at each institution, and these differences were not significant (P ≥ 0.05). Visual and quantitative differences between PET/MR and PET/CT systems can be minimized by an accurate and standardized method of attenuation correction. If a method similar to CTAC can be implemented for brain PET/MRI, there is no reason why PET/MR should not perform as well as PET/CT. © 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

  10. [In vivo visualization of neurotransmitter function in the human brain by PET].

    PubMed

    Itoh, M; Yanai, K; Yamaguchi, S; Fujiwara, T; Nagasawa, H; Yokoyama, H; Iinuma, K; Ido, T

    1995-03-01

    Measurement of cerebral blood flow and energy metabolism using PET with 15O and 18F labeled tracers allows quantitative evaluation of cerebral metabolism that can be perturbed in pathological states. Neurotransmission is a new target that is visualized by labeling of substrates of enzymes that are involved in neurotransmitter synthesis or degradation. Neuronal receptors are mapped by introducing the labeled ligands that are specifically bound to the receptors in question. We developed unique tracers that label dopamine D2 or histamine H1 receptors. With other available ligands for the muscarinic cholinergic receptors and [18F] fluorodopa, we started clinical investigations to document the state of neurotransmission in patients with epilepsy, Parkinson's disease and dementia. Using [11C] doxepin we observed an increase of H1 receptors in the epileptic foci that showed decreased glucose metabolic rate at the interictal phase. This phenomenon is compatible with reported increase of mu opiate receptors in the brains of epileptic patients. Brain uptake of FDOPA (Ki), calculated by the graphical plot was found relatively stable with age both in the normal population and dementia patients. However, the striatal Ki of FDOPA of severely demented patients significantly reduced, compared with the normal aged subjects. The correlation analysis between FDOPA Ki and severity of dementia as assessed by mini-mental state examination revealed a significant reduction of Ki associated with the disease progression. Increase in D2 receptor density as assessed by the uptake of YM 09151-2 was observed in cases with reduced FDOPA uptake, which may correspond to the state of supersensitivity of the D2 receptors.

  11. Compartmental analysis of washout effect in rat brain: in-beam OpenPET measurement using a (11)C beam.

    PubMed

    Hirano, Yoshiyuki; Kinouchi, Shoko; Ikoma, Yoko; Yoshida, Eiji; Wakizaka, Hidekazu; Ito, Hiroshi; Yamaya, Taiga

    2013-12-07

    In-beam positron emission tomography (PET) is expected to enable visualization of a dose verification using positron emitters (β+ decay). For accurate dose verification, correction of the washout of the positron emitters should be made. In addition, the quantitative washout rate has a potential usefulness as a diagnostic index, but modeling for this has not been studied yet. In this paper, therefore, we applied compartment analyses to in-beam PET data acquired by our small OpenPET prototype, which has a physically opened field-of-view (FOV) between two detector rings. A rat brain was located at the FOV and was irradiated by a (11)C beam. Time activity curves of the irradiated field were measured immediately after the irradiations, and the washout rate was obtained based on two models: the two-washout model (medium decay, k2m; slow decay, k2s) developed in a study of rabbit irradiation; and the two-compartment model used in nuclear medicine, where efflux from tissue to blood (k2), influx (k3) and efflux (k4) from the first to second compartments in tissue were evaluated. The observed k2m and k2s were 0.34 and 0.005 min(-1), respectively, which was consistent with the rabbit study. Also k2m was close to the washout rate in cerebral blood flow (CBF) measurements by dynamic PET with (15)O-water, while, k2, k3, and k4 were 0.16, 0.15 and 0.007 min(-1). Our present work suggested the dynamics of (11)C might be relevant to CBF or permeability of a molecule containing (11)C atoms might be regulated by a transporter because the k2 was relatively low compared with a simple diffusion tracer.

  12. Impact of metal artefacts due to EEG electrodes in brain PET/CT imaging.

    PubMed

    Lemmens, Catherine; Montandon, Marie-Louise; Nuyts, Johan; Ratib, Osman; Dupont, Patrick; Zaidi, Habib

    2008-08-21

    The goal of this study is to investigate the impact of electroencephalogram (EEG) electrodes on the visual quality and quantification of (18)F-FDG PET images in neurological PET/CT examinations. For this purpose, the scans of 20 epilepsy patients with EEG monitoring were used. The CT data were reconstructed with filtered backprojection (FBP) and with a metal artefact reduction (MAR) algorithm. Both data sets were used for CT-based attenuation correction (AC) of the PET data. Also, a calculated AC (CALC) technique was considered. A volume of interest (VOI)-based analysis and a voxel-based quantitative analysis were performed to compare the different AC methods. Images were also evaluated visually by two observers. It was shown with simulations and phantom measurements that from the considered AC methods, the MAR-AC can be used as the reference in this setting. The visual assessment of PET images showed local hot spots outside the brain corresponding to the locations of the electrodes when using FBP-AC. In the brain, no abnormalities were observed. The quantitative analysis showed a very good correlation between PET-FBP-AC and PET-MAR-AC, with a statistically significant positive bias in the PET-FBP-AC images of about 5-7% in most brain voxels. There was also good correlation between PET-CALC-AC and PET-MAR-AC, but in the PET-CALC-AC images, regions with both a significant positive and negative bias were observed. EEG electrodes give rise to local hot spots outside the brain and a positive quantification bias in the brain. However, when diagnosis is made by mere visual assessment, the presence of EEG electrodes does not seem to alter the diagnosis. When quantification is performed, the bias becomes an issue especially when comparing brain images with and without EEG monitoring.

  13. Impact of metal artefacts due to EEG electrodes in brain PET/CT imaging

    NASA Astrophysics Data System (ADS)

    Lemmens, Catherine; Montandon, Marie-Louise; Nuyts, Johan; Ratib, Osman; Dupont, Patrick; Zaidi, Habib

    2008-08-01

    The goal of this study is to investigate the impact of electroencephalogram (EEG) electrodes on the visual quality and quantification of 18F-FDG PET images in neurological PET/CT examinations. For this purpose, the scans of 20 epilepsy patients with EEG monitoring were used. The CT data were reconstructed with filtered backprojection (FBP) and with a metal artefact reduction (MAR) algorithm. Both data sets were used for CT-based attenuation correction (AC) of the PET data. Also, a calculated AC (CALC) technique was considered. A volume of interest (VOI)-based analysis and a voxel-based quantitative analysis were performed to compare the different AC methods. Images were also evaluated visually by two observers. It was shown with simulations and phantom measurements that from the considered AC methods, the MAR-AC can be used as the reference in this setting. The visual assessment of PET images showed local hot spots outside the brain corresponding to the locations of the electrodes when using FBP-AC. In the brain, no abnormalities were observed. The quantitative analysis showed a very good correlation between PET-FBP-AC and PET-MAR-AC, with a statistically significant positive bias in the PET-FBP-AC images of about 5-7% in most brain voxels. There was also good correlation between PET-CALC-AC and PET-MAR-AC, but in the PET-CALC-AC images, regions with both a significant positive and negative bias were observed. EEG electrodes give rise to local hot spots outside the brain and a positive quantification bias in the brain. However, when diagnosis is made by mere visual assessment, the presence of EEG electrodes does not seem to alter the diagnosis. When quantification is performed, the bias becomes an issue especially when comparing brain images with and without EEG monitoring.

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

    PubMed Central

    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

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

    PubMed

    Wey, Hsiao-Ying; Catana, Ciprian; Hooker, Jacob M; Dougherty, Darin D; Knudsen, Gitte M; Wang, Danny J J; Chonde, Daniel B; Rosen, Bruce R; Gollub, Randy L; Kong, Jian

    2014-11-15

    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 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 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 and striatum related to pain processing, while modality specific brain networks were also found. Co-localized fMRI and PET signal changes in the thalamus were positively correlated suggesting that pain-induced changes in opioid neurotransmission contribute a significant component of the fMRI signal change in this region. Simultaneous fMRI-PET provides unique opportunities allowing us to relate specific neurochemical events to functional hemodynamic activation and to investigate the impacts of neurotransmission on neurovascular coupling of the human brain in vivo.

  16. System for cerebral blood flow measurement using an H/sub 2//sup 15/O autoradiographic method and positron emission tomography

    SciTech Connect

    Kanno, I.; Iida, H.; Miura, S.; Murakami, M.; Takahashi, K.; Sasaki, H.; Inugami, A.; Shishido, F.; Uemura, K.

    1987-04-01

    A system for CBF measurement using an H/sub 2//sup 15/O autoradiographic method and positron emission tomography (PET) has been designed and installed as a clinical tool. Following an intravenous injection of H/sub 2//sup 15/O, a radioactivity accumulation in the brain tissue for 60 s and a continuous record of radioactivity in arterial blood were measured by a high counting speed PET device and a beta-ray detector, respectively, and CBF was calculated by a table-lookup procedure. First, this method was compared with the C/sup 15/O/sub 2/ inhalation steady-state method on 17 cerebrovascular disease patients and four normal subjects. The two values for CBF agreed with each other when H/sub 2//sup 15/O autoradiographic method was applied by correction for the dispersion in the measured arterial radioactivity-time curve. However, without the correction, the CBF by the H/sub 2//sup 15/O autoradiographic method revealed substantial overestimation by 30.6 +/- 17.5%. A reduced gray/white ratio of CBF was also observed in the H/sub 2//sup 15/O autoradiographic method. Second, simulation was performed in order to determine optimal accumulation time by PET scan; the result was that errors due to dispersion and time mismatch became critical as the accumulation time was shortened to less than 60 s.

  17. Current status of 18F-DOPA PET imaging in the detection of brain tumor recurrence.

    PubMed

    Calabria, Ferdinando; Cascini, Giuseppe Lucio

    2015-01-01

    Considering the intrinsic limits of fluorine-18-dfluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) for diagnosing brain tumors and tumor recurrence, several radiopharmaceuticals have been developed to detect brain tumor recurrence after treatment. Among others, a promising tracer is fluorine-18-desoxyphenylalanine (DOPA), due to its very low rate of physiological distribution in normal brain structures of white and grey matter. The aim of our study was to assess the feasibility of PET/CT with (18)F-DOPA in the detection of brain tumor recurrence after treatment, in comparison with MRI performance and other PET radiopharmaceuticals, currently employed in this field. The (18)F-DOPA PET/CT seems to be useful in the diagnosis of patients with suspected brain tumor recurrence, because of low signal ratio in normal brain white and grey matter, in particular as compared to (18)F-FDG PET/CT low performance. Related data are presented for other fluorinated amino acid tracers. Magnetic resonance imaging is the gold standard of diagnosis and (18)F-DOPA PET/CT is adjuvant to diagnosis. Further studies are needed to enrich our knowledge about this promising tracer,(18)F-DOPA, especially on its possible role on semi-quantitative measurements in brain tumors.

  18. Framework for the construction of a Monte Carlo simulated brain PET-MR image database

    NASA Astrophysics Data System (ADS)

    Thomas, B. A.; Erlandsson, K.; Drobnjak, I.; Pedemonte, S.; Vunckx, K.; Bousse, A.; Reilhac-Laborde, A.; Ourselin, S.; Hutton, B. F.

    2014-01-01

    Simultaneous PET-MR acquisition reduces the possibility of registration mismatch between the two modalities. This facilitates the application of techniques, either during reconstruction or post-reconstruction, that aim to improve the PET resolution by utilising structural information provided by MR. However, in order to validate such methods for brain PET-MR studies it is desirable to evaluate the performance using data where the ground truth is known. In this work, we present a framework for the production of datasets where simulations of both the PET and MR, based on real data, are generated such that reconstruction and post-reconstruction approaches can be fairly compared.

  19. Simultaneous MR/PET imaging of the human brain: feasibility study.

    PubMed

    Schlemmer, Heinz-Peter W; Pichler, Bernd J; Schmand, Matthias; Burbar, Ziad; Michel, Christian; Ladebeck, Ralf; Jattke, Kirstin; Townsend, David; Nahmias, Claude; Jacob, Pradeep K; Heiss, Wolf-Dieter; Claussen, Claus D

    2008-09-01

    The purpose of this study was to apply a magnetic resonance (MR) imaging-compatible positron emission tomographic (PET) detector technology for simultaneous MR/PET imaging of the human brain and skull base. The PET detector ring consists of lutetium oxyorthosilicate (LSO) scintillation crystals in combination with avalanche photodiodes (APDs) mounted in a clinical 3-T MR imager with use of the birdcage transmit/receive head coil. Following phantom studies, two patients were simultaneously examined by using fluorine 18 fluorodeoxyglucose (FDG) PET and MR imaging and spectroscopy. MR/PET data enabled accurate coregistration of morphologic and multifunctional information. Simultaneous MR/PET imaging is feasible in humans, opening up new possibilities for the emerging field of molecular imaging. RSNA, 2008

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

    PubMed Central

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

    2011-01-01

    Interictal Brain F-18 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 hypomethabolism on FDG PET brain study of a 24-year-old male patient with temporal lobe epilepsy. PMID:22174515

  1. ViRPET--combination of virtual reality and PET brain imaging

    DOEpatents

    Majewski, Stanislaw; Brefczynski-Lewis, Julie

    2017-05-23

    Various methods, systems and apparatus are provided for brain imaging during virtual reality stimulation. In one example, among others, a system for virtual ambulatory environment brain imaging includes a mobile brain imager configured to obtain positron emission tomography (PET) scans of a subject in motion, and a virtual reality (VR) system configured to provide one or more stimuli to the subject during the PET scans. In another example, a method for virtual ambulatory environment brain imaging includes providing stimulation to a subject through a virtual reality (VR) system; and obtaining a positron emission tomography (PET) scan of the subject while moving in response to the stimulation from the VR system. The mobile brain imager can be positioned on the subject with an array of imaging photodetector modules distributed about the head of the subject.

  2. MR-Based PET Motion Correction Procedure for Simultaneous MR-PET Neuroimaging of Human Brain

    PubMed Central

    Weirich, Christoph; Rota Kops, Elena; Celik, Abdullah; Tellmann, Lutz; Stöcker, Tony; Herzog, Hans; Shah, Nadim Jon

    2012-01-01

    Positron Emission Tomography (PET) images are prone to motion artefacts due to the long acquisition time of PET measurements. Recently, simultaneous magnetic resonance imaging (MRI) and PET have become available in the first generation of Hybrid MR-PET scanners. In this work, the elimination of artefacts due to head motion in PET neuroimages is achieved by a new approach utilising MR-based motion tracking in combination with PET list mode data motion correction for simultaneous MR-PET acquisitions. The method comprises accurate MR-based motion measurements, an intra-frame motion minimising and reconstruction time reducing temporal framing algorithm, and a list mode based PET reconstruction which utilises the Ordinary Poisson Algorithm and avoids axial and transaxial compression. Compared to images uncorrected for motion, an increased image quality is shown in phantom as well as in vivo images. In vivo motion corrected images show an evident increase of contrast at the basal ganglia and a good visibility of uptake in tiny structures such as superior colliculi. PMID:23189127

  3. MR-based PET motion correction procedure for simultaneous MR-PET neuroimaging of human brain.

    PubMed

    Ullisch, Marcus Görge; Scheins, Jürgen Johann; Weirich, Christoph; Rota Kops, Elena; Celik, Abdullah; Tellmann, Lutz; Stöcker, Tony; Herzog, Hans; Shah, Nadim Jon

    2012-01-01

    Positron Emission Tomography (PET) images are prone to motion artefacts due to the long acquisition time of PET measurements. Recently, simultaneous magnetic resonance imaging (MRI) and PET have become available in the first generation of Hybrid MR-PET scanners. In this work, the elimination of artefacts due to head motion in PET neuroimages is achieved by a new approach utilising MR-based motion tracking in combination with PET list mode data motion correction for simultaneous MR-PET acquisitions. The method comprises accurate MR-based motion measurements, an intra-frame motion minimising and reconstruction time reducing temporal framing algorithm, and a list mode based PET reconstruction which utilises the Ordinary Poisson Algorithm and avoids axial and transaxial compression. Compared to images uncorrected for motion, an increased image quality is shown in phantom as well as in vivo images. In vivo motion corrected images show an evident increase of contrast at the basal ganglia and a good visibility of uptake in tiny structures such as superior colliculi.

  4. Mapping {sup 15}O Production Rate for Proton Therapy Verification

    SciTech Connect

    Grogg, Kira; Alpert, Nathaniel M.; Zhu, Xuping; Min, Chul Hee; Testa, Mauro; Winey, Brian; Normandin, Marc D.; Shih, Helen A.; Paganetti, Harald; Bortfeld, Thomas; El Fakhri, Georges

    2015-06-01

    Purpose: This work was a proof-of-principle study for the evaluation of oxygen-15 ({sup 15}O) production as an imaging target through the use of positron emission tomography (PET), to improve verification of proton treatment plans and to study the effects of perfusion. Methods and Materials: Dynamic PET measurements of irradiation-produced isotopes were made for a phantom and rabbit thigh muscles. The rabbit muscle was irradiated and imaged under both live and dead conditions. A differential equation was fitted to phantom and in vivo data, yielding estimates of {sup 15}O production and clearance rates, which were compared to live versus dead rates for the rabbit and to Monte Carlo predictions. Results: PET clearance rates agreed with decay constants of the dominant radionuclide species in 3 different phantom materials. In 2 oxygen-rich materials, the ratio of {sup 15}O production rates agreed with the expected ratio. In the dead rabbit thighs, the dynamic PET concentration histories were accurately described using {sup 15}O decay constant, whereas the live thigh activity decayed faster. Most importantly, the {sup 15}O production rates agreed within 2% (P>.5) between conditions. Conclusions: We developed a new method for quantitative measurement of {sup 15}O production and clearance rates in the period immediately following proton therapy. Measurements in the phantom and rabbits were well described in terms of {sup 15}O production and clearance rates, plus a correction for other isotopes. These proof-of-principle results support the feasibility of detailed verification of proton therapy treatment delivery. In addition, {sup 15}O clearance rates may be useful in monitoring permeability changes due to therapy.

  5. Mapping (15)O production rate for proton therapy verification.

    PubMed

    Grogg, Kira; Alpert, Nathaniel M; Zhu, Xuping; Min, Chul Hee; Testa, Mauro; Winey, Brian; Normandin, Marc D; Shih, Helen A; Paganetti, Harald; Bortfeld, Thomas; El Fakhri, Georges

    2015-06-01

    This work was a proof-of-principle study for the evaluation of oxygen-15 ((15)O) production as an imaging target through the use of positron emission tomography (PET), to improve verification of proton treatment plans and to study the effects of perfusion. Dynamic PET measurements of irradiation-produced isotopes were made for a phantom and rabbit thigh muscles. The rabbit muscle was irradiated and imaged under both live and dead conditions. A differential equation was fitted to phantom and in vivo data, yielding estimates of (15)O production and clearance rates, which were compared to live versus dead rates for the rabbit and to Monte Carlo predictions. PET clearance rates agreed with decay constants of the dominant radionuclide species in 3 different phantom materials. In 2 oxygen-rich materials, the ratio of (15)O production rates agreed with the expected ratio. In the dead rabbit thighs, the dynamic PET concentration histories were accurately described using (15)O decay constant, whereas the live thigh activity decayed faster. Most importantly, the (15)O production rates agreed within 2% (P>.5) between conditions. We developed a new method for quantitative measurement of (15)O production and clearance rates in the period immediately following proton therapy. Measurements in the phantom and rabbits were well described in terms of (15)O production and clearance rates, plus a correction for other isotopes. These proof-of-principle results support the feasibility of detailed verification of proton therapy treatment delivery. In addition, (15)O clearance rates may be useful in monitoring permeability changes due to therapy. Copyright © 2015 Elsevier Inc. All rights reserved.

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

    NASA Astrophysics Data System (ADS)

    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.

  7. Dynamic functional imaging of brain glucose utilization using fPET-FDG

    DOE PAGES

    Villien, Marjorie; Wey, Hsiao-Ying; Mandeville, Joseph B.; ...

    2014-06-14

    We report that 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 themore » 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. Ultimately, 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 are straightforward. fPET-FDG is a highly complementary technique to MRI and provides a rich new way to observe functional changes in brain metabolism.« less

  8. Dynamic Functional Imaging of Brain Glucose Utilization using fPET-FDG

    PubMed Central

    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

  9. Dynamic functional imaging of brain glucose utilization using fPET-FDG.

    PubMed

    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

    2014-10-15

    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-[(18)F]-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 are straightforward. fPET-FDG is a highly complementary technique to MRI and provides a rich new way to observe functional changes in brain metabolism.

  10. Kinetic measurements are necessary for description of brain receptors with PET

    SciTech Connect

    Ma, M.; Me, R.

    1984-01-01

    Following injection of radiolabeled spiperone a brain PET image demonstrates a distribution of tracer similar to the known distribution of dopamine receptors. However, the usefulness of a single PET image to quantitate receptor density can be limited by the effect of local blood flow (CBF), brain permeability (P), forward receptor rate constant (k1), and the reverse receptor rate constant (k-1). Using a 3-compartment model that the authors have described and successfully employed to interpret brain receptor kinetics with PET, the authors have simulated the effect of changes in the above variables on the image contrast (IC) between receptor-containing tissue (T), and receptor-free tissue like cerebellum (C), expressing this contrast as (T-C)/C. The blood activity curve and initial values for the variables were taken from their in vivo PET work in baboons using 18-F-spiperone. The model shows IC increases directly with time, not reaching 90% of maximum until over 3 hours. Thus, the timing of a single PET scan is critical for reproducible results. While the effect of changes in CBF are very small, changes in P, k1 and k-1 at 60 minutes, and k1 and k-1 at 120 minutes result in substantial changes in the observed IC. Until more is known about the behavior of these variables reliable description of brain receptors requires dynamic PET data from sequential images, analyzed by an appropriate mathematical model.

  11. Dynamic functional imaging of brain glucose utilization using fPET-FDG

    SciTech Connect

    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.

    2014-06-14

    We report that 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. Ultimately, 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 are straightforward. fPET-FDG is a highly complementary technique to MRI and provides a rich new way to observe functional changes in brain metabolism.

  12. Detecting and estimating head motion in brain PET acquisitions using raw time-of-flight PET data.

    PubMed

    Schleyer, P J; Dunn, J T; Reeves, S; Brownings, S; Marsden, P K; Thielemans, K

    2015-08-21

    Head motion during brain PET imaging is not uncommon and can negatively affect image quality. Motion correction techniques typically either use hardware to prospectively measure head motion, or they divide the acquisition into short fixed-frames and then align and combine these to produce a motion free image. The aim of this work was to retrospectively detect when motion occurred in PET data without the use of motion detection hardware, and then align the frames defined by these motion occurrences. We describe two methods that use either principal component analysis or the motion induced spatial displacements over time to detect motion in raw time-of-flight PET data. The points in time of motion then define the temporal boundaries of frames which are reconstructed without attenuation correction, aligned and combined. Phantom and [18F]-Fallypride patient acquisitions were used to validate and evaluate these approaches, which were compared with motion estimation using 60 s fixed-frames. Both methods identified all motion occurrences in phantom data, and unlike the fixed-frame approach did not exhibit intra-frame motion. With patient acquisitions, images corrected with the motion detection methods increased the average image sharpness by the same amount as the fixed-frame approach, but reduced the number of reconstructions and registrations by a factor of 3.4 on average. Detecting head motion in raw PET data alone is possible, allowing retrospective motion estimation of any listmode brain PET acquisition without additional hardware, subsequently decreasing data processing and potentially reducing intra-frame motion.

  13. Changes in topological organization of functional PET brain network with normal aging.

    PubMed

    Liu, Zhiliang; Ke, Lining; Liu, Huafeng; Huang, Wenhua; Hu, Zhenghui

    2014-01-01

    Recent studies about brain network have suggested that normal aging is associated with alterations in coordinated patterns of the large-scale brain functional and structural systems. However, age-related changes in functional networks constructed via positron emission tomography (PET) data are still barely understood. Here, we constructed functional brain networks composed of 90 regions in younger (mean age 36.5 years) and older (mean age 56.3 years) age groups with PET data. 113 younger and 110 older healthy individuals were separately selected for two age groups, from a physical examination database. Corresponding brain functional networks of the two groups were constructed by thresholding average cerebral glucose metabolism correlation matrices of 90 regions and analysed using graph theoretical approaches. Although both groups showed normal small-world architecture in the PET networks, increased clustering and decreased efficiency were found in older subjects, implying a degeneration process that brain system shifts from a small-world network to regular one along with normal aging. Moreover, normal senescence was related to changed nodal centralities predominantly in association and paralimbic cortex regions, e.g. increasing in orbitofrontal cortex (middle) and decreasing in left hippocampus. Additionally, the older networks were about equally as robust to random failures as younger counterpart, but more vulnerable against targeted attacks. Finally, methods in the construction of the PET networks revealed reasonable robustness. Our findings enhanced the understanding about the topological principles of PET networks and changes related to normal aging.

  14. Changes in Topological Organization of Functional PET Brain Network with Normal Aging

    PubMed Central

    Liu, Huafeng; Huang, Wenhua; Hu, Zhenghui

    2014-01-01

    Recent studies about brain network have suggested that normal aging is associated with alterations in coordinated patterns of the large-scale brain functional and structural systems. However, age-related changes in functional networks constructed via positron emission tomography (PET) data are still barely understood. Here, we constructed functional brain networks composed of regions in younger (mean age years) and older (mean age years) age groups with PET data. younger and older healthy individuals were separately selected for two age groups, from a physical examination database. Corresponding brain functional networks of the two groups were constructed by thresholding average cerebral glucose metabolism correlation matrices of regions and analysed using graph theoretical approaches. Although both groups showed normal small-world architecture in the PET networks, increased clustering and decreased efficiency were found in older subjects, implying a degeneration process that brain system shifts from a small-world network to regular one along with normal aging. Moreover, normal senescence was related to changed nodal centralities predominantly in association and paralimbic cortex regions, e.g. increasing in orbitofrontal cortex (middle) and decreasing in left hippocampus. Additionally, the older networks were about equally as robust to random failures as younger counterpart, but more vulnerable against targeted attacks. Finally, methods in the construction of the PET networks revealed reasonable robustness. Our findings enhanced the understanding about the topological principles of PET networks and changes related to normal aging. PMID:24586370

  15. Effect of Cyclosporin A on the Uptake of D3-Selective PET Radiotracers in Rat Brain

    PubMed Central

    Tu, Zhude; Li, Shihong; Xu, Jinbin; Chu, Wenhua; Jones, Lynne A.; Luedtke, Robert R.; Mach, Robert H.

    2011-01-01

    Introduction Four benzamide analogs having a high affinity and selectivity for D3 versus D2 receptors were radiolabeled with 11C or 18F for in vivo evaluation. Methods Precursors were synthesized and the four D3 selective benzamide analogs were radiolabeled. The tissue distribution and brain uptake of the four compounds were evaluated in control rats and rats pretreated with cyclosporin A, a modulator of P-glycoprotein and an inhibitor of other ABC efflux transporters that contribute to the blood brain barrier. MicroPET imaging was carried out for [11C]6 in a control and a cyclosporin A pre-treated rat. Results All four compounds showed low brain uptake in control rats at 5 and 30 min post-injection; despite recently reported rat behavioral studies conducted on analogs 6 (WC-10) and 7 (WC-44). Following administration of cyclosporin A, increased brain uptake was observed with all four PET radiotracers at both 5 and 30 min post-i.v. injection. An increase in brain uptake following modulation/inhibition of the ABC transporters was also observed in the microPET study. Conclusions These data suggest that D3 selective conformationally-flexible benzamide analogs which contain a N-2-methoxyphenylpiperazine moiety are substrates for P-glycoprotein or other ABC transporters expressed at the blood-brain barrier, and that PET radiotracers containing this pharmacophore may display low brain uptake in rodents due to the action of these efflux transporters. PMID:21718948

  16. Global cerebral glucose utilization is independent of brain size: a PET Study

    SciTech Connect

    Hatazawa, J.; Brooks, R.A.; Di Chiro, G.; Campbell, G.

    1987-07-01

    Cerebral glucose metabolic rates were measured in 80 normal volunteers by studying the uptake of (/sup 18/F)deoxyglucose with positron emission tomography (PET), using three PET scanners. A brain size index was determined from the PET images using either length-width or area measurements of the brain at a standard level. There was a significant negative correlation between glucose metabolism per unit volume and brain size that was well described by an inverse functional relationship, implying that the total glucose consumption of the brain is approximately constant. Analyses of men versus women revealed no sex differences in total brain glucose consumption, although there were differences in brain size and in glucose metabolism per unit volume. Similarly there was no significant correlation of total brain glucose consumption with age. The variation with brain size accounted for 46% of the logarithmic intersubject metabolic variance. When comparing global metabolic rates in different subjects, multiplying the rates by a brain size index has the dual advantage of correcting for differences related to brain size and correcting for differences in cerebrospinal fluid volume.

  17. Simultaneous PET-MRI reveals brain function in activated and resting state on metabolic, hemodynamic and multiple temporal scales.

    PubMed

    Wehrl, Hans F; Hossain, Mosaddek; Lankes, Konrad; Liu, Chih-Chieh; Bezrukov, Ilja; Martirosian, Petros; Schick, Fritz; Reischl, Gerald; Pichler, Bernd J

    2013-09-01

    Combined positron emission tomography (PET) and magnetic resonance imaging (MRI) is a new tool to study functional processes in the brain. Here we study brain function in response to a barrel-field stimulus simultaneously using PET, which traces changes in glucose metabolism on a slow time scale, and functional MRI (fMRI), which assesses fast vascular and oxygenation changes during activation. We found spatial and quantitative discrepancies between the PET and the fMRI activation data. The functional connectivity of the rat brain was assessed by both modalities: the fMRI approach determined a total of nine known neural networks, whereas the PET method identified seven glucose metabolism-related networks. These results demonstrate the feasibility of combined PET-MRI for the simultaneous study of the brain at activation and rest, revealing comprehensive and complementary information to further decode brain function and brain networks.

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

    NASA Astrophysics Data System (ADS)

    Jonasson, L. S.; Axelsson, J.; Riklund, K.; Boraxbekk, C. J.

    2017-07-01

    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 resolution modeling provided the most accurate data. For striatum, the BP changed by 0.08% for every 1% volume change, but for smaller volumes such as the posterior caudate the artificial change in BP was as high as 0.7% per 1% volume change. A simple gross correction for striatal volume is unsatisfactory, as the amplitude of the PVE on the BP differs depending on where in the striatum the change occurred. Therefore, to correctly interpret age-related longitudinal changes in the BP, we must account for volumetric changes also within a structure, rather than across the whole volume. The present 3D-printing technology, combined with the wall removal method, can be implemented to gain knowledge about the predictable bias introduced by the PVE differences in uptake regions of varying shape.

  19. 5-HT Radioligands for Human Brain Imaging With PET and SPECT

    PubMed Central

    Paterson, Louise M.; Kornum, Birgitte R.; Nutt, David J.; Pike, Victor W.; Knudsen, Gitte M.

    2014-01-01

    The serotonergic system plays a key modulatory role in the brain and is the target for many drug treatments for brain disorders either through reuptake blockade or via interactions at the 14 subtypes of 5-HT receptors. This review provides the history and current status of radioligands used for positron emission tomography (PET) and single photon emission computerized tomography (SPECT) imaging of human brain serotonin (5-HT) receptors, the 5-HT transporter (SERT), and 5-HT synthesis rate. Currently available radioligands for in vivo brain imaging of the 5-HT system in humans include antagonists for the 5-HT1A, 5-HT1B, 5-HT2A, and 5-HT4 receptors, and for SERT. Here we describe the evolution of these radioligands, along with the attempts made to develop radioligands for additional serotonergic targets. We describe the properties needed for a radioligand to become successful and the main caveats. The success of a PET or SPECT radioligand can ultimately be assessed by its frequency of use, its utility in humans, and the number of research sites using it relative to its invention date, and so these aspects are also covered. In conclusion, the development of PET and SPECT radioligands to image serotonergic targets is of high interest, and successful evaluation in humans is leading to invaluable insight into normal and abnormal brain function, emphasizing the need for continued development of both SPECT and PET radioligands for human brain imaging. PMID:21674551

  20. MRI-guided brain PET image filtering and partial volume correction

    NASA Astrophysics Data System (ADS)

    Yan, Jianhua; Chu-Shern Lim, Jason; Townsend, David W.

    2015-02-01

    Positron emission tomography (PET) image quantification is a challenging problem due to limited spatial resolution of acquired data and the resulting partial volume effects (PVE), which depend on the size of the structure studied in relation to the spatial resolution and which may lead to over or underestimation of the true tissue tracer concentration. In addition, it is usually necessary to perform image smoothing either during image reconstruction or afterwards to achieve a reasonable signal-to-noise ratio. Typically, an isotropic Gaussian filtering (GF) is used for this purpose. However, the noise suppression is at the cost of deteriorating spatial resolution. As hybrid imaging devices such as PET/MRI have become available, the complementary information derived from high definition morphologic images could be used to improve the quality of PET images. In this study, first of all, we propose an MRI-guided PET filtering method by adapting a recently proposed local linear model and then incorporate PVE into the model to get a new partial volume correction (PVC) method without parcellation of MRI. In addition, both the new filtering and PVC are voxel-wise non-iterative methods. The performance of the proposed methods were investigated with simulated dynamic FDG brain dataset and 18F-FDG brain data of a cervical cancer patient acquired with a simultaneous hybrid PET/MR scanner. The initial simulation results demonstrated that MRI-guided PET image filtering can produce less noisy images than traditional GF and bias and coefficient of variation can be further reduced by MRI-guided PET PVC. Moreover, structures can be much better delineated in MRI-guided PET PVC for real brain data.

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

    PubMed

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

    2017-02-23

    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 ATACpatientBone (air and tissue from the atlas with patient bone), and PET with ATACboneless (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 < .001). The results were patient dependent (range, -9.3% to 0.57%) and VOI dependent (range, -5.9 to -2.2). In addition, when bone was not included for AC, the overall difference of PET with ATACboneless (-9.4% ± 3.7) was significantly worse than that of PET with ATAC (-4.0% ± 3.2) (P < .001). Finally, when patient bone was used for AC instead of atlas bone, the overall difference of PET with ATACpatientBone (-1.5% ± 1.5) improved over that of PET with ATAC (-4.0% ± 3.2) (P < .001). Conclusion ATAC in 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

  2. Segmentation of brain PET-CT images based on adaptive use of complementary information

    NASA Astrophysics Data System (ADS)

    Xia, Yong; Wen, Lingfeng; Eberl, Stefan; Fulham, Michael; Feng, Dagan

    2009-02-01

    Dual modality PET-CT imaging provides aligned anatomical (CT) and functional (PET) images in a single scanning session, which can potentially be used to improve image segmentation of PET-CT data. The ability to distinguish structures for segmentation is a function of structure and modality and varies across voxels. Thus optimal contribution of a particular modality to segmentation is spatially variant. Existing segmentation algorithms, however, seldom account for this characteristic of PET-CT data and the results using these algorithms are not optimal. In this study, we propose a relative discrimination index (RDI) to characterize the relative abilities of PET and CT to correctly classify each voxel into the correct structure for segmentation. The definition of RDI is based on the information entropy of the probability distribution of the voxel's class label. If the class label derived from CT data for a particular voxel has more certainty than that derived from PET data, the corresponding RDI will have a higher value. We applied the RDI matrix to balance adaptively the contributions of PET and CT data to segmentation of brain PET-CT images on a voxel-by-voxel basis, with the aim to give the modality with higher discriminatory power a larger weight. The resultant segmentation approach is distinguished from traditional approaches by its innovative and adaptive use of the dual-modality information. We compared our approach to the non-RDI version and two commonly used PET-only based segmentation algorithms for simulation and clinical data. Our results show that the RDI matrix markedly improved PET-CT image segmentation.

  3. Concordance between brain (18)F-FDG PET and cerebrospinal fluid biomarkers in diagnosing Alzheimer's disease.

    PubMed

    Rubí, S; Noguera, A; Tarongí, S; Oporto, M; García, A; Vico, H; Espino, A; Picado, M J; Mas, A; Peña, C; Amer, G

    2017-06-20

    Cortical posterior hypometabolism on PET imaging with (18)F-FDG (FDG-PET), and altered levels of Aß1-42 peptide, total Tau (tTau) and phosphorylated Tau (pTau) proteins in cerebrospinal fluid (CSF) are established diagnostic biomarkers in Alzheimer's disease (AD). An evaluation has been made of the concordance and relationship between the results of FDG-PET and CSF biomarkers in symptomatic patients with suspected AD. A retrospective review was carried out on 120 patients with cognitive impairment referred to our Cognitive Neurology Unit, and who were evaluated by brain FDG-PET and a lumbar puncture for CSF biomarkers. In order to calculate their Kappa coefficient of concordance, the result of the FDG-PET and the set of the three CSF biomarkers in each patient was classified as normal, inconclusive, or AD-compatible. The relationship between the results of both methods was further assessed using logistic regression analysis, including the Aß1-42, tTau and pTau levels as quantitative predictors, and the FDG-PET result as the dependent variable. The weighted Kappa coefficient between FDG-PET and CSF biomarkers was 0.46 (95% CI: 0.35-0.57). Logistic regression analysis showed that the Aß1-42 and tTau values together were capable of discriminating an FDG-PET result metabolically suggestive of AD from one non-suggestive of AD, with a 91% sensitivity and 93% specificity at the cut-off line Aß1-42=44+1.3×tTau. The level of concordance between FDG-PET and CSF biomarkers was moderate, indicating their complementary value in diagnosing AD. The Aß1-42 and tTau levels in CSF help to predict the patient FDG-PET cortical metabolic status. Copyright © 2017 Elsevier España, S.L.U. y SEMNIM. All rights reserved.

  4. Proposed helmet PET geometries with add-on detectors for high sensitivity brain imaging.

    PubMed

    Tashima, Hideaki; Yamaya, Taiga

    2016-10-07

    For dedicated brain PET, we can significantly improve sensitivity for the cerebrum region by arranging detectors in a compact hemisphere. The geometrical sensitivity for the top region of the hemisphere is increased compared with conventional cylindrical PET consisting of the same number of detectors. However, the geometrical sensitivity at the center region of the hemisphere is still low because the bottom edge of the field-of-view is open, the same as for the cylindrical PET. In this paper, we proposed a helmet PET with add-on detectors for high sensitivity brain PET imaging for both center and top regions. The key point is the add-on detectors covering some portion of the spherical surface in addition to the hemisphere. As the location of the add-on detectors, we proposed three choices: a chin detector, ear detectors, and a neck detector. For example, the geometrical sensitivity for the region-of-interest at the center was increased by 200% by adding the chin detector which increased the size by 12% of the size of the hemisphere detector. The other add-on detectors gave almost the same increased sensitivity effect as the chin detector did. Compared with standard whole-body-cylindrical PET, the proposed geometries can achieve 2.6 times higher sensitivity for brain region even with less than 1/4 detectors. In addition, we conducted imaging simulations for geometries with a diameter of 250 mm and with high resolution depth-of-interaction detectors. The simulation results showed that the proposed geometries increased image quality, and all of the add-on detectors were equivalently effective. In conclusion, the proposed geometries have high potential for widespread applications in high-sensitivity, high-resolution, and low-cost brain PET imaging.

  5. Proposed helmet PET geometries with add-on detectors for high sensitivity brain imaging

    NASA Astrophysics Data System (ADS)

    Tashima, Hideaki; Yamaya, Taiga

    2016-10-01

    For dedicated brain PET, we can significantly improve sensitivity for the cerebrum region by arranging detectors in a compact hemisphere. The geometrical sensitivity for the top region of the hemisphere is increased compared with conventional cylindrical PET consisting of the same number of detectors. However, the geometrical sensitivity at the center region of the hemisphere is still low because the bottom edge of the field-of-view is open, the same as for the cylindrical PET. In this paper, we proposed a helmet PET with add-on detectors for high sensitivity brain PET imaging for both center and top regions. The key point is the add-on detectors covering some portion of the spherical surface in addition to the hemisphere. As the location of the add-on detectors, we proposed three choices: a chin detector, ear detectors, and a neck detector. For example, the geometrical sensitivity for the region-of-interest at the center was increased by 200% by adding the chin detector which increased the size by 12% of the size of the hemisphere detector. The other add-on detectors gave almost the same increased sensitivity effect as the chin detector did. Compared with standard whole-body-cylindrical PET, the proposed geometries can achieve 2.6 times higher sensitivity for brain region even with less than 1/4 detectors. In addition, we conducted imaging simulations for geometries with a diameter of 250 mm and with high resolution depth-of-interaction detectors. The simulation results showed that the proposed geometries increased image quality, and all of the add-on detectors were equivalently effective. In conclusion, the proposed geometries have high potential for widespread applications in high-sensitivity, high-resolution, and low-cost brain PET imaging.

  6. Considerations in the Development of Reversibly Binding PET Radioligands for Brain Imaging

    PubMed Central

    Pike, Victor W.

    2017-01-01

    The development of reversibly binding radioligands for imaging brain proteins in vivo, such as enzymes, neurotransmitter transporters, receptors and ion channels, with positron emission tomography (PET) is keenly sought for biomedical studies of neuropsychiatric disorders and for drug discovery and development, but is recognized as being highly challenging at the medicinal chemistry level. This article aims to compile and discuss the main considerations to be taken into account by chemists embarking on programs of radioligand development for PET imaging of brain protein targets. PMID:27087244

  7. Discovery of MK-3168: A PET Tracer for Imaging Brain Fatty Acid Amide Hydrolase

    PubMed Central

    2013-01-01

    We report herein the discovery of a fatty acid amide hydrolase (FAAH) positron emission tomography (PET) tracer. Starting from a pyrazole lead, medicinal chemistry efforts directed toward reducing lipophilicity led to the synthesis of a series of imidazole analogues. Compound 6 was chosen for further profiling due to its appropriate physical chemical properties and excellent FAAH inhibition potency across species. [11C]-6 (MK-3168) exhibited good brain uptake and FAAH-specific signal in rhesus monkeys and is a suitable PET tracer for imaging FAAH in the brain. PMID:24900701

  8. Discovery of MK-3168: A PET Tracer for Imaging Brain Fatty Acid Amide Hydrolase.

    PubMed

    Liu, Ping; Hamill, Terence G; Chioda, Marc; Chobanian, Harry; Fung, Selena; Guo, Yan; Chang, Linda; Bakshi, Raman; Hong, Qingmei; Dellureficio, James; Lin, Linus S; Abbadie, Catherine; Alexander, Jessica; Jin, Hong; Mandala, Suzanne; Shiao, Lin-Lin; Li, Wenping; Sanabria, Sandra; Williams, David; Zeng, Zhizhen; Hajdu, Richard; Jochnowitz, Nina; Rosenbach, Mark; Karanam, Bindhu; Madeira, Maria; Salituro, Gino; Powell, Joyce; Xu, Ling; Terebetski, Jenna L; Leone, Joseph F; Miller, Patricia; Cook, Jacquelynn; Holahan, Marie; Joshi, Aniket; O'Malley, Stacey; Purcell, Mona; Posavec, Diane; Chen, Tsing-Bau; Riffel, Kerry; Williams, Mangay; Hargreaves, Richard; Sullivan, Kathleen A; Nargund, Ravi P; DeVita, Robert J

    2013-06-13

    We report herein the discovery of a fatty acid amide hydrolase (FAAH) positron emission tomography (PET) tracer. Starting from a pyrazole lead, medicinal chemistry efforts directed toward reducing lipophilicity led to the synthesis of a series of imidazole analogues. Compound 6 was chosen for further profiling due to its appropriate physical chemical properties and excellent FAAH inhibition potency across species. [(11)C]-6 (MK-3168) exhibited good brain uptake and FAAH-specific signal in rhesus monkeys and is a suitable PET tracer for imaging FAAH in the brain.

  9. PET Radiotracers: crossing the blood-brain barrier and surviving metabolism

    PubMed Central

    Pike, Victor W.

    2009-01-01

    Radiotracers for imaging protein targets in living human brain with positron emission tomography (PET) are increasingly useful in clinical research and in drug development. Such radiotracers must fulfill many criteria, among which an ability to enter brain adequately and reversibly without contamination by troublesome radiometabolites is desirable for accurate measurement of the density of a target protein (e.g., neuroreceptor, transporter, enzyme or plaque). Candidate radiotracers may fail as a result of poor passive brain entry, rejection from brain by efflux transporters or undesirable metabolism. These issues are reviewed. Emerging PET radiotracers for measuring efflux transporter function, and new strategies for ameliorating radiotracer metabolism are discussed. A growing understanding of the molecular features affecting the brain penetration, metabolism and efflux transporter sensitivity of prospective radiotracers should ultimately lead to their more rational and efficient design, and also to their greater efficacy. PMID:19616318

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

    PubMed

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

    2015-11-21

    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.

  11. Advances in PET imaging of P-glycoprotein function at the blood-brain barrier.

    PubMed

    Syvänen, Stina; Eriksson, Jonas

    2013-02-20

    Efflux transporter P-glycoprotein (P-gp) at the blood-brain barrier (BBB) restricts substrate compounds from entering the brain and may thus contribute to pharmacoresistance observed in patient groups with refractory epilepsy and HIV. Altered P-gp function has also been implicated in neurodegenerative diseases such as Alzheimer's and Parkinson's disease. Positron emission tomography (PET), a molecular imaging modality, has become a promising method to study the role of P-gp at the BBB. The first PET study of P-gp function was conducted in 1998, and during the past 15 years two main categories of P-gp PET tracers have been investigated: tracers that are substrates of P-gp efflux and tracers that are inhibitors of P-gp function. PET, as a noninvasive imaging technique, allows translational research. Examples of this are preclinical investigations of P-gp function before and after administering P-gp modulating drugs, investigations in various animal and disease models, and clinical investigations regarding disease and aging. The objective of the present review is to give an overview of available PET radiotracers for studies of P-gp and to discuss how such studies can be designed. Further, the review summarizes results from PET studies of P-gp function in different central nervous system disorders.

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

    NASA Astrophysics Data System (ADS)

    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.

  13. PET Imaging of Tau Deposition in the Aging Human Brain

    DOE PAGES

    Schöll, Michael; Lockhart, Samuel N.; Schonhaut, Daniel R.; ...

    2016-03-02

    Tau pathology is a hallmark of Alzheimer’s disease (AD) but also occurs in normal cognitive aging. In this study, using the tau PET agent 18F-AV-1451, we examined retention patterns in cognitively normal older people in relation to young controls and AD patients. Age and β-amyloid (measured using PiB PET) were differentially associated with tau tracer retention in healthy aging. Older age was related to increased tracer retention in regions of the medial temporal lobe, which predicted worse episodic memory performance. PET detection of tau in other isocortical regions required the presence of cortical β-amyloid and was associated with decline inmore » global cognition. Furthermore, patterns of tracer retention corresponded well with Braak staging of neurofibrillary tau pathology. In conclusion, the present study defined patterns of tau tracer retention in normal aging in relation to age, cognition, and β-amyloid deposition.« less

  14. PET Imaging of Tau Deposition in the Aging Human Brain

    SciTech Connect

    Schöll, Michael; Lockhart, Samuel N.; Schonhaut, Daniel R.; O’Neil, James P.; Janabi, Mustafa; Ossenkoppele, Rik; Baker, Suzanne L.; Vogel, Jacob W.; Faria, Jamie; Schwimmer, Henry D.; Rabinovici, Gil D.; Jagust, William J.

    2016-03-02

    Tau pathology is a hallmark of Alzheimer’s disease (AD) but also occurs in normal cognitive aging. In this study, using the tau PET agent 18F-AV-1451, we examined retention patterns in cognitively normal older people in relation to young controls and AD patients. Age and β-amyloid (measured using PiB PET) were differentially associated with tau tracer retention in healthy aging. Older age was related to increased tracer retention in regions of the medial temporal lobe, which predicted worse episodic memory performance. PET detection of tau in other isocortical regions required the presence of cortical β-amyloid and was associated with decline in global cognition. Furthermore, patterns of tracer retention corresponded well with Braak staging of neurofibrillary tau pathology. In conclusion, the present study defined patterns of tau tracer retention in normal aging in relation to age, cognition, and β-amyloid deposition.

  15. PET Imaging of Tau Deposition in the Aging Human Brain

    PubMed Central

    Schonhaut, Daniel R.; O’Neil, James P.; Janabi, Mustafa; Ossenkoppele, Rik; Baker, Suzanne L.; Vogel, Jacob W.; Faria, Jamie; Schwimmer, Henry D.; Rabinovici, Gil D.; Jagust, William J.

    2016-01-01

    SUMMARY Tau pathology is a hallmark of Alzheimer’s disease (AD) but also occurs in normal cognitive aging. Using the tau PET agent 18F-AV-1451, we examined retention patterns in cognitively normal older people in relation to young controls and AD patients. Age and β-amyloid (measured using PiB PET) were differentially associated with tau tracer retention in healthy aging. Older age was related to increased tracer retention in regions of the medial temporal lobe, which predicted worse episodic memory performance. PET detection of tau in other isocortical regions required the presence of cortical β-amyloid, and was associated with decline in global cognition. Furthermore, patterns of tracer retention corresponded well with Braak staging of neurofibrillary tau pathology. The present study defined patterns of tau tracer retention in normal aging in relation to age, cognition, and β-amyloid deposition. PMID:26938442

  16. EANM procedure guidelines for PET brain imaging using [18F]FDG, version 2.

    PubMed

    Varrone, Andrea; Asenbaum, Susanne; Vander Borght, Thierry; Booij, Jan; Nobili, Flavio; Någren, Kjell; Darcourt, Jacques; Kapucu, Ozlem L; Tatsch, Klaus; Bartenstein, Peter; Van Laere, Koen

    2009-12-01

    These guidelines summarize the current views of the European Association of Nuclear Medicine Neuroimaging Committee (ENC). The purpose of the guidelines is to assist nuclear medicine practitioners in making recommendations, performing, interpreting, and reporting the results of fluorine-18 fluoro-2-deoxyglucose ([(18)F]FDG) PET imaging of the brain. The aim is to help achieve a high standard of FDG imaging, which will increase the diagnostic impact of this technique in neurological and psychiatric practice. The present document replaces a former version of the guidelines that were published in 2002 [1] and includes an update in the light of advances in PET technology, the introduction of hybrid PET/CT systems and the broadening clinical indications for FDG brain imaging. These guidelines are intended to present information specifically adapted for European practice. The information provided should be taken in the context of local conditions and regulations.

  17. ACR-ASNR Practice Parameter for Brain PET/CT Imaging Dementia.

    PubMed

    Frey, Kirk A; Lodge, Martin A; Meltzer, Carolyn Cidis; Peller, Patrick J; Wong, Terence Z; Hess, Christopher P; Petrella, Jeffrey R; Sair, Haris I; Subramaniam, Rathan M

    2016-02-01

    This practice parameter is for both FDG and amyloid brain PET or PET/computed tomography (CT) for patients with cognitive decline, and has been developed collaboratively by the American College of Radiology (ACR) and the American Society for Neuroradiology (ASNR). It is estimated that the number of people with dementia, 36.5 million worldwide in 2010, will increase to 65.7 million in 2030 and to 115 million in 2050. Four primary neurodegenerative etiologies of dementia have been defined: Alzheimer disease (AD), vascular dementia, frontotemporal dementia (FTD), and dementia with Lewy bodies (DLB). Alzheimer disease is the most common form of dementia, accounting for approximately 60%-80% of all cases. Indications for FDG and amyloid brain PET and qualifications for personnel are discussed in this practice parameter.

  18. Role of (18)F-FDG PET/CT in primary brain lymphoma.

    PubMed

    de-Bonilla-Damiá, Á; Fernández-López, R; Capote-Huelva, F J; de la Cruz-Vicente, F; Egea-Guerrero, J J; Borrego-Dorado, I

    To study the usefulness of (18)F-FDG PET/CT in the initial evaluation and in the response assessment in primary brain lymphoma. A retrospective analysis was carried out on 18 patients diagnosed with primary brain lymphoma, a histological subtype of diffuse large B-cell lymphoma, on whom an initial (18)F-FDG PET/CT and MRI was performed, with 7 of the cases being analysed after the completion of treatment in order to assess response and clinical follow up. Initial (18)F-FDG PET/CT showed 26 hypermetabolic foci, whereas 46 lesions were detected by MRI. The average SUV maximum of the lesions was 17.56 with T/N 3.55. The concordance of both tests for identifying the same number of lesions was moderate, obtaining a kappa index of 0.395 (P<.001). In the evaluation of treatment, MRI identified 16 lesions compared to 7 pathological accumulations observed by (18)F-FDG PET/CT. The concordance of both tests to assess type of response to treatment was moderate (kappa index 0.41) (P=.04). In both the initial evaluation and the assessment of the response to treatment, PET/CT led to a change strategy in 22% of patients who had lesions outside the cerebral parenchyma. MRI appears to be the method of choice for detecting brain disease in patients with primary brain lymphoma, whereas (18)F-FDG PET/CT seems to play a relevant role in the assessment of extra-cerebral disease. Copyright © 2017 Elsevier España, S.L.U. y SEMNIM. All rights reserved.

  19. Brain Mapping of Language and Auditory Perception in High-Functioning Autistic Adults: A PET Study.

    ERIC Educational Resources Information Center

    Muller, R-A.; Behen, M. E.; Rothermel, R. D.; Chugani, D. C.; Muzik, O.; Mangner, T. J.; Chugani, H. T.

    1999-01-01

    A study used positron emission tomography (PET) to study patterns of brain activation during auditory processing in five high-functioning adults with autism. Results found that participants showed reversed hemispheric dominance during the verbal auditory stimulation and reduced activation of the auditory cortex and cerebellum. (CR)

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

    PubMed

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

    2017-05-16

    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.

  1. Mapping human brain fatty acid amide hydrolase activity with PET

    PubMed Central

    Rusjan, Pablo M; Wilson, Alan A; Mizrahi, Romina; Boileau, Isabelle; Chavez, Sofia E; Lobaugh, Nancy J; Kish, Stephen J; Houle, Sylvain; Tong, Junchao

    2013-01-01

    Endocannabinoid tone has recently been implicated in a number of prevalent neuropsychiatric conditions. [11C]CURB is the first available positron emission tomography (PET) radiotracer for imaging fatty acid amide hydrolase (FAAH), the enzyme which metabolizes the prominent endocannabinoid anandamide. Here, we sought to determine the most suitable kinetic modeling approach for quantifying [11C]CURB that binds selectively to FAAH. Six healthy volunteers were scanned with arterial blood sampling for 90 minutes. Kinetic parameters were estimated regionally using a one-tissue compartment model (TCM), a 2-TCM with and without irreversible trapping, and an irreversible 3-TCM. The 2-TCM with irreversible trapping provided the best identifiability of PET outcome measures among the approaches studied (coefficient of variation (COV) of the net influx constant Ki and the composite parameter λk3 (λ=K1/k2) <5%, and COV(k3)<10%). Reducing scan time to 60 minutes did not compromise the identifiability of rate constants. Arterial spin labeling measures of regional cerebral blood flow were only slightly correlated with Ki, but not with k3 or λk3. Our data suggest that λk3 is sensitive to changes in FAAH activity, therefore, optimal for PET quantification of FAAH activities with [11C]CURB. Simulations showed that [11C]CURB binding in healthy subjects is far from a flow-limited uptake. PMID:23211960

  2. Validation of true low-dose 18F-FDG PET of the brain

    PubMed Central

    Fällmar, David; Lilja, Johan; Kilander, Lena; Danfors, Torsten; Lubberink, Mark; Larsson, Elna-Marie; Sörensen, Jens

    2016-01-01

    The dosage of 18F-FDG must be sufficient to ensure adequate PET image quality. For younger patients and research controls, the lowest possible radiation dose should be used. The purpose of this study was to find a protocol for FDG-PET of the brain with reduced radiation dose and preserved quantitative characteristics. Eight patients with neurodegenerative disorders and nine controls (n=17) underwent FDG-PET/CT twice on separate occasions, first with normal-dose (3 MBq/kg), and second with low-dose (0.75 MBq/kg, 25% of the original). Five additional controls (total n=22) underwent FDG-PET twice, using normal-dose and ultra-low-dose (0.3 MBq/kg, 10% of original). All subjects underwent MRI. Ten-minute summation images were spatially normalized and intensity normalized. Regional standard uptake value ratios (SUV-r) were calculated using an automated atlas. SUV-r values from the normal- and low-dose images were compared pairwise. No clinically significant bias was found in any of the three groups. The mean absolute difference in regional SUV-r values was 0.015 (1.32%) in controls and 0.019 (1.67%) in patients. The ultra-low-dose protocol produced a slightly higher mean difference of 0.023 (2.10%). The main conclusion is that 0.75 MBq/kg (56 MBq for a 75-kg subject) is a sufficient FDG dose for evaluating regional SUV-ratios in brain PET scans in adults with or without neurodegenerative disease, resulting in a reduction of total PET/CT effective dose from 4.54 to 1.15 mSv. The ultra-low-dose (0.5 mSv) could be useful in research studies requiring serial PET in healthy controls or children. PMID:27766185

  3. Validation of true low-dose (18)F-FDG PET of the brain.

    PubMed

    Fällmar, David; Lilja, Johan; Kilander, Lena; Danfors, Torsten; Lubberink, Mark; Larsson, Elna-Marie; Sörensen, Jens

    2016-01-01

    The dosage of (18)F-FDG must be sufficient to ensure adequate PET image quality. For younger patients and research controls, the lowest possible radiation dose should be used. The purpose of this study was to find a protocol for FDG-PET of the brain with reduced radiation dose and preserved quantitative characteristics. Eight patients with neurodegenerative disorders and nine controls (n=17) underwent FDG-PET/CT twice on separate occasions, first with normal-dose (3 MBq/kg), and second with low-dose (0.75 MBq/kg, 25% of the original). Five additional controls (total n=22) underwent FDG-PET twice, using normal-dose and ultra-low-dose (0.3 MBq/kg, 10% of original). All subjects underwent MRI. Ten-minute summation images were spatially normalized and intensity normalized. Regional standard uptake value ratios (SUV-r) were calculated using an automated atlas. SUV-r values from the normal- and low-dose images were compared pairwise. No clinically significant bias was found in any of the three groups. The mean absolute difference in regional SUV-r values was 0.015 (1.32%) in controls and 0.019 (1.67%) in patients. The ultra-low-dose protocol produced a slightly higher mean difference of 0.023 (2.10%). The main conclusion is that 0.75 MBq/kg (56 MBq for a 75-kg subject) is a sufficient FDG dose for evaluating regional SUV-ratios in brain PET scans in adults with or without neurodegenerative disease, resulting in a reduction of total PET/CT effective dose from 4.54 to 1.15 mSv. The ultra-low-dose (0.5 mSv) could be useful in research studies requiring serial PET in healthy controls or children.

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

    NASA Astrophysics Data System (ADS)

    González, Antonio J.; Majewski, Stan; Sánchez, Filomeno; Aussenhofer, Sebastian; Aguilar, Albert; Conde, Pablo; Hernández, Liczandro; Vidal, Luis F.; Pani, Roberto; Bettiol, Marco; Fabbri, Andrea; Bert, Julien; Visvikis, Dimitris; Jackson, Carl; Murphy, John; O'Neill, Kevin; Benlloch, Jose M.

    2016-05-01

    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 mm2 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%.

  5. Motion compensation for brain PET imaging using wireless MR active markers in simultaneous PET-MR: phantom and non-human primate studies.

    PubMed

    Huang, Chuan; Ackerman, Jerome L; Petibon, Yoann; Normandin, Marc D; Brady, Thomas J; El Fakhri, Georges; Ouyang, Jinsong

    2014-05-01

    Brain PET scanning plays an important role in the diagnosis, prognostication and monitoring of many brain diseases. Motion artifacts from head motion are one of the major hurdles in brain PET. In this work, we propose to use wireless MR active markers to track head motion in real time during a simultaneous PET-MR brain scan and incorporate the motion measured by the markers in the listmode PET reconstruction. Several wireless MR active markers and a dedicated fast MR tracking pulse sequence module were built. Data were acquired on an ACR Flangeless PET phantom with multiple spheres and a non-human primate with and without motion. Motions of the phantom and monkey's head were measured with the wireless markers using a dedicated MR tracking sequence module. The motion PET data were reconstructed using list-mode reconstruction with and without motion correction. Static reference was used as gold standard for quantitative analysis. The motion artifacts, which were prominent on the images without motion correction, were eliminated by the wireless marker based motion correction in both the phantom and monkey experiments. Quantitative analysis was performed on the phantom motion data from 24 independent noise realizations. The reduction of bias of sphere-to-background PET contrast by active marker based motion correction ranges from 26% to 64% and 17% to 25% for hot (i.e., radioactive) and cold (i.e., non-radioactive) spheres, respectively. The motion correction improved the channelized Hotelling observer signal-to-noise ratio of the spheres by 1.2 to 6.9 depending on their locations and sizes. The proposed wireless MR active marker based motion correction technique removes the motion artifacts in the reconstructed PET images and yields accurate quantitative values. Copyright © 2014 Elsevier Inc. All rights reserved.

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

    SciTech Connect

    Mukherjee, J. M. Lindsay, C.; King, M. A.; Licho, R.; Mukherjee, A.; Olivier, P.; Shao, L.

    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

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

    PubMed

    Mukherjee, J M; Lindsay, C; Mukherjee, A; Olivier, P; Shao, L; King, M A; Licho, R

    2016-05-01

    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. 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. 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 not susceptible to motion

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

    PubMed Central

    Mukherjee, J. M.; Lindsay, C.; Mukherjee, A.; Olivier, P.; Shao, L.; King, M. A.; Licho, R.

    2016-01-01

    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

  9. Scatter correction for large non-human primate brain imaging using microPET

    NASA Astrophysics Data System (ADS)

    Naidoo-Variawa, S.; Lehnert, W.; Banati, R. B.; Meikle, S. R.

    2011-04-01

    The baboon is well suited to pre-clinical evaluation of novel radioligands for positron emission tomography (PET). We have previously demonstrated the feasibility of using a high resolution animal PET scanner for this application in the baboon brain. However, the non-homogenous distribution of tissue density within the head may give rise to photon scattering effects that reduce contrast and compromise quantitative accuracy. In this study, we investigated the magnitude and distribution of scatter contributing to the final reconstructed image and its variability throughout the baboon brain using phantoms and Monte Carlo simulated data. The scatter fraction is measured up to 36% at the centre of the brain for a wide energy window (350-650 keV) and 19% for a narrow (450-650 keV) window. We observed less than 3% variation in the scatter fraction throughout the brain and found that scattered events arising from radioactivity outside the field of view contribute less than 1% of measured coincidences. In a contrast phantom, scatter and attenuation correction improved contrast recovery compared with attenuation correction on its own and reduced bias to less than 10% at the expense of the reduced signal-to-noise ratio. We conclude that scatter correction is a necessary step for ensuring high quality measurements of the radiotracer distribution in the baboon brain with a microPET scanner, while it is not necessary to model out of field of view scatter or a spatially variant scatter function.

  10. Short-Term Practice Effects and Brain Hypometabolism: Preliminary Data from an FDG PET Study.

    PubMed

    Duff, Kevin; Horn, Kevin P; Foster, Norman L; Hoffman, John M

    2015-05-01

    Practice effects are improvements in cognitive test scores due to repeated exposure to the same tests. Typically viewed as error, short-term practice effects have been shown to provide valuable clinical information about diagnosis, prognosis, and treatment outcomes in older patients with mild cognitive impairments. This study examined short-term practice effects across one week and brain hypometabolism on fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) in 25 older adults (15 intact, 10 Mild Cognitive Impairment). Averaged cerebral brain metabolism on FDG PET was correlated with multiple cognitive scores at baseline in those with Mild Cognitive Impairment, and short-term practice effects accounted for additional variance in these same subjects. The relationship between brain metabolism and cognition (either at baseline or practice effects) was minimal in the intact individuals. Although needing replication in larger samples, short-term practice effects on tests of executive functioning and memory may provide valuable information about biomarkers of Alzheimer's disease.

  11. Response to Deep Brain Stimulation in Three Brain Targets with Implications in Mental Disorders: A PET Study in Rats

    PubMed Central

    Casquero-Veiga, Marta; Hadar, Ravit; Pascau, Javier; Winter, Christine; Desco, Manuel; Soto-Montenegro, María Luisa

    2016-01-01

    Objective To investigate metabolic changes in brain networks by deep brain stimulation (DBS) of the medial prefrontal cortex (mPFC), nucleus accumbens (NAcc) and dorsomedial thalamus (DM) using positron emission tomography (PET) in naïve rats. Methods 43 male Wistar rats underwent stereotactic surgery and concentric bipolar platinum-iridium electrodes were bilaterally implanted into one of the three brain sites. [18F]-fluoro-2-deoxy-glucose-PET (18FDG-PET) and computed tomography (CT) scans were performed at the 7th (without DBS) and 9th day (with DBS) after surgery. Stimulation period matched tracer uptake period. Images were acquired with a small-animal PET-CT scanner. Differences in glucose uptake between groups were assessed with Statistical Parametric Mapping. Results DBS induced site-specific metabolic changes, although a common increased metabolic activity in the piriform cortex was found for the three brain targets. mPFC-DBS increased metabolic activity in the striatum, temporal and amygdala, and reduced it in the cerebellum, brainstem (BS) and periaqueductal gray matter (PAG). NAcc-DBS increased metabolic activity in the subiculum and olfactory bulb, and decreased it in the BS, PAG, septum and hypothalamus. DM-DBS increased metabolic activity in the striatum, NAcc and thalamus and decreased it in the temporal and cingulate cortex. Conclusions DBS induced significant changes in 18FDG uptake in brain regions associated with the basal ganglia-thalamo-cortical circuitry. Stimulation of mPFC, NAcc and DM induced different patterns of 18FDG uptake despite interacting with the same circuitries. This may have important implications to DBS research suggesting individualized target selection according to specific neural modulatory requirements. PMID:28033356

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

    NASA Astrophysics Data System (ADS)

    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

  13. Quantification of F-18 FDG PET images in temporal lobe epilepsy patients using probabilistic brain atlas.

    PubMed

    Kang, K W; Lee, D S; Cho, J H; Lee, J S; Yeo, J S; Lee, S K; Chung, J K; Lee, M C

    2001-07-01

    A probabilistic atlas of the human brain (Statistical Probabilistic Anatomical Maps: SPAM) was developed by the international consortium for brain mapping (ICBM). It is a good frame for calculating volume of interest (VOI) in many fields of brain images. After calculating the counts in VOI using the product of probability of SPAM images and counts in FDG images, asymmetric indices (AI) were calculated and used for finding epileptogenic zones in mesial temporal lobe epilepsy (mTLE). FDG PET images from 18 surgically confirmed mTLE patients and 22 age-matched controls were spatially normalized to the average brain MRI template of ICBM. Counts from normalized PET images were multiplied with the probability of 12 VOIs from SPAM images in both temporal lobes. Finally AI were calculated on each pair of VOIs, and compared with visual assessment. If AI of mTLE patients were not within 2.9 standard deviation from those of normal control group (P < 0.008; Bonferroni correction for P < 0.05), epileptogenic zones were considered to be found successfully. The counts of VOIs in the normal control group were symmetric (AI < 4.3%, paired t test P > 0.05) except for those of the inferior temporal gyrus (P < 0.001). By AIs in six pairs of VOIs, PET in mTLE had deficit on one side (P < 0.05). Lateralization was correct in only 14/18 of patients by AI, but 17/18 were consistent with visual inspection. In three patients with normal AI, PET images were symmetric on visual inspection. The asymmetric indices obtained by taking the product of the statistical probability anatomical map and FDG PET, correlated well with visual assessment in mTLE patients. SPAM is useful for the quantification of VOIs in functional images.

  14. Diagnostic Value of 68Ga PSMA-11 PET/CT Imaging of Brain Tumors-Preliminary Analysis.

    PubMed

    Sasikumar, Arun; Joy, Ajith; Pillai, M R A; Nanabala, Raviteja; Anees K, Muhammed; Jayaprakash, P G; Madhavan, Jayaprakash; Nair, Suresh

    2017-01-01

    To evaluate the feasibility of using Ga PSMA-11 PET/CT for imaging brain lesions and its comparison with F-FDG. Ten patients with brain lesions were included in the study. Five patients were treated cases of glioblastoma with suspected recurrence. F-FDG and Ga PSMA-11 brain scans were done for these patients. Five patients were sent for assessing the nature (primary lesion/metastasis) of space occupying lesion in brain. They underwent whole body F-FDG PET/CT scan and a primary site elsewhere in the body was ruled out. Subsequently they underwent Ga PSMA-11 brain PET/CT imaging. Target to background ratios (TBR) for the brain lesions were calculated using contralateral cerebellar uptake as background. In five treated cases of glioblastoma with suspected recurrence the findings of Ga PSMA-11 PET/CT showed good correlation with that of F-FDG PET/CT scan. Compared to the F-FDG, Ga PSMA-11 PET/CT showed better visualization of the recurrent lesion (presence/absence) owing to its significantly high TBR. Among the five cases evaluated for lesion characterization glioma and atypical meningioma patients showed higher SUVmax in the lesion with Ga PSMA-11 than with F-FDG and converse in cases of lymphoma. TBR was better with Ga PSMA PET/CT in all cases. Ga PSMA-11 PET/CT brain imaging is a potentially useful imaging tool in the evaluation of brain lesions. Absence of physiological uptake of Ga PSMA-11 in the normal brain parenchyma results in high TBR values and consequently better visualization of metabolically active disease in brain.

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

    NASA Astrophysics Data System (ADS)

    Olesen, Oline V.; Jørgensen, Morten R.; Paulsen, Rasmus R.; Højgaard, Liselotte; Roed, Bjarne; Larsen, Rasmus

    2010-02-01

    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 DLP projector and a CCD camera is set up on a model of the High Resolution Research Tomograph (HRRT). Methods to reconstruct 3D point clouds of simple surfaces based on phase-shifting interferometry (PSI) are demonstrated. The projector and camera are calibrated using a simple stereo vision procedure where the projector is treated as a camera. Additionally, the surface reconstructions are corrected for the non-linear projector output prior to image capture. The results are convincing and a first step toward a fully automated tracking system for measuring head motions in PET imaging.

  16. Continuous Scintillator Detector Blocks for Simultaneous Pet-Mr Imaging of the Human Brain

    NASA Astrophysics Data System (ADS)

    Rato Mendes, Pedro

    2010-04-01

    Continuous scintillator detector blocks have several advantages over pixelated designs, presenting a larger active volume and a lower cost with comparable or better energy and spatial resolutions. In this paper we describe the operation of continuous detector blocks for positron emission tomography (PET) and their suitability for multimodality imaging operating inside a magnetic resonance (MR) scanner. This detector technology is being used on a full-scale clinical scanner for human brain PET studies presently under development at Ciemat. Results will be presented on the laboratory characterization of monolithic scintillators coupled to APD matrices with ASIC readout, including images of point sources from a prototype dual-head demonstrator illustrating the potential of continuous scintillator detector blocks for high-resolution PET-MR imaging.

  17. FDG-PET imaging in mild traumatic brain injury: a critical review

    PubMed Central

    Byrnes, Kimberly R.; Wilson, Colin M.; Brabazon, Fiona; von Leden, Ramona; Jurgens, Jennifer S.; Oakes, Terrence R.; Selwyn, Reed G.

    2013-01-01

    Traumatic brain injury (TBI) affects an estimated 1.7 million people in the United States and is a contributing factor to one third of all injury related deaths annually. According to the CDC, approximately 75% of all reported TBIs are concussions or considered mild in form, although the number of unreported mild TBIs (mTBI) and patients not seeking medical attention is unknown. Currently, classification of mTBI or concussion is a clinical assessment since diagnostic imaging is typically inconclusive due to subtle, obscure, or absent changes in anatomical or physiological parameters measured using standard magnetic resonance (MR) or computed tomography (CT) imaging protocols. Molecular imaging techniques that examine functional processes within the brain, such as measurement of glucose uptake and metabolism using [18F]fluorodeoxyglucose and positron emission tomography (FDG-PET), have the ability to detect changes after mTBI. Recent technological improvements in the resolution of PET systems, the integration of PET with magnetic resonance imaging (MRI), and the availability of normal healthy human databases and commercial image analysis software contribute to the growing use of molecular imaging in basic science research and advances in clinical imaging. This review will discuss the technological considerations and limitations of FDG-PET, including differentiation between glucose uptake and glucose metabolism and the significance of these measurements. In addition, the current state of FDG-PET imaging in assessing mTBI in clinical and preclinical research will be considered. Finally, this review will provide insight into potential critical data elements and recommended standardization to improve the application of FDG-PET to mTBI research and clinical practice. PMID:24409143

  18. Development and use of a kinetic FDG-PET dataset simulated from the MNI standard brain

    NASA Astrophysics Data System (ADS)

    Schottlander, David; Guimond, Alexandre; Pan, Xiao-Bo; Brady, Michael; Declerck, Jérôme; Collins, Louis; Evans, Alan C.; Reilhac, Anthonin

    2006-03-01

    Simulated data is an important tool for evaluation of reconstruction and image processing algorithms in the frequent absence of ground truth, in-vivo data from living subjects. This is especially true in the case of dynamic PET studies, in which counting statistics of the volume can vary widely over the time-course of the acquisition. Realistic simulated data-sets which model anatomy and physiology, and make explicit the spatial and temporal image acquisition characteristics, facilitate experimentation with a wide range of the conditions anticipated in practice, and which can severely challenge algorithm performance and reliability. As a first example, we have developed a realistic dynamic FDG-PET data-set using the PET-SORTEO Monte Carlo simulation code and the MNI digital brain phantom. The phantom is a three-dimensional data-set that defines the spatial distribution of different tissues. Time activity curves were calculated using an impulse response function specified by generally accepted rate constants, convolved with an input function obtained by blood sampling, and assigned to grey and white matter tissue regions. We created a dynamic PET study using PET-SORTEO configured to simulate an ECAT Exact HR+. The resulting sinograms were reconstructed with all corrections, using variations of FBP and OSEM. Having constructed the dynamic PET data-sets, we used them to evaluate the performance of intensity-based registration as part of a tool for quantifying hyper/hypo perfusion with particular application to analysis of brain dementia scans, and a study of the stability of kinetic parameter estimation.

  19. FDG-PET imaging in mild traumatic brain injury: a critical review.

    PubMed

    Byrnes, Kimberly R; Wilson, Colin M; Brabazon, Fiona; von Leden, Ramona; Jurgens, Jennifer S; Oakes, Terrence R; Selwyn, Reed G

    2014-01-09

    Traumatic brain injury (TBI) affects an estimated 1.7 million people in the United States and is a contributing factor to one third of all injury related deaths annually. According to the CDC, approximately 75% of all reported TBIs are concussions or considered mild in form, although the number of unreported mild TBIs (mTBI) and patients not seeking medical attention is unknown. Currently, classification of mTBI or concussion is a clinical assessment since diagnostic imaging is typically inconclusive due to subtle, obscure, or absent changes in anatomical or physiological parameters measured using standard magnetic resonance (MR) or computed tomography (CT) imaging protocols. Molecular imaging techniques that examine functional processes within the brain, such as measurement of glucose uptake and metabolism using [(18)F]fluorodeoxyglucose and positron emission tomography (FDG-PET), have the ability to detect changes after mTBI. Recent technological improvements in the resolution of PET systems, the integration of PET with magnetic resonance imaging (MRI), and the availability of normal healthy human databases and commercial image analysis software contribute to the growing use of molecular imaging in basic science research and advances in clinical imaging. This review will discuss the technological considerations and limitations of FDG-PET, including differentiation between glucose uptake and glucose metabolism and the significance of these measurements. In addition, the current state of FDG-PET imaging in assessing mTBI in clinical and preclinical research will be considered. Finally, this review will provide insight into potential critical data elements and recommended standardization to improve the application of FDG-PET to mTBI research and clinical practice.

  20. PET study of 11C-acetoacetate kinetics in rat brain during dietary treatments affecting ketosis.

    PubMed

    Bentourkia, M'hamed; Tremblay, Sébastien; Pifferi, Fabien; Rousseau, Jacques; Lecomte, Roger; Cunnane, Stephen

    2009-04-01

    Normally, the brain's fuel is glucose, but during fasting it increasingly relies on ketones (beta-hydroxybutyrate, acetoacetate, and acetone) produced in liver mitochondria from fatty acid beta-oxidation. Although moderately raised blood ketones produced on a very high fat ketogenic diet have important clinical effects on the brain, including reducing seizures, ketone metabolism by the brain is still poorly understood. The aim of the present work was to assess brain uptake of carbon-11-labeled acetoacetate (11C-acetoacetate) by positron emission tomography (PET) imaging in the intact, living rat. To vary plasma ketones, we used three dietary conditions: high carbohydrate control diet (low plasma ketones), fat-rich ketogenic diet (raised plasma ketones), and 48-h fasting (raised plasma ketones). 11C-acetoacetate metabolism was measured in the brain, heart, and tissue in the mouth area. Using 11C-acetoacetate and small animal PET imaging, we have noninvasively quantified an approximately seven- to eightfold enhanced brain uptake of ketones on a ketogenic diet or during fasting. This opens up an opportunity to study brain ketone metabolism in humans.

  1. PET studies in epilepsy.

    PubMed

    Sarikaya, Ismet

    2015-01-01

    sclerosis complex. (15)O-H2O PET was reported to have a similar sensitivity to FDG-PET in detecting epileptic foci.

  2. PET studies in epilepsy

    PubMed Central

    Sarikaya, Ismet

    2015-01-01

    . 15O-H2O PET was reported to have a similar sensitivity to FDG-PET in detecting epileptic foci. PMID:26550535

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

    PubMed

    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.

  4. Iodine-122-labeled amphetamine derivative with potential for PET brain blood-flow studies

    SciTech Connect

    Mathis, C.A.; Sargent, T. 3d.; Shulgin, A.T.

    1985-11-01

    The positron emitter SSI (t1/2 3.6 min) was collected from a xenon- SS/iodine- SS ( SSXe/ SSI) generator and incorporated into an amphetamine analog, 2,4-dimethoxy-N,N-dimethyl-5-( SSI)iodophenylisopropylamine (5-( SSI)-2,4-DNNA). The remote synthesis was achieved in 3 min with a 50% radioincorporation yield and a product radiopurity of greater than 98%. 5-( SSI)-2,4-DNNA was injected into a beagle dog and a brain section imaged with positron emission tomography (PET). The uptake and retention of 5-( SSI)-2,4-DNNA was compared to that of YSRb in the same animal. Dynamic PET activity data were obtained 0-20 min postinjection of 5-( SSI)-2,4-DNNA and showed rapid uptake by brain and good cerebral/extracerebral tissue distinction. A whole-body scan of a dog was also obtained with 5-123I-2,4-DNNA showing uptake in brain, lung, and other body organs. The feasibility of incorporating SSI into an extracted brain perfusion agent for use with PET is demonstrated.

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

    PubMed Central

    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

    2015-01-01

    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. PMID:25848027

  6. Evoked Potentials and Neuropsychological Tests Validate Positron Emission Topography (PET) Brain Metabolism in Cognitively Impaired Patients

    PubMed Central

    Braverman, Eric R.; Blum, Kenneth; Damle, Uma J.; Kerner, Mallory; Dushaj, Kristina; Oscar-Berman, Marlene

    2013-01-01

    Fluorodeoxyglucose (FDG) Positron Emission Topography (PET) brain hypometabolism (HM) correlates with diminished cognitive capacity and risk of developing dementia. However, because clinical utility of PET is limited by cost, we sought to determine whether a less costly electrophysiological measure, the P300 evoked potential, in combination with neuropsychological test performance, would validate PET HM in neuropsychiatric patients. We found that patients with amnestic and non-amnestic cognitive impairment and HM (n = 43) evidenced significantly reduced P300 amplitudes, delayed latencies, and neuropsychological deficits, compared to patients with normal brain metabolism (NM; n = 187). Data from patients with missing cognitive test scores (n = 57) were removed from the final sample, and logistic regression modeling was performed on the modified sample (n = 173, p = .000004). The logistic regression modeling, based on P300 and neuropsychological measures, was used to validate membership in the HM vs. NM groups. It showed classification validation in 13/25 HM subjects (52.0%) and in 125/148 NM subjects (84.5%), correlating with total classification accuracy of 79.8%. In this paper, abnormal P300 evoked potentials coupled with cognitive test impairment validates brain metabolism and mild/moderate cognitive impairment (MCI). To this end, we cautiously propose incorporating electrophysiological and neuropsychological assessments as cost-effective brain metabolism and MCI indicators in primary care. Final interpretation of these results must await required additional studies confirming these interesting results. PMID:23526928

  7. Integrated modeling of PET and DTI information based on conformal brain mapping

    NASA Astrophysics Data System (ADS)

    Zou, Guangyu; Xi, Yongjian; Heckenburg, Greg; Duan, Ye; Hua, Jing; Gu, Xiangfeng

    2006-03-01

    Recent advances in imaging technologies, such as Magnetic Resonance Imaging (MRI), Positron Emission Tomography (PET) and Diffusion Tensor Imaging (DTI) have accelerated brain research in many aspects. In order to better understand the synergy of the many processes involved in normal brain function, integrated modeling and analysis of MRI, PET, and DTI is highly desirable. Unfortunately, the current state-of-art computational tools fall short in offering a comprehensive computational framework that is accurate and mathematically rigorous. In this paper we present a framework which is based on conformal parameterization of a brain from high-resolution structural MRI data to a canonical spherical domain. This model allows natural integration of information from co-registered PET as well as DTI data and lays the foundation for a quantitative analysis of the relationship between diverse data sets. Consequently, the system can be designed to provide a software environment able to facilitate statistical detection of abnormal functional brain patterns in patients with a large number of neurological disorders.

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

    PubMed

    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.

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

    PubMed

    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.

  10. PET imaging of neurogenic activity in the adult brain: Toward in vivo imaging of human neurogenesis.

    PubMed

    Tamura, Yasuhisa; Kataoka, Yosky

    2017-01-01

    Neural stem cells are present in 2 neurogenic regions, the subventricular zone (SVZ) and the subgranular zone (SGZ) of the hippocampal dentate gyrus (DG), and continue to generate new neurons throughout life. Adult hippocampal neurogenesis is linked to a variety of psychiatric disorders such as depression and anxiety, and to the therapeutic effects of antidepressants, as well as learning and memory. In vivo imaging for hippocampal neurogenic activity may be used to diagnose psychiatric disorders and evaluate the therapeutic efficacy of antidepressants. However, these imaging techniques remain to be established until now. Recently, we established a quantitative positron emission tomography (PET) imaging technique for neurogenic activity in the adult brain with 3'-deoxy-3'-[(18)F]fluoro-L-thymidine ([(18)F]FLT) and probenecid, a drug transporter inhibitor in blood-brain barrier. Moreover, we showed that this PET imaging technique can monitor alterations in neurogenic activity in the hippocampus of adult rats with depression and following treatment with an antidepressant. This PET imaging method may assist in diagnosing depression and in monitoring the therapeutic efficacy of antidepressants. In this commentary, we discuss the possibility of in vivo PET imaging for neurogenic activity in adult non-human primates and humans.

  11. A Factor-Image Framework to Quantification of Brain Receptor Dynamic PET Studies

    PubMed Central

    Wang, Z. Jane; Szabo, Zsolt; Lei, Peng; Varga, József; Liu, K. J. Ray

    2007-01-01

    The positron emission tomography (PET) imaging technique enables the measurement of receptor distribution or neurotransmitter release in the living brain and the changes of the distribution with time and thus allows quantification of binding sites as well as the affinity of a radioligand. However, quantification of receptor binding studies obtained with PET is complicated by tissue heterogeneity in the sampling image elements (i.e., voxels, pixels). This effect is caused by a limited spatial resolution of the PET scanner. Spatial heterogeneity is often essential in understanding the underlying receptor binding process. Tracer kinetic modeling also often requires an intrusive collection of arterial blood samples. In this paper, we propose a likelihood-based framework in the voxel domain for quantitative imaging with or without the blood sampling of the input function. Radioligand kinetic parameters are estimated together with the input function. The parameters are initialized by a subspace-based algorithm and further refined by an iterative likelihood-based estimation procedure. The performance of the proposed scheme is examined by simulations. The results show that the proposed scheme provides reliable estimation of factor time-activity curves (TACs) and the underlying parametric images. A good match is noted between the result of the proposed approach and that of the Logan plot. Real brain PET data are also examined, and good performance is observed in determining the TACs and the underlying factor images. PMID:18769527

  12. Pharmacologic perturbation as a potential tool to increase the sensitivity of FDG-PET in the evaluation of brain tumors

    SciTech Connect

    Wong, F.C.L.; Kim, E.E.; Yung, W.K.A.

    1994-05-01

    The usefulness of F-18 FDG PET in the study of brain tumors is limited by the high baseline cortical uptake which decreases the contrast of the tumor. Two alternatives to increase the tumor/background contrast have been reported: barbiturate-induced coma and postprandial state. This project evaluates the effects of sedation with diazepam or of oral glucose intake on the brain tumor/background contrast during F-18 FDG PET studies.

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

    NASA Astrophysics Data System (ADS)

    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

  14. Dual-modality brain PET-CT image segmentation based on adaptive use of functional and anatomical information.

    PubMed

    Xia, Yong; Eberl, Stefan; Wen, Lingfeng; Fulham, Michael; Feng, David Dagan

    2012-01-01

    Dual medical imaging modalities, such as PET-CT, are now a routine component of clinical practice. Medical image segmentation methods, however, have generally only been applied to single modality images. In this paper, we propose the dual-modality image segmentation model to segment brain PET-CT images into gray matter, white matter and cerebrospinal fluid. This model converts PET-CT image segmentation into an optimization process controlled simultaneously by PET and CT voxel values and spatial constraints. It is innovative in the creation and application of the modality discriminatory power (MDP) coefficient as a weighting scheme to adaptively combine the functional (PET) and anatomical (CT) information on a voxel-by-voxel basis. Our approach relies upon allowing the modality with higher discriminatory power to play a more important role in the segmentation process. We compared the proposed approach to three other image segmentation strategies, including PET-only based segmentation, combination of the results of independent PET image segmentation and CT image segmentation, and simultaneous segmentation of joint PET and CT images without an adaptive weighting scheme. Our results in 21 clinical studies showed that our approach provides the most accurate and reliable segmentation for brain PET-CT images.

  15. Effects of magnetic fields of up to 9.4 T on resolution and contrast of PET images as measured with an MR-BrainPET.

    PubMed

    Shah, N Jon; Herzog, Hans; Weirich, Christoph; Tellmann, Lutz; Kaffanke, Joachim; Caldeira, Liliana; Kops, Elena Rota; Qaim, Syed M; Coenen, Heinz H; Iida, Hidehiro

    2014-01-01

    Simultaneous, hybrid MR-PET is expected to improve PET image resolution in the plane perpendicular to the static magnetic field of the scanner. Previous papers have reported this either by simulation or experiment with simple sources and detector arrangements. Here, we extend those studies using a realistic brain phantom in a recently installed MR-PET system comprising a 9.4 T MRI-scanner and an APD-based BrainPET insert in the magnet bore. Point and line sources and a 3D brain phantom were filled with 18F (low-energy positron emitter), 68Ga (medium energy positron emitter) or 120I, a non-standard positron emitter (high positron energies of up to 4.6 MeV). Using the BrainPET insert, emission scans of the phantoms were recorded at different positions inside and outside the magnet bore such that the magnetic field was 0 T, 3 T, 7 T or 9.4 T. Brain phantom images, with the 'grey matter' compartment filled with 18F, showed no obvious resolution improvement with increasing field. This is confirmed by practically unchanged transaxial FWHM and 'grey/white matter' ratio values between at 0T and 9.4T. Field-dependent improvements in the resolution and contrast of transaxial PET images were clearly evident when the brain phantom was filled with 68Ga or 120I. The grey/white matter ratio increased by 7.3% and 16.3%, respectively. The greater reduction of the FWTM compared to FWHM in 68Ga or 120I line-spread images was in agreement with the improved contrast of 68Ga or 120I images. Notwithstanding elongations seen in the z-direction of 68Ga or 120I point source images acquired in foam, brain phantom images show no comparable extension. Our experimental study confirms that integrated MR-PET delivers improved PET image resolution and contrast for medium- and high-energy positron emitters even though the positron range is reduced only in directions perpendicular to the magnetic field.

  16. Effects of Magnetic Fields of up to 9.4 T on Resolution and Contrast of PET Images as Measured with an MR-BrainPET

    PubMed Central

    Shah, N. Jon; Herzog, Hans; Weirich, Christoph; Tellmann, Lutz; Kaffanke, Joachim; Caldeira, Liliana; Kops, Elena Rota; Qaim, Syed M.; Coenen, Heinz H.; Iida, Hidehiro

    2014-01-01

    Simultaneous, hybrid MR-PET is expected to improve PET image resolution in the plane perpendicular to the static magnetic field of the scanner. Previous papers have reported this either by simulation or experiment with simple sources and detector arrangements. Here, we extend those studies using a realistic brain phantom in a recently installed MR-PET system comprising a 9.4 T MRI-scanner and an APD-based BrainPET insert in the magnet bore. Point and line sources and a 3D brain phantom were filled with 18F (low-energy positron emitter), 68Ga (medium energy positron emitter) or 120I, a non-standard positron emitter (high positron energies of up to 4.6 MeV). Using the BrainPET insert, emission scans of the phantoms were recorded at different positions inside and outside the magnet bore such that the magnetic field was 0 T, 3 T, 7 T or 9.4 T. Brain phantom images, with the ‘grey matter’ compartment filled with 18F, showed no obvious resolution improvement with increasing field. This is confirmed by practically unchanged transaxial FWHM and ‘grey/white matter’ ratio values between at 0T and 9.4T. Field-dependent improvements in the resolution and contrast of transaxial PET images were clearly evident when the brain phantom was filled with 68Ga or 120I. The grey/white matter ratio increased by 7.3% and 16.3%, respectively. The greater reduction of the FWTM compared to FWHM in 68Ga or 120I line-spread images was in agreement with the improved contrast of 68Ga or 120I images. Notwithstanding elongations seen in the z-direction of 68Ga or 120I point source images acquired in foam, brain phantom images show no comparable extension. Our experimental study confirms that integrated MR-PET delivers improved PET image resolution and contrast for medium- and high-energy positron emitters even though the positron range is reduced only in directions perpendicular to the magnetic field. PMID:24755872

  17. Guidelines to PET measurements of the target occupancy in the brain for drug development.

    PubMed

    Takano, Akihiro; Varrone, Andrea; Gulyás, Balázs; Salvadori, Piero; Gee, Antony; Windhorst, Albert; Vercouillie, Johnny; Bormans, Guy; Lammertsma, Adriaan A; Halldin, Christer

    2016-11-01

    This guideline summarizes the current view of the European Association of Nuclear Medicine Drug Development Committee. The purpose of this guideline is to guarantee a high standard of PET studies that are aimed at measuring target occupancy in the brain within the framework of development programs of drugs that act within the central nervous system (CNS drugs). This guideline is intended to present information specifically adapted to European practice. The information provided should be applied within the context of local conditions and regulations.

  18. Brain metabolic correlates of fatigue in Parkinson's disease: A PET study.

    PubMed

    Zhang, Li; Li, Tiannv; Yuan, Yongsheng; Tong, Qing; Jiang, Siming; Wang, Min; Wang, Jianwei; Ding, Jian; Xu, Qinrong; Zhang, Kezhong

    2017-09-18

    The neural bases of fatigue in Parkinson's disease (PD) remain uncertain. We aimed to assess the brain metabolic correlates of fatigue in patients with PD. Twenty-seven PD patients without clinically relevant depression (17-item Hamilton Depression Rating Scale [HAMD] score ≥ 14), apathy (Apathy Scale [AS] score ≥ 14) and excessive daytime somnolence (Epworth Sleepiness Scale [ESS] score ≥ 10) were evaluated with Fatigue Severity Scale (FSS). Each patient had an F-18 fluorodeoxyglucose PET (FDG-PET) scan. Motor symptoms were measured with the Unified Parkinson's Disease Rating Scale (UPDRS) motor part. Levodopa equivalent daily dose (LEDD) for each patient was also calculated. The PET images were analyzed using statistical parametric mapping software. We introduced the age, educational level, HAMD scores, AS scores and ESS scores as covariates. High FSS scores were associated with brain hypermetabolism in areas including the right middle temporal gyrus (Brodmann area [BA] 37) and left middle occipital gyrus (BA 19). Increased FSS scores correlated with hypometabolism in regions such as the right precuneus (BA 23), left inferior frontal gyrus (BA 45) and left superior frontal gyrus (orbital part, BA 11). This study demonstrates that brain areas including frontal, temporal and parietal regions indicative of emotion, motivation and cognitive functions are involved in fatigue in PD patients.

  19. (18)F-FET PET Uptake Characteristics in Patients with Newly Diagnosed and Untreated Brain Metastasis.

    PubMed

    Unterrainer, Marcus; Galldiks, Norbert; Suchorska, Bogdana; Kowalew, Lara-Caroline; Wenter, Vera; Schmid-Tannwald, Christine; Niyazi, Maximilian; Bartenstein, Peter; Langen, Karl-Josef; Albert, Nathalie L

    2017-04-01

    In patients with brain metastasis, PET using labeled amino acids has gained clinical importance, mainly regarding the differentiation of viable tumor tissue from treatment-related effects. However, there is still limited knowledge concerning the uptake characteristics in patients with newly diagnosed and untreated brain metastases. Hence, we evaluated the uptake characteristics in these patients using dynamic O-(2-(18)F-fluoroethyl)-l-tyrosine ((18)F-FET) PET. Methods: Patients with newly diagnosed brain metastases without prior local therapy and (18)F-FET PET scanning were retrospectively identified in 2 centers. Static and dynamic PET parameters (maximal/mean tumor-to-brain-ratio [TBRmax/TBRmean], biologic tumor volume [BTV], and time-activity curves with minimal time to peak [TTPmin]) were evaluated and correlated with MRI parameters (maximal lesion diameter, volume of contrast enhancement) and originating primary tumor. Results: Forty-five brain metastases in 30 patients were included. Forty of 45 metastases (89%) had a TBRmax ≥ 1.6 and were classified as (18)F-FET-positive (median TBRmax, 2.53 [range, 1.64-9.47]; TBRmean, 1.86 [range, 1.63-5.48]; and BTV, 3.59 mL [range, 0.04-23.98 mL], respectively). In 39 of 45 brain metastases eligible for dynamic analysis, a wide range of TTPmin was observed (median, 22.5 min; range, 4.5-47.5 min). All (18)F-FET-negative metastases had a diameter of ≤ 1.0 cm, whereas metastases with a > 1.0 cm diameter all showed pathologic (18)F-FET uptake, which did not correlate with lesion size. The highest variability of uptake intensity was observed within the group of melanoma metastases. Conclusion: Untreated metastases predominantly show increased (18)F-FET uptake, and only a third of metastases < 1.0 cm were (18)F-FET-negative, most likely because of scanner resolution and partial-volume effects. In metastases > 1.0 cm, (18)F-FET uptake intensity was highly variable and independent of tumor size (even intraindividually). (18

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

    NASA Astrophysics Data System (ADS)

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

    2010-04-01

    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 57Co transmission point source with a 4% energy window. The optimal energy window for a 68Ge transmission source operating in singles acquisition mode was 20%, independent of the source strength, providing bias-noise performance almost as good as for 57Co. 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 [18F]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 57Co (4% energy window) or 68Ge (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.

  1. PET imaging of brain inflammation during early epileptogenesis in a rat model of temporal lobe epilepsy

    PubMed Central

    2012-01-01

    Background Recently, inflammatory cascades have been suggested as a target for epilepsy therapy. Positron emission tomography (PET) imaging offers the unique possibility to evaluate brain inflammation longitudinally in a non-invasive translational manner. This study investigated brain inflammation during early epileptogenesis in the post-kainic acid-induced status epilepticus (KASE) model with post-mortem histology and in vivo with [18F]-PBR111 PET. Methods Status epilepticus (SE) was induced (N = 13) by low-dose injections of KA, while controls (N = 9) received saline. Translocator protein (TSPO) expression and microglia activation were assessed with [125I]-CLINDE autoradiography and OX-42 immunohistochemistry, respectively, 7 days post-SE. In a subgroup of rats, [18F]-PBR111 PET imaging with metabolite-corrected input function was performed before post-mortem evaluation. [18F]-PBR111 volume of distribution (Vt) in volume of interests (VOIs) was quantified by means of kinetic modelling and a VOI/metabolite-corrected plasma activity ratio. Results Animals with substantial SE showed huge overexpression of TSPO in vitro in relevant brain regions such as the hippocampus and amygdala (P < 0.001), while animals with mild symptoms displayed a smaller increase in TSPO in amygdala only (P < 0.001). TSPO expression was associated with OX-42 signal but without obvious cell loss. Similar in vivo [18F]-PBR111 increases in Vt and the simplified ratio were found in key regions such as the hippocampus (P < 0.05) and amygdala (P < 0.01). Conclusion Both post-mortem and in vivo methods substantiate that the brain regions important in seizure generation display significant brain inflammation during epileptogenesis in the KASE model. This work enables future longitudinal investigation of the role of brain inflammation during epileptogenesis and evaluation of anti-inflammatory treatments. PMID:23136853

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

    PubMed

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

    2016-11-01

    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 to

  3. Investigation of partial volume correction methods for brain FDG PET studies

    NASA Astrophysics Data System (ADS)

    Yang, J.; Huang, S. C.; Mega, M.; Lin, K. P.; Toga, A. W.; Small, G. W.; Phelps, M. E.

    1996-12-01

    The use of positron emission tomography (PET) in quantitative fluorodeoxyglucose (FDG) studies of aging and dementia has been limited by partial volume effects. A general method for correction of partial volume effects (PVE) in PET involves the following common procedures: segmentation of MRI brain images into gray matter (GM), white matter (WM), cerebral spinal fluid (CSF), and muscle (MS) components: MRI PET registration; and generation of simulated PET images. Afterward, two different approaches can be taken. The first approach derives first a pixel-by-pixel correction map as the ratio of the measured image to the simulated image [with realistic full-width at half-maximum (FWHM)]. The correction map was applied to the MRI segmentation image. Regions of interest (ROI's) can then be applied to give results free of partial volume effects. The second approach uses the ROI values of the simulated "pure" image (with negligible FWHM) and those of the simulated and the measured PET images to correct for the PVE effect. By varying the ratio of radiotracer concentrations for different tissue components, the in-plane FWHM's of a three-dimensional point spread function, and the ROI size, the authors evaluated the performance of these two approaches in terms of their accuracy and sensitivity to different simulation configurations. The results showed that both approaches are more robust than the approach developed by Muller-Gartner et al. (1992), and the second approach is more accurate and more robust than the first. In conclusion, the authors recommend that the second approach should be used on FDG PET images to correct for partial volume effects and to determine whether an apparent change in GM radiotracer concentration is truly due to metabolic changes.

  4. Investigation of partial volume correction methods for brain FDG PET studies

    SciTech Connect

    Yang, J.; Huang, S.C.; Mega, M.; Toga, A.W.; Small, G.W.; Phelps, M.E.; Lin, K.P.

    1996-12-01

    The use of positron emission tomography (PET) in quantitative fluorodeoxyglucose (FDG) studies of aging and dementia has been limited by partial volume effects. A general method for correction of partial volume effects (PVE) in PET involves the following common procedures; segmentation of MRI brain images into gray matter (GM), white matter (WM), cerebral spinal fluid (CSF), and muscle (MS) components; MRI PET registration; and generation of simulated PET images. Afterward, two different approaches can be taken. The first approach derives first a pixel-by-pixel correction map as the ratio of the measured image to the simulated image [with realistic full-width at half-maximum (FWHM)]. The correction map was applied to the MRI segmentation image. Regions of interest (ROI`s) can then be applied to give results free of partial volume effects. The second approach uses the ROI values of the simulated ``pure`` image (with negligible FWHM) and those of the simulated and the measured PET images to correct for the PVE effect. By varying the ratio of radiotracer concentrations for different tissue components, the in-plane FWHM`s of a three-dimensional point spread function, and the ROI size, the authors evaluated the performance of these two approaches in terms of their accuracy and sensitivity to different simulation configurations. The results showed that both approaches are more robust than the approach developed by Muller-Gartner et al., and the second approach is more accurate and more robust than the first. In conclusion, the authors recommend that the second approach should be used on FDG PET images to correct for partial volume effects and to determine whether an apparent change in GM radiotracer concentration is truly due to metabolic changes.

  5. Common malignant brain tumors: can 18F-FDG PET/CT aid in differentiation?

    PubMed

    Purandare, Nilendu C; Puranik, Ameya; Shah, Sneha; Agrawal, Archi; Gupta, Tejpal; Moiyadi, Aliasgar; Shetty, Prakash; Shridhar, Epari; Jalali, Rakesh; Rangarajan, Venkatesh

    2017-09-15

    The objectives of this study were to evalute the metabolic characteristics of common malignant space-occupying lesions (SOL) of the brain and to determine the utility of fluorine-18-fluorodeoxyglucose (F-FDG) PET/CT in differentiating between the common types of malignant brain SOL. All patients with brain SOL who were referred for an F-FDG PET/CT scan by a multidisciplinary team were included in this retrospective study. The metabolic characteristics of the brain lesions in the form of maximum standardized uptake value (SUVmax) along with tumor-to-background activity ratios were determined and differences were compared using nonparametric statistical tests. Histopathological confirmation was used as the gold standard in all patients. Receiver operating characteristic curve analysis was used to find the optimal SUVmax cutoff to differentiate the tumor types. Glioblastoma multiforme (GBM; n=30), lymphoma (n=25), and metastases (n=46) accounted for most malignant tumors (95.2%). Lymphomas showed a significantly high metabolic uptake (median SUVmax=20.3, range: 8.1-46.3) compared with GBM ( median SUVmax=10.3, range: 2.6-21.7) and metastases (median SUVmax=11.5, range: 2.9-19.6) (P=0.00). The tumor-to-background activity ratios for lymphomas were also significantly higher. There was an overlap in the metabolic uptake of GBM and metastases, with no significant difference between their SUVmax values (P=0.245). A SUVmax more than 15.5 showed an 84% sensitivity and an 80% specificity to diagnose lymphomas (area under the curve=0.876, P=0.00). Four patients with brain lymphoma had extracranial disease on F-FDG PET. Lung cancer was the most common primary malignancy in patients with brain metastases. Central nervous system lymphomas can be differentiated from GBM and metastases by their higher metabolic activity. In addition, F-FDG PET/CT can potentially impact therapeutic decisions by detecting primary malignancy in patients with metastatic brain lesions and extracranial

  6. Positron emission tomographic measurement of cerebral blood flow and permeability-surface area product of water using (/sup 15/O)water and (/sup 11/C)butanol

    SciTech Connect

    Herscovitch, P.; Raichle, M.E.; Kilbourn, M.R.; Welch, M.J.

    1987-10-01

    We have previously adapted Kety's tissue autoradiographic method for measuring regional CBF in laboratory animals to the measurement of CBF in humans with positron emission tomography (PET) and H/sub 2/(/sup 15/)O. Because this model assumes diffusion equilibrium between tissue and venous blood, the use of a diffusion-limited tracer, such as H/sub 2/(/sup 15/)O, may lead to an underestimation of CBF. We therefore validated the use of (/sup 11/C)butanol as an alternative freely diffusible tracer for PET. We then used it in humans to determine the underestimation of CBF that occurs with H/sub 2/(/sup 15/)O, and thereby were able to calculate the extraction Ew and permeability-surface area product PSw of H/sub 2/(/sup 15/)O. Measurements of the permeability of rhesus monkey brain to (/sup 11/C)butanol, obtained by means of an intracarotid injection, external detection technique, demonstrated that this tracer is freely diffusible up to a CBF of at least 170 ml/min-100 g. CBF measured in baboons with the PET autoradiographic method and (/sup 11/C)butanol was then compared with CBF measured in the same animals with a standard residue detection method. An excellent correspondence was obtained between both of these measurements. Finally, paired PET measurements of CBF were made with both H/sub 2/(/sup 15/)O and (/sup 11/C)butanol in 17 normal human subjects. Average global CBF was significantly greater when measured with (/sup 11/C)butanol (53.1 ml/min-100 g) than with H/sub 2/(/sup 15/)O (44.4 ml/min-100 g). Average global Ew was 0.84 and global PSw was 104 ml/min-100 g. Regional measurements showed a linear relationship between local PSw and CBF, while Ew was relatively uniform throughout the brain. Simulations were used to determine the potential error associated with the use of an incorrect value for the brain-blood partition coefficient for (/sup 11/C)butanol and to calculate the effect of tissue heterogeneity and errors in flow measurement on the calculation of PSw.

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

    PubMed

    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., 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

  8. Concurrent Low Brain and High Liver Uptake on FDG PET Are Associated with Cardiovascular Risk Factors

    PubMed Central

    Nam, Hyun-Yeol; Jun, Sungmin; Pak, Kyoungjune

    2017-01-01

    Objective Concurrent low brain and high liver uptake are sometimes observed on fluorine-18-labeled fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET). We investigated the potential clinical significance of this uptake pattern related to metabolic syndrome (MS). Materials and Methods We retrospectively reviewed data from 264 consecutive males who had undergone general health check-ups, including FDG PET/CT scans. After an overnight fast, the men had their peripheral blood drawn and the levels of various laboratory parameters measured; an FDG PET/CT scan was performed on the same day. We measured the maximum standardized uptake values of the brain and liver from regions of interest manually placed over the frontal cortex at the level of the centrum semiovale and the right lobe of the liver parenchyma, respectively. Results Fasting blood glucose (FBG; odds ratio [OR] = 1.063, p < 0.001) and glycated hemoglobin (HbA1c; OR = 3.634, p = 0.010) were the strongest predictive factors for low brain FDG uptake, whereas waist circumference (OR = 1.200, p < 0.001) and γ-glutamyl transpeptidase (OR = 1.012, p = 0.001) were the strongest predictive factors for high liver uptake. Eleven subjects (4.2%) showed concurrent low brain and high liver FDG uptake, and all but one of these subjects (90.9%) had MS. Systolic blood pressure, waist circumference, FBG, triglyceride, alanine aminotransferase, insulin resistance (measured by homeostasis model assessment), insulin, HbA1c, and body mass index were higher in subjects with this FDG uptake pattern than in those without (all, p < 0.001). Conclusion Concurrent low brain and high liver FDG uptake were closely associated with MS. Moreover, subjects with this pattern had higher values for various cardiovascular risk factors than did those without. PMID:28246520

  9. Although Non-diagnostic Between Necrosis and Recurrence, FDG PET/CT Assists Management of Brain Tumours After Radiosurgery.

    PubMed

    Torrens, Michael; Malamitsi, Julia; Karaiskos, Pantelis; Valotassiou, Varvara; Laspas, Fotis; Andreou, John; Stergiou, Christos; Prassopoulos, Vassilis

    2016-01-01

    To re-evaluate the role of (18)F-fluoro-deoxy-D-glucose (FDG) positron emission tomography/ computer assisted tomography (PET/CT) co-registered with magnetic resonance imaging (MRI) in differentiating adverse radiation effect (ARE) from tumour recurrence after Gamma Knife radiosurgery of brain tumours. Twenty-seven PET/CT studies co-registered with MRI were performed on 16 patients after radiosurgery, with 12/16 patients having multiple radiosurgery treatments. Long term follow-up was used for evaluation, with 3/16 patients being histopathologically confirmed. PET/CT was positive in all studies in 6/16 patients, negative in all studies in 6/16 and changed from negative to positive in one. In 2/16 patients, PET/CT was both positive and negative in separate tumour foci. In 9/16 cases with a positive PET/CT, tumour was confirmed. In 6/16 patients with a negative PET/CT, 3/6 had recurrence and 3/6 ARE. In 1/16, equivocal results became negative after retreatment. PET/CT/MRI identified tumour within ARE. Sensitivity of PET/CT/MRI proved to be 64.7%, and specificity 100%. PET/CT/MRI assists management, by revealing metabolism rather than histology. Copyright © 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  10. Positron Emission Tomography (PET) Quantification of GABAA Receptors in the Brain of Fragile X Patients.

    PubMed

    D'Hulst, Charlotte; Heulens, Inge; Van der Aa, Nathalie; Goffin, Karolien; Koole, Michel; Porke, Kathleen; Van De Velde, Marc; Rooms, Liesbeth; Van Paesschen, Wim; Van Esch, Hilde; Van Laere, Koen; Kooy, R Frank

    2015-01-01

    Over the last several years, evidence has accumulated that the GABAA receptor is compromised in animal models for fragile X syndrome (FXS), a common hereditary form of intellectual disability. In mouse and fly models, agonists of the GABAA receptor were able to rescue specific consequences of the fragile X mutation. Here, we imaged and quantified GABAA receptors in vivo in brain of fragile X patients using Positron Emission Topography (PET) and [11C]flumazenil, a known high-affinity and specific ligand for the benzodiazepine site of GABAA receptors. We measured regional GABAA receptor availability in 10 fragile X patients and 10 control subjects. We found a significant reduction of on average 10% in GABAA receptor binding potential throughout the brain in fragile X patients. In the thalamus, the brain region showing the largest difference, the GABAA receptor availability was even reduced with 17%. This is one of the first reports of a PET study of human fragile X brain and directly demonstrates that the GABAA receptor availability is reduced in fragile X patients. The study reinforces previous hypotheses that the GABAA receptor is a potential target for rational pharmacological treatment of fragile X syndrome.

  11. Brain FDG-PET metabolic abnormalities in Macrophagic Myofasciitis: Are They Stable?

    PubMed

    Blanc-Durand, Paul; Van Der Gucht, Axel; Aoun Sebaiti, Mehdi; Abulizi, Mukedaisi; Authier, Francois-Jérome; Itti, Emmanuel

    2017-03-16

    We address this letter in addition to our recent published study (1). The aim is to add some insight to the evolution of the brain abnormalities that are observed with macrophagic myofasciitis (MMF). MMF is a chronic disease whom evolution is slow and symptoms first may occurs from months to year after a vaccination containing aluminium hydroxid adjuvants (2). Nevertheless, its evolution is not fully understood or known. MMF associated cognitive dysfunction (MACD) is based on a tripod combining dysexecutive syndrom, visual memory impairment and interhemispheric disconnection. One pilot study suggest that MACD appears clinically stable over time (3). One recent study evaluating a support vector machine classifier also suggest that the abnormalities observed with 18-fluorodeoxyglose positron emission tomography ((18)F-FDG PET) may be sensitive and could be used to monitor patients. The study population comes from cohort followed in our Reference Center for Rare Neuromuscular Diseases and data were collected retrospectively. Among those patients, 15 had two consecutives (18)F-FDG PET brain acquisitions (median age 42.1 [range 20.9 to 63.5]) following the same brain protocol acquisition as previously described (1). Median time duration between the two examinations was 2.3 years (range 0.5 to 4]. Using analysis of covariance and negative or positive contrast in SPM12, a t-test mask was generated from the comparison between the two means of the first cerebral (18)F-FDG PET images and between the mean of the second acquisition. Results of the comparison were collected at a P-value < 0.005 at the voxel level, for clusters k ≥ 200 voxels (corrected for cluster volume) with adjustment for age. Brain abnormalities maps didn't show any statistical difference between the two examinations confirming the idea that MMF is a slowly or not progressive disease and it is in concordance with the fact that neurological symptoms even if fluctuate do not worsen over time (nor ameliorate).

  12. MR-guided joint reconstruction of activity and attenuation in brain PET-MR.

    PubMed

    Mehranian, Abolfazl; Zaidi, Habib; Reader, Andrew J

    2017-09-13

    structural boundaries and at the same time improving the quantitative accuracy of the PET images. Our clinical reconstruction results showed that the MLEM-MRAC, P-MLEM-MRAC, MLAA, P-MLAA(+) and P-MLAA(++) algorithms result in, on average, quantification errors of -13.5 ± 3.1%, -13.4 ± 3.1%, -2.0 ± 6.5%, -3.0 ± 3.5% and -4.2 ± 3.6%, respectively, in different regions of the brain. In conclusion, whilst the P-MLAA(+) algorithm showed the best overall quantification performance, the proposed P-MLAA(++) algorithm provided simultaneous partial volume and attenuation corrections with only a minor compromise of PET quantification. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

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

    PubMed

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

    2015-12-01

    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. 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. 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. 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 together with nonlinear registration algorithms

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

    SciTech Connect

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

    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

  15. FDG PET brain scan demonstrated glucose hypometabolism of bilateral caudate nuclei and putamina in a patient with chorea-acanthocytosis.

    PubMed

    Cui, Ruixue; You, Hui; Niu, Na; Li, Fang

    2015-12-01

    Chorea-acanthocytosis is 1 type of neuroacanthocytosis that is a group of rare, hereditary neurodegenerative disorders. We presented a brain FDG PET finding of a 31-year-old woman with chorea-acanthocytosis. The images demonstrated significant hypometabolism in bilateral caudate nuclei and putamina. The finding of FDG PET is more prominent than that of MRI. Another interesting observation is the mildly increased FDG uptake in pituitary gland, although its relationship with the disease is unclear.

  16. Short-Term Practice Effects and Brain Hypometabolism: Preliminary Data from an FDG PET Study

    PubMed Central

    Duff, Kevin; Horn, Kevin P.; Foster, Norman L.; Hoffman, John M.

    2015-01-01

    Practice effects are improvements in cognitive test scores due to repeated exposure to the same tests. Typically viewed as error, short-term practice effects have been shown to provide valuable clinical information about diagnosis, prognosis, and treatment outcomes in older patients with mild cognitive impairments. This study examined short-term practice effects across one week and brain hypometabolism on fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) in 25 older adults (15 intact, 10 Mild Cognitive Impairment). Averaged cerebral brain metabolism on FDG PET was correlated with multiple cognitive scores at baseline in those with Mild Cognitive Impairment, and short-term practice effects accounted for additional variance in these same subjects. The relationship between brain metabolism and cognition (either at baseline or practice effects) was minimal in the intact individuals. Although needing replication in larger samples, short-term practice effects on tests of executive functioning and memory may provide valuable information about biomarkers of Alzheimer’s disease. PMID:25908614

  17. Preserved pontine glucose metabolism in Alzheimer disease: A reference region for functional brain image (PET) analysis

    SciTech Connect

    Minoshima, Satoshi; Frey, K.A.; Foster, N.L.; Kuhl, D.W.

    1995-07-01

    Our goal was to examine regional preservation of energy metabolism in Alzheimer disease (AD) and to evaluate effects of PET data normalization to reference regions. Regional metabolic rates in the pons, thalamus, putamen, sensorimotor cortex, visual cortex, and cerebellum (reference regions) were determined stereotaxically and examined in 37 patients with probable AD and 22 normal controls based on quantitative {sup 18}FDG-PET measurements. Following normalization of metabolic rates of the parietotemporal association cortex and whole brain to each reference region, distinctions of the two groups were assessed. The pons showed the best preservation of glucose metabolism in AD. Other reference regions showed relatively preserved metabolism compared with the parietotemporal association cortex and whole brain, but had significant metabolic reduction. Data normalization to the pons not only enhanced statistical significance of metabolic reduction in the parietotemporal association cortex, but also preserved the presence of global cerebral metabolic reduction indicated in analysis of the quantitative data. Energy metabolism in the pons in probable AD is well preserved. The pons is a reliable reference for data normalization and will enhance diagnostic accuracy and efficiency of quantitative and nonquantitative functional brain imaging. 39 refs., 2 figs., 3 tabs.

  18. Striatofrontal Deafferentiation in MSA-P: Evaluation with [18F]FDG Brain PET

    PubMed Central

    Kim, Hae Won; Oh, Minyoung; Oh, Jungsu S.; Oh, Seung Jun; Lee, Sang Ju; Chung, Sun Ju; Kim, Jae Seung

    2017-01-01

    Background Although cognitive impairment is not a consistent feature of multiple system atrophy (MSA), increasing evidence suggests that cognitive impairment is common in MSA with predominant parkinsonism (MSA-P). It is assumed that the cognitive impairment in MSA-P is caused by the striatal dysfunction and disruption of striatofrontal connections. The aim of this study was to evaluate the relationship between regional glucose metabolism in the frontal cortex and striatum in patients with MSA-P using [18F]FDG brain PET. Methods Twenty-nine patients with MSA-P and 28 healthy controls underwent [18F]FDG brain PET scan. The [18F]FDG brain PET images were semiquantitatively analyzed on the basis of a template in standard space. The regional glucose metabolism of the cerebral cortex and striatum were compared between MSA-P and healthy control groups. The correlations between age, symptom duration, H&Y stage, UPDRS III score, MMSE score, and glucose metabolism in the cerebellum and striatum to glucose metabolism in the frontal cortex were evaluated by multivariate analysis. Results The glucose metabolism in the frontal cortex and striatum in MSA-P patients were significantly lower than those in healthy controls. Glucose metabolism in the striatum was the most powerful determinant of glucose metabolism in the frontal cortex in MSA-P. Only age and glucose metabolism in the cerebellum were independent variables affecting the glucose metabolism in the frontal cortex in healthy controls. Conclusion The decrease in frontal glucose metabolism in MSA-P is related to the decrease in striatal glucose metabolism. This result provided evidence of striatofrontal deafferentiation in patients with MSA-P. PMID:28085923

  19. Striatofrontal Deafferentiation in MSA-P: Evaluation with [18F]FDG Brain PET.

    PubMed

    Kim, Hae Won; Oh, Minyoung; Oh, Jungsu S; Oh, Seung Jun; Lee, Sang Ju; Chung, Sun Ju; Kim, Jae Seung

    2017-01-01

    Although cognitive impairment is not a consistent feature of multiple system atrophy (MSA), increasing evidence suggests that cognitive impairment is common in MSA with predominant parkinsonism (MSA-P). It is assumed that the cognitive impairment in MSA-P is caused by the striatal dysfunction and disruption of striatofrontal connections. The aim of this study was to evaluate the relationship between regional glucose metabolism in the frontal cortex and striatum in patients with MSA-P using [18F]FDG brain PET. Twenty-nine patients with MSA-P and 28 healthy controls underwent [18F]FDG brain PET scan. The [18F]FDG brain PET images were semiquantitatively analyzed on the basis of a template in standard space. The regional glucose metabolism of the cerebral cortex and striatum were compared between MSA-P and healthy control groups. The correlations between age, symptom duration, H&Y stage, UPDRS III score, MMSE score, and glucose metabolism in the cerebellum and striatum to glucose metabolism in the frontal cortex were evaluated by multivariate analysis. The glucose metabolism in the frontal cortex and striatum in MSA-P patients were significantly lower than those in healthy controls. Glucose metabolism in the striatum was the most powerful determinant of glucose metabolism in the frontal cortex in MSA-P. Only age and glucose metabolism in the cerebellum were independent variables affecting the glucose metabolism in the frontal cortex in healthy controls. The decrease in frontal glucose metabolism in MSA-P is related to the decrease in striatal glucose metabolism. This result provided evidence of striatofrontal deafferentiation in patients with MSA-P.

  20. [(11)C]MADAM, a new serotonin transporter radioligand characterized in the monkey brain by PET.

    PubMed

    Halldin, Christer; Lundberg, Johan; Sóvágó, Judit; Gulyás, Balázs; Guilloteau, Denis; Vercouillie, Johnny; Emond, Patrick; Chalon, Sylvie; Tarkiainen, Jari; Hiltunen, Jukka; Farde, Lars

    2005-12-01

    The aim of this study was to explore the potential of a new selective serotonin transporter (5-HTT) inhibitor, N,N-dimethyl-2-(2-amino-4-methylphenylthio)benzylamine (MADAM, K(i)=1.65 nM), as a PET radioligand for examination of 5-HTT in the nonhuman primate brain. MADAM was radiolabeled by an N-methylation reaction using [(11)C]methyl triflate and the binding was characterized by PET in four cynomolgus monkeys. Metabolite levels in plasma were measured by gradient high-performance liquid chromatography (HPLC). The radiochemical incorporation yield of [(11)C]MADAM was 75-80% and the specific radioactivity at the time of administration was 34-652 GBq/micromol (n=8). The highest uptake of radioactivity was observed in striatum, thalamus, mesencephalon, and the lower brainstem. Lower binding was detected in neocortex and the lowest radioactive uptake was found in the cerebellum. This distribution is in accordance with the known expression of 5-HTT in vitro. The fraction of the total radioactivity in monkey plasma representing unchanged [(11)C]MADAM was 20% at 45 min after injection, as measured by gradient HPLC. Pretreatment measurements, using unlabeled citalopram, GBR 12909, and maprotiline, as well as a displacement measurement, using unlabeled MADAM, confirmed that [(11)C]MADAM binds selectively and reversibly to 5-HTT, and support the use of the cerebellum as reference region. The present characterization of binding in the monkey brain suggests that [(11)C]MADAM is a potential PET radioligand for quantitative studies of 5-HTT binding in the human brain.

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

    PubMed

    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 < 0.001) involving the occipital lobes, temporal lobes, limbic system, cerebellum, and frontoparietal cortices, as shown by analysis of covariance. The subgroup of patients with FSC dysfunction exhibited a larger extent of involved areas (35,223 voxels vs. 13,680 voxels in the subgroup with Papez circuit dysfunction and 5,453 voxels in patients without cognitive impairment). Nonsignificant results were obtained for the last subgroup because of its small population size. Conclusion: Our study identified a peculiar spatial pattern of cerebral 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.

  2. Region specific optimization of continuous linear attenuation coefficients based on UTE (RESOLUTE): application to PET/MR brain imaging.

    PubMed

    Ladefoged, Claes N; Benoit, Didier; Law, Ian; Holm, Søren; Kjær, Andreas; Højgaard, Liselotte; Hansen, Adam E; Andersen, Flemming L

    2015-10-21

    The reconstruction of PET brain data in a PET/MR hybrid scanner is challenging in the absence of transmission sources, where MR images are used for MR-based attenuation correction (MR-AC). The main challenge of MR-AC is to separate bone and air, as neither have a signal in traditional MR images, and to assign the correct linear attenuation coefficient to bone. The ultra-short echo time (UTE) MR sequence was proposed as a basis for MR-AC as this sequence shows a small signal in bone. The purpose of this study was to develop a new clinically feasible MR-AC method with patient specific continuous-valued linear attenuation coefficients in bone that provides accurate reconstructed PET image data. A total of 164 [(18)F]FDG PET/MR patients were included in this study, of which 10 were used for training. MR-AC was based on either standard CT (reference), UTE or our method (RESOLUTE). The reconstructed PET images were evaluated in the whole brain, as well as regionally in the brain using a ROI-based analysis. Our method segments air, brain, cerebral spinal fluid, and soft tissue voxels on the unprocessed UTE TE images, and uses a mapping of R(*)2 values to CT Hounsfield Units (HU) to measure the density in bone voxels. The average error of our method in the brain was 0.1% and less than 1.2% in any region of the brain. On average 95% of the brain was within  ±10% of PETCT, compared to 72% when using UTE. The proposed method is clinically feasible, reducing both the global and local errors on the reconstructed PET images, as well as limiting the number and extent of the outliers.

  3. Region specific optimization of continuous linear attenuation coefficients based on UTE (RESOLUTE): application to PET/MR brain imaging

    NASA Astrophysics Data System (ADS)

    Ladefoged, Claes N.; Benoit, Didier; Law, Ian; Holm, Søren; Kjær, Andreas; Højgaard, Liselotte; Hansen, Adam E.; Andersen, Flemming L.

    2015-10-01

    The reconstruction of PET brain data in a PET/MR hybrid scanner is challenging in the absence of transmission sources, where MR images are used for MR-based attenuation correction (MR-AC). The main challenge of MR-AC is to separate bone and air, as neither have a signal in traditional MR images, and to assign the correct linear attenuation coefficient to bone. The ultra-short echo time (UTE) MR sequence was proposed as a basis for MR-AC as this sequence shows a small signal in bone. The purpose of this study was to develop a new clinically feasible MR-AC method with patient specific continuous-valued linear attenuation coefficients in bone that provides accurate reconstructed PET image data. A total of 164 [18F]FDG PET/MR patients were included in this study, of which 10 were used for training. MR-AC was based on either standard CT (reference), UTE or our method (RESOLUTE). The reconstructed PET images were evaluated in the whole brain, as well as regionally in the brain using a ROI-based analysis. Our method segments air, brain, cerebral spinal fluid, and soft tissue voxels on the unprocessed UTE TE images, and uses a mapping of R2* values to CT Hounsfield Units (HU) to measure the density in bone voxels. The average error of our method in the brain was 0.1% and less than 1.2% in any region of the brain. On average 95% of the brain was within  ±10% of PETCT, compared to 72% when using UTE. The proposed method is clinically feasible, reducing both the global and local errors on the reconstructed PET images, as well as limiting the number and extent of the outliers.

  4. Weight gain following subthalamic nucleus deep brain stimulation: a PET study.

    PubMed

    Sauleau, Paul; Le Jeune, Florence; Drapier, Sophie; Houvenaghel, Jean-François; Dondaine, Thibaut; Haegelen, Claire; Lalys, Florent; Robert, Gabriel; Drapier, Dominique; Vérin, Marc

    2014-12-01

    Several hypotheses have been put forward to explain weight gain after deep brain stimulation (DBS), but none provides a fully satisfactory account of this adverse effect. We analyzed the correlation between changes in brain metabolism (using positron emission tomography [PET] imaging) and weight gain after bilateral subthalamic nucleus DBS in patients with Parkinson's disease. Body mass index was calculated and brain activity prospectively measured using 2-deoxy-2[18F]fluoro-D-glucose 3 months before and 4 months after the start of subthalamic nucleus deep brain stimulation in 23 patients with Parkinson's disease. Motor complications (United Parkinson's Disease Rating Scale [UPDRS]-IV scores) and dopaminergic medication were included in the analysis to control for their possible influence on brain metabolism. Mean ± standard deviation (SD) body mass index increased significantly by 0.8 ± 1.5 kg/m(2) (P = 0.03). Correlations were found between weight gain and changes in brain metabolism in limbic and associative areas, including the orbitofrontal cortex (Brodmann areas [BAs] 10 and 11), lateral and medial parts of the temporal lobe (BAs 20, 21, 22,39 and 42), anterior cingulate cortex (BA 32), and retrosplenial cortex (BA 30). However, we found no correlation between weight gain and metabolic changes in sensorimotor areas. These findings suggest that changes in associative and limbic processes contribute to weight gain after subthalamic nucleus DBS in Parkinson's disease.

  5. Radionuclide labeling and evaluation of candidate radioligands for PET imaging of histone deacetylase in the brain.

    PubMed

    Seo, Young Jun; Muench, Lisa; Reid, Alicia; Chen, Jinzhu; Kang, Yeona; Hooker, Jacob M; Volkow, Nora D; Fowler, Joanna S; Kim, Sung Won

    2013-12-15

    Histone deacetylases (HDACs) regulate gene expression by inducing conformational changes in chromatin. Ever since the discovery of a naturally occurring HDAC inhibitor, trichostatin A (TSA) stimulated the recent development of suberoylanilide (SAHA, Zolinza®), HDAC has become an important molecular target for drug development. This has created the need to develop specific in vivo radioligands to study epigenetic regulation and HDAC engagement for drug development for diseases including cancer and psychiatric disorders. 6-([(18)F]Fluoroacetamido)-1-hexanoicanilide ([(18)F]FAHA) was recently developed as a HDAC substrate and shows moderate blood-brain barrier (BBB) permeability and specific signal (by metabolic trapping/or deacetylation) but rapid metabolism. Here, we report the radiosynthesis of two carbon-11 labeled candidate radiotracers (substrate- and inhibitor-based radioligand) for HDAC and their evaluation in non-human primate brain. PET studies showed very low brain uptake and rapid metabolism of both labeled compounds but revealed a surprising enhancement of brain penetration by F for H substitution when comparing one of these to [(18)F]FAHA. Further structural refinement is needed for the development of brain-penetrant, metabolically stable HDAC radiotracers and to understand the role of fluorine substitution on brain penetration.

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

    NASA Astrophysics Data System (ADS)

    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.

  7. Ligands for SPECT and PET imaging of muscarinic-cholinergic receptors of the heart and brain

    SciTech Connect

    Knapp, F.F. Jr.; McPherson, D.W.; Luo, H.

    1995-06-01

    Interest in the potential use of cerebral SPECT and PET imaging for determination of the density and activity of muscarinic-cholinergic receptors (mAChR) has been stimulated by the changes in these receptors which occur in many neurological diseases. In addition, the important involvement of mAChR in modulating negative inotropic cardiac activity suggests that such receptor ligands may have important applications in evaluation of changes which may occur in cardiac disease. In this paper, the properties of several key muscarinic receptor ligands being developed or which have been used for clinical SPECT and PET are discussed. In addition, the ORNL development of the new iodinated IQNP ligand based on QNB and the results of in vivo biodistribution studies in rats, in vitro competitive binding studies and ex vivo autoradiographic experiments are described. The use of radioiodinated IQNP may offer several advantages in comparison to IQNB because of its easy and high yield preparation and high brain uptake and the potential usefulness of the {open_quotes}partial{close_quotes} subtype selective IONP isomers. We also describe the development of new IQNP-type analogues which offer the opportunity for radiolabeling with positron-emitting radioisotopes (carbon-11, fluorine-18 and bromine-76) for potential use with PET.

  8. Designing a compact high performance brain PET scanner—simulation study

    NASA Astrophysics Data System (ADS)

    Gong, Kuang; Majewski, Stan; Kinahan, Paul E.; Harrison, Robert L.; Elston, Brian F.; Manjeshwar, Ravindra; Dolinsky, Sergei; Stolin, Alexander V.; Brefczynski-Lewis, Julie A.; Qi, Jinyi

    2016-05-01

    The desire to understand normal and disordered human brain function of upright, moving persons in natural environments motivates the development of the ambulatory micro-dose brain PET imager (AMPET). An ideal system would be light weight but with high sensitivity and spatial resolution, although these requirements are often in conflict with each other. One potential approach to meet the design goals is a compact brain-only imaging device with a head-sized aperture. However, a compact geometry increases parallax error in peripheral lines of response, which increases bias and variance in region of interest (ROI) quantification. Therefore, we performed simulation studies to search for the optimal system configuration and to evaluate the potential improvement in quantification performance over existing scanners. We used the Cramér-Rao variance bound to compare the performance for ROI quantification using different scanner geometries. The results show that while a smaller ring diameter can increase photon detection sensitivity and hence reduce the variance at the center of the field of view, it can also result in higher variance in peripheral regions when the length of detector crystal is 15 mm or more. This variance can be substantially reduced by adding depth-of-interaction (DOI) measurement capability to the detector modules. Our simulation study also shows that the relative performance depends on the size of the ROI, and a large ROI favors a compact geometry even without DOI information. Based on these results, we propose a compact ‘helmet’ design using detectors with DOI capability. Monte Carlo simulations show the helmet design can achieve four-fold higher sensitivity and resolve smaller features than existing cylindrical brain PET scanners. The simulations also suggest that improving TOF timing resolution from 400 ps to 200 ps also results in noticeable improvement in image quality, indicating better timing resolution is desirable for brain imaging.

  9. Imaging of sigma1 receptors in the human brain using PET and [11C]SA4503.

    PubMed

    Toyohara, Jun; Sakata, Muneyuki; Ishiwata, Kiichi

    2009-09-01

    Sigma(1) receptors were imaged in living human brain by positron emission tomography (PET) using [(11)C] SA4503. A dynamic 90-min scan and kinetic analysis enabled quantification of receptor density in the brain. The sigma(1) receptors were distributed throughout the brain in normal subjects, but decreased in the frontal, temporal, and occipital lobes, cerebellum and thalamus in patients with early Alzheimer's disease and in the putamen in patients with Parkinson's disease. In addition, rates of receptor occupancy by the neuroleptic haloperidol and the selective serotonin reuptake inhibitor fluvoxamine were evaluated by [(11)C]SA4503-PET and found to be high. [(11)C]SA4503-PET is useful for studying the pathophysiology of neurological and psychiatric disorders such as schizophrenia and for evaluation of the pharmacodynamics of psychiatric drugs.

  10. [11C]CHIBA-1001 as a Novel PET Ligand for α7 Nicotinic Receptors in the Brain: A PET Study in Conscious Monkeys

    PubMed Central

    Hashimoto, Kenji; Nishiyama, Shingo; Ohba, Hiroyuki; Matsuo, Masaaki; Kobashi, Tatsuhiko; Takahagi, Makoto; Iyo, Masaomi; Kitashoji, Takeru; Tsukada, Hideo

    2008-01-01

    Background The α7 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 α7 nAChRs in the intact human brain. Here we report the novel PET radioligand [11C]CHIBA-1001 for in vivo imaging of α7 nAChRs in the non-human primate brain. Methodology/Principal Findings A receptor binding assay showed that CHIBA-1001 was a highly selective ligand at α7 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 α7 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 α7 nAChR agonist SSR180711 (5.0 mg/kg). However, the distribution of [11C]CHIBA-1001 was not altered by pretreatment with the selective α4β2 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 α7 nAChRs in the intact brain of patients with neuropsychiatric diseases such as schizophrenia and Alzheimer's disease. PMID:18800169

  11. An open tool for input function estimation and quantification of dynamic PET FDG brain scans.

    PubMed

    Bertrán, Martín; Martínez, Natalia; Carbajal, Guillermo; Fernández, Alicia; Gómez, Álvaro

    2016-08-01

    Positron emission tomography (PET) analysis of clinical studies is mostly restricted to qualitative evaluation. Quantitative analysis of PET studies is highly desirable to be able to compute an objective measurement of the process of interest in order to evaluate treatment response and/or compare patient data. But implementation of quantitative analysis generally requires the determination of the input function: the arterial blood or plasma activity which indicates how much tracer is available for uptake in the brain. The purpose of our work was to share with the community an open software tool that can assist in the estimation of this input function, and the derivation of a quantitative map from the dynamic PET study. Arterial blood sampling during the PET study is the gold standard method to get the input function, but is uncomfortable and risky for the patient so it is rarely used in routine studies. To overcome the lack of a direct input function, different alternatives have been devised and are available in the literature. These alternatives derive the input function from the PET image itself (image-derived input function) or from data gathered from previous similar studies (population-based input function). In this article, we present ongoing work that includes the development of a software tool that integrates several methods with novel strategies for the segmentation of blood pools and parameter estimation. The tool is available as an extension to the 3D Slicer software. Tests on phantoms were conducted in order to validate the implemented methods. We evaluated the segmentation algorithms over a range of acquisition conditions and vasculature size. Input function estimation algorithms were evaluated against ground truth of the phantoms, as well as on their impact over the final quantification map. End-to-end use of the tool yields quantification maps with [Formula: see text] relative error in the estimated influx versus ground truth on phantoms. The main

  12. A Dual Tracer PET-MRI Protocol for the Quantitative Measure of Regional Brain Energy Substrates Uptake in the Rat

    PubMed Central

    Roy, Maggie; Nugent, Scott; Tremblay, Sébastien; Descoteaux, Maxime; Beaudoin, Jean-François; Tremblay, Luc; Lecomte, Roger; Cunnane, Stephen C

    2013-01-01

    We present a method for comparing the uptake of the brain's two key energy substrates: glucose and ketones (acetoacetate [AcAc] in this case) in the rat. The developed method is a small-animal positron emission tomography (PET) protocol, in which 11C-AcAc and 18F-fluorodeoxyglucose (18F-FDG) are injected sequentially in each animal. This dual tracer PET acquisition is possible because of the short half-life of 11C (20.4 min). The rats also undergo a magnetic resonance imaging (MRI) acquisition seven days before the PET protocol. Prior to image analysis, PET and MRI images are coregistered to allow the measurement of regional cerebral uptake (cortex, hippocampus, striatum, and cerebellum). A quantitative measure of 11C-AcAc and 18F-FDG brain uptake (cerebral metabolic rate; μmol/100 g/min) is determined by kinetic modeling using the image-derived input function (IDIF) method. Our new dual tracer PET protocol is robust and flexible; the two tracers used can be replaced by different radiotracers to evaluate other processes in the brain. Moreover, our protocol is applicable to the study of brain fuel supply in multiple conditions such as normal aging and neurodegenerative pathologies such as Alzheimer's and Parkinson's diseases. PMID:24430432

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

    PubMed

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

    2017-08-24

    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 which 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) for air and soft tissue and by using the linear relationship to generate a continuous LAC map for the bone. Additionally, for comparison purpose, 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 where the bone is ignored 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 gen- erated 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. © 2017 Institute of Physics and Engineering in Medicine.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    Benoit, Didier; Ladefoged, Claes N.; Rezaei, Ahmadreza; Keller, Sune H.; Andersen, Flemming L.; Højgaard, Liselotte; Hansen, Adam E.; Holm, Søren; Nuyts, Johan

    2016-12-01

    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 {αj} parameter is introduced and optimized in order to drive the algorithm to a final attenuation map most consistent with the emission data. Because the non-TOF MLAA is used, a technique to reduce the cross-talk effect is proposed. In this study, the proposed algorithm is compared to the common reconstruction methods such as OSEM using a CT attenuation map, considered as the reference, and OSEM using the Dixon and UTE attenuation maps. To show the robustness and the reproducibility of the proposed algorithm, a set of 204 [18F]FDG patients, 35 [11C]PiB patients and 1 [18F]FET patient are used. The results show that by choosing an optimized value of {αj} in MLTR, the proposed algorithm improves the results compared to the standard MR-based attenuation correction methods (i.e. OSEM using the Dixon or the UTE attenuation maps), and the cross-talk and the scale problem are limited.

  16. Tissue Probability-Based Attenuation Correction for Brain PET/MR by Using SPM8

    NASA Astrophysics Data System (ADS)

    Teuho, J.; Linden, J.; Johansson, J.; Tuisku, J.; Tuokkola, T.; Teräs, M.

    2016-10-01

    Bone attenuation remains a methodological challenge in hybrid PET/MR, as bone is hard to visualize via magnetic resonance imaging (MRI). Therefore, novel methods for taking into account bone attenuation in MR-based attenuation correction (MRAC) are needed. In this study, we propose a tissue-probability based attenuation correction (TPB-AC), which employs the commonly available neurological toolbox SPM8, to derive a subject-specific μ-map by segmentation of T1-weighted MR images. The procedures to derive a μ-map representing soft tissue, air and bone from the New Segment function in SPM8 and MATLAB are described. Visual and quantitative comparisons against CT-based attenuation correction (CTAC) data were performed using two μ-values ( 0.135 cm-1 and 0.145 cm-1) for bone. Results show improvement of visual quality and quantitative accuracy of positron emission tomography (PET) images when TPB-AC μ-map is used in PET/MR image reconstruction. Underestimation in PET images was decreased by an average of 5 ±2 percent in the whole brain across all patients. In addition, the method performed well when compared to CTAC, with maximum differences (mean ± standard deviation) of - 3 ±2 percent and 2 ±4 percent in two regions out of 28. Finally, the method is simple and computationally efficient, offering a promising platform for further development. Therefore, a subject-specific MR-based μ-map can be derived only from the tissue probability maps from the New Segment function of SPM8.

  17. Methods for the correction of vascular artifacts in PET O-15 water brain-mapping studies

    SciTech Connect

    Chen, K.; Reiman, E.M. |; Lawson, M.; Yun, L.S.; Bandy, D.

    1996-12-01

    While positron emission tomographic (PET) measurements of regional cerebral blood flow (rCBF) can be used to map brain regions that are involved in normal and pathological human behaviors, measurements in the anteromedial temporal lobe can be confounded by the combined effects of radiotracer activity in neighboring arteries and partial-volume averaging. The authors now describe two simple methods to address this vascular artifact. One method utilizes the early frames of a dynamic PET study, while the other method utilizes a coregistered magnetic resonance image (MRI) to characterize the vascular region of interest (VROI). Both methods subsequently assign a common value to each pixel in the VROI for the control scan and the activation scan. To study the vascular artifact and to demonstrate the ability of the proposed methods correcting the vascular artifact, four dynamic PET scans were performed in a single subject during the same behavioral state. For each of the four scans, a vascular scan containing vascular activity was computed as the summation of the images acquired 0--60 s after radiotracer administrations, and a control scan containing minimal vascular activity was computed as the summation of the images acquired 20--80 s after radiotracer administration. t-score maps calculated from the four pairs of vascular and control scans were used to characterize regional blood flow differences related to vascular activity before and after the applications of each vascular artifact correction method. Both methods eliminated the observed differences in vascular activity, as well as the vascular artifact observed in the anteromedial temporal lobes. Using PET data from a study of normal human emotion, these methods permitted us to identify rCBF increases in the anteromedial temporal lobe free from the potentially confounding, combined effects of vascular activity and partial-volume averaging.

  18. Application of single- and dual-energy CT brain tissue segmentation to PET monitoring of proton therapy

    NASA Astrophysics Data System (ADS)

    Berndt, Bianca; Landry, Guillaume; Schwarz, Florian; Tessonnier, Thomas; Kamp, Florian; Dedes, George; Thieke, Christian; Würl, Matthias; Kurz, Christopher; Ganswindt, Ute; Verhaegen, Frank; Debus, Jürgen; Belka, Claus; Sommer, Wieland; Reiser, Maximilian; Bauer, Julia; Parodi, Katia

    2017-03-01

    The purpose of this work was to evaluate the ability of single and dual energy computed tomography (SECT, DECT) to estimate tissue composition and density for usage in Monte Carlo (MC) simulations of irradiation induced β + activity distributions. This was done to assess the impact on positron emission tomography (PET) range verification in proton therapy. A DECT-based brain tissue segmentation method was developed for white matter (WM), grey matter (GM) and cerebrospinal fluid (CSF). The elemental composition of reference tissues was assigned to closest CT numbers in DECT space (DECTdist). The method was also applied to SECT data (SECTdist). In a validation experiment, the proton irradiation induced PET activity of three brain equivalent solutions (BES) was compared to simulations based on different tissue segmentations. Five patients scanned with a dual source DECT scanner were analyzed to compare the different segmentation methods. A single magnetic resonance (MR) scan was used for comparison with an established segmentation toolkit. Additionally, one patient with SECT and post-treatment PET scans was investigated. For BES, DECTdist and SECTdist reduced differences to the reference simulation by up to 62% when compared to the conventional stoichiometric segmentation (SECTSchneider). In comparison to MR brain segmentation, Dice similarity coefficients for WM, GM and CSF were 0.61, 0.67 and 0.66 for DECTdist and 0.54, 0.41 and 0.66 for SECTdist. MC simulations of PET treatment verification in patients showed important differences between DECTdist/SECTdist and SECTSchneider for patients with large CSF areas within the treatment field but not in WM and GM. Differences could be misinterpreted as PET derived range shifts of up to 4 mm. DECTdist and SECTdist yielded comparable activity distributions, and comparison of SECTdist to a measured patient PET scan showed improved agreement when compared to SECTSchneider. The agreement between predicted and measured PET

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

    NASA Astrophysics Data System (ADS)

    da Silva, N. A.; Herzog, H.; Weirich, C.; Tellmann, L.; Rota Kops, E.; Hautzel, H.; Almeida, P.

    2013-02-01

    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.

  20. [The brain mechanism of error detection: the P.E.T. study].

    PubMed

    Kireev, M V; Korotkov, A D; Poliakov, Iu I; Anichkov, A D; Medvedev, S V

    2011-10-01

    In present research, the brain maintenance of the error detection mechanism was studied in resting condition and while subjects consciously implemented incorrect actions (i.e. deception). Assessment of the regional cerebral blood flow revealed involvement of anterior cingulated cortex in deception. The obtained data indicate that it is impossible to consciously control the activity of the error detection mechanism. PET study of patients with obsessive compulsive disorder in resting condition revealed a decrease of brain glucose metabolism in the anterior cingulated cortex in comparison with healthy subjects. These data pointed to malfunctioning of the error detection mechanism. The findings support the formerly proposed hypothesis about the impact of the error detection mechanism in formation and support of obsessive compulsive disorder.

  1. Joint factor and kinetic analysis of dynamic FDOPA PET scans of brain cancer patients.

    PubMed

    Dowson, N; Bourgeat, P; Rose, S; Daglish, M; Smith, J; Fay, M; Coulthard, A; Winter, C; MacFarlane, D; Thomas, P; Crozier, S; Salvado, O

    2010-01-01

    Kinetic analysis is an essential tool of Positron Emission Tomography image analysis. However it requires a pure tissue time activity curve (TAC) in order to calculate the system parameters. Pure tissue TACs are particularly difficult to obtain in the brain as the low resolution of PET means almost all voxels are a mixture of tissues. Factor analysis explicitly accounts for mixing but is an underdetermined problem that can give arbitrary results. A joint factor and kinetic analysis is proposed whereby factor analysis explicitly accounts for mixing of tissues. Hence, more meaningful parameters are obtained by the kinetic models, which also ensure a less ambiguous solution to the factor analysis. The method was tested using a cylindrical phantom and the 18F-DOPA data of a brain cancer patient.

  2. Functional pattern of brain FDG-PET in amyotrophic lateral sclerosis.

    PubMed

    Pagani, Marco; Chiò, Adriano; Valentini, Maria Consuelo; Öberg, Johanna; Nobili, Flavio; Calvo, Andrea; Moglia, Cristina; Bertuzzo, Davide; Morbelli, Silvia; De Carli, Fabrizio; Fania, Piercarlo; Cistaro, Angelina

    2014-09-16

    We investigated a large sample of patients with amyotrophic lateral sclerosis (ALS) at rest in order to assess the value of (18)F-2-fluoro-2-deoxy-d-glucose ((18)F-FDG) PET as a biomarker to discriminate patients from controls. A total of 195 patients with ALS and 40 controls underwent brain (18)F-FDG-PET, most within 5 months of diagnosis. Spinal and bulbar subgroups of ALS were also investigated. Twenty-five bilateral cortical and subcortical volumes of interest and cerebellum were taken into account, and (18)F-FDG uptakes were individually normalized by whole-brain values. Group analyses investigated the ALS-related metabolic changes. Discriminant analysis investigating sensitivity and specificity was performed using the 51 volumes of interest as well as age and sex. Metabolic connectivity was explored by voxel-wise interregional correlation analysis. Hypometabolism was found in frontal, motor, and occipital cortex and hypermetabolism in midbrain, temporal pole, and hippocampus in patients with ALS compared to controls. A similar metabolic pattern was also found in the 2 subgroups. Discriminant analysis showed a sensitivity of 95% and a specificity of 83% in separating patients from controls. Connectivity analysis found a highly significant positive correlation between midbrain and white matter in corticospinal tracts in patients with ALS. (18)F-FDG distribution changes in ALS showed a clear pattern of hypometabolism in frontal and occipital cortex and hypermetabolism in midbrain. The latter might be interpreted as the neurobiological correlate of diffuse subcortical gliosis. Discriminant analysis resulted in high sensitivity and specificity in differentiating patients with ALS from controls. Once validated by diseased-control studies, the present methodology might represent a potentially useful biomarker for ALS diagnosis. This study provides Class III evidence that (18)F-FDG-PET accurately distinguishes patients with ALS from normal controls (sensitivity 95

  3. PET and SPECT in whiplash syndrome: a new approach to a forgotten brain?

    PubMed Central

    Otte, A; Ettlin, T; Nitzsche, E; Wachter, K; Hoegerle, S; Simon, G; Fierz, L; Moser, E; Mueller-Brand, J

    1997-01-01

    Whiplash associated disorders are a medicolegally controversial condition becoming increasingly worrisome in the western world. This study was designed to evaluate perfusion and glucose metabolism in whiplash brain. Using Tc-99m-bicisate (ECD) single photon emission computed tomography (SPECT) and F-18-fluorodeoxyglucose (FDG) PET, six clinically and neuropsychologically controlled patients (patient group) with whiplash syndrome and 12 normal controls (control group) were investigated. Standardised elliptical regions of interest (ROIs) were determined in three adjacent transaxial slices in the frontal, parietal, temporal, and parieto-occipital cortex, cerebellum, brain stem, basal ganglia, and thalamus. For PET, the glucose metabolic index (GMI; =ROI uptake/global uptake at the level of the basal ganglia) and, for SPECT, the perfusion index (PI; =ROI/global) were calculated. In the patient group there was significant hypometabolism and hypoperfusion in the parieto-occipital regions (on the right (R) and left (L) side) compared with the control group: PET data: GMI parieto-occipital R: control 1.066 (0.081) (mean (SD)), patient 0.946 (0.065); P=0.0092, Mann Whitney. GMI parieto-occipital L: control 1.034 (0.051), patient 0.922 (0.073); p=0.0067. SPECT data: PI parieto-occipital R: control 1.262 (0.066), patient 1.102 (0.063); P=0.0039. PI parieto-occipital L: control 1.226 (0.095), patient 1.098 (0.075); P=0.0273. In some patients there was hypometabolism (>2 SD of control) in regions other than the parieto-occipital region. It is hypothesised that parieto-occipital hypometabolism may be caused by activation of nociceptive afferent nerves from the upper cervical spine.

 PMID:9328255

  4. 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.

    PubMed

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

    2017-10-10

    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 (<2 cm) repositioning the phantom and all scans (12 replicates for IQ phantom and 10 replicates for Hoffman brain phantom) were performed at equal count statistics. For the NEMA IQ phantom, we studied the recovery coefficients (RC) of the maximum (SUVmax ), peak (SUVpeak ) and mean (SUVmean ) uptake in each sphere as a function of experimental conditions (noise level, reconstruction settings and phantom repositioning). For the 3D Hoffman phantom, the mean activity concentration was determined within several volumes of interest and activity recovery and its precision was studied as function of experimental conditions. The impact of phantom repositioning on RC precision was mainly seen on the Philips Ingenuity PET/CT, especially in the case of smaller spheres (<17mm diameter, P<0.05). This effect was much smaller for the Siemens Biograph system. When exploring SUVmax , SUVpeak or SUVmean of the spheres in the NEMA IQ phantom, it was observed that precision depended on phantom repositioning, reconstruction algorithm and scan duration, with SUVmax being most and SUVpeak least sensitive to phantom repositioning. For the brain phantom, regional averaged SUVs were only minimally affected by phantom repositioning (<2 cm). The precision of quantitative PET metrics depends on the combination of reconstruction protocol, data analysis methods and scan duration (scan statistics). Moreover

  5. Accuracy of distinguishing between dysembryoplastic neuroepithelial tumors and other epileptogenic brain neoplasms with [¹¹C]methionine PET.

    PubMed

    Rheims, Sylvain; Rubi, Sebastià; Bouvard, Sandrine; Bernard, Emilien; Streichenberger, Nathalie; Guenot, Marc; Le Bars, Didier; Hammers, Alexander; Ryvlin, Philippe

    2014-10-01

    Dysembryoplastic neuroepithelial tumors (DNTs) represent a prevalent cause of epileptogenic brain tumors, the natural evolution of which is much more benign than that of most gliomas. Previous studies have suggested that [(11)C]methionine positron emission tomography (MET-PET) could help to distinguish DNTs from other epileptogenic brain tumors, and hence optimize the management of patients. Here, we reassessed the diagnostic accuracy of MET-PET for the differentiation between DNT and other epileptogenic brain neoplasms in a larger population. We conducted a retrospective study of 77 patients with focal epilepsy related to a nonrapidly progressing brain tumor on MRI who underwent MET-PET, including 52 with a definite histopathology. MET-PET data were assessed by a structured visual analysis that distinguished normal, moderately abnormal, and markedly abnormal tumor methionine uptake and by semiquantitative ratio measurements. Pathology showed 21 DNTs (40%), 10 gangliogliomas (19%), 19 low-grade gliomas (37%), and 2 high-grade gliomas (4%). MET-PET visual findings significantly differed among the various tumor types (P < .001), as confirmed by semiquantitative analyses (P < .001 for all calculated ratios), regardless of gadolinium enhancement on MRI. All gliomas and gangliogliomas were associated with moderately or markedly increased tumor methionine uptake, whereas 9/21 DNTs had normal methionine uptake. Receiver operating characteristics analysis of the semiquantitative ratios showed an optimal cutoff threshold that distinguished DNTs from other tumor types with 90% specificity and 89% sensitivity. Normal MET-PET findings in patients with an epileptogenic nonrapidly progressing brain tumor are highly suggestive of DNT, whereas a markedly increased tumor methionine uptake makes this diagnosis unlikely. © The Author(s) 2014. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e

  6. Accuracy of distinguishing between dysembryoplastic neuroepithelial tumors and other epileptogenic brain neoplasms with [11C]methionine PET

    PubMed Central

    Rheims, Sylvain; Rubi, Sebastià; Bouvard, Sandrine; Bernard, Emilien; Streichenberger, Nathalie; Guenot, Marc; Le Bars, Didier; Hammers, Alexander; Ryvlin, Philippe

    2014-01-01

    Background Dysembryoplastic neuroepithelial tumors (DNTs) represent a prevalent cause of epileptogenic brain tumors, the natural evolution of which is much more benign than that of most gliomas. Previous studies have suggested that [11C]methionine positron emission tomography (MET-PET) could help to distinguish DNTs from other epileptogenic brain tumors, and hence optimize the management of patients. Here, we reassessed the diagnostic accuracy of MET-PET for the differentiation between DNT and other epileptogenic brain neoplasms in a larger population. Methods We conducted a retrospective study of 77 patients with focal epilepsy related to a nonrapidly progressing brain tumor on MRI who underwent MET-PET, including 52 with a definite histopathology. MET-PET data were assessed by a structured visual analysis that distinguished normal, moderately abnormal, and markedly abnormal tumor methionine uptake and by semiquantitative ratio measurements. Results Pathology showed 21 DNTs (40%), 10 gangliogliomas (19%), 19 low-grade gliomas (37%), and 2 high-grade gliomas (4%). MET-PET visual findings significantly differed among the various tumor types (P < .001), as confirmed by semiquantitative analyses (P < .001 for all calculated ratios), regardless of gadolinium enhancement on MRI. All gliomas and gangliogliomas were associated with moderately or markedly increased tumor methionine uptake, whereas 9/21 DNTs had normal methionine uptake. Receiver operating characteristics analysis of the semiquantitative ratios showed an optimal cutoff threshold that distinguished DNTs from other tumor types with 90% specificity and 89% sensitivity. Conclusions Normal MET-PET findings in patients with an epileptogenic nonrapidly progressing brain tumor are highly suggestive of DNT, whereas a markedly increased tumor methionine uptake makes this diagnosis unlikely. PMID:24598358

  7. Brain metabolic changes in Hodgkin disease patients following diagnosis and during the disease course: An 18F-FDG PET/CT study

    PubMed Central

    CHIARAVALLOTI, AGOSTINO; PAGANI, MARCO; CANTONETTI, MARIA; DI PIETRO, BARBARA; TAVOLOZZA, MARIO; TRAVASCIO, LAURA; DI BIAGIO, DANIELE; DANIELI, ROBERTA; SCHILLACI, ORAZIO

    2015-01-01

    The aim of the present study was to investigate brain glucose metabolism in patients with Hodgkin disease (HD) after diagnosis and during chemotherapy treatment. Following the administration of first-line doxorubicin, bleomycin, vinblastine and dacarbazine (ABVD) chemotherapy, 74 HD patients underwent 18F-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography (PET)/computed tomography brain scans, both baseline (PET0) and interim (PET2) at the Department of Biomedicine and Prevention, University of Rome Tor Vergata (Rome, Italy). Fifty-seven patients were further evaluated 15±6 days after four additional cycles (PET6). Furthermore, a control group (CG) of 40 chemotherapy-naïve subjects was enrolled. Differences in brain 18F-FDG uptake between the CG, PET0, PET2 and PET6 scans were analyzed using statistical parametric mapping. Compared with the PET0 and CG scans, the PET2 scan demonstrated a higher metabolic activity in Brodmann area (BA) 39, and a metabolic reduction in BA 11 bilaterally and in left BA 32. All of these changes disappeared at PET6. The results of the present study indicate that ABVD chemotherapy has a limited impact on brain metabolism. PMID:25621038

  8. Comparison of FDG-PET findings of brain metastasis from non-small-cell lung cancer and small-cell lung cancer.

    PubMed

    Lee, Ho-Young; Chung, June-Key; Jeong, Jae Min; Lee, Dong Soo; Kim, Dong Gyu; Jung, Hee Won; Lee, Myung Chul

    2008-05-01

    We compared the F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) findings of brain metastasis between patients with non-small-cell lung cancer (NSCLC) and small cell lung cancer (SCLC). A whole-body FDG and a brain PET were performed in 48 patients (31 men, 17 women; 57 +/- 9 years, 42 NSCLC, 6 SCLC), who had brain metastasis on magnetic resonance (MR). All primary lung lesions were detected by FDG-PET and confirmed pathologically. We analyzed the PET findings, lesion sizes, and the pathological result of primary lung cancer. Of the 48 patients, 31 (64.6%) showed hypermetabolic lesions on FDG-PET of the brain image, and 14 (29.2%) showed hypometabolic lesions. Three patients (6.3%) had both hypermetabolic and hypometabolic lesions. On the lesion-based analysis, 74 lesions (67.3%) showed hypermetabolism on FDG-PET, and 36 lesions (32.7%) showed hypometabolism. All primary lung lesions were hypermetabolic on FDG-PET. When the FDG findings of metastatic brain lesions were analyzed with the pathological types of primary lung cancer, NSCLC was more frequently associated with hypermetabolic metastatic brain lesions than SCLC (80% and 26.7%, respectively, P < 0.01). On comparing the sizes of metastatic lesions between SCLC (1.3 +/- 1.2 cm) and NSCLC (1.8 +/- 1.2 cm), lesions of <1 cm were more frequent in SCLC than in NSCLC (P = 0.012). But no significant relationship was found between the size and PET finding of metastatic lesion (P = 0.412). Even when the primary lesion of lung cancer showed hypermetabolism in FDG-PET, FDG accumulation in metastatic brain lesions was variable. One-third of brain metastases from lung cancer showed hypometabolism. NSCLC was more frequently associated with hypermetabolic metastatic brain lesions than SCLC. The PET findings of brain lesions were affected not only by the size of lesion but also by its biological characteristics.

  9. Preclinical Properties of 18F-AV-45: A PET Agent for Aβ Plaques in the Brain

    PubMed Central

    Choi, Seok Rye; Golding, Geoff; Zhuang, Zhiping; Zhang, Wei; Lim, Nathaniel; Hefti, Franz; Benedum, Tyler E.; Kilbourn, Michael R.; Skovronsky, Daniel; Kung, Hank F.

    2011-01-01

    β-amyloid plaques (Aβ plaques) in the brain, containing predominantly fibrillary Aβ peptide aggregates, represent a defining pathologic feature of Alzheimer disease (AD). Imaging agents targeting the Aβ plaques in the living human brain are potentially valuable as biomarkers of pathogenesis processes in AD. (E)-4-(2-(6-(2-(2-(2-18F-fluoroethoxy)ethoxy)ethoxy)pyridin-3-yl)vinyl)-N-methyl benzenamine (18F-AV-45) is such as an agent currently in phase III clinical studies for PET of Aβ plaques in the brain. Methods In vitro binding of 18F-AV-45 to Aβ plaques in the postmortem AD brain tissue was evaluated by in vitro binding assay and autoradiography. In vivo biodistribution of 18F-AV-45 in mice and ex vivo autoradiography of AD transgenic mice (APPswe/PSEN1) with Aβ aggregates in the brain were performed. Small-animal PET of a monkey brain after an intravenous injection of 18F-AV-45 was evaluated. Results 18F-AV-45 displayed a high binding affinity and specificity to Aβ plaques (Kd, 3.72 ± 0.30 nM). In vitro autoradiography of postmortem human brain sections showed substantial plaque labeling in AD brains and not in the control brains. Initial high brain uptake and rapid washout from the brain of healthy mice and monkey were observed. Metabolites produced in the blood of healthy mice after an intravenous injection were identified. 18F-AV-45 displayed excellent binding affinity to Aβ plaques in the AD brain by ex vivo autoradiography in transgenic AD model mice. The results lend support that 18F-AV-45 may be a useful PET agent for detecting Aβ plaques in the living human brain. PMID:19837759

  10. Long-term effects of 'ecstasy' abuse on the human brain studied by FDG PET.

    PubMed

    Buchert, R; Obrocki, J; Thomasius, R; Väterlein, O; Petersen, K; Jenicke, L; Bohuslavizki, K H; Clausen, M

    2001-08-01

    The popular recreational drug, 'ecstasy', mainly contains 3,4-methylenedioxymethamphetamine (MDMA) as the psychotropic agent. MDMA is suspected of causing neurotoxic lesions to the serotonergic system as demonstrated by animal studies, examinations of human cerebrospinal fluid, and the first positron emission tomography (PET) studies using the serotonin transporter ligand [11C]-McN5652. Damage of serotonergic afferents might mediate long-lasting alterations of cerebral glucose metabolism as a secondary effect. To study a relationship between ecstasy use and long-lasting alterations, PET using 2-[18F]-fluoro-2-deoxy-d-glucose (FDG) was performed in 93 ecstasy users and 27 subjects without any known history of illicit-drug abuse. As an index of glucose metabolism, mean normalized FDG uptake was determined in both groups using a computerized brain atlas, and was compared for a selected number of brain regions. FDG uptake was normalized in each individual by dividing local FDG uptake by the maximum FDG uptake in the individual's brain. Within the group of ecstasy users we examined the relationship between FDG uptake and cumulative ecstasy dose, time since last ecstasy ingestion at the time of PET scanning, and age at first ecstasy use, respectively. Normalized FDG uptake was reduced within the striatum and amygdala of ecstasy users when compared to controls. No statistically significant correlation of the FDG uptake and the cumulative dose of ecstasy was detected. A positive correlation was found in the cingulate between FDG uptake and the time since last ecstasy ingestion. As compared to the control group, normalized FDG uptake in the cingulate was reduced in ecstasy users who took ecstasy during the last 6 months, while it was elevated in former ecstasy users who did not consume ecstasy for more than 1 year. FDG uptake was significantly more affected in ecstasy users who started to consume ecstasy before the age of 18 years. In conclusion, ecstasy abuse causes long

  11. Plasma Based Markers of [11C] PiB-PET Brain Amyloid Burden

    PubMed Central

    Kiddle, Steven John; Thambisetty, Madhav; Simmons, Andrew; Riddoch-Contreras, Joanna; Hye, Abdul; Westman, Eric; Pike, Ian; Ward, Malcolm; Johnston, Caroline; Lupton, Michelle Katharine; Lunnon, Katie; Soininen, Hilkka; Kloszewska, Iwona; Tsolaki, Magda; Vellas, Bruno; Mecocci, Patrizia; Lovestone, Simon

    2012-01-01

    Changes in brain amyloid burden have been shown to relate to Alzheimer's disease pathology, and are believed to precede the development of cognitive decline. There is thus a need for inexpensive and non-invasive screening methods that are able to accurately estimate brain amyloid burden as a marker of Alzheimer's disease. One potential method would involve using demographic information and measurements on plasma samples to establish biomarkers of brain amyloid burden; in this study data from the Alzheimer's Disease Neuroimaging Initiative was used to explore this possibility. Sixteen of the analytes on the Rules Based Medicine Human Discovery Multi-Analyte Profile 1.0 panel were found to associate with [11C]-PiB PET measurements. Some of these markers of brain amyloid burden were also found to associate with other AD related phenotypes. Thirteen of these markers of brain amyloid burden – c-peptide, fibrinogen, alpha-1-antitrypsin, pancreatic polypeptide, complement C3, vitronectin, cortisol, AXL receptor kinase, interleukin-3, interleukin-13, matrix metalloproteinase-9 total, apolipoprotein E and immunoglobulin E – were used along with co-variates in multiple linear regression, and were shown by cross-validation to explain >30% of the variance of brain amyloid burden. When a threshold was used to classify subjects as PiB positive, the regression model was found to predict actual PiB positive individuals with a sensitivity of 0.918 and a specificity of 0.545. The number of APOE ϵ 4 alleles and plasma apolipoprotein E level were found to contribute most to this model, and the relationship between these variables and brain amyloid burden was explored. PMID:23028511

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

    NASA Astrophysics Data System (ADS)

    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.

  13. The clinical impact of SPECT/PET co-registration with MRI in patients with brain tumors

    SciTech Connect

    Macapinlac, H.A.; Scott, A.M.; Zhang, J.J.

    1994-05-01

    We wanted to evaluate the clinical impact of co-registering SPECT and PET images with MRI (Gd-DTPA) in brain tumor patients. 81 patients with known or suspected brain tumors had 168 SPECT and/or PET scans which were difficult to interpret were coregistered with MRI. A modified Pellizari/Chen surface matching algorithm was used to fit the SPECT/PET and MR images. Impact of the technique on interpretation of the scans was defined as (A) no effect, (B) moderate effect (better localize abnormal uptake to suspected tumor and distinguish normal activity from tumor), (C) basis for final interpretation (distinguish tumor from necrosis, localize biopsy site, find occult tumor, grading of tumor). Impact on patient management was defined as (A) no effect, (B) altered diagnostic/treatment decision (continuation of conservative care, or justify chemo or radiation), (C) basis for treatment (direct biopsy, surgery, and/or radiation).

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

    PubMed

    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.

  15. Radionecrosis versus disease progression in brain metastasis. Value of (18)F-DOPA PET/CT/MRI.

    PubMed

    Hernández Pinzón, J; Mena, D; Aguilar, M; Biafore, F; Recondo, G; Bastianello, M

    2016-01-01

    The use of (18)F-DOPA PET/CT with magnetic resonance imaging fusion and the use of visual methods and quantitative analysis helps to differentiate between changes post-radiosurgery vs. suspicion of disease progression in a patient with brain metastases from melanoma, thus facilitating taking early surgical action.

  16. A high resolution prototype small-animal PET scanner dedicated to mouse brain imaging

    PubMed Central

    Yang, Yongfeng; Bec, Julien; Zhou, Jian; Zhang, Mengxi; Judenhofer, Martin S; Bai, Xiaowei; Di, Kun; Wu, Yibao; Rodriguez, Mercedes; Dokhale, Purushottam; Shah, Kanai S.; Farrell, Richard; Qi, Jinyi; Cherry, Simon R.

    2017-01-01

    A prototype small-animal PET scanner was developed based on depth-encoding detectors using dual-ended readout of very small scintillator elements to produce high and uniform spatial resolution suitable for imaging the mouse brain. Methods The scanner consists of 16 tapered dual-ended readout detectors arranged in a ring of diameter 61 mm. The axial field of view is 7 mm and the transaxial field of view is 30 mm. The scintillator arrays consist of 14×14 lutetium oxyorthosilicate (LSO) elements, with a crystal size of 0.43×0.43 mm2 at the front end and 0.80×0.43 mm2 at the back end, and the crystal elements are 13 mm long. The arrays are read out by 8×8 mm2 and a 13×8 mm2 position-sensitive avalanche photodiodes (PSAPDs) placed at opposite ends of the array. Standard nuclear instrumentation module (NIM) electronics and a custom designed multiplexer are used for signal processing. Results The detector performance was measured and all except the very edge crystals could be clearly resolved. The average detector intrinsic spatial resolution in the axial direction was 0.61 mm. A depth of interaction resolution of 1.7 mm was achieved. The sensitivity of the scanner at center of the field of view was 1.02% for a lower energy threshold of 150 keV and 0.68% for a lower energy threshold of 250 keV. The spatial resolution within a field of view that can accommodate the entire mouse brain was ~0.6 mm using a 3D Maximum Likelihood-Expectation Maximization (ML-EM) reconstruction algorithm. Images of a micro hot-rod phantom showed that rods with diameter down to 0.5 mm could be resolved. First in vivo studies were obtained using 18F-fluoride and confirmed that 0.6 mm resolution can be achieved in the mouse head in vivo. Brain imaging studies with 18F-fluorodeoxyglucose were also acquired. Conclusion A prototype PET scanner achieving a spatial resolution approaching the physical limits for a small-bore PET scanner set by positron range and acolinearity was developed. Future

  17. Quantitative imaging of protein targets in the human brain with PET

    NASA Astrophysics Data System (ADS)

    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

  18. Imaging Epigenetic Regulation by Histone Deacetylases in the Brain using PET/MRI with 18F-FAHA

    PubMed Central

    Yeh, Hsien-Hsien; Tian, Mei; Hinz, Rainer; Young, Daniel; Shavrin, Alexander; Mukhapadhyay, Uday; Flores, Leo G.; Balatoni, Julius; Soghomonyan, Suren; Jeong, Hwan J.; Pal, Ashutosh; Uthamanthil, Rajesh; Jackson, James N.; Nishii, Ryuichi; Mizuma, Hiroshi; Onoe, Hirotaka; Kagawa, Shinya; Higashi, Tatsuya; Fukumitsu, Nobuyoshi; Alauddin, Mian; Tong, William; Herholz, Karl; Gelovani, Juri G.

    2012-01-01

    Epigenetic modifications mediated by histone deacetylases (HDACs) play important roles in the mechanisms of different neurologic diseases and HDAC inhibitors (HDACIs) have shown promise in therapy. However, pharmacodynamic profiles of many HDACIs in the brain remain largely unknown due to the lack of validated methods for noninvasive imaging of HDACs expression-activity. In this study, dynamic PET/CT imaging was performed in 4 rhesus macaques using [18F]FAHA, a novel HDAC substrate, and [18F]fluoroacetate, the major radio-metabolite of [18F]FAHA, and fused with corresponding MR images of the brain. Quantification of [18F]FAHA accumulation in the brain was performed using a customized dual-tracer pharmacokinetic model. Immunohistochemical analyses of brain tissue revealed the heterogeneity of expression of individual HDACs in different brain structures and cell types and confirmed that PET/CT/MRI with [18F]FAHA reflects the level of expression-activity of HDAC class IIa enzymes. Furthermore, PET/CT/MRI with [18F]FAHA enabled non-invasive, quantitative assessment of pharmacodynamics of HDACs inhibitor SAHA in the brain. PMID:22995777

  19. Including anatomical and functional information in MC simulation of PET and SPECT brain studies. Brain-VISET: a voxel-based iterative method.

    PubMed

    Marti-Fuster, Berta; Esteban, Oscar; Thielemans, Kris; Setoain, Xavier; Santos, Andres; Ros, Domenec; Pavia, Javier

    2014-10-01

    Monte Carlo (MC) simulation provides a flexible and robust framework to efficiently evaluate and optimize image processing methods in emission tomography. In this work we present Brain-VISET (Voxel-based Iterative Simulation for Emission Tomography), a method that aims to simulate realistic [ (99m) Tc]-SPECT and [ (18) F]-PET brain databases by including anatomical and functional information. To this end, activity and attenuation maps generated using high-resolution anatomical images from patients were used as input maps in a MC projector to simulate SPECT or PET sinograms. The reconstructed images were compared with the corresponding real SPECT or PET studies in an iterative process where the activity inputs maps were being modified at each iteration. Datasets of 30 refractory epileptic patients were used to assess the new method. Each set consisted of structural images (MRI and CT) and functional studies (SPECT and PET), thereby allowing the inclusion of anatomical and functional variability in the simulation input models. SPECT and PET sinograms were obtained using the SimSET package and were reconstructed with the same protocols as those employed for the clinical studies. The convergence of Brain-VISET was evaluated by studying the behavior throughout iterations of the correlation coefficient, the quotient image histogram and a ROI analysis comparing simulated with real studies. The realism of generated maps was also evaluated. Our findings show that Brain-VISET is able to generate realistic SPECT and PET studies and that four iterations is a suitable number of iterations to guarantee a good agreement between simulated and real studies.

  20. 18F-FDG PET brain images as features for Alzheimer classification

    NASA Astrophysics Data System (ADS)

    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).

  1. Positron emission tomography (PET) studies of dopaminergic/cholinergic interactions in the baboon brain

    SciTech Connect

    Dewey, S.L.; Brodie, J.D.; Fowler, J.S.; MacGregor, R.R.; Schlyer, D.J.; King, P.T.; Alexoff, D.L.; Volkow, N.D.; Shiue, C.Y.; Wolf, A.P. )

    1990-01-01

    Interactions between the dopaminergic D2 receptor system and the muscarinic cholinergic system in the corpus striatum of adult female baboons (Papio anubis) were examined using positron emission tomography (PET) combined with (18F)N-methylspiroperidol (( 18F)NMSP) (to probe D2 receptor availability) and (N-11C-methyl)benztropine (to probe muscarinic cholinergic receptor availability). Pretreatment with benztropine, a long-lasting anticholinergic drug, bilaterally reduced the incorporation of radioactivity in the corpus striatum but did not alter that observed in the cerebellum or the rate of metabolism of (18F)NMSP in plasma. Pretreatment with unlabelled NMSP, a potent dopaminergic antagonist, reduced the incorporation of (N-11C-methyl)benztropine in all brain regions, with the greatest effect being in the corpus striatum greater than cortex greater than thalamus greater than cerebellum, but did not alter the rate of metabolism of the labelled benztropine in the plasma. These reductions in the incorporation of either (18F)NMSP or (N-11C-methyl)benztropine exceeded the normal variation in tracer incorporation in repeated studies in the same animal. This study demonstrates that PET can be used as a tool for investigating interactions between neurochemically different yet functionally linked neurotransmitters systems in vivo and provides insight into the consequences of multiple pharmacologic administration.

  2. Marker-less multi-frame motion tracking and compensation in PET-brain imaging

    NASA Astrophysics Data System (ADS)

    Lindsay, C.; Mukherjee, J. M.; Johnson, K.; Olivier, P.; Song, X.; Shao, L.; King, M. A.

    2015-03-01

    In PET brain imaging, patient motion can contribute significantly to the degradation of image quality potentially leading to diagnostic and therapeutic problems. To mitigate the image artifacts resulting from patient motion, motion must be detected and tracked then provided to a motion correction algorithm. Existing techniques to track patient motion fall into one of two categories: 1) image-derived approaches and 2) external motion tracking (EMT). Typical EMT requires patients to have markers in a known pattern on a rigid too attached to their head, which are then tracked by expensive and bulky motion tracking camera systems or stereo cameras. This has made marker-based EMT unattractive for routine clinical application. Our main contributions are the development of a marker-less motion tracking system that uses lowcost, small depth-sensing cameras which can be installed in the bore of the imaging system. Our motion tracking system does not require anything to be attached to the patient and can track the rigid transformation (6-degrees of freedom) of the patient's head at a rate 60 Hz. We show that our method can not only be used in with Multi-frame Acquisition (MAF) PET motion correction, but precise timing can be employed to determine only the necessary frames needed for correction. This can speeds up reconstruction by eliminating the unnecessary subdivision of frames.

  3. Current status and future challenges of brain imaging with (18)F-DOPA PET for movement disorders.

    PubMed

    Calabria, Ferdinando Franco; Calabria, Eros; Gangemi, Vincenzo; Cascini, Giuseppe Lucio

    2016-01-01

    Parkinson's disease (PD) is a neurodegenerative disorder (ND) due to progressive loss of dopaminergic neurons in the basal ganglia. The correct differential diagnosis of this disease with parkinsonian syndromes (PS) or with essential tremor (ET) is a diagnostic dilemma, considering that only PD is responsive to treatment with levodopa. Traditional imaging fails to diagnose PD because morphological alterations in the brain are usually detectable only at advanced stages. Single photon emission tomography (SPET) with cocaine analogues has recently been used in the early detection of PD. The fluoro-18-deoxyphenyl-alanine ((18)F-DOPA) is a positron emission tomography (PET) tracer with selective in vivo affinity to the basal ganglia, due to the specific metabolism of substantia nigra. We assessed the effective use of (18)F-DOPA PET in brain imaging in order to describe the function of presynaptic disorders of PD, PS, ET and other movement disorders compared to SPET imaging and also discussed novel radiopharmaceuticals. The role of magnetic resonance imaging (MRI) was also discussed. (18)F-DOPA PET imaging is still the best diagnostic tool for the diagnosis of PD and other movement disorders. Fluorine-18-FDG PET can play a role in the differential diagnosis between PD and other PS. The hybrid (18)F-DOPA PET/MRI seems to be able to play an important additional role in early diagnosis of the above syndromes.

  4. MRI-based elastic-mapping method for inter-subject comparison of brain FDG-PET images

    SciTech Connect

    Yang, J.; Huang, S.C.; Lin, K.P.; Small, G.; Phelps, M.E.

    1996-12-31

    Inter-subject anatomic differences prohibits direct image-wise statistical evaluation of brain FDG-PET images of Alzheimer`s disease (AD) patients. In this study, we propose a MRI-based elastic-mapping method which enables image-wise evaluation. The method involves intra-subject MR-PET registration, 3-D elastic mapping of two set of MR images, and elastically transforming the co-registered PET images. The MR-PET registration used simulated PET images, which were based on segmentation of MR images. In the 3-D elastic mapping stage, first a global linear scaling was applied to compensate for brain size difference, then a deformation field was obtained by minimizing the regional sum of squared difference between the two sets of MR images. Two groups (AD patient and normal control), each with three subjects, were included in the current study. After processing, images from all subjects have similar shapes. Averaging the images across all subjects (either within the individual group or for both groups) give images indistinguishable from original single subject FDG images (i.e. without much spatial resolution loss), except with lower image noise level. The method is expected to allow statistical image-wise analysis to be performed across different subjects.

  5. Validating novel tau PET tracer [F-18]-AV-1451 (T807) on postmortem brain tissue

    PubMed Central

    Marquie, Marta; Normandin, Marc D.; Vanderburg, Charles R.; Costantino, Isabel; Bien, Elizabeth A.; Rycyna, Lisa G.; Klunk, William E.; Mathis, Chester A.; Ikonomovic, Milos D.; Debnath, Manik L.; Vasdev, Neil; Dickerson, Bradford C.; Gomperts, Stephen N.; Growdon, John H.; Johnson, Keith A.; Frosch, Matthew P.; Hyman, Bradley T.; Gomez-Isla, Teresa

    2016-01-01

    Objective To examine region and substrate-specific autoradiographic and in vitro binding patterns of PET tracer [F-18]-AV-1451 (previously known as T807), tailored to allow in vivo detection of paired helical filament tau-containing lesions, and to determine whether there is off-target binding to other amyloid/non-amyloid proteins. Methods We applied [F-18]-AV-1451 phosphor screen autoradiography, [F-18]-AV-1451 nuclear emulsion autoradiography and [H-3]-AV-1451 in vitro binding assays to the study of postmortem samples from patients with a definite pathological diagnosis of Alzheimer’s disease, frontotemporal lobar degeneration-tau, frontotemporal lobar degeneration-TDP-43, progressive supranuclear palsy, corticobasal degeneration, dementia with Lewy bodies, multiple system atrophy, cerebral amyloid angiopathy and elderly controls free of pathology. Results Our data suggest that AV-1451 strongly binds to tau lesions primarily made of paired helical filaments in Alzheimer’s brains e.g. intra and extraneuronal tangles and dystrophic neurites, but does not seem to bind to a significant extent to neuronal and glial inclusions mainly composed of straight tau filaments in non-Alzheimer tauopathy brains or to β-amyloid, α-synuclein or TDP-43-containing lesions. AV-1451 off-target binding to neuromelanin- and melanin-containing cells and, to a lesser extent, to brain hemorrhagic lesions was identified. Interpretation Our data suggest that AV-1451 holds promise as surrogate marker for the detection of brain tau pathology in the form of tangles and paired helical filament-tau-containing neurites in Alzheimer’s brains but also point to its relatively lower affinity for lesions primarily made of straight tau filaments in non-Alzheimer tauopathy cases and to the existence of some AV-1451 off-target binding. These findings provide important insights for interpreting in vivo patterns of [F-18]-AV-1451 retention. PMID:26344059

  6. Optimization of PET activation studies based on the SNR measured in the 3-D Hoffman brain phantom.

    PubMed

    Li, H H; Votaw, J R

    1998-08-01

    This work investigates the noise properties of O-15 water PET images in an attempt to increase the sensitivity of activation studies. A method for computing the amount of noise within a region of interest (ROI) from the uncertainty in the raw data was implemented for three-dimensional (3-D) positron emission tomography (PET). The method was used to study the signal-to-noise ratio (SNR) of regions-of-interest (ROI's) inside a 3-D Hoffman brain phantom. Saturation occurs at an activity concentration of 2.2 mCi/l which corresponds to a 75-mCi O-15 water injection into a normal person of average weight. This establishes the upper limit for injections for human brain studies using 3-D PET on the Siemens ECAT 921 EXACT scanner. Data from human brain activation studies on four normal volunteers using two-dimensional (2-D) PET were analyzed. The biological variation was found to be 5% in 1-ml ROI's. The variance for a complete activation study was calculated, for a variety of protocols, by combining the Poisson noise propagated from the raw data in the phantom experiments with the biological variation. A protocol that is predicted to maximize the SNR in dual-condition activation experiments while remaining below the radiation safety limit is: ten scans with 45 mCi per injection. The data should not be corrected for random or scatter events since they do not help in the identification of activation sites while they do add noise to the image. Due to the lower noise level of 3-D PET, the threshold for detecting a true change in activity concentration is 10%-20% lower than 2-D PET. Because of this, a 3-D activation experiment using the Siemens 921 scanner requires fewer subjects for equal statistical power.

  7. [(18)F]FDG-PET Combined with MRI Elucidates the Pathophysiology of Traumatic Brain Injury in Rats.

    PubMed

    Brabazon, Fiona; Wilson, Colin M; Shukla, Dinesh K; Mathur, Sanjeev; Jaiswal, Shalini; Bermudez, Sara; Byrnes, Kimberly R; Selwyn, Reed

    2017-03-01

    Non-invasive measurements of brain metabolism using (18)F-fluorodeoxyglucose (FDG) with positron emission tomography (PET) may provide important information about injury severity following traumatic brain injury (TBI). There is growing interest in the potential of combining functional PET imaging with anatomical and functional magnetic resonance imaging (MRI). This study aimed to investigate the effectiveness of combining clinically available FDG-PET with T2 and diffusion MR imaging, with a particular focus on inflammation and the influence of glial alterations after injury. Adult male Sprague Dawley rats underwent a moderate controlled cortical impact (CCI) injury followed by FDG-PET, MRI, and histological evaluation. FDG uptake showed significant alterations in the corpus callosum, hippocampus, and amygdala after TBI, demonstrating that a relatively "focal" CCI injury can result in global alterations. Analysis of MRI T2 intensity and apparent diffusion coefficient (ADC) also showed significant alterations in these regions to include cytotoxic and vasogenic edema. Histology showed increased glial activation in the corpus callosum and hippocampus that was associated with increased FDG uptake at sub-acute time-points. Glial activation was not detected in the amygdala but neuronal damage was evident, as the amygdala was the only region to show a reduction in both FDG uptake and ADC at sub-acute time-points. Overall, FDG-PET detected glial activation but was confounded by the presence of cell damage, whereas MRI consistently detected cell damage but was confounded by glial activation. These results demonstrate that FDG-PET and MRI can be used together to improve our understanding of the complex alterations in the brain after TBI.

  8. Parkinson's disease-related perfusion and glucose metabolic brain patterns identified with PCASL-MRI and FDG-PET imaging.

    PubMed

    Teune, Laura K; Renken, Remco J; de Jong, Bauke M; Willemsen, Antoon T; van Osch, Matthias J; Roerdink, Jos B T M; Dierckx, Rudi A; Leenders, Klaus L

    2014-01-01

    Under normal conditions, the spatial distribution of resting cerebral blood flow and cerebral metabolic rate of glucose are closely related. A relatively new magnetic resonance (MR) technique, pseudo-continuous arterial spin labeling (PCASL), can be used to measure regional brain perfusion. We identified a Parkinson's disease (PD)-related perfusion and metabolic covariance pattern in the same patients using PCASL and FDG-PET imaging and assessed (dis)similarities in the disease-related pattern between perfusion and metabolism in PD patients. Nineteen PD patients and seventeen healthy controls underwent [(18)F]-fluorodeoxyglucose positron emission tomography (FDG-PET) imaging. Of 14 PD patients and all healthy controls PCASL-MRI could be obtained. Data were analyzed using scaled subprofile model/principal component analysis (SSM/PCA). Unique Parkinson's disease-related perfusion and metabolic covariance patterns were identified using PCASL and FDG-PET in the same patients. The PD-related metabolic covariance brain pattern is in high accordance with previously reports. Also our disease-related perfusion pattern is comparable to the earlier described perfusion pattern. The most marked difference between our perfusion and metabolic patterns is the larger perfusion decrease in cortical regions including the insula. We identified PD-related perfusion and metabolic brain patterns using PCASL and FDG-PET in the same patients which were comparable with results of existing research. In this respect, PCASL appears to be a promising addition in the early diagnosis of individual parkinsonian patients.

  9. Parkinson's disease-related perfusion and glucose metabolic brain patterns identified with PCASL-MRI and FDG-PET imaging

    PubMed Central

    Teune, Laura K.; Renken, Remco J.; de Jong, Bauke M.; Willemsen, Antoon T.; van Osch, Matthias J.; Roerdink, Jos B.T.M.; Dierckx, Rudi A.; Leenders, Klaus L.

    2014-01-01

    Introduction Under normal conditions, the spatial distribution of resting cerebral blood flow and cerebral metabolic rate of glucose are closely related. A relatively new magnetic resonance (MR) technique, pseudo-continuous arterial spin labeling (PCASL), can be used to measure regional brain perfusion. We identified a Parkinson's disease (PD)-related perfusion and metabolic covariance pattern in the same patients using PCASL and FDG-PET imaging and assessed (dis)similarities in the disease-related pattern between perfusion and metabolism in PD patients. Methods Nineteen PD patients and seventeen healthy controls underwent [18F]-fluorodeoxyglucose positron emission tomography (FDG-PET) imaging. Of 14 PD patients and all healthy controls PCASL-MRI could be obtained. Data were analyzed using scaled subprofile model/principal component analysis (SSM/PCA). Results Unique Parkinson's disease-related perfusion and metabolic covariance patterns were identified using PCASL and FDG-PET in the same patients. The PD-related metabolic covariance brain pattern is in high accordance with previously reports. Also our disease-related perfusion pattern is comparable to the earlier described perfusion pattern. The most marked difference between our perfusion and metabolic patterns is the larger perfusion decrease in cortical regions including the insula. Conclusion We identified PD-related perfusion and metabolic brain patterns using PCASL and FDG-PET in the same patients which were comparable with results of existing research. In this respect, PCASL appears to be a promising addition in the early diagnosis of individual parkinsonian patients. PMID:25068113

  10. 18F-FDG PET/CT Brain Imaging on a Patient With Paraneoplastic Opsoclonus-Myoclonus Syndrome Arising out of a Mature Cystic Teratoma.

    PubMed

    Na, Chang Ju; Jeong, Young Jin; Lim, Seok Tae; Sohn, Myung-Hee; Jeong, Hwan-Jeong

    2016-02-01

    Opsoclonus-myoclonus syndrome (OMS) is an involuntary multidirectional eye movement accompanied by myoclonic jerks and a subtype of paraneoplastic neurological syndromes. Clinical features of OMS include opsoclonus with myoclonic jerks and cerebellar ataxia. Although there have been a few studies on brain FDG PET in paraneoplastic neurological syndrome associated with some kinds of malignancies such as lung and gastric cancer, brain FDG PET of patients with OMS caused by a mature cystic teratoma has not been reported. Here, we described a case of brain FDG PET/CT studies performed in a woman with OMS provoked from a mature cystic teratoma.

  11. NEMA and clinical evaluation of a novel brain PET-CT scanner

    PubMed Central

    Grogg, Kira S.; Toole, Terrence; Ouyang, Jinsong; Zhu, Xuping; Normandin, Marc; Johnson, Keith; Alpert, Nathaniel M.; Fakhri, Georges El

    2016-01-01

    The aim of this study was to determine the performance of a novel mobile human brain/small animal PET-CT system, developed by Photo Diagnostic Systems Inc. The scanner has a 35.7-cm diameter bore and a 22-cm axial extent. The detector ring has 7 modules each with 3×4 cerium-doped lutetium yttrium orthosilicate crystal blocks, each consisting of 22×22 outer layer and 21×21 inner layer crystals, each layer 1 cm thick. Light is collected by 12×12 SiPMs. The integrated CT can be used for attenuation correction and anatomical localization. The scanner was designed as a low-cost device that nevertheless produces high-quality PET images with the unique capability of battery-powered propulsion, enabling use in many settings. Methods Spatial resolution, sensitivity and noise-equivalent count rate (NECR) were measured based on the National Electrical Manufacturers Association NU2-2012 procedures. Reconstruction was done with tight energy and timing cuts: 400-650 keV and 7ns, and loose cuts: 350-700 keV and 10ns. Additional image quality measurements were made from phantoms, human, and animal studies. Performance was compared to a reference scanner (ECAT Exact HR+) with comparable imaging properties. Results The full-width half-max transverse resolution at 1 cm (10 cm) radius is 3.2 mm (5.2 mm radial, 3.1 mm tangential) and the axial resolution is 3.5 mm (4.0 mm). For tight (loose) cuts, a sensitivity of 7.5 (11.7) kcps/MBq at the center increases to 8.8 (13.9) kcps/MBq at a 10 cm radial offset. The maximum NECR of 19.5 (22.7) kcps was achieved for an activity concentration of 2.9 kBq/ml. Contrast recovery for 4:1 hot cylinder to warm background was 76% for the 25 mm diameter cylinder, but decreased with decreasing cylinder size. The quantitation agrees within 2% of the known activity distribution and concentration. Brain phantom and human scans have shown agreement in SUV values and image quality with the HR+. Conclusion We have characterized the performance of the NeuroPET

  12. National Electrical Manufacturers Association and Clinical Evaluation of a Novel Brain PET/CT Scanner.

    PubMed

    Grogg, Kira S; Toole, Terrence; Ouyang, Jinsong; Zhu, Xuping; Normandin, Marc D; Li, Quanzheng; Johnson, Keith; Alpert, Nathaniel M; El Fakhri, Georges

    2016-04-01

    The aim of this study was to determine the performance of a novel mobile human brain/small-animal PET/CT system. The scanner has a 35.7-cm-diameter bore and a 22-cm axial extent. The detector ring has 7 modules each with 3 × 4 cerium-doped lutetium yttrium orthosilicate crystal blocks, each consisting of 22 × 22 outer-layer and 21 × 21 inner-layer crystals, each layer 1-cm thick. Light is collected by 12 × 12 silicon photomultipliers. The integrated CT can be used for attenuation correction and anatomic localization. The scanner was designed as a low-cost device that nevertheless produces high-quality PET images with the unique capability of battery-powered propulsion, enabling use in many settings. Spatial resolution, sensitivity, and noise-equivalent counting rate were measured based on the National Electrical Manufacturers Association NU2-2012 procedures. Reconstruction was done with tight energy and timing cuts-400-650 keV and 7 ns-and loose cuts-350-700 keV and 10 ns. Additional image quality measurements were made from phantom, human, and animal studies. Performance was compared with a reference scanner with comparable imaging properties. The full width at half maximum transverse resolution at a 1-cm (10-cm) radius was 3.2 mm (5.2-mm radial, 3.1-mm tangential), and the axial resolution was 3.5 mm (4.0 mm). A sensitivity of 7.5 and 11.7 kcps/MBq at the center for tight and loose cuts, respectively, increased to 8.8 and 13.9 kcps/MBq, respectively, at a 10-cm radial offset. The maximum noise-equivalent counting rate of 19.5 and 22.7 kcps for tight and loose cuts, respectively, was achieved for an activity concentration of 2.9 kBq/mL. Contrast recovery for 4:1 hot cylinder to warm background was 76% for the 25-mm-diameter cylinder but decreased with decreasing cylinder size. The quantitation agreed within 2% of the known activity distribution and concentration. Brain phantom and human scans have shown agreement in SUVs and image quality with the reference

  13. Epileptic Activity Increases Cerebral Amino Acid Transport Assessed by 18F-Fluoroethyl-l-Tyrosine Amino Acid PET: A Potential Brain Tumor Mimic.

    PubMed

    Hutterer, Markus; Ebner, Yvonne; Riemenschneider, Markus J; Willuweit, Antje; McCoy, Mark; Egger, Barbara; Schröder, Michael; Wendl, Christina; Hellwig, Dirk; Grosse, Jirka; Menhart, Karin; Proescholdt, Martin; Fritsch, Brita; Urbach, Horst; Stockhammer, Guenther; Roelcke, Ulrich; Galldiks, Norbert; Meyer, Philipp T; Langen, Karl-Josef; Hau, Peter; Trinka, Eugen

    2017-01-01

    O-(2-(18)F-fluoroethyl)-l-tyrosine ((18)F-FET) PET is a well-established method increasingly used for diagnosis, treatment planning, and monitoring in gliomas. Epileptic activity, frequently occurring in glioma patients, can influence MRI findings. Whether seizures also affect (18)F-FET PET imaging is currently unknown. The aim of this retrospective analysis was to investigate the brain amino acid metabolism during epileptic seizures by (18)F-FET PET and to elucidate the pathophysiologic background.

  14. Evaluation of regional differences of tracer appearance time in cerebral tissues using (/sup 15/O) water and dynamic positron emission tomography

    SciTech Connect

    Iida, H.; Higano, S.; Tomura, N.; Shishido, F.; Kanno, I.; Miura, S.; Murakami, M.; Takahashi, K.; Sasaki, H.; Uemura, K.

    1988-04-01

    The tracer appearance time relative to the radial artery-sampling site has been evaluated in six brain locations in five human subjects using dynamic positron emission tomography (PET) following the bolus injection of H/sub 2/(/sup 15/)O. There was a maximum difference of +/- 2 s from the average in each location. To globally adjust the timing difference between the measured arterial curve and the PET scan, a correction method was developed based on a nonlinear least-squares fitting procedure. This new technique determined the global time delay with an accuracy of +/- 0.5 s. On the other hand, the linear backward extrapolation method resulted in a systematic error of 4 s.

  15. Impact of benzodiazepines on brain FDG-PET quantification after single-dose and chronic administration in rats.

    PubMed

    Silva-Rodríguez, Jesús; García-Varela, Lara; López-Arias, Esteban; Domínguez-Prado, Inés; Cortés, Julia; Pardo-Montero, Juan; Fernández-Ferreiro, Anxo; Ruibal, Álvaro; Sobrino, Tomás; Aguiar, Pablo

    2016-12-01

    Current guidelines for brain PET imaging advice against the injection of diazepam prior to brain FDG-PET examination in order to avoid possible interactions of benzodiazepines with the radiotracer uptake. Nevertheless, many patients undergoing PET studies are likely to be under chronic treatment with benzodiazepines, for example due to the use of different medications such as sleeping pills. Animal studies may provide an extensive and accurate estimation of the effect of benzodiazepines on brain metabolism in a well-defined and controlled framework. This study aims at evaluating the impact of benzodiazepines on brain FDG uptake after single-dose administration and chronic treatment in rats. Twelve Sprague-Dawley healthy rats were randomly divided into two groups, one treated with diazepam and the other used as control group. Both groups underwent PET/CT examinations after single-dose and chronic administration of diazepam (treated) or saline (controls) during twenty-eight days. Different atlas-based quantification methods were used to explore differences on the total uptake and uptake patterns of FDG between both groups. Our analysis revealed a significant reduction of global FDG uptake after acute (-16.2%) and chronic (-23.2%) administration of diazepam. Moreover, a strong trend pointing to differences between acute and chronic administrations (p<0.08) was also observed. Uptake levels returned to normal after interrupting the administration of diazepam. On the other hand, patterns of FDG uptake were not affected by the administration of diazepam. The administration of diazepam causes a progressive decrease of the FDG global uptake in the rat brain, but it does not change local patterns within the brain. Under these conditions, visual assessment and quantification methods based on regional differences such as asymmetry indexes or SPM statistical analysis would still be valid when administrating this medication. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Open-field mouse brain PET: design optimisation and detector characterisation

    NASA Astrophysics Data System (ADS)

    Kyme, Andre Z.; Judenhofer, Martin S.; Gong, Kuang; Bec, Julien; Selfridge, Aaron; Du, Junwei; Qi, Jinyi; Cherry, Simon R.; Meikle, Steven R.

    2017-08-01

    ‘Open-field’ PET, in which an animal is free to move within an enclosed space during imaging, is a very promising advance for neuroscientific research. It provides a key advantage over conventional imaging under anesthesia by enabling functional changes in the brain to be correlated with an animal’s behavioural response to environmental or pharmacologic stimuli. Previously we have demonstrated the feasibility of open-field imaging of rats using motion compensation techniques applied to a commercially available PET scanner. However, this approach of ‘retro-fitting’ motion compensation techniques to an existing system is limited by the inherent geometric and performance constraints of the system. The goal of this project is to develop a purpose-built PET scanner with geometry, motion tracking and imaging performance tailored and optimised for open-field imaging of the mouse brain. The design concept is a rail-based sliding tomograph which moves according to the animal’s motion. Our specific aim in this work was to evaluate candidate scanner designs and characterise the performance of a depth-of-interaction detector module for the open-field system. We performed Monte Carlo simulations to estimate and compare the sensitivity and spatial resolution performance of four scanner geometries: a ring, parallel plate, and two box variants. Each system was based on a detector block consisting of a 23  ×  23 array of 0.785  ×  0.785  ×  20 mm3 LSO crystals (overall dim. 19.6  ×  19.6  ×  20 mm). We found that a DoI resolution capability of 3 mm was necessary to achieve approximately uniform sub-millimetre spatial resolution throughout the FoV for all scanners except the parallel-plate geometry. With this DoI performance, the sensitivity advantage afforded by the box geometry with overlapping panels (16% peak absolute sensitivity, a 36% improvement over the ring design) suggests this unconventional design is best

  17. Open-field mouse brain PET: design optimisation and detector characterisation.

    PubMed

    Kyme, Andre Z; Judenhofer, Martin S; Gong, Kuang; Bec, Julien; Selfridge, Aaron; Du, Junwei; Qi, Jinyi; Cherry, Simon R; Meikle, Steven R

    2017-07-13

    'Open-field' PET, in which an animal is free to move within an enclosed space during imaging, is a very promising advance for neuroscientific research. It provides a key advantage over conventional imaging under anesthesia by enabling functional changes in the brain to be correlated with an animal's behavioural response to environmental or pharmacologic stimuli. Previously we have demonstrated the feasibility of open-field imaging of rats using motion compensation techniques applied to a commercially available PET scanner. However, this approach of 'retro-fitting' motion compensation techniques to an existing system is limited by the inherent geometric and performance constraints of the system. The goal of this project is to develop a purpose-built PET scanner with geometry, motion tracking and imaging performance tailored and optimised for open-field imaging of the mouse brain. The design concept is a rail-based sliding tomograph which moves according to the animal's motion. Our specific aim in this work was to evaluate candidate scanner designs and characterise the performance of a depth-of-interaction detector module for the open-field system. We performed Monte Carlo simulations to estimate and compare the sensitivity and spatial resolution performance of four scanner geometries: a ring, parallel plate, and two box variants. Each system was based on a detector block consisting of a 23  ×  23 array of 0.785  ×  0.785  ×  20 mm(3) LSO crystals (overall dim. 19.6  ×  19.6  ×  20 mm). We found that a DoI resolution capability of 3 mm was necessary to achieve approximately uniform sub-millimetre spatial resolution throughout the FoV for all scanners except the parallel-plate geometry. With this DoI performance, the sensitivity advantage afforded by the box geometry with overlapping panels (16% peak absolute sensitivity, a 36% improvement over the ring design) suggests this unconventional design is best suited for

  18. Functional brain mapping of actual car-driving using [18F]FDG-PET.

    PubMed

    Jeong, Myeonggi; Tashiro, Manabu; Singh, Laxsmi N; Yamaguchi, Keiichiro; Horikawa, Etsuo; Miyake, Masayasu; Watanuki, Shouichi; Iwata, Ren; Fukuda, Hiroshi; Takahashi, Yasuo; Itoh, Masatoshi

    2006-11-01

    This study aims at identifying the brain activation during actual car-driving on the road, and at comparing the results to those of previous studies on simulated car-driving. Thirty normal volunteers, aged 20 to 56 years, were divided into three subgroups, active driving, passive driving and control groups, for examination by positron emission tomography (PET) and [18F]2-deoxy-2-fluoro-D-glucose (FDG). The active driving subjects (n = 10) drove for 30 minutes on quiet normal roads with a few traffic signals. The passive driving subjects (n = 10) participated as passengers on the front seat. The control subjects (n = 10) remained seated in a lit room with their eyes open. Voxel-based t-statistics were applied using SPM2 to search brain activation among the subgroups mentioned above. Significant brain activation was detected during active driving in the primary and secondary visual cortices, primary sensorimotor areas, premotor area, parietal association area, cingulate gyrus, the parahippocampal gyrus as well as in thalamus and cerebellum. The passive driving manifested a similar-looking activation pattern, lacking activations in the premotor area, cingulate and parahippocampal gyri and thalamus. Direct comparison of the active and passive driving conditions revealed activation in the cerebellum. The result of actual driving looked similar to that of simulated driving, suggesting that visual perception and visuomotor coordination were the main brain functions while driving. In terms of attention and autonomic arousal, however, it seems there was a significant difference between simulated and actual driving possibly due to risk of accidents. Autonomic and emotional aspects of driving should be studied using an actual driving study-design.

  19. 55Cobalt (Co) as a PET-tracer in stroke, compared with blood flow, oxygen metabolism, blood volume and gadolinium-MRI.

    PubMed

    Stevens, H; Jansen, H M; De Reuck, J; Lemmerling, M; Strijckmans, K; Goethals, P; Lemahieu, I; de Jong, B M; Willemsen, A T; Korf, J

    1999-12-01

    Several studies have shown the feasibility of divalent cobalt (Co)-isotopes (55Co and 57Co) in imaging of neuronal damage in stroke, multiple sclerosis, cerebral tumors and traumatic brain injury. Little is known how regional Co uptake relates to other pathophysiological changes after stroke. Therefore, we compared 55Co-PET with functional parameters such as regional cerebral blood flow (rCBF) using C(15)O(2), regional oxygen metabolism (rCMRO(2)) using 15O(2), regional cerebral blood volume (rCBV) and post-gadolinium (Gd) T(1)w-MRI to assess the permeability of the blood-brain-barrier (BBB). Sixteen patients (10 female; six male) aged 43 to 84 (mean 69) years with first ever stroke, as shown by CT or MRI, were examined with 55Co-PET and C(15)O(2)-, 15O(2)- and C(15)O-PET in one single session, in a period varying from 0 to 30 days after stroke-onset. Regions of infarction on C(15)O(2)- and 15O(2)-PET (defined by rCMRO(2)<65% or rCBF<45% of the contralateral value) were subsequently superimposed on the 55Co-PET scan. Clinical status was established using the Orgogozo stroke scale, which was assessed both at day 1 and at discharge (at least 6 weeks after day 1). Accumulation of 55Co was seen in eight out of 16 patients, occurring in areas showing a diminished oxygen metabolism, was only partially related to blood flow, and was located mainly outside the extent of the infarction or luxury perfusion as seen on post-Gd T(1)w-MRI. Statistical analysis showed a negative correlation between the Orgogozo score at discharge and the uptake of radioactive cobalt.

  20. Metabolic imaging of deep brain stimulation in anorexia nervosa: a 18F-FDG PET/CT study.

    PubMed

    Zhang, Hui-Wei; Li, Dian-You; Zhao, Jun; Guan, Yi-Hui; Sun, Bo-Min; Zuo, Chuan-Tao

    2013-12-01

    Anorexia nervosa (AN), a disorder of unknown etiology, has the highest mortality rate of any psychiatric disorder. Drawing the brain metabolic pattern of AN may help to target the core biological and psychological features of the disorder and to perfect the diagnosis and recovery criteria. In this study, we used 18F-FDG PET to show brain metabolic network for AN. Glucose metabolism in 6 AN patients and 12 age-matched healthy controls was studied using 18F-FDG PET. SPM2 was used to compare brain metabolism in AN patients with that in healthy controls. Four of 6 AN patients took deep brain stimulation (DBS) targeted in nucleus accumbens (NAcc). About 3 to 6 months after the surgery, the 4 AN patients took another 18F-FDG PET scan to assess the change in brain glucose metabolism. The SPM (statistical parametric mapping ) analysis showed hypermetabolism in the frontal lobe (bilateral, BA10, BA11, BA47), the limbic lobe (bilateral, hippocampus, and amygdala), lentiform nucleus (bilateral), left insula (BA13), and left subcallosal gyrus (BA25). It also showed hypometabolism in the parietal lobe (bilateral, BA7, BA40). The hypermetabolism in frontal lobe, hippocampus, and lentiform nucleus decreased after NAcc-DBS. The changes in brain glucose metabolism illustrated the brain metabolic pattern in AN patients. Furthermore, the pattern can be modulated by NAcc-DBS, which confirmed specificity of the pattern. The regions with altered metabolism could interconnect to form a network and integrate information related to appetite. Our study may provide information for targeting the potential candidate brain regions for understanding the pathophysiology of AN and assessing the effects of existing and future treatment approaches.

  1. Factors affecting bilateral temporal lobe hypometabolism on 18F-FDG PET brain scan in unilateral medial temporal lobe epilepsy.

    PubMed

    Tepmongkol, Supatporn; Srikijvilaikul, Teeradej; Vasavid, Pataramon

    2013-11-01

    Bilateral temporal lobe hypometabolism (BTH) on (18)F-FDG PET brain scan is frequently seen in unilateral medial temporal lobe epilepsy (mTLE). This study aimed to identify the factors that influence BTH in patients with mTLE in order to minimize the significant factor(s) prior to performing a FDG-PET brain scan. Forty patients with unilateral mTLE who underwent (18)F-FDG PET scan for presurgical epilepsy workup were included. Bilateral temporal lobe hypometabolism of the anterior and medial parts of the temporal lobe was identified by a semiquantitative visual scale. Lateralization of TLE was identified by either intracranial EEG (22/40 cases) and/or improvement of seizure 2 years after temporal lobectomy (37/40 cases). The factors analyzed included basic demographic characteristics (age, sex, occupation, years of education, and handedness), history related to seizure (age at epilepsy onset and epilepsy duration, history of febrile seizure and head injury, frequency of seizure with impaired cognition in the last 3 months, presence of secondarily generalized tonic-clonic seizure, automatism side, presence of postictal confusion, and side of MRI temporal abnormality), information during video-EEG monitoring (clinical lateralization, interictal scalp EEG lateralization (interictal epileptiform discharge), and ictal scalp EEG lateralization), and information during the FDG-PET study (duration from the last seizure (≤2 days or >2 days), last seizure type, and the presence of slow waves or sharp waves during the FDG uptake period). Significant factors related to BTH were analyzed using multivariate analysis. Only the ≤2-day duration from the last seizure to the PET scan shows a significant effect (p=0.021) on BTH finding with 15 times greater incidence compared to a duration >2 days. Bilateral temporal lobe hypometabolism, which causes conflict in lateralizing the epileptogenic zone in temporal lobe epilepsy, can be avoided by performing PET scan more than 2 days

  2. Unexpected detection of melanoma brain metastasis by PET with iodine-124 betaCIT.

    PubMed

    Cascini, Giuseppe Lucio; Ciarmiello, Andrea; Labate, Angelo; Tamburrini, Stefania; Quattrone, Aldo

    2009-10-01

    To study the potential impact of iodine-124-beta-carbomethoxy-3beta(4-iodophenyl)tropane (I-124 betaCIT) in Parkinson disease, a I-124 betaCIT-PET scan was performed in 30-year-old man with suspected early Parkinson disease. The scan showed normal striatum uptake together with a focal spot in the left parietal cortex. The subsequent magnetic resonance imaging of the brain revealed a corresponding nodular lesion, presumably representing a metastasis. After clinical and diagnostic evaluation, a malignant metastatic melanoma was discovered. betaCIT is a cocaine derivative with a high affinity for dopamine and serotonin transporters mainly used to image the density of the dopamine reuptake transporter. In fact the role of I-123 betaCIT is typically represented by Parkinsonian syndromes of uncertain classification. The iodine-124 betaCIT uptake is a marker of dopamine transporters density, and the presence of focal uptake corresponding to a lesion on magnetic resonance images suggests a specific binding in this case of melanoma brain metastasis.

  3. Feasibility of simultaneous whole-brain imaging on an integrated PET-MRI system using an enhanced 2-point Dixon attenuation correction method

    PubMed Central

    Anazodo, Udunna C.; Thiessen, Jonathan D.; Ssali, Tracy; Mandel, Jonathan; Günther, Matthias; Butler, John; Pavlosky, William; Prato, Frank S.; Thompson, R. Terry; St. Lawrence, Keith S.

    2015-01-01

    Purpose: To evaluate a potential approach for improved attenuation correction (AC) of PET in simultaneous PET and MRI brain imaging, a straightforward approach that adds bone information missing on Dixon AC was explored. Methods: Bone information derived from individual T1-weighted MRI data using segmentation tools in SPM8, were added to the standard Dixon AC map. Percent relative difference between PET reconstructed with Dixon+bone and with Dixon AC maps were compared across brain regions of 13 oncology patients. The clinical potential of the improved Dixon AC was investigated by comparing relative perfusion (rCBF) measured with arterial spin labeling to relative glucose uptake (rPETdxbone) measured simultaneously with 18F-flurodexoyglucose in several regions across the brain. Results: A gradual increase in PET signal from center to the edge of the brain was observed in PET reconstructed with Dixon+bone. A 5–20% reduction in regional PET signals were observed in data corrected with standard Dixon AC maps. These regional underestimations of PET were either reduced or removed when Dixon+bone AC was applied. The mean relative correlation coefficient between rCBF and rPETdxbone was r = 0.53 (p < 0.001). Marked regional variations in rCBF-to-rPET correlation were observed, with the highest associations in the caudate and cingulate and the lowest in limbic structures. All findings were well matched to observations from previous studies conducted with PET data reconstructed with computed tomography derived AC maps. Conclusion: Adding bone information derived from T1-weighted MRI to Dixon AC maps can improve underestimation of PET activity in hybrid PET-MRI neuroimaging. PMID:25601825

  4. [(11)C]AZ10419096 - a full antagonist PET radioligand for imaging brain 5-HT1B receptors.

    PubMed

    Lindberg, Anton; Nag, Sangram; Schou, Magnus; Takano, Akihiro; Matsumoto, Junya; Amini, Nahid; Elmore, Charles S; Farde, Lars; Pike, Victor W; Halldin, Christer

    2017-07-21

    The serotonergic system is widely present in all regions of the central nervous system (CNS) and plays a key modulatory role in many of its functions. Positron emission tomography (PET) is used to study several serotonin receptors in CNS in vivo. The G-protein coupled receptor 5-HT1B is mostly present in the occipital cortex and in midbrain and is linked to several psychiatric disorders. There is evidence that agonist PET radioligands for neuroreceptors are more sensitive to endogenous neurotransmitters than antagonists. Our previously developed 5-HT1B receptor PET radioligand, [(11)C]AZ10419369, is now considered a partial agonist. In this work we are aiming to develop a full antagonist PET radioligand for imaging brain 5-HT1B receptors, and evaluate its sensitivity to increased endogenous serotonin concentration. [(11)C]AZ10419096 was synthesized by rapid methylation of the prepared corresponding N-desmethyl precursor with [(11)C]methyl triflate. Five PET measurements were performed in cynomolgus monkeys, consisting of two at baseline, one after treatment of a monkey with a 5-HT1B antagonist, AR-A000002, and two in which fenfluramine was administered during scanning to induce endogenous serotonin release. [(11)C]AZ10419096 was synthesized in high yield and purity within 30 min, including purification, formulation and sterile filtration. The baseline PET measurements demonstrated [(11)C]AZ10419096 to have favorable radioligand characteristics, including high specific binding in brain regions that have high 5-HT1B density, such as occipital cortex and globus pallidus, as well as subsequent rapid elimination from brain and a minor abundance of lipophilic radiometabolites in plasma. AR-A00002 completely blocked radioligand receptor-specific binding. Fenfluramine produced a distinct displacement of radioligand consistent with an expected increase of synaptic endogenous serotonin concentration. [(11)C]AZ10419096, a full 5-HT1B antagonist PET radioligand, demonstrates

  5. Markerless rat head motion tracking using structured light for brain PET imaging of unrestrained awake small animals

    NASA Astrophysics Data System (ADS)

    Miranda, Alan; Staelens, Steven; Stroobants, Sigrid; Verhaeghe, Jeroen

    2017-03-01

    Preclinical positron emission tomography (PET) imaging in small animals is generally performed under anesthesia to immobilize the animal during scanning. More recently, for rat brain PET studies, methods to perform scans of unrestrained awake rats are being developed in order to avoid the unwanted effects of anesthesia on the brain response. Here, we investigate the use of a projected structure stereo camera to track the motion of the rat head during the PET scan. The motion information is then used to correct the PET data. The stereo camera calculates a 3D point cloud representation of the scene and the tracking is performed by point cloud matching using the iterative closest point algorithm. The main advantage of the proposed motion tracking is that no intervention, e.g. for marker attachment, is needed. A manually moved microDerenzo phantom experiment and 3 awake rat [18F]FDG experiments were performed to evaluate the proposed tracking method. The tracking accuracy was 0.33 mm rms. After motion correction image reconstruction, the microDerenzo phantom was recovered albeit with some loss of resolution. The reconstructed FWHM of the 2.5 and 3 mm rods increased with 0.94 and 0.51 mm respectively in comparison with the motion-free case. In the rat experiments, the average tracking success rate was 64.7%. The correlation of relative brain regional [18F]FDG uptake between the anesthesia and awake scan reconstructions was increased from on average 0.291 (not significant) before correction to 0.909 (p  <  0.0001) after motion correction. Markerless motion tracking using structured light can be successfully used for tracking of the rat head for motion correction in awake rat PET scans.

  6. Minimally invasive input function for 2-18F-fluoro-A-85380 brain PET studies.

    PubMed

    Zanotti-Fregonara, Paolo; Maroy, Renaud; Peyronneau, Marie-Anne; Trebossen, Régine; Bottlaender, Michel

    2012-04-01

    Quantitative neuroreceptor positron emission tomography (PET) studies often require arterial cannulation to measure input function. While population-based input function (PBIF) would be a less invasive alternative, it has only rarely been used in conjunction with neuroreceptor PET tracers. The aims of this study were (1) to validate the use of PBIF for 2-(18)F-fluoro-A-85380, a tracer for nicotinic receptors; (2) to compare the accuracy of measures obtained via PBIF to those obtained via blood-scaled image-derived input function (IDIF) from carotid arteries; and (3) to explore the possibility of using venous instead of arterial samples for both PBIF and IDIF. Ten healthy volunteers underwent a dynamic 2-(18)F-fluoro-A-85380 brain PET scan with arterial and, in seven subjects, concurrent venous serial blood sampling. PBIF was obtained by averaging the normalized metabolite-corrected arterial input function and subsequently scaling each curve with individual blood samples. IDIF was obtained from the carotid arteries using a blood-scaling method. Estimated Logan distribution volume (V(T)) values were compared to the reference values obtained from arterial cannulation. For all subjects, PBIF curves scaled with arterial samples were similar in shape and magnitude to the reference arterial input function. The Logan V(T) ratio was 1.00 ± 0.05; all subjects had an estimation error <10%. IDIF gave slightly less accurate results (V(T) ratio 1.03 ± 0.07; eight of ten subjects had an error <10%). PBIF scaled with venous samples yielded inaccurate results (V(T) ratio 1.13 ± 0.13; only three of seven subjects had an error <10%). Due to arteriovenous differences at early time points, IDIF could not be calculated using venous samples. PBIF scaled with arterial samples accurately estimates Logan V(T) for 2-(18)F-fluoro-A-85380. Results obtained with PBIF were slightly better than those obtained with IDIF. Due to arteriovenous concentration differences, venous samples cannot be

  7. Neurobehavioural dysfunction following mild traumatic brain injury in childhood: a case report with positive findings on positron emission tomography (PET).

    PubMed

    Roberts, M A; Manshadi, F F; Bushnell, D L; Hines, M E

    1995-07-01

    The present case study describes the neurobehavioural, neurodiagnostic, and positron emission tomography (PET) scan findings in a child who sustained a whiplash-type injury in a motor vehicle accident. Although neck and back pain were reported immediately, neurobehavioural symptoms, such as staring spells, gradually increased in frequency over a 2-year period following the accident. At 4 years after the accident the patient's symptoms persisted, as reported by teachers and parents, and more extensive diagnostic work-up was initiated. Standard EEG was normal while two ambulatory EEGs were abnormal and interpreted as epileptiform. A PET scan showed evidence of marked hypometabolism in both temporal lobes. Neuropsychological findings were consistent with PET findings and reflected verbal and visual memory deficits in the context of high average intelligence. Treatment with carbamazepine, verapamil, and fluoxetine greatly improved the patient's symptoms. The present case illustrates an example of a poor outcome in a paediatric case of mild traumatic brain injury, the importance of PET in demonstrating definitive evidence of brain dysfunction, and the child's positive response to anticonvulsant medication.

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

    NASA Astrophysics Data System (ADS)

    Hu, Wei; Choi, Yong; Hong, Key Jo; Kang, Jihoon; Jung, Jin Ho; Huh, Youn Suk; Lim, Hyun Keong; Kim, Sang Su; Kim, Byung-Tae; Chung, Yonghyun

    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 (4×4 array, pixel size: 3 mm×3 mm) coupled 1:1 with LYSO scintillators (4×4 array, pixel size: 3 mm×3 mm×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 then transferred to a host computer for coincidence sorting and image reconstruction. In order to

  9. PET imaging of brain macrophages using the peripheral benzodiazepine receptor in a macaque model of neuroAIDS

    PubMed Central

    Venneti, Sriram; Lopresti, Brian J.; Wang, Guoji; Bissel, Stephanie J.; Mathis, Chester A.; Meltzer, Carolyn C.; Boada, Fernando; Capuano, Saverio; Kress, Geraldine J.; Davis, Denise K.; Ruszkiewicz, James; Reynolds, Ian J.; Murphey-Corb, Michael; Trichel, Anita M.; Wisniewski, Stephen R.; Wiley, Clayton A.

    2004-01-01

    HIV infection in humans and simian immunodeficiency virus (SIV) infection in macaques result in encephalitis in approximately one-quarter of infected individuals and is characterized by infiltration of the brain with infected and activated macrophages. 1-(2-chlorphenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinoline-carboxamide (PK11195) is a ligand specific for the peripheral benzodiazepine receptor abundant on macrophages and is expressed in low levels in the noninfected brain. We hypothesized that positron-emission tomography (PET) with the carbon-11–labeled, R-enantiomer form of PK11195 ([11C](R)-PK11195) could image brain macrophages and hence the development of encephalitis in vivo. [11C](R)-PK11195 binding was assessed in the brain using PET in 11 SIV infected macaques, six of which showed increased binding in vivo. Postmortem examination of the brain in these six macaques demonstrated encephalitis, while macaques that did not show an increase in [11C](R)-PK11195 binding did not develop SIV encephalitis. Brain tissue from SIV encephalitic macaques also showed increased [3H](R)-PK11195 binding compared with binding in nonencephalitic macaques. Increased PK11195 binding in vivo and in postmortem brain tissue correlated with abundance of macrophages but not astrocytes. Our results suggest that PET [11C](R)-PK11195 imaging can detect the presence of macrophages in SIV encephalitis in vivo and may be useful to predict the development of HIV encephalitis and in studies of the pathogenesis and treatment of HIV dementia. PMID:15057304

  10. Coregistered whole body magnetic resonance imaging-positron emission tomography (MRI-PET) versus PET-computed tomography plus brain MRI in staging resectable lung cancer: comparisons of clinical effectiveness in a randomized trial.

    PubMed

    Yi, Chin A; Lee, Kyung Soo; Lee, Ho Yun; Kim, Seonwoo; Kwon, O Jung; Kim, Hojoong; Choi, Joon Young; Kim, Byung-Tae; Hwang, Hye Sun; Shim, Young Mog

    2013-05-15

    The objective of this study was to assess whether coregistered whole brain (WB) magnetic resonance imaging-positron emission tomography (MRI-PET) would increase the number of correctly upstaged patients compared with WB PET-computed tomography (PET-CT) plus dedicated brain MRI in patients with nonsmall cell lung cancer (NSCLC). From January 2010 through November 2011, patients with NSCLC who had resectable disease based on conventional staging were assigned randomly either to coregistered MRI-PET or WB PET-CT plus brain MRI (ClinicalTrials.gov trial NCT01065415). The primary endpoint was correct upstaging (the identification of lesions with higher tumor, lymph node, or metastasis classification, verified with biopsy or other diagnostic test) to have the advantage of avoiding unnecessary thoracotomy, to determine appropriate treatment, and to accurately predict patient prognosis. The secondary endpoints were over staging and under staging compared with pathologic staging. Lung cancer was correctly upstaged in 37 of 143 patients (25.9%) in the MRI-PET group and in 26 of 120 patients (21.7%) in the PET-CT plus brain MRI group (4.2% difference; 95% confidence interval, -6.1% to 14.5%; P = .426). Lung cancer was over staged in 26 of 143 patients (18.2%) in the MRI-PET group and in 7 of 120 patients (5.8%) in the PET-CT plus brain MRI group (12.4% difference; 95% confidence interval, 4.8%-20%; P = .003), whereas lung cancer was under staged in 18 of 143 patients (12.6%) and in 28 of 120 patients (23.3%), respectively (-10.7% difference; 95% confidence interval, -20.1% to -1.4%; P = .022). Although both staging tools allowed greater than 20% correct upstaging compared with conventional staging methods, coregistered MRI-PET did not appear to help identify significantly more correctly upstaged patients than PET-CT plus brain MRI in patients with NSCLC. Copyright © 2013 American Cancer Society.

  11. Can brain thallium 201 SPECT substitute for F-18-FDG PET in detecting recurrent brain tumor in the presence of radiation necrosis; correlation with biopsy/surgery results

    SciTech Connect

    Antar, M.A.; Barnett, G.H.; McIntyre, W.J.

    1994-05-01

    F-18-FDG PET man has been largely successful in differentiating between radiation necrosis and recurrent brain tumors. Because of the expense and unavailability of PET scanners in most clinical centers, Tl-201 SPECT scan may offer an alternative. Therefore, we have evaluated both techniques in 18 patients (13 men and 5 women) whose ages range from 28 to 74 year old. Eleven patients had glioblastoma multiformi and 4 patients high grade astrocytoma and 3 patient meningiosarcoma. All patients received radiation therapy (5500-6000 Rad) and 13 patients received also chemotherapy. PET scan was performed 40-60 min. after 5-10 mCi of F-18 FDG (i.v.) and SPECT 30 min. after 4.6 mCi of Tl-201 chloride (i.v.). Severe FDG hypometabolism was evident in the irradiated regions, in all patients. Evidence of tumor recurrence was seen in 15 patients by both FDG PET and Thallium 201 SPECT. The ratio of peak pixel uptake of suspected tumor to that of normal cortex for FDG ranged from 0.67 to 1.5 with a mean of 1.02. The ratio of peak pixel uptake of thallium 201 in the suspected lesion to that of the contralateral scalp area ranges from 0.8 to 1.9 with mean of 1.1. There was concordance between the findings of PET and SPECT in 16/18 patients. However, the volume of involvement differs in these patients; most likely secondary to different mechanisms of uptake and both studies may complement each other. Subsequent biopsy/surgery in 11 patients confirmed tumor recurrence in 10 out of 11 patients. The findings suggest that thallium 201 brain SPECT scan can provide similar (but not identical) information regarding brain tumor recurrence in these patients.

  12. PET quantification of the norepinephrine transporter in human brain with (S,S)-18F-FMeNER-D2.

    PubMed

    Moriguchi, Sho; Kimura, Yasuyuki; Ichise, Masanori; Arakawa, Ryosuke; Takano, Harumasa; Seki, Chie; Ikoma, Yoko; Takahata, Keisuke; Nagashima, Tomohisa; Yamada, Makiko; Mimura, Masaru; Suhara, Tetsuya

    2016-12-15

    Norepinephrine transporter (NET) in the brain plays important roles in human cognition and the pathophysiology of psychiatric disorders. Two radioligands, (S,S)-(11)C-MRB and (S,S)-(18)F-FMeNER-D2, have been used for imaging NETs in the thalamus and midbrain (including locus coeruleus) using positron emission topography (PET) in humans. However, NET density in the equally important cerebral cortex has not been well quantified because of unfavorable kinetics with (S,S)-(11)C-MRB and defluorination with (S,S)-(18)F-FMeNER-D2, which can complicate NET quantification in the cerebral cortex adjacent to the skull containing defluorinated (18)F radioactivity. In this study, we have established analysis methods of quantification of NET density in the brain including cerebral cortex using (S,S)-(18)F-FMeNER-D2 PET.

  13. Evaluation of the Dopamine Hypothesis of ADHD with PET Brain Imaging

    SciTech Connect

    Swanson, James

    2010-04-28

    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

  14. Evaluation of the Dopamine Hypothesis of ADHD with PET Brain Imaging

    ScienceCinema

    Swanson, James [University of California, Irvine, California, United States

    2016-07-12

    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

  15. Evaluation of the Dopamine Hypothesis of ADHD with PET Brain Imaging

    SciTech Connect

    Swanson, James

    2010-04-28

    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

  16. Metabolic Brain Covariant Networks as Revealed by FDG-PET with Reference to Resting-State fMRI Networks

    PubMed Central

    Di, Xin

    2012-01-01

    Abstract The human brain is inherently organized as separate networks, as has been widely revealed by resting-state functional magnetic resonance imaging (fMRI). Although the large-scale functional connectivity can be partially explained by the underlying white-matter structural connectivity, the question of whether the underlying functional connectivity is related to brain metabolic factors is still largely unanswered. The present study investigated the presence of metabolic covariant networks across subjects using a set of fluorodeoxyglucose (18F, FDG) positron-emission tomography (PET) images. Spatial-independent component analysis was performed on the subject series of FDG-PET images. A number of networks that were mainly homotopic regions could be identified, including visual, auditory, motor, cerebellar, and subcortical networks. However, the anterior-posterior networks such as the default-mode and left frontoparietal networks could not be observed. Region-of-interest-based correlation analysis confirmed that the intersubject metabolic covariances within the default-mode and left frontoparietal networks were reduced as compared with corresponding time-series correlations using resting-state fMRI from an independent sample. In contrast, homotopic intersubject metabolic covariances observed using PET were comparable to the corresponding fMRI resting-state time-series correlations. The current study provides preliminary illustration, suggesting that the human brain metabolism pertains to organized covariance patterns that might partially reflect functional connectivity as revealed by resting-state blood oxygen level dependent (BOLD). The discrepancy between the PET covariance and BOLD functional connectivity might reflect the differences of energy consumption coupling and ongoing neural synchronization within these brain networks. PMID:23025619

  17. Use of Standardized Uptake Value Ratios Decreases Interreader Variability of [18F] Florbetapir PET Brain Scan Interpretation.

    PubMed

    Nayate, A P; Dubroff, J G; Schmitt, J E; Nasrallah, I; Kishore, R; Mankoff, D; Pryma, D A

    2015-07-01

    Fluorine-18 florbetapir is a recently developed β-amyloid plaque positron-emission tomography imaging agent with high sensitivity, specificity, and accuracy in the detection of moderate-to-frequent cerebral cortical β-amyloid plaque. However, the FDA has expressed concerns about the consistency of interpretation of [(18)F] florbetapir PET brain scans. We hypothesized that incorporating automated cerebral-to-whole-cerebellar standardized uptake value ratios into [(18)F] florbetapir PET brain scan interpretation would reduce this interreader variability. This randomized, blinded-reader study used previously acquired [(18)F] florbetapir scans from 30 anonymized patients who were enrolled in the Alzheimer's Disease Neuroimaging Initiative 2. In 4 separate, blinded-reading sessions, 5 readers classified 30 cases as positive or negative for significant β-amyloid deposition either qualitatively alone or qualitatively with additional adjunct software that determined standardized uptake value ratios. A κ coefficient was used to calculate interreader agreement with and without the use of standardized uptake value ratios. There was complete interreader agreement on 20/30 cases of [(18)F] florbetapir PET brain scans by using qualitative interpretation and on 27/30 scans interpreted with the adjunct use of standardized uptake value ratios. The κ coefficient for the studies read with standardized uptake value ratios (0.92) was significantly higher compared with the qualitatively read studies (0.69, P = .006). Use of standardized uptake value ratios improves interreader agreement in the interpretation of [(18)F] florbetapir images. © 2015 by American Journal of Neuroradiology.

  18. FDG-PET in the Evaluation of Brain Metabolic Changes Induced by Cognitive Stimulation in aMCI Subjects.

    PubMed

    Ciarmiello, Andrea; Gaeta, Maria Chiara; Benso, Francesco; Del Sette, Massimo

    2015-01-01

    Cognitive training has reported to improve cognitive performance in Mild Cognitive Impairment (MCI) as well as in older healthy subjects. 18F-FDG-PET is widely used in the diagnoses of dementia for its ability to identify early metabolic changes. This study was aimed to assess the effect of cognitive stimulation on brain metabolic network and clinical cognitive performance. Thirty aMCI subjects were enrolled in the study and allocated in two groups matched for cognitive profile, sex and schooling and then randomly assigned to the training arm or to the placebo arm. All subjects underwent neuropsychological assessment and PET imaging before and after intervention. We found significant association between brain metabolism and cognitive stimulation in treated aMCI subjects. Brain metabolic changes included Brodmann areas reported to be involved in working memory and attentive processes as well as executive functions. Our study shows that metabolic changes occur earlier than possible clinical changes related to the intervention. 18F-FDG-PET could provide a useful biomarker of response to identify a population of aMCI suitable to respond to treatment, according to most recent data on default network mode and its adaptivity to external stimuli.

  19. Classification of Parkinsonian Syndromes from FDG-PET Brain Data Using Decision Trees with SSM/PCA Features

    PubMed Central

    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. PMID:25918550

  20. Automated reference region extraction and population-based input function for brain [11C]TMSX PET image analyses

    PubMed Central

    Rissanen, Eero; Tuisku, Jouni; Luoto, Pauliina; Arponen, Eveliina; Johansson, Jarkko; Oikonen, Vesa; Parkkola, Riitta; Airas, Laura; Rinne, Juha O

    2015-01-01

    [11C]TMSX ([7-N-methyl-11C]-(E)-8-(3,4,5-trimethoxystyryl)-1,3,7-trimethylxanthine) is a selective adenosine A2A receptor (A2AR) radioligand. In the central nervous system (CNS), A2AR are linked to dopamine D2 receptor function in striatum, but they are also important modulators of inflammation. The golden standard for kinetic modeling of brain [11C]TMSX positron emission tomography (PET) is to obtain arterial input function via arterial blood sampling. However, this method is laborious, prone to errors and unpleasant for study subjects. The aim of this work was to evaluate alternative input function acquisition methods for brain [11C]TMSX PET imaging. First, a noninvasive, automated method for the extraction of gray matter reference region using supervised clustering (SCgm) was developed. Second, a method for obtaining a population-based arterial input function (PBIF) was implemented. These methods were created using data from 28 study subjects (7 healthy controls, 12 multiple sclerosis patients, and 9 patients with Parkinson's disease). The results with PBIF correlated well with original plasma input, and the SCgm yielded similar results compared with cerebellum as a reference region. The clustering method for extracting reference region and the population-based approach for acquiring input for dynamic [11C]TMSX brain PET image analyses appear to be feasible and robust methods, that can be applied in patients with CNS pathology. PMID:25370856

  1. Quantitative analysis of MRI-guided attenuation correction techniques in time-of-flight brain PET/MRI.

    PubMed

    Mehranian, Abolfazl; Arabi, Hossein; Zaidi, Habib

    2016-04-15

    In quantitative PET/MR imaging, attenuation correction (AC) of PET data is markedly challenged by the need of deriving accurate attenuation maps from MR images. A number of strategies have been developed for MRI-guided attenuation correction with different degrees of success. In this work, we compare the quantitative performance of three generic AC methods, including standard 3-class MR segmentation-based, advanced atlas-registration-based and emission-based approaches in the context of brain time-of-flight (TOF) PET/MRI. Fourteen patients referred for diagnostic MRI and (18)F-FDG PET/CT brain scans were included in this comparative study. For each study, PET images were reconstructed using four different attenuation maps derived from CT-based AC (CTAC) serving as reference, standard 3-class MR-segmentation, atlas-registration and emission-based AC methods. To generate 3-class attenuation maps, T1-weighted MRI images were segmented into background air, fat and soft-tissue classes followed by assignment of constant linear attenuation coefficients of 0, 0.0864 and 0.0975 cm(-1) to each class, respectively. A robust atlas-registration based AC method was developed for pseudo-CT generation using local weighted fusion of atlases based on their morphological similarity to target MR images. Our recently proposed MRI-guided maximum likelihood reconstruction of activity and attenuation (MLAA) algorithm was employed to estimate the attenuation map from TOF emission data. The performance of the different AC algorithms in terms of prediction of bones and quantification of PET tracer uptake was objectively evaluated with respect to reference CTAC maps and CTAC-PET images. Qualitative evaluation showed that the MLAA-AC method could sparsely estimate bones and accurately differentiate them from air cavities. It was found that the atlas-AC method can accurately predict bones with variable errors in defining air cavities. Quantitative assessment of bone extraction accuracy based on

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

    NASA Astrophysics Data System (ADS)

    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.

  3. Modifiable Risk Factors and Brain PET Measures of Amyloid and Tau in Non-Demented Adults with Memory Complaints

    PubMed Central

    Merrill, David A.; Siddarth, Prabha; Raji, Cyrus A.; Emerson, Natacha D.; Rueda, Florangel; Ercoli, Linda M.; Miller, Karen J.; Lavretsky, Helen; Harris, Laurel M.; Burggren, Alison C.; Bookheimer, Susan Y.; Barrio, Jorge R.; Small, Gary W.

    2016-01-01

    Objective Exercise and diet impact body composition, but their age-related brain effects are unclear at the molecular imaging level. To address these issues, we determined whether body mass index (BMI), physical activity, and diet relate to brain positron emission tomography (PET) of amyloid plaques and tau tangles using 2-(1-(6-[(2-[F-18]fluoroethyl)(methyl)amino]-2-naphthyl)ethylidene)malononitrile (FDDNP). Methods Volunteers (n = 44, mean age = 62.6 ± 10.7 years) with subjective memory impairment (n = 24) or mild cognitive impairment (MCI; n = 20) were recruited by soliciting for memory complaints. Levels of physical activity and extent of following a Mediterranean-type diet were self-reported. FDDNP-PET scans assessed plaque/tangle binding in Alzheimer’s disease (AD)-associated regions (frontal, parietal, medial and lateral temporal, posterior cingulate). Mixed models controlling for known covariates examined BMI, physical activity, and diet in relation to FDDNP-PET. Results MCI subjects with above normal BMI (>25) had higher FDDNP-PET binding compared to those with normal BMI (1.11(.03) vs 1.08(.03), ES=1.04, t(35)=3.3, p=.002). Greater physical activity was associated with lower FDDNP-PET binding in MCI subjects (1.07(.03) vs 1.11(.03), ES=1.13, t(35) =−3.1, p=.004) but not in subjects with subjective memory impairment (1.07 (.03) vs 1.07(.03), ES=.02, t(35)=−0.1, p=.9). Healthier diet related to lower FDDNP-PET binding, regardless of cognitive status (1.07(.03) vs 1.09(.02), ES=0.72, t(35)=−2.1, p = .04). Conclusion and Relevance These preliminary findings are consistent with a relationship between risk modifiers and brain plaque/tangle deposition in non-demented individuals and supports maintenance of normal body weight, regular physical activity, and healthy diet adherence to protect the brain during aging. PMID:27421618

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

    PubMed

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

    2015-10-01

    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 both functional and anatomical information in a single imaging session. Nevertheless, there is a trade-off between spatial resolution and image quality (contrast and noise), which is dictated mainly by the chosen acquisition and reconstruction protocols. Image reconstruction algorithms using spherical symmetric basis functions (blobs) for image representation have a number of additional parameters that impact both the qualitative and quantitative image characteristics. Hence, a detailed investigation of the blob-based reconstruction characteristics using different parameters is needed to achieve optimal reconstruction results. This work evaluated the impact of a range of blob parameters on image quality and quantitative accuracy of brain PET images acquired on the Ingenuity Time-of-Flight (TOF) PET/MR system. Two different phantoms were used to simulate brain imaging applications. Image contrast and noise characteristics were assessed using an image quality phantom. Quantitative performance in a clinical setting was investigated using the Hoffman 3D brain phantom at various count levels. Furthermore, the visual quality of four clinical studies was scored blindly by two experienced physicians to qualitatively evaluate the influence of different reconstruction protocols, hereby providing indications on parameters producing the best image quality. Quantitative evaluation using the image quality phantom showed that larger basis function radii result in lower contrast recovery (∼2%) and lower variance levels (∼15%). The brain phantom and clinical studies confirmed these observations since lower contrast was seen between anatomical structures. High and low count statistics

  5. Brain metastases detectability of routine whole body (18)F-FDG PET and low dose CT scanning in 2502 asymptomatic patients with solid extracranial tumors.

    PubMed

    Bochev, Pavel; Klisarova, Aneliya; Kaprelyan, Ara; Chaushev, Borislav; Dancheva, Zhivka

    2012-01-01

    As fluorine-18-fluorodesoxyglucose positron emission tomography/computed tomography ( (18)F-FDG PET/CT) is gaining wider availability, more and more patients with malignancies undergo whole body PET/CT, mostly to assess tumor spread in the rest of the body, but not in the brain. Brain is a common site of metastatic spread in patients with solid extracranial tumors. Gold standard in the diagnosis of brain metastases remains magnetic resonance imaging (MRI). However MRI is not routinely indicated and is not available for all cancer patients. Fluorine-18-FDG PET is considered as having poor sensitivity in detecting brain metastases, but this may not be true for PET/CT. The aim of our study was to assess the value of (18)F-FDG PET/CT in the detection of brain metastases found by whole body scan including the brain, in patients with solid extracranial neoplasms. A total of 2502 patients with solid extracranial neoplasms were studied. All patients underwent a routine whole body (18)F-FDG PET/CT scan with the whole brain included in the scanned field. Patients with known or suspected brain metastases were preliminary excluded from the study. Hypermetabolic and ring-like brain lesions on the PET scan were considered as metastases. Lesions with CT characteristics of brain metastases were regarded as such irrespective of their metabolic pattern. Lesions in doubt were verified by MRI during first testing or on follow-up or by operation. Our results showed that brain lesions, indicative of and verified to be metastases were detected in 25 out of the 2502 patients (1%), with lung cancer being the most common primary. Twenty three out of these 25 patients had no neurological symptoms by the time of the scan. The detection rate of brain metastases was relatively low, but information was obtained with a minimum increase of radiation burden. In conclusion, whole body (18)F-FDG PET/CT detected brain metastases in 1% of the patients if brain was included in the scanned field. Brain

  6. Development of a New Radiofluorinated Quinoline Analog for PET Imaging of Phosphodiesterase 5 (PDE5) in Brain

    PubMed Central

    Liu, Jianrong; Wenzel, Barbara; Dukic-Stefanovic, Sladjana; Teodoro, Rodrigo; Ludwig, Friedrich-Alexander; Deuther-Conrad, Winnie; Schröder, Susann; Chezal, Jean-Michel; Moreau, Emmanuel; Brust, Peter; Maisonial-Besset, Aurélie

    2016-01-01

    Phosphodiesterases (PDEs) are enzymes that play a major role in cell signalling by hydrolysing the secondary messengers cyclic adenosine monophosphate (cAMP) and/or cyclic guanosine monophosphate (cGMP) throughout the body and brain. Altered cyclic nucleotide-mediated signalling has been associated with a wide array of disorders, including neurodegenerative disorders. Recently, PDE5 has been shown to be involved in neurodegenerative disorders such as Alzheimer’s disease, but its precise role has not been elucidated yet. To visualize and quantify the expression of this enzyme in brain, we developed a radiotracer for specific PET imaging of PDE5. A quinoline-based lead compound has been structurally modified resulting in the fluoroethoxymethyl derivative ICF24027 with high inhibitory activity towards PDE5 (IC50 = 1.86 nM). Radiolabelling with fluorine-18 was performed by a one-step nucleophilic substitution reaction using a tosylate precursor (RCY(EOB) = 12.9% ± 1.8%; RCP > 99%; SA(EOS) = 70–126 GBq/μmol). In vitro autoradiographic studies of [18F]ICF24027 on different mouse tissue as well as on porcine brain slices demonstrated a moderate specific binding to PDE5. In vivo studies in mice revealed that [18F]ICF24027 was metabolized under formation of brain penetrable radiometabolites making the radiotracer unsuitable for PET imaging of PDE5 in brain. PMID:27110797

  7. Improved attenuation correction for freely moving animal brain PET studies using a virtual scanner geometry

    NASA Astrophysics Data System (ADS)

    Angelis, Georgios I.; Ryder, William J.; Kyme, Andre Z.; Fulton, Roger R.; Meikle, Steven R.

    2014-03-01

    Attenuation correction in positron emission tomography brain imaging of freely moving animals can be very challenging since the body of the animal is often within the field of view and introduces a non negligible atten- uating factor that can degrade the quantitative accuracy of the reconstructed images. An attractive approach that avoids the need for a transmission scan involves the generation of the convex hull of the animal's head based on the reconstructed emission images. However, this approach ignores the potential attenuation introduced by the animal's body. In this work, we propose a virtual scanner geometry, which moves in synchrony with the animal's head and discriminates between those events that traverse only the animal's head (and therefore can be accurately compensated for attenuation) and those that might have also traversed the animal's body. For each pose a new virtual scanner geometry was defined and therefore a new system matrix was calculated leading to a time-varying system matrix. This new approach was evaluated on phantom data acquired on the microPET Focus 220 scanner using a custom-made rat phantom. Results showed that when the animal's body is within the FOV and not accounted for during attenuation correction it can lead to bias of up to 10%. On the contrary, at- tenuation correction was more accurate when the virtual scanner was employed leading to improved quantitative estimates (bias <2%), without the need to account for the animal's body.

  8. Motion correction of PET brain images through deconvolution: I. Theoretical development and analysis in software simulations

    NASA Astrophysics Data System (ADS)

    Faber, T. L.; Raghunath, N.; Tudorascu, D.; Votaw, J. R.

    2009-02-01

    Image quality is significantly degraded even by small amounts of patient motion in very high-resolution PET scanners. Existing correction methods that use known patient motion obtained from tracking devices either require multi-frame acquisitions, detailed knowledge of the scanner, or specialized reconstruction algorithms. A deconvolution algorithm has been developed that alleviates these drawbacks by using the reconstructed image to estimate the original non-blurred image using maximum likelihood estimation maximization (MLEM) techniques. A high-resolution digital phantom was created by shape-based interpolation of the digital Hoffman brain phantom. Three different sets of 20 movements were applied to the phantom. For each frame of the motion, sinograms with attenuation and three levels of noise were simulated and then reconstructed using filtered backprojection. The average of the 20 frames was considered the motion blurred image, which was restored with the deconvolution algorithm. After correction, contrast increased from a mean of 2.0, 1.8 and 1.4 in the motion blurred images, for the three increasing amounts of movement, to a mean of 2.5, 2.4 and 2.2. Mean error was reduced by an average of 55% with motion correction. In conclusion, deconvolution can be used for correction of motion blur when subject motion is known.

  9. Performance Enhancement of the RatCAP Awake Rate Brain PET System

    SciTech Connect

    Vaska, P.; Vaska, P.; Woody, C.; Schlyer, D.; Radeka, V.; O'Connor, P.; Park, S.-J.; Pratte, J.-F.; Junnarkar, M.; Purschke, S.; Southekal, S.; Stoll, S.; Schiffer, W.; Neill, J.; Wharton, D.; Myers, N.; Wiley, S.; Kandasamy, A.; Fried, J.; Krishnamoorthy, S. Kriplani, A.; Maramraju, S.; Lecomte, R.; Fontaine, R.

    2011-03-01

    The first full prototype of the RatCAP PET system, designed to image the brain of a rat while conscious, has been completed. Initial results demonstrated excellent spatial resolution, 1.8 mm FWHM with filtered backprojection and <1.5 mm FWHM with a Monte Carlo based MLEM method. However, noise equivalent countrate studies indicated the need for better timing to mitigate the effect of randoms. Thus, the front-end ASIC has been redesigned to minimize time walk, an accurate coincidence time alignment method has been implemented, and a variance reduction technique for the randoms is being developed. To maximize the quantitative capabilities required for neuroscience, corrections are being implemented and validated for positron range and photon noncollinearity, scatter (including outside the field of view), attenuation, randoms, and detector efficiency (deadtime is negligible). In addition, a more robust and compact PCI-based optical data acquisition system has been built to replace the original VME-based system while retaining the linux-based data processing and image reconstruction codes. Finally, a number of new animal imaging experiments have been carried out to demonstrate the performance of the RatCAP in real imaging situations, including an F-18 fluoride bone scan, a C-11 raclopride scan, and a dynamic C-11 methamphetamine scan.

  10. Image derived input functions for dynamic High Resolution Research Tomograph PET brain studies.

    PubMed

    Mourik, Jurgen E M; van Velden, Floris H P; Lubberink, Mark; Kloet, Reina W; van Berckel, Bart N M; Lammertsma, Adriaan A; Boellaard, Ronald

    2008-12-01

    The High Resolution Research Tomograph (HRRT) is a dedicated human brain positron emission tomography (PET) scanner. The aim of the present study was to validate the use of image derived input functions (IDIF) as an alternative for arterial sampling for HRRT human brain studies. To this end, IDIFs were extracted from 3D ordinary Poisson ordered subsets expectation maximization (OP-OSEM) and reconstruction based partial volume corrected (PVC) OP-OSEM images. IDIFs, either derived directly from regions of interest or further calibrated using manual samples taken during scans, were evaluated for dynamic [(11)C]flumazenil data (n=6). Results obtained with IDIFs were compared with those obtained using blood sampler input functions (BSIF). These comparisons included areas under the curve (AUC) for peak (0-3.3 min) and tail (3.3-55.0 min). In addition, slope, intercept and Pearson's correlation coefficient of tracer kinetic analysis results based on IDIF and BSIF were calculated for each subject. Good peak AUC ratios (0.83+/-0.21) between IDIF and BSIF were found for calibrated IDIFs extracted from OP-OSEM images. This combination of IDIFs and images also provided good slope values (1.07+/-0.11). Improved resolution, as obtained with PVC OP-OSEM, changed AUC ratios to 1.14+/-0.35 and, for tracer kinetic analysis, slopes changed to 0.95+/-0.13. For all reconstructions, non-calibrated IDIFs gave poorer results (>61+/-34% higher slopes) compared with calibrated IDIFs. The results of this study indicate that the use of IDIFs, extracted from OP-OSEM or PVC OP-OSEM images, is feasible for dynamic HRRT data, thereby obviating the need for online arterial sampling.

  11. Cerebral 5-HT release correlates with [(11)C]Cimbi36 PET measures of 5-HT2A receptor occupancy in the pig brain.

    PubMed

    Jørgensen, Louise M; Weikop, Pia; Villadsen, Jonas; Visnapuu, Tanel; Ettrup, Anders; Hansen, Hanne D; Baandrup, Anders O; Andersen, Flemming L; Bjarkam, Carsten R; Thomsen, Carsten; Jespersen, Bo; Knudsen, Gitte M

    2017-02-01

    Positron emission tomography (PET) can, when used with appropriate radioligands, non-invasively generate temporal and spatial information about acute changes in brain neurotransmitter systems. We for the first time evaluate the novel 5-HT2A receptor agonist PET radioligand, [(11)C]Cimbi-36, for its sensitivity to detect changes in endogenous cerebral 5-HT levels, as induced by different pharmacological challenges. To enable a direct translation of PET imaging data to changes in brain 5-HT levels, we calibrated the [(11)C]Cimbi-36 PET signal in the pig brain by simultaneous measurements of extracellular 5-HT levels with microdialysis and [(11)C]Cimbi-36 PET after various acute interventions (saline, citalopram, citalopram + pindolol, fenfluramine). In a subset of pigs, para-chlorophenylalanine pretreatment was given to deplete cerebral 5-HT. The interventions increased the cerebral extracellular 5-HT levels to 2-11 times baseline, with fenfluramine being the most potent pharmacological enhancer of 5-HT release, and induced a varying degree of decline in [(11)C]Cimbi-36 binding in the brain, consistent with the occupancy competition model. The observed correlation between changes in the extracellular 5-HT level in the pig brain and the 5-HT2A receptor occupancy indicates that [(11)C]Cimbi-36 binding is sensitive to changes in endogenous 5-HT levels, although only detectable with PET when the 5-HT release is sufficiently high.

  12. [PET scan and NMR spectroscopy for the differential diagnosis between brain radiation necrosis and tumour recurrence after stereotactic irradiation of brain metastases: Place in the decision tree].

    PubMed

    Menoux, I; Noël, G; Namer, I; Antoni, D

    2017-08-01

    After stereotactic radiation therapy for brain metastases, one of the complications is radionecrosis. Differential diagnosis with tumour recurrence can be helped by different methods of imaging, although histology remains the gold standard. According to the treatment centres, practice diverges. The objective of this single-centre retrospective study was to define the power of MRI, PET scan and NMR spectroscopy to establish a decision tree. This study included patients who underwent stereotactic radiation therapy for brain metastases, and required, during follow-up, both a PET scan and NMR spectroscopy in order to differentiate a radiation necrosis and tumour recurrence. From 2010 to 2015, 25 patients were consistent with these criteria. Conventional MRI technique, with the T1/T2 mismatch criterion, had a specificity of 75% and a sensitivity of only 44%. A lesion quotient greater than 0.3 diagnosed a recurrence with a sensitivity of 92%. PET scan combined the best sensitivity and specificity, respectively of 92% and 69%. Whatever the thresholds used in NMR spectroscopy for choline/N-acetylaspartate and choline/creatin ratios, the power of this imaging modality did not exceed that of PET scan. The criteria described in conventional MRI cannot by themselves establish the differential diagnosis. In first intention in case of doubt, PET scan should be done, combining the best sensitivity and specificity, whereas NMR spectroscopy used in combination does not improve these factors. Copyright © 2017 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

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

    PubMed

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

    2016-08-01

    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(-)/K222 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 (5mg/kg iv injection at 30min 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.

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

    PubMed

    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

  15. Advancing PET science for new measures of brain function. Progress report, January 1, 1994--December 31, 1994

    SciTech Connect

    Kuhl, D.E.

    1994-10-01

    This project has continued the development of new chemistry and imaging physics applicable to PET studies of the human brain. In basic radiochemistry research, the authors have developed a modified approach to solid-phase supported [{sup 11}C]methylation system, in part dependent on the design, fabrication and validation of new small, sensitive and accurate positron detectors useful in tracking the flow of radioactivity through the synthesis apparatus. Radiopharmaceutical efforts have resulted in synthesis of new tracers of mitochondrial enzymes. For evaluation of new PET radiotracers, the authors have applied new models of unilateral brain lesions using quinolinic acid and MPP+, as models of neurodegenerative diseases. In the physics and data analysis research area the authors have developed faster and more accurate means of performing image reconstruction for use with both emission and transmission data. The authors are optimizing acquisition and kinetic modeling strategies for new radiotracers. The authors also have implemented and proven the utility of performing task switching during PET CBF activation studies for the purpose of enhancing signal-to-noise and greater detectability of areas of activation. The authors also working on routines for standardization of analysis strategies for group vs. group and individual vs. group comparisons.

  16. Kinetics of brain nicotine accumulation in dependent and nondependent smokers assessed with PET and cigarettes containing 11C-nicotine

    PubMed Central

    Rose, Jed E.; Mukhin, Alexey G.; Lokitz, Stephen J.; Turkington, Timothy G.; Herskovic, Joseph; Behm, Frederique M.; Garg, Sudha; Garg, Pradeep K.

    2010-01-01

    Tobacco smoking is a chronic, relapsing disorder that constitutes one of the primary preventable causes of death in developed countries. Two of the popular hypotheses to explain the development and maintenance of strong nicotine dependence in cigarette smokers posit (i) a rapid brain nicotine accumulation during cigarette smoking and/or (ii) puff-associated spikes in brain nicotine concentration. To address these hypotheses, we investigated the dynamics of nicotine accumulation in the smoker's brain during actual cigarette smoking using PET with 3-s temporal resolution and 11C-nicotine loaded into cigarettes. The results of the study, performed in 13 dependent smokers (DS) and 10 nondependent smokers (NDS), suggest that puff-associated spikes in the brain nicotine concentration do not occur during habitual cigarette smoking. Despite the presence of a puff-associated oscillation in the rate of nicotine accumulation, brain nicotine concentration gradually increases during cigarette smoking. The results further suggest that DS have a slower process of brain nicotine accumulation than NDS because they have slower nicotine washout from the lungs and that DS have a tendency to compensate for their slower rate of brain nicotine accumulation compared with NDS by inhaling a larger volume of smoke. For these reasons, smokers’ dependence on cigarette smoking, or the resistance of NDS to becoming dependent, cannot be explained solely by a faster brain nicotine accumulation. PMID:20212132

  17. Whole-body biodistribution and the influence of body activity on brain kinetic analysis of the (11)C-PiB PET scan.

    PubMed

    Akamatsu, Go; Nishio, Tomoyuki; Adachi, Kazuhiko; Ikari, Yasuhiko; Senda, Michio

    2017-09-11

    Dynamic (11)C-PiB PET imaging with kinetic analysis has been performed for accurate quantification of amyloid binding in patients with Alzheimer's disease (AD). In this study, we measured the whole-body biodistribution of (11)C-PiB in nine subjects. We then evaluated the effect of body activity on quantitative accuracy of brain (11)C-PiB three-dimensional (3D) dynamic PET. Based on clinical biodistribution data, we conducted phantom experiments to estimate the effect of body activity on quantification of the brain 3D dynamic (11)C-PiB PET data and the error introduced by body activity using six different PET camera models. One of the PET cameras was used to acquire (11)C-PiB brain 3D dynamic PET data on a patient with AD. We calculated the distribution volume ratio (DVR) in two kinetic methods using both the original human time-activity-curve (TAC) data and the TAC corrected for the error caused by body activity. In the early phase, both healthy subjects and patients with AD showed a biodistribution of (11)C-PiB that reflected regional blood flow. In the simulated early phase of the phantom experiments, activity outside the field of view led to a maximum 6.0% overestimation of brain activity in the vertex region. Conversely, the effect of body activity on the DVR estimate was small (≤1.2%), probably because the tested kinetic methods did not rely heavily on early phase data. These results indicate that the effect of body activity on brain (11)C-PiB PET quantification is generally small and that it depends on the method of kinetic analysis, the region of interest, and the PET camera model used.

  18. Comparison of brain MRI and 18F-FDG PET in the differential diagnosis of multiple system atrophy from Parkinson's disease.

    PubMed

    Kwon, Kyum-Yil; Choi, Choong G; Kim, Jae S; Lee, Myoung C; Chung, Sun J

    2007-12-01

    To investigate the diagnostic value of brain magnetic resonance image (MRI) and (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) in the differentiation of multiple system atrophy (MSA) from Parkinson's disease (PD). Thirty-five patients with MSA (23 MSA-P and 12 MSA-C) and 17 patients with PD were included in this study. Overall correct diagnosis rates between clinical and imaging diagnosis among MSA-P, MSA-C, and PD patients were 80% for visual MRI analysis, 88.5% for visual (18)F-FDG PET analysis, and 84.3% for SPM-supported analysis of (18)F-FDG PET. The sensitivity of brain MRI, and visual and SPM analysis of (18)F-FDG PET in differentiating MSA from PD was 72.7%, 90.9%, and 95.5%, respectively, the specificity was 100% for each imaging analysis, the positive predictive value was 100% for each imaging analysis, and the negative predictive value was 60%, 81.8%, and 90%, respectively. Our results suggest that brain MRI and (18)F-FDG PET are diagnostically useful in differentiating MSA (MSA-P and MSA-C) from PD, and indicate that (18)F-FDG PET has a tendency toward higher sensitivity compared to brain MRI, but a larger longitudinal study including pathological data will be required to confirm our findings.

  19. Translocator protein (18 kDa) polymorphism (rs6971) explains in-vivo brain binding affinity of the PET radioligand [(18)F]-FEPPA.

    PubMed

    Mizrahi, Romina; Rusjan, Pablo M; Kennedy, James; Pollock, Bruce; Mulsant, Benoit; Suridjan, Ivonne; De Luca, Vincenzo; Wilson, Alan A; Houle, Sylvain

    2012-06-01

    [(18)F]-FEPPA binds to the 18-kDa translocator protein (TSPO) and is used in positron emission tomography (PET) to detect microglial activation. However, quantitative interpretations of the PET signal with new generation TSPO PET radioligands are confounded by large interindividual variability in binding affinity. This presents as a trimodal distribution, reflecting high-affinity binders (HABs), low-affinity binder (LAB), and mixed-affinity binders (MABs). Here, we show that one polymorphism (rs6971) located in exon 4 of the TSPO gene, which results in a nonconservative amino-acid substitution from alanine to threonine (Ala147Thr) in the TSPO protein, predicts [(18)F]-FEPPA total distribution volume in human brains. In addition, [(18)F]-FEPPA exhibits clearly different features in the shape of the time activity curves between genetic groups. Testing for the rs6971 polymorphism may allow quantitative interpretation of TSPO PET studies with new generation of TSPO PET radioligands.

  20. Translocator protein (18 kDa) polymorphism (rs6971) explains in-vivo brain binding affinity of the PET radioligand [18F]-FEPPA

    PubMed Central

    Mizrahi, Romina; Rusjan, Pablo M; Kennedy, James; Pollock, Bruce; Mulsant, Benoit; Suridjan, Ivonne; De Luca, Vincenzo; Wilson, Alan A; Houle, Sylvain

    2012-01-01

    [18F]-FEPPA binds to the 18-kDa translocator protein (TSPO) and is used in positron emission tomography (PET) to detect microglial activation. However, quantitative interpretations of the PET signal with new generation TSPO PET radioligands are confounded by large interindividual variability in binding affinity. This presents as a trimodal distribution, reflecting high-affinity binders (HABs), low-affinity binder (LAB), and mixed-affinity binders (MABs). Here, we show that one polymorphism (rs6971) located in exon 4 of the TSPO gene, which results in a nonconservative amino-acid substitution from alanine to threonine (Ala147Thr) in the TSPO protein, predicts [18F]-FEPPA total distribution volume in human brains. In addition, [18F]-FEPPA exhibits clearly different features in the shape of the time activity curves between genetic groups. Testing for the rs6971 polymorphism may allow quantitative interpretation of TSPO PET studies with new generation of TSPO PET radioligands. PMID:22472607

  1. Using PET with 18F-AV-45 (florbetapir) to quantify brain amyloid load in a clinical environment.

    PubMed

    Camus, V; Payoux, P; Barré, L; Desgranges, B; Voisin, T; Tauber, C; La Joie, R; Tafani, M; Hommet, C; Chételat, G; Mondon, K; de La Sayette, V; Cottier, J P; Beaufils, E; Ribeiro, M J; Gissot, V; Vierron, E; Vercouillie, J; Vellas, B; Eustache, F; Guilloteau, D

    2012-04-01

    Positron emission tomography (PET) imaging of brain amyloid load has been suggested as a core biomarker for Alzheimer's disease (AD). The aim of this study was to test the feasibility of using PET imaging with (18)F-AV-45 (florbetapir) in a routine clinical environment to differentiate between patients with mild to moderate AD and mild cognitive impairment (MCI) from normal healthy controls (HC). In this study, 46 subjects (20 men and 26 women, mean age of 69.0 ± 7.6 years), including 13 with AD, 12 with MCI and 21 HC subjects, were enrolled from three academic memory clinics. PET images were acquired over a 10-min period 50 min after injection of florbetapir (mean ± SD of radioactivity injected, 259 ± 57 MBq). PET images were assessed visually by two individuals blinded to any clinical information and quantitatively via the standard uptake value ratio (SUVr) in the specific regions of interest, which were defined in relation to the cerebellum as the reference region. The mean values of SUVr were higher in AD patients (median 1.20, Q1-Q3 1.16-1.30) than in HC subjects (median 1.05, Q1-Q3 1.04-1.08; p = 0.0001) in the overall cortex and all cortical regions (precuneus, anterior and posterior cingulate, and frontal median, temporal, parietal and occipital cortex). The MCI subjects also showed a higher uptake of florbetapir in the posterior cingulate cortex (median 1.06, Q1-Q3 0.97-1.28) compared with HC subjects (median 0.95, Q1-Q3 0.82-1.02; p = 0.03). Qualitative visual assessment of the PET scans showed a sensitivity of 84.6% (95% CI 0.55-0.98) and a specificity of 38.1% (95% CI 0.18-0.62) for discriminating AD patients from HC subjects; however, the quantitative assessment of the global cortex SUVr showed a sensitivity of 92.3% and specificity of 90.5% with a cut-off value of 1.122 (area under the curve 0.894). These preliminary results suggest that PET with florbetapir is a safe and suitable biomarker for AD that can be used routinely in a clinical

  2. Predicting conversion from MCI to AD with FDG-PET brain images at different prodromal stages.

    PubMed

    Cabral, Carlos; Morgado, Pedro M; Campos Costa, Durval; Silveira, Margarida

    2015-03-01

    Early diagnosis of Alzheimer disease (AD), while still at the stage known as mild cognitive impairment (MCI), is important for the development of new treatments. However, brain degeneration in MCI evolves with time and differs from patient to patient, making early diagnosis a very challenging task. Despite these difficulties, many machine learning techniques have already been used for the diagnosis of MCI and for predicting MCI to AD conversion, but the MCI group used in previous works is usually very heterogeneous containing subjects at different stages. The goal of this paper is to investigate how the disease stage impacts on the ability of machine learning methodologies to predict conversion. After identifying the converters and estimating the time of conversion (TC) (using neuropsychological test scores), we devised 5 subgroups of MCI converters (MCI-C) based on their temporal distance to the conversion instant (0, 6, 12, 18 and 24 months before conversion). Next, we used the FDG-PET images of these subgroups and trained classifiers to distinguish between the MCI-C at different stages and stable non-converters (MCI-NC). Our results show that MCI to AD conversion can be predicted as early as 24 months prior to conversion and that the discriminative power of the machine learning methods decreases with the increasing temporal distance to the TC, as expected. These findings were consistent for all the tested classifiers. Our results also show that this decrease arises from a reduction in the information contained in the regions used for classification and by a decrease in the stability of the automatic selection procedure.

  3. Attenuation correction for freely moving small animal brain PET studies based on a virtual scanner geometry

    NASA Astrophysics Data System (ADS)

    Angelis, G. I.; Kyme, A. Z.; Ryder, W. J.; Fulton, R. R.; Meikle, S. R.

    2014-10-01

    Attenuation correction in positron emission tomography brain imaging of freely moving animals is a very challenging problem since the torso of the animal is often within the field of view and introduces a non negligible attenuating factor that can degrade the quantitative accuracy of the reconstructed images. In the context of unrestrained small animal imaging, estimation of the attenuation correction factors without the need for a transmission scan is highly desirable. An attractive approach that avoids the need for a transmission scan involves the generation of the hull of the animal’s head based on the reconstructed motion corrected emission images. However, this approach ignores the attenuation introduced by the animal’s torso. In this work, we propose a virtual scanner geometry which moves in synchrony with the animal’s head and discriminates between those events that traversed only the animal’s head (and therefore can be accurately compensated for attenuation) and those that might have also traversed the animal’s torso. For each recorded pose of the animal’s head a new virtual scanner geometry is defined and therefore a new system matrix must be calculated leading to a time-varying system matrix. This new approach was evaluated on phantom data acquired on the microPET Focus 220 scanner using a custom-made phantom and step-wise motion. Results showed that when the animal’s torso is within the FOV and not appropriately accounted for during attenuation correction it can lead to bias of up to 10% . Attenuation correction was more accurate when the virtual scanner was employed leading to improved quantitative estimates (bias < 2%), without the need to account for the attenuation introduced by the extraneous compartment. Although the proposed method requires increased computational resources, it can provide a reliable approach towards quantitatively accurate attenuation correction for freely moving animal studies.

  4. Measuring specific receptor binding of a PET radioligand in human brain without pharmacological blockade: The genomic plot

    PubMed Central

    Veronese, Mattia; Zanotti-Fregonara, Paolo; Rizzo, Gaia; Bertoldo, Alessandra; Innis, Robert B.; Turkheimer, Federico E.

    2016-01-01

    PET studies allow in vivo imaging of the density of brain receptor species. The PET signal, however, is the sum of the fraction of radioligand that is specifically bound to the target receptor and the non-displaceable fraction (i.e. the non-specifically bound radioligand plus the free ligand in tissue). Therefore, measuring the non-displaceable fraction, which is generally assumed to be constant across the brain, is a necessary step to obtain regional estimates of the specific fractions. The nondisplaceable binding can be directly measured if a reference region, i.e. a region devoid of any specific binding, is available. Many receptors are however widely expressed across the brain, and a true reference region is rarely available. In these cases, the nonspecific binding can be obtained after competitive pharmacological blockade, which is often contraindicated in humans. In this work we introduce the genomic plot for estimating the nondisplaceable fraction using baseline scans only. The genomic plot is a transformation of the Lassen graphical method in which the brain maps of mRNA transcripts of the target receptor obtained from the Allen brain atlas are used as a surrogate measure of the specific binding. Thus, the genomic plot allows the calculation of the specific and nondisplaceable components of radioligand uptake without the need of pharmacological blockade. We first assessed the statistical properties of the method with computer simulations. Then we sought ground-truth validation using human PET datasets of seven different neuroreceptor radioligands, where nonspecific fractions were either obtained separately using drug displacement or available from a true reference region. The population nondisplaceable fractions estimated by the genomic plot were very close to those measured by actual human blocking studies (mean relative difference between 2% and 7%). However, these estimates were valid only when mRNA expressions were predictive of protein levels (i

  5. Measuring specific receptor binding of a PET radioligand in human brain without pharmacological blockade: The genomic plot.

    PubMed

    Veronese, Mattia; Zanotti-Fregonara, Paolo; Rizzo, Gaia; Bertoldo, Alessandra; Innis, Robert B; Turkheimer, Federico E

    2016-04-15

    PET studies allow in vivo imaging of the density of brain receptor species. The PET signal, however, is the sum of the fraction of radioligand that is specifically bound to the target receptor and the non-displaceable fraction (i.e. the non-specifically bound radioligand plus the free ligand in tissue). Therefore, measuring the non-displaceable fraction, which is generally assumed to be constant across the brain, is a necessary step to obtain regional estimates of the specific fractions. The nondisplaceable binding can be directly measured if a reference region, i.e. a region devoid of any specific binding, is available. Many receptors are however widely expressed across the brain, and a true reference region is rarely available. In these cases, the nonspecific binding can be obtained after competitive pharmacological blockade, which is often contraindicated in humans. In this work we introduce the genomic plot for estimating the nondisplaceable fraction using baseline scans only. The genomic plot is a transformation of the Lassen graphical method in which the brain maps of mRNA transcripts of the target receptor obtained from the Allen brain atlas are used as a surrogate measure of the specific binding. Thus, the genomic plot allows the calculation of the specific and nondisplaceable components of radioligand uptake without the need of pharmacological blockade. We first assessed the statistical properties of the method with computer simulations. Then we sought ground-truth validation using human PET datasets of seven different neuroreceptor radioligands, where nonspecific fractions were either obtained separately using drug displacement or available from a true reference region. The population nondisplaceable fractions estimated by the genomic plot were very close to those measured by actual human blocking studies (mean relative difference between 2% and 7%). However, these estimates were valid only when mRNA expressions were predictive of protein levels (i

  6. Cerebrospinal fluid lactate levels and brain [18F]FDG PET hypometabolism within the default mode network in Alzheimer's disease.

    PubMed

    Liguori, Claudio; Chiaravalloti, Agostino; Sancesario, Giuseppe; Stefani, Alessandro; Sancesario, Giulia Maria; Mercuri, Nicola Biagio; Schillaci, Orazio; Pierantozzi, Mariangela

    2016-10-01

    It has been suggested that neuronal energy metabolism may be involved in Alzheimer's disease (AD). In this view, the finding of increased cerebrospinal fluid (CSF) lactate levels in AD patients has been considered the result of energetic metabolism dysfunction. Here, we investigated the relationship between neuronal energy metabolism, as measured via CSF lactate levels, and cerebral glucose metabolism, as stated at the 2-deoxy-2-(18F)fluoro-D-glucose positron emission tomography ([18F]FDG PET) in AD patients. AD patients underwent lumbar puncture to measure CSF lactate levels and [18F]FDG PET to assess brain glucose metabolism. CSF and PET data were compared to controls. Since patients were studied at rest, we specifically investigated brain areas active in rest-condition owing to the Default Mode Network (DMN). We correlated the CSF lactate concentrations with the [18F]FDG PET data in brain areas owing to the DMN, using sex, age, disease duration, Mini Mental State Examination, and CSF levels of tau proteins and beta-amyloid as covariates. AD patients (n = 32) showed a significant increase of CSF lactate levels compared to Control 1 group (n = 28). They also showed brain glucose hypometabolism in the DMN areas compared to Control 2 group (n = 30). Within the AD group we found the significant correlation between increased CSF lactate levels and glucose hypometabolism in Broadman areas (BA) owing to left medial prefrontal cortex (BA10, mPFC), left orbitofrontal cortex (BA11, OFC), and left parahippocampal gyrus (BA 35, PHG). We found high CSF levels of lactate and glucose hypometabolism within the DMN in AD patients. Moreover, we found a relationship linking the increased CSF lactate and the reduced glucose consumption in the left mPFC, OFC and PHG, owing to the anterior hub of DMN. These findings could suggest that neural glucose hypometabolism may affect the DMN efficiency in AD, also proposing the possible role of damaged brain energetic machine in

  7. DHA brain uptake and APOE4 status: a PET study with [1-(11)C]-DHA.

    PubMed

    Yassine, Hussein N; Croteau, Etienne; Rawat, Varun; Hibbeln, Joseph R; Rapoport, Stanley I; Cunnane, Stephen C; Umhau, John C

    2017-03-23

    The apolipoprotein E ɛ4 (APOE4) allele is the strongest genetic risk factor identified for developing Alzheimer's disease (AD). Among brain lipids, alteration in the ω-3 polyunsaturated fatty acid docosahexaenoic acid (DHA) homeostasis is implicated in AD pathogenesis. APOE4 may influence both brain DHA metabolism and cognitive outcomes. Using positron emission tomography, regional incorporation coefficients (k*), rates of DHA incorporation from plasma into the brain using [1-(11)C]-DHA (J in), and regional cerebral blood flow using [(15)O]-water were measured in 22 middle-aged healthy adults (mean age 35 years, range 19-65 years). Data were partially volume error-corrected for brain atrophy. APOE4 phenotype was determined by protein expression, and unesterified DHA concentrations were quantified in plasma. An exploratory post hoc analysis of the effect of APOE4 on DHA brain kinetics was performed. The mean global gray matter DHA incorporation coefficient, k*, was significantly higher (16%) among APOE4 carriers (n = 9) than among noncarriers (n = 13, p = 0.046). Higher DHA incorporation coefficients were observed in several brain regions, particularly in the entorhinal subregion, an area affected early in AD pathogenesis. Cerebral blood flow, unesterified plasma DHA, and whole brain DHA incorporation rate (J in) did not differ significantly between the APOE groups. Our findings suggest an increase in the DHA incorporation coefficient in several brain regions in APOE4 carriers. These findings may contribute to understanding how APOE4 genotypes affect AD risk.

  8. Incidence of Brain Metastases on Follow-up (18)F-FDG PET/CT Scans of Non-Small Cell Lung Cancer Patients: Should We Include the Brain?

    PubMed

    Nia, Emily S; Garland, Linda L; Eshghi, Naghmehossadat; Nia, Benjamin B; Avery, Ryan J; Kuo, Phillip H

    2017-09-01

    The brain is the most common site of distant metastasis from lung cancer. Thus, MRI of the brain at initial staging is routinely performed, but if this examination is negative a follow-up examination is often not performed. This study evaluates the incidence of asymptomatic brain metastases in non-small cell lung cancer patients detected on follow-up (18)F-FDG PET/CT scans. Methods: In this Institutional Review Board-approved retrospective review, all vertex to thigh (18)F-FDG PET/CT scans in patients with all subtypes of lung cancer from August 2014 to August 2016 were reviewed. A total of 1,175 (18)F-FDG PET/CT examinations in 363 patients were reviewed. Exclusion criteria included brain metastases on initial staging, histologic subtype of small-cell lung cancer, and no follow-up (18)F-FDG PET/CT examinations. After our exclusion criteria were applied, a total of 809 follow-up (18)F-FDG PET/CT scans in 227 patients were included in the final analysis. The original report of each (18)F-FDG PET/CT study was reviewed for the finding of brain metastasis. The finding of a new brain metastasis prompted a brain MRI, which was reviewed to determine the accuracy of the (18)F-FDG PET/CT. Results: Five of 227 patients with 809 follow-up (18)F-FDG PET/CT scans reviewed were found to have incidental brain metastases. The mean age of the patients with incidental brain metastasis was 68 y (range, 60-77 y). The mean time from initial diagnosis to time of detection of incidental brain metastasis was 36 mo (range, 15-66 mo). When MRI was used as the gold standard, our false-positive rate was zero. Conclusion: By including the entire head during follow-up (18)F-FDG PET/CT scans of patients with non-small cell lung cancer, brain metastases can be detected earlier while still asymptomatic. But, given the additional scan time, radiation, and low incidence of new brain metastases in asymptomatic patients, the cost-to-benefit ratio should be weighed by each institution. © 2017 by the

  9. Conflict Processing in the Rat Brain: Behavioral Analysis and Functional μPET Imaging Using [F]Fluorodeoxyglucose.

    PubMed

    Marx, Christine; Lex, Björn; Calaminus, Carsten; Hauber, Wolfgang; Backes, Heiko; Neumaier, Bernd; Mies, Günter; Graf, Rudolf; Endepols, Heike

    2012-01-01

    Conflicts in spatial stimulus-response tasks occur when the task-relevant feature of a stimulus implies a response toward a certain location which does not match the location of stimulus presentation. This conflict leads to increased error rates and longer reaction times, which has been termed Simon effect. A model of dual route processing (automatic and intentional) of stimulus features has been proposed, predicting response conflicts if the two routes are incongruent. Although there is evidence that the prefrontal cortex, notably the anterior cingulate cortex (ACC), plays a crucial role in conflict processing, the neuronal basis of dual route architecture is still unknown. In this study, we pursue a novel approach using positron emission tomography (PET) to identify relevant brain areas in a rat model of an auditory Simon task, a neuropsychological interference task, which is commonly used to study conflict processing in humans. For combination with PET we used the metabolic tracer [(18)F]fluorodeoxyglucose, which accumulates in metabolically active brain cells during the behavioral task. Brain areas involved in conflict processing are supposed to be activated when automatic and intentional route processing lead to different responses (dual route model). Analysis of PET data revealed specific activation patterns for different task settings applicable to the dual route model as established for response conflict processing. The rat motor cortex (M1) may be part of the automatic route or involved in its facilitation, while premotor (M2), prelimbic, and ACC seemed to be essential for inhibiting the incorrect, automatic response, indicating conflict monitoring functions. Our findings and the remarkable similarities to the pattern of activated regions reported during conflict processing in humans demonstrate that our rodent model opens novel opportunities to investigate the anatomical basis of conflict processing and dual route architecture.

  10. O-(2-18F-fluoroethyl)-L-tyrosine PET for evaluation of brain metastasis recurrence after radiotherapy: an effectiveness and cost-effectiveness analysis.

    PubMed

    Heinzel, Alexander; Müller, Dirk; Yekta-Michael, Sareh Said; Ceccon, Garry; Langen, Karl-Josef; Mottaghy, Felix M; Wiesmann, Martin; Kocher, Martin; Hattingen, Elke; Galldiks, Norbert

    2017-09-01

    Conventional MRI is the standard method to diagnose recurrence of brain metastases after radiation. However, following radiation therapy, reactive transient blood-brain barrier alterations with consecutive contrast enhancement can mimic brain metastasis recurrence. Recent studies have suggested that O-(2-18F-fluoroethyl)-L-tyrosine (FET) PET improves the correct differentiation of brain metastasis recurrence from radiation injury. Based on published evidence and clinical expert opinion, we analyzed effectiveness and cost-effectiveness of the use of FET PET in addition to MRI compared with MRI alone for the diagnosis of recurrent brain metastases. A decision-tree model was designed to compare the 2 diagnostic strategies from the perspective of the German Statutory Health Insurance (SHI) system. Effectiveness was defined as correct diagnosis of recurrent brain metastasis and was compared between FET PET with MRI and MRI alone. Costs were calculated for a baseline scenario and for a more expensive scenario. Robustness of the results was tested using sensitivity analyses. Compared with MRI alone, FET PET in combination with MRI increases the rate of correct diagnoses by 42% (number needed to diagnose of 3) with an incremental cost-effectiveness ratio of €2821 (baseline scenario) and €4014 (more expensive scenario) per correct diagnosis. The sensitivity analyses confirmed the robustness of the results. The model suggests that the additional use of FET PET with conventional MRI for the diagnosis of recurrent brain metastases may be cost-effective. Integration of FET PET has the potential to avoid overtreatment with corresponding costs as well as unnecessary side effects.

  11. Implementation and evaluation of a calculated attenuation correction for PET

    SciTech Connect

    Siegel, S.; Dahlbom, M. . Dept. of Radiological Sciences)

    1992-08-01

    A limiting factor in PET is the necessity of a transmission scan for attenuation correction (AC). In areas of uniform attenuation, this measured AC can be replaced by a calculated AC. This paper presents an accurate and efficient method based on estimating the object contour from the emission sinograms. The method relies on a robust algorithm to determine the border between activity and scatter background. In this work, the authors present an algorithm that has been consistent in finding the object outline for a variety of tracers ([sup 18]F-FDG, [sup 18]F-FDOPA, [sup 15]O-water and [sup 13]N-ammonia), extreme uptake distributions (brain tumors and hemispherectomies) and system geometries, with little operator intervention. FDG brain scans using this algorithm were compared to images corrected using measured AC, showing a maximum deviation of [plus minus] 8.9%. The algorithm has been extended to abdominal PET scans and 3-D acquisitions.

  12. Design considerations for a C-shaped PET system, dedicated to small animal brain imaging, using GATE Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Efthimiou, N.; Papadimitroulas, P.; Kostou, T.; Loudos, G.

    2015-09-01

    Commercial clinical and preclinical PET scanners rely on the full cylindrical geometry for whole body scans as well as for dedicated organs. In this study we propose the construction of a low cost dual-head C-shaped PET system dedicated for small animal brain imaging. Monte Carlo simulation studies were performed using GATE toolkit to evaluate the optimum design in terms of sensitivity, distortions in the FOV and spatial resolution. The PET model is based on SiPMs and BGO pixelated arrays. Four different configurations with C- angle 0°, 15°, 30° and 45° within the modules, were considered. Geometrical phantoms were used for the evaluation process. STIR software, extended by an efficient multi-threaded ray tracing technique, was used for the image reconstruction. The algorithm automatically adjusts the size of the FOV according to the shape of the detector's geometry. The results showed improvement in sensitivity of ∼15% in case of 45° C-angle compared to the 0° case. The spatial resolution was found 2 mm for 45° C-angle.

  13. P-glycoprotein Function in the Rodent Brain Displays a Daily Rhythm, a Quantitative In Vivo PET Study.

    PubMed

    Savolainen, Heli; Meerlo, Peter; Elsinga, Philip H; Windhorst, Albert D; Dierckx, Rudi A J O; Colabufo, Nicola A; van Waarde, Aren; Luurtsema, Gert

    2016-11-01

    The blood-brain barrier (BBB) contributes to brain homeostasis by protecting the brain from harmful compounds. P-glycoprotein (P-gp) is one of the major efflux transporters at the BBB. In the present study, we assessed whether (1) P-gp function in the brain is constant or fluctuates across the day and (2) if it is affected by sleep deprivation. Four groups of rats were PET scanned with a radiolabeled P-gp substrate [(18)F]MC225, each at a different moment of the 12-h light-dark cycle to study diurnal variations: early sleep phase (ZT3), late sleep phase (ZT9), early active phase (ZT15), and late active phase (ZT21). In two additional groups, controls were allowed to sleep normally while experimental animals were sleep-deprived for 10 h in a slowly rotating drum during the sleep phase. Kinetic modeling with a one-tissue compartment model fit resulted for all brain regions in 1.2-1.8-fold higher distribution volumes (V T ) at ZT15 than at other time points. V T -values at ZT3, ZT9, and ZT21 were not significantly different from each other. Regional tracer distribution volumes in controls and sleep-deprived animals were also not significantly different. Our results indicate that P-gp function in rats displays a daily rhythm with reduced function at the beginning of the active phase. This rhythm is not dependent on sleep since acute sleep deprivation had no effect. Knowing the diurnal variation of P-gp function could be important for the design of PET studies and for choosing the correct administration time for P-gp-dependent drugs.

  14. Gender differences in healthy aging and Alzheimer's Dementia: A (18) F-FDG-PET study of brain and cognitive reserve.

    PubMed

    Malpetti, Maura; Ballarini, Tommaso; Presotto, Luca; Garibotto, Valentina; Tettamanti, Marco; Perani, Daniela

    2017-08-01

    Cognitive reserve (CR) and brain reserve (BR) are protective factors against age-associated cognitive decline and neurodegenerative disorders. Very limited evidence exists about gender effects on brain aging and on the effect of CR on brain modulation in healthy aging and Alzheimer's Dementia (AD). We investigated gender differences in brain metabolic activity and resting-state network connectivity, as measured by (18) F-FDG-PET, in healthy aging and AD, also considering the effects of education and occupation. The clinical and imaging data were retrieved from large datasets of healthy elderly subjects (HE) (225) and AD patients (282). In HE, males showed more extended age-related reduction of brain metabolism than females in frontal medial cortex. We also found differences in brain modulation as metabolic increases induced by education and occupation, namely in posterior associative cortices in HE males and in the anterior limbic-affective and executive networks in HE females. In AD patients, the correlations between education and occupation levels and brain hypometabolism showed gender differences, namely a posterior temporo-parietal association in males and a frontal and limbic association in females, indicating the involvement of different networks. Finally, the metabolic connectivity in both HE and AD aligned with these results, suggesting greater efficiency in the posterior default mode network for males, and in the anterior frontal executive network for females. The basis of these brain gender differences in both aging and AD, obtained exploring cerebral metabolism, metabolic connectivity and the effects of education and occupation, is likely at the intersection between biological and sociodemographic factors. Hum Brain Mapp 38:4212-4227, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  15. PET measurement of C-11-methylphenidate pharmacokinetics and distribution in the human brain

    SciTech Connect

    Ding, Y.S.; Fowler, J.S.; Wang, G.J.

    1994-05-01

    Methylphenidate (MP), a psychostimulant drug which binds to the dopamine transporter (DAT), is the most commonly prescribed psychotropic medication for children in the USA yet little is known about its pharmacokinetics and distribution in the human brain. PET was used to measure the pharmacokinetics of d,l-threo-[{sup 11}C]methylphenidate (MP*) the labelled form of the prescribed drug (ritalin) in eight normal male subjects (age range 20-74 years). Four subjects had 2 repeated scans to assess test/retest reproducibility and 4 had one wan as baseline and the second 10 minutes after administration of 0.5 mg/kg MP to assess specific to nonspecific binding. Dynamic scans were started immediately after injection of MP*(5-10 mCi) for 90 min on the CTI-931 (6 x 6 x 6.5 mm FWHM). Time activity curves for tissue concentration and for unchanged tracer in plasma were used to calculate the distribution volume (DV) in basal ganglia (BG), cerebellum (CB) and global (GL) regions using graphical analysis. Binding of MP* was highest in the BG (0.008% dose/cc) uptake in CB corresponded to (0.006) and in GL to (0.005). Kinetic analysis revealed fast uptake of MP* with peak uptake in BG occurring 5-20 min PI, and in CB and GL at 5-13 min PI. Half time clearance for MP* occurred 90 min PI for BG and 60 min for CB and GL. Test/retest variability was <10% (range -0.5 to +7.0% for the DV ratio (BG/CB)). Pretreatment with MP selectively reduced uptake in BG wherein it did not affect uptake in CB or GL. The ratio of the DV in BG to that in CB changed from 2.12{plus_minus}0.1 to 1.35{plus_minus}0.04. The lack of an effect of MP in CB an area with a high density of norepinephrine (NE) transporters suggests that MP* is not binding to the NE transporter.

  16. Non-invasive PET imaging of brain inflammation at disease onset predicts spontaneous recurrent seizures and reflects comorbidities.

    PubMed

    Bertoglio, Daniele; Verhaeghe, Jeroen; Santermans, Eva; Amhaoul, Halima; Jonckers, Elisabeth; Wyffels, Leonie; Van Der Linden, Annemie; Hens, Niel; Staelens, Steven; Dedeurwaerdere, Stefanie

    2017-03-01

    Brain inflammation is an important factor in the conversion of a healthy brain into an epileptic one, a phenomenon known as epileptogenesis, offering a new entry point for prognostic tools. The development of anti-epileptogenic therapies to treat before or at disease onset is hampered by our inability to predict the severity of the disease outcome. In a rat model of temporal lobe epilepsy we aimed to assess whether in vivo non-invasive imaging of brain inflammation at disease onset was predictive of spontaneous recurrent seizures (SRS) frequency and severity of depression-like and sensorimotor-related comorbidities. To this end, translocator protein, a biomarker of inflammation, was imaged by means of positron emission tomography (PET) 2 and 4weeks post-status epilepticus using [(18)F]-PBR111. Translocator protein was highly upregulated 2weeks post-status epilepticus in limbic structures (up to 2.1-fold increase compared to controls in temporal lobe, P<0.001), whereas 4weeks post-status epilepticus, upregulation decreased (up to 1.6-fold increase compared to controls in temporal lobe, P<0.01) and was only apparent in a subset of these regions. Animals were monitored with video-electroencephalography during all stages of disease (acute, latent - first seizures appearing around 2weeks post-status epilepticus - and chronic phases), for a total of 12weeks, in order to determine SRS frequency for each subject (range 0.00-0.83SRS/day). We found that regional PET uptake at 2 and 4weeks post-status epilepticus correlated with the severity of depression-like and sensorimotor-related comorbidities during chronic epilepsy (P<0.05 for each test). Regional PET imaging did not correlate with SRS frequency, however, by applying a multivariate data-driven modeling approach based on translocator protein PET imaging at 2weeks post-status epilepticus, we accurately predicted the frequency of SRS (R=0.92; R(2)=0.86; P<0.0001) at the onset of epilepsy. This study not only demonstrates

  17. Anatomy-guided brain PET imaging incorporating a joint prior model

    NASA Astrophysics Data System (ADS)

    Lu, Lijun; Ma, Jianhua; Feng, Qianjin; Chen, Wufan; Rahmim, Arman

    2015-03-01

    We proposed a maximum a posterior (MAP) framework for incorporating information from co-registered anatomical images into PET image reconstruction through a novel anato-functional joint prior. The characteristic of the utilized hyperbolic potential function is determinate by the voxel intensity differences within the anatomical image, while the penalization is computed based on voxel intensity differences in reconstructed PET images. Using realistic simulated 18FDG PET scan data, we optimized the performance of the proposed MAP reconstruction with the joint prior (JP-MAP) and compared its performance with conventional 3D MLEM and 3D MAP reconstructions. The proposed JP-MAP reconstruction algorithm resulted in quantitatively enhanced reconstructed images, as demonstrated in extensive FDG PET simulation study. The proposed method was also tested on a 20 min Florbetapir patient study performed on the high-resolution research tomograph. It was shown to outperform conventional methods in visual as well as quantitative accuracy assessment (in terms of regional noise versus activity value performance). The JP-MAP method was also compared with another MR-guided MAP reconstruction method, utilizing the Bowsher prior and was seen to result in some quantitative enhancements, especially in the case of MR-PET mis-registrations, and a definitive improvement in computational performance.

  18. Evaluation of a potential generator-produced PET tracer for cerebral perfusion imaging: single-pass cerebral extraction measurements and imaging with radiolabeled Cu-PTSM.

    PubMed

    Mathias, C J; Welch, M J; Raichle, M E; Mintun, M A; Lich, L L; McGuire, A H; Zinn, K R; John, E K; Green, M A

    1990-03-01

    Copper(II) pyruvaldehyde bis(N4-methylthiosemicarbazone) (Cu-PTSM), copper(II) pyruvaldehyde bis(N4-dimethylthiosemicarbazone) (Cu-PTSM2), and copper(II) ethylglyoxal bis(N4-methylthiosemicarbazone) (Cu-ETSM), have been proposed as PET tracers for cerebral blood flow (CBF) when labeled with generator-produced 62Cu (t1/2 = 9.7 min). To evaluate the potential of Cu-PTSM for CBF PET studies, baboon single-pass cerebral extraction measurements and PET imaging were carried out with the use of 67Cu (t1/2 = 2.6 days) and 64Cu (t1/2 = 12.7 hr), respectively. All three chelates were extracted into the brain with high efficiency. There was some clearance of all chelates in the 10-50-sec time frame and Cu-PTSM2 continued to clear. Cu-PTSM and Cu-ETSM have high residual brain activity. PET imaging of baboon brain was carried out with the use of [64Cu]-Cu-PTSM. For comparison with the 64Cu brain image, a CBF (15O-labeled water) image (40 sec) was first obtained. Qualitatively, the H2(15)O and [64Cu]-Cu-PTSM images were very similar; for example, a comparison of gray to white matter uptake resulted in ratios of 2.42 for H2(15)O and 2.67 for Cu-PTSM. No redistribution of 64Cu was observed in 2 hr of imaging, as was predicted from the single-pass study results. Quantitative determination of blood flow using Cu-PTSM showed good agreement with blood flow determined with H2(15)O. This data suggests that [62Cu]-Cu-PTSM may be a useful generator-produced radiopharmaceutical for blood flow studies with PET.

  19. Possible role of an error detection mechanism in brain processing of deception: PET-fMRI study.

    PubMed

    Kireev, Maxim; Korotkov, Alexander; Medvedeva, Natalia; Medvedev, Svyatoslav

    2013-12-01

    To investigate brain maintenance of deliberate deception the positron emission tomography and the event related functional MRI studies were performed. We used an experimental paradigm that presupposed free choices between equally beneficial deceptive or honest actions. Experimental task simulated the "Cheat" card game which aims to defeat an opponent by sequential deceptive and honest claims. Results of both the PET and the fMRI studies revealed that execution of both deliberately deceptive and honest claims is associated with fronto-parietal brain network comprised of inferior and middle frontal gyri, precentral gyrus (BA 6), caudate nucleus, and inferior parietal lobule. Direct comparison between those claims, balanced in terms of decision making and action outcome (gain and losses), revealed activation of areas specifically associated with deception execution: precentral gyrus (BA 6), caudate nuclei, thalamus and inferior parietal lobule (BA 39/40). The obtained experimental data were discussed in relation to a possible role of an error detection system in processing deliberate deception.

  20. Brain 18F-FDG-PET characteristics in patients with paraneoplastic neurological syndrome and its correlation with clinical and MRI findings.

    PubMed

    Masangkay, Neil; Basu, Sandip; Moghbel, Mateen; Kwee, Thomas; Alavi, Abass

    2014-10-01

    This study aimed to examine the imaging characteristics and clinical and MRI correlates of brain F-fluorodeoxyglucose (F-FDG)-PET imaging in patients with paraneoplatic neurological syndrome. Data of patients diagnosed with paraneoplastic neurological syndrome were retrospectively reviewed using the electronic medical records of the patients, looking specifically at records of hospital stays, laboratory findings and imaging reports. Both brain MRI and F-FDG-PET imaging characteristics were analyzed and compared. A total of 19 patients (ages 26-78; 13 female and six male patients) with clinical diagnoses of PNS were analyzed in this study. Limbic encephalitis (paraneoplastic limbic encephalitis) was found in 10 patients, seven of whom had a diagnosis of cancer. Brain F-FDG-PET showed bilaterally increased mesial temporal F-FDG uptake in eight of 10 patients with limbic encephalitis; seven of these eight patients exhibited memory loss. There was also a notable reduction in general cortical F-FDG uptake (including in the primary visual cortex) in six of the 10 patients with limbic encephalitis; three of the six patients had their primary motor cortices spared, two of them being spared bilaterally. Five of the seven limbic encephalitis patients with diagnosed cancer and two of the three without it had the aforementioned cortical and temporal lobe findings. Of the eight patients with onconeuronal antibodies, seven had temporal lobe enhancement and a total of six had diffuse cortical dysfunction. One patient with paraneoplastic limbic encephalitis without antibodies had demonstrated severely increased F-FDG uptake in both occipital lobes extending to the temporal lobes. The other patient without antibodies had a normal PET scan. Only one patient among four with paraneoplastic cerebellar degeneration had demonstrated decreased cerebellar uptake on F-FDG-PET that correlated with atrophy of the cerebellar vermis on MRI. Three patients had a clinical diagnosis of sensory

  1. Quantitative characterization of brain β-amyloid using a joint PiB/FDG PET image histogram

    NASA Astrophysics Data System (ADS)

    Camp, Jon J.; Hanson, Dennis P.; Holmes, David R.; Kemp, Bradley J.; Senjem, Matthew L.; Murray, Melissa E.; Dickson, Dennis W.; Parisi, Joseph; Petersen, Ronald C.; Lowe, Val J.; Robb, Richard A.

    2014-03-01

    A complex analysis performed by spatial registration of PiB and MRI patient images in order to localize the PiB signal to specific cortical brain regions has been proven effective in identifying imaging characteristics associated with underlying Alzheimer's Disease (AD) and Lewy Body Disease (LBD) pathology. This paper presents an original method of image analysis and stratification of amyloid-related brain disease based on the global spatial correlation of PiB PET images with 18F-FDG PET images (without MR images) to categorize the PiB signal arising from the cortex. Rigid registration of PiB and 18F-FDG images is relatively straightforward, and in registration the 18F-FDG signal serves to identify the cortical region in which the PiB signal is relevant. Cortical grey matter demonstrates the highest levels of amyloid accumulation and therefore the greatest PiB signal related to amyloid pathology. The highest intensity voxels in the 18F-FDG image are attributed to the cortical grey matter. The correlation of the highest intensity PiB voxels with the highest 18F-FDG values indicates the presence of β-amyloid protein in the cortex in disease states, while correlation of the highest intensity PiB voxels with mid-range 18F-FDG values indicates only nonspecific binding in the white matter.

  2. Designing Image Operators for MRI-PET Image Fusion of the Brain

    SciTech Connect

    Marquez, Jorge; Gastelum, Alfonso; Padilla, Miguel A.

    2006-09-08

    Our goal is to obtain images combining in a useful and precise way the information from 3D volumes of medical imaging sets. We address two modalities combining anatomy (Magnetic Resonance Imaging or MRI) and functional information (Positron Emission Tomography or PET). Commercial imaging software offers image fusion tools based on fixed blending or color-channel combination of two modalities, and color Look-Up Tables (LUTs), without considering the anatomical and functional character of the image features. We used a sensible approach for image fusion taking advantage mainly from the HSL (Hue, Saturation and Luminosity) color space, in order to enhance the fusion results. We further tested operators for gradient and contour extraction to enhance anatomical details, plus other spatial-domain filters for functional features corresponding to wide point-spread-function responses in PET images. A set of image-fusion operators was formulated and tested on PET and MRI acquisitions.

  3. Search for PET probes for imaging the globus pallidus studied with rat brain ex vivo autoradiography.

    PubMed

    Ishiwata, K; Ogi, N; Shimada, J; Wang, W; Ishii, K; Tanaka, A; Suzuki, F; Senda, M

    2000-12-01

    We have evaluated the feasibility of using four positron emission tomography (PET) tracers for imaging the globus pallidus by ex vivo autoradiography in rats. The tracers investigated were [11C]KF18446, [11C]SCH 23390 and [11C]raclopride for mapping adenosine A2A, dopamine D1 and dopamine D2 receptors, respectively, and [18F]FDG. The highest uptake by the globus pallidus was found for [11C]SCH 23390, followed by [18F]FDG, [11C]KF18446 and [11C]raclopride. The receptor-specific uptake by the globus pallidus was observed in [11C]KF18446 and [11C]SCH 23390, but not in [11C]raclopride. Uptake ratios of globus pallidus to the striatum for [18F]FDG and [11C]KF18446 were approximately 0.6, which was twice as large as that for [11C]SCH 23390. In a rat model of degeneration of striatopallidal gamma-aminobutyric acid-ergic-enkephalin neurons induced by intrastriatal injection of quinolinic acid, the uptake of [11C]KF18446 by the striatum and globus pallidus was remarkably reduced. To prove the visualization of the globus pallidus by PET with [18F]FDG and [11C]KF18446, PET-MRI registration technique and advances in PET technologies providing high-resolution PET scanner will be required. The metabolic activity of the globus pallidus could then be measured by PET with [18F]FDG, and [11C]KF18446 may be a candidate tracer for imaging the pallidal terminals projecting from the striatum.

  4. 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.

    PubMed

    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 SUVmean 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 SUVmean 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

  5. Characterization and performance of monolithic detector blocks with a dedicated ASIC front-end readout for PET imaging of the human brain

    NASA Astrophysics Data System (ADS)

    Rato Mendes, Pedro; Sarasola Martín, Icíar; Cañadas, Mario; de Acilu, Paz García; Cuypers, Robin; Manuel Pérez, José; Willmott, Carlos

    2011-05-01

    We are developing a human brain PET scanner prototype compatible with MRI based on monolithic scintillator crystals, APD matrices and a dedicated ASIC front-end readout. In this work we report on the performance of individual detector modules and on the operation of such modules in PET coincidence. Results will be presented on the individual characterization of detector blocks and its ASIC front-end readout, with measured energy resolutions of 13% full-width half-maximum (FWHM) at 511 keV and spatial resolutions of the order of 2 mm FWHM. First results on PET coincidence performance indicate spatial resolutions as good as 2.1 mm FWHM for SSRB/FBP reconstruction of tomographic data obtained using a simple PET demonstrator based on a pair of monolithic detector blocks with ASIC readout.

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

    PubMed

    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 < 0.01), the relative signal 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.

  7. FDG-PET in the selection of brain lesions for biopsy

    SciTech Connect

    Hanson, M.W.; Glantz, M.J.; Hoffman, J.M.; Friedman, A.H.; Burger, P.C.; Schold, S.C.; Coleman, R.E. )

    1991-09-01

    The CT-guided stereotaxic needle biopsy has become a widely used procedure in the diagnostic evaluation of intracranial lesions including tumors. Conventional CT or MR frequently defines the anatomic regions of abnormality, which may be multiple lesions or a single lesion that is heterogeneous in cellular composition owing to the topographic variation of cellular constituency or the combination of active disease, nonspecific inflammation, necrosis, and/or edema. In these cases, selection of the most appropriate site for a successful diagnostic needle biopsy can be difficult. In three patients, we have used (18F)fluorodeoxyglucose (FDG) positron emission tomography (PET) to determine the site most likely to provide a diagnostic biopsy result. In the first patient, who presented with confusion, multiple biopsies from the temporal lobe, based on MR abnormalities, revealed only reactive gliosis and edema. Repeat biopsy directed by PET revealed an anaplastic astrocytoma. In a second patient, PET allowed us to differentiate radiation effect from active metastatic breast cancer. In the third patient, who presented with a grand mal seizure, biopsy of a CT-defined hypodense region demonstrated lymphocytosis. Metabolism of FDG was normal or increased in areas of Aspergillus encephalitis at autopsy. These preliminary studies suggest a complementary role for FDG-PET and CT or MR in selected patients for defining the intracranial site most likely to yield a positive biopsy result.

  8. Real-time 3D motion tracking for small animal brain PET

    NASA Astrophysics Data System (ADS)

    Kyme, A. Z.; Zhou, V. W.; Meikle, S. R.; Fulton, R. R.

    2008-05-01

    High-resolution positron emission tomography (PET) imaging of conscious, unrestrained laboratory animals presents many challenges. Some form of motion correction will normally be necessary to avoid motion artefacts in the reconstruction. The aim of the current work was to develop and evaluate a motion tracking system potentially suitable for use in small animal PET. This system is based on the commercially available stereo-optical MicronTracker S60 which we have integrated with a Siemens Focus-220 microPET scanner. We present measured performance limits of the tracker and the technical details of our implementation, including calibration and synchronization of the system. A phantom study demonstrating motion tracking and correction was also performed. The system can be calibrated with sub-millimetre accuracy, and small lightweight markers can be constructed to provide accurate 3D motion data. A marked reduction in motion artefacts was demonstrated in the phantom study. The techniques and results described here represent a step towards a practical method for rigid-body motion correction in small animal PET. There is scope to achieve further improvements in the accuracy of synchronization and pose measurements in future work.

  9. Brain FDG-PET changes in ALS and ALS-FTD.

    PubMed

    Renard, Dimitri; Collombier, Laurent; Castelnovo, Giovanni; Fourcade, Genevieve; Kotzki, Pierre-Olivier; LaBauge, Pierre

    2011-12-01

    FDG-PET in ALS most typically demonstrates a primary (and sometimes also supplementary) motor cortex hypometabolism, often associated with more diffuse cortical hypometabolism involving mostly the dorsolateral prefrontal cortex, the medial and lateral premotor cortices, and the bilateral insular cortex involvement. In ALS-FTD, extensive temporal hypometabolism is seen in addition to severe diffuse frontal hypometabolism. This study analyses FDG-PET findings in 6 ALS patients and 4 ALS-FTD patients. In addition to earlier described areas of hypometabolism in ALS, we found also reduced FDG-PET metabolism in the medial frontal cortex, the orbitofrontal cortex, and the anterior temporal lobe in our ALS patients. The anterolateral area was the best preserved part of the frontal lobe in ALS patients. In ALS-FTD, frontal and temporal hypometabolism was severe (and parietal hypometabolism was often also present) with relatively preserved perirolandic metabolism. In ALS, more diffuse frontal and temporal FDG-PET hypometabolism was seen than earlier reported, with the anterolateral area as the best preserved part of the frontal lobe. In ALS-FTD, relatively preserved perirolandic metabolism was seen, associated with severe frontal and temporal hypometabolism.

  10. ROC (Receiver Operating Characteristics) study of maximum likelihood estimator human brain image reconstructions in PET (Positron Emission Tomography) clinical practice

    SciTech Connect

    Llacer, J.; Veklerov, E.; Nolan, D. ); Grafton, S.T.; Mazziotta, J.C.; Hawkins, R.A.; Hoh, C.K.; Hoffman, E.J. )

    1990-10-01

    This paper will report on the progress to date in carrying out Receiver Operating Characteristics (ROC) studies comparing Maximum Likelihood Estimator (MLE) and Filtered Backprojection (FBP) reconstructions of normal and abnormal human brain PET data in a clinical setting. A previous statistical study of reconstructions of the Hoffman brain phantom with real data indicated that the pixel-to-pixel standard deviation in feasible MLE images is approximately proportional to the square root of the number of counts in a region, as opposed to a standard deviation which is high and largely independent of the number of counts in FBP. A preliminary ROC study carried out with 10 non-medical observers performing a relatively simple detectability task indicates that, for the majority of observers, lower standard deviation translates itself into a statistically significant detectability advantage in MLE reconstructions. The initial results of ongoing tests with four experienced neurologists/nuclear medicine physicians are presented. Normal cases of {sup 18}F -- fluorodeoxyglucose (FDG) cerebral metabolism studies and abnormal cases in which a variety of lesions have been introduced into normal data sets have been evaluated. We report on the results of reading the reconstructions of 90 data sets, each corresponding to a single brain slice. It has become apparent that the design of the study based on reading single brain slices is too insensitive and we propose a variation based on reading three consecutive slices at a time, rating only the center slice. 9 refs., 2 figs., 1 tab.

  11. Stereotaxic (18)F-FDG PET and MRI templates with three-dimensional digital atlas for statistical parametric mapping analysis of tree shrew brain.

    PubMed

    Huang, Qi; Nie, Binbin; Ma, Chen; Wang, Jing; Zhang, Tianhao; Duan, Shaofeng; Wu, Shang; Liang, Shengxiang; Li, Panlong; Liu, Hua; Sun, Hua; Zhou, Jiangning; Xu, Lin; Shan, Baoci

    2017-09-14

    Tree shrews are proposed as an alternative animal model to nonhuman primates due to their close affinity to primates. Neuroimaging techniques are widely used to study brain functions and structures of humans and animals. However, tree shrews are rarely applied in neuroimaging field partly due to the lack of available species specific analysis methods. In this study, 10 PET/CT and 10 MRI images of tree shrew brain were used to construct PET and MRI templates; based on histological atlas we reconstructed a three-dimensional digital atlas with 628 structures delineated; then the digital atlas and templates were aligned into a stereotaxic space. Finally, we integrated the digital atlas and templates into a toolbox for tree shrew brain spatial normalization, statistical analysis and results localization. We validated the feasibility of the toolbox by simulated data with lesions in laterodorsal thalamic nucleus (LD). The lesion volumes of simulated PET and MRI images were (12.97±3.91)mm(3) and (7.04±0.84)mm(3). Statistical results at p<0.005 showed the lesion volumes of PET and MRI were 13.18mm(3) and 8.06mm(3) in LD. To our knowledge, we report the first PET template and digital atlas of tree shrew brain. Compared to the existing MRI templates, our MRI template was aligned into stereotaxic space. And the toolbox is the first software dedicated for tree shrew brain analysis. The templates and digital atlas of tree shrew brain, as well as the toolbox, facilitate the use of tree shrews in neuroimaging field. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Effects of MK-801 treatment across several pre-clinical analyses including a novel assessment of brain metabolic function utilizing PET and CT fused imaging in live rats.

    PubMed

    Daya, R P; Bhandari, J K; Hui, P A; Tian, Y; Farncombe, T; Mishra, R K

    2014-02-01

    Functional imaging studies in schizophrenic patients have demonstrated metabolic brain abnormalities during cognitive tasks. This study aimed to 1) introduce a novel analysis of brain metabolic function in live animals to characterize the hypo- and hyperfrontality phenomena observed in schizophrenia and following NMDA antagonist exposure, and 2) identify a robust and representative MK-801 treatment regimen that effectively models brain metabolic abnormalities as well as a range of established behavioural abnormalities representative of schizophrenia. The validity of the MK-801 animal model was examined across several established pre-clinical tests, and a novel assessment of brain metabolic function using PET/CT fused imaging. In the present study, MK-801 was administered acutely at 0.1 mg/kg and 0.5 mg/kg, and sub-chronically at 0.5 mg/kg daily for 7 days. Acute treatment at 0.5 mg/kg-disrupted facets of memory measured through performance in the 8-arm radial maze task and generated abnormalities in sensorimotor gating, social interaction and locomotor activity. Furthermore, this treatment regimen induced hyperfrontality (increased brain metabolic function in the prefrontal area) observed via PET/CT fused imaging in the live rat. While PET and CT fused imaging in the live rat offers a functional representation of metabolic function, more advanced PET/CT integration is required to analyze more discrete brain regions. These findings provide insight on the effectiveness of the MK-801 pre-clinical model of schizophrenia and provide an optimal regimen to model schizophrenia. PET/CT fused imaging offers a highly translatable tool to assess hypo- and hyperfrontality in live animals. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

    PubMed

    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

  14. Current status of PET imaging in Huntington's disease.

    PubMed

    Pagano, Gennaro; Niccolini, Flavia; Politis, Marios

    2016-06-01

    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]H2O), 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 in HD.

  15. [Influence of photon scattering on the quantification of relative changes in longitudinal brain PET studies with 18F-FDG].

    PubMed

    Aguiar Fernández, P; Falcón Falcón, C; Crespo Vázquez, C; Cot Sanz, A; Lomeña Caballero, F; Pavía Segura, J; Ros Puig, D

    2005-01-01

    To study the effect of photon scattering on the quantification of relative changes of 18F-FDG uptake in longitudinal brain PET studies. Two studies from a numerical Zubal phantom were simulated. One of these was a basal reference study and the other was an activated study showing an increase or decrease in the uptake in a region of the anterior cingulated cortex. SimSET Monte Carlo code was used to simulate PET sinograms. Primary photons, which did not undergo interactions, and scattered photons, which underwent one or more interactions, were stored in separate files to assess the effect of scattering. Reconstruction was carried out using an iterative algorithm based on ordered subsets of projections (OSEM-2D). The relative changes in uptake were calculated from images reconstructed with all the photons (primary and scattered) and from images reconstructed with only primary photons. A linear relationship between the calculated and theoretical values was obtained both for the images reconstructed with all the photons and for those reconstructed with primary photons. Our findings show a relative change recovery of 79% +/- 0.4% for all photons and 91% +/- 0.5% for primary photons only. Our results highlight subestimation of relative changes of 12% +/- 0.7% when scattered photons are used. Thus the importance of correcting this degradation in order to improve quantification is shown.

  16. [11C]5-HTP and microPET are not suitable for pharmacodynamic studies in the rodent brain

    PubMed Central

    Visser, Anniek KD; Ramakrishnan, Nisha K; Willemsen, Antoon TM; Di Gialleonardo, Valentina; de Vries, Erik FJ; Kema, Ido P; Dierckx, Rudi AJO; van Waarde, Aren

    2014-01-01

    The PET tracer [11C]5-hydroxytryptophan ([11C]5-HTP), which is converted to [11C]5-hydroxytryptamine ([11C]5-HT) by aromatic amino acid decarboxylase (AADC), is thought to measure 5-HT synthesis rates. But can we measure these synthesis rates by kinetic modeling of [11C]5-HTP in rat? Male rats were scanned with [11C]5-HTP (60 minutes) after different treatments. Scans included arterial blood sampling and metabolite analysis. 5-HT synthesis rates were calculated by a two-tissue compartment model (2TCM) with irreversible tracer trapping or Patlak analysis. Carbidopa (inhibitor peripheral AADC) dose-dependently increased [11C]5-HTP brain uptake, but did not influence 2TCM parameters. Therefore, 10 mg/kg carbidopa was applied in all subsequent study groups. These groups included treatment with NSD 1015 (general AADC inhibitor) or p-chlorophenylalanine (PCPA, inhibitor of tryptophan hydroxylase, TPH). In addition, the effect of a low-tryptophan (Trp) diet was investigated. NSD 1015 or Trp depletion did not affect any model parameters, but PCPA reduced [11C]5-HTP uptake, and the k3. This was unexpected as NSD 1015 directly inhibits the enzyme converting [11C]5-HTP to [11C]5-HT, suggesting that trapping of radioactivity does not distinguish between parent tracer and its metabolites. As different results have been acquired in monkeys and humans, [11C]5-HTP-PET may be suitable for measuring 5-HT synthesis in primates, but not in rodents. PMID:24084697

  17. [(11)C]5-HTP and microPET are not suitable for pharmacodynamic studies in the rodent brain.

    PubMed

    Visser, Anniek K D; Ramakrishnan, Nisha K; Willemsen, Antoon T M; Di Gialleonardo, Valentina; de Vries, Erik F J; Kema, Ido P; Dierckx, Rudi A J O; van Waarde, Aren

    2014-01-01

    The PET tracer [(11)C]5-hydroxytryptophan ([(11)C]5-HTP), which is converted to [(11)C]5-hydroxytryptamine ([(11)C]5-HT) by aromatic amino acid decarboxylase (AADC), is thought to measure 5-HT synthesis rates. But can we measure these synthesis rates by kinetic modeling of [(11)C]5-HTP in rat? Male rats were scanned with [(11)C]5-HTP (60 minutes) after different treatments. Scans included arterial blood sampling and metabolite analysis. 5-HT synthesis rates were calculated by a two-tissue compartment model (2TCM) with irreversible tracer trapping or Patlak analysis. Carbidopa (inhibitor peripheral AADC) dose-dependently increased [(11)C]5-HTP brain uptake, but did not influence 2TCM parameters. Therefore, 10 mg/kg carbidopa was applied in all subsequent study groups. These groups included treatment with NSD 1015 (general AADC inhibitor) or p-chlorophenylalanine (PCPA, inhibitor of tryptophan hydroxylase, TPH). In addition, the effect of a low-tryptophan (Trp) diet was investigated. NSD 1015 or Trp depletion did not affect any model parameters, but PCPA reduced [(11)C]5-HTP uptake, and the k3. This was unexpected as NSD 1015 directly inhibits the enzyme converting [(11)C]5-HTP to [(11)C]5-HT, suggesting that trapping of radioactivity does not distinguish between parent tracer and its metabolites. As different results have been acquired in monkeys and humans, [(11)C]5-HTP-PET may be suitable for measuring 5-HT synthesis in primates, but not in rodents.

  18. Differential diagnosis of posterior fossa brain tumors: Multiple discriminant analysis of Tl-SPECT and FDG-PET.

    PubMed

    Yamauchi, Moritaka; Okada, Tomohisa; Okada, Tsutomu; Yamamoto, Akira; Fushimi, Yasutaka; Arakawa, Yoshiki; Miyamoto, Susumu; Togashi, Kaori

    2017-08-01

    This study investigated the combined capability of thallium-201 (Tl)-SPECT and fluorine-18-fluoro-deoxy-glucose (FDG)-PET for differential diagnosis of posterior fossa brain tumors using multiple discriminant analysis.This retrospective study was conducted under approval of the institutional review board. In the hospital information system, 27 patients with posterior fossa intra-axial tumor between January 2009 and June 2015 were enrolled and grouped as the following 7 entities: low grade glioma (LGG) 6, anaplastic astrocytoma (AA) 2, glioblastoma (GBM) 3, medulloblastoma (MB) 3, hemangioblastoma (HB) 6, metastatic tumor (Mets) 3, and malignant lymphoma (ML) 4. Tl and FDG uptakes were measured at the tumors and control areas, and several indexes were derived. Using indexes selected by the stepwise method, discriminant analysis was conducted with leave-one-out cross-validation.The predicted accuracy for tumor classification was 70.4% at initial analysis and 55.6% at cross-validation to differentiate 7 tumor entities. HB, LGG, and ML were well-discriminated, but AA was located next to LGG. GBM, MB, and Mets largely overlapped and could not be well distinguished even applying multiple discriminant analysis. Correct classification in the original and cross-validation analyses was 44.4% and 33.3% for Tl-SPECT and 55.6% and 48.1% for FDG-PET.

  19. The synthesis and in vivo evaluation of [18F]PF-9811: a novel PET ligand for imaging brain fatty acid amide hydrolase (FAAH).

    PubMed

    Skaddan, Marc B; Zhang, Lei; Johnson, Douglas S; Zhu, Aijun; Zasadny, Kenneth R; Coelho, Richard V; Kuszpit, Kyle; Currier, Gwen; Fan, Kuo-Hsien; Beck, Elizabeth M; Chen, Laigao; Drozda, Susan E; Balan, Gayatri; Niphakis, Micah; Cravatt, Benjamin F; Ahn, Kay; Bocan, Thomas; Villalobos, Anabella

    2012-10-01

    Fatty acid amide hydrolase (FAAH) is responsible for the enzymatic degradation of the fatty acid amide family of signaling lipids, including the endogenous cannabinoid (endocannabinoid) anandamide. The involvement of the endocannabinoid system in pain and other nervous system disorders has made FAAH an attractive target for drug development. Companion molecular imaging probes are needed, however, to assess FAAH inhibition in the nervous system in vivo. We report here the synthesis and in vivo evaluation of [(18)F]PF-9811, a novel PET ligand for non-invasive imaging of FAAH in the brain. The potency and selectivity of unlabeled PF-9811 were determined by activity-based protein profiling (ABPP) both in vitro and in vivo. [(18)F]PF-9811 was synthesized in a 3-step, one-pot reaction sequence, followed by HPLC purification. Biological evaluation was performed by biodistribution and dynamic PET imaging studies in male rats. The specificity of [(18)F]PF-9811 uptake was evaluated by pre-administration of PF-04457845, a potent and selective FAAH inhibitor, 1h prior to radiotracer injection. Biodistribution studies show good uptake (SUV~0.8 at 90 min) of [(18)F]PF-9811 in rat brain, with significant reduction of the radiotracer in all brain regions (37%-73% at 90 min) in blocking experiments. Dynamic PET imaging experiments in rat confirmed the heterogeneous uptake of [(18)F]PF-9811 in brain regions with high FAAH enzymatic activity, as well as statistically significant reductions in signal following pre-administration of the blocking compound PF-04457845. [(18)F]PF-9811 is a promising PET imaging agent for FAAH. Biodistribution and PET imaging experiments show that the tracer has good uptake in brain, regional heterogeneity, and specific binding as determined by blocking experiments with the highly potent and selective FAAH inhibitor, PF-04457845. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. Differentiation between Treatment-Induced Necrosis and Recurrent Tumors in Patients with Metastatic Brain Tumors: Comparison among (11)C-Methionine-PET, FDG-PET, MR Permeability Imaging, and MRI-ADC-Preliminary Results.

    PubMed

    Tomura, N; Kokubun, M; Saginoya, T; Mizuno, Y; Kikuchi, Y

    2017-08-01

    In patients with metastatic brain tumors after gamma knife radiosurgery, the superiority of PET using (11)C-methionine for differentiating radiation necrosis and recurrent tumors has been accepted. To evaluate the feasibility of MR permeability imaging, it was compared with PET using (11)C-methionine, FDG-PET, and DWI for differentiating radiation necrosis from recurrent tumors. The study analyzed 18 lesions from 15 patients with metastatic brain tumors who underwent gamma knife radiosurgery. Ten lesions were identified as recurrent tumors by an operation. In MR permeability imaging, the transfer constant between intra- and extravascular extracellular spaces (/minute), extravascular extracellular space, the transfer constant from the extravascular extracellular space to plasma (/minute), the initial area under the signal intensity-time curve, contrast-enhancement ratio, bolus arrival time (seconds), maximum slope of increase (millimole/second), and fractional plasma volume were calculated. ADC was also acquired. On both PET using (11)C-methionine and FDG-PET, the ratio of the maximum standard uptake value of the lesion divided by the maximum standard uptake value of the symmetric site in the contralateral cerebral hemisphere was measured ((11)C-methionine ratio and FDG ratio, respectively). The receiver operating characteristic curve was used for analysis. The area under the receiver operating characteristic curve for differentiating radiation necrosis from recurrent tumors was the best for the (11)C-methionine ratio (0.90) followed by the contrast-enhancement ratio (0.81), maximum slope of increase (millimole/second) (0.80), the initial area under the signal intensity-time curve (0.78), fractional plasma volume (0.76), bolus arrival time (seconds) (0.76), the transfer constant between intra- and extravascular extracellular spaces (/minute) (0.74), extravascular extracellular space (0.68), minimum ADC (0.60), the transfer constant from the extravascular

  1. Comparison of two commercial whole body PET systems based on LSO and BGO crystals respectively for brain imaging.

    PubMed

    Trébossen, Régine; Comtat, Claude; Brulon, Vincent; Bailly, Pascal; Meyer, Marc-Etienne

    2009-04-01

    The prevalence of neurodegenerative diseases is growing in western countries and PET imaging is increasingly frequently used for clinical and research purposes. However, few PET cameras are dedicated to cerebral imaging. The Biograph 6 (Biograph6) (Siemens Medical Solutions) is a PET/CT dedicated to high throughput whole body studies. Its performance for cerebral imaging has not yet been assessed. The aims of this study were to compare the quantification and detectability of the Biograph for cerebral imaging with those of a well-validated PET camera, the ECAT EXACT HR+ (HR+) (Siemens Medical Solutions). A phantom measuring 19 cm long and 20 cm in diameter was filled with a 18F-fluorodeoxyglucose (18F-FDG) solution. Two 5.7 and 20 ml spheres filled with water (cold-spots), three 0.25 ml spheres (sphere-to-background: 3, 6, and 12), one 1.14 ml sphere (sphere-to-background: 3), and one 11.27 ml sphere (sphere-to-background: 2) filled with a radioactive solution were inserted into the phantom. The activity concentration was chosen so that the count rates for the phantom measurements matched those of typical brain studies on both cameras. Images were reconstructed using FORE and OSEM algorithms. The reconstruction parameters were adjusted to obtain a similar signal-to-noise ratio in images acquired with the two cameras. The contrast recovery (CR) coefficients were similar on the two scanners for the 5.7 and 20 ml spheres (cold spheres) and the 1.14 and 11.27 ml spheres (hot spheres). For the 0.25 ml spheres, the CR values were 35% higher for the sphere-to-background ratio of 12 and 39% higher for the sphere-to-background ratio of 6 on the Biograph6 for the 3 min scan. The variability of measurements was lower on the Biograph6 than on the HR+. The detectability for the smallest spheres on the Biograph6 was close to that on the HR+. The Biograph has similar performances as the HR+ reference tomograph for the detection and quantification of small hot spots and cold spots.

  2. Evaluating [(11)C]PBR28 PET for Monitoring Gut and Brain Inflammation in a Rat Model of Chemically Induced Colitis.

    PubMed

    Kurtys, E; Doorduin, J; Eisel, U L M; Dierckx, R A J O; de Vries, E F J

    2017-02-01

    Ulcerative colitis (UC) is a chronic inflammatory disease of the colon that affects an increasing number of patients. High comorbidity is observed between UC and other diseases in which inflammation may be involved, including brain diseases such as cognitive impairment, mental disorders, anxiety, and depression. To investigate the increased occurrence of these brain diseases in patients with UC, non-invasive methods for monitoring peripheral and central inflammation could be applied. Therefore, the goal of this study is to assess the feasibility of monitoring gut and brain inflammation in a rat model of chemically induced colitis by positron emission tomography (PET) with [(11)C]PBR28, a tracer targeting the translocator protein (TSPO), which is upregulated when microglia and macrophages are activated. Colitis was induced in rats by intra-rectal injection of 2,4,6-trinitrobenzenesulfonic acid (TNBS). Rats with colitis and healthy control animals were subjected to [(11)C]PBR28 PET of the abdomen followed by ex vivo biodistribution in order to assess whether inflammation in the gut could be detected. Another group of rats with colitis underwent repetitive [(11)C]PBR28 PET imaging of the brain to investigate the development of neuroinflammation. Eleven days after TNBS injection, ex vivo biodistribution studies demonstrated increased [(11)C]PBR28 uptake in the inflamed cecum and colon of rats with colitis as compared to healthy controls, whereas PET imaging did not show any difference between groups at any time. Similarly, repetitive PET imaging of the brain did not reveal any neuroinflammation induced by the TNBS administration in the colon. In contrast, significantly increased [(11)C]PBR28 uptake in cerebellum could be detected in ex vivo biodistribution studies on day 11. Inflammation in both the gut and the brain of rats with chemically induced colitis was observed by ex vivo biodistribution. However, these effects could not be detected by [(11)C]PBR28 PET imaging

  3. Prospective Validation of 18F-FDG Brain PET Discriminant Analysis Methods in the Diagnosis of Amyotrophic Lateral Sclerosis.

    PubMed

    Van Weehaeghe, Donatienne; Ceccarini, Jenny; Delva, Aline; Robberecht, Wim; Van Damme, Philip; Van Laere, Koen

    2016-08-01

    An objective biomarker for early identification and accurate differential diagnosis of amyotrophic lateral sclerosis (ALS) is lacking. (18)F-FDG PET brain imaging with advanced statistical analysis may provide a tool to facilitate this. The objective of this work was to validate volume-of-interest (VOI) and voxel-based (using a support vector machine [SVM] approach) (18)F-FDG PET analysis methods to differentiate ALS from controls in an independent prospective large cohort, using a priori-derived classifiers. Furthermore, the prognostic value of (18)F-FDG PET was evaluated. A prospective cohort of patients with a suspected diagnosis of a motor neuron disorder (n = 119; mean age ± SD, 61 ± 12 y; 81 men and 38 women) was recruited. One hundred five patients were diagnosed with ALS (mean age ± SD, 61.0 ± 12 y; 74 men and 31 women) (group 2), 10 patients with primary lateral sclerosis (mean age ± SD, 55.5 ± 12 y; 3 men and 7 women), and 4 patients with progressive muscular atrophy (mean age ± SD, 59.2 ± 5 y; 4 men). The mean disease duration of all patients was 15.0 ± 13.4 mo at diagnosis, with PET conducted 15.2 ± 13.3 mo after the first symptoms. Data were compared with a previously gathered dataset of 20 screened healthy subjects (mean age ± SD, 62.4 ± 6.4 y; 12 men and 8 women) and 70 ALS patients (mean age ± SD, 62.2 ± 12.5 y; 44 men and 26 women) (group 1). Data were spatially normalized and analyzed on a VOI basis (statistical software (using the Hammers atlas) and voxel basis using statistical parametric mapping. Discriminant analysis and SVM were used to classify new cases based on the classifiers derived from group 1. Compared with controls, ALS patients showed a nearly identical pattern of hypo- and hypermetabolism in groups 1 and 2. VOI-based discriminant analysis resulted in an 88.8% accuracy in predicting the new ALS cases. For the SVM approach, this accuracy was 100%. Brain metabolism between ALS and primary lateral sclerosis patients was

  4. Impact of (18)FDG PET and (11)C-PIB PET brain imaging on the diagnosis of Alzheimer's disease and other dementias in a regional memory clinic in Hong Kong.

    PubMed

    Shea, Y F; Ha, J; Lee, S C; Chu, L W

    2016-08-01

    This study investigated the improvement in the accuracy of diagnosis of dementia subtypes among Chinese dementia patients who underwent [18F]-2-fluoro-2-deoxy-D-glucose positron emission tomography ((18)FDG PET) with or without carbon 11-labelled Pittsburgh compound B ((11)C-PIB). This case series was performed in the Memory Clinic at Queen Mary Hospital, Hong Kong. We reviewed 109 subjects (56.9% were female) who received PET with or without (11)C-PIB between January 2007 and December 2014. Data including age, sex, education level, Mini-Mental State Examination score, Clinical Dementia Rating scale score, neuroimaging report, and pre-/post-imaging clinical diagnoses were collected from medical records. The agreement between the initial and post-PET with or without (11)C-PIB dementia diagnosis was analysed by the Cohen's kappa statistics. The overall accuracy of initial clinical diagnosis of dementia subtype was 63.7%, and diagnosis was subsequently changed in 36.3% of subjects following PET with or without (11)C-PIB. The rate of accurate initial clinical diagnosis (compared with the final post-imaging diagnosis) was 81.5%, 44.4%, 14.3%, 28.6%, 55.6% and 0% for Alzheimer's disease, dementia with Lewy bodies, frontotemporal dementia, vascular dementia, other dementia, and mixed dementia, respectively. The agreement between the initial and final post-imaging dementia subtype diagnosis was only fair, with a Cohen's kappa of 0.25 (95% confidence interval, 0.05-0.45). For the 21 subjects who underwent (11)C-PIB PET imaging, 19% (n=4) of those with Alzheimer's disease (PIB positive) were initially diagnosed with non-Alzheimer's disease dementia. In this study, PET with or without (11)C-PIB brain imaging helped improve the accuracy of diagnosis of dementia subtype in 36% of our patients with underlying Alzheimer's disease, dementia with Lewy bodies, vascular dementia, and frontotemporal dementia.

  5. Reproducible Analysis of Rat Brain PET Studies Using an Additional [18F]NaF Scan and an MR-Based ROI Template

    PubMed Central

    Buiter, Hans J. C.; van Velden, Floris H. P.; Leysen, Josée E.; Fisher, Abraham; Windhorst, Albert D.; Lammertsma, Adriaan A.; Huisman, Marc C.

    2012-01-01

    Background. An important step in the analysis of positron emission tomography (PET) studies of the brain is the definition of regions of interest (ROI). Image coregistration, ROI analysis, and quantification of brain PET data in small animals can be observer dependent. The purpose of this study was to investigate the feasibility of ROI analysis based on a standard MR template and an additional [18F]NaF scan. Methods. [18F]NaF scans of 10 Wistar rats were coregistered with a standard MR template by 3 observers and derived transformation matrices were applied to corresponding [11C]AF150(S) images. Uptake measures were derived for several brain regions delineated using the MR template. Overall agreement between the 3 observers was assessed by interclass correlation coefficients (ICC) of uptake data. In addition, [11C]AF150(S) ROI data were compared with ex vivo biodistribution data. Results. For all brain regions, ICC analysis showed excellent agreement between observers. Reproducibility, estimated by calculation of standard deviation of the between-observer differences, was demonstrated by an average of 17% expressed as coefficient of variation. Uptake of [11C]AF150(S) derived from ROI analysis closely matched ex vivo biodistribution data. Conclusions. The proposed method provides a reproducible and tracer-independent method for ROI analysis of rat brain PET data. PMID:23050141

  6. Joint penalized-likelihood reconstruction of time-activity curves and regions-of-interest from projection data in brain PET.

    PubMed

    Krestyannikov, E; Tohka, J; Ruotsalainen, U

    2008-06-07

    This paper presents a novel statistical approach for joint estimation of regions-of-interest (ROIs) and the corresponding time-activity curves (TACs) from dynamic positron emission tomography (PET) brain projection data. It is based on optimizing the joint objective function that consists of a data log-likelihood term and two penalty terms reflecting the available a priori information about the human brain anatomy. The developed local optimization strategy iteratively updates both the ROI and TAC parameters and is guaranteed to monotonically increase the objective function. The quantitative evaluation of the algorithm is performed with numerically and Monte Carlo-simulated dynamic PET brain data of the 11C-Raclopride and 18F-FDG tracers. The results demonstrate that the method outperforms the existing sequential ROI quantification approaches in terms of accuracy, and can noticeably reduce the errors in TACs arising due to the finite spatial resolution and ROI delineation.

  7. Reconstruction of an input function from a dynamic PET water image using multiple tissue curves

    NASA Astrophysics Data System (ADS)

    Kudomi, Nobuyuki; Maeda, Yukito; Yamamoto, Yuka; Nishiyama, Yoshihiro

    2016-08-01

    Quantification of cerebral blood flow (CBF) is important for the understanding of normal and pathologic brain physiology. When CBF is assessed using PET with {{\\text{H}}2} 15O or C15O2, its calculation requires an arterial input function, which generally requires invasive arterial blood sampling. The aim of the present study was to develop a new technique to reconstruct an image derived input function (IDIF) from a dynamic {{\\text{H}}2} 15O PET image as a completely non-invasive approach. Our technique consisted of using a formula to express the input using tissue curve with rate constant parameter. For multiple tissue curves extracted from the dynamic image, the rate constants were estimated so as to minimize the sum of the differences of the reproduced inputs expressed by the extracted tissue curves. The estimated rates were used to express the inputs and the mean of the estimated inputs was used as an IDIF. The method was tested in human subjects (n  =  29) and was compared to the blood sampling method. Simulation studies were performed to examine the magnitude of potential biases in CBF and to optimize the number of multiple tissue curves used for the input reconstruction. In the PET study, the estimated IDIFs were well reproduced against the measured ones. The difference between the calculated CBF values obtained using the two methods was small as around  <8% and the calculated CBF values showed a tight correlation (r  =  0.97). The simulation showed that errors associated with the assumed parameters were  <10%, and that the optimal number of tissue curves to be used was around 500. Our results demonstrate that IDIF can be reconstructed directly from tissue curves obtained through {{\\text{H}}2} 15O PET imaging. This suggests the possibility of using a completely non-invasive technique to assess CBF in patho-physiological studies.

  8. A PET/MR Imaging Approach for the Integrated Assessment of Chemotherapy-induced Brain, Heart, and Bone Injuries in Pediatric Cancer Survivors: A Pilot Study.

    PubMed

    Theruvath, Ashok J; Ilivitzki, Anat; Muehe, Anne; Theruvath, Johanna; Gulaka, Praveen; Kim, Christine; Luna-Fineman, Sandra; Sakamoto, Kathleen M; Yeom, Kristen W; Yang, Phillip; Moseley, Michael; Chan, Frandics; Daldrup-Link, Heike E

    2017-08-04

    Purpose To develop a positron emission tomography (PET)/magnetic resonance (MR) imaging protocol for evaluation of the brain, heart, and joints of pediatric cancer survivors for chemotherapy-induced injuries in one session. Materials and Methods Three teams of experts in neuroimaging, cardiac imaging, and bone imaging were tasked to develop a 20-30-minute PET/MR imaging protocol for detection of chemotherapy-induced tissue injuries of the brain, heart, and bone. In an institutional review board-approved, HIPAA-compliant, prospective study from April to July 2016, 10 pediatric cancer survivors who completed chemotherapy underwent imaging of the brain, heart, and bone with a 3-T PET/MR imager. Cumulative chemotherapy doses and clinical symptoms were correlated with the severity of MR imaging abnormalities by using linear regression analyses. MR imaging measures of brain perfusion and metabolism were compared among eight patients who were treated with methotrexate and eight untreated age-matched control subjects by using Wilcoxon rank-sum tests. Results Combined brain, heart, and bone examinations were completed within 90 minutes. Eight of 10 cancer survivors had abnormal findings on brain, heart, and bone images, including six patients with and two patients without clinical symptoms. Cumulative chemotherapy doses correlated significantly with MR imaging measures of left ventricular ejection fraction and end-systolic volume, but not with the severity of brain or bone abnormalities. Methotrexate-treated cancer survivors had significantly lower cerebral blood flow and metabolic activity in key brain areas compared with control subjects. Conclusion The feasibility of a single examination for assessment of chemotherapy-induced injuries of the brain, heart, and joints was shown. Earlier detection of tissue injuries may enable initiation of timely interventions and help to preserve long-term health of pediatric cancer survivors. (©) RSNA, 2017 Online supplemental material

  9. SU-D-9A-04: Brain PET/CT Imaging On a Scanner with a Large Axial Field-Of-View

    SciTech Connect

    Park, M; Gerbaudo, V; Hamberg, L; Seaver, K; Kijewski, M

    2014-06-01

    Purpose: Large axial field-of-view (FOV) PET/CT scanners are valued for high sensitivity. Brain PET image quality may depend on the head position within the FOV. We investigated the precision of activity estimation for brain PET imaging when the brain was positioned at the end (END) and in the middle (CEN) of the FOV. The additional CT dose for the CEN position was recorded. Methods: An image quality (Jaszczak) phantom and a striatal phantom were filled with F-18 and positioned in END and CEN locations. For each phantom and each location, we acquired a ∼1-hr listmode PET, rebinned the data into 10 frames with equal number of coincidence events, and reconstructed each frame using an iterative algorithm. For the striatal phantom, END and CEN were compared by drawing on each image three regions of interest (ROI) in axially separated uniform areas. The standard deviation of the activity estimation within each ROI was averaged over the 10 images. The coefficient of variation (CV) for activity estimation was calculated at each position. Image quality was assessed by inspecting the resolution bar pattern in the Jaszczak phantom at two different head positions. Results: The CV was the lowest for ROIs near the center of the FOV. For slices near the end, not only was the CV highest, but also the resolution pattern was degraded. CTDIvol summarized in the dose report indicated that the CT dose was ∼ 10% higher for CEN as compared to END position. Conclusion: Positioning the brain in the middle of the FOV in a large FOV PET/CT scanner allows more precise measurement of tracer uptake and better image quality at the cost of increased CT dose. For the end location longer scan times may minimize image quality degradation without any additional CT dose.

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

    SciTech Connect

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

    2015-06-15

    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{sup 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 CA

  11. Coupling between physiological TSPO expression in brain and myocardium allows stabilization of late-phase cerebral [(18)F]GE180 PET quantification.

    PubMed

    Deussing, Maximilian; Blume, Tanja; Vomacka, Lena; Mahler, Christoph; Focke, Carola; Todica, Andrei; Unterrainer, Marcus; Albert, Nathalie L; Lindner, Simon; von Ungern-Sternberg, Barbara; Baumann, Karlheinz; Zwergal, Andreas; Bartenstein, Peter; Herms, Jochen; Rominger, Axel; Brendel, Matthias

    2017-10-05

    PET imaging of the 18 kDa translocator protein (TSPO), a biomarker of microglial activity, receives growing interest in clinical and preclinical applications of neuroinflammatory and neurodegenerative brain diseases. In globally affected brains, intra-cerebral pseudo reference regions are not feasible. Consequently, many brain-independent approaches have been attempted, including SUV analysis and normalization to muscle- or heart uptake, aiming to stabilize quantitative analysis. In this study, we systematically compared different image normalization methods for static late phase TSPO-PET imaging of rodent brain. We first obtained gamma counter measurements for gold standard quantitation of [(18)F]GE180 uptake in brain of C57Bl/6 mice (N = 10) after PET, aiming to identify factors contributing significantly to the quantitative results. Subsequently, data from a large cohort of C57Bl/6 mice (N = 79) were compiled to precisely determine the weighted influence and variance attributable these factors by regression analysis. Scan-rescan variability and agreement with histology were used to validate the tested normalization methods in an Alzheimer's disease (AD) mouse model with pathologically increased TSPO expression (PS2APP; N = 24). Longitudinal data from AD model mice (N = 10) scanned at four different ages were used to challenge and validate the different normalization methods in a practical application. Gamma counter results revealed that injected dose, body weight and PET-measured radioactivity concentration in the ventral myocardium all significantly accounted for [(18)F]GE180 activity in the brain. Skeletal muscle activity had high test-retest variance in this PET only application and was therefore pursued no further. Regression analysis of the large scale evaluation showed that scaling to injected dose or SUV analysis accounted for little variance in brain activity (R(2) < 0.5), but inclusion of myocardial activity together with injected dose and

  12. Reversal of brain metabolic abnormalities following treatment of AIDS dementia complex with 3'-azido-2',3'-dideoxythymidine (AZT, zidovudine): a PET-FDG study

    SciTech Connect

    Brunetti, A.; Berg, G.; Di Chiro, G.; Cohen, R.M.; Yarchoan, R.; Pizzo, P.A.; Broder, S.; Eddy, J.; Fulham, M.J.; Finn, R.D.

    1989-05-01

    Brain glucose metabolism was evaluated in four patients with acquired immunodeficiency syndrome (AIDS) dementia complex using (/sup 18/F)fluorodeoxyglucose (FDG) and positron emission tomography (PET) scans at the beginning of therapy with 3'-azido-2',3'-dideoxythymidine (AZT, zidovudine), and later in the course of therapy. In two patients, baseline, large focal cortical abnormalities of glucose utilization were reversed during the course of therapy. In the other two patients, the initial PET study did not reveal pronounced focal alterations, while the post-treatment scans showed markedly increased cortical glucose metabolism. The improved cortical glucose utilization was accompanied in all patients by immunologic and neurologic improvement. PET-FDG studies can detect cortical metabolic abnormalities associated with AIDS dementia complex, and may be used to monitor the metabolic improvement in response to AZT treatment.

  13. Large Variation in Brain Exposure of Reference CNS Drugs: a PET Study in Nonhuman Primates

    PubMed Central

    Varnäs, Katarina; Lundquist, Stefan; Nakao, Ryuji; Amini, Nahid; Takano, Akihiro; Finnema, Sjoerd J.; Halldin, Christer; Farde, Lars

    2015-01-01

    Background: Positron emission tomography microdosing of radiolabeled drugs allows for noninvasive studies of organ exposure in vivo. The aim of the present study was to examine and compare the brain exposure of 12 commercially available CNS drugs and one non-CNS drug. Methods: The drugs were radiolabeled with 11C (t 1/2 = 20.4 minutes) and examined using a high resolution research tomograph. In cynomolgus monkeys, each drug was examined twice. In rhesus monkeys, a first positron emission tomography microdosing measurement was repeated after preadministration with unlabeled drug to examine potential dose-dependent effects on brain exposure. Partition coefficients between brain and plasma (K P) were calculated by dividing the AUC0-90 min for brain with that for plasma or by a compartmental analysis (V T). Unbound K P (K P u,u) was obtained by correction for the free fraction in brain and plasma. Results: After intravenous injection, the maximum radioactivity concentration (C max, %ID) in brain ranged from 0.01% to 6.2%. For 10 of the 12 CNS drugs, C max, %ID was >2%, indicating a preferential distribution to brain. A lower C max, %ID was observed for morphine, sulpiride, and verapamil. K P ranged from 0.002 (sulpiride) to 68 (sertraline) and 7 of 13 drugs had K P u,u close to unity. For morphine, sulpiride, and verapamil, K P u,u was <0.3, indicating impaired diffusion and/or active efflux. Brain exposure at microdosing agreed with pharmacological dosing conditions for the investigated drugs. Conclusions: This study represents the largest positron emission tomography study on brain exposure of commercially available CNS drugs in nonhuman primates and may guide interpretation of positron emission tomography microdosing data for novel drug candidates. PMID:25813017

  14. Insights into Intrinsic Brain Networks based on Graph Theory and PET in right- compared to left-sided Temporal Lobe Epilepsy

    PubMed Central

    Vanicek, Thomas; Hahn, Andreas; Traub-Weidinger, Tatjana; Hilger, Eva; Spies, Marie; Wadsak, Wolfgang; Lanzenberger, Rupert; Pataraia, Ekaterina; Asenbaum-Nan, Susanne

    2016-01-01

    The human brain exhibits marked hemispheric differences, though it is not fully understood to what extent lateralization of the epileptic focus is relevant. Preoperative [18F]FDG-PET depicts lateralization of seizure focus in patients with temporal lobe epilepsy and reveals dysfunctional metabolic brain connectivity. The aim of the present study was to compare metabolic connectivity, inferred from inter-regional [18F]FDG PET uptake correlations, in right-sided (RTLE; n = 30) and left-sided TLE (LTLE; n = 32) with healthy controls (HC; n = 31) using graph theory based network analysis. Comparing LTLE and RTLE and patient groups separately to HC, we observed higher lobar connectivity weights in RTLE compared to LTLE for connections of the temporal and the parietal lobe of the contralateral hemisphere (CH). Moreover, especially in RTLE compared to LTLE higher local efficiency were found in the temporal cortices and other brain regions of the CH. The results of this investigation implicate altered metabolic networks in patients with TLE specific to the lateralization of seizure focus, and describe compensatory mechanisms especially in the CH of patients with RTLE. We propose that graph theoretical analysis of metabolic connectivity using [18F]FDG-PET offers an important additional modality to explore brain networks. PMID:27349503

  15. Insights into Intrinsic Brain Networks based on Graph Theory and PET in right- compared to left-sided Temporal Lobe Epilepsy.

    PubMed

    Vanicek, Thomas; Hahn, Andreas; Traub-Weidinger, Tatjana; Hilger, Eva; Spies, Marie; Wadsak, Wolfgang; Lanzenberger, Rupert; Pataraia, Ekaterina; Asenbaum-Nan, Susanne

    2016-06-28

    The human brain exhibits marked hemispheric differences, though it is not fully understood to what extent lateralization of the epileptic focus is relevant. Preoperative [(18)F]FDG-PET depicts lateralization of seizure focus in patients with temporal lobe epilepsy and reveals dysfunctional metabolic brain connectivity. The aim of the present study was to compare metabolic connectivity, inferred from inter-regional [(18)F]FDG PET uptake correlations, in right-sided (RTLE; n = 30) and left-sided TLE (LTLE; n = 32) with healthy controls (HC; n = 31) using graph theory based network analysis. Comparing LTLE and RTLE and patient groups separately to HC, we observed higher lobar connectivity weights in RTLE compared to LTLE for connections of the temporal and the parietal lobe of the contralateral hemisphere (CH). Moreover, especially in RTLE compared to LTLE higher local efficiency were found in the temporal cortices and other brain regions of the CH. The results of this investigation implicate altered metabolic networks in patients with TLE specific to the lateralization of seizure focus, and describe compensatory mechanisms especially in the CH of patients with RTLE. We propose that graph theoretical analysis of metabolic connectivity using [(18)F]FDG-PET offers an important additional modality to explore brain networks.

  16. Comparison of five cluster validity indices performance in brain [(18) F]FET-PET image segmentation using k-means.

    PubMed

    Abualhaj, Bedor; Weng, Guoyang; Ong, Melissa; Attarwala, Ali Asgar; Molina, Flavia; Büsing, Karen; Glatting, Gerhard

    2017-01-01

    Dynamic [(18) F]fluoro-ethyl-L-tyrosine positron emission tomography ([(18) F]FET-PET) is used to identify tumor lesions for radiotherapy treatment planning, to differentiate glioma recurrence from radiation necrosis and to classify gliomas grading. To segment different regions in the brain k-means cluster analysis can be used. The main disadvantage of k-means is that the number of clusters must be pre-defined. In this study, we therefore compared different cluster validity indices for automated and reproducible determination of the optimal number of clusters based on the dynamic PET data. The k-means algorithm was applied to dynamic [(18) F]FET-PET images of 8 patients. Akaike information criterion (AIC), WB, I, modified Dunn's and Silhouette indices were compared on their ability to determine the optimal number of clusters based on requirements for an adequate cluster validity index. To check the reproducibility of k-means, the coefficients of variation CVs of the objective function values OFVs (sum of squared Euclidean distances within each cluster) were calculated using 100 random centroid initialization replications RCI100 for 2 to 50 clusters. k-means was performed independently on three neighboring slices containing tumor for each patient to investigate the stability of the optimal number of clusters within them. To check the independence of the validity indices on the number of voxels, cluster analysis was applied after duplication of a slice selected from each patient. CVs of index values were calculated at the optimal number of clusters using RCI100 to investigate the reproducibility of the validity indices. To check if the indices have a single extremum, visual inspection was performed on the replication with minimum OFV from RCI100 . The maximum CV of OFVs was 2.7 × 10(-2) from all patients. The optimal number of clusters given by modified Dunn's and Silhouette indices was 2 or 3 leading to a very poor segmentation. WB and I indices suggested in

  17. PET with radiolabeled aminoacid.

    PubMed

    Crippa, F; Alessi, A; Serafini, G L

    2012-04-01

    Since the clinical introduction of FDG, neuroimaging has been the first area of PET application in oncology. Later, while FDG-PET became progressively a key imaging modality in the management of the majority of malignancies outside the brain, its neuro-oncologic indications faced some limitations because of the unfavourable characteristics of FDG as brain tumor-seeking agent. PET applications in neuro-oncology have received new effectiveness by the advent of positron-emission labelled amino acids, so that it has been coined the term "Amino acid PET" to differentiate this imaging tool from FDG-PET. Radiolabeled amino acids are a very interesting class of PET tracers with great diagnostic potential in neuro-oncology because of their low uptake in normal brain and, conversely, high uptake in most brain tumors including low-grade gliomas. The present article surveys the results obtained using L-[methyl-11C]Methionine (MET), that has been the ancestor of PET amino acid tracers and is still the most popular amino acid imaging modality in oncology, and stresses the important role that this diagnostic modality can play in the evaluation of brain tumors. However, the use of MET is restricted to PET centers with an in-house cyclotron and radiochemistry facility, because of the short half-life (20 min) of 11C. The promising results of MET have stimulated the development of 18F-labelled aminoacid tracers, particularly O-(2-18F-fluoeoethyl1)-L-tyrosine (FET), that has the same properties of MET and, thanks to the longer half-life of 18F (about 110 min), allows a distribution strategy from a production tracer site to user satellite PET centers. Considering a more widespread use of Amino acid PET, together with the recent development of integrated PET-MRI imaging systems, and the oncoming clinical validation of other interesting PET tracers, i.e. FMISO or 18F-FAZA for hypoxia imaging and FLT for tumor proliferation imaging, it can be reasonably expected that metabolic imaging

  18. PET Mapping for Brain-Computer Interface Stimulation of the Ventroposterior Medial Nucleus of the Thalamus in Rats with Implanted Electrodes.

    PubMed

    Zhu, Yunqi; Xu, Kedi; Xu, Caiyun; Zhang, Jiacheng; Ji, Jianfeng; Zheng, Xiaoxiang; Zhang, Hong; Tian, Mei

    2016-07-01

    Brain-computer interface (BCI) technology has great potential for improving the quality of life for neurologic patients. This study aimed to use PET mapping for BCI-based stimulation in a rat model with electrodes implanted in the ventroposterior medial (VPM) nucleus of the thalamus. PET imaging studies were conducted before and after stimulation of the right VPM. Stimulation induced significant orienting performance. (18)F-FDG uptake increased significantly in the paraventricular thalamic nucleus, septohippocampal nucleus, olfactory bulb, left crus II of the ansiform lobule of the cerebellum, and bilaterally in the lateral septum, amygdala, piriform cortex, endopiriform nucleus, and insular cortex, but it decreased in the right secondary visual cortex, right simple lobule of the cerebellum, and bilaterally in the somatosensory cortex. This study demonstrated that PET mapping after VPM stimulation can identify specific brain regions associated with orienting performance. PET molecular imaging may be an important approach for BCI-based research and its clinical applications. © 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

  19. Frightening music triggers rapid changes in brain monoamine receptors: a pilot PET study.

    PubMed

    Zhang, Ying; Chen, Qiaozhen; Du, Fenglei; Hu, Yanni; Chao, Fangfang; Tian, Mei; Zhang, Hong

    2012-10-01

    Frightening music can rapidly arouse emotions in listeners that mimic those from actual life-threatening experiences. However, studies of the underlying mechanism for perceiving danger created by music are limited. We investigated monoamine receptor changes induced by frightening music using (11)C-N-methyl-spiperone ((11)C-NMSP) PET. Ten healthy male volunteers were included, and their psychophysiologic changes were evaluated. Compared with the baseline condition, listening to frightening music caused a significant decrease in (11)C-NMSP in the right and left caudate nuclei, right limbic region, and right paralimbic region; a particularly significant decrease in the right anterior cingulate cortex; but an increase in the right frontal occipital and left temporal lobes of the cerebral cortex. Transient fright triggers rapid changes in monoamine receptors, which decrease in the limbic and paralimbic regions but increase in the cerebral cortex.

  20. Brain metabolism in patients with hepatic encephalopathy studied by PET and MR.

    PubMed

    Keiding, Susanne; Pavese, Nicola

    2013-08-15

    We review PET- and MR studies on hepatic encephalopathy (HE) metabolism in human subjects from the point of views of methods, methodological assumptions and use in studies of cirrhotic patients with clinically overt HE, cirrhotic patients with minimal HE, cirrhotic patients with no history of HE and healthy subjects. Key results are: (1) Cerebral oxygen uptake and blood flow are reduced to 2/3 in cirrhotic patients with clinically overt HE but not in cirrhotic patients with minimal HE or no HE compared to healthy subjects. (2) Cerebral ammonia metabolism is enhanced due to increased blood ammonia in cirrhotic patients but the kinetics of cerebral ammonia uptake and metabolism is not affected by hyperammonemia. (3) Recent advantages in MR demonstrate low-grade cerebral oedema not only in astrocytes but also in the white matter in cirrhotic patients with HE.

  1. RESOLUTE PET/MRI Attenuation Correction for O-(2-(18)F-fluoroethyl)-L-tyrosine (FET) in Brain Tumor Patients with Metal Implants.

    PubMed

    Ladefoged, Claes N; Andersen, Flemming L; Kjær, Andreas; Højgaard, Liselotte; Law, Ian

    2017-01-01

    Aim: Positron emission tomography (PET) imaging is a useful tool for assisting in correct differentiation of tumor progression from reactive changes, and the radiolabeled amino acid analog tracer O-(2-(18)F-fluoroethyl)-L-tyrosine (FET)-PET is amongst the most frequently used. The FET-PET images need to be quantitatively correct in order to be used clinically, which require accurate attenuation correction (AC) in PET/MRI. The aim of this study was to evaluate the use of the subject-specific MR-derived AC method RESOLUTE in post-operative brain tumor patients. Methods: We analyzed 51 post-operative brain tumor patients (68 examinations, 200 MBq [18F]-FET) investigated in a PET/MRI scanner. MR-AC maps were acquired using: (1) the Dixon water fat separation sequence, (2) the ultra short echo time (UTE) sequences, (3) calculated using our new RESOLUTE methodology, and (4) a same day low-dose CT used as reference "gold standard." For each subject and each AC method the tumor was delineated by isocontouring tracer uptake above a tumor(T)-to-brain background (B) activity ratio of 1.6. We measured B, tumor mean and maximal activity (TMEAN, TMAX), biological tumor volume (BTV), and calculated the clinical metrics TMEAN/B and TMAX/B. Results: When using RESOLUTE 5/68 studies did not meet our predefined acceptance criteria of TMAX/B difference to CT-AC < ±0.1 or 5%, TMEAN/B < ±0.05 or 5%, and BTV < ±2 mL or 10%. In total, 46/68 studies failed our acceptance criteria using Dixon, and 26/68 using UTE. The 95% limits of agreement for TMAX/B was for RESOLUTE (-3%; 4%), Dixon (-9%; 16%), and UTE (-7%; 10%). The absolute error when measuring BTV was 0.7 ± 1.9 mL (N.S) with RESOLUTE, 5.3 ± 10 mL using Dixon, and 1.7 ± 3.7 mL using UTE. RESOLUTE performed best in the identification of the location of peak activity and in brain tumor follow-up monitoring using clinical FET PET metrics. Conclusions: Overall, we found RESOLUTE to be the AC method that most robustly reproduced the

  2. Pilot PET Study to Assess the Functional Interplay Between ABCB1 and ABCG2 at the Human Blood–Brain Barrier

    PubMed Central

    Bauer, M; Römermann, K; Karch, R; Wulkersdorfer, B; Stanek, J; Philippe, C; Maier‐Salamon, A; Haslacher, H; Jungbauer, C; Wadsak, W; Jäger, W; Löscher, W; Hacker, M; Zeitlinger, M

    2016-01-01

    ABCB1 and ABCG2 work together at the blood–brain barrier (BBB) to limit brain distribution of dual ABCB1/ABCG2 substrates. In this pilot study we used positron emission tomography (PET) to assess brain distribution of two model ABCB1/ABCG2 substrates ([11C]elacridar and [11C]tariquidar) in healthy subjects without (c.421CC) or with (c.421CA) the ABCG2 single‐nucleotide polymorphism (SNP) c.421C>A. Subjects underwent PET scans under conditions when ABCB1 and ABCG2 were functional and during ABCB1 inhibition with high‐dose tariquidar. In contrast to the ABCB1‐selective substrate (R)‐[11C]verapamil, [11C]elacridar and [11C]tariquidar showed only moderate increases in brain distribution during ABCB1 inhibition. This provides evidence for a functional interplay between ABCB1 and ABCG2 at the human BBB and suggests that both ABCB1 and ABCG2 need to be inhibited to achieve substantial increases in brain distribution of dual ABCB1/ABCG2 substrates. During ABCB1 inhibition c.421CA subjects had significantly higher increases in [11C]tariquidar brain distribution than c.421CC subjects, pointing to impaired cerebral ABCG2 function. PMID:26940368

  3. Pilot PET Study to Assess the Functional Interplay Between ABCB1 and ABCG2 at the Human Blood-Brain Barrier.

    PubMed

    Bauer, M; Römermann, K; Karch, R; Wulkersdorfer, B; Stanek, J; Philippe, C; Maier-Salamon, A; Haslacher, H; Jungbauer, C; Wadsak, W; Jäger, W; Löscher, W; Hacker, M; Zeitlinger, M; Langer, O

    2016-08-01

    ABCB1 and ABCG2 work together at the blood-brain barrier (BBB) to limit brain distribution of dual ABCB1/ABCG2 substrates. In this pilot study we used positron emission tomography (PET) to assess brain distribution of two model ABCB1/ABCG2 substrates ([(11) C]elacridar and [(11) C]tariquidar) in healthy subjects without (c.421CC) or with (c.421CA) the ABCG2 single-nucleotide polymorphism (SNP) c.421C>A. Subjects underwent PET scans under conditions when ABCB1 and ABCG2 were functional and during ABCB1 inhibition with high-dose tariquidar. In contrast to the ABCB1-selective substrate (R)-[(11) C]verapamil, [(11) C]elacridar and [(11) C]tariquidar showed only moderate increases in brain distribution during ABCB1 inhibition. This provides evidence for a functional interplay between ABCB1 and ABCG2 at the human BBB and suggests that both ABCB1 and ABCG2 need to be inhibited to achieve substantial increases in brain distribution of dual ABCB1/ABCG2 substrates. During ABCB1 inhibition c.421CA subjects had significantly higher increases in [(11) C]tariquidar brain distribution than c.421CC subjects, pointing to impaired cerebral ABCG2 function. © 2016, The Authors. Clinical Pharmacology & Therapeutics published by Wiley Periodicals, Inc. on behalf of American Society for Clinical Pharmacology and Therapeutics.

  4. Blood-brain barrier permeability of ginkgolide: Comparison of the behavior of PET probes 7α-[(18)F]fluoro- and 10-O-p-[(11)C]methylbenzyl ginkgolide B in monkey and rat brains.

    PubMed

    Doi, Hisashi; Sato, Kengo; Shindou, Hideo; Sumi, Kengo; Koyama, Hiroko; Hosoya, Takamitsu; Watanabe, Yasuyoshi; Ishii, Satoshi; Tsukada, Hideo; Nakanishi, Koji; Suzuki, Masaaki

    2016-11-01

    The blood-brain barrier permeability of ginkgolide B was examined using positron emission tomography (PET) probes of a (18)F-incorporated ginkgolide B ([(18)F]-2) and a (11)C-incorporated methylbenzyl-substituted ginkgolide B ([(11)C]-3). PET studies in monkeys showed low uptake of [(18)F]-2 into the brain, but small amounts of [(11)C]-3 were accumulated in the parenchyma. Furthermore, when cyclosporine A was preadministered to rats, the accumulation of [(18)F]-2 in the rat brain did not significantly change, however, the accumulation of [(11)C]-3 was five times higher than that in the control rat. These results provide effective approaches for investigating the drug potential of ginkgolides. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. PET/CT imaging of the diapeutic alkylphosphocholine analog (124)I-CLR1404 in high and low-grade brain tumors.

    PubMed

    Hall, Lance T; Titz, Benjamin; Robins, H Ian; Bednarz, Bryan P; Perlman, Scott B; Weichert, Jamey P; Kuo, John S

    2017-01-01

    CLR1404 is a cancer-selective alkyl phosphocholine (APC) analog that can be radiolabeled with (124)I for PET imaging, (131)I for targeted radiotherapy and/or SPECT imaging, or (125)I for targeted radiotherapy. Studies have demonstrated avid CLR1404 uptake and prolonged retention in a broad spectrum of preclinical tumor models. The purpose of this pilot trial was to demonstrate avidity of (124)I-CLR1404 in human brain tumors and develop a framework to evaluate this uptake for use in larger studies. 12 patients (8 men and 4 women; mean age of 43.9 ± 15.1 y; range 23-66 y) with 13 tumors were enrolled. Eleven patients had suspected tumor recurrence and 1 patient had a new diagnosis of high grade tumor. Patients were injected with 185 MBq ± 10% of (124)I-CLR1404 followed by PET/CT imaging at 6-, 24-, and 48-hour. (124)I-CLR1404 PET uptake was assessed qualitatively and compared with MRI. After PET image segmentation SUV values and tumor to background ratios were calculated. There was no significant uptake of (124)I-CLR1404 in normal brain. In tumors, uptake tended to increase to 48 hours. Positive uptake was detected in 9 of 13 lesions: 5/5 high grade tumors, 1/2 low grade tumors, 1/1 meningioma, and 2/4 patients with treatment related changes. (124)I-CLR1404 uptake was not detected in 1/2 low grade tumors, 2/4 lesions from treatment related changes, and 1/1 indeterminate lesion. For 6 malignant tumors, the average tumor to background ratios (TBR) were 9.32 ± 4.33 (range 3.46 to 15.42) at 24 hours and 10.04 ± 3.15 (range 5.17 to 13.17) at 48 hours. For 2 lesions from treatment related change, the average TBR were 5.05 ± 0.4 (range 4.76 to 5.33) at 24 hours and 4.88 ± 1.19 (range 4.04 to 5.72) at 48 hours. PET uptake had areas of both concordance and discordance compared with MRI. (124)I-CLR1404 PET demonstrated avid tumor uptake in a variety of brain tumors with high tumor-to-background ratios. There were regions of concordance and discordance compared with MRI

  6. Role of ¹⁸F-FDG PET imaging in paediatric primary dystonia and dystonia arising from neurodegeneration with brain iron accumulation.

    PubMed

    Szyszko, Teresa A; Dunn, Joel T; O'Doherty, Michael J; Reed, Laurence; Lin, Jean-Pierre

    2015-05-01

    No current neuroimaging modality offers mechanistic or prognostic information to guide management in paediatric dystonia. We assessed F-fluorodeoxyglucose (¹⁸F-FDG) PET/computed tomography (CT) brain imaging in childhood primary dystonia (PDS) and neurodegeneration with brain iron accumulation (NBIA) to determine whether it would identify altered metabolism and hence constitute a potentially useful 'biomarker' indicating functional disturbances associated with dystonia and severity of the disease. A total of 27 children (15 PDS and 12 NBIA) underwent brain ¹⁸F-FDG PET/CT imaging under anaesthesia during acquisition. The images were assessed visually and the two groups were compared quantitatively with statistical parametric mapping. PET/CT images were spatially transformed to Montreal Neurological Institute standard space. Voxelwise ¹⁸F-FDG uptake was normalized to whole-brain uptake. Data of both groups were correlated separately with duration and severity of dystonia as assessed using the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS). Visual inspection did not identify any abnormalities in ¹⁸F-FDG uptake within the cerebral cortex, basal ganglia, or thalami in either group. Quantitative analysis identified higher uptake in the posterior cingulate and bilateral posterior putamina but decreased uptake in the occipital cortex and cerebellum in NBIA compared with PDS. The NBIA group had more severe dystonia scores compared with the PDS group. BFMDRS was negatively correlated with age but not with duration of dystonia. Compared with PDS, NBIA is dominated by relative overactivity in the putamen and by cerebellar underactivity, patterns that may reflect the increased severity of dystonia in NBIA cases. Hence, there is a potential role for ¹⁸F-FDG PET/CT imaging in paediatric dystonia, particularly in the NBIA group.

  7. A follow-up ¹⁸F-FDG brain PET study in a case of Hashimoto's encephalopathy causing drug-resistant status epilepticus treated with plasmapheresis.

    PubMed

    Pari, Elisa; Rinaldi, Fabrizio; Premi, Enrico; Codella, Maria; Rao, Renata; Paghera, Barbara; Panarotto, Maria Beatrice; De Maria, Giovanni; Padovani, Alessandro

    2014-04-01

    Hashimoto's encephalopathy (HE) is a rare neuropsychiatric syndrome associated with antithyroid antibodies. It may have an acute onset (episodes of cerebral ischemia, seizure, and psychosis) or it may present as an indolent form (depression, cognitive decline, myoclonus, tremors, and fluctuations in level of consciousness). We here describe a case of encephalopathy presenting as non-convulsive status epilepticus associated with Hashimoto's thyroiditis (HT), unresponsive to corticosteroid therapy, with improvement after plasma exchange treatment. A previously healthy 19-year-old woman, presented generalized tonic-clonic seizures. About a month later, she manifested a speech disorder characterized by difficulties in the production and comprehension of language. Within a few days she also developed confusion and difficulties in recognizing familiar places, with gradual worsening over time. EEG revealed a non-convulsive status epilepticus (NCSE). CSF examination showed slightly elevated cell count and four oligoclonal bands. MRI was unremarkable, and (18)F-FDG brain PET showed widespread hypometabolism, mostly in posterior regions bilaterally. Laboratory and ultrasound findings showed signs of HT. Treatment with steroid was introduced without any improvement. After five sessions of plasma exchange there was a decrease of antithyroid antibodies, as well as EEG and clinical improvement. Three months after discharge (18)F-FDG brain PET showed a complete normalization of the picture, and the patient was asymptomatic. This report emphasizes the successful treatment of HE with plasma exchange in a patient who presented with NCSE. Based on the actual evidence, the term "Encephalopathy associated with Hashimoto's thyroiditis" may be the most proper. Furthermore, to our knowledge, this is the first case of an adult patient studied twice with an (18)F-FDG brain PET: prior to treatment with plasma exchange, and at 3 months follow-up when the patient was clinically completely

  8. Performance evaluation of a high-resolution brain PET scanner using four-layer MPPC DOI detectors

    NASA Astrophysics Data System (ADS)

    Watanabe, Mitsuo; Saito, Akinori; Isobe, Takashi; Ote, Kibo; Yamada, Ryoko; Moriya, Takahiro; Omura, Tomohide

    2017-09-01

    A high-resolution positron emission tomography (PET) scanner, dedicated to brain studies, was developed and its performance was evaluated. A four-layer depth of interaction detector was designed containing five detector units axially lined up per layer board. Each of the detector units consists of a finely segmented (1.2 mm) LYSO scintillator array and an 8  ×  8 array of multi-pixel photon counters. Each detector layer has independent front-end and signal processing circuits, and the four detector layers are assembled as a detector module. The new scanner was designed to form a detector ring of 430 mm diameter with 32 detector modules and 168 detector rings with a 1.2 mm pitch. The total crystal number is 655 360. The transaxial and axial field of views (FOVs) are 330 mm in diameter and 201.6 mm, respectively, which are sufficient to measure a whole human brain. The single-event data generated at each detector module were transferred to the data acquisition servers through optical fiber cables. The single-event data from all detector modules were merged and processed to create coincidence event data in on-the-fly software in the data acquisition servers. For image reconstruction, the high-resolution mode (HR-mode) used a 1.2 mm2 crystal segment size and the high-speed mode (HS-mode) used a 4.8 mm2 size by collecting 16 crystal segments of 1.2 mm each to reduce the computational cost. The performance of the brain PET scanner was evaluated. For the intrinsic spatial resolution of the detector module, coincidence response functions of the detector module pair, which faced each other at various angles, were measured by scanning a 0.25 mm diameter 22Na point source. The intrinsic resolutions were obtained with 1.08 mm full width at half-maximum (FWHM) and 1.25 mm FWHM on average at 0 and 22.5 degrees in the first layer pair, respectively. The system spatial resolutions were less than 1.0 mm FWHM throughout the whole FOV, using a

  9. Brain metabolic changes associated with predispotion to onset of major depressive disorder and adjustment disorder in cancer patients--a preliminary PET study.

    PubMed

    Kumano, H; Ida, I; Oshima, A; Takahashi, K; Yuuki, N; Amanuma, M; Oriuchi, N; Endo, K; Matsuda, H; Mikuni, M

    2007-10-01

    To explore neurobiological risk factors for major depressive disorder (MDD) and adjustment disorder in cancer patients by examining regional brain metabolism before psychiatric manifestation using positron emission tomography and by prospectively observing depressive and anxiety symptoms. Cancer patients who showed no psychiatric symptoms when they underwent 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) were followed up for one year using the Hospital Anxiety and Depression Scale (HADS). Fourteen patients who showed high HADS scores and 14 patients who showed low HADS scores were assessed by a psychiatrist 2 years after the PET scan and grouped into the deterioration group (n=10) and the no-change group (n=9). 18F-FDG PET images were analyzed to examine the difference in local brain glucose metabolism between the two groups. The deterioration group showed a decreased glucose metabolism in the right medial frontal gyrus (BA6) and an increased glucose metabolism in the right posterior cingulate (BA29), right anterior cingulate (BA25), left subcallosal gyrus (BA25), and left caudate compared with the no-change group. Cancer patients who later developed MDD or adjustment disorder showed regional brain metabolic changes. These regions may be associated with vulnerability to the onset of MDD or adjustment disorder in cancer patients.

  10. Effectiveness of the addition of the brain region to the FDG-PET/CT imaging area in patients with suspected or diagnosed lung cancer.

    PubMed

    Tasdemir, Bekir; Urakci, Zuhat; Dostbil, Zeki; Unal, Kemal; Simsek, F Selcuk; Teke, Fatma; Goya, Cemil

    2016-03-01

    We aimed to evaluate the effectiveness of the brain region imaging in FDG-PET/CT scanning of patients with suspected or diagnosed lung cancer. We performed the study retrospectively on the medical charts of 427 patients. We divided the FDG-PET/CT field of view (FOV) into four major imaging regions: brain, head-neck, abdomen and pelvis. Metastatic findings on these regions were checked and determined the potential of these findings to affect the chemotherapy or radiotherapy protocol or surgical management. If metastatic findings had a potential to modify these parameters, we named this situation as "clinical contribution". Considering the number of bed positions of these regions, we calculated the clinical contribution of each region and named as "effective clinical contribution". Then, we calculated the metastatic findings, clinical contribution, and effective clinical contribution ratios. We found different brain metastasis ratios for lung cancer, solitary pulmonary mass (SPM), and solitary pulmonary nodule (SPN) groups (8.7, 2.8 and 0.9 %, respectively). In addition, the clinical contribution and effective clinical contribution ratios in the brain region for these three groups were 6.4, 2.8, 0.0 and 6.4, 2.8, 0.0 %, respectively. The highest metastatic findings (30.6 %) and clinical contribution (9.8 %) ratios were found in the abdomen region of the lung cancer group. However, the highest effective clinical contribution ratio (6.8 %) was found in the brain region within the same group. The addition of the brain region to the limited whole-body FOV in FDG-PET/CT scanning seems to be effective in the lung cancer and SPM groups, but not in the SPN group.

  11. Central pulse pressure is a determinant of heart and brain remodeling in the elderly: a quantitative MRI and PET pilot study.

    PubMed

    Verger, Antoine; van der Gucht, Axel; Guedj, Eric; Marie, Pierre-Yves; Hossu, Gabriela; Mandry, Damien; Morel, Olivier; Perrin, Mathieu; Fay, Renaud; Benetos, Athanase; Joly, Laure

    2015-07-01

    The sustained elevation of blood pressure (BP) and especially of central pulse pressure (cPP) leads to heart and brain damage. This pilot study was aimed to precise the relationships between peripheral and central BP levels, and the remodeling of heart and brain as objectively quantified by cardiac MRI and brain F-fluorodeoxyglucose (FDG)-PET imaging in the elderly. Twenty-eight apparently healthy elderly individuals (66-85 years old, 14 women) were prospectively recruited and allocated into two half groups, one with and one without hypertension, and all were referred for the quantitative determinations of peripheral and central BP using applanation tonometry, indexed left ventricular mass (per m of body surface area) using cardiac MRI, and brain metabolism with a voxel-based analysis of FDG-PET images adjusted for age and sex. Indexed left ventricular mass, reflecting cardiac remodeling, was correlated with the overall pressure variables involving both peripheral and central levels of systolic and pulse pressure (all P ≤ 0.001). By contrast, brain metabolism was significantly correlated with only cPP (P < 0.02). A cPP of at least 50  mmHg was associated with both a lower metabolism in frontal areas (P = 0.005) and a higher indexed left ventricular mass (P = 0.03). This pilot study suggests that, when quantified by MRI and PET imaging, left ventricular mass and brain metabolism of elderly individuals are related to the cPP and to the 50  mmHg threshold, corresponding to what has previously been documented for the risk of cardiovascular event.

  12. F18 EF5 PET/CT Imaging in Patients with Brain Metastases from Breast Cancer

    DTIC Science & Technology

    2012-07-01

    patients are offered gamma knife radiotherapy upfront rather than whole brain radiotherapy which has impacted our accrual rates. Additionally, though we...status often receive upfront gamma knife radiotherapy instead which currently those patients are excluded from the study. To address these challenges...treatment. Additionally, opening up the protocol enrollment to include patients receiving gamma knife radiotherapy has also been considered. Including

  13. F18 EF5 PET/CT Imaging in Patients with Brain Metastases from Breast Cancer

    DTIC Science & Technology

    2014-09-01

    Pennsylvania, where more patients are offered gamma knife radiotherapy upfront rather than whole brain radiotherapy which has impacted our accrual rates...to follow. Furthermore, patients with better performance status often receive upfront gamma knife radiotherapy instead. These patients were...four weeks post treatment. Additionally, opening up the protocol enrollment to include patients receiving gamma knife radiotherapy was done

  14. SELF-REPORTED MEMORY IMPAIRMENT AND BRAIN PET OF AMYLOID AND TAU IN NON-DEMENTED MIDDLE-AGED AND OLDER ADULTS

    PubMed Central

    Siddarth, Prabha; Saito, Nathan Y.; Ercoli, Linda M.; Burggren, Alison C.; Kepe, Vladimir; Lavretsky, Helen; Miller, Karen J.; Kim, Jeanne; Huang, S. C.; Bookheimer, Susan Y.; Barrio, Jorge R.; Small, Gary W.

    2012-01-01

    Background Whether perceived changes in memory parallel changes in brain pathology is uncertain. Positron emission tomography (PET) scans using 2-(1-{6-[(2-[F-18]fluoroethyl)(methyl)amino]-2-naphthyl}ethylidene)malononitrile (FDDNP) can measure levels of amyloid plaques and tau neurofibrillary tangles in vivo. Here we investigate whether degree of self-reported memory impairment is associated with FDDNP-PET binding levels in persons without dementia. Methods 57 middle-aged and older adults without dementia (mean age [±SD] = 66.3±10.6 years), including 25 with normal aging and 32 with mild cognitive impairment (MCI), were assessed. The outcome measures were the four factor scores of the Memory Functioning Questionnaire (MFQ) (frequency of forgetting, seriousness of forgetting, retrospective functioning, and mnemonics use) and FDDNP-PET binding levels in medial temporal, lateral temporal, posterior cingulate, parietal, frontal, and global (overall average) regions of interest. Results After controlling for age, higher reported frequency of forgetting was associated with greater medial temporal (r = −0.29, p = 0.05), parietal (r = −0.30, p =.03), frontal (r = −0.35, p = 0.01) and global FDDNP-PET binding levels (r = −0.33, p = .02). The remaining MFQ factor scores were not significantly associated with FDDNP-PET binding levels, and no significant differences were found between normal aging and MCI subjects. Item analysis of the frequency of forgetting factor revealed 5 questions that yielded similar results as the full 32 question scale (r = −0.52, p = .0002). Conclusions These findings suggest that some forms of memory self-awareness, in particular the reported frequency of forgetting, may reflect extent of cerebral amyloid and tau brain pathology. PMID:22335970

  15. STRATEGIES FOR QUANTIFYING PET IMAGING DATA FROM TRACER STUDIES OF BRAIN RECEPTORS AND ENZYMES.

    SciTech Connect

    Logan, J.

    2001-04-02

    A description of some of the methods used in neuroreceptor imaging to distinguish changes in receptor availability has been presented in this chapter. It is necessary to look beyond regional uptake of the tracer since uptake generally is affected by factors other than the number of receptors for which the tracer has affinity. An exception is the infusion method producing an equilibrium state. The techniques vary in complexity some requiring arterial blood measurements of unmetabolized tracer and multiple time uptake data. Others require only a few plasma and uptake measurements and those based on a reference region require no plasma measurements. We have outlined some of the limitations of the different methods. Laruelle (1999) has pointed out that test/retest studies to which various methods can be applied are crucial in determining the optimal method for a particular study. The choice of method will also depend upon the application. In a clinical setting, methods not involving arterial blood sampling are generally preferred. In the future techniques for externally measuring arterial plasma radioactivity with only a few blood samples for metabolite correction will extend the modeling options of clinical PET. Also since parametric images can provide information beyond that of ROI analysis, improved techniques for generating such images will be important, particularly for ligands requiring more than a one-compartment model. Techniques such as the wavelet transform proposed by Turkheimer et al. (2000) may prove to be important in reducing noise and improving quantitation.

  16. Development of a High Precision Axial 3-D PET for Brain Imaging

    NASA Astrophysics Data System (ADS)

    Bolle, E.; Braem, A.; Casella, C.; Chesi, E.; Clinthorne, N.; Cochran, E.; De Leo, R.; Dissertori, G.; Djambazov, L.; Honscheid, K.; Huh, S.; Johnson, I.; Joram, C.; Kagan, H.; Lacasta, C.; Lustermann, W.; Meddi, F.; Nappi, E.; Nessi-Tedaldi, F.; Oliver, J. F.; Pauss, F.; Rafecas, M.; Renker, D.; Rudge, A.; Schinzel, D.; Schneider, T.; Séguinot, J.; Smith, S.; Solevi, P.; Stapnes, S.; Vilardi, I.; Weilhammer, P.

    2009-12-01

    We describe a PET device based on a novel method to extract the coordinates of the interaction point of the 511keV γ rays from 100 mm long and thin LYSO (Lutetium Yttrium OxyorthoSilicate) scintillator bars, positioned axially in the tomograph. The coordinate along the hit crystal is measured by using a hodoscope of Wave Length Shifting (WLS) plastic strips mounted perpendicularly to each plane of scintillators. As photodetectors, new Geiger mode Avalanche PhotoDetectors (G-APDs) with integrated electronics are being used to detect both the hit crystal in a block (x and y coordinates) and the interaction point in the crystal (z coordinate) through the light escaping from the crystal and transmitted to the WLS strips. In this way, the γ interaction point can be determined with a spatial resolution of few cubic millimeters down to a minimum deposited energy of about 50 keV, resulting in a volumetric precision very close to the limits imposed by the physics of the positron annihilation. The method allows to increase the detection efficiency without affecting the spatial resolution by adding scintillator planes in the radial direction. A demonstrator scanner, based on two matrices of 8 × 6 LYS crystals and 312 WLS strips, slotted in between the crystals, is under construction. Preliminary results from the feasibility studies of the various components will be presented.

  17. Unique Distribution of Aromatase in the Human Brain: In Vivo Studies With PET and [N-Methyl-11C]Vorozole

    SciTech Connect

    Biegon, A.; Biegon, A.; Kim, S.W.; Alexoff, D.; Millard, J.; Carter, P.; Hubbard, B.; King, P.; Logan, J.; Muench, L.; Pareto, D.; Schlyer, D.; Shea, C.; Telang, F.; Wang, G.-J.; Xu, Y.; Fowler, J.

    2010-10-01

    Aromatase catalyzes the last step in estrogen biosynthesis. Brain aromatase is involved in diverse neurophysiological and behavioral functions including sexual behavior, aggression, cognition, and neuroprotection. Using positron emission tomography (PET) with the radiolabeled aromatase inhibitor [N-methyl-{sup 11}C]vorozole, we characterized the tracer distribution and kinetics in the living human brain. Six young, healthy subjects, three men and three women, were administered the radiotracer alone on two separate occasions. Women were scanned in distinct phases of the menstrual cycle. Specificity was confirmed by pretreatment with a pharmacological (2.5 mg) dose of the aromatase inhibitor letrozole. PET data were acquired over a 90-min period and regions of interest placed over selected brain regions. Brain and plasma time activity curves, corrected for metabolites, were used to derive kinetic parameters. Distribution volume (V{sub T}) values in both men and women followed the following rank order: thalamus > amygdala = preoptic area > medulla (inferior olive) > accumbens, pons, occipital and temporal cortex, putamen, cerebellum, and white matter. Pretreatment with letrozole reduced VT in all regions, though the size of the reduction was region-dependent, ranging from {approx}70% blocking in thalamus andpreoptic area to {approx}10% in cerebellum. The high levels of aromatase in thalamus and medulla (inferior olive) appear to be unique to humans. These studies set the stage for the noninvasive assessment of aromatase involvement in various physiological and pathological processes affecting the human brain.

  18. Unique distribution of aromatase in the human brain: in vivo studies with PET and [N-methyl-11C]vorozole

    PubMed Central

    Biegon, Anat; Kim, Sung Won; Alexoff, David L.; Jayne, Millard; Carter, Pauline; Hubbard, Barbara; King, Payton; Logan, Jean; Muench, Lisa; Pareto, Deborah; Schlyer, David; Shea, Colleen; Telang, Frank; Wang, Gene-Jack; Xu, Youwen; Fowler, Joanna S.

    2010-01-01

    Aromatase catalyzes the last step in estrogen biosynthesis. Brain aromatase is involved in diverse neurophysiological and behavioral functions including sexual behavior, aggression, cognition and neuroprotection. Using positron emission tomography (PET) with the radiolabeled aromatase inhibitor [N-methyl-11C]vorozole, we characterized the tracer distribution and kinetics in the living human brain. Six young, healthy subjects, 3 men and 3 women, were administered the radiotracer alone on two separate occasions. Women were scanned in distinct phases of the menstrual cycle. Specificity was confirmed by pretreatment with a pharmacological (2.5mg) dose of the aromatase inhibitor letrozole. PET data were acquired over a 90 min period and regions of interest placed over selected brain regions. Brain and plasma time activity curves, corrected for metabolites, were used to derive kinetic parameters. Distribution volume (VT) values in both men and women followed the rank order: thalamus>amygdala=preoptic area>medulla(inferior olive) > accumbens, pons, occipital and temporal cortex, putamen, cerebellum and white matter. Pretreatment with letrozole reduced VT in all regions, though the size of the reduction was region dependent; ranging from ~70% blocking in thalamus and preoptic area to ~10% in cerebellum. The high levels of aromatase in thalamus and medulla (inferior olive) appear to be unique to humans. These studies set the stage for the non-invasive assessment of aromatase involvement in various physiological and pathological processes affecting the human brain. PMID:20842717

  19. PET and SPECT exploration of central monoaminergic transporters for the development of new drugs and treatments in brain disorders.

    PubMed

    Guilloteau, D; Chalon, S

    2005-01-01

    Membrane and vesicular monoaminergic transporters, responsible for the homeostasis of neurotransmitter pools at nerve endings, are very involved in the physiology and diseases of central nervous system. Recent progresses of cerebral molecular imaging using SPECT and PET methods allow the extend of in vivo exploration of these transporters. For this aim, an increasing number of radiopharmaceuticals labelled with [123I], [99mTc], [11C] or [18F] have been developed such as cocaine derivatives for the DAT, compounds from the diphenyl sulfide family for the SERT, and dihydrotetrabenazine derivatives for the VMAT2. These functional imaging methods can be very useful in several neurological and psychiatric disorders which involve the monoaminergic neurotransmission systems such as Parkinson's disease, ADHD, depression and autism. For example, the DAT is a specific index of the density of dopaminergic endings which progressively degenerate in Parkinson's disease. In vivo exploration of this transporter can therefore be a relevant way (i) to realize an early detection of the loss of dopaminergic neurons, (ii) to assess the progression of the disease, (iii) to validate and improve the efficacy of new therapeutic strategies such as neuroprotection and neuroreparation. In all, the extend of in vivo exploration of monoamine transporters will allow great progress for (1) knowledge of physiopathological mechanisms of brain disorders, (2) early diagnosis of cerebral dysfunctions, allowing early use of new therapies, (3) selection of homogenous classes of subjects for therapeutic assays, (4) objectiveness of drug-molecular target interaction, (5) follow-up of disease evolution and treatment.

  20. RatCAP: a small, head-mounted PET tomograph for imaging the brain of an awake RAT

    NASA Astrophysics Data System (ADS)

    Woody, C.; Kriplani, A.; O'Connor, P.; Pratte, J.-F.; Radeka, V.; Rescia, S.; Schlyer, D.; Shokouhi, S.; Stoll, S.; Vaska, P.; Villaneuva, A.; Volkow, N.; Yu, B.

    2004-07-01

    A small, head-mounted tomograph is being developed which will allow PET imaging of the brain of an awake rat. This device will permit neurophysiological studies to be carried out on small animals without the use of anaesthesia, which severely suppresses brain functions and behavior. The tomograph consists of a 4 cm diameter ring consisting of 12 blocks of LSO crystals, each containing a 4×8 matrix of 2×2 mm 2 pixels read out with a Hamamatsu S8550 avalanche photodiode array. The ring will be mounted to the head of the rat and supported by a tether that carries the weight and provides a pathway for electrical signals. Combined with additional mechanical components, it will allow nearly complete freedom of movement of the animal. In order to minimize the weight of the ring, and to keep all of the front end readout electronics as close as possible to the detector, a new ASIC is being developed in 0.18 μm CMOS technology that will process the analog signals and provide digital readout of the pixel arrays and timing information. This paper will describe the novel features and challenges of this new detector, along with preliminary results obtained with a pair of block detectors used in a configuration similar to the final tomograph. Results are given on studies carried out to optimize the light output of the crystal arrays, measurements of the APDs, a preliminary design of the readout electronics chip, and reconstructed images of various types of phantoms in order to demonstrate the feasibility of the detector concept.

  1. A critical period of brain development: studies of cerebral glucose utilization with PET.

    PubMed

    Chugani, H T

    1998-01-01

    Studies with positron emission tomography indicate that the human brain undergoes a period of postnatal maturation that is much more protracted than previously suspected. In the newborn, the highest degree of glucose metabolism (representative of functional activity) is in primary sensory and motor cortex, cingulate cortex, thalamus, brain stem, cerebellar vermis, and hippocampal region. At 2 to 3 months of age, glucose utilization increases in the parietal, temporal, and primary visual cortex; basal ganglia; and cerebellar hemispheres. Between 6 and 12 months, glucose utilization increases in frontal cortex. These metabolic changes correspond to the emergence of various behaviors during the first year of life. The measurement of absolute rates of glucose utilization during development indicates that the cerebral cortex undergoes a dynamic course of metabolic maturation that persists until ages 16-18 years. Initially, there is a rise in the rates of glucose utilization from birth until about age 4 years, at which time the child's cerebral cortex uses over twice as much glucose as that of adults. From age 4 to 10 years, these very high rates of glucose consumption are maintained, and only after then is there a gradual decline of glucose metabolic rates to reach adult values by age 16-18 years. Correlations between glucose utilization rates and synaptogenesis are discussed, and the argument is made that these findings have important implications with respect to human brain plasticity following injury as well as to "critical periods" of maximal learning capacity.

  2. An Interindividual Comparison of O-(2- [{sup 18}F]Fluoroethyl)-L-Tyrosine (FET)- and L-[Methyl-{sup 11}C]Methionine (MET)-PET in Patients With Brain Gliomas and Metastases

    SciTech Connect

    Grosu, Anca-Ligia; Astner, Sabrina T.; Riedel, Eva; Nieder, Carsten; Wiedenmann, Nicole; Heinemann, Felix; Schwaiger, Markus; and others

    2011-11-15

    Purpose: L-[methyl-{sup 11}C]methionine (MET)-positron emission tomography (PET) has a high sensitivity and specificity for imaging of gliomas and metastatic brain tumors. The short half-life of {sup 11}C (20 minutes) limits the use of MET-PET to institutions with onsite cyclotron. O-(2- [{sup 18}F]fluoroethyl)-L-tyrosine (FET) is labeled with {sup 18}F (half-life, 120 minutes) and could be used much more broadly. This study compares the uptake of FET and MET in gliomas and metastases, as well as treatment-induced changes. Furthermore, it evaluates the gross tumor volume (GTV) of gliomas defined on PET and magnetic resonance imaging (MRI). Methods and Materials: We examined 42 patients with pretreated gliomas (29 patients) or brain metastases (13 patients) prospectively by FET- and MET-PET on the same day. Uptake of FET and MET was quantified by standardized uptake values. Imaging contrast was assessed by calculating lesion-to-gray matter ratios. Tumor extension was quantified by contouring GTV in 17 patients with brain gliomas. Gross tumor volume on PET was compared with GTV on MRI. Sensitivity and specificity of MET- and FET-PET for differentiation of viable tumor from benign changes were evaluated by comparing the PET result with histology or clinical follow-up. Results: There was a strong linear correlation between standardized uptake values calculated for both tracers in cortex and lesions: r = 0.78 (p = 0.001) and r = 0.84 (p < 0.001), respectively. Image contrast was similar for MET- and FET-PET (lesion-to-gray matter ratios of 2.36 {+-} 1.01 and 2.33 {+-} 0.77, respectively). Mean GTV in 17 glioma patients was not significantly different on MET- and FET-PET. Both MET- and FET-PET delineated tumor tissue outside of MRI changes. Both tracers provided differentiated tumor tissue and treatment-related changes with a sensitivity of 91% at a specificity of 100%. Conclusions: O-(2- [{sup 18}F]fluoroethyl)-L-tyrosine-PET and MET-PET provide comparable diagnostic

  3. Unexpectedly high affinity of a novel histamine H3 receptor antagonist, GSK239512, in vivo in human brain, determined using PET

    PubMed Central

    Ashworth, S; Berges, A; Rabiner, E A; Wilson, A A; Comley, R A; Lai, R Y K; Boardley, R; Searle, G; Gunn, R N; Laruelle, M; Cunningham, V J

    2014-01-01

    BACKGROUND AND PURPOSE This study aimed to investigate the relationship between the plasma concentration (PK) of the novel histamine H3 receptor antagonist, GSK239512, and the brain occupancy of H3 receptors (RO) in healthy human volunteers. EXPERIMENTAL APPROACH PET scans were obtained after i.v. administration of the H3-specific radioligand [11C]GSK189254. Each subject was scanned before and after single oral doses of GSK239512, at 4 and 24 h after dose. PET data were analysed by compartmental analysis, and regional RO estimates were obtained by graphical analysis of changes in the total volumes of distribution of the radioligand, followed by a correction for occupancy by the high affinity radioligand. The PK/RO relationship was analysed by a population-modelling approach, using the average PK of GSK239512 during each scan. KEY RESULTS Following administration of GSK239512, there was a reduction in the brain uptake of [11C]GSK189254 in all regions, including cerebellum. RO at 4 h was higher than at 24 h, and the PK/RO model estimated a PK associated with 50% of RO of 0.0068 ng·mL−1. This corresponds to a free concentration of 4.50 × 10−12 M (pK = 11.3). CONCLUSIONS AND IMPLICATIONS The affinity of GSK239512 for brain H3 receptors in humans in vivo is much higher than that expected from studies in vitro, and higher than that observed in PET studies in pigs. The study illustrates the utility of carrying out PET studies in humans early in drug development, providing accurate quantification of GSK239512 RO in vivo as a function of time and dose. PMID:24670146

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

    PubMed

    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.

  5. Bias in iterative reconstruction of low-statistics PET data: benefits of a resolution model

    NASA Astrophysics Data System (ADS)

    Walker, M. D.; Asselin, M.-C.; Julyan, P. J.; Feldmann, M.; Talbot, P. S.; Jones, T.; Matthews, J. C.

    2011-02-01

    Iterative image reconstruction methods such as ordered-subset expectation maximization (OSEM) are widely used in PET. Reconstructions via OSEM are however reported to be biased for low-count data. We investigated this and considered the impact for dynamic PET. Patient listmode data were acquired in [11C]DASB and [15O]H2O scans on the HRRT brain PET scanner. These data were subsampled to create many independent, low-count replicates. The data were reconstructed and the images from low-count data were compared to the high-count originals (from the same reconstruction method). This comparison enabled low-statistics bias to be calculated for the given reconstruction, as a function of the noise-equivalent counts (NEC). Two iterative reconstruction methods were tested, one with and one without an image-based resolution model (RM). Significant bias was observed when reconstructing data of low statistical quality, for both subsampled human and simulated data. For human data, this bias was substantially reduced by including a RM. For [11C]DASB the low-statistics bias in the caudate head at 1.7 M NEC (approx. 30 s) was -5.5% and -13% with and without RM, respectively. We predicted biases in the binding potential of -4% and -10%. For quantification of cerebral blood flow for the whole-brain grey- or white-matter, using [15O]H2O and the PET autoradiographic method, a low-statistics bias of <2.5% and <4% was predicted for reconstruction with and without the RM. The use of a resolution model reduces low-statistics bias and can hence be beneficial for quantitative dynamic PET.

  6. Synthesis of (R)- and (S)-[C-11]L-365,260 for PET studies of brain cholecystokinin (CCK) receptors

    SciTech Connect

    Haradahira, T.; Suzuki, K.; Inoue, O.

    1994-05-01

    Cholecystokinin (CCK) is a recognized peptide hormone in the gut and proposed as a neurotransmitter or neuromodulator in the central nervous system. Two distinct CCK receptors termed CCK-A and CCK-B have been characterized. CCK-A receptor is primarily distributed in the peripheral tissues including pancreas and gallbladder and also known to be distributed in a few brain regions. CCK-B receptor is widely distributed in the brain and has been proposed to be involved in anxiety, satiety and nociception. To investigate the functional roles of the CCK receptors in the brain by positron emission tomography, we have synthesized an enantiomeric pair of C-11 labeled non-peptide antagonists against the CCK receptors. L-365,260 [3R(+)-N-(2,3-dihydro-1-methyl-2-oxo-5-phenyl-1H-1,4-benzodiazepine-3-yl)-N`-(3-methylpheny lurea)] is a potent CCK-B selective non-peptide antagonist (CCK-A/CCK-B ratio of IC50, 140), whereas its (S)-enantiomer is selective toward CCK-A receptor (CCK-A/CCK-B ratio of IC50, 0.02). We have synthesized the (R)- and (S)-enantiomers of [C-11]-365,260 by N-methylation (50{degrees}C for 5 min) of the racemic desmethyl precursor with [C-11]iodomethane using sodium hydride as a base and subsequent optical resolution with HPLC (column: ChiraSpher, 250 x 10 mm, Merck; eluent: n-hexane / 1,4-dioxane / 2-propanol / triethylamine = 70 / 25 / 5 / 0.1). Radiochemical yields (decay corrected) and optical purities were 34%, 99% for R-enantiomer and 36%, 99% for S-enantiomer, respectively. The total synthesis time was 40 min and specific activity was about 37 GBq/{mu}mol. In PET studies on rhesus monkey (R)-enantiomer showed a high uptake of radioactivity in the cerebral cortex, region known to have a high concentration of CCK-B receptor.

  7. Changes of Brain Glucose Metabolism in the Pretreatment Patients with Non-Small Cell Lung Cancer: A Retrospective PET/CT Study.

    PubMed

    Zhang, Weishan; Ning, Ning; Li, Xianjun; Niu, Gang; Bai, Lijun; Guo, Youmin; Yang, Jian

    2016-01-01

    The tumor-to-brain communication has been emphasized by recent converging evidences. This study aimed to compare the difference of brain glucose metabolism between patients with non-small cell lung cancer (NSCLC) and control subjects. NSCLC patients prior to oncotherapy and control subjects without malignancy confirmed by 6 months follow-up were collected and underwent the resting state 18F-fluoro-D-glucose (FDG) PET/CT. Normalized FDG metabolism was calculated by a signal intensity ratio of each brain region to whole brain. Brain glucose metabolism was compared between NSCLC patients and control group using two samples t-test and multivariate test by statistical parametric maps (SPM) software. Compared with the control subjects (n = 76), both brain glucose hyper- and hypometabolism regions with significant statistical differences (P<0.01) were found in the NSCLC patients (n = 83). The hypermetabolism regions (bilateral insula, putamen, pallidum, thalamus, hippocampus and amygdala, the right side of cerebellum, orbital part of right inferior frontal gyrus and vermis) were component parts of visceral to brain signal transduction pathways, and the hypometabolism regions (the left superior parietal lobule, bilateral inferior parietal lobule and left fusiform gyrus) lied in dorsal attention network and visuospatial function areas. The changes of brain glucose metabolism exist in NSCLC patients prior to oncotherapy, which might be attributed to lung-cancer related visceral sympathetic activation and decrease of dorsal attention network function.

  8. Changes of Brain Glucose Metabolism in the Pretreatment Patients with Non-Small Cell Lung Cancer: A Retrospective PET/CT Study

    PubMed Central

    Zhang, Weishan; Ning, Ning; Li, Xianjun; Niu, Gang; Bai, Lijun; Guo, Youmin; Yang, Jian

    2016-01-01

    Objective The tumor-to-brain communication has been emphasized by recent converging evidences. This study aimed to compare the difference of brain glucose metabolism between patients with non-small cell lung cancer (NSCLC) and control subjects. Methods NSCLC patients prior to oncotherapy and control subjects without malignancy confirmed by 6 months follow-up were collected and underwent the resting state 18F-fluoro-D-glucose (FDG) PET/CT. Normalized FDG metabolism was calculated by a signal intensity ratio of each brain region to whole brain. Brain glucose metabolism was compared between NSCLC patients and control group using two samples t-test and multivariate test by statistical parametric maps (SPM) software. Results Compared with the control subjects (n = 76), both brain glucose hyper- and hypometabolism regions with significant statistical differences (P<0.01) were found in the NSCLC patients (n = 83). The hypermetabolism regions (bilateral insula, putamen, pallidum, thalamus, hippocampus and amygdala, the right side of cerebellum, orbital part of right inferior frontal gyrus and vermis) were component parts of visceral to brain signal transduction pathways, and the hypometabolism regions (the left superior parietal lobule, bilateral inferior parietal lobule and left fusiform gyrus) lied in dorsal attention network and visuospatial function areas. Conclusions The changes of brain glucose metabolism exist in NSCLC patients prior to oncotherapy, which might be attributed to lung-cancer related visceral sympathetic activation and decrease of dorsal attention network function. PMID:27529342

  9. Automated quantification of 18F-flutemetamol PET activity for categorizing scans as negative or positive for brain amyloid: concordance with visual image reads.

    PubMed

    Thurfjell, Lennart; Lilja, Johan; Lundqvist, Roger; Buckley, Chris; Smith, Adrian; Vandenberghe, Rik; Sherwin, Paul

    2014-10-01

    Clinical trials of the PET amyloid imaging agent (18)F-flutemetamol have used visual assessment to classify PET scans as negative or positive for brain amyloid. However, quantification provides additional information about regional and global tracer uptake and may have utility for image assessment over time and across different centers. Using postmortem brain neuritic plaque density data as a truth standard to derive a standardized uptake value ratio (SUVR) threshold, we assessed a fully automated quantification method comparing visual and quantitative scan categorizations. We also compared the histopathology-derived SUVR threshold with one derived from healthy controls. Data from 345 consenting subjects enrolled in 8 prior clinical trials of (18)F-flutemetamol injection were used. We grouped subjects into 3 cohorts: an autopsy cohort (n = 68) comprising terminally ill patients with postmortem confirmation of brain amyloid status; a test cohort (n = 172) comprising 33 patients with clinically probable Alzheimer disease, 80 patients with mild cognitive impairment, and 59 healthy volunteers; and a healthy cohort of 105 volunteers, used to define a reference range for SUVR. Visual image categorizations for comparison were from a previous study. A fully automated PET-only quantification method was used to compute regional neocortical SUVRs that were combined into a single composite SUVR. An SUVR threshold for classifying scans as positive or negative was derived by ranking the PET scans from the autopsy cohort based on their composite SUVR and comparing data with the standard of truth based on postmortem brain amyloid status for subjects in the autopsy cohort. The derived threshold was used to categorize the 172 scans in the test cohort as negative or positive, and results were compared with categorization using visual assessment. Different reference and composite region definitions were assessed. Threshold levels were also compared with corresponding thresholds

  10. Glucose Metabolic Changes in the Brain and Muscles of Patients with Nonspecific Neck Pain Treated by Spinal Manipulation Therapy: A [18F]FDG PET Study

    PubMed Central

    Inami, Akie; Ogura, Takeshi; Watanuki, Shoichi; Masud, Md. Mehedi; Shibuya, Katsuhiko; Miyake, Masayasu; Matsuda, Rin; Hiraoka, Kotaro; Itoh, Masatoshi; Fuhr, Arlan W.; Yanai, Kazuhiko

    2017-01-01

    Objective. The aim of this study was to investigate changes in brain and muscle glucose metabolism that are not yet known, using positron emission tomography with [18F]fluorodeoxyglucose ([18F]FDG PET). Methods. Twenty-one male volunteers were recruited for the present study. [18F]FDG PET scanning was performed twice on each subject: once after the spinal manipulation therapy (SMT) intervention (treatment condition) and once after resting (control condition). We performed the SMT intervention using an adjustment device. Glucose metabolism of the brain and skeletal muscles was measured and compared between the two conditions. In addition, we measured salivary amylase level as an index of autonomic nervous system (ANS) activity, as well as muscle tension and subjective pain intensity in each subject. Results. Changes in brain activity after SMT included activation of the dorsal anterior cingulate cortex, cerebellar vermis, and somatosensory association cortex and deactivation of the prefrontal cortex and temporal sites. Glucose uptake in skeletal muscles showed a trend toward decreased metabolism after SMT, although the difference was not significant. Other measurements indicated relaxation of cervical muscle tension, decrease in salivary amylase level (suppression of sympathetic nerve activity), and pain relief after SMT. Conclusion. Brain processing after SMT may lead to physiological relaxation via a decrease in sympathetic nerve activity. PMID:28167971

  11. Comparison of Early-Phase 11C-Deuterium-l-Deprenyl and 11C-Pittsburgh Compound B PET for Assessing Brain Perfusion in Alzheimer Disease.

    PubMed

    Rodriguez-Vieitez, Elena; Carter, Stephen F; Chiotis, Konstantinos; Saint-Aubert, Laure; Leuzy, Antoine; Schöll, Michael; Almkvist, Ove; Wall, Anders; Långström, Bengt; Nordberg, Agneta

    2016-07-01

    The PET tracer (11)C-deuterium-L-deprenyl ((11)C-DED) has been used to visualize activated astrocytes in vivo in patients with Alzheimer disease (AD). In this multitracer PET study, early-phase (11)C-DED and (11)C-Pittsburgh compound B ((11)C-PiB) (eDED and ePiB, respectively) were compared as surrogate markers of brain perfusion, and the extent to which (11)C-DED binding is influenced by brain perfusion was investigated. (11)C-DED, (11)C-PiB, and (18)F-FDG dynamic PET scans were obtained in age-matched groups comprising AD patients (n = 8), patients with mild cognitive impairment (n = 17), and healthy controls (n = 16). A modified reference Patlak model was used to quantify (11)C-DED binding. A simplified reference tissue model was applied to both (11)C-DED and (11)C-PiB to measure brain perfusion relative to the cerebellar gray matter (R1) and binding potentials. (11)C-PiB retention and (18)F-FDG uptake were also quantified as target-to-pons SUV ratios in 12 regions of interest (ROIs). The strongest within-subject correlations with the corresponding R1 values (R1,DED and R1,PiB, respectively) and with (18)F-FDG uptake were obtained when the eDED and ePiB PET data were measured 1-4 min after injection. The optimum eDED/ePiB intervals also showed strong, significant ROI-based intersubject Pearson correlations with R1,DED/R1,PiB and with (18)F-FDG uptake, whereas (11)C-DED binding was largely independent of brain perfusion, as measured by eDED. Corresponding voxelwise correlations confirmed the ROI-based results. Temporoparietal eDED or ePiB brain perfusion measurements were highly discriminative between patient and control groups, with discriminative ability statistically comparable to that of temporoparietal (18)F-FDG glucose metabolism. Hypometabolism extended over wider regions than hypoperfusion in patient groups compared with controls. The 1- to 4-min early-frame intervals of (11)C-DED or (11)C-PiB are suitable surrogate measures for brain perfusion. (11)C

  12. Brain MRI, Tc-99m HMPAO SPECT and F-18 FP-CIT PET/CT Findings in a Patient with Wilson Disease: A Case Report.

    PubMed

    Kim, Seungyoo; Song, In Uk; Chung, Yong An; Choi, Eun Kyung; Oh, Jin Kyoung

    2014-12-01

    A 34-year-old female had experienced head and hand tremors with a dystonic component for 8 months. Brain MRI showed T2 high signal intensity in the periaqueductal region, dorsal midbrain and dorsal upper pons. No abnormal uptake was noted on Tc-99m HMPAO SPECT or F-18 FP-CIT PET/CT. Wilson disease was diagnosed according to the 2008 consensus guideline from the American Association for the Study of Liver Disease and 2012 guideline from the European Association for the Study of the Liver. This case demonstrates T2 signal change in the basal ganglia, excluding the putamen, in a Wilson disease patient with relatively severe clinical findings, but normal Tc-99m HMPAO SPECT and F-18 FP-CIT PET/CT.

  13. Differentiation of Brain Tumor Recurrence from Post-Radiotherapy Necrosis with 11C-Methionine PET: Visual Assessment versus Quantitative Assessment.

    PubMed

    Minamimoto, Ryogo; Saginoya, Toshiyuki; Kondo, Chisato; Tomura, Noriaki; Ito, Kimiteru; Matsuo, Yuka; Matsunaga, Shigeo; Shuto, Takashi; Akabane, Atsuya; Miyata, Yoko; Sakai, Shuji; Kubota, Kazuo

    2015-01-01

    The aim of this multi-center study was to assess the diagnostic capability of visual assessment in L-methyl-11C-methionine positron emission tomography (MET-PET) for differentiating a recurrent brain tumor from radiation-induced necrosis after radiotherapy, and to compare it to the accuracy of quantitative analysis. A total of 73 brain lesions (glioma: 31, brain metastasis: 42) in 70 patients who underwent MET-PET were included in this study. Visual analysis was performed by comparison of MET uptake in the brain lesion with MET uptake in one of four regions (around the lesion, contralateral frontal lobe, contralateral area, and contralateral cerebellar cortex). The concordance rate and logistic regression analysis were used to evaluate the diagnostic ability of visual assessment. Receiver-operating characteristic curve analysis was used to compare visual assessment with quantitative assessment based on the lesion-to-normal (L/N) ratio of MET uptake. Interobserver and intraobserver κ-values were highest at 0.657 and 0.714, respectively, when assessing MET uptake in the lesion compared to that in the contralateral cerebellar cortex. Logistic regression analysis showed that assessing MET uptake in the contralateral cerebellar cortex with brain metastasis was significantly related to the final result. The highest area under the receiver-operating characteristic curve (AUC) with visual assessment for brain metastasis was 0.85, showing no statistically significant difference with L/Nmax of the contralateral brain (AUC = 0.89) or with L/Nmean of the contralateral cerebellar cortex (AUC = 0.89), which were the areas that were the highest in the quantitative assessment. For evaluation of gliomas, no specific candidate was confirmed among the four areas used in visual assessment, and no significant difference was seen between visual assessment and quantitative assessment. The visual assessment showed no significant difference from quantitative assessment of MET-PET with a

  14. Tariquidar-induced P-glycoprotein inhibition at the rat blood-brain barrier studied with (R)-11C-verapamil and PET.

    PubMed

    Bankstahl, Jens P; Kuntner, Claudia; Abrahim, Aiman; Karch, Rudolf; Stanek, Johann; Wanek, Thomas; Wadsak, Wolfgang; Kletter, Kurt; Müller, Markus; Löscher, Wolfgang; Langer, Oliver

    2008-08-01

    The multidrug efflux transporter P-glycoprotein (P-gp) is expressed in high concentrations at the blood-brain barrier (BBB) and is believed to be implicated in resistance to central nervous system drugs. We used small-animal PET and (R)-11C-verapamil together with tariquidar, a new-generation P-gp modulator, to study the functional activity of P-gp at the BBB of rats. To enable a comparison with human PET data, we performed kinetic modeling to estimate the rate constants of radiotracer transport across the rat BBB. A group of 7 Wistar Unilever rats underwent paired (R)-11C-verapamil PET scans at an interval of 3 h: 1 baseline scan and 1 scan after intravenous injection of tariquidar (15 mg/kg, n = 5) or vehicle (n = 2). After tariquidar administration, the distribution volume (DV) of (R)-11C-verapamil was 12-fold higher than baseline (3.68 +/- 0.81 vs. 0.30 +/- 0.08; P = 0.0007, paired t test), whereas the DVs were essentially the same when only vehicle was administered. The increase in DV could be attributed mainly to an increased influx rate constant (K1) of (R)-11C-verapamil into the brain, which was about 8-fold higher after tariquidar. A dose-response assessment with tariquidar provided an estimated half-maximum effect dose of 8.4 +/- 9.5 mg/kg. Our data demonstrate that (R)-11C-verapamil PET combined with tariquidar administration is a promising approach to measure P-gp function at the BBB.

  15. Intra-individual comparison of 18F-FET and 18F-DOPA in PET imaging of recurrent brain tumors

    PubMed Central

    Kratochwil, Clemens; Combs, Stephanie E.; Leotta, Karin; Afshar-Oromieh, Ali; Rieken, Stefan; Debus, Jürgen; Haberkorn, Uwe; Giesel, Frederik L.

    2014-01-01

    Background Both 18F-fluorodihydroxyphenylalanine (18F-DOPA) and 18F-fluoroethyltyrosine (18F-FET) have already been used successfully for imaging of brain tumors. The aim of this study was to evaluate differences between these 2 promising tracers to determine the consequences for imaging protocols and the interpretation of findings. Methods Forty minutes of dynamic PET imaging were performed on 2 consecutive days with both 18F-DOPA and 18F-FET in patients with recurrent low-grade astrocytoma (n = 8) or high-grade glioblastoma (n = 8). Time-activity-curves (TACs), standardized uptake values (SUVs) and compartment modeling of both tracers were analyzed, respectively. Results The TAC of DOPA-PET peaked at 8 minutes p.i. with SUV 5.23 in high-grade gliomas and 10 minutes p.i. with SUV 4.92 in low-grade gliomas. FET-PET peaked at 9 minutes p.i. with SUV 3.17 in high-grade gliomas and 40 minutes p.i. with SUV 3.24 in low-grade gliomas. Neglecting the specific uptake of DOPA into the striatum, the tumor-to-brain and tumor-to-blood ratios were higher for DOPA-PET. Kinetic modeling demonstrated a high flow constant k1 (mL/ccm/min), representing cellular internalization through AS-transporters, for DOPA in both high-grade (k1 = 0.59) and low-grade (k1 = 0.55) tumors, while lower absolute values and a relevant dependency from tumor-grading (high-grade k1 = 0.43; low-grade k1 = 0.33) were observed with FET. Conclusions DOPA-PET demonstrates superior contrast ratios for lesions outside the striatum, but SUVs do not correlate with grading. FET-PET can provide additional information on tumor grading and benefits from lower striatal uptake but presents lower contrast ratios and requires prolonged imaging if histology is not available in advance due to a more variable time-to-peak. PMID:24305717

  16. Perfusion-like template and standardized normalization-based brain image analysis using 18F-florbetapir (AV-45/Amyvid) PET.

    PubMed

    Hsiao, Ing-Tsung; Huang, Chin-Chang; Hsieh, Chia-Ju; Wey, Shiaw-Pyng; Kung, Mei-Ping; Yen, Tzu-Chen; Lin, Kun-Ju

    2013-06-01

    Amyloid positron emission tomography (PET) is an important noninvasive method for detecting amyloid burden in Alzheimer's disease (AD) patients. As amyloid PET images have limited anatomical information, magnetic resonance (MR) imaging is usually acquired to perform reliable spatial normalization needed for large-scale analysis. This work proposed and evaluated the performance of new MR-free spatial normalization methods using a perfusion-like template for amyloid PET imaging. Amyloid PET and MR images were collected in 35 subjects (cohort 1: 8 AD patients and 6 controls; cohort 2: 15 AD patients and 6 controls). Three ligand-related templates (AD, control, mixed group) and a perfusion-like template (pAV-45) from early time frames of amyloid PET images were constructed from cohort 1. The variations of (18)F-AV-45 standardized uptake value ratios (SUVRs) among AD patients, controls, and all subjects were tested with repeated two-way (template × brain region) analysis of variance (ANOVA) in cohort 2. (18)F-AV-45 SUVRs by region of interest analysis and voxelwise analysis between MR-based and MR-free approaches were compared and correlated to clinical and image parameters. Effect size (group mean SUVR difference between AD and control/standard deviation) was also evaluated for each template method. Significantly different (18)F-AV-45 SUVRs between MR-free spatial normalization and MR-based reference images were found among AD patients, controls, and all subjects by the effect of template and brain regions. The highest correlation (r=0.991) of (18)F-AV-45 SUVR to MR-based reference was found in the pAV-45 group. The SUVR percentage difference to MR-based reference showed the least variation and bias (control: -1.31±3.47 %; AD: -0.36±2.50 %) in the pAV-45 group as well. The voxelwise analysis showed the smallest t statistic value in pAV-45 followed by mixed, control, and AD groups when compared to MR-based reference images. Moreover, an overall larger effect size but

  17. Ivy sign, misery perfusion, and asymptomatic moyamoya disease: FLAIR imaging and (15)O-gas positron emission tomography.

    PubMed

    Vuignier, Sandra; Ito, Masaki; Kurisu, Kota; Kazumata, Ken; Nakayama, Naoki; Shichinohe, Hideo; Shiga, Tohru; Kiss, Jozsef Zoltan; Tamaki, Nagara; Houkin, Kiyohiro

    2013-11-01

    The prevalence of ivy sign on fluid-attenuated inversion recovery (FLAIR) imaging in patients with asymptomatic moyamoya disease is unclear. The aim of this study was to clarify the incidence of ivy sign in these patients, as well as the correlation between MRI and (15)O gas PET findings. A retrospective analysis including 16 consecutive patients with asymptomatic moyamoya disease enrolled between 2001 and 2010 in a single center. FLAIR imaging at the initial visit was categorized as ivy sign present, negative, or equivocal. Hemodynamic and metabolic parameters were quantified in 11 of 16 patients by (15)O-gas positron emission tomography, and the relationship between ivy sign and (15)O-gas PET parameters was analyzed. Cerebrovascular events within the follow-up period (54 ± 28 months) were also examined. Five of 16 asymptomatic moyamoya patients (31.3 %) had positive ivy sign (6/30 hemispheres, 20 %). In (15)O-gas PET examinations, 18 % of 22 hemispheres had elevated oxygen extraction fraction values that were significantly associated with positive ivy sign. Of these 16 asymptomatic moyamoya patients, six patients (37.5 %) underwent combined surgical revascularization. In this series, no patients experienced ischemic stroke, but one had intraventricular bleeding 1 year after surgery. Ivy sign on FLAIR imaging is still not rare in patients with moyamoya disease, even when asymptomatic. Although optimal management is still under debate, ivy sign may be an indicator of misery perfusion, and patients with asymptomatic moyamoya disease and ivy sign on FLAIR imaging will benefit from more careful follow-up.

  18. Gender Differences of Brain Glucose Metabolic Networks Revealed by FDG-PET: Evidence from a Large Cohort of 400 Young Adults

    PubMed Central

    Li, Kai; Zhu, Hong; Qi, Rongfeng; Zhang, Zhiqiang; Lu, Guangming

    2013-01-01

    Background Gender differences of the human brain are an important issue in neuroscience research. In recent years, an increasing amount of evidence has been gathered from noninvasive neuroimaging studies supporting a sexual dimorphism of the human brain. However, there is a lack of imaging studies on gender differences of brain metabolic networks based on a large population sample. Materials and Methods FDG PET data of 400 right-handed, healthy subjects, including 200 females (age: 25∼45 years, mean age±SD: 40.9±3.9 years) and 200 age-matched males were obtained and analyzed in the present study. We first investigated the regional differences of brain glucose metabolism between genders using a voxel-based two-sample t-test analysis. Subsequently, we investigated the gender differences of the metabolic networks. Sixteen metabolic covariance networks using seed-based correlation were analyzed. Seven regions showing significant regional metabolic differences between genders, and nine regions conventionally used in the resting-state network studies were selected as regions-of-interest. Permutation tests were used for comparing within- and between-network connectivity between genders. Results Compared with the males, females showed higher metabolism in the posterior part and lower metabolism in the anterior part of the brain. Moreover, there were widely distributed patterns of the metabolic networks in the human brain. In addition, significant gender differences within and between brain glucose metabolic networks were revealed in the present study. Conclusion This study provides solid data that reveal gender differences in regional brain glucose metabolism and brain glucose metabolic networks. These observations might contribute to the better understanding of the gender differences in human brain functions, and suggest that gender should be included as a covariate when designing experiments and explaining results of brain glucose metabolic networks in the control

  19. Gender differences of brain glucose metabolic networks revealed by FDG-PET: evidence from a large cohort of 400 young adults.

    PubMed

    Hu, Yuxiao; Xu, Qiang; Li, Kai; Zhu, Hong; Qi, Rongfeng; Zhang, Zhiqiang; Lu, Guangming

    2013-01-01

    Gender differences of the human brain are an important issue in neuroscience research. In recent years, an increasing amount of evidence has been gathered from noninvasive neuroimaging studies supporting a sexual dimorphism of the human brain. However, there is a lack of imaging studies on gender differences of brain metabolic networks based on a large population sample. FDG PET data of 400 right-handed, healthy subjects, including 200 females (age: 25:45 years, mean age ± SD: 40.9 ± 3.9 years) and 200 age-matched males were obtained and analyzed in the present study. We first investigated the regional differences of brain glucose metabolism between genders using a voxel-based two-sample t-test analysis. Subsequently, we investigated the gender differences of the metabolic networks. Sixteen metabolic covariance networks using seed-based correlation were analyzed. Seven regions showing significant regional metabolic differences between genders, and nine regions conventionally used in the resting-state network studies were selected as regions-of-interest. Permutation tests were used for comparing within- and between-network connectivity between genders. Compared with the males, females showed higher metabolism in the posterior part and lower metabolism in the anterior part of the brain. Moreover, there were widely distributed patterns of the metabolic networks in the human brain. In addition, significant gender differences within and between brain glucose metabolic networks were revealed in the present study. This study provides solid data that reveal gender differences in regional brain glucose metabolism and brain glucose metabolic networks. These observations might contribute to the better understanding of the gender differences in human brain functions, and suggest that gender should be included as a covariate when designing experiments and explaining results of brain glucose metabolic networks in the control and experimental individuals or patients.

  20. Approaching complete inhibition of P-glycoprotein at the human blood-brain barrier: an (R)-[11C]verapamil PET study.

    PubMed

    Bauer, Martin; Karch, Rudolf; Zeitlinger, Markus; Philippe, Cécile; Römermann, Kerstin; Stanek, Johann; Maier-Salamon, Alexandra; Wadsak, Wolfgang; Jäger, Walter; Hacker, Marcus; Müller, Markus; Langer, Oliver

    2015-05-01

    As P-glycoprotein (Pgp) inhibition at the blood-brain barrier (BBB) after administration of a single dose of tariquidar is transient, we performed positron emission tomography (PET) scans with the Pgp substrate (R)-[(11)C]verapamil in five healthy volunteers during continuous intravenous tariquidar infusion. Total distribution volume (VT) of (R)-[(11)C]verapamil in whole-brain gray matter increased by 273 ± 78% relative to baseline scans without tariquidar, which was higher than previously reported VT increases. During tariquidar infusion whole-brain VT was comparable to VT in the pituitary gland, a region not protected by the BBB, which suggested that we were approaching complete Pgp inhibition at the human BBB.

  1. Reduced grey matter metabolism due to white matter edema allows optimal assessment of brain tumors on 18F-FDG-PET.

    PubMed

    Pourdehnad, Michael; Basu, Sandip; Duarte, Paulo; Okpaku, Aubrey S; Saboury, Babak; Hustinx, Roland; Alavi, Abass

    2011-01-01

    The main aim of this research was to demonstrate that the cortical and subcortical grey matter hypometabolism as revealed by fluorine-18 fluorodesoxyglucose-positron emission tomography ((18)F-FDG-PET) imaging in brain tumors is related to associated edema as demonstrated by magnetic resonance imaging (MRI). This in turn enhances the ability to assess disease activity in the tumor and the degree of loss of cerebral function in the adjacent and distant structures. We evaluated brain T1 and T2 weighted MRI and (18)F-FDG-PET scans of 29 patients (19 adult, 10 pediatric) with history of brain tumor. Tumor histology types included 21 gliomas, 1 melanoma, 1 primitive neuroectodermal tumor, 3 medulloblastomas and 3 ependymomas. The majority of scans were performed within the same week (94% <1 month. The extent of hypo and hypermetabolism was assessed on the (18)F-FDG-PET scans. A template of 12 regions of interest (ROI) was applied and the laterality indices of the regional counts (signal intensity) were computed. Extent of edema, enhancement, and anatomical change were assessed on the MRI scans. Extent of edema in the same ROI was evaluated by a 6-point semiquantitative scale and laterality indices were generated. Metabolic activity of the grey matter was correlated with the extent of edema using these indices. In all cases where edema was present, significant hypometabolism was observed in the adjacent structures. Overall, there was a strong correlation between the extent of edema and severity of hypometabolism (r=0.92, P=0.01). This was true regardless of the location of edema, whether there was history of radiation treatment (r=0.91, P=0.03), or not (r=0.97, P=0.17). In conclusion, edema independent of underlying variables appeared to contribute significantly to cortical and sub-cortical grey matter hypometabolism observed in patients with brain tumors. This would indicate that brain tumors can be successfully assessed by (18)F-FDG-PET and therefore the efforts for

  2. Clinical Value of [{sup 11}C]Methionine PET for Stereotactic Radiation Therapy With Intensity Modulated Radiation Therapy to Metastatic Brain Tumors

    SciTech Connect

    Miwa, Kazuhiro; Matsuo, Masayuki; Shinoda, Jun; Aki, Tatsuki; Yonezawa, Shingo; Ito, Takeshi; Asano, Yoshitaka; Yamada, Mikito; Yokoyama, Kazutoshi; Yamada, Jitsuhiro; Yano, Hirohito; Iwama, Toru

    2012-12-01

    Purpose: This study investigated the clinical impact of {sup 11}C-labeled methionine-positron emission tomography (MET-PET) for stereotactic radiation therapy with intensity modulated radiation therapy (SRT-IMRT) in metastatic brain tumors. Methods and Materials: Forty-two metastatic brain tumors were examined. All tumors were treated with SRT-IMRT using a helical tomotherapy system. Gross tumor volume (GTV) was defined and drawn on the stereotactic magnetic resonance (MR) image, taking into account the respective contributions of MR imaging and MET-PET. Planning target volume (PTV) encompassed the GTV-PET plus a 2-mm margin. SRT-IMRT was performed, keeping the dose for PTV at 25-35 Gy in 5 fractions. The ratio of the mean value of MET uptake to the contralateral normal brain (L/N ratio) was plotted for the PTV prior to SRT-IMRT, at 3 months following SRT-IMRT, and at 6 months following SRT-IMRT. Tumor characteristic changes of MET uptake before and after SRT-IMRT were evaluated quantitatively, comparing them with MRI examination. Results: Mean {+-} SD L/N ratios were 1.95 {+-} 0.83, 1.18 {+-} 0.21, and 1.12 {+-} 0.25 in the pre-SRT-IMRT group, in the 3 months post-SRT-IMRT group, and in the 6 months post-SRT-IMRT group, respectively. Differences in the mean L/N ratio between the pre-SRT-IMRT group and the 3-month post-SRT-IMRT group and between the pre-SRT-IMRT group and the 6 month post-SRT-IMRT group were statistically significant, irrespective of MRI examination. Conclusions: We showed examples of metastatic lesions demonstrating significant decreases in MET uptake following SRT-IMRT. MET-PET seems to have a potential role in providing additional information, although MRI remains the gold standard for diagnosis and follow-up after SRT-IMRT. The present study is a preliminary approach, but to more clearly define the impact of PET-based radiosurgical assessment, further experimental and clinical analyses are required.

  3. Brain translocator protein occupancy by ONO-2952 in healthy adults: A Phase 1 PET study using [(11) C]PBR28.