Joint Assessment of Quantitative 18F-Florbetapir and 18F-FDG Regional Uptake Using Baseline Data from the ADNI

International audienceJoint analysis of amyloid and metabolic PET patterns across healthy, mild cognitive impairment (MCI), and Alzheimer's disease (AD) subjects was performed using baseline 18F-florbetapir and 18F-FDG PET of 684 subjects from the ADNI (251 normal, 204 stable MCI, 85 AD converters, and 144 AD). Correlation between regional amyloid and metabolic uptake was measured and predictive value of PET profile regarding AD conversion in cognitively impaired subjects was assessed using survival analysis and support vector machine classification (SVM). The highest correlations were found in the temporal cortex, precuneus, and posterior cingulum. With respect to normal controls, amyloid load increase was diffuse and early in MCI subjects, whereas metabolism decrease occurred later and predominated in temporo-parietal, precuneus, and cingulate cortices. Five-year AD conversion rates in cognitively impaired subjects were 5%, 22%, 42%, and 78% in amyloid-/FDG-, amyloid-/FDG+, amyloid+/FDG-, and amyloid+/FDG+ subjects respectively (mean follow-up 37±14 months). Using SVM, the combination of ADAS-cog score, amyloid PET, and FDG PET yielded better performance in predicting AD conversion (77% accuracy; 58% positive predictive value; 88% negative predictive value) than ADAS-cog (72%; 52%; 86%), amyloid PET (72%; 52%; 87%), and FDG PET (67%; 47%; 84%). This study attests the complementary value of amyloid and FDG PET in MCI assessment and the efficiency of combined cognitive, amyloid, and metabolic scores to predict AD conversion

Comparison of CSF markers and semi-quantitative amyloid PET in Alzheimer's disease diagnosis and in cognitive impairment prognosis using the ADNI-2 database

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Comparative assessment of linear least-squares, nonlinear least-squares, and Patlak graphical method for regional and local quantitative tracer kinetic modelling in cerebral dynamic 18 F-FDG PET

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Actualités en cardiologie isotopique : applications des nouvelles caméras CZT

International audienceWe offer a brief overview of recent advances in the instrumentation of dedicated cardiac gamma cameras. We focus on the expected benefits in the fields of classical myocardial perfusion imaging and gated blood-pool SPECT. We also report some preliminary results regarding two active research topics at Montpellier University Hospital: quantification of myocardial perfusion reserve using dynamic SPECT, and detection of trigger zones after myocardial infraction using a 201 Tl/ 123 I-MIBG dual isotope protocolNous proposons ici une synthèse succincte des avancées récentes en termes d'instrumentation des gamma-caméras orientées cardiologie. Y sont détaillées, en particulier, les possibilités offertes en imagerie de perfusion myocardique classique et en tomographie cavitaire. Y sont, par ailleurs, rapportés les résultats préliminaires relatifs à deux thématiques de recherche actives au CHU de Montpellier portant sur la quantification de réserve de perfusion myocardique par SPECT dynamique et sur la détection de zones gâchettes en post-SCA précoce par protocole double isotope 201 Tl/ 123 I-MIBG

Diagnostic and prognostic value of amyloid PET textural and shape features: comparison with classical semi-quantitative rating in 760 patients from the ADNI-2 database

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Development and clinical validation of a hybrid method for semiautomated left ventricle endocardial and epicardial boundary extraction on cine-magnetic resonance images

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Statistic-algebraic Tuning Optimization for Regularized Iterative Reconstruction (PML and EMS) in Emission Tomography

International audienceMost of the regularized iterative reconstruction schemes employed in emission tomography (such as penalized maximum-likelihood, PML) usually require the adjustment of a scalar parameter that determines the strength of the a-priori information regarding the studied object. Empirical selection of remains hazardous since its optimal value depends on the morphological structure of the reconstructed image and the data signal to noise ratio (SNR), which explains partly the scarce utilization of penalized reconstruction in clinical routine. In this paper, we derive a simple optimization criterion for that relies on a statistical description of the noise propagation when iteratively updating the image estimate and on a surrogate algebraic formulation holding for both PML and expectation-maximization-smooth (EMS) iterative reconstruction. When incorporated into each iteration step, the statistic-algebraic tuning optimization (SATO) yields two new optimized regularized iterative methods: SATO-PML and SATO-EMS. These methods are compared with classical MLEM reconstruction followed by optimal Gaussian post-filtering (ML-opt) through Monte-Carlo experiments involving the Hoffman brain phantom and the Shepp-Logan phantom. It is shown that, whatever the studied object and the count rate, SATO-PML and SATO-EMS are convergent in terms of and produce images with bias, variance and contrast properties that are at least as good as those of the ML-opt images. The two proposed algorithms are also evaluated using realistic PET data from a Hoffman phantom produced using the GATE platform in order to demonstrate the feasibility of our SATO scheme with actual data

Brain 18F-FDG PET analysis via interval-valued reconstruction: proof of concept for Alzheimer’s disease diagnosis

International audienceObjective: We propose an innovative approach for 18F-FDG PET analysis based on an interval-valued reconstruction of 18F-FDG brain distribution. Its diagnostic performance for Alzheimer's disease (AD) diagnosis with comparison to a validated post-processing software was assessed.Methods: Brain 18F-FDG PET data from 26 subjects were acquired in a clinical routine setting. Raw data were reconstructed using an interval-valued version of the ML-EM algorithm called NIBEM that stands for Non-Additive interval-based expectation maximization. Subject classification was obtained via interval-based statistical comparison (intersection ratio, IR) between cortical regions of interest (ROI) including parietal, temporal, and temporo-mesial cortices and a reference region, the sub-cortical grey nuclei, known not to be affected by AD. In parallel, PET images were post-processed using a validated automated software based on the computation of ROI normalized uptake ratios standard deviation (SUVr SD) with reference to a healthy control database (Siemens Scenium). Clinical diagnosis made during follow-up was considered as the gold-standard for patient classification (16 healthy controls and 10 AD patients).Results: Both methods provided cortical ROI indices that were significantly different between controls and AD patients. The area under the ROC curve for control/AD classification was statistically identical (0.96 for NIBEM IR and 0.95 for Scenium SUVr SD). At the optimal threshold, the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were, respectively, 100%, 88%, 92%, 83%, and 100% for both Scenium SUVr SD and NIBEM IR methods.Conclusion: This preliminary study shows that interval-valued reconstruction allows self-consistent analysis of brain 18F-FDG PET data, yielding diagnostic performances that seem promising with respect to those of a commercial post-processing software based on SUVr SD analysis

Pineal Anaplastic Ependymoma With Multifocal Intradural Extramedullary Metastases on MRI and 18FDG-PET

International audienceA 49-year-old woman presented to the emergency room with subacute paraparesis associated with bilateral cervicobrachial neuralgia. Brain and spine MRI revealed a heterogeneous hypervascular pineal tumor and a multifocal thoracolumbar intradural-extramedullary infiltrate with signs of medullary compression. C7-T2 laminectomy was performed on the same day for medullary decompression, allowing for partial lesion excision. Histological examination was in favor of a poorly differentiated anaplastic ependymoma. Two weeks later, FDG-PET showed markedly increased uptake in the pineal mass and significant hypermetabolism of the spinal metastases

Therapeutic Response to Rituximab in IgG4-Related Hypophysitis Evidenced on 18F-FDG PET and MRI.

International audienceBaseline F-FDG PET and MRI were performed in a patient with IgG4-related hypophysitis, showing a 15-mm hypervascular hypermetabolic lesion with sellar and suprasellar extension. Lack of response after 10 months of first-line corticosteroid therapy was demonstrated on both F-FDG PET and MRI. Three months later, after 2 injections of 1 g of rituximab associated with continued corticosteroid therapy, MRI showed substantial shrinkage of the pituitary lesion with minimal residual Gd enhancement, whereas F-FDG PET evidenced complete metabolic response. As such, joint F-FDG PET and MRI assessment during therapy may have a potential interest for treatment response evaluation in pituitary IgG4-related disease