2021
Free‐breathing 3D cardiac T1 mapping with transmit B1 correction at 3T
Han P, Marin T, Djebra Y, Landes V, Zhuo Y, Fakhri G, Ma C. Free‐breathing 3D cardiac T1 mapping with transmit B1 correction at 3T. Magnetic Resonance In Medicine 2021, 87: 1832-1845. PMID: 34812547, PMCID: PMC8810588, DOI: 10.1002/mrm.29097.Peer-Reviewed Original ResearchMeSH KeywordsHeartHumansImage Interpretation, Computer-AssistedMagnetic Resonance ImagingPhantoms, ImagingReproducibility of ResultsConceptsFlip-angle estimationCardiac T<sub>1</sub> mappingGradient echo readoutThrough-plane spatial resolutionImaging timePractical imaging timesFree breathingPhantom studyB1 correctionAccelerated imagingIn-planeT)-spaceMyocardial T<sub>1</sub> valuesSubspace-based methodsSpatial resolutionImaging experimentsAcquisition schemeT)-space dataSubject-specific timeCorrectionModified Look-Locker inversion recoveryLook-Locker inversion recoveryTime of data acquisitionAverage imaging timeInversion-recovery sequenceA layered single-side readout depth of interaction time-of-flight-PET detector
Bläckberg L, Sajedi S, Fakhri G, Sabet H. A layered single-side readout depth of interaction time-of-flight-PET detector. Physics In Medicine And Biology 2021, 66: 045025. PMID: 33570050, PMCID: PMC8130834, DOI: 10.1088/1361-6560/abd592.Peer-Reviewed Original ResearchMeSH KeywordsAlgorithmsBiophysical PhenomenaEquipment DesignImage Interpretation, Computer-AssistedPhotometryPhotonsPositron-Emission TomographyScintillation CountingTime FactorsConceptsDepth of interactionMulti-pixel photon counterDepth-of-interaction determinationDepth-of-interaction informationTime resolutionTime resolution valuesReduced crystal thicknessNon-DOI detectorsOptical photonsScintillator arrayPET detectorsPhoton counterCrystal pixelsReadout schemeCrystal arrayCrystal thicknessTransport simulationsDetectorPhotodetector arrayReadoutPixel sizePhotodetectorsResolution valuesFirst layerSignal amplitude
2015
Matched signal detection on graphs: Theory and application to brain imaging data classification
Hu C, Sepulcre J, Johnson K, Fakhri G, Lu Y, Li Q. Matched signal detection on graphs: Theory and application to brain imaging data classification. NeuroImage 2015, 125: 587-600. PMID: 26481679, DOI: 10.1016/j.neuroimage.2015.10.026.Peer-Reviewed Original ResearchMeSH KeywordsAlgorithmsAlzheimer DiseaseBrainBrain MappingHumansImage Interpretation, Computer-AssistedMachine LearningMagnetic Resonance ImagingModels, NeurologicalModels, TheoreticalPositron-Emission TomographyConceptsImage data classificationWeighted energy detectorGraph-signalGraph Laplacian eigenvaluesEnergy detectorManifold structureProblem of Alzheimer's diseaseData classificationGraph LaplacianSubspace detectorWeighted graphMSD approachSignal processingSignal detectionIntrinsic structureLaplacian eigenvaluesSubspaceTest statisticsGraphRandom signalsData setsLowest eigenvalueGaussian distributionTraditional methodsEigenvalues
2014
4D numerical observer for lesion detection in respiratory‐gated PET
Lorsakul A, Li Q, Trott C, Hoog C, Petibon Y, Ouyang J, Laine A, Fakhri G. 4D numerical observer for lesion detection in respiratory‐gated PET. Medical Physics 2014, 41: 102504. PMID: 25281979, PMCID: PMC4281099, DOI: 10.1118/1.4895975.Peer-Reviewed Original ResearchMeSH KeywordsAlgorithmsComputer SimulationFluorodeoxyglucose F18HumansImage Interpretation, Computer-AssistedLung DiseasesModels, BiologicalMonte Carlo MethodMotionPhantoms, ImagingPositron-Emission TomographyRadiopharmaceuticalsRegression AnalysisRespiratory-Gated Imaging TechniquesSignal-To-Noise RatioConceptsRespiratory-gated positron emission tomographyMotion-corrected imagesDetection signal-to-noise ratioLesion detection taskNumerical observationsLesion detection performanceSignal-to-noise ratioPositron emission tomography sinogramsSpherical lesionsHotelling observerMotion correction methodPositron emission tomographyGeant4 ApplicationTomographic EmissionChannelized Hotelling observerAnthropomorphic phantomScanner geometryOSEM algorithmMonte Carlo simulationsPET framesImprove lesion detectionLesion detectionSignal-to-noise ratio measurementsActivity distributionConventional 3D approachEffect of time‐of‐flight and point spread function modeling on detectability of myocardial defects in PET
Schaefferkoetter J, Ouyang J, Rakvongthai Y, Nappi C, El Fakhri G. Effect of time‐of‐flight and point spread function modeling on detectability of myocardial defects in PET. Medical Physics 2014, 41: 062502. PMID: 24877836, PMCID: PMC4032408, DOI: 10.1118/1.4875725.Peer-Reviewed Original ResearchMeSH KeywordsCardiomyopathiesComputer SimulationFluorodeoxyglucose F18HeartHumansImage Interpretation, Computer-AssistedModels, TheoreticalPoisson DistributionPositron-Emission TomographyConceptsSignal-to-noise ratioDetection signal-to-noise ratioPoint spread functionObserver signal-to-noise ratioEffects of time-of-flightMyocardial defectsHuman observer performanceDefect detectionSlow convergenceTime-of-flight (TOFNon-PSFPostreconstruction smoothingFDG-PET dataTime-of-flightPSF reconstructionCombination of TOFNon-TOFIterationObserver performanceClinical practiceSpread functionReconstruction parametersReconstruction protocolsIterative methodDetectionPattern recognition for rapid T2 mapping with stimulated echo compensation
Huang C, Altbach M, Fakhri G. Pattern recognition for rapid T2 mapping with stimulated echo compensation. Magnetic Resonance Imaging 2014, 32: 969-974. PMID: 24853466, PMCID: PMC4099291, DOI: 10.1016/j.mri.2014.04.014.Peer-Reviewed Original ResearchMeSH KeywordsAlgorithmsArtifactsArtificial IntelligenceBrainHumansImage EnhancementImage Interpretation, Computer-AssistedMagnetic Resonance ImagingPattern Recognition, AutomatedPilot ProjectsReproducibility of ResultsSensitivity and SpecificityTowards coronary plaque imaging using simultaneous PET-MR: a simulation study
Petibon Y, Fakhri G, Nezafat R, Johnson N, Brady T, Ouyang J. Towards coronary plaque imaging using simultaneous PET-MR: a simulation study. Physics In Medicine And Biology 2014, 59: 1203-1222. PMID: 24556608, PMCID: PMC4061607, DOI: 10.1088/0031-9155/59/5/1203.Peer-Reviewed Original ResearchMeSH KeywordsComputer SimulationCoronary AngiographyCoronary StenosisHumansImage Interpretation, Computer-AssistedImaging, Three-DimensionalMagnetic Resonance AngiographyModels, CardiovascularMultimodal ImagingPhantoms, ImagingPositron-Emission TomographyReproducibility of ResultsSensitivity and SpecificityConceptsSimultaneous PET-MRChannelized Hotelling observerAttenuation mapMotion correctionPET-MRFluorodeoxyglucose-positron emission tomography imagingRespiratory motion fieldsMotion correction methodCho SNRMotion correction techniqueAnthropomorphic phantomUncorrected reconstructionsRespiratory motionXCAT phantomCoronary plaque imagingMonte Carlo simulationsPET reconstructionXCATActivity distributionCardiac gatingNon-rigid registrationHotelling observerCarlo simulationsPlaque imagingPhantomEvaluating Structural Symmetry of Weighted Brain Networks via Graph Matching
Hu C, El Fakhri G, Li Q. Evaluating Structural Symmetry of Weighted Brain Networks via Graph Matching. Lecture Notes In Computer Science 2014, 17: 733-740. PMID: 25485445, DOI: 10.1007/978-3-319-10470-6_91.Peer-Reviewed Original ResearchConceptsAttention deficit hyperactivity disorderNetwork symmetryBrain networksType of Attention Deficit Hyperactivity DisorderWeighted brain networksConsistent with former findingsDeficit hyperactivity disorderRs-fMRI networksResting state fMRISymmetry levelInattentive typeHyperactivity disorderBrain areasSymmetryStructural symmetryBrain connectivityFunctional networksResting stateLarger thresholdsBrainFMRIHigher levelsGraph matchingNode pairsNormal subjects
2013
Matched Signal Detection on Graphs: Theory and Application to Brain Network Classification
Hu C, Cheng L, Sepulcre J, El Fakhri G, Lu Y, Li Q. Matched Signal Detection on Graphs: Theory and Application to Brain Network Classification. Lecture Notes In Computer Science 2013, 23: 1-12. PMID: 24683953, DOI: 10.1007/978-3-642-38868-2_1.Peer-Reviewed Original ResearchMeSH KeywordsAlgorithmsAlzheimer DiseaseAniline CompoundsBenzothiazolesBrainBrain MappingConnectomeHumansImage EnhancementImage Interpretation, Computer-AssistedNerve NetNeural PathwaysPattern Recognition, AutomatedPositron-Emission TomographyReproducibility of ResultsSensitivity and SpecificityThiazolesTissue DistributionConceptsBrain network classificationNetwork classification problemWeighted energy detectorPrinciple component analysisSub-manifold structureTraditional principle component analysisSubspace detectionTraining dataEnergy detectorGraph structureProblem of Alzheimer's diseaseGraph LaplacianNetwork classificationNoise varianceLevel of smoothnessWeighted graphSignal detectionIntrinsic structureSignal modelGraphSubspaceIsing modelNoiseSignal variationsComponent analysis
2011
Improvement in Lesion Detection with Whole-Body Oncologic Time-of-Flight PET
Fakhri G, Surti S, Trott C, Scheuermann J, Karp J. Improvement in Lesion Detection with Whole-Body Oncologic Time-of-Flight PET. Journal Of Nuclear Medicine 2011, 52: 347-353. PMID: 21321265, PMCID: PMC3088884, DOI: 10.2967/jnumed.110.080382.Peer-Reviewed Original ResearchConceptsTime-of-flight PETTime-of-flightTOF-PETTime-of-flight reconstructionBody mass indexList-mode dataNon-TOF PETObserver signal-to-noise ratioOrdered-subset expectation maximizationMass indexNon-TOFLesion detectionLesion detection performanceSpherical lesionsFunction of body mass indexSignal-to-noise ratioScan timePatient studiesLesion visibilityArtificial lesionsLiver lesionsPatientsLesionsLesion locationLow lesions
2010
MRI-Assisted PET Motion Correction for Neurologic Studies in an Integrated MR-PET Scanner
Catana C, Benner T, van der Kouwe A, Byars L, Hamm M, Chonde D, Michel C, Fakhri G, Schmand M, Sorensen A. MRI-Assisted PET Motion Correction for Neurologic Studies in an Integrated MR-PET Scanner. Journal Of Nuclear Medicine 2010, 52: 154-161. PMID: 21189415, PMCID: PMC3125596, DOI: 10.2967/jnumed.110.079343.Peer-Reviewed Original ResearchMeSH KeywordsAlgorithmsBrainHumansImage Interpretation, Computer-AssistedMagnetic Resonance ImagingMotionPhantoms, ImagingPositron-Emission TomographyConceptsLines of responseMotion correctionPET motion correctionRigid-body motion correctionMC algorithmPET volumesQuantitative accuracyMR-PET scannersPET image qualityScatter sinogramEcho-planar imagingHoffman phantomSinogram spaceList-modeRandom coincidencesMotion tracking techniquePrototype scannerPhantom volumeImage qualityMR-PETMC methodPET dataSinogramPhantomVolunteer studiesNovel Scatter Compensation of List-Mode PET Data Using Spatial and Energy Dependent Corrections
Guérin B, Fakhri G. Novel Scatter Compensation of List-Mode PET Data Using Spatial and Energy Dependent Corrections. IEEE Transactions On Medical Imaging 2010, 30: 759-773. PMID: 21118770, PMCID: PMC3120772, DOI: 10.1109/tmi.2010.2095025.Peer-Reviewed Original ResearchMeSH KeywordsAlgorithmsArtifactsImage EnhancementImage Interpretation, Computer-AssistedPattern Recognition, AutomatedPhantoms, ImagingPositron-Emission TomographyReproducibility of ResultsSensitivity and SpecificityConceptsScattered coincidencesEnergy resolutionE-pdfNCAT phantomDependent correctionsEnergy of individual photonsScatter correctionEnergy dependent correctionsEnergy probability density functionScatter correction schemeTotal energy spectrumList-mode acquisitionEnergy informationPositron emission tomography dataActivity distribution estimationScatter sinogramIndividual photonsEnergy spectrumCylindrical phantomEnergy distributionMonte Carlo simulationsScattering approachPhotonsScatteringScattering component
2009
Monte Carlo modeling of cascade gamma rays in 86Y PET imaging: preliminary results
Zhu X, Fakhri G. Monte Carlo modeling of cascade gamma rays in 86Y PET imaging: preliminary results. Physics In Medicine And Biology 2009, 54: 4181-4193. PMID: 19521011, PMCID: PMC3111055, DOI: 10.1088/0031-9155/54/13/014.Peer-Reviewed Original ResearchConceptsCascade gamma raysScatter fractionGamma raysPhoton energy distributionLow count ratesHigh-energy photonsMonte Carlo programScatter correction methodGATE simulation packageMonte Carlo modelDevelopment of correction methodsSpatial resolutionGamma photonsEnergy windowCount rateScattering eventsRandom coincidencesEnergy distributionPhantom acquisitionsPersonal dosimetryPET imagingVariance reduction techniquesPhotonsCorrection methodSimSET
2007
Pre-operative estimation of esophageal tumor metabolic length in FDG-PET images with surgical pathology confirmation
Mamede M, Fakhri G, Abreu-e-Lima P, Gandler W, Nosé V, Gerbaudo V. Pre-operative estimation of esophageal tumor metabolic length in FDG-PET images with surgical pathology confirmation. Annals Of Nuclear Medicine 2007, 21: 553-562. PMID: 18092131, DOI: 10.1007/s12149-007-0040-0.Peer-Reviewed Original ResearchConceptsEndoscopic ultrasoundFDG-PETSurgical pathologyFDG-PET computed tomographyMaximum standardized uptake valueFluorodeoxyglucose positron emission tomographyUntreated esophageal carcinomaStandardized uptake valueMethodsThirty-four patientsPositive nonsignificant correlationFDG-PET imagingPre-operative estimationPositron emission tomographyAverage SUVNeoadjuvant therapyTumor involvementTumor lengthEsophageal carcinomaNoninvasive delineationEsophageal cancerUptake valueInferior extentObjectiveThe aimMethodsThirty-fourEmission tomography
2006
Generalized five‐dimensional dynamic and spectral factor analysis
Fakhri G, Sitek A, Zimmerman R, Ouyang J. Generalized five‐dimensional dynamic and spectral factor analysis. Medical Physics 2006, 33: 1016-1024. PMID: 16696478, DOI: 10.1118/1.2179168.Peer-Reviewed Original Research
2005
Collimator Optimization for Detection and Quantitation Tasks: Application to Gallium-67 Imaging
Moore S, Kijewski M, Fakhri G. Collimator Optimization for Detection and Quantitation Tasks: Application to Gallium-67 Imaging. IEEE Transactions On Medical Imaging 2005, 24: 1347-1356. PMID: 16229420, DOI: 10.1109/tmi.2005.857211.Peer-Reviewed Original ResearchMeSH KeywordsCitratesComputer SimulationComputer-Aided DesignEquipment DesignEquipment Failure AnalysisGalliumHumansImage EnhancementImage Interpretation, Computer-AssistedModels, BiologicalNeoplasmsPhantoms, ImagingPositron-Emission TomographyRadiopharmaceuticalsReproducibility of ResultsSensitivity and SpecificityConceptsMedium-energy low-penetration collimatorCollimator optimizationGeometric spatial resolutionPhotopeak energy windowSimulation of photon transportLead X-raysClinical imaging tasksActivity estimation taskSignal-to-noise ratioGallium-67 imagingContaminating photonsEnergy windowGeometric efficiencyCollimator designFixed energyPhoton transportOptimal collimatorCollimatorHotelling observerFWHMSpatial resolutionNuclear medicineDetectorResolution valuesImaging tasksQuantitative dynamic cardiac 82Rb PET using generalized factor and compartment analyses.
El Fakhri G, Sitek A, Guérin B, Kijewski M, Di Carli M, Moore S. Quantitative dynamic cardiac 82Rb PET using generalized factor and compartment analyses. Journal Of Nuclear Medicine 2005, 46: 1264-71. PMID: 16085581.Peer-Reviewed Original ResearchMeSH KeywordsAdultAgedAged, 80 and overAlgorithmsComputer SimulationCoronary Artery DiseaseFeasibility StudiesFemaleHeartHumansImage Interpretation, Computer-AssistedMaleMiddle AgedModels, CardiovascularPositron-Emission TomographyRadiopharmaceuticalsReproducibility of ResultsRubidium RadioisotopesSensitivity and SpecificitySeverity of Illness IndexConceptsMyocardial perfusionAbsolute myocardial perfusionCatheterization resultsMyocardial tissue extractsDipyridamole stressCardiac PETClinical valueMyocardial factorsFactor analysis of dynamic sequencesPatient studiesLVNoninvasive estimationAccurate input functionPatientsCompartment analysisAverage errorPerfusionParametric mappingTissue extractsRV contributionRV