2024
Accelerated 3D metabolite T1 mapping of the brain using variable‐flip‐angle SPICE
Zhao Y, Li Y, Guo R, Jin W, Sutton B, Ma C, Fakhri G, Li Y, Luo J, Liang Z. Accelerated 3D metabolite T1 mapping of the brain using variable‐flip‐angle SPICE. Magnetic Resonance In Medicine 2024, 92: 1310-1322. PMID: 38923032, DOI: 10.1002/mrm.30200.Peer-Reviewed Original ResearchConceptsLow-rank tensor modelGeneralized series modelMetabolite TExperimental resultsBrain metabolitesClinically acceptable scan timeEfficient encodingPhantom experimental resultsAcceptable scan timeNoisy dataSparse samplingImaging problemsData processingHealthy subject dataVariable flip angleFlip angleTensor modelSaturation effectsQuantitative metabolic imagingMRSI techniquePhantomScan timeData acquisitionMetabolic imagingT1 mapping
2023
Attentive continuous generative self-training for unsupervised domain adaptive medical image translation
Liu X, Prince J, Xing F, Zhuo J, Reese T, Stone M, El Fakhri G, Woo J. Attentive continuous generative self-training for unsupervised domain adaptive medical image translation. Medical Image Analysis 2023, 88: 102851. PMID: 37329854, PMCID: PMC10527936, DOI: 10.1016/j.media.2023.102851.Peer-Reviewed Original ResearchMeSH KeywordsAnisotropyBayes TheoremHumansImage Processing, Computer-AssistedLearningReproducibility of ResultsUncertaintyConceptsUnsupervised domain adaptationImage translationProblem of domain shiftSelf-trainingImage modality translationLabeled source domainTarget domain dataSelf-attention schemeAlternating optimization schemeHeterogeneous target domainContinuous value predictionPseudo-labelsDomain adaptationUDA methodsDomain shiftSoftmax probabilitiesSource domainTarget domainVariational BayesBackground regionsTranslation tasksTraining processDomain dataGeneration taskOptimization schemeNoise-Robust Sleep Staging via Adversarial Training With an Auxiliary Model
Yoo C, Liu X, Xing F, Fakhri G, Woo J, Kang J. Noise-Robust Sleep Staging via Adversarial Training With an Auxiliary Model. IEEE Transactions On Biomedical Engineering 2023, 70: 1252-1263. PMID: 36227815, DOI: 10.1109/tbme.2022.3214269.Peer-Reviewed Original ResearchConceptsProblem of domain shiftTarget networkConsumer-level devicesPre-trained modelsSleep staging performanceSevere noise levelsEfficient training approachAdversarial trainingAdversarial noiseDomain shiftAdversarial transformationsAuxiliary modelDL modelsInput perturbationsTraining modelArbitrary noiseTesting stageEnhanced robustnessNoise signalsTraining approachTest environmentExperimental resultsNoiseSleep stagesRobustness
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 sequenceDeep learning-based GTV contouring modeling inter- and intra- observer variability in sarcomas
Marin T, Zhuo Y, Lahoud R, Tian F, Ma X, Xing F, Moteabbed M, Liu X, Grogg K, Shusharina N, Woo J, Lim R, Ma C, Chen Y, El Fakhri G. Deep learning-based GTV contouring modeling inter- and intra- observer variability in sarcomas. Radiotherapy And Oncology 2021, 167: 269-276. PMID: 34808228, PMCID: PMC8934266, DOI: 10.1016/j.radonc.2021.09.034.Peer-Reviewed Original ResearchMeSH KeywordsDeep LearningHumansObserver VariationRadiotherapy Planning, Computer-AssistedReproducibility of ResultsSarcomaSoft Tissue NeoplasmsConceptsGross tumor volumeRadiation therapy treatment planningGross tumor volume contoursGross tumor volume delineationTherapy treatment planningIntra-observer variabilityConsensus contoursGTV contoursPre-operative CT imagesSoft tissue sarcomasRadiation oncologistsTumor volumeBone sarcomasTreatment planningAccurate contoursCT imagesDelineation procedureSarcomaSoft tissueConfidence levelRadiationPatientsHausdorff distanceMultiple contoursX-ray
2020
Preclinical Validation of a Single-Scan Rest/Stress Imaging Technique for 13N-Ammonia Positron Emission Tomography Cardiac Perfusion Studies
Guehl N, Pelletier-Galarneau M, Wooten D, Guerrero J, Kas A, Normandin M, Fakhri G, Alpert N. Preclinical Validation of a Single-Scan Rest/Stress Imaging Technique for 13N-Ammonia Positron Emission Tomography Cardiac Perfusion Studies. Circulation Cardiovascular Imaging 2020, 13: e009407. PMID: 31959009, PMCID: PMC7205554, DOI: 10.1161/circimaging.119.009407.Peer-Reviewed Original ResearchConceptsMyocardial blood flowPerfusion imagingMyocardial perfusion imaging proceduresSCAN-ALeft anterior descending arteryDose of adenosineAbsolute myocardial blood flowStress perfusion imagingAnterior descending arteryCardiac perfusion studiesMyocardial blood flow measurementsBland-Altman analysisNonstationary kinetic modelPositron emission tomographyMeasurement of restMyocardial blood flow valuesPharmacological stressorDescending arteryPreclinical validationMyocardial blood flow estimatesSingle-scan acquisitionPerfusion studiesVariable dosesImaging sessionMicrosphere MBF measurements
2019
Autoradiography validation of novel tau PET tracer [F-18]-MK-6240 on human postmortem brain tissue
Aguero C, Dhaynaut M, Normandin M, Amaral A, Guehl N, Neelamegam R, Marquie M, Johnson K, El Fakhri G, Frosch M, Gomez-Isla T. Autoradiography validation of novel tau PET tracer [F-18]-MK-6240 on human postmortem brain tissue. Acta Neuropathologica Communications 2019, 7: 37. PMID: 30857558, PMCID: PMC6410510, DOI: 10.1186/s40478-019-0686-6.Peer-Reviewed Original ResearchConceptsIn vivo detection of neurofibrillary tanglesNeurofibrillary tanglesDetection of neurofibrillary tanglesAlzheimer's diseaseTDP-43Binds to neurofibrillary tanglesFrontotemporal lobar degeneration-tauOff-target bindingDNA-binding protein 43Binding patternsNon-Alzheimer tauopathiesHuman postmortem brain tissueTau aggregationPostmortem brain tissueBinding signalBinding targetsCerebral amyloid angiopathyIn vivo detectionB-amyloidNeurodegenerative diseasesHuman brain tissueTauTau positron emission tomographyBindingMK-6240
2016
Pharmacokinetic Evaluation of the Tau PET Radiotracer 18F-T807 (18F-AV-1451) in Human Subjects
Wooten D, Guehl N, Verwer E, Shoup T, Yokell D, Zubcevik N, Vasdev N, Zafonte R, Johnson K, Fakhri G, Normandin M. Pharmacokinetic Evaluation of the Tau PET Radiotracer 18F-T807 (18F-AV-1451) in Human Subjects. Journal Of Nuclear Medicine 2016, 58: 484-491. PMID: 27660144, PMCID: PMC5334185, DOI: 10.2967/jnumed.115.170910.Peer-Reviewed Original ResearchConceptsDistribution volume ratioTraumatic brain injuryMetabolite-corrected arterial input functionPET imagingPlasma radioactivity concentrationsTemporal cortexDynamic PET imagesTotal volume of distributionVolume of distributionTraumatic brain injury subjectsMesial temporal cortexArterial blood samplesPosterior cingulate gyrusFocal uptakeSUV ratioHuman subjectsArterial input functionPosterior corpus callosumBolus injectionPharmacokinetic evaluation
2015
National Electrical Manufacturers Association and Clinical Evaluation of a Novel Brain PET/CT Scanner
Grogg K, Toole T, Ouyang J, Zhu X, Normandin M, Li Q, Johnson K, Alpert N, Fakhri G. National Electrical Manufacturers Association and Clinical Evaluation of a Novel Brain PET/CT Scanner. Journal Of Nuclear Medicine 2015, 57: 646-652. PMID: 26697961, PMCID: PMC4818715, DOI: 10.2967/jnumed.115.159723.Peer-Reviewed Original ResearchMeSH KeywordsAnimalsBrainElectric Power SuppliesHumansNeuroimagingPhantoms, ImagingPositron-Emission TomographyReproducibility of ResultsSafetyScattering, RadiationConceptsNoise-equivalent count rateCount rateLoose cutsMaximum noise-equivalent counting rateSpatial resolutionDetector ringSilicon photomultipliersBrain phantomContrast recoveryAttenuation correctionPET/CT systemCrystal blockPET/CT scannerImage qualityRadial offsetNational Electrical Manufacturers AssociationActivity distributionUnique mobility capabilitiesAxial extentTransverse resolutionPhantomAxial resolutionActivity concentrationsHuman scansLayer 1 cm
2014
Towards 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 imagingPhantom
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
2010
Novel 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 Research
2008
Improved activity estimation with MC‐JOSEM versus TEW‐JOSEM in SPECT
Ouyang J, Fakhri G, Moore S. Improved activity estimation with MC‐JOSEM versus TEW‐JOSEM in SPECT. Medical Physics 2008, 35: 2029-2040. PMID: 18561679, PMCID: PMC2673642, DOI: 10.1118/1.2907561.Peer-Reviewed Original ResearchMeSH KeywordsAlgorithmsEquipment DesignImage Processing, Computer-AssistedIndium RadioisotopesLungModels, StatisticalMonte Carlo MethodPhantoms, ImagingRadiotherapy Planning, Computer-AssistedReproducibility of ResultsScattering, RadiationSoftwareTomography, Emission-Computed, Single-PhotonTomography, X-Ray ComputedConceptsMC-JOSEMWater-filled torso phantomMC scatter estimationTriple-energy-windowActivity estimationIterative reconstruction algorithmTorso phantomPhantom studyBackground compartmentScatter estimationActivity distributionAverage relative biasPhantomReconstruction algorithmActivity concentrationsSynthetic projectionsSphere locationScattering
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
Performance of a novel collimator for high‐sensitivity brain SPECT
Fakhri G, Ouyang J, Zimmerman R, Fischman A, Kijewski M. Performance of a novel collimator for high‐sensitivity brain SPECT. Medical Physics 2005, 33: 209-215. PMID: 16485427, DOI: 10.1118/1.2143140.Peer-Reviewed Original ResearchConceptsSphere activity concentrationNPW-SNRStandard collimatorSphere-to-background activity ratiosAttenuation of countsPhantom centerActivity concentrationsPoint spread functionCentral regionCollimatorPhantom studyStriatal phantomCylindrical backgroundResolution recoveryPhantomSpherical lesionsRamp filterCrystal surfaceSpread functionSignal-to-noise ratioCentral brain structuresFitting imageHealthy volunteersBrain SPECTSphere activityCollimator 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 ResearchCitratesComputer SimulationComputer-Aided DesignEquipment DesignEquipment Failure AnalysisGalliumHumansImage EnhancementImage Interpretation, Computer-AssistedModels, BiologicalNeoplasmsPhantoms, ImagingPositron-Emission TomographyRadiopharmaceuticalsReproducibility of ResultsSensitivity and SpecificityQuantitative 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 ResearchAdultAgedAged, 80 and overAlgorithmsComputer SimulationCoronary Artery DiseaseFeasibility StudiesFemaleHeartHumansImage Interpretation, Computer-AssistedMaleMiddle AgedModels, CardiovascularPositron-Emission TomographyRadiopharmaceuticalsReproducibility of ResultsRubidium RadioisotopesSensitivity and SpecificitySeverity of Illness Index
2000
Relative impact of scatter, collimator response, attenuation, and finite spatial resolution corrections in cardiac SPECT.
El Fakhri G, Buvat I, Benali H, Todd-Pokropek A, Di Paola R. Relative impact of scatter, collimator response, attenuation, and finite spatial resolution corrections in cardiac SPECT. Journal Of Nuclear Medicine 2000, 41: 1400-8. PMID: 10945534.Peer-Reviewed Original Research