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
B1 inhomogeneity‐corrected T1 mapping and quantitative magnetization transfer imaging via simultaneously estimating Bloch‐Siegert shift and magnetization transfer effects
Jang A, Han P, Ma C, Fakhri G, Wang N, Samsonov A, Liu F. B1 inhomogeneity‐corrected T1 mapping and quantitative magnetization transfer imaging via simultaneously estimating Bloch‐Siegert shift and magnetization transfer effects. Magnetic Resonance In Medicine 2023, 90: 1859-1873. PMID: 37427533, PMCID: PMC10528411, DOI: 10.1002/mrm.29778.Peer-Reviewed Original ResearchConceptsBloch-Siegert shiftBloch-SiegertMagnetization transfer effectsMonte Carlo simulationsSpin-lattice relaxationSpin-bath modelMagnetization transferBinary spin-bath modelCarlo simulationsProton fractionOff-resonance irradiationIn vivo brain studiesBloch simulationsPhantom experimentsMagnetizationEstimationTransmitted fieldQuantitative magnetization transferMethod performanceMT effectSignal equationSuper-resolution in brain positron emission tomography using a real-time motion capture system
Chemli Y, Tétrault M, Marin T, Normandin M, Bloch I, El Fakhri G, Ouyang J, Petibon Y. Super-resolution in brain positron emission tomography using a real-time motion capture system. NeuroImage 2023, 272: 120056. PMID: 36977452, PMCID: PMC10122782, DOI: 10.1016/j.neuroimage.2023.120056.Peer-Reviewed Original ResearchConceptsBrain positron emission tomographySuper-resolutionEvent-by-event basisReal-time motion capture systemSR reconstruction methodTracking cameraVisualization of small structuresPET reconstruction algorithmMoving phantomMeasure target motionLine profilesPET/CT scannerMeasured shiftsImprove image resolutionMotion capture systemMotion tracking devicePositron emission tomographyReconstruction algorithmSpatial resolutionMeasured linesPhantomReal-timeEstimation frameworkIncreased spatial resolutionReconstruction method
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 sequence
2020
Accelerated J‐resolved 1H‐MRSI with limited and sparse sampling of (‐space
Tang L, Zhao Y, Li Y, Guo R, Clifford B, Fakhri G, Ma C, Liang Z, Luo J. Accelerated J‐resolved 1H‐MRSI with limited and sparse sampling of (‐space. Magnetic Resonance In Medicine 2020, 85: 30-41. PMID: 32726510, PMCID: PMC7992196, DOI: 10.1002/mrm.28413.Peer-Reviewed Original ResearchMR‐based PET attenuation correction using a combined ultrashort echo time/multi‐echo Dixon acquisition
Han P, Horng D, Gong K, Petibon Y, Kim K, Li Q, Johnson K, Fakhri G, Ouyang J, Ma C. MR‐based PET attenuation correction using a combined ultrashort echo time/multi‐echo Dixon acquisition. Medical Physics 2020, 47: 3064-3077. PMID: 32279317, PMCID: PMC7375929, DOI: 10.1002/mp.14180.Peer-Reviewed Original ResearchConceptsLinear attenuation coefficientPositron emission tomography attenuation correctionPhysical compartmental modelAttenuation correctionShort T<sub>2</sub> componentPET attenuation correctionRadial k-space trajectoryMagnetic resonance (MR)-based methodK-space trajectoriesRadial trajectoryK-spaceAttenuation coefficientDixon acquisitionsPositron emission tomographyWhole white matterMuting methodImage reconstructionImaging speedMR signalMRAC methodPositron emission tomography imagingCorrectionGray matter regionsPhantomMatter regionsA Radio-Nano-Platform for T1/T2 Dual-Mode PET-MR Imaging
Gholami Y, Yuan H, Wilks M, Maschmeyer R, Normandin M, Josephson L, Fakhri G, Kuncic Z. A Radio-Nano-Platform for T1/T2 Dual-Mode PET-MR Imaging. International Journal Of Nanomedicine 2020, 15: 1253-1266. PMID: 32161456, PMCID: PMC7049573, DOI: 10.2147/ijn.s241971.Peer-Reviewed Original ResearchConceptsLine spread functionPET-MR imagingSignal-to-noise ratioFull-width half-maximum (FWHMPET-MRHalf-maximum (FWHMSpatial resolutionTransmission electron microscopyImage quality gainSimultaneous positron emission tomographyContrast-enhanced diagnostic imagingAtom adsorptionPhantom imagesPositron emission tomographySpatial resolution of MRHybrid PET-MRRadio-isotopesSpread functionMulti-modal imaging techniquesSensitivity of positron emission tomographyMagnetic resonanceCo-registeredTransmission electron microscopy analysisSuper paramagnetic iron oxide nanoparticlesContrast agents
2019
Body motion detection and correction in cardiac PET: Phantom and human studies
Sun T, Petibon Y, Han P, Ma C, Kim S, Alpert N, Fakhri G, Ouyang J. Body motion detection and correction in cardiac PET: Phantom and human studies. Medical Physics 2019, 46: 4898-4906. PMID: 31508827, PMCID: PMC6842053, DOI: 10.1002/mp.13815.Peer-Reviewed Original ResearchMeSH KeywordsArtifactsFluorodeoxyglucose F18HeartHumansImage Processing, Computer-AssistedMovementPhantoms, ImagingPositron-Emission TomographyConceptsList-mode dataMotion-compensated image reconstructionMotion correctionCenter of massPET list-mode dataMotion correction methodMotion detectionMotion estimationImage reconstructionPatient body motionDegrade image qualityNonrigid registrationImage qualityMotion transformationCoincident distributionBody motion detectionCardiac positron emission tomographyBack-projection techniqueCovariance matrixImage volumesBody motionPositron emission tomographyBack-projectionReference framePhantomPerformance evaluation of the 5‐Ring GE Discovery MI PET/CT system using the national electrical manufacturers association NU 2‐2012 Standard
Pan T, Einstein S, Kappadath S, Grogg K, Gomez C, Alessio A, Hunter W, Fakhri G, Kinahan P, Mawlawi O. Performance evaluation of the 5‐Ring GE Discovery MI PET/CT system using the national electrical manufacturers association NU 2‐2012 Standard. Medical Physics 2019, 46: 3025-3033. PMID: 31069816, PMCID: PMC7251507, DOI: 10.1002/mp.13576.Peer-Reviewed Original ResearchMeSH KeywordsHumansPhantoms, ImagingPositron Emission Tomography Computed TomographyReference StandardsConceptsAxial field-of-viewPeak noise-equivalent count rateNoise-equivalent count rateField of viewCount ratePET performanceNational Electrical Manufacturers Association NU-2Transaxial field of viewPET/CT systemTime resolutionMean energy resolutionConventional photomultiplier tubesCount rate performanceImage quality phantomSpatial resolution measurementsFiltered back projection algorithmImage qualityEnergy resolutionAcquisition timeNU 2Count lossDetector designPhotomultiplier tubeMean energyPET/MR systems
2018
A novel depth-of-interaction rebinning strategy for ultrahigh resolution PET
Kim K, Dutta J, Groll A, Fakhri G, Meng L, Li Q. A novel depth-of-interaction rebinning strategy for ultrahigh resolution PET. Physics In Medicine And Biology 2018, 63: 165011. PMID: 30040073, PMCID: PMC6375090, DOI: 10.1088/1361-6560/aad58c.Peer-Reviewed Original ResearchMeSH KeywordsAlgorithmsAnimalsBrainImage Processing, Computer-AssistedPhantoms, ImagingPositron-Emission TomographyConceptsDepth of interactionReconstructed imagesAlternating direction methodReconstructed image qualityPoisson log-likelihoodImage qualitySub-sampling methodPositron emission tomography systemReduce noise effectsDOI layersReconstruction frameworkDetector pixel sizePoint source experimentsQuadratic surrogatesCdZnTe detectorsAnimal positron emission tomographyLog-likelihoodDirection methodSmall animal positron emission tomographySource ExperimentPhoton countingRebinning methodSystem matrixNoise effectsSinogramJoint reconstruction of rest/stress myocardial perfusion SPECT
Lai X, Petibon Y, Fakhri G, Ouyang J. Joint reconstruction of rest/stress myocardial perfusion SPECT. Physics In Medicine And Biology 2018, 63: 135019. PMID: 29897044, PMCID: PMC6245543, DOI: 10.1088/1361-6560/aacc2f.Peer-Reviewed Original ResearchConceptsMyocardial perfusion imagingSingle photon emission computed tomographyReversible defectsSignal-to-noise ratioRest/stress SPECT myocardial perfusion imagingSPECT myocardial perfusion imagingConventional subtraction methodDefect detectionJoint methodPhoton emission computed tomographySubtraction methodReverse mappingClinical dose levelsEmission computed tomographyImprove defect detectionLow noiseNon-invasive assessmentClinical dosePerfusion defectsReduced doseImprove radiologists' performanceReconstruction frameworkRest imagesPerfusion imagingDose levelsPenalized PET Reconstruction Using Deep Learning Prior and Local Linear Fitting
Kim K, Wu D, Gong K, Dutta J, Kim J, Son Y, Kim H, Fakhri G, Li Q. Penalized PET Reconstruction Using Deep Learning Prior and Local Linear Fitting. IEEE Transactions On Medical Imaging 2018, 37: 1478-1487. PMID: 29870375, PMCID: PMC6375088, DOI: 10.1109/tmi.2018.2832613.Peer-Reviewed Original ResearchConceptsDeep learningDenoising convolutional neural networkConvolutional neural networkDeep learning-basedPerformance of iterative reconstructionPotential of deep learningDeep networksNoise levelLearning-basedReconstruction frameworkDegradation of performanceNeural networkDnCNNMedical imagesDownsampled dataFitness functionPoisson thinningFull-dose imagesLow dose imagesNoise conditionsNetworkImage qualityPET reconstructionDose imagesDeep
2017
A minimum-phase Shinnar-Le Roux spectral-spatial excitation RF pulse for simultaneous water and lipid suppression in 1H-MRSI of body extremities
Han P, Ma C, Deng K, Hu S, Jee K, Ying K, Chen Y, Fakhri G. A minimum-phase Shinnar-Le Roux spectral-spatial excitation RF pulse for simultaneous water and lipid suppression in 1H-MRSI of body extremities. Magnetic Resonance Imaging 2017, 45: 18-25. PMID: 28917812, PMCID: PMC5709164, DOI: 10.1016/j.mri.2017.09.008.Peer-Reviewed Original ResearchMeSH KeywordsAlgorithmsHumansImage Processing, Computer-AssistedLegLipidsMagnetic Resonance SpectroscopyMuscle, SkeletalPhantoms, ImagingProtonsWaterJoint reconstruction of Ictal/inter‐ictal SPECT data for improved epileptic foci localization
Rakvongthai Y, Fahey F, Borvorntanajanya K, Tepmongkol S, Vutrapongwatana U, Zukotynski K, Fakhri G, Ouyang J. Joint reconstruction of Ictal/inter‐ictal SPECT data for improved epileptic foci localization. Medical Physics 2017, 44: 1437-1444. PMID: 28211105, PMCID: PMC5462456, DOI: 10.1002/mp.12167.Peer-Reviewed Original ResearchConceptsSPECT reconstruction methodDifferential imagingLow-noise datasetConventional subtraction methodLesion contrastSPECT projection dataEpileptic focus localizationHoffman phantomPatient studiesReconstruction methodJoint methodSPECT projectionsHead phantomPhantom locationsSubtraction methodPhantom studyNuclear medicine physiciansAttenuation backgroundPhantomConventional subtraction approachFocus localizationConventional subtractionReceiver operating characteristicLow noiseProjection dataFeasibility study of using fall‐off gradients of early and late PET scans for proton range verification
Cho J, Grogg K, Min C, Zhu X, Paganetti H, Lee H, Fakhri G. Feasibility study of using fall‐off gradients of early and late PET scans for proton range verification. Medical Physics 2017, 44: 1734-1746. PMID: 28273345, PMCID: PMC5462437, DOI: 10.1002/mp.12191.Peer-Reviewed Original ResearchMeSH KeywordsFeasibility StudiesHumansMonte Carlo MethodPhantoms, ImagingPositron-Emission TomographyProtonsConceptsProton range verificationProton rangeMonte Carlo simulationsRange verificationFall-offIn-room positron emission tomographyCarlo simulationsResidual proton rangeDose fall-offPostirradiation delayPositron emission tomography imagingSOBP beamProton beamPositron emission tomographyPositron emission tomography scanPhantom studyIn-roomFunction of depthPhantomProtonOff-setMonteAcquisition timeBeamPositron emission tomography signal
2016
Investigation of cone-beam CT image quality trade-off for image-guided radiation therapy
Bian J, Sharp G, Park Y, Ouyang J, Bortfeld T, Fakhri G. Investigation of cone-beam CT image quality trade-off for image-guided radiation therapy. Physics In Medicine And Biology 2016, 61: 3317-3346. PMID: 27032676, DOI: 10.1088/0031-9155/61/9/3317.Peer-Reviewed Original ResearchConceptsImage-guided radiation therapyCone-beam CTFiltered-backprojectionImage quality trade-offConventional filtered-backprojectionShort-scan reconstructionsFiltered-backprojection algorithmFan-beam reconstructionTV-based algorithmIterative reconstruction algorithmCatphan phantomRadiation therapyAngular rangeTotal-variationOptimal exposure levelClinical scannerScanning configurationReconstruction algorithmImaging conditionsCatphanPhantomExposure levelsTherapyConfigurationRange
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 ResearchConceptsNoise-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 cmContinuous MR bone density measurement using water- and fat-suppressed projection imaging (WASPI) for PET attenuation correction in PET-MR
Huang C, Ouyang J, Reese T, Wu Y, Fakhri G, Ackerman J. Continuous MR bone density measurement using water- and fat-suppressed projection imaging (WASPI) for PET attenuation correction in PET-MR. Physics In Medicine And Biology 2015, 60: n369-n381. PMID: 26405761, PMCID: PMC4607313, DOI: 10.1088/0031-9155/60/20/n369.Peer-Reviewed Original ResearchConceptsAttenuation correctionUltrashort echo timeMR-based attenuation correctionProjection imagesPET attenuation correctionMR attenuation correctionPET-MRPulse sequenceEcho timeDensity variationsPET imagingCorrectionBone density variationWASPIDensity measurementsAttenuation variationsPhantomMR sequencesLack of signalPulseAttenuationPulmonary imaging using respiratory motion compensated simultaneous PET/MR
Dutta J, Huang C, Li Q, El Fakhri G. Pulmonary imaging using respiratory motion compensated simultaneous PET/MR. Medical Physics 2015, 42: 4227-4240. PMID: 26133621, PMCID: PMC4474958, DOI: 10.1118/1.4921616.Peer-Reviewed Original ResearchConceptsRespiratory motionContrast-to-noise ratioClinical patient studiesPulse sequenceHigh-intensity featuresXCAT studyLow proton densityXCAT simulationPatient studiesXCAT phantomAttenuation mapBiograph mMRComplete data acquisitionSimultaneous PET/MRNonrigid registrationPET/MR scannersPET/magnetic resonanceMagnetic susceptibilityProton densityQuantitative accuracyRelaxation timePulmonary imagingLung lesionsBlurring artifactsDeformation fieldMapping 15O Production Rate for Proton Therapy Verification
Grogg K, Alpert N, Zhu X, Min C, Testa M, Winey B, Normandin M, Shih H, Paganetti H, Bortfeld T, Fakhri G. Mapping 15O Production Rate for Proton Therapy Verification. International Journal Of Radiation Oncology • Biology • Physics 2015, 92: 453-459. PMID: 25817530, PMCID: PMC4431894, DOI: 10.1016/j.ijrobp.2015.01.023.Peer-Reviewed Original ResearchConceptsDecay constantProton treatment planningMonte Carlo predictionsProton therapyPhantom materialTreatment deliveryPhantomThigh activityPositron emission tomographyProduction rateDynamic PET measurementsTreatment planningRabbit thigh muscleClearance rateProtonIsotopesChanges due to therapyRadionuclide speciesOxygen-15ConstantDecayImaging targetsMontePositronEffects of perfusion