2015
In Acute Stroke, Can CT Perfusion-Derived Cerebral Blood Volume Maps Substitute for Diffusion-Weighted Imaging in Identifying the Ischemic Core?
Copen W, Morais L, Wu O, Schwamm L, Schaefer P, González R, Yoo A. In Acute Stroke, Can CT Perfusion-Derived Cerebral Blood Volume Maps Substitute for Diffusion-Weighted Imaging in Identifying the Ischemic Core? PLOS ONE 2015, 10: e0133566. PMID: 26193486, PMCID: PMC4508041, DOI: 10.1371/journal.pone.0133566.Peer-Reviewed Original ResearchConceptsComputed tomography perfusion imagingDiffusion-weighted magnetic resonance imagingCerebral blood volumeInfarct volumeSensitivity/specificityCBV mapsDWI lesionsIschemic coreCore lesionsDWI-positive patientsRegional cerebral blood volumeAcute ischemic strokeFinal infarct volumeTreatment of patientsTomography perfusion imagingPresence of infarctionMagnetic resonance imagingDiffusion-weighted imagingAcute strokeIschemic strokeSymptom onsetLesion volumeIndividual patientsInter-rater agreementPatients
2014
Exposing Hidden Truncation-Related Errors in Acute Stroke Perfusion Imaging
Copen W, Deipolyi A, Schaefer P, Schwamm L, González R, Wu O. Exposing Hidden Truncation-Related Errors in Acute Stroke Perfusion Imaging. American Journal Of Neuroradiology 2014, 36: 638-645. PMID: 25500309, PMCID: PMC7964314, DOI: 10.3174/ajnr.a4186.Peer-Reviewed Original ResearchConceptsPerfusion scanVolume of lesionsScan durationSymptom onsetAcute infarctsHemodynamic measurementsLesion reversalClinical trialsLesion volumePatient managementPerfusion MRPerfusion imagingInjected contrast agentPerfusion imagesPatient CTLesionsDurationMTTCTLong scan durationScansContrast agentsShort scan durationTmaxPerfusion estimates
2012
Rapid identification of a major diffusion/perfusion mismatch in distal internal carotid artery or middle cerebral artery ischemic stroke
Hakimelahi R, Yoo A, He J, Schwamm L, Lev M, Schaefer P, González R. Rapid identification of a major diffusion/perfusion mismatch in distal internal carotid artery or middle cerebral artery ischemic stroke. BMC Neurology 2012, 12: 132. PMID: 23121836, PMCID: PMC3519648, DOI: 10.1186/1471-2377-12-132.Peer-Reviewed Original ResearchConceptsDiffusion/perfusion mismatchDWI lesion volumeInternal carotid arteryLesion volumePerfusion mismatchConsecutive patientsCarotid arteryMiddle cerebral artery ischemic strokeDiffusion/perfusion MRITerminal internal carotid arteryProximal middle cerebral arteryDistal internal carotid arteryLarger mismatch volumeProximal MCA occlusionMiddle cerebral arteryDiffusion lesion volumeSame inclusion criteriaTerminal ICAArtery occlusionIschemic strokeMCA occlusionStroke onsetCerebral arteryStroke patientsPatient assessment
2010
Combining Acute Diffusion-Weighted Imaging and Mean Transmit Time Lesion Volumes With National Institutes of Health Stroke Scale Score Improves the Prediction of Acute Stroke Outcome
Yoo A, Barak E, Copen W, Kamalian S, Gharai L, Pervez M, Schwamm L, González R, Schaefer P. Combining Acute Diffusion-Weighted Imaging and Mean Transmit Time Lesion Volumes With National Institutes of Health Stroke Scale Score Improves the Prediction of Acute Stroke Outcome. Stroke 2010, 41: 1728-1735. PMID: 20595665, DOI: 10.1161/strokeaha.110.582874.Peer-Reviewed Original ResearchMeSH KeywordsAdultAgedAged, 80 and overBrainBrain IschemiaDiffusion Magnetic Resonance ImagingFemaleHumansImage Processing, Computer-AssistedMaleMiddle AgedNational Institutes of Health (U.S.)Predictive Value of TestsPrognosisROC CurveSeverity of Illness IndexStatistics, NonparametricStrokeTime FactorsTreatment OutcomeUnited StatesConceptsAcute diffusion-weighted imagingDiffusion-weighted imagingAcute ischemic strokeNIHSS scorePoor outcomeLesion volumeIschemic strokeRankin ScaleBetter outcomesHealth Stroke Scale scoreAcute stroke outcomeDWI lesion volumeBaseline NIHSS scoreHealth Stroke ScaleStroke Scale scoreLower NIHSS scoreModified Rankin ScaleNational InstituteQuantitative diffusion-weighted imagingMTT volumesStroke ScaleStroke outcomeSymptom onsetClinical outcomesPrognostic yield
2009
Existence of the Diffusion-Perfusion Mismatch within 24 Hours after Onset of Acute Stroke: Dependence on Proximal Arterial Occlusion
Copen W, Rezai Gharai L, Barak E, Schwamm L, Wu O, Kamalian S, Gonzalez R, Schaefer P. Existence of the Diffusion-Perfusion Mismatch within 24 Hours after Onset of Acute Stroke: Dependence on Proximal Arterial Occlusion. Radiology 2009, 250: 878-86. PMID: 19164120, DOI: 10.1148/radiol.2503080811.Peer-Reviewed Original ResearchConceptsProximal arterial occlusionAcute ischemic stroke trialsIschemic stroke trialsAcute strokeArterial occlusionStroke trialsLesion volumePerfusion-weighted magnetic resonance imagesDiffusion-perfusion mismatchMean transit time mapsTransit time mapsHIPAA-compliant studyPAO patientsAngiographic evidenceStroke onsetDose escalationTomographic angiographyEligibility criteriaPatientsInstitutional reviewMagnetic resonance imagesMR angiographyDesmoteplaseSignificant differencesAngiography
2008
Intravenous desmoteplase in patients with acute ischaemic stroke selected by MRI perfusion–diffusion weighted imaging or perfusion CT (DIAS-2): a prospective, randomised, double-blind, placebo-controlled study
Hacke W, Furlan A, Al-Rawi Y, Davalos A, Fiebach J, Gruber F, Kaste M, Lipka L, Pedraza S, Ringleb P, Rowley H, Schneider D, Schwamm L, Leal J, Söhngen M, Teal P, Wilhelm-Ogunbiyi K, Wintermark M, Warach S. Intravenous desmoteplase in patients with acute ischaemic stroke selected by MRI perfusion–diffusion weighted imaging or perfusion CT (DIAS-2): a prospective, randomised, double-blind, placebo-controlled study. The Lancet Neurology 2008, 8: 141-150. PMID: 19097942, PMCID: PMC2730486, DOI: 10.1016/s1474-4422(08)70267-9.Peer-Reviewed Original ResearchMeSH KeywordsAdolescentAdultAgedAged, 80 and overBrain IschemiaCerebral HemorrhageDouble-Blind MethodFemaleFibrinolytic AgentsHumansInjections, IntravenousMagnetic Resonance ImagingMaleMiddle AgedPerfusionPlasminogen ActivatorsProspective StudiesSample SizeStrokeTomography, X-Ray ComputedTreatment FailureYoung AdultConceptsSymptomatic intracranial hemorrhageClinical response rateAcute ischemic strokeDiffusion-weighted imagingResponse rateNIHSS scoreIschemic strokeIntracranial hemorrhageLesion volumeDay 90Mortality ratePerfusion imagingScale scoreHealth Stroke Scale scoreMedian baseline NIHSS scoreModified Rankin Scale scoreMagnetic resonance perfusion imagingComposite of improvementBaseline NIHSS scorePlacebo-controlled studyStroke Scale scoreDose-ranging studyRankin Scale scoreSymptoms of strokeOnset of strokeQuantitative Assessment of Core/Penumbra Mismatch in Acute Stroke
Schaefer P, Barak E, Kamalian S, Gharai L, Schwamm L, Gonzalez R, Lev M. Quantitative Assessment of Core/Penumbra Mismatch in Acute Stroke. Stroke 2008, 39: 2986-2992. PMID: 18723425, DOI: 10.1161/strokeaha.107.513358.Peer-Reviewed Original ResearchConceptsCT perfusionPatient selectionInfarct coreAcute middle cerebral artery strokeMiddle cerebral artery strokePreferred imaging methodStroke clinical trialsAcute strokeArtery strokeStroke trialsTrial enrollmentClinical trialsLesion volumeMR perfusionIschemic regionBlood volumeTime abnormalitiesVolume thresholdLesion sizeQuantitative CTPerfusionAdvanced MRCT coverageLesionsMR diffusionRole of Recanalization in Acute Stroke Outcome: Rationale for a CT Angiogram-Based “Benefit of Recanalization” Model
Rosenthal E, Schwamm L, Roccatagliata L, Coutts S, Demchuk A, Schaefer P, Gonzalez R, Hill M, Halpern E, Lev M. Role of Recanalization in Acute Stroke Outcome: Rationale for a CT Angiogram-Based “Benefit of Recanalization” Model. American Journal Of Neuroradiology 2008, 29: 1471-1475. PMID: 18599577, PMCID: PMC8119059, DOI: 10.3174/ajnr.a1153.Peer-Reviewed Original ResearchConceptsOnly independent predictorLesion volumeComplete recanalizationRecanalization statusClinical outcomesNIHSS scoreIndependent predictorsIncomplete recanalizationCTA-SI Alberta Stroke Program Early CT ScoreAcute middle cerebral artery strokeAlberta Stroke Program Early CT ScoreHealth Stroke Scale scoreMedian admission NIHSS scoreMiddle cerebral artery strokeCT angiographic source imagesAcute stroke outcomeAdmission National InstitutesBenefit of recanalizationEarly successful recanalizationMCA M1 occlusionRole of recanalizationStroke Scale scoreAdmission NIHSS scoreMRS score 0CT/CTA
2005
Hypoattenuation on CT angiographic source images predicts risk of intracerebral hemorrhage and outcome after intra-arterial reperfusion therapy.
Schwamm L, Rosenthal E, Swap C, Rosand J, Rordorf G, Buonanno F, Vangel M, Koroshetz W, Lev M. Hypoattenuation on CT angiographic source images predicts risk of intracerebral hemorrhage and outcome after intra-arterial reperfusion therapy. American Journal Of Neuroradiology 2005, 26: 1798-803. PMID: 16091532, PMCID: PMC7975152.Peer-Reviewed Original ResearchMeSH KeywordsAgedArterial Occlusive DiseasesBasilar ArteryCerebral AngiographyCerebral HemorrhageCerebral InfarctionFemaleFibrinolytic AgentsHematomaHumansMaleMiddle AgedMiddle Cerebral ArteryPredictive Value of TestsRetrospective StudiesRisk AssessmentTissue Plasminogen ActivatorTomography, X-Ray ComputedConceptsIntra-arterial reperfusion therapyHemorrhagic transformationPoor clinical outcomeCTA source imagesReperfusion therapyClinical outcomesCT angiographic source imagesCatheter-based reperfusionReal-time risk stratificationSymptomatic hemorrhagic transformationReceiver operator characteristic curveBlood glucose levelsOperator characteristic curveAxial source imagesNormal contralateral tissueConsecutive patientsVascular insufficiencyIntracerebral hemorrhageRisk stratificationStroke patientsPoor outcomeSignificant complicationsRisk factorsContralateral tissueLesion volume
2004
Characterization and evolution of diffusion MR imaging abnormalities in stroke patients undergoing intra-arterial thrombolysis.
Schaefer P, Hassankhani A, Putman C, Sorensen A, Schwamm L, Koroshetz W, Gonzalez R. Characterization and evolution of diffusion MR imaging abnormalities in stroke patients undergoing intra-arterial thrombolysis. American Journal Of Neuroradiology 2004, 25: 951-7. PMID: 15205129, PMCID: PMC7975652.Peer-Reviewed Original ResearchConceptsIntra-arterial thrombolysisDiffusion-weighted imagingDWI findingsDWI ratioADC ratioReperfusion therapyAcute strokeApparent diffusion coefficientInitial diffusion-weighted imagingPretreatment diffusion-weighted imagingADC valuesRespective mean changesEventual infarctionAcute occlusionAnterior circulationStroke patientsLesion volumeMean changePatientsThrombolysisLesion growthMR imagingTissue viabilityLesionsInfarction
2002
Anatomy of Stroke, Part I
Caviness V, Makris N, Montinaro E, Sahin N, Bates J, Schwamm L, Caplan D, Kennedy D. Anatomy of Stroke, Part I. Stroke 2002, 33: 2549-2556. PMID: 12411641, DOI: 10.1161/01.str.0000036083.90045.08.Peer-Reviewed Original ResearchConceptsMCA territoryVolumetric analysisDistribution of infarctsTopography of infarctionTreatment of strokePerfusion-weighted imagingCorrelation of outcomesEmbolic strokeAcute eventClinical correlatesUnderlying pathophysiologyVascular territoriesLesion volumeStroke lesionsClinical diagnosisStrokeTherapeutic agentsMRINeuroanatomic structuresInfarctsTopographic patternsInvolvementPotential benefitsPerfusion compartmentsInfarction
2001
Utility of Perfusion-Weighted CT Imaging in Acute Middle Cerebral Artery Stroke Treated With Intra-Arterial Thrombolysis:
Lev M, Segal A, Farkas J, Hossain S, Putman C, Hunter G, Budzik R, Harris G, Buonanno F, Ezzeddine M, Chang Y, Koroshetz W, Gonzalez R, Schwamm L. Utility of Perfusion-Weighted CT Imaging in Acute Middle Cerebral Artery Stroke Treated With Intra-Arterial Thrombolysis:. Stroke 2001, 32: 2021-2028. PMID: 11546891, DOI: 10.1161/hs0901.095680.Peer-Reviewed Original ResearchConceptsFinal infarct volumeAcute middle cerebral artery strokeNIH Stroke Scale scoreMiddle cerebral artery strokeMCA stem occlusionIntra-arterial thrombolysisStroke Scale scoreComplete recanalizationClinical outcomesInfarct volumeLesion volumeArtery strokeOutcome groupAdmission NIH Stroke Scale scoreInitial NIH Stroke Scale scoreScale scoreEarly complete recanalizationFinal lesion volumeUtility of perfusionPoor outcome groupModified Rankin ScalePoor clinical outcomeRankin ScaleStroke onsetConsecutive patients
1999
Hyperacute Stroke: Simultaneous Measurement of Relative Cerebral Blood Volume, Relative Cerebral Blood Flow, and Mean Tissue Transit Time
Sorensen A, Copen W, Ostergaard L, Buonanno F, Gonzalez R, Rordorf G, Rosen B, Schwamm L, Weisskoff R, Koroshetz W. Hyperacute Stroke: Simultaneous Measurement of Relative Cerebral Blood Volume, Relative Cerebral Blood Flow, and Mean Tissue Transit Time. Radiology 1999, 210: 519-27. PMID: 10207439, DOI: 10.1148/radiology.210.2.r99fe06519.Peer-Reviewed Original ResearchConceptsRelative cerebral blood flowCerebral blood flowRelative cerebral blood volumeCerebral blood volumeBlood flowBlood volumeTissue transit timeLesion volumeMR imagingDiffusion findingsAcute lesion volumesCompensatory hemodynamic responseHemodynamic MR imagingCerebral ischemic strokeOnset of symptomsInitial blood flowAltered blood flowBlood volume mapsFunctional magnetic resonance imagingMagnetic resonance imagingTransit time mapsBlood flow mapsInitial blood volumeInfarct volumeHemodynamic abnormalities
1998
Time Course of Lesion Development in Patients With Acute Stroke
Schwamm L, Koroshetz W, Sorensen A, Wang B, Copen W, Budzik R, Rordorf G, Buonanno F, Schaefer P, Gonzalez R. Time Course of Lesion Development in Patients With Acute Stroke. Stroke 1998, 29: 2268-2276. PMID: 9804633, DOI: 10.1161/01.str.29.11.2268.Peer-Reviewed Original ResearchConceptsApparent diffusion coefficient ratioDWI lesion volumeInitial DWI lesion volumeAcute ischemic strokeT2 lesion volumeLesion volumeNeurological outcomeIschemic strokeDiffusion-weighted imaging (DWI) lesion volumeHealth Stroke Scale scoreFinal lesion volumeImaging Lesion VolumeMaximum lesion volumePatients' neurological outcomeProgressive ischemic injurySecond scanStroke Scale scoreAcute stroke patientsSecondary pathophysiological processesAcute strokeStroke onsetSymptom onsetNeurological examinationInitial imagingIschemic injury