Ischemic Attack, TransientStrokeCerebrovascular DisordersCarotid StenosisEndarterectomy, CarotidAspirinCarotid Artery DiseasesRecurrenceCarotid Artery, InternalBrain IschemiaRisk FactorsIntracranial Embolism and ThrombosisProspective StudiesCerebral InfarctionIntracranial EmbolismFollow-Up StudiesCerebral AngiographyDipyridamoleTime FactorsUltrasonography, Doppler, TranscranialPlatelet Aggregation InhibitorsTreatment OutcomeMagnetic Resonance AngiographyAtrial FibrillationEchocardiography, TransesophagealCarotid ArteriesRisk AssessmentAnticoagulantsGreat BritainReferral and ConsultationPrognosisTomography, X-Ray ComputedFibrinolytic AgentsCerebrovascular CirculationRetrospective StudiesSeverity of Illness IndexEnglandPatient SelectionPredictive Value of TestsCohort StudiesAge FactorsIncidenceVertebrobasilar InsufficiencyEmbolismMyocardial IschemiaAcute DiseaseMyocardial InfarctionCardiovascular DiseasesEndarterectomyMagnetic Resonance ImagingIntracranial ArteriosclerosisComplement Membrane Attack ComplexMigraine DisordersAmaurosis FugaxIschemiaIntracranial Arterial DiseasesNeurologyMoyamoya DiseaseSecondary PreventionCerebral HemorrhageCalciumCerebral ArteriesSulfinpyrazoneRiskSeptember 11 Terrorist AttacksBrain