Lesson 1Perfusion imaging interpretation: core vs penumbra, Tmax, CBF, CBV thresholds and pitfallsThis part explains CT and MR perfusion interpretation, separating core from penumbra using CBF, CBV, and Tmax maps, looking at common number thresholds, differences between vendors, artefacts, and clinical pitfalls that can mislead treatment choices.
Physiologic basis of core and penumbraTmax, CBF, and CBV map interpretationCommon numeric thresholds and caveatsArtefacts, motion, and truncation errorsChronic infarct and leukoaraiosis pitfallsLesson 2Guidelines and decision thresholds: major society recommendations for imaging selection and treatment windowsThis part summarises major guideline recommendations for acute stroke imaging, including time windows for IV thrombolysis and thrombectomy, imaging-based selection beyond standard windows, and how to apply decision thresholds in everyday practice.
Key AHA/ASA and ESO imaging guidanceImaging criteria for IV thrombolysisImaging criteria for thrombectomyLate-window and wake-up stroke imagingReconciling guidelines with local practiceLesson 3Communication with stroke team: phrasing for thrombolysis and thrombectomy eligibility, recommended next imaging and monitoringThis part focuses on short, high-impact talk with the stroke team, including standard phrasing for thrombolysis and thrombectomy eligibility, statements on uncertainty, recommended next imaging, and advice on monitoring and repeat studies.
Key elements of the stroke phone reportPhrasing eligibility for IV thrombolysisPhrasing eligibility for thrombectomyRecommending next imaging stepsDocumenting uncertainty and follow-upLesson 4MRI protocols for hyperacute stroke: DWI, ADC, FLAIR, SWI, TOF/MRA, perfusion MRI parametersThis part explains MRI protocol design for hyperacute stroke, detailing DWI and ADC for core, FLAIR for onset estimation, SWI for haemorrhage and thrombus, TOF/MRA for vessels, and perfusion MRI parameters suited to time-critical decisions.
Optimising DWI and ADC for ischemic coreFLAIR mismatch and stroke onset estimationSWI for microbleeds and susceptibility vessel signTOF and contrast MRA for vessel imagingPerfusion MRI: sequence choice and timingLesson 5Reporting structure for stroke code: critical findings, side and vascular territory, estimated core/penumbra, time-sensitive recommendationsThis part outlines a structured stroke code report, stressing clear description of haemorrhage, ischemic core and penumbra, occlusion site, side and vascular territory, and clear, time-sensitive recommendations for thrombolysis, thrombectomy, and follow-up imaging.
Standardised report headings and sequenceDocumenting haemorrhage and ischemic coreSide, vascular territory, and ASPECTS scoringStating thrombectomy and lysis eligibilityTime-stamped, actionable recommendationsLesson 6CT protocols: slice thickness, reconstruction, contrast timing for CTA, coverage for perfusionThis part reviews noncontrast CT, CTA, and CT perfusion setup in acute stroke, focusing on slice thickness, reconstruction kernels, contrast bolus timing, and perfusion coverage to balance speed, radiation dose, and diagnostic accuracy.
Noncontrast CT slice thickness and kernelsCTA acquisition timing and contrast bolusCT perfusion coverage and slab selectionRadiation dose, ASIR, and artefact reductionMotion management and patient positioningLesson 7Selecting emergency imaging: noncontrast CT, CT angiography, CT perfusion and MRI alternativesThis part reviews how to select emergency imaging pathways, comparing noncontrast CT, CTA, CT perfusion, and MRI options based on time from onset, patient stability, contraindications, and local resources to create efficient, evidence-based algorithms.
Baseline noncontrast CT indicationsWhen to add CTA in the first scanRole of CT perfusion in triageWhen MRI is preferred or essentialBuilding site-specific imaging algorithmsLesson 8Vascular occlusion assessment: site of occlusion, collateral status, thrombus length and clot burden scoreThis part explains systematic assessment of vascular occlusion, including identification of occlusion site, clot length, collateral circulation, and clot burden scores on CTA and MRA, and how these factors influence thrombectomy decisions and prognosis.
Identifying proximal versus distal occlusionsMeasuring thrombus length on CTACollateral grading systems and scoringClot burden score and prognosisImaging predictors of recanalisationLesson 9False negatives and mimics: seizure, migraine, hypoglycemia, posterior fossa limitations and strategies to reduce errorsThis part addresses false negatives and stroke mimics, including seizure, migraine, hypoglycaemia, functional disorders, and posterior fossa strokes, and presents imaging strategies and protocol adjustments to reduce diagnostic errors in the hyperacute setting.
Common clinical and imaging stroke mimicsSeizure and postictal imaging appearancesMigraine aura and perfusion abnormalitiesPosterior fossa stroke CT limitationsStrategies to reduce false negativesLesson 10Key acute imaging signs: early ischemic changes, hyperdense vessel sign, territorial infarction patternsThis part covers key CT and MRI signs of acute ischaemia, including early parenchymal changes, hyperdense vessel sign, loss of gray–white differentiation, sulcal effacement, and characteristic territorial infarct patterns that map to specific vascular distributions.
Early ischemic CT signs and ASPECTS useHyperdense artery sign and variantsLoss of gray–white differentiation patternsTerritorial infarct patterns by vascular territoryPosterior circulation and lacunar stroke signs
