Lesson 1Perfusion imaging interpretation: core vs penumbra, Tmax, CBF, CBV thresholds and pitfallsThis part details how to interpret CT and MR perfusion, telling core from penumbra using CBF, CBV, and Tmax maps, looking at common number thresholds, differences between machine makers, artefacts, and clinical traps that might mislead treatment choices in urgent cases.
Physiologic basis of core and penumbraTmax, CBF, and CBV map interpretationCommon numeric thresholds and caveatsArtifacts, motion, and truncation errorsChronic infarct and leukoaraiosis pitfallsLesson 2Guidelines and decision thresholds: major society recommendations for imaging selection and treatment windowsThis part sums up main guideline suggestions for acute stroke imaging, including time limits for IV thrombolysis and thrombectomy, imaging choices beyond standard times, and how to use decision thresholds in everyday practice in resource-limited settings like Zambia.
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 centres on short, strong communication with the stroke team, including standard words for thrombolysis and thrombectomy suitability, statements on uncertainty, suggested next imaging, and advice on monitoring and repeat scans to aid quick decisions.
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 describes MRI protocol setup for very early stroke, detailing DWI and ADC for core, FLAIR for start time guess, SWI for bleeding and clot, TOF/MRA for vessels, and perfusion MRI settings suited to time-critical choices in emergency care.
Optimizing 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 report for stroke emergencies, stressing clear details of bleeding, ischemic core and penumbra, blockage spot, side and vessel area, and direct, time-urgent suggestions for thrombolysis, thrombectomy, and follow-up imaging.
Standardized report headings and sequenceDocumenting hemorrhage 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 types, contrast timing, and perfusion area to balance speed, radiation, and diagnosis accuracy in Zambian clinics.
Noncontrast CT slice thickness and kernelsCTA acquisition timing and contrast bolusCT perfusion coverage and slab selectionRadiation dose, ASIR, and artifact reductionMotion management and patient positioningLesson 7Selecting emergency imaging: noncontrast CT, CT angiography, CT perfusion and MRI alternativesThis part reviews choosing emergency imaging paths, comparing noncontrast CT, CTA, CT perfusion, and MRI based on time from start, patient steadiness, no-go factors, and local tools to make efficient, proof-based plans for stroke care.
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 step-by-step check of vessel blockage, including spotting blockage site, clot length, side vessel flow, and clot burden scores on CTA and MRA, and how these affect thrombectomy choices and outlook in patients.
Identifying proximal versus distal occlusionsMeasuring thrombus length on CTACollateral grading systems and scoringClot burden score and prognosisImaging predictors of recanalizationLesson 9False negatives and mimics: seizure, migraine, hypoglycemia, posterior fossa limitations and strategies to reduce errorsThis part tackles false misses and stroke look-alikes, like fits, headaches, low sugar, body function issues, and back brain strokes, and shows imaging plans and changes to cut diagnosis mistakes in very early settings.
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 main CT and MRI signs of early lack of blood, including early tissue changes, dense vessel sign, loss of grey-white difference, groove flattening, and typical area infarct shapes that match certain vessel paths.
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
