1. Certainty of Stroke Diagnosis: Incremental Benefit with CT Perfusion over NC-CT & CTA Richard I. Aviv, Julia Hopyan, Anthony Ciarallo, et al (including Ting-Yim Lee) Radiology 2010;255:142-153

2. stroke <1 hr - R hemisphere

3. ICA, MCA, ACA termination occlusion L R

4. stroke <1 hr - CTA source images (SI) Aviv et al Clin Radiol. 2007;62:447

5. CT-Perfusion matched defects: no penumbra! no brain at risk to salvage! blood flow rCBF blood volume CBV mean transit time MTT Murphy et al. Stroke 2006. 37:1771 Aviv et al. AJNR 2007; 28:1975 Murphy et al. Radiology. 2008 247:818 matched CBV = infarction

6. CBV for infarction identification CT perfusion match or mismatch Murphy, Fox, Lee et al, Stroke 2006 37:1771

7. CT stroke protocol - 4 (64 +) slice CT CT stroke protocol - 4 (64 +) slice CT NON CONTRAST CT~ 20 sec NON CONTRAST CT~ 20 sec CTA NECK & HEAD~ 20 sec MIP-MRPs (2D) - coronal, sagittal, rotating obliques (secs) CTA NECK & HEAD~ 20 sec MIP-MRPs (2D) - coronal, sagittal, rotating obliques (secs) a) MIP MPRs done immediately by techs * CT-P 2cm (8cm) BASAL GANGLIA & VENTS~ 40 sec CT-P 2cm (8cm) BASAL GANGLIA & VENTS~ 40 sec a) rCBF (cerebral blood flow ml/100 g brain/minute) b) CBV (blood volume) c) MTT (transit time) d) flow maps done immediately by techs POST CONTRAST CT~ 20 sec POST CONTRAST CT~ 20 sec TOTAL SCANNING ~100 sec NOT MUCH MORE TIME THAN SIMPLE NCCT ALONE * no time waste time for rendering; MPRs off operating console by techs * main advantage of CT over MR stroke protocol is time

8. acute stroke – large mismatch CBV

9. post contrast CT shows shows grey matter grey matter to white matter: to white matter: shows CBV shows CBV

10. CTA SI shows CBF CTA SI: Volume or Flow Weighted? Sarma et al; AJNR In Press

11. matched opercular defect = infarction CBF CBV MTT

12. sample MPR reformats no larger cerebral vessel occlusion

13. right MCA branch occlusion contrast disappears with scrolling

14. NC-CT PC-CT slab CTA-SI images show loss of grey matter density on NCCT, more conspicuous on PCCT, and well seen on SI

15. Certainty of Stroke Diagnosis: Incremental Benefit with CT Perfusion over NC-CT & CTA Richard I. Aviv, Julia Hopyan, Anthony Ciarallo, et al (including Ting-Yim Lee) Radiology 2010;255:142-153

16. purpose systematically evaluate diagnostic benefits and inter- & intra-observer reliability of incremental CT protocol confirm clinically suspected stroke - combined imaging & clinical data as reference standard

17. materials and methods IRB and patient consent IRB and patient consent 191 consecutive patients ≤3hr stroke with CTP and MRI <30 days 191 consecutive patients ≤3hr stroke with CTP and MRI <30 days 4 readers 4 readers 2 neurology fellows (1 st year of stroke fellowship) 2 neurology fellows (1 st year of stroke fellowship) 2 neuroradiologists (6/12 post fellowship) 2 neuroradiologists (6/12 post fellowship) incremental review 1 month apart: incremental review 1 month apart: NCCT NCCT NCCT and CTA-SI NCCT and CTA-SI NCCT, CTA-SI, and CTP NCCT, CTA-SI, and CTP anonymized data, no clinical data, K-PACS anonymized data, no clinical data, K-PACS

18. materials and methods 5-point scale for confidence of ischemia/ infarct presence 5-point scale for confidence of ischemia/ infarct presence 1 stroke definitely absent 2 stroke probably absent 3 equivocal 4 stroke probably present 5 stroke definitely present

19. materials and methods reference standard reference standard experienced neurologist (5 years) experienced neurologist (5 years) review clinical and imaging (CTP/MRI) data review clinical and imaging (CTP/MRI) data TIA considered positive TIA considered positive

20. statistical analysis logistic regression analysis compare real vs observed diagnosis, adjusting for confidence logistic regression analysis compare real vs observed diagnosis, adjusting for confidence Akaike information criterion (AIC) and ROC compare performance for each read generalized estimating equation to correlate data from 4 readers, adjusting for confidence generalized linear model, binomial distribution

21. results 191 patients (55% ♂); 67±16yrs 191 patients (55% ♂); 67±16yrs mean NIHSS and ASPECTS 9 mean NIHSS and ASPECTS 9 time to onset 117±59 mins time to onset 117±59 mins median MRI F/U 3 (0-29) days median MRI F/U 3 (0-29) days final diagnosis final diagnosis stroke 123 (64%) stroke 123 (64%) large vessel (70%) large vessel (70%) small vessel (30%) small vessel (30%) TIA 36 (18%) TIA 36 (18%) stroke mimic 32 (17%) stroke mimic 32 (17%)

22. results observed diagnosis significantly related to real diagnosis for all 3 protocols, after adjusting confidence (LinRegr and GLM) observed diagnosis significantly related to real diagnosis for all 3 protocols, after adjusting confidence (LinRegr and GLM) confidence correct diagnosis: 3.3 NCCT 3.3 NCCT 6.4 NCCT+CTA-SI 6.4 NCCT+CTA-SI 13.3 NCCT+CTA-SI+CTP 13.3 NCCT+CTA-SI+CTP

23. confidence distribution each sequence confidence score NCCT N (%) NCCT CTA N (%) NCCTCTACTP N (%) 2 or 4 (probable) 454 (59) 401 (52) 208 (27) 3 (equivocal) 180 (24) 76 (10) 34 (4) 1 or 5 (certain) 130 (17) 287(38) 522 (68) fewer equivocal/probable responses Increased certain diagnoses with CTP usage

24. results ROC: confidence score of ≥4 optimal ROC: confidence score of ≥4 optimal

25. results ROC AUC ROC AUC 0.67 NCCT 0.67 NCCT 0.72 NCCT+CTA-SI 0.72 NCCT+CTA-SI 0.81 NCCT+CTA-SI+CTP 0.81 NCCT+CTA-SI+CTP CTP CTA NCCT

26. results Fair Substantial Moderate

27. NC-CT CTA-SICBF CBV MTTDWI

28. NC-CT CTA-SI CBF CBV MTTDWI

29. NC-CT CTA-SI CBF CBV MTTDWI

30. NC-CT CTA-SICBF CBVMTT DWI

31. discussion & conclusions CTP added to NCCT & CTA improves stroke detection amongst inexperienced readers CTP added to NCCT & CTA improves stroke detection amongst inexperienced readers 13x NCCT or 6x CTA 13x NCCT or 6x CTA less experienced readers simulate real world experience less experienced readers simulate real world experience real advance: CT infarct diagnosis easy! real advance: CT infarct diagnosis easy! improved confidence of diagnosis improved confidence of diagnosis reliable inter and intra-observer agreement reliable inter and intra-observer agreement neuroradiologists not content with poor performance with NCCT alone to show infarct neuroradiologists not content with poor performance with NCCT alone to show infarct