1. Role of a novel material decomposition algorithm in detection of acute infarction
M F Mohammed, MBBS CIIP, Vancouver, BC; F Khosa, FFR(RCSI), FRCPC; D J Ferguson, MBBCh, FRCR; R S Zakzouk, MD; O Marais, BEng; T O'Connell, MD, Meng; et al.

2. Introduction Nonenhanced CT: Exclude hemorrhage
Detect "early signs" of infarction

3. Introduction Nonenhanced CT:
Prevalence of all early infarction signs: 61%
Interobserver agreement: 0.14 – 0.78
Sensitivity: 66%
Specificity: 87%
Wardlaw JM, Mielke O. Early Signs of Brain Infarction at CT: Observer Reliability and Outcome after Thrombolytic Treatment—Systematic Review. Radiology. Radiological Society of North America. 2005;235:444–453.

4. Introduction
MRI: Gold standard
Time
Access
Contraindications

5. Introduction
We introduce a novel material decomposition algorithm to improve detection of infarcts on Noncontrast Dual Energy CT

6. Materials & Methods Retrospective IRB-approved study
40 consecutive patients labelled as “Stroke Code Activations”
January 2016– April 2016
< 4 hours since onset of symptoms

7. Materials & Methods Noncontrast DECT CTA Arch – Vertex
Follow-up CT after 24 hours served as reference standard for infarct

8. Materials & Methods Dual-Source, Dual Energy Scan Tube A: 90 kV
Tube B: 150 kV with Sn prefiltration

9. Materials & Methods Datasets post-processed on syngo.via platform
3 material decomposition performed with base materials of air, water and iodine
Parameters adjusted to subtract Gray Matter from White Matter
Produces altered “VNC” images that accentuate cytotoxic edema
8 mm averaged axial images are reconstructed with color “Brain Edema” map

10. Materials & Methods
Reviewed independently by 2 fellowship trained Neuroradiologists
Blinded to all relevant clinical information and patient outcomes except for side of symptoms
ASPECT scores were assigned to the True Noncontrast CT and “Brain Edema” reconstructions
Each study was compared independently with ASPECT score on 24 hour f/u

15. Results
28 out of 40 patients had an acute infarct (ASPECT < 10 at 24 hours)

16. Results Results TNC Brain Edema Sensitivity 80% 93.3% Specificity
72.7%
100%
PPV
NPV
91.7%

17. Results
“Brain Edema” images resulted in a change of ASPECT score by an average of 1.95 points
“Brain Edema” images also correlated excellently with 24 hour follow up CT; r = (p < )
Very good inter-observer agreement; Kappa = 0.85 (95% CI: 0.7 – 1)

21. Conclusions
“Brain Edema” images improves sensitivity and specificity in detecting acute infarcts
“Brain Edema” images provide a more accurate ASPECT score when compared TNC images
Provides an alternative in patients that cannot receive iodinated contrast or when MRI access is limited

22. Limitations
No MRI follow-up
Relatively small cohort

23. Questions?

24. Thank You