Abstract Details

Title Comparison of Two CTP Thresholds with MRI DWI Sequence in Diagnosing Acute Ischemic Stroke

Topic Cerebrovascular Disease and Interventional Neurology

Presentation(s) P6 - Poster Session 6 (11:45 AM-12:45 PM)

Poster/Presentation
Number 14-009

Objective 1. Comparison of conventional CT perfusion (CTP) threshold (CBF <30% and Tmax > 6 seconds) and modified CTP threshold (CBF <38%, and Tmax > 4 seconds) with diffusion weighted imaging (DWI) positive strokes on MRI for detection of acute ischemic stroke.
2. Evaluate their sensitivity and specificity in detecting stroke using MRI DWI positivity as the gold standard.

Background Common parameters used in CTP scans have been CBF and Tmax. The thresholds traditionally used for the CTP parameters have been CBF <30% and Tmax >6 seconds. Setting the threshold at CBF <38% and Tmax >4 seconds also detected acute ischemic strokes, but this has not been validated in the literature.

Design/Methods IRB waiver was obtained. 76 patients who underwent CT perfusion scan and MRI brain for acute stroke evaluation during a seven month period in a teaching hospital were screened. SPSS statistical software was used. Sensitivity and specificity was calculated. Cohen’s kappa analysis was done among the two thresholds.

Results Considering DWI on MRI for diagnosis of acute stroke as the gold standard, conventional CTP threshold had a lower sensitivity (54%) and higher specificity (85%) while modified CTP threshold had a higher sensitivity (96%), but lower specificity (23%).

Cohen's κ was calculated to determine if there was agreement among the diagnoses of stroke using modified and conventional CTP thresholds. There was poor agreement between the two judgments, κ = 0.142 (p=0.045).

Conclusions The modified CTP threshold proposed has a higher sensitivity but a lower specificity to detect acute ischemic stroke when compared to the conventional criteria.

Authors/Disclosures
Basil V. Peechakara, MD PRESENTER	Dr. Peechakara has nothing to disclose.
Thirukan R. Swaminathan, MBBS, PhD, FAAN (Neuro Team One)	Dr. Swaminathan has nothing to disclose.
Taylor Graham, MD	Dr. Graham has nothing to disclose.
Nathan Kumar, MD (.)	Dr. Kumar has nothing to disclose.
Maen Saleh, MD (Garden City Hospital)	Dr. Saleh has nothing to disclose.
Gustavo E. Faria Mendez, MD (Garden City Hospital)	Dr. Faria Mendez has nothing to disclose.
Ismail Rahal, DO (Garden City Hospital)	Dr. Rahal has nothing to disclose.
Irenne Maliakkal, MD (GARDEN CITY HOSPITAL)	Ms. Maliakkal has nothing to disclose.
Kashiff Ariff, MD	Dr. Ariff has nothing to disclose.
Nathan George	Mr. George has nothing to disclose.
Ayaz M. Khawaja, MD	Dr. Khawaja has nothing to disclose.
Alexander Tobar, DO	Dr. Tobar has nothing to disclose.
Pratik D. Bhattacharya, MD, MPH (International Medical Clinic)	Dr. Bhattacharya has a non-compensated relationship as a Research Advisor with Defeat MSA Alliance 501 (c) (3) that is relevant to AAN interests or activities.
Ramesh Madhavan, MD, FAAN (International Medical Clinic)	Dr. Madhavan has received stock or an ownership interest from TiaTech USA and TiaTech India. Dr. Madhavan has received intellectual property interests from a discovery or technology relating to health care.

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