Abstract 3095: CT Perfusion Deficits Are Present in Acute Transient Ischemic Attack Patients Utilizing 320 Detector Row Whole Brain CT Perfusion Studies and are Associated with ABCD2 score
Authors: Mustafa Ghulam , Masud M. Waqas , Gunukula Sameer , Mokin Maxim , Kandel Amit , Kass-Hout Omar , Kass-Hout Tareq , Mehta Bijal K 
Published: March 2022

INTRODUCTION:
Transient ischemic attacks (TIA) are generally milder forms of cerebral ischemia, without end organ damage. However, infarction or permanent ischemia is seen in TIA. The use of perfusion techniques such as cerebral blood volume (CBV), time to peak (TTP), mean transit time (MTT), and cerebral blood flow (CBF) provide real time data about ischemia. Whole brain CT perfusion studies are limited to only a few dozen stroke centers that have high detector row CT scanners.

OBJECTIVE:
To demonstrate that TIA's have significant numbers of perfusion deficits using whole brain 320 detector row CT perfusion, and to show an association between the ABCD2 score and the presence of perfusion deficit using whole brain perfusion.

METHODS:
We retrospectively reviewed all TIA patients for CT perfusion deficits at our "Gold+, JACHO" stroke center from 2008 to 2010. Exclusion criteria included patients who did not receive a CT scan during the study period and all ischemic or hemorrhagic stroke patients as confirmed by MRI or CT. Patients that had an ABCD2 score at time of imaging/admission were included in the study. Perfusion imaging was reviewed at admission by a neurologist and a radiologist; and reports stated if a perfusion deficit was noted, type (CBV, TTP, MTT, CBF) and vascular territory.

RESULTS:
Of 368 TIA patients, 66 patients had perfusion deficits. The largest group of patients had MCA territory involved at 52 of 66 (78.79%). The second largest of the groups was 11 (16.67%) with PCA territory or posterior fossa involved. Lastly 3 patients had ACA territory involvement (4.55%).The most common perfusion abnormality was increased TTP with 48 patients(72.73%). Increased MTT was noted in 17 patients (25.76%) and change in CBF in 14 patients (21.21%); and 6 patients with decreased CBV (9.09%). Using logistic regression, the components of ABCD2 score (age, blood pressure, character of symptoms, history of diabetes, and duration of symptoms) were reviewed in relation to the presence of perfusion deficit. Increased age greater than 65, hypertension (both systolic and diastolic) at the time of the TIA, patients that had weakness rather than only speech abnormalities, and duration of symptoms longer than an hour were all more likely to have a perfusion deficit. However, a history of diabetes or hypertension was not associated with a higher likelihood of perfusion deficit.

DISCUSSION:
The ABCD2 score can determine whether TIA patients are admitted for other diagnostic tests. Attention to CT perfusion in association with ABCD2 scores may better address potential risk factors of secondary stroke.

CONCLUSION:
There are perfusion deficits in TIA patients using 320 detector row whole brain perfusion protocol. Also, worsening criteria in each of the ABCD2 score modalities, except diabetes, is associated with a higher likelihood of a perfusion deficit.