SM account for up to 25% of admissions with stroke suspicion; moreover, it is believed that the number of admissions will increase over the next decades. Recent studies show CTP alterations in some SM, especially in seizures.

The aim of this study is to analyse possible clinical predictors of computed tomography perfusion (CTP) alterations in stroke mimics (SM) attended as stroke-code. 

We conducted a retrospective study including a series of SM attended as stroke-code (up to 24 hours of neurological signs or symptoms) by neurologists at a stroke center, between January 2017 and March 2018. All of them underwent multimodal-CT study including baseline computed tomography (CT), CT-angiography and CTP as part of our stroke-code protocol. We registered clinical variables, diagnosis, CTP alteration patterns and type of map affected: time to peak (TTP), cerebral blood flow (CBF) and cerebral blood volume (CBV).

772 patients were attended as stroke-code, 117 (15,15%) were SM.  Mean age (64±17.7 years), women (59%), NIHSS median 2 (1-5 QR). CTP alterations were detected in 31 (26,5%) of SM, more than half of them had a final diagnose of seizure or status epilepticus (67,74%). The most commonly altered CTP map was TTP (96,8%) and the most frequent pattern of alteration was unilateral (90,3%), in diffuse hemispheric (38,7%) or focal non-vascular territory (41,93%). In a multivariate model two factors were significantly associated with the altered CTP, the first one was age (odds ratio (OR) at the age of 65 1,036; 95% CI:1,005-1,069); OR every 5 years 1,259 (IC95%:1,087-1,458) and presence of aphasia (any type) OR 3,800 (95% CI:1,404-10,287).

Our results show that older age and aphasia are risk factors associated to CTP changes in our series of SM. These findings may help decide which patients attended as stroke-code might have larger benefit from CTP for SM diagnosis.