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Objectives: There are different definitions of transient ischemic
attacks (TIA) in the literature. To date, many authors prefer to displace
the old time-based definition (symptoms lasting less than 24 h)
by a tissue-based definition, also requiring DWI negative magnetic
resonance imaging (MRI) to diagnose TIA. Our study aimed to
investigate whether a tissue-based TIA definition has an impact on
median lesion volumes of a stroke cohort.
Methods: Included were patients with the final diagnosis of firstever
ischemic stroke or TIA. Main exclusion criteria were intracranial
hemorrhage, epilepsy, intracranial tumor and final diagnosis other
than stroke or TIA. All patients received immediate CT imaging and
early follow-up imaging by CT or MRI.
Results: We screened 524 consecutive patients and included 408 in
final analysis. Initial imaging modality was MRI in 17 (4 %) and CT in
all other patients. A total of 330 (81 %) patients received MRI either
initially or during early follow-up. After MRI, a total of 70 (17 %)
patients fulfilled tissue-based criteria of TIA. 9 (2.2 %) patients with
the clinical diagnosis of stroke (symptoms lasting more than 24 h) had
DWI-negative MRI. Median lesion volume of all strokes measured by
CT or MRI was 3.36 ml (IQR 0.65–19.95). In patients examined with
CT only, median lesion volume was higher (14.8 ml; IQR 0–72.63).
Conclusion: Compared to data in the literature referring to a timebased
TIA definition, where median stroke volumes tend to range
between 15 and 20 ml, median lesion volumes are significantly
smaller in this large stroke cohort. We conclude that appliance of a
tissue-based TIA definition has a major impact on the median lesion
size in a stroke cohort. This might be due to the mostly small DWI
lesions found in a significant proportion of suspected TIA patients.