Challenges in Differentiating Stroke Mimics from Acute Ischemic Stroke: Case Analysis and Imaging-Based Diagnostic Approaches

Objectives*
Stroke mimics (SM) are clinical conditions that resemble cerebral strokes but arise from different etiologies.
Ischemic strokes represent 80% of cases, while hemorrhagic strokes account for 20%. SM constitutes 9-31% of
suspected stroke cases and 2.8-17% of cases treated with intravenous thrombolysis (IV-tPA). Common causes of
SM include seizures, particularly Todd’s paralysis (17-21%), sepsis (13-17%), toxic or metabolic disturbances (11-
13%), space-occupying lesions (9-15%), and syncope (9%). Advanced imaging techniques, including non-contrast
CT, CT-angiography, and MRI, are essential for distinguishing ischemic strokes from stroke mimics.
Results
In a multicenter observational cohort study by Zinkstok, involving 5581 patients treated with IVT for acute
ischemic stroke, stroke mimics occurred at a frequency of 1.8%, predominantly affecting younger, more often
female patients with fewer risk factors except for smoking and prior stroke or TIA, and had a lower rate of
symptomatic intracranial hemorrhage (1.0%) compared to ischemic strokes (7.9%).
At our clinic, we have encountered various cases of SM initially suspected as ischemic or hemorrhagic strokes.
Seizures account for approximately 20% of these mimics, with most being brief, having a median duration
of 3-minutes. Diffusion-weighted imaging-(DWI) with apparent diffusion coefficient (ADC) sequences aids in
differentiating between remote strokes with seizures and recent ischemic strokes.
For example, a 45-year-old female with a history of alcohol abuse and focal epilepsy presented in severe con-
dition after a generalized tonic-clonic seizure. Radiological findings revealed extensive cytotoxic edema in the
left hemisphere and a smaller lesion in the right cerebellum, leading to a diagnosis of status epilepticus. Other
notable cases include a patient with hypoglycemia, a 74-year-old female diagnosed with anaplastic oligoden-
droglioma (Grade-3), and a 49-year-old patient presenting with Wernicke encephalopathy.
Conclusions
The challenges of stroke mimics include diagnostic delays and inappropriate treatments. Efficient imaging
workflows and radiologist awareness of stroke mimics are essential for ensuring accurate diagnoses and timely
interventions.