Introduction: FLAIR vascular hyperintensities (FVH), also known as “slow flow” signs, reflect arterial hemodynamic slowing downstream of stenosis or occlusion. In hyperacute ischemic stroke, FVH can precede parenchymal diffusion-weighted imaging (DWI) abnormalities and serve as an indirect marker of hypoperfusion. Their integration into the clinical-radiological assessment may influence thrombolysis decisions, particularly when perfusion imaging is unavailable. Methods: We conducted a prospective descriptive series of three hyperacute ischemic strokes managed within an MRI-first pathway in a tertiary center. Clinical data, imaging findings (FLAIR, DWI, T2*), and treatment details were recorded. FVH were qualitatively assessed for extent and distribution. The main outcome was early clinical improvement (NIHSS variation) and absence of hemorrhagic transformation on 24-hour MRI. Results: All patients presented with disabling deficits despite low-to-moderate NIHSS scores (4 - 10). Initial MRI performed within 2 hours of symptom onset showed prominent FVH without DWI lesions (n = 2) or with minimal changes (n = 1). No thrombus was detected on T2*. All received intravenous thrombolysis (alteplase 0.9 mg/kg) within 2 h 30 min. Follow-up MRI at 24 hours revealed no infarction or hemorrhagic conversion. Clinical improvement was significant in all cases (median NIHSS decrease: ？6 points), with resolution or marked reduction of deficits at discharge. Conclusion: In ultra-early ischemic stroke, FVH represent an operational marker of hypoperfusion that may guide thrombolysis, particularly when perfusion imaging is not accessible. The FVH-DWI mismatch can substitute for the perfusion-diffusion mismatch in identifying salvageable tissue. In resource-limited settings, especially in sub-Saharan Africa, recognizing FVH could expedite therapeutic decisions and optimize outcomes. Larger studies with standardized FVH quantification are needed to confirm their prognostic value.
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