Introduction: Ischemic brain lesions might present with unexpected increased signal intensity at MR angiography within the ischemic lesion and secondary parenchymal changes in regions distal to the ischemia itself. We retrospectively investigated the rate and time course of vascular and parenchymal changes in children with isolated middle cerebral artery (MCA) stroke.
Methods: Twelve children (mean age at stroke onset 4.8 years, range 0.8-15 years, six females, seven right MCA strokes) suffering from a first ever acute isolated MCA stroke had repeated MR scans (mean scan number, 3.5; range 2-6; mean follow-up, 11 months; range 0.5-24 months).
Results: Ipsilaterally to MCA stroke, we recorded increased vessel signal at MR angiography during first to fourth day in 4/7 children (all had MCA recanalization), corticospinal tract cytotoxic-like edema during second day to second month in 7/11 (three children with globus pallidum ischemia had concomitant substantia nigra changes during second to third week), corticospinal tract T2 abnormalities from fifth day onwards in 9/12, focal thalamic cytotoxic-like edema during fifth day to first month in 5/8, focal thalamic T2 hyperintensity during sixth day to third week in 2/4, and faint T2 hypointensity from second month in 7/10 children.
Conclusion: Vascular and secondary parenchymal changes, likely due to luxury perfusion, Wallerian, retrograde, or trans-synaptic degeneration, are common in pediatric MCA stroke population. They might mimic new ischemic lesions or suggest conditions different from stroke leading to diagnostic pitfalls and inappropriate treatment.