I read with great interest the editor’s choice in the Jan issue of AJNR “Blood-Brain Barrier Permeability Assessed by Perfusion CT Predicts Symptomatic Hemorrhagic Transformation and Malignant Edema in Acute Ischemic Stroke” by Hom, Dankbaar, Soares, and colleagues.  The article presented promising data for the combined use of clinical metrics and dynamic perfusion/permeability data to predict symptomatic HT and malignant edema.

However, I want to bring attention to the authors’ representative figure 1 (page 46).  The follow-up hemorrhage 23 hours later appears on this single slice to be petechial in nature, and not a space occupying hematoma as stated by the authors, and certainly not one that would be categorized as parenchymal hematoma type 2 (PH2) by ECASS criteria.  PH2 must be a space occupying hematoma of >30% of the infarct zone with substantial mass effect attributable to the hematoma.  Unless, this slice is presented only for illustration purposes, and the remainder of the follow-up scan does show more extensive hemorrhage, I believe the hemorrhage depicted here should be categorized as hemorrhagic infarction type 2 (HI2) by ECASS criteria.  The associated mass effect/midline shift is to be expected as edema from a rather large infarct.  This is an important issue because only parenchymal hematomas are relevant clinically, while hemorrhagic infarctions do not portend poor prognosis (and may even be epiphenomenal, reflecting revascularization).