Introduction/purpose:
A significant complication in the intervention of acute ischemic stroke is hemorrhagic transformation (HT). It has been postulated that perfusion permeability imaging showing increased blood brain barrier permeability can be used to predict hemorrhagic transformation and possibly alter therapies.
Materials and Methods:
We retrospectively reviewed 1040 sequential CT perfusion scans with permeability surface area product maps calculated using the Patlak model for all patients that exhibited stroke like symptoms between October 2011 and November 2012. The size of the permeability surface product was ranked on a qualitative three-part scale of small, moderate and large permeability changes. A change smaller than 25% of the image was considered a small result. A moderate result is a permeability change that is approximately 25% of the image. A large permeability change exceeds 25% of the image. Follow up non-contrast CT images (>24 hours but <15 days after initial perfusion imaging) were used to determine if HT had occurred in the cases where an increase in permeability surface product was observed.
Results:
There was a positive increase in permeability maps in 142 of the 1040 cases. The size of the permeability change was moderate to large in 101 of the positive cases (71%). Hemorrhagic transformation was observed in 12 patients that showed an increase in permeability surface product (8.4%). Of the cases that resulted in HT, nine (75%) resulted in an HI1 and HI2 subtypes. There were three (25%) of the more severe parenchymal hemorrhages (PH1, PH2) observed. Out of the 12 positive hemorrhagic transformations four (33%) were treated with iv-TPA and two (17%) received endovascular thrombectomies, while six (50%) did not receive TPA or endovascular intervention. Of the major parenchymal hemorrhages (PH1/2) two occurred after iv-TPA treatment of the stroke, with the other arising after endovascular thrombectomy. No difference was found in the size or degree of the permeability changes and the incidence of HT.
Conclusions:
Elevated permeability on CT perfusion imaging had no relevant predictive value for hemorrhagic transformation in acute ischemic stroke at our institution.
Clinical application value of brain CT perfusion imaging in the treatment of acute ischemic stroke thrombolytic therapy