title: Differentiating intraparenchymal hemorrhage from contrast extravasation on post-procedural noncontrast CT scan in acute ischemic stroke patients undergoing endovascular treatment.
abstract: BACKGROUND
  This study aimed to identify the imaging characteristics that can help differentiate intraparenchymal hemorrhage from benign contrast extravasation on post-procedural noncontrast CT scan in acute ischemic stroke patients after endovascular treatment.
  
  
  METHODS
  We reviewed the clinical and imaging records of all acute ischemic stroke patients who underwent endovascular treatment in two hospitals over a 3.5-year period. The immediate post-procedural CT scan was evaluated for the presence of hyperdense lesion(s). The average attenuation of the lesion(s) was measured. Intraparenchymal hemorrhage was defined as a persistent hyperdensity visualized on follow-up CT scan, 24 h or greater after the procedure.
  
  
  RESULTS
  Of the 135 patients studied, 74 (55%) patients had hyperdense lesion(s) on immediate post-procedural CT scan. Follow-up scans confirmed the diagnosis of intraparenchymal hemorrhage in 20 of these 74 patients. A receiver operating characteristic analysis showed that the average attenuation of the most hyperdense lesion can differentiate intraparenchymal hemorrhage from contrast extravasation with an area under the curve of 0.78 (p = 0.001). An average attenuation of <50 Hounsfield units (HU) in the most visually hyperattenuating hyperdense lesion had 100 % specificity and 56% sensitivity for identification of contrast extravasations. Petechial hyperdensity was seen in 46/54 (85%) patients with contrast extravasation versus 9/20 (45%) patients with intraparenchymal hemorrhage on the immediate post-procedural CT scan (p < 0.001).
  
  
  CONCLUSIONS
  An average attenuation <50 HU of the most hyperattenuating hyperdense parenchymal lesion on immediate post-procedural CT scan was very specific for differentiating contrast extravasation from intraparenchymal hemorrhage in acute ischemic stroke patients after endovascular treatment.
authors.affiliation: Zeenat Qureshi Stroke Institute, Dinnaken Office Building, 925 Delaware Street SE, Suite 300, Minneapolis, MN, 55414, USA.
authors.forename: Seyedmehdi
authors.initials: S
authors.lastname: Payabvash
authors.forename: Mushtaq H
authors.initials: MH
authors.lastname: Qureshi
authors.forename: Shayaan M
authors.initials: SM
authors.lastname: Khan
authors.forename: Mahnoor
authors.initials: M
authors.lastname: Khan
authors.forename: Shahram
authors.initials: S
authors.lastname: Majidi
authors.forename: Swaroop
authors.initials: S
authors.lastname: Pawar
authors.forename: Adnan I
authors.initials: AI
authors.lastname: Qureshi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000150:complications / Q000601:surgery*; D002543:Cerebral Hemorrhage / Q000000981:diagnostic imaging*; D003287:Contrast Media; D003937:Diagnosis, Differential; D057510:Endovascular Procedures; D005119:Extravasation of Diagnostic and Therapeutic Materials / Q000000981:diagnostic imaging*; D006801:Humans; D008875:Middle Aged; D059906:Neuroimaging; D011183:Postoperative Complications / Q000000981:diagnostic imaging*; D012189:Retrospective Studies; D020521:Stroke / Q000209:etiology / Q000601:surgery*; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D003287:Contrast Media