title: Differentiation of hemorrhage from iodinated contrast in different intracranial compartments using dual-energy head CT.
abstract: OBJECTIVE
  Identification of ICH, particularly after ischemic stroke therapy, is important for guiding subsequent antithrombotic management and is often confounded by contrast staining or extravasations within intracerebral or extra-axial compartments. This study evaluates the accuracy of DECT in distinguishing ICH from iodinated contrast in patients who received contrast via IA or IV delivery.
  
  
  METHODS
  Forty patients who had received IA or IV contrast were evaluated using a DECT scanner at 80kV and 140kV to distinguish hyperdensities secondary to contrast staining or extravasation from those representing ICH. A 3-material decomposition algorithm was used to obtain virtual noncontrast images and iodine overlay images. Sensitivity, specificity, and accuracy of DECT in prospectively distinguishing intracranial contrast from hemorrhage within parenchymal, subarachnoid, extra-axial, intraventricular, and intra-arterial compartments were computed using routine clinical follow-up imaging as the standard of reference.
  
  
  RESULTS
  A total of 148 foci of intracranial hyperattenuation were identified. Of these, 142 were correctly classified for the presence of hemorrhage by DECT. The sensitivity, specificity, and accuracy for identifying hemorrhage, depending on the compartment being considered, were 100%, 84.4%-100%, and 87.2%-100%, respectively. The only instances where DECT failed to correctly identify the source of hyperattenuation was in the presence of diffuse parenchymal calcification (n = 5) and a metallic streak artifact (n = 1).
  
  
  CONCLUSIONS
  After IA and/or IV contrast administration, DECT can accurately differentiate all types of ICH from iodinated contrast without employing any additional radiation.
authors.affiliation: Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA. cmphan@partners.org
authors.forename: C M
authors.initials: CM
authors.lastname: Phan
authors.forename: A J
authors.initials: AJ
authors.lastname: Yoo
authors.forename: J A
authors.initials: JA
authors.lastname: Hirsch
authors.forename: R G
authors.initials: RG
authors.lastname: Nogueira
authors.forename: R
authors.initials: R
authors.lastname: Gupta
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D001921:Brain / Q000000981:diagnostic imaging*; D002533:Cerebral Angiography / Q000379:methods*; D002543:Cerebral Hemorrhage / Q000000981:diagnostic imaging*; D003287:Contrast Media / Q000008:administration & dosage; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007269:Injections, Intra-Arterial; D007275:Injections, Intravenous; D007455:Iodine / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D015900:Radiography, Dual-Energy Scanned Projection / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007455:Iodine