title: Evaluation of dual-energy CT for differentiating intracerebral hemorrhage from iodinated contrast material staining.
abstract: OBJECTIVE
  To evaluate the efficacy of dual-energy computed tomography (CT) in the differentiation of intracerebral hemorrhage (ICH) from iodinated contrast material in patients who received contrast material via intraarterial or intravenous delivery.
  
  
  METHODS
  This retrospective study was approved by the local institutional review board, which waived the informed consent requirement for the analysis. Sixteen patients with acute stroke and two with head trauma who had undergone intraarterial or intravenous administration of iodinated contrast material were evaluated by using dual-energy CT to differentiate areas of hyperattenuation secondary to contrast material staining from those representing ICH. A dual-energy CT scanner was used for imaging at 80 and 140 kV, and a three-material decomposition algorithm was used to obtain virtual unenhanced images and iodine overlay images. The sensitivity, specificity, and accuracy of dual-energy CT in the prospective differentiation of intraparenchymal contrast material from hemorrhage were obtained. Follow-up images were used as the standard of reference.
  
  
  RESULTS
  There were 28 intraparenchymal areas of hyperattenuation classified at dual-energy CT as iodinated contrast material staining (n = 20, 71%), hemorrhage (n = 5, 18%), or both (n = 3, 11%). Two of the three areas of hyperattenuation seen on both virtual unenhanced and iodine overlay images were related to mineralization. The sensitivity, specificity, and accuracy of dual-energy CT in the identification of hemorrhage were 100% (six of six areas), 91% (20 of 22 areas), and 93% (26 of 28 areas), respectively.
  
  
  CONCLUSIONS
  Dual-energy CT can help differentiate ICH from iodinated contrast material staining with high sensitivity and specificity in patients who have recently received intraarterial or intravenous iodinated contrast material.
authors.affiliation: Department of Radiology, Massachusetts General Hospital, Neuroradiology GRB-273A, Boston, MA 02114, USA.
authors.forename: Rajiv
authors.initials: R
authors.lastname: Gupta
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Phan
authors.forename: Christianne
authors.initials: C
authors.lastname: Leidecker
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Brady
authors.forename: Joshua A
authors.initials: JA
authors.lastname: Hirsch
authors.forename: Raul G
authors.initials: RG
authors.lastname: Nogueira
authors.forename: Albert J
authors.initials: AJ
authors.lastname: Yoo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002543:Cerebral Hemorrhage / Q000000981:diagnostic imaging* / Q000209:etiology; D003287:Contrast Media / Q000008:administration & dosage*; D006259:Craniocerebral Trauma / Q000150:complications; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007455:Iodine / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D011857:Radiographic Image Interpretation, Computer-Assisted; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D020521:Stroke / Q000150:complications; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007455:Iodine