title: Prospective evaluation of suspected stenoocclusive disease of the intracranial artery: combined MR angiography and CT angiography compared with digital subtraction angiography.
abstract: OBJECTIVE
  MR angiography is primarily and increasingly used to assess intracranial arterial stenoocclusion. However, MR angiography can cause overestimation of stenosis. Although CT angiography is accurate, it has limitations. Our purpose was to determine whether the accuracy of combined MR angiography and CT angiography is equal to that of digital subtraction angiography (DSA) in measuring stenosis and detecting major intracranial arterial occlusion.
  
  
  METHODS
  CT angiography and intraarterial DSA were prospectively performed in 18 patients with suspected intracranial stenoocclusive disease, as revealed with MR angiography. Before DSA, two reviewers independently assessed MR intracranial angiograms. Subsequently, they assessed CT angiograms with MR angiograms. Results were compared with DSA results. The degree of stenoocclusion was categorized; stenosis of 50% or more indicated stenoocclusive disease. After the blinded study, two radiologists retrospectively reviewed the angiographic findings.
  
  
  RESULTS
  Stenoocclusive disease was identified in 18 of 198 intracranial arteries at DSA. MR angiography had a sensitivity of 92%, a specificity of 91%, and an accuracy of 91% for the identification of stenosis of 50% or more; the addition of CT angiography yielded values of 100%, 99%, and 99%, respectively. Stenotic grades with combined CT angiography and MR angiography agreed with those of DSA in 98% of cases. In the retrospective study, CT angiography did not always correctly delineate arterial lumina with circumferential calcification and cavernous portions of the internal carotid artery.
  
  
  CONCLUSIONS
  In this investigation, the evaluation of suspected stenoocclusive diseases in major intracranial arteries, the accuracy of combined MR angiography and CT angiography is equal to that of DSA in most cases.
authors.affiliation: Department of Radiology, Amakusa Medical Center, 854-1 Kameba, Hondo, Kumamoto 863-0046, Japan.
authors.forename: Toshinori
authors.initials: T
authors.lastname: Hirai
authors.forename: Yukunori
authors.initials: Y
authors.lastname: Korogi
authors.forename: Ken
authors.initials: K
authors.lastname: Ono
authors.forename: Masafumi
authors.initials: M
authors.lastname: Nagano
authors.forename: Kousei
authors.initials: K
authors.lastname: Maruoka
authors.forename: Shozaburo
authors.initials: S
authors.lastname: Uemura
authors.forename: Mutsumasa
authors.initials: M
authors.lastname: Takahashi
mesh_terms: D000328:Adult; D000368:Aged; D015901:Angiography, Digital Subtraction; D002343:Carotid Artery, Internal / Q000473:pathology; D016893:Carotid Stenosis / Q000175:diagnosis*; D002533:Cerebral Angiography; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D002537:Intracranial Arteriosclerosis / Q000175:diagnosis*; D002546:Ischemic Attack, Transient / Q000175:diagnosis; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D014715:Vertebrobasilar Insufficiency / Q000175:diagnosis*