title: Intramural hematoma detection by susceptibility-weighted imaging in intracranial vertebral artery dissection.
abstract: BACKGROUND
  The radiologic diagnosis of vertebral artery dissection (VAD) depends on characteristic intraluminal findings on angiography and intramural hematoma or a double-lumen sign on high-resolution vessel wall imaging. We aimed to evaluate the accuracy of intramural hematoma sign on susceptibility-weighted imaging (SWI) in VAD.
  
  
  METHODS
  We retrospectively analyzed SWI, phase map images and brain computed tomography (CT) of the consecutive patients who suffered an ischemic stroke in the vertebral artery territory from August 2010 to July 2012. We divided the patients into 2 groups: the VAD group and the nondissection group. VAD was diagnosed by conventional catheter angiographic findings (aneurysmal dilatation, pearl-and-string or tapered steno-occlusion) and pathognomonic findings such as intramural hematoma or a double-lumen sign on the source images of TOF-MRA, high-resolution T1-weighted MRI or high-resolution T2-weighted MRI. Intramural hematoma sign was considered positive if the patient had an eccentric or concentric hypointense signal lesion in the vertebral artery on SWI, a corresponding hyperintense signal on phase map and no evidence of calcification on the brain CT, suggesting blood products other than calcification. Two experienced neuroradiologists blinded to clinical information and angiographic findings were asked to judge for the presence of intramural hematoma sign on SWI. The accuracy of intramural hematoma sign on SWI was evaluated. Phase value, demographic and clinical data were compared between the VAD and the nondissection groups.
  
  
  RESULTS
  Thirty-nine patients were included: 10 in the VAD group and 29 in the non-dissection group. Among the VAD group cases, intramural hematoma sign on SWI was positive in 9 of the 10 VAD cases and in 1 out of the 29 cases in the nondissection group. The intramural hematoma sign on SWI was significantly associated with VAD (p < 0.001), and showed sensitivity of 90% and specificity of 96.6%. Mean phase values of intramural hematomas (n = 9) were all positive and those of calcified lesions (n = 13) were all negative (0.45 radian vs. -0.42 radian, p < 0.001).
  
  
  CONCLUSIONS
  The intramural hematoma sign on SWI was significantly associated with VAD and the phase map values were higher in intramural hematomas when compared with atherosclerotic calcifications.
authors.affiliation: Department of Neurology, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, South Korea.
authors.forename: Tae-Won
authors.initials: TW
authors.lastname: Kim
authors.forename: Hyun Seok
authors.initials: HS
authors.lastname: Choi
authors.forename: Jaseong
authors.initials: J
authors.lastname: Koo
authors.forename: So Lyung
authors.initials: SL
authors.lastname: Jung
authors.forename: Kook-Jin
authors.initials: KJ
authors.lastname: Ahn
authors.forename: Bum-Soo
authors.initials: BS
authors.lastname: Kim
authors.forename: Yong Sam
authors.initials: YS
authors.lastname: Shin
authors.forename: Kwang Soo
authors.initials: KS
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D002533:Cerebral Angiography / Q000379:methods; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006406:Hematoma / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D002537:Intracranial Arteriosclerosis / Q000175:diagnosis; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D012042:Registries; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D061205:Vascular Calcification / Q000175:diagnosis; D014711:Vertebral Artery / Q000000981:diagnostic imaging / Q000473:pathology*; D020217:Vertebral Artery Dissection / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology