title: Parenchymal hyperdensity on computed tomography after intra-arterial reperfusion therapy for acute middle cerebral artery occlusion: incidence and clinical significance.
abstract: OBJECTIVE
  The purpose of the present study was to assess the incidence and clinical significance of the intraparenchymal hyperdense areas on the posttherapeutic CT scan just after intra-arterial reperfusion therapy.
  
  
  METHODS
  Seventy-seven patients with acute middle cerebral artery occlusion were studied prospectively with post-therapeutic CT. Hyperdense areas were classified into three groups: those in the lentiform nucleus, insular cortex and cerebral cortex. We investigated the incidence of hyperdense areas and hemorrhagic transformations and assessed whether location of hyperdense areas may play a role in the incidence of hemorrhagic transformations. We also evaluated correlation between early CT signs and hyperdense areas.
  
  
  RESULTS
  Forty-five hyperdense areas were seen in 37 of the 77 patients (48.1%): 19 of the 45 (42.2%) were confirmed to be hematomas themselves, 6 (13.4%) showed later conversion to petechial hemorrhages, and 20 (44.4%) showed rapid disappearance without hemorrhagic transformations. Eleven of the 37 patients (29.7%) had neurological worsening due to massive hematoma (symptomatic hemorrhage), whereas none of the 40 patients without hyperdense areas had symptomatic hemorrhage. The incidence of hemorrhage among hyperdense areas was significantly lower in the insular cortex than in the other 2 regions (P<0.01). On the other hand, hyperdense areas in the lentiform nucleus had a significantly higher incidence of neurological worsening (P<0.05). There was a significant correlation between early CT signs and hyperdense areas (P<0.0001).
  
  
  CONCLUSIONS
  The presence of hyperdense areas was a significant risk factor for severe hemorrhagic transformations, although only 29.7% of patients with hyperdense areas had symptomatic hemorrhage. On the contrary, the absence of hyperdense areas was a reliable negative predictor for symptomatic hemorrhage.
authors.affiliation: Department of Neurosurgery, Miyazaki Medical College, Junwakai Memorial Hospital, Miyazaki, Japan. snakano@fc.miyazaki-med.ac.jp
authors.forename: S
authors.initials: S
authors.lastname: Nakano
authors.forename: T
authors.initials: T
authors.lastname: Iseda
authors.forename: H
authors.initials: H
authors.lastname: Kawano
authors.forename: T
authors.initials: T
authors.lastname: Yoneyama
authors.forename: T
authors.initials: T
authors.lastname: Ikeda
authors.forename: S
authors.initials: S
authors.lastname: Wakisaka
mesh_terms: D000208:Acute Disease; D000368:Aged; D000800:Angioplasty, Balloon; D001921:Brain / Q000098:blood supply / Q000000981:diagnostic imaging*; D002543:Cerebral Hemorrhage / Q000175:diagnosis / Q000209:etiology; D005119:Extravasation of Diagnostic and Therapeutic Materials / Q000150:complications / Q000175:diagnosis; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D020244:Infarction, Middle Cerebral Artery / Q000150:complications / Q000000981:diagnostic imaging* / Q000628:therapy*; D008297:Male; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015424:Reperfusion; D012307:Risk Factors; D014057:Tomography, X-Ray Computed