title: [Spontaneous hyperdense intracranial vessels seen on CT scan in polycythemia cases].
abstract: OBJECTIVE
  A better understanding of the significance of diffuse hyperdensity affecting the circle of Willis and the dural sinuses on unenhanced CT.
  
  
  METHODS
  We performed a retrospective study of 19 patients with a neurological manifestation and a CT scan without contrast injection. Among these 19 patients, six had been included because of primary or secondary polycythemia. The analysis of cerebral CT scans was made qualitatively by visual inspection and quantitatively.
  
  
  RESULTS
  In patients with a hematocrit percentage exceeding 60%, both circle of Willis and dural sinuses were dense on unenhanced CT scans. A linear relation between the hemoglobin level and the contrast of the dural sinuses compared with the grey matter was observed with an excellent correlation (r = 0.934; n < 0.0001; p = 19).
  
  
  CONCLUSIONS
  Increased density of cerebral vessels on unenhanced CT is a sign of a high hemoglobin level.
mesh_terms: D000328:Adult; D000368:Aged; D002536:Cerebral Arteries / Q000000981:diagnostic imaging*; D002550:Cerebral Veins / Q000000981:diagnostic imaging*; D002648:Child; D002941:Circle of Willis / Q000000981:diagnostic imaging*; D003392:Cranial Sinuses / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D005260:Female; D006400:Hematocrit; D006454:Hemoglobins; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D011086:Polycythemia / Q000097:blood / Q000000981:diagnostic imaging* / Q000473:pathology; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods / Q000592:standards
chemical_list: D006454:Hemoglobins
vernacular_title: Vaisseaux intracrâniens spontanément hyperdenses au scanner en cas de polyglobulie.