title: Intraoperative detection of early microvasospasm in patients with subarachnoid hemorrhage by using orthogonal polarization spectral imaging.
abstract: OBJECTIVE
  Changes of major cerebral vessels in patients with subarachnoid hemorrhage (SAH) are well known from routine cerebral angiography. Data on changes in the microcirculation do not exist. This study sought to provide a qualitative and quantitative analysis of the cortical microcirculation after SAH.
  
  
  METHODS
  By means of orthogonal polarization spectral imaging, a qualitative and quantitative analysis of cortical microcirculation was performed during aneurysm surgery in 3 patients with an incidental intracerebral aneurysm and 10 patients with SAH. Vessel diameters, red blood cell velocity, and functional capillary density were analyzed before and after the aneurysm was clipped.
  
  
  RESULTS
  Initial capillary density in patients with an incidental aneurysm was 91.5 +/- 36.5 cm(-1) (mean +/- standard deviation) compared with 30.5 +/- 13.8 in patients with SAH (P < 0.05). In patients with SAH, capillary density increased significantly to 53.9 +/- 29.1 cm(-1) (P < 0.05) during the operation, as did the frequency of venules with a red blood cell velocity greater than 2 mm/s (P < 0.05). No significant change of arteriolar or venular diameters was observed. However, in patients with SAH, mono- and multisegmental microvasospasms in arterioles were observed, with a reduction of vessel diameters up to 75.1%.
  
  
  CONCLUSIONS
  Orthogonal polarization spectral imaging is a suitable method to study cerebral microcirculation during surgery. In patients with SAH, capillary density is significantly decreased and small arteries and arterioles of the cortical surface exhibit vasospasm that cannot be detected by angiography or transcranial Doppler sonography. These changes may contribute to the initial clinical symptoms and may have an influence on the clinical postoperative course.
authors.affiliation: Department of Neurosurgery, Grosshadern University Hospital, Ludwig-Maximilians-University, Marchioninistrasse 15, D-81377 Munich, Germany. euhl@nc.med.uni-muenchen.de
authors.forename: Eberhard
authors.initials: E
authors.lastname: Uhl
authors.forename: Jens
authors.initials: J
authors.lastname: Lehmberg
authors.forename: Hans-Jakob
authors.initials: HJ
authors.lastname: Steiger
authors.forename: Konrad
authors.initials: K
authors.lastname: Messmer
mesh_terms: D000328:Adult; D002536:Cerebral Arteries / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D002550:Cerebral Veins / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D002560:Cerebrovascular Circulation / Q000502:physiology; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000175:diagnosis / Q000503:physiopathology* / Q000601:surgery*; D007431:Intraoperative Complications; D008297:Male; D008833:Microcirculation / Q000503:physiopathology; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000009:adverse effects*; D011048:Polarography; D011859:Radiography; D015203:Reproducibility of Results; D013057:Spectrum Analysis; D013345:Subarachnoid Hemorrhage / Q000175:diagnosis / Q000503:physiopathology* / Q000601:surgery*; D013997:Time Factors; D020301:Vasospasm, Intracranial / Q000175:diagnosis* / Q000209:etiology* / Q000503:physiopathology