title: Multidetector computed tomographic angiography in isolated third nerve palsy.
abstract: OBJECTIVE
  To evaluate whether multidetector computed tomographic angiography (CTA) scanners can detect a clinically significant intracranial aneurysm in the circle of Willis causing an isolated third nerve palsy (ITNP).
  
  
  METHODS
  Retrospective cross-sectional study.
  
  
  METHODS
  One hundred thirty-seven patients who presented with an ITNP were examined by multidetector CTA scanners.
  
  
  METHODS
  All patients whose symptoms were caused by a compressive cerebral aneurysm were identified. The remaining patients were observed clinically to exclude the possibility of a missed cerebral aneurysm causing the ITNP. No patient underwent diagnostic conventional cerebral angiography (CCA), but all patients who underwent treatment underwent CCA at the time of the treatment.
  
  
  METHODS
  Accurate identification of a cerebral aneurysm that may cause an ITNP.
  
  
  RESULTS
  A cerebral aneurysm causing an ITNP was detected in 27 patients (19.7%). The smallest maximal diameter of a clinically significant aneurysm was 5.7 mm. Of the 27 patients, 25 underwent endovascular coiling at which time CCA confirmed the aneurysm. In no case was another lesion found by CCA. Of the patients without an aneurysm, 81 of 110 (74%) made a complete spontaneous recovery. In no patient was there clinical evidence to suggest that a compressive cerebral aneurysm had been missed on CTA.
  
  
  CONCLUSIONS
  Multidetector CTA is a safe and effective diagnostic imaging tool in detecting clinically significant aneurysms when a patient presents with an acute ITNP. We no longer perform CCA to detect a causative aneurysm or determine the type of treatment offered in these patients.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Nottingham, Nottingham, United Kingdom.
authors.forename: Manu R K
authors.initials: MR
authors.lastname: Mathew
authors.forename: Evelyn
authors.initials: E
authors.lastname: Teasdale
authors.forename: Robert M
authors.initials: RM
authors.lastname: McFadzean
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002533:Cerebral Angiography; D003287:Contrast Media; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D002532:Intracranial Aneurysm / Q000150:complications / Q000000981:diagnostic imaging*; D007483:Iothalamic Acid; D008297:Male; D008875:Middle Aged; D015840:Oculomotor Nerve Diseases / Q000000981:diagnostic imaging* / Q000209:etiology; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007483:Iothalamic Acid