title: Does the size of intracranial aneurysms change with intracranial pressure? Observations based on color "power" transcranial Doppler ultrasound.
abstract: OBJECTIVE
  The authors sought to determine whether the increased pulsatility of aneurysms, compared with normal intracranial arteries, on color "power" transcranial Doppler (TCD) ultrasound was due to a true change in aneurysm size and whether aneurysm dimensions change with intracranial pressure (ICP).
  
  
  METHODS
  The authors studied nine patients who had suffered recent subarachnoid hemorrhages complicated by hydrocephalus requiring intraventricular cerebrospinal fluid drainage, in whom the presence of an aneurysm was confirmed on angiographic examination. Color "power" TCD studies of the intracranial arteries and aneurysm were obtained through the temporal bone window before and after insertion of the ventricular drain and then at different known ICPs. Of the nine patients studied, four were examined both before and after insertion of a ventricular drain. At high ICPs, aneurysms appeared very "pulsatile" and the maximum cross-sectional area was small, whereas at low ICPs, aneurysms appeared larger and were much less pulsatile. The normal arteries did not change significantly in terms of pulsatility or maximum cross-sectional area at different levels of ICP.
  
  
  CONCLUSIONS
  The change in aneurysm size visualized with the aid of color power TCD is likely to be real. Aneurysm dimensions vary with ICP levels; the lesions are larger and less pulsatile at low ICPs and smaller but more pulsatile at high ICPs.
authors.affiliation: Department of Clinical Neurosciences, Western General Hospital National Health Service Trust, Edinburgh, United Kingdom.
authors.forename: J M
authors.initials: JM
authors.lastname: Wardlaw
authors.forename: J
authors.initials: J
authors.lastname: Cannon
authors.forename: P F
authors.initials: PF
authors.lastname: Statham
authors.forename: R
authors.initials: R
authors.lastname: Price
mesh_terms: D019412:Anatomy, Cross-Sectional; D001794:Blood Pressure / Q000502:physiology; D002533:Cerebral Angiography; D002536:Cerebral Arteries / Q000000981:diagnostic imaging / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology; D003971:Diastole; D004322:Drainage; D006801:Humans; D006849:Hydrocephalus / Q000209:etiology / Q000601:surgery; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D007427:Intracranial Pressure / Q000502:physiology*; D015588:Observer Variation; D011673:Pulsatile Flow / Q000502:physiology; D013345:Subarachnoid Hemorrhage / Q000150:complications; D013599:Systole; D013701:Temporal Bone; D018615:Ultrasonography, Doppler, Color; D017585:Ultrasonography, Doppler, Transcranial