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Title: The detection of intracranial aneurysms by non-invasive imaging methods and the epidemiology of aneurysmal subarachnoid haemorrhage within the Scottish population
Author: White, P. M.
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 2004
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The aims of the research project, which led to the writing of this thesis were to: Examine whether non-invasive imaging methods could replace intra-arterial angiography (IADSA) in the detection of intracranial aneurysms by: a) systematically reviewing the literature; b) prospectively determining the accuracy of non-invasive imaging methods currently available to Scotland, including the effect of observer experience on diagnostic performance and the patient acceptability of the alternative imaging modalities. To establish the incidence of aneurysmal subarachnoid haemorrhage (SAH) in families by a national retrospective study of occurrences of SAH in a one year period in Scotland, in parallel with a follow-up study of the families of patients who were admitted to the Institute of Neurosciences with aneurysmal SAH a decade earlier. The thesis is divided into three parts: Part One: a) summarises the current understanding of the epidemiology and pathophysiology of intracranial aneurysms; b) an overview of cerebrovascular anatomy with reference to aneurysm formation; c) the modalities available for imaging intracranial aneurysms and the current knowledge about their diagnostic performance are considered; d) an overview of the methods available for the treatment of intracranial aneurysms; e) the concept of screening for unruptured intracranial aneurysms is discussed and placed in context by comparison to other screening programmes. Part Two: a) describes a systematic review of the non-invasive imaging of intracranial aneurysms. CT and MR angiography had similar accuracy compared to IADSA of ~90%. Data on Transcranial Doppler Sonography (TCDS) were scantly but indicated poorer performance. Detection of very small aneurysms (<3 mm diameter) was significantly poorer for the non-invasive tests; b) describes a prospective study of 200 patients examining CTA, MRA and TCDS vs IADSA in the detection of intracranial aneurysms. CTA and MRA had an accuracy (per subject) of 0.85. TCDS had similar accuracy per subject but poorer accuracy per aneurysm than CTA or MRA. Detection of aneurysms £5mm was significantly poorer than for those >5mm. Interobserver agreement was good for all modalities; c) combining TCDS with CTA or MRA improved the detection of aneurysms on a per subject basis. Non-invasive imaging tests, especially when used in combination, are reliable at detecting aneurysms >5mm; d) examines the effect of observer experience. Neuroradiologists were more consistent and had better agreement with IADSA than non-neuroradiologists. Small aneurysms and cavernous/terminal internal carotid aneurysms were poorly detected by all observers; e) assessment of patient preferences indicated that TCDS was preferred to the other non-invasive tests and CTA or MRA, with the differences being statistically significant.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (M.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available