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The assessment of extracranial intrenal carotid artery disease
Başlık:
The assessment of extracranial intrenal carotid artery disease
Yazar:
Murie, John Andrew, author.
ISBN:
9780438060654
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (245 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 76-08C.
Advisors: Roger O. Quinn.
Özet:
This thesis discusses modern methods of assessing disease of the extracranial internal carotid artery in patients with transient cerebral ischaemia. The techniques described are based either on ultrasonic changes observed from within the artery itself or on alterations in cerebral blood flow distal to the vessel. In both instances, comparison is made with X-ray contrast angiography which is still regarded as the "gold standard" of arterial assessment. Because of the central importance of contrast radiology in this thesis, attention has been given to the reproducibility of the recording from angiograms of extent of disease by different observers and by the same observer on different occasions. When a small number of X-ray categories were used, generally ≥0 to <25%, ≥25 to <100% stenosis and occlusion, good agreement occurred on a repeatable basis. X-ray data have also shown that the population studied is similar to that described from other centres in terms of frequency and distribution of extracranial cerebrovascular atheroma. The importance of the internal carotid origin as the major site of such disease was confirmed. The simplest method of non-invasive assessment of the internal carotid is auscultation for bruit, A correlation between clinically observed bruit and internal carotid stenosis (by X-ray) or intraluminal turbulence (using pulsed Doppler ultrasonography) demonstrated that audible "carotid bruit" was associated with internal carotid disease in only 60 to 70% (depending on the definition of disease) of instances. A bruit was often present when arterial disease was absent and, conversely, was often absent when gross internal carotid pathology was obvious on both X-ray and ultrasonography. Carotid bruit did not seem useful as a diagnostic criterion of disease. A short history of non-invasive carotid artery investigation is followed by a description of the theoretical concepts involved in ultrasonography. Pulsed Doppler ultrasonography may be used to produce an image of the carotid on an oscilloscope screen. Using such an imaging technique, although an accuracy of 96% in the detection of internal carotid occlusion was achieved, the accuracy of detection of stenosis was poor. Ultrasonic frequency/time spectra, obtained from an accurately defined site within the vessel using the above imaging technique, were then examined. Spectral changes in the common carotid (ie. proximal to a putative stenosis) were expressed as either the Pourcelot Index or the A/B ratio. Neither yielded a sufficiently high accuracy to allow their recommendation as a test for internal carotid disease. Frequency/time spectra from sites immediately distal to the internal carotid origin were then investigated. The feature of spectrum broadening, typical of intraluminal turbulence, was commonly found in association with arterial narrowing. Using this as the criterion of disease, an accuracy of detection of internal carotid stenosis (≥25% by X-ray) of 95% was obtained.
Notlar:
School code: 0547
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Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(684834.1) | 684834-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
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