부산대학교 도서관

IntroductionTherapeutic intervention, both in the acute phase of stroke and in the secondary prevention of ischaemic stroke, requires a precise aetiological diagnosis. The introduction of more sophisticated diagnostic techniques such as duplex colour ultrasonography, transcranial Doppler (TCD) and transoesophageal echocardiography (TEE) has shown the clinical importance of the embolic mechanism, which most modern stroke data banks show to be the most frequent cause of ischaemic stroke. However, the potential source of cerebral emboli is unknown in a high percentage of patients. Currently cerebral embolism is considered to be a phenomenon caused by an occlusion of the artery in which the embolus occurs, independently to whether or not the source of the embolus is known (heart, aorta, or proximal arteries).New transcranial Doppler techniques which are capable of detecting the existence of cerebral microemboli (MES) are giving encouraging results and although the full significance of MES is still not fully understood, it is becoming ever more apparent that the detection of this phenomenon may have both prognostic and therapeutic implications.Objectives of the studyPrimary objectiveTo determine the clinical utility of the detection of cerebral microemboli through transcranial Doppler in patients with acute ischaemic stroke. In order to achieve this the following specific objectives, outlined for each stage of the study, were set.Stage I. Investigation I.The usefulness of TCD with contrast (TCD-c) in the diagnosis of Right-to-Left shunt (RLSh) in young adults.4. To analyse the prevalence of RLSh in ischaemic stroke in young adults.5. To compare the efficacy of transthoracic echocardiogram with contrast (TEE-c) with TCD-c.6. To evaluate the importance of RLSh as a potential risk factor in cryptogenic ischaemic stroke.Stage II. Investigation II. The usefulness of TCD-c in the diagnosis of RLSh: the need to quantify RLSh.6. To determine the prevalence of RLSh in a healthy population.7. To determine the prevalence of RLSh in acute ischaemic stroke in all age groups and stroke subtypes.8. To determine the importance of RLSh as a vascular risk factor.9. To determine the sensibility and specificity of TCD-c with respect to the transoesophageal echocardiogram with contrast (TEE-c) in patients with cryptogenic stroke.10. To determine the capacity of TCD-c in the quantification of the magnitude of cardiac RLSh.Stage II. Investigation III. The detection of solid microemboli through TCD in acute ischaemic stroke.4. To study the prevalence of MES in a non-selected patient group with acute ischaemic stroke.5. To detect and confirm the embolic origin of suspected or known sources of embolic strokes. 6. To determine the prognostic value of the detection of MES in acute ischaemic stroke: severity of stroke, early recurrence and dependency.Material and methodThe study which we present in this thesis is undertaken in 2 stages, which differ from one another essentially in that the first has a more immediate objective and uses more elementary and widely available technology. The results of the first study led us to design and develop a wider and more ambitious study both with respect to the aims which were proposed and the resources which were used. The development of the project and the resulting publications are summarised in the following table