 Elucidating the underlying cause of a syncopal or presyncopal episode can be challenging. There are numerous potential cardiovascular or neurologic etiologies, many of which rely on appropriate imaging for identification and classification; these include coronary artery disease, aortic disease, and cardiomyopathies. Although the etiology is never discovered in one-third of patients [10], and some causes such as vasovagal syncope are relatively innocuous, others, such as cardiac-related syncope, carry a significant increased risk of death [10-13]. The mainstay of syncope and presyncope assessment is a detailed history and physical examination. The assessment should include measurement of postural changes in blood pressure to diagnose orthostatic-related syncope and a detailed neurologic history and physical examination to exclude symptoms or signs of a separate neurologic process, which would require a different course of evaluation [14]. In addition to a detailed cardiac examination assessing for structural heart disease, certain patient characteristics are associated with an increased risk of cardiac-related syncope and include the following: age >60 years, male gender, known underlying congenital or acquired cardiac disease, palpitations or other cardiac-related symptoms prior to syncopal episode, syncope during exertion, syncope in supine position, low number of prior syncopal episodes, and family history of sudden cardiac death [3]. Studies have shown that patients with syncope and presyncope have a low yield of 5% to 6.4% of an acute abnormality on head CT, nearly all with external evidence of head trauma or a focal neurological deficit on examination [15-19]. Increasing age has been associated with higher odds for a CT abnormality compared with younger patients with syncope, however, the age cutoffs of >55 [15] or 60 and older [19] have not been validated across studies as independent predictive factors in absence of trauma or neurologic deficit [20].
Syncope.  Elucidating the underlying cause of a syncopal or presyncopal episode can be challenging. There are numerous potential cardiovascular or neurologic etiologies, many of which rely on appropriate imaging for identification and classification; these include coronary artery disease, aortic disease, and cardiomyopathies. Although the etiology is never discovered in one-third of patients [10], and some causes such as vasovagal syncope are relatively innocuous, others, such as cardiac-related syncope, carry a significant increased risk of death [10-13]. The mainstay of syncope and presyncope assessment is a detailed history and physical examination. The assessment should include measurement of postural changes in blood pressure to diagnose orthostatic-related syncope and a detailed neurologic history and physical examination to exclude symptoms or signs of a separate neurologic process, which would require a different course of evaluation [14]. In addition to a detailed cardiac examination assessing for structural heart disease, certain patient characteristics are associated with an increased risk of cardiac-related syncope and include the following: age >60 years, male gender, known underlying congenital or acquired cardiac disease, palpitations or other cardiac-related symptoms prior to syncopal episode, syncope during exertion, syncope in supine position, low number of prior syncopal episodes, and family history of sudden cardiac death [3]. Studies have shown that patients with syncope and presyncope have a low yield of 5% to 6.4% of an acute abnormality on head CT, nearly all with external evidence of head trauma or a focal neurological deficit on examination [15-19]. Increasing age has been associated with higher odds for a CT abnormality compared with younger patients with syncope, however, the age cutoffs of >55 [15] or 60 and older [19] have not been validated across studies as independent predictive factors in absence of trauma or neurologic deficit [20].