**7. CT angiography**

Another non-invasive diagnostic tool in patients presenting with chest pain, ST segment elevation and elevated cardiac biomarkers is the use of the 64-slice coronary CT angiography (CCTA) which is a reliable test that can be utilized in patients with low to intermediate pretest probability for coronary artery disease. Shturman et. al. used the 64 slice CCTA to rule out coronary artery disease in a case of perimyocarditis mimicking myocardial infarction [40]. This simple noninvasive test and can avert the unnecessary need for coronary angiography or thrombolytic therapy for a presumed STEMI. Recently, Computed tomographic angiography (CTA) "triple rule out" protocol has been utilized in the emergency department for patients presenting with acute chest pain to differentiate between pulmonary embolism, aortic dissection and acute coronary syndrome. Compared with the usual radiation dose of a standard 64-slice CCTA, the effective radiation dose of a "triple rule-out" scan is often increased by 50% which should limit its unrestricted use. Takakuwa et. al. reported the successful use of the "triple rule-out" scan in diagnosing acute perimyocarditis (figure 4) and excluding other serious etiologies as acute coronary syndrome, aortic dissection and pulmonary embolism [41].
