Abstract 208: Non-gated Cardiac Ct Angiograms for Detection of Embolic Sources in Acute Ischemic Stroke

Background and Purpose: We assessed the diagnostic feasibility of using a 2-phase 64-slice non-gated cardiac computed tomographic angiography (CTA) in acute stroke patients, done in the same sitting as the brain CTA and using the same contrast dose, for the detection of a cardiac source of embolism. We expected to identify additional causes of stroke related to other unexpected pathology of heart or ascending aorta, which might be useful in therapeutic decision making and prognostication. Methods: We recruited 20 consecutive patients with acute ischemic stroke within the 4.5hours of symptom-onset, activated for intravenous thrombolysis. In addition to our usual CTA protocol that spanned from the arch of aorta to the circle of Willis, we enlarged the field of scanning to include the heart. Radio-contrast load (Omipaque 350) remained unchanged (injected at 3-4ml/sec; total 60-80mls, triggered by bolus tracking). All scans were 0.5cm thick slices and were reviewed by a radiologist and cardiologist and the abnormal findings were conveyed to the treating neurologist. In patients with potential cardiac source of embolism, an urgent trans-thoracic or trans-esophageal echocardiogram was arranged. Results: Of 20 patients, there were 3 abnormal findings, 1patient had a ventricular thrombus , 1 had a localized dissection in the ascending aorta and the third patient had a thrombus at the atrial appendage. Both were confirmed by trans-esophageal echocardiography and anticoagulation was started urgently the next day. None of our patients developed contrast nephropathy on follow up. Conclusions: expanding the field of scanning to include the heart and ascending aorta ( a non-gated cardiac CTA) to the routinely performed CTA of cervico-cranial arterial tree is a noninvasive and useful modality for detecting high-risk cardiac and aortic sources of embolism in acute stroke patients.