D uring two-dimensional transesophageal echocardiographic (2-D TEE) examination of the aortic arch, the proximal portion of the innominate artery (IA) can be frequently imaged; however, imaging of its distal portion and proximal branches is unusual because of the interposition of the trachea between the vessel and the ultrasound transducer. We report two elderly patients with stroke, referred for TEE to rule out a cardiac source of embolism, in whom we were able to image not only the full length of the IA, but also its bifurcation into right subclavian (RSA) and right common carotid (RCC) branches. CASE 1A 69-year-old white male was admitted to our institution with a transient ischemic attack characterized by an episode of dizziness lasting 5 minutes, associated with diplopia. The neurologic examination was normal except for mild finger-to-nose dysmetria. A computed tomographic scan of the head was normal. His medical history was significant for hypertension, aorto-bifemoral grafting, left vertebral artery angioplasty, and stenting of the proximal basilar artery. A 2-D TEE study with a biplane probe and a commercially available ultrasound system (Sequoia ® C 256, Acuson, Mountainview, CA) was done to rule out a cardiac source of embolism. No intra-cardiac thrombus or patent foramen ovale was found. The thoracic aorta was normal, except for mild, fixed atherosclerotic plaques. Toward the end of the TEE examination, the probe was positioned in the upper esophagus and the proximal portion of the IA was examined as previously described by our laboratory group. 1 By slowly withdrawing and carefully manipulating the probe from this position, we were able to follow the entire course of the IA until its bifurcation into RSA and RCC branches. Both vessels could be differentiated by color Doppler-guided pulsed Doppler interrogation. High-resistance antegrade systolic and retrograde diastolic flow signals characterized the RSA, while the RCC was identified by low-resistance flow with prominent antegrade flow signals in both systole and diastole (Figure 1). The IA measured 4 cm in length. The proximal portions of the left common carotid and left subclavian arteries, and the precervical portion of the left vertebral arteries, were also examined as described previously 2,3 and found to be normal. The hospital course remained stable and his neurologic examination was unchanged at the time of discharge. CASE 2A 79-year-old white female was admitted with two transient episodes of slurred speech and right-sided weakness occurring over a period of 12 hours. The patient had a medical history of type 2 diabetes mellitus, hyperlipidemia, and hypertension. The physical examination was unremarkable. Neurologic examination showed intact cranial nerves and no focal motor or sensory deficits. A computed tomographic scan of the head was normal. A 2-D TEE study was performed (with the same equipment as in the previous case) to exclude a cardiac source of embolism. A patent foramen ovale and moderate, fixed atherosclerotic plaques in the thor...

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