Which imaging technique can help identify retinal emboli in a patient with RAO?

Fluorescein angiography is the correct imaging technique for identifying retinal emboli in a patient with retinal artery occlusion (RAO). This procedure involves the intravenous injection of fluorescein dye, which circulates through the bloodstream and highlights the blood vessels in the retina when exposed to a specific wavelength of light. It allows for detailed visualization of the retinal circulation, helping to identify any blockages or abnormalities such as emboli.

Using fluorescein angiography provides valuable information regarding the vascular status of the retina, which is crucial in evaluating conditions like RAO. The technique can show areas of hypofluorescence where emboli may be obstructing blood flow or regions of retinal ischemia. Consequently, it aids in diagnosis and treatment planning.

Other imaging techniques listed, such as a CT scan of the abdomen and x-ray imaging, are not designed to provide detailed views of the retinal structures or blood flow within the eye. Although an ultrasound of the heart can be useful for detecting potential sources of emboli, it does not visualize the retinal vessels directly and cannot identify emboli in the retina itself. Thus, fluorescein angiography is specifically tailored for assessing the retinal vasculature, making it the appropriate choice in this context.