Submandibular TCD approach detects post-bulb ICA stenosis in children with sickle cell anemia

Transcranial Doppler (TCD) ultrasound is a procedure commonly used to screen individuals with the major hemoglobin S diseases, Hb SS and Hb S-beta(0), for significant stenoses in the circle of Willis. Flow velocities above 200 cm/s have been shown to identify patients at elevated risk for cerebral infarction. Among TCD's limitations is the inability to insonate the distal extracranial, petrous, and cavernous internal carotid artery (ICA) through the standard transtemporal approach. We extended the submandibular approach to include infra-siphon portions of the ICA. Using the extended submandibular approach to evaluate these portions of the ICA, we identified stenotic lesions in 4 patients with Hb SS disease out of a population of 131 children with Hb SS. Three of the 4 patients had no history of overt stroke or stroke-like symptoms. Neuroimaging confirmed the stenotic lesions, and also revealed watershed infarction as well as discrete areas of silent infarction. All 4 children had neuropsychological impairment. The submandibular approach, when added to a standard transcranial Doppler examination, may increase the sensitivity of this technique to identify important potential sources of cerebral infarction.