M. Yasaka, Y. Wakugawa, M. Mori, Y. Nakanishi, Y. Okada
Kyushu Medical Center – Fukuoka, Japan
Objective: We attempted ultrasonographic evaluation of the distal extracranial internal carotid artery (ICA) in patients with extracranial ICA dissection by using the transoral carotid ultrasonography (TOCU).
Material and Methods: The subjects consisted of 5 healthy volunteers (33 ± 5 years old) and 5 extracranial ICA dissection patients (45 ± 4 years old). Examinations were performed using a color Doppler flow imaging system equipped with thin and long convex array transducers (9-5 MHz). We inserted a probe covered with thin gum transorally, touching the tip to the pharyngeal postero-lateral wall. We then attempted to detect the ICA and measure ICA diameter and flow velocity of the distal extracranial ICA by TOCU.
Results: TOCU was successfully performed in all subjects without any difficulty. In the healthy volunteers, the ICA was identified at a depth of 2.2±0.6 cm and visualized as a vertical linear vessel 2.9±0.3 cm in length and bent slightly backwards (Yasaka M, et al.: Stroke 1998; 29;1383-8). The diameter and mean flow velocity of the distal extracranial ICA was 4.7±0.2 mm and 50±7 cm/s, respectively. In the ICA dissection patients, some remarkable findings were obtained, including dilatation of ICA (7.8±2.2, ranging from 6.8 to 10.0 mm, p<0.01), visualization of true and false lumens and improvement of the affected ICA by following TOCU performed 2-4 weeks later.
Discussion: TOCU seems useful in evaluation of extracranial ICA dissection.
Key words: dissection, internal carotid artery, transoral ultrasonography.