経口腔頚部血管超音波検査法（ｔｒａｎｓｏｒａｌ ｃａｒｏｔｉｄ ｕｌｔｒａｓｏｎｏｇｒａｐｈｙ，ＴＯＣＵ）の開発と応用

Abstract

We developed transoral carotid ultrasonography, TOCU, which enabled us to evaluate the distal extracranial internal carotid artery (ICA) using the transoral method in 1998 and applied it to patients with carotid occlusive disease, moyamoya disease, or carotid arterial dissection. Examinations were performed using a color Doppler flow imaging system equipped with a stick-like convex array transducers (9-5 MHz). We inserted a transducer covered with thin gum transorally, touching the tip to the pharyngeal postero-lateral wall. We then attempted to detect the ICA and measure flow velocity of the distal extracranial ICA using principal images obtained by TOCU. In the healthy five volunteers, the ICA was identified at a depth of 2.2±0.6cm and visualized as a vertical linear vessel 2.9±0.3 cm in length and bent slightly backwards. The diameter and mean flow velocity of the distal extracranial ICA was 4.7±0.2mm and 50±7cm/sec, respectively. In the stroke patients, some remarkable findings were obtained, including a dilated ICA with narrow true lumen in a patient with ICA dissection, a lucent echo without flow signal in a patient with acute cardioembolic ICA occlusion, and decreased ICA diameter less than 3.0mm in a patient with pseudo-occlusion of the ICA or moyamoya disease. The TOCU is a helpful method as the procedure of compensating conventional carotid ultrasonography.