超音波検査技術

A woman in her 50s was admitted to our hospital due to sudden dysarthria and left paresis. She had a history of pulmonary embolism and cerebral embolism; thus, she was receiving anticoagulant therapy. Emergent endovascular thrombectomy was performed to treat the acute cerebral embolism in the right middle cerebral artery. Transthoracic echocardiography (TTE) revealed right ventricular enlargement and leftward ventricular septal shift with an increase in tricuspid systolic pressure gradient. A contrast-enhanced computed tomography revealed a pulmonary embolisms and deep vein thrombosis. Pulmonary blood flow scintigraphy, pulmonary angiography, and right heart catheterization suggested recurrence of pulmonary embolism following chronic thromboembolic pulmonary hypertension (CTEPH). Since cerebral embolism occurred due to the right-sided pressure overload due to pulmonary hypertension; pathologically, paradoxical cerebral embolism was strongly suspected in this patient. In the microbubble tests by TTE and transcranial color Doppler imaging (TCCFI), a massive right-to-left shunt at the atrial level in the TTE and a large number of micro-embolic signals in TCCFI were confirmed without performing the Valsalva maneuver. Transesophageal echocardiography confirmed a patent foramen ovale and right-to-left shunt flow at rest, and the microbubble test was positive at grade 3 in the left atrium. Thus, we treated a case of venous thrombosis that developed paradoxical cerebral embolism through the foramen ovale in a patient with CTEPH. Here we report the diagnostic approach and the importance of ultrasonography for such a pathologically complicated condition.