Fig. 1.

Arterial compression hook sign. a “Arterial compression hook sign”-positive case. On expiration, narrowing of the celiac artery origin due to compression by the high echoic structure (red arrow; hypertrophied median arcuate ligament) can be observed and subsequently shows the “arterial compression hook sign”. b “Arterial compression hook sign”-negative case. The celiac artery has an angular deflection, but no root stenosis. c “Arterial compression hook sign”-negative case. The celiac artery is straight without angular deflection. CA celiac artery, Ao aorta