Which anatomical condition is shown to cause high velocities in the celiac artery during expiration?

The anatomical condition that causes high velocities in the celiac artery during expiration is indeed median arcuate ligament compression. This condition arises when the median arcuate ligament, which is a fibrous band that connects the two sides of the diaphragm, compresses the celiac artery.

During expiration, the diaphragm moves upwards, which can increase the tension on this ligament and lead to an enhanced compression of the celiac artery. As a result, the blood flow through the artery can become turbulent and accelerated, thus resulting in high flow velocities as detected in Doppler ultrasound studies. This phenomenon is particularly pronounced during certain respiratory phases because the position of the diaphragm alters the degree of compression on the celiac artery.

The other conditions mentioned, while they may cause abnormal vascular flow dynamics, do not specifically result in the characteristic high-velocity flow in the celiac artery associated with expiration. For instance, arterial stenosis commonly leads to increased velocities due to narrowing but does not have the specific respiratory relationship seen with median arcuate ligament compression. This unique response during the respiratory cycle makes median arcuate ligament compression the correct choice for this question.