A patient presents with a hip fracture, carotid bruit, weakness, and confusion. What imaging study should be ordered?

In the context of this patient's presentation, a carotid ultrasound (C) is the most appropriate imaging study to order. Carotid ultrasound is a non-invasive and highly effective tool for evaluating carotid artery diseases, such as stenosis or occlusion, particularly when there is evidence of carotid bruit and neurological symptoms like confusion and weakness.

The presence of a carotid bruit suggests turbulent blood flow, likely due to an obstruction or narrowing in the carotid artery, which could lead to decreased cerebral perfusion or embolic events affecting neurological function. An ultrasound can quickly assess for the presence of plaque, measure the degree of stenosis, and help determine if there is a significant risk of stroke.

Ordering a carotid MRI or CT would involve exposure to radiation or contrast that may not be immediately necessary and could complicate timely management. A cervical spine X-ray may not be relevant to the specific neurological symptoms presented, as it does not address the potential vascular issues indicated by the carotid bruit. Therefore, the carotid ultrasound stands out as the most appropriate diagnostic study in this scenario.