Rarely, a hypodense artery sign can occur due to fat embolism.

[7] Through cerebral angiography, the sign has been demonstrated to correspond to embolic or atherosclerotic occlusion of an artery.

[1] Specifically, the hyperdensity is thought to be due to calcification or hemorrhage associated with an atherosclerotic plaque.

[1] Identification of the dense artery sign is often based on subjective interpretation and false positives may occur.

One study aiming to define criteria for the sign determined that measuring Hounsfield units on the CT scan could differentiate between the dense MCA sign associated with ischemic stroke and that caused by false positives.