Dense Vessels Simulating Thrombosis on Nonenhanced CT

Abstract

A normal appearance of hyperdense vessels, whether arterial or venous, can occur on nonenhanced CT (NECT) for several reasons. This appearance can represent a true increase in density, or it can be artifactual. Notably, there is a correlation between the hemoconcentration of whole blood and the density on NECT. Hence, higher hemoglobin and/or higher hematocrit levels may lead to relatively hyperdense vessels diffusely on NECT, which is most commonly due to frank dehydration in patients without stroke symptoms presenting to the emergency room. Thus, higher hemoconcentrations can lead to a hyperdense appearance of the arteries and dural sinuses, whether due to a relative polycythemia, which can occur with decreased fluid intake or fluid loss or with a higher hematocrit, such as that occurring normally in newborns. Because newborns do have some risk for venous thrombosis, it is occasionally necessary to implement contrast-enhanced MR venography (CEMRV) or CT venography (CTV) to exclude venous thrombosis. Also, artifactual vascular hyperdensity can occur unilaterally or bilaterally at the skull base as a result of artifacts from beam hardening (decreased penetration in areas of dense bones or metal), patient motion, or volume averaging (such as the middle cerebral artery volume averaged with adjacent cerebrum or subarachnoid space).