Imaging description

In very heterogeneous cross sections, dark (low-attenuation) bands or streaks can appear between two dense objects in an image. They occur because the portion of the beam that passes through one of the objects at certain tube positions is hardened less than when it passes through both objects at other tube positions [1]. This type of artifact can occur in bony regions of the body; in scans where contrast medium has been used; and from lines, devices, and surgical clips. The artifact is usually nonanatomic, poorly defined, and radiating [2].

Importance

Streak artifacts from dense contrast in the superior vena cava (SVC) are common, and can be seen overlying the right main and right upper lobe pulmonary arteries. These areas of decreased attenuation can be mistaken for intraluminal filling defects (Figure 84.1), or they could obscure the vessels for accurate assessment for pulmonary embolism. Similar artifacts arise from pacemaker leads, surgical clips, or similar structures.