What it means
Every imaging method has its own quirks. On CT, metal such as a hip replacement or dental fillings can cause bright and dark streaks. On MRI, small movements or breathing can blur the picture or create faint ghost copies. On ultrasound, gas and bone block the sound waves. These effects are called artifacts. They are tricks of the image, not real structures inside you.
When it matters
Most artifacts are minor and easy for radiologists to recognize. They matter when they hide part of the area being studied or look like a real finding. Phrases such as "limited by motion" or "degraded by artifact" tell your doctor that small findings could be missed there. Sometimes a repeat scan, a different position or another type of scan is suggested.
Questions to ask your doctor
- Did the artifact hide any part of the area my doctor wanted checked?
- Should the scan be repeated, or would a different scan avoid the problem?
- Is there anything I can do to help avoid it on the next scan?
