Artifact — What It Means on Your Imaging Report

Quick Answer

An artifact is something that appears on your imaging scan but is not actually in your body — like a visual glitch that radiologists are trained to recognize.

What Is an Artifact?

In medical imaging, an artifact is any feature that appears on a scan that does not represent actual anatomy or disease. It is a distortion, shadow, blur, or bright spot caused by the imaging process itself rather than something inside your body. Every imaging technology — X-ray, CT, MRI, and ultrasound — can produce artifacts.

Think of it like a smudge on a camera lens or a streak of light that appears in a photograph when you point the camera toward the sun. The smudge or streak is not really part of the scene you photographed — it is created by the camera. In the same way, an artifact on a medical image is created by the scanner, patient movement, or external objects, not by your body.

Radiologists undergo years of training to distinguish artifacts from real findings. When a radiologist mentions an artifact in your report, they are documenting that they noticed the distortion and recognized it for what it is — not a medical concern. Common types include:

• Motion artifact — caused by patient movement during the scan. Even breathing or a heartbeat can create slight blurring, especially on MRI.
• Metallic artifact — caused by metal objects such as surgical implants, dental fillings, or jewelry. Metal distorts the surrounding image, creating bright streaks or dark voids.
• Beam hardening artifact (CT) — occurs when the X-ray beam passes through very dense structures like bone or metal, creating dark bands or streaks.
• Susceptibility artifact (MRI) — happens near areas where metal is present or different tissue types meet, causing signal distortion.
• Acoustic shadowing (ultrasound) — occurs when sound waves cannot pass through a dense structure (like a gallstone), creating a dark shadow behind it. This artifact is actually helpful because it confirms the structure is solid and dense.

When You Might See This on Your Report

Artifacts are mentioned across all imaging types when they affect image quality or could potentially be confused with a real finding:

• MRI reports — motion and susceptibility artifacts are the most commonly mentioned. You might see "motion artifact limits evaluation of..." or "susceptibility artifact from prior surgical hardware."
• CT scan reports — beam hardening and metallic artifacts are frequently noted, especially in patients with dental implants, joint replacements, or spinal hardware.
• X-ray reports — overlying objects (jewelry, clothing snaps, EKG leads) or patient positioning issues may be noted.
• Ultrasound reports — acoustic shadowing is common and often diagnostically useful.

You may see language like "artifact degrades image quality" or "metallic artifact limits evaluation of the adjacent tissue." These statements explain why certain areas could not be fully assessed.

Should I Be Worried?

No — an artifact is not a medical finding, and radiologists are experts at identifying them. When your report mentions an artifact, it means the radiologist recognized the distortion and is being transparent about what they see.

There are two scenarios worth understanding:

When an artifact is simply documented: This is the most common case. The radiologist notes it for completeness — for example, "metallic artifact from dental fillings noted" is a factual statement with no clinical concern.

When an artifact limits evaluation: Sometimes an artifact obscures part of the image. The report may say "evaluation of the posterior fossa is limited by susceptibility artifact." If the obscured area is clinically important, the radiologist may recommend a different imaging technique or a repeat scan. This simply means a particular area could not be clearly seen and may need to be evaluated another way — it is not cause for alarm.

What Should I Do Next?

1. Remove all metal objects before your scan. Jewelry, watches, belt buckles, hair clips, and clothing with metal fasteners should be removed. Your technologist will remind you, but being prepared helps.
2. Stay as still as possible during imaging. Motion is the most common preventable cause of artifacts, especially during MRI. Follow the technologist's breathing instructions carefully.
3. Tell your technologist about any implants or surgical hardware. Knowing about metal in your body ahead of time helps the team choose the best imaging technique and settings to minimize artifact.
4. If your report says the artifact "limits evaluation," ask your doctor whether additional imaging is needed. In many cases, the important clinical question was still answered despite the artifact. Your doctor can determine whether further action is warranted.
5. Use ReadingScan to understand artifact-related language in your report and see whether the artifact affected any clinically significant findings.