Is ingested glass visible on an X-ray (x-ray)?

Glass Visibility on X-ray

Glass can be seen on X-ray, but detection is highly variable and depends on fragment size, with false-negative rates up to 85% for small glass fragments in the gastrointestinal tract. 1

Radiographic Detection Rates

Size is the critical limiting factor for glass detection on plain radiography:

• 2.0 mm fragments: 99% detection rate 2
• 1.0 mm fragments: 83% detection rate 2
• 0.5 mm fragments: 61% detection rate 2
• Almost all glass foreign bodies can be detected radiographically when using appropriate technique, including high-resolution or mammographic techniques for minute splinters 3

Clinical Context Matters

For ingested glass in the gastrointestinal tract, plain X-ray has significant limitations:

• False-negative rates reach up to 85% for glass fragments along with other non-radiopaque objects like wood, plastic, fish bones, and chicken bones 1
• The overall false-negative rate for esophageal foreign bodies is up to 47% 1, 4
• Glass visibility is inconsistent, particularly when fragments are small or obscured by adjacent osseous structures 1

For glass in soft tissue (penetrating trauma), radiography performs better:

• Approximately 98% sensitivity for radiopaque foreign bodies including both leaded and non-leaded glass 1
• Two-view radiography (posteroanterior and lateral) is appropriate and cost-effective for screening 2

When X-ray is Negative But Clinical Suspicion Remains High

CT scan is the next essential step:

• CT has 90-100% sensitivity and 93.7-100% specificity for detecting foreign bodies 1, 4
• CT should be performed in symptomatic patients with suspected ingestion despite negative X-ray 1, 4
• CT is essential for locating non-radiopaque objects and evaluating complications like perforation, abscess, or obstruction 1, 4

For soft tissue glass foreign bodies with negative X-ray:

• Ultrasound can be used as an adjunct, though it has lower sensitivity than CT for glass detection 1
• CT is favored over MRI for foreign body identification 1

Common Pitfalls to Avoid

Do not rely solely on negative X-ray to exclude glass foreign body:

• In one series, glass foreign bodies were overlooked on 9 out of 26 patients' previous visits where examination was limited to inspection without radiography 3
• Even experienced radiologists may miss 33-50% of non-metallic foreign bodies, with false-positive identification occurring in 1-2 instances per radiologist 5

Do not delay endoscopy in symptomatic patients with suspected esophageal glass:

• Emergent endoscopy (within 2-6 hours) is required for sharp-pointed objects causing complete esophageal obstruction 1, 4
• Endoscopic evaluation should be performed even if radiographic examination is negative in patients with persistent esophageal symptoms 1