Chapter 26
Foreign Bodies
Abdomen and Superficial Structures
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Objectives
• Identify and give examples of different types of soft
tissue foreign bodies based on composition.
• Explain sensitivity and specificity.
• List the important information the sonographer should
obtain from the patient interview and patient chart prior
to providing a comprehensive sonography evaluation.
• Differentiate the different sonographic appearances of
soft tissue foreign bodies based on composition, location,
age, and artifacts.
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Objectives
• Describe the role of the sonographer prior to, during, and
following sonography guided foreign body removal.
• Explain the limitations of sonography and the advantages
of other imaging modalities used to image soft tissue
foreign bodies.
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Composition of Foreign Bodies
Organic
Plant material (thorn, wood, etc.)
Animal products (bee stinger, barb, etc.)
Inorganic
Glass, gravel, plastic (acrylic), pencil lead,
graphite, etc.
Metallic
Wire, needle, fish hook, etc.
Radiography detects only 15% or less of
radiolucent foreign bodies (wood, plastic, glass,
and cactus spine)
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Transducer
• Large Footprint Screening
• 7-12 MHz
• High Resolution
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Increasing Near Field Length
Water Bath Technique
• Increase visualization of skin surface.
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Increasing Near Field Length
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Edge Shadowing Artifacts
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Speckle Reduction Imaging & Hyperemic
Flow Inflammatory Rxn
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Using Anatomy to Locate Foreign Bodies
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Foreign Body Location
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Age of the Foreign Body
Acute Phase
Injury less than 3 days
Bright, Echogenic, Shadowing
After 24 hours – hypoechoic halo
develops (inflammatory rxn)
Intermediate Phase
Injury within 3 to 10 days
Air replaced by fluid, No shadowing,
Hypoechoic halo is prominent
Chronic Phase
Injury more than 10 days
Dense granular material develops
encapsulating foreign body - Granuloma
Clean Shadow
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Shadowing
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Hypoechoic Rim
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Granuloma Formation
• <Insert Figure 26-12A-B>
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Appearance of Retained Foreign Bodies
1. Echogenic with clean shadowing
2. Echogenic with dirty shadowing
3. Echogenic with distal ring down
4. Echogenic with hypoechoic ring surrounding the object
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Sonogram of Foreign Body and Air
Mimicking Foreign Bodies
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Documenting Foreign Body Location
• <Insert Figure 26-15A-B>
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Sonography-Assisted Removal
• Forceps
Needle
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Limitations
• Varying imaging angles can decrease differentiation from
bone
• Wound exploration or irrigation may decrease air bubbles
in field of view
– Lidocaine injection
• False positives
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Summary
• The sonography examination relies on the skill,
knowledge, and accuracy of the sonographer who pays
attention to the composition, location, age, and artifacts
associated with foreign bodies.
• The experienced sonographer has an important role prior
to, during, and following sonography-guided foreign body
removal.
Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins
Summary
• Recognizing foreign body detection and removal is a
unique and evolving application of emergency
sonography.
• Sonography should become the main imaging tool used
for the detection and localization of soft tissue foreign
bodies because of its sensitivity, it is noninvasive, and it
provides a high-resolution, real time evaluation.
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