Chapter 26 Foreign Bodies

Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins

Chapter 26Foreign Bodies

Abdomen and Superficial Structures


ObjectivesObjectives

• 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.


ObjectivesObjectives

• 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.


Composition of Foreign BodiesComposition 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)


TransducerTransducer

• Large Footprint Screening

• 7-12 MHz

• High Resolution


Increasing Near Field LengthWater Bath Technique

Increasing Near Field LengthWater Bath Technique

• Increase visualization of skin surface.


Increasing Near Field LengthIncreasing Near Field Length


Edge Shadowing ArtifactsEdge Shadowing Artifacts


Speckle Reduction Imaging & Hyperemic Flow Inflammatory RxnSpeckle Reduction Imaging & Hyperemic Flow Inflammatory Rxn


Using Anatomy to Locate Foreign BodiesUsing Anatomy to Locate Foreign Bodies


Foreign Body LocationForeign Body Location


Age of the Foreign BodyAge of the Foreign Body

Acute Phase Injury less than 3 daysBright, Echogenic, ShadowingAfter 24 hours – hypoechoic halo develops (inflammatory rxn)

Intermediate Phase Injury within 3 to 10 daysAir replaced by fluid, No shadowing, Hypoechoic halo is prominent

Chronic Phase Injury more than 10 daysDense granular material develops encapsulating foreign body - GranulomaClean Shadow


ShadowingShadowing


Hypoechoic RimHypoechoic Rim


Granuloma FormationGranuloma Formation

• <Insert Figure 26-12A-B>


Appearance of Retained Foreign BodiesAppearance 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


Sonogram of Foreign Body and Air Mimicking Foreign BodiesSonogram of Foreign Body and Air Mimicking Foreign Bodies


Documenting Foreign Body LocationDocumenting Foreign Body Location

• <Insert Figure 26-15A-B>


Sonography-Assisted RemovalSonography-Assisted Removal

• Forceps Needle


LimitationsLimitations

• Varying imaging angles can decrease differentiation from bone

• Wound exploration or irrigation may decrease air bubbles in field of view

– Lidocaine injection

• False positives


SummarySummary

• 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.


SummarySummary

• 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.

Chapter 26 Foreign Bodies

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