Mateusz Gładysz FESSH prep

FESSH prep Imaging Radiopaque versus radiolucent materials, ultrasound after negative radiographs, pooled ultrasound accuracy, sonographic appearance, role of MRI and CT

Imaging of a suspected retained soft-tissue foreign body in the hand

Last reviewed v1.0

FESSH-062Imaging●○○ basic

Regarding imaging of a suspected retained soft-tissue foreign body in the hand:

  1. 1.MRI is the first-line imaging test for a suspected retained foreign body in the hand.

  2. 2.Plain radiographs reliably show glass, metal and gravel foreign bodies, but often fail to show wood or plastic.

  3. 3.When radiographs are normal, ultrasound adds little, because it detects essentially the same radiopaque materials as radiography.

  4. 4.In pooled clinical studies, ultrasound is highly specific but only moderately sensitive for retained soft-tissue foreign bodies, so a negative scan does not exclude one.

  5. 5.On ultrasound, a retained foreign body typically appears hypoechoic, without acoustic shadowing.

FESSH marking: +1 per correct statement, 0 for blank, −1 for incorrect. Click the same TRUE/FALSE button twice to clear it.

Question ID
FESSH-062
First published
Last reviewed
Version
v1.0
Answer key and explanations — open after answering

  1. 1. MRI is the first-line imaging test for a suspected retained foreign body in the hand.

    False

    Plain radiography is the first-line test, followed by ultrasound when the radiograph is negative; CT may be needed for deeper objects. MRI is most useful for showing soft-tissue and bone complications of a retained foreign body, of which infection is the most frequent.

    • Carneiro BC, Cruz IAN, Chemin RN, Rizzetto TA, Guimarães JB, Silva FD, et al.. Multimodality Imaging of Foreign Bodies: New Insights into Old Challenges. Radiographics. 2020;40(7):1965-1986. PMID 33136481
    • Donaldson JS. Radiographic imaging of foreign bodies in the hand. Hand Clin. 1991;7(1):125-34. PMID 2037630

  2. 2. Plain radiographs reliably show glass, metal and gravel foreign bodies, but often fail to show wood or plastic.

    True

    In Manthey's blinded soft-tissue model study, two-view radiography detected the foreign bodies generally regarded as radiopaque (gravel, glass, metal) 98% of the time and never detected wood, plastic or cactus spines. Radiography remains the first-line test, but a normal radiograph does not exclude a wooden or plastic foreign body; in a cadaveric hand, Reiner found computed radiography viewed on a workstation the preferred technique for detecting wood and plastic.

    • Manthey DE, Storrow AB, Milbourn JM, Wagner BJ. Ultrasound versus radiography in the detection of soft-tissue foreign bodies. Ann Emerg Med. 1996;28(1):7-9. PMID 8669741
    • Carneiro BC, Cruz IAN, Chemin RN, Rizzetto TA, Guimarães JB, Silva FD, et al.. Multimodality Imaging of Foreign Bodies: New Insights into Old Challenges. Radiographics. 2020;40(7):1965-1986. PMID 33136481
    • Reiner B, Siegel E, McLaurin T, Pomerantz S, Allman R, Hebel JR, et al.. Evaluation of soft-tissue foreign bodies: comparing conventional plain film radiography, computed radiography printed on film, and computed radiography displayed on a computer workstation. AJR Am J Roentgenol. 1996;167(1):141-4. PMID 8659358

  3. 3. When radiographs are normal, ultrasound adds little, because it detects essentially the same radiopaque materials as radiography.

    False

    Ultrasound can depict foreign bodies of all materials, including radiolucent wood and thorns. In Crawford's series of 39 patients with a suspected foreign body in the hand and negative radiographs, ultrasound correctly localised 19 of the 20 radiolucent foreign bodies (18 wood, 2 thorns) found at operation, which also helped the surgeon locate them.

    • Crawford R, Matheson AB. Clinical value of ultrasonography in the detection and removal of radiolucent foreign bodies. Injury. 1989;20(6):341-3. PMID 2697696
    • Del Cura JL, Aza I, Zabala RM, Sarabia M, Korta I. US-guided Localization and Removal of Soft-Tissue Foreign Bodies. Radiographics. 2020;40(4):1188-1195. PMID 32469630

  4. 4. In pooled clinical studies, ultrasound is highly specific but only moderately sensitive for retained soft-tissue foreign bodies, so a negative scan does not exclude one.

    True

    Davis's meta-analysis of 17 studies found a pooled sensitivity of 72% and specificity of 92%. The included studies were of low quality with high heterogeneity, so these estimates are imprecise.

    • Davis J, Czerniski B, Au A, Adhikari S, Farrell I, Fields JM. Diagnostic Accuracy of Ultrasonography in Retained Soft Tissue Foreign Bodies: A Systematic Review and Meta-analysis. Acad Emerg Med. 2015;22(7):777-87. PMID 26111545

  5. 5. On ultrasound, a retained foreign body typically appears hypoechoic, without acoustic shadowing.

    False

    Del Cura and colleagues note that, although the appearance varies with the material and shape, all foreign bodies are echogenic and frequently show posterior acoustic shadowing or reverberation artefact. Ultrasound can also guide percutaneous removal through a small incision.

    • Del Cura JL, Aza I, Zabala RM, Sarabia M, Korta I. US-guided Localization and Removal of Soft-Tissue Foreign Bodies. Radiographics. 2020;40(4):1188-1195. PMID 32469630