W92 AJR:203, July 2014 entity among radiologists is important and can result in earlier diagnosis, facilitating timely interdisciplinary management of the patient. Another known nonaccidental cause of for- eign bodies of the musculoskeletal system is acupuncture needles [8–12]. The issues pertaining to foreign bodies of the musculoskeletal system that go unno- ticed are often underestimated. Indeed, mal- practice lawsuits against emergency physi- cians in this setting result in the fifth highest amount of indemnity awards paid to patients [13]. More than one third of foreign bodies of the musculoskeletal system are missed in the initial clinical examination, most frequent- ly because no imaging examination is per- formed at the time of the examination [1]. A lack of clear guidance on the role of different imaging modalities in a suspected foreign body can make the management algorithm unclear to both referring physicians and ra- diologists. The purpose of this article is to clarify the most relevant points in the man- agement of suspected retained foreign bodies of the musculoskeletal system on the basis of literature review and published reports and to present cases to illustrate each type of for- eign body of the musculoskeletal system on radiography, ultrasound, CT, and MRI. Pathologic Process Associated With Foreign Bodies of the Musculoskeletal System After a penetrating skin injury, the pres- ence of a retained object within the soft tis- sue will trigger a granulomatous reaction consisting of histiocytes, fibroblasts, and Multimodality Imaging of Foreign Bodies of the Musculoskeletal System Mohamed Jarraya 1 Daichi Hayashi 1 Richard V. de Villiers 2 Frank W. Roemer 1,3 Akira M. Murakami 1 Alda Cossi 1 Ali Guermazi 1 Jarraya M, Hayashi D, de Villiers RV, et al. 1 Department of Radiology, Section of Musculoskeletal Radiology, Boston University School of Medicine, 820 Harrison Ave, FGH Bldg 3rd Fl, Boston, MA 02118. Address correspondence to A. Guermazi (guermazi@bu.edu). 2 Drs. Van Wageningen and Partners, Somerset West, South Africa. 3 Department of Radiology, University of Erlangen, Erlangen, Germany. Musculoskeletal Imaging • Review F oreign objects embedded in the body through penetrating injury are a common problem in emer- gency departments. In this article we are concerned specifically with foreign bodies of the musculoskeletal system. The foreign object is often wood, glass, or metal, and bullets are not rare. The incident in which the penetration occurs may be painful and re- quire immediate action; on the other hand, the initial penetration may be painless and may not even be noticed by the patient. Some foreign bodies may go unnoticed for days or even decades before they become a problem [1]. One in four patients with a retained for- eign body of the musculoskeletal system ini- tially presents with a complication [1], which is most commonly infection but can also be the result of neurovascular or tendinous inju- ries [1, 2] or an excessive granulomatous re- action around the retained object [3, 4]. Rare- ly, foreign bodies of the musculoskeletal system are found incidentally while evaluat- ing another problem. Aside from accidental insertion, foreign bodies of the musculoskeletal system may also result from self-embedding behavior, which is a recently documented entity in the pediatric medical literature [5, 6]. Although frequent- ly misdiagnosed, ignored, or underreported, self-embedding behavior is an extreme form of self-injury in which inanimate objects are intentionally inserted into soft tissues, un- der skin, or even into muscle [6, 7]. Patients who show self-embedding behavior are most- ly white teenage female patients with multiple psychiatric diagnoses [5, 7]. Awareness of this Keywords: CT, glass, metal, MRI, musculoskeletal foreign bodies, ultrasound, wood DOI:10.2214/AJR.13.11743 Received August 2, 2013; accepted after revision October 16, 2013. F. W. Roemer is a stock holder of Boston Imaging Core Laboratory and is a consultant to MerckSerono and the National Institutes of Health. A. Guermazi is the president of Boston Imaging Core Laboratory and is a consultant to Genzyme, MerckSerono, and TissueGene. Supplemental Data Available online at www.ajronline.org. WEB This is a web exclusive article. AJR 2014; 203:W92–W102 0361–803X/14/2031–W92 © American Roentgen Ray Society OBJECTIVE. The purpose of this article is to clarify the most relevant points in man- aging suspected foreign bodies of the musculoskeletal system on the basis of a literature re- view and published reports with cases to illustrate each type on different imaging modalities. CONCLUSION. Foreign bodies of the musculoskeletal system are a common problem in emergency departments, with more than a third missed in the initial clinical evaluation. These retained objects may result in various complications and also offer fertile ground for litigation. Jarraya et al. Imaging of Foreign Bodies of the Musculoskeletal System Musculoskeletal Imaging Review Downloaded from www.ajronline.org by Boston Univ Med Libr on 06/26/14 from IP address 168.122.67.91. Copyright ARRS. For personal use only; all rights reserved