Foreign Bodies

Published on 19/07/2015 by admin

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Last modified 22/04/2025

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 Commonly affect children, developmentally challenged or psychiatric patients, and inebriated adults

image Most ingested foreign bodies traverse GI tract without problem: < 1% cause obstruction or perforation

– Elongated or sharp objects may impact at point of intestinal narrowing or sharp angulation
image Foreign bodies vary in radiopacity and conspicuity on radiography vs. CT
image For most nonsharp foreign bodies, begin with visual inspection of oropharynx and plain radiographs
image For sharp objects at risk of complications, start with CT

– Avoid administering enteric contrast material; makes subsequent endoscopy more difficult
– IV contrast administration preferable to better evaluate potential complications
• Inserted foreign bodies

image Rectum, vagina, and urethra are common sites
image Objects may be inserted during sexual practice, as a result of an assault, or to hide drugs
image Perforation of rectosigmoid colon may occur with original insertion or during attempted removal
• Retained surgical items

image Most common in abdominal surgery (especially emergent)
image Crucial to distinguish intentional or expected objects from unintended

– Common intentional devices: Surgical drains, rubber retention sutures, metallic clips for wound closure, hemoclips, or intraarterial, intravenous, and intraintestinal catheters
image Most commonly woven cotton surgical sponge

– Most have radiopaque stripe interwoven into fabric or as attached strip of cloth
– Cotton fabric is invisible on radiographs but seen as swirled gas or soft tissue on CT scans
– Gossypiboma:Foreign body reaction to cotton fabric of sponge or towel producing inflammatory mass with sponge at center

image Produces variable degree of inflammation, fibrosis, retraction, and adhesion to adjacent abdominal structures
image Low-density heterogeneous mass with wavy, spongiform pattern and internal linear high density (representing the sponge itself)
• Intentionally retained surgical material

image Oxidized regenerated cellulose (Gelfoam/Surgicel) deliberately left in place after surgery for hemostasis
image Usually absorbed within 7-14 days
image Tightly packed, swirled, or linear gas on CT 

– May be mistaken for abscess but contains very little fluid and never shows air-fluid level
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(Left) Plain film shows the appearance of a standard cylindrical-shaped battery image after ingestion. Swallowing batteries is relatively common and can cause bowel perforation or obstruction as the acid in the battery may leak out.

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(Right) Axial CECT in a patient with a retained surgical sponge demonstrates the characteristic CT appearance of a chronic gossypiboma image. Note the wavy, serpiginous pattern within the mass and the well-defined wall.
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(Left) Axial T2 MR in the same patient demonstrates the characteristic MR appearance of a gossypiboma image, with wavy, high T2 signal and a well-defined T2-hypointense wall.

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(Right) Transverse grayscale US in the same patient demonstrates a very similar appearance to the MR and CT images, with a well-defined mass image and internal alternating bands of hyper- and hypoechogenicity. Some of the hyperechoic bands with posterior acoustic shadowing image may reflect gas within the mass.

TERMINOLOGY

Abbreviations

• Foreign body (FB)

Definitions

• Ingestion or insertion of potentially injurious foreign objects into any site within body

IMAGING

General Features

• Best diagnostic clue

image Radiopaque or radiolucent object on plain film or CT with characteristic appearance of common FBs
• Location

image Gastrointestinal (GI) or genitourinary tract, peritoneal cavity, abdominal wall

Imaging Recommendations

• Best imaging tool

image Plain radiograph or CT

Ingested Foreign Bodies

• Commonly affected patient groups

image Children (vast majority of foreign body ingestions)

– Peak incidence between 6 months and 6 years of age
– Often swallow coins, toys, or virtually anything else
image Developmentally challenged or psychiatric patients

– Common items include jewelry, batteries, silverware
image Prisoners and future prisoners

– Razor blades (often covered in radiolucent tape to gain entry to hospital), drug packets
image Edentulous, elderly, or inebriated adults

– May swallow bones, toothpicks (common in martini drinkers), plastic tops of medication bottles, etc.
– Food bolus impaction more common in edentulous older patients (often with esophageal pathology)
• General principles

image Most ingested FBs traverse GI tract without problem

– < 1% cause obstruction or perforation of GI tract
– Need for intervention may be higher with intentional ingestions (surgery required in 12-16%)
– Overall mortality rate is very low
image Distinguish accidental or intentional foreign body ingestion from ingestion of diagnostic devices

– pH meter capsule, capsule endoscopy, and migrated biliary/pancreatic duct stents can be confusing without clinical history
image Elongated or sharp objects may impact at point of intestinal narrowing or sharp angulation

– (e.g., pylorus, duodenum, ileocecal valve, site of bowel stricture or adhesion)

image Perforations are most common near ileocecal valve
– Long pointed objects (toothpick, needle) may lodge in and perforate appendix or Meckel diverticulum

image Perforation may be incomplete or fail to present with acute symptoms; many are discovered weeks to years later
image Common ingested foreign bodies and management

– Most small objects < 2.5 cm in size (i.e., coins) are likely to pass on their own

image Coins account for > 3/4 of foreign body ingestions in children
image Coins may obstruct in esophagus
– Longer objects > 6 cm in length (eating utensils, toothbrushes) are unlikely to traverse duodenum and should be retrieved endoscopically
– Ingested disk (e.g., watch) batteries are caustic

image Should be removed from esophagus or stomach if possible
image Often can retrieve from esophagus with balloon-tipped rubber catheter, magnet, or endoscope
– Sharp pointed objects (chicken/fish bones, paperclips, toothpicks, needles, etc.) have high risk of complications (1/3 of patients)

image Should be endoscopically retrieved if in duodenum or stomach
image Follow-up with radiographs if more distal
image Surgery possible if FB fails to pass or complications
– Magnets

image Can cause severe injury if multiple magnets are ingested, trapping bowel loops between 2 magnets’ attractive force
image Can lead to bowel wall necrosis, fistulas, bowel obstruction, etc.
image All magnets should be retrieved immediately
image Foreign bodies vary in radiopacity and conspicuity on radiography vs. CT

– Plastic and thin aluminum (e.g., pull tabs from cans) are radiolucent
– Chicken and meat bones are opaque
– Fish bones are often lucent on plain films, opaque on CT
– Glass is always radiopaque, but very small slivers may not be detectable
– Coins, except for Italian lira, are opaque
– Wood is radiolucent (closer to air than soft tissue density)
– Medication pills and capsules are variably opaque

image e.g., iron pills, Pepto-Bismol, phenothiazine, many enteric-coated pills
– Cocaine or heroin packets are variably opaque; usually wrapped in condoms or balloons and swallowed or inserted into rectum or vagina

image May be visible as crescent of air density between 2 layers of wrapping surrounding drugs; double condom sign
image May appear as well-defined round objects in bowel (of variable attenuation depending on type of drug)
image Examine entire GI tract for additional FBs

– For most nonsharp foreign bodies, begin with visual inspection of oropharynx and plain radiographs
– For sharp objects at high risk of complications, start with CT

image Avoid administering enteric contrast material; coating of bowel with contrast may make subsequent endoscopic retrieval more difficult
image IV contrast administration is preferable to better evaluate potential complications
– Many patients are repeat offenders and may have swallowed several objects at different times

Inserted Foreign Bodies

• Any orifice may be involved; rectum, vagina, and urethra are common sites
• Objects may be inserted during sexual practice, as a result of an assault, to hide drugs and other illegal paraphernalia, or even sharp objects/weapons in prison setting

image Majority of foreign bodies do not cause significant injury
image Perforation of rectosigmoid colon may occur with original insertion or during attempted removal

– Consider contrast enema for diagnosis of perforation
image Approach to removal (i.e., manual, endoscopic, surgical) will depend on type of FB, symptoms, perforation, etc.
image Rectal or vaginal FBs are often various cylindrical objects that become stuck within organ
• Some rectal or vaginal FBs are result of prior medical interventions

image e.g., thermometers, enema tips and covers, suppository wrappers, and medications intended for oral use
• Any FB remaining in place within bladder or vagina will become encrusted with mineral salts, becoming progressively larger and more opaque

image Bladder calculus of unusual shape, or in a child, is likely encrusted FB
• Body piercing (labia, penis, etc.) may mimic intraluminal FB

Retained Surgical Items

• Occurs in roughly 1/18,000 inpatient surgeries, but more common in abdomen (1/1,000-1,500 laparotomies)

image Particularly common in setting of emergency surgery
image May be immediately symptomatic but can persist unnoticed for months or even years
• Crucial to distinguish intentional or expected objects from unintended

image Common intentional devices: Surgical drains, rubber retention sutures, metallic clips for wound closure, hemoclips, or intraarterial, intravenous, and intraintestinal catheters
image Most common unintentional retained foreign body is woven cotton surgical sponge

– Suggested by incorrect sponge count, although sponge counts are notoriously inaccurate
image Retained needles or surgical instruments

– Generally easy to recognize but may be misinterpreted as lying outside of patient
• Identification of retained surgical sponges or towels on imaging

image Most have radiopaque stripe interwoven into fabric or as attached strip of cloth

– Identified as curvilinear radiopaque line on radiographs or CT
image Cotton fabric is invisible on radiographs but seen as swirled gas or soft tissue on CT scans

– May recognize folded cloth pattern on CT or MR
– T2WI MR especially good at depicting folded or swirled cloth pattern within encapsulated fluid collection
image Gossypiboma:Foreign body reaction to cotton fabric of sponge or towel left inside patient produces inflammatory mass with sponge at center

– Produces variable degree of inflammation, fibrosis, and adhesions to adjacent abdominal structures
– May cause fistula between bowel segments or to other viscera
– Low-density heterogeneous mass with wavy, spongiform pattern, internal linear high density (representing sponge itself), and well-defined wall

image Rarely calcifications in wall in chronic setting
– May be difficult to distinguish from abscess (and foreign body reaction may lead to formation of frank abscess)

Intentionally Retained Surgical Material

• Oxidized regenerated cellulose (Gelfoam or Surgicel)

image Bioabsorbable sterile knitted fabric deliberately left in place within surgical bed at end of procedure to produce hemostasis
image Upon contact with blood, the fabric induces rapid hemostasis by inducing thrombus formation, and swells into gelatinous mass, trapping air (gas) within its interstices
image Usually absorbed within 7-14 days
image Has radiographic and CT appearance of tightly packed, swirled, or linear gas bubbles without much fluid content

– Usual appearance of soft tissue density mass surrounding gas collections
– May be mistaken for abscess, but contains very little fluid and never shows air-fluid level

image Check operative note or discuss with surgeon: Correlate with surgical placement of oxidized cellulose
– Presence of hemostatic sponge does not prevent formation of abscess

image Presence of larger loculated collection of fluid or air-fluid level suggests abscess
image Ultrasound: Echogenic mass with posterior reverberation artifact (indicating gas content) ± surrounding fluid
image MR: Low signal on T2 due to predominance of gas over fluid

– Unlike abscesses, which demonstrate high T2 signal

DIAGNOSTIC CHECKLIST

Consider

• Expect to find multiple ingested or inserted FBs: Do not stop searching after locating 1st FB

image Examine entire neck, chest, abdomen, and pelvis in cases of ingested FBs
• Distinguish deliberately placed hemostatic material (e.g., oxidized cellulose) from retained surgical sponge or abscess

image Call surgeon or read operative note to determine whether Surgicel was used for hemostasis

Image Interpretation Pearls

• In postoperative patient when evaluating for retained FB, ensure that entire operative field is included within field of view

image Manipulate contrast level and width to optimize visualization
image CT: Utilize scout radiograph, axial sections, and multiplanar reformations to best appreciate shape and nature of FB and distinguish from contrast in bowel
• Distinguish between “expected” and “unexpected” FBs

image e.g., feeding tubes, surgical clips vs. needles, drains vs. surgical sponges

Reporting Tips

• Immediately call referring clinician or operating room if foreign body is detected or suspected

image
(Left) Axial CECT in a patient with a long psychiatric history demonstrates a linear metallic foreign body image in the small bowel, perforating the small bowel and extending into the abdominal wall.
image
(Right) Coronal volume-rendered CECT better demonstrates that the patient has ingested many different pins and paper clips. The patient had a long history of ingesting pins and had to be taken to surgery to remove the foreign bodies.
image
(Left) Axial NECT shows portions of a foreign object image within the bladder. The object turned out to be a penlight which was subsequently retrieved in the cystoscopy suite.

image
(Right) Frontal radiograph in a patient with rectal pain shows a faintly opaque cylindrical object image in the expected position of the rectum. Under general anesthesia the plastic dildo was retrieved.
image
(Left) Axial CECT in a patient who had unintentionally swallowed a metallic clip demonstrates that the clip image has caused an inflammatory stricture image of the adjacent small bowel, which is thickened with mucosal hyperemia.

image
(Right) Frontal image from a small bowel follow-through demonstrates a filling defect image corresponding to the clip seen on CT. Note that the stricture image in the immediately distal small bowel is causing mild obstruction of the dilated image proximal bowel.

image
(Left) Coronal CT scout view demonstrates a wavy radiopaque band image in the pelvis, typical of a retained surgical sponge. This radiopaque tag can be directly woven into the sponge or can be attached to it.
image
(Right) Axial CECT in the same patient demonstrates an inflammatory gas and fluid-containing mass image forming around the retained sponge, characteristic of a gossypiboma.
image
(Left) Axial CECT in an elderly man with pain following aortic bypass surgery shows a large mass, a gossypiboma image consisting of swirled gas and soft tissue density, that was found to represent a surgical towel that had been left in the peritoneal cavity. Note the absence of a radiopaque marker.

image
(Right) Axial CECT in a patient who had recently undergone surgery demonstrates a fluid collection image with a well-defined wall and multiple foci of internal gas. Notice the radiopaque foreign body image within the collection.
image
(Left) Coronal CECT in the same patient nicely demonstrates the full extent of the bilobed fluid collection image, and once again demonstrates the linear, band-like foreign body image within the collection.

image
(Right) Coronal volume-rendered CECT in the same patient demonstrates that the radiopaque foreign body visualized previously was the radiopaque band image incorporated into a surgical sponge. Also note the presence of a plastic ring image within the abdomen connected to the surgical sponge.

image
(Left) Radiograph in a young man who stabbed himself in the abdomen with a ballpoint pen shows the faint outline of the plastic pen image and its metal tip image.
image
(Right) Lateral spot film from a small bowel follow-through in the same patient shows a segment of small bowel that is tethered to the anterior abdominal wall image with extravasation of barium into a bag image overlying the anterior abdominal wall wound. At surgery, small bowel perforation was confirmed, and a plastic Bic pen was retrieved.
image
(Left) Axial CECT in a patient with abdominal pain and fever after cholecystectomy shows a collection of gas image but little fluid in the cholecystectomy bed, mimicking an abscess. Note the adjacent surgical clips image.

image
(Right) Axial CECT in the same patient shows the gas collection image, which represents retained Surgicel (oxidized cellulose), placed to control continued oozing of blood. It may be impossible to distinguish this from an abscess without the proper history, and in such cases, needle aspiration may be required.
image
(Left) Axial NECT in a patient with fever and pain following partial left nephrectomy shows a collection of gas and soft tissue density image in the perirenal space. This represents Surgicel, not an abscess. Note the surgical clip image at the site of resection.

image
(Right) Axial CECT in a patient with a postoperative abscess following partial colectomy shows a collection of gas representing Surgicel image, surrounded by a large collection of fluid with an enhancing capsule image, typical for an abscess.
image
A digital CT scout radiograph shows a curvilinear radiopaque stripe image within the right side of the abdomen.

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Axial CECT in the same patient shows surgical absence of the right kidney. There is an oval, encapsulated, heterogeneous collection of fluid and gas density image within the right side of the abdomen. Immediately adjacent to the encapsulated fluid collection is a thin, radiopaque structure image that corresponds to the structure seen on the radiograph. This is a classic appearance of a gossypiboma, a retained surgical sponge that has resulted in a chronic abscess or foreign body reaction.
image
AP radiograph shows a faintly opaque cylindrical object image in the expected position of the rectum. Following retrieval under anesthesia, consideration should be given to perform a contrast enema to exclude foreign body perforation of the rectum, which is a fairly common occurrence in this setting.
image
Axial NECT shows portions of a foreign object image within the prostate.
image
Volume-rendered CT shows the position of the foreign body image, which turned out to be a penlight, relative to the bony structures of the pelvis. The object was retrieved in the cystoscopy suite.
image
Axial NECT shows a faintly radiopaque and curved fish bone image that is embedded within the wall of the stomach. This would not be evident on plain radiography due to its small size and minimal calcification. It is unusual for a fish bone to become embedded in the stomach; some penetrate the mucosa of the pyriform sinus, whereas most merely scratch the surface and do not become impaled.
image
Axial CECT shows a thick-walled segment of ileum image with infiltration of the adjacent mesenteric fat. There is a thin calcific density image within the wall of the bowel.
image
Axial CECT in the same patient again shows an internal calcified linear density image. At surgery, a chicken bone was found to have perforated the distal ileum. Physiological points of narrowing, especially the distal ileum, are common sites of obstruction or perforation by ingested foreign bodies.
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AP radiograph demonstrates the standard appearance of the probe image in capsule endoscopy. This is an intentional foreign body, which should not be misinterpreted as an object of concern.
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AP radiograph demonstrates several expected foreign bodies, including nephrostomy catheters image, midline skin clips image, and surgical drains image. It might be easy to overlook the retained surgical sponge image that required opening the incision and retrieval.
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Axial CECT shows a collection of gas and fluid image in the right lower quadrant near the ileocecal valve. There is extrinsic compression and wall thickening of the terminal ileum and colon. At surgery a toothpick was found to have perforated the terminal ileum.
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Frontal radiograph in a 34-year-old woman with urinary infection and flank pain shows a ureteral stent image and stones in the lower pole of the kidney image and in the bladder around the distal part of the stent image.
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Axial NECT in the same patient shows the stone image that has formed around the stent. Ureteral and biliary stents that remain in place for a long time invariably become encrusted with mineral salts, with luminal obstruction and formation of calculi within and around the stents.
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Frontal radiograph in a 36-year-old woman with Crohn disease shows a ring image in the lower abdomen that had been swallowed by the patient for unknown reasons. She subsequently developed acute abdominal pain.
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Frontal radiograph in a 35-year-old man with pain following renal transplant shows a curvilinear radiopacity in the pelvis image that represents a retained lap pad from the transplant procedure.

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