what does a aluminium fragment/ring pull look like on CT?
what would happen if the patient had a MRI scan?
From: John Ryan [mailto:[log in to unmask]]
Sent: Wednesday, April 17, 2002 21:09
To: [log in to unmask]
Subject: Re: Swallowed FB was: Being over-riden by radiographers
Does anyone remember these 2 papers about aluminum and the gut. Remember it
is not radio-opaque....
1) Using a metal detector to locate a swallowed ring pull.
Ryan J, Perez-Avila CA, Cherukuri A, Tidey B. J Accid Emerg Med 1995
Accident and Emergency Department, Royal Sussex County Hospital, Brighton.
A 48-year-old man accidently swallowed the ring pull from a soft drink can.
He complained of pain in his chest. Chest radiographs were normal. A metal
detector emitted a strong response when passed across the front of his
chest. Oesophagoscopy was carried out and the ring pull was successfully
removed. We recommend the wider use of metal detectors by accident and
emergency (A&E) department staff particularly when dealing with patients who
have ingested metals of low radiodensity.
2) Radiographs and aluminium: a pitfall for the unwary
D M Bradburn, : BMJ 1994 May 7;308(6938):
Departments of Surgery and Radiology, Middlesbrough General Hospital,
Middlesbrough, Cleveland TS5 5AZ
Ingestion of radio-opaque foreign bodies is common. We highlight the need
for a careful radiological examination and endoscopy if symptoms of
A 70 year old man presented to the local hospital while on holiday, having
accidentally swallowed part of the metallic tab of a soft drinks can. He
complained of retrosternal discomfort and pain on swallowing. Plain
radiographs of the chest and neck showed no foreign body and he was
On returning home he consulted his general practitioner, who referred him to
another accident and emergency department, where plain radiographs again
showed no abnormality. After four months of persistent retrosternal
discomfort and progressive dysphagla he was referred for endoscopy, which
showed a malignant looking ulcer 22 cm from the incisors. Biopsy showed no
evidence of malignancy, and five further endoscopies over the subsequent
three months confirmed a progressive, clinically malignant, stricture,
although results on biopsy, oesophageal brushing, and needle cytology did
not show any malignancy. A barium swallow examination showed the typical
shouldered appearance of a malignant stricture (figure), and computed
tomography showed a mass consistent with an oesophageal carcinoma. A small
linear opacity was noted in the stricture in one image only, but this was
thought to be indistinguishable from oral contrast medium.
In view of his progressive dysphagia a three stage oesophagogastrectomy was
performed. There was a hard thickening in the oesophagus, with a surrounding
soft swelling and two adjacent lymph nodes. Subsequent pathological
examination of the specimen showed an oesophageal diverticulum containing
part of a tab of a soft drinks can. There was no evidence of malignancy.
Patients commonly attend accident and emergency departments because they
have swallowed a foreign body, but the problems they experience are few as
most objects pass through the gastrointestinal tract without incident.1
Impaction in the oesophagus is, however, serious and may result in
perforation and even death if missed. Items of food are the commonest
foreign bodies in adults, while shiny objects, such as coins, are commoner
in children.1 Tabs of soft drink cans are unusual foreign bodies, having
been reported in children2 but not, to our knowledge, in adults.
Oesophageal impaction may be suspected clinically from dysphagia and
retrosternal discomfort, and initial management should include inspection of
the oropharynx and radiography of the neck and chest if the foreign body is
thought to be radio-opaque. A delay in diagnosis may result in an abscess,
strictures, perforation, or even death, and our case shows that normal
results in a chest radiograph cannot be considered adequate to exclude
oesophageal impaction of an aluminium foreign body.3,4 Aluminium has a low
radiodensity, but this fact was not widely known in a straw poll among our
The minimal thickness of steel detectable in vivo is 0.12 mm, and aluminium
is 10 times less absorptive. The average thickness of an aluminium ring pull
is 0.35 mm, so it is unlikely to be detected in a face on projection.
Anteroposterior and lateral projections have therefore been advocated.3 If
symptoms persist but no foreign body has been identified endoscopy should be
a manadatory part of the investigation.