Handheld metal detector versus conventional chest and abdominal plain radiography in children with suspected metallic foreign body ingestion: can we safely abandon X-rays?

Background: Ingestion of metallic foreign bodies (MFBs) is a frequent occurrence in children and is commonly diagnosed via X-rays. In recent years, the handheld metal detector (HMD) has been increasingly adopted by several pediatric hospitals as it is considered an effective and accurate diagnostic tool that avoids exposure to ionizing radiations. Sensitivity of HMD has been reported high (99.4%) in case of coin ingestion, but significantly lower (46%) when considering the ingestion of other types of MFBs.

Methods: We tested the effectiveness of the HMD in diagnosing ingested MFBs in children less than 14 years of age, in our Pediatric Emergency Department (PED). We prospectively evaluated all cases of MFBs ingestion that presented at the PED of our hospital from March 2015 to July 2017.

Results: Ninety-eight patients were included. The overall sensitivity was 63.2% (79.5% for coins, 25.5% for batteries and 56% for other objects) while the specificity was 95%. The HMD could have replaced the X-ray examination only if a MFB was detected below the xyphoid process.

Conclusions: Based on our findings, a negative result of HMD is not sufficient to exclude an ingestion of MFBs. Therefore, in case of an evocative history and depending on type and size of the foreign body, a radiological investigation is still necessary.