Aluminum foreign bodies: do they show up on x-ray?

The objective of this study is to evaluate the utility of radiographs in the detection of aluminum foreign bodies (FB). Aluminum can tabs were placed at the upper esophagus/posterior pharyngeal area in ten randomly selected cadavers. Anterior-posterior (AP) and lateral (LAT) radiographies were performed before and after placement. Twenty sets of randomly ordered radiographs were assessed by two blinded radiologists for the presence of radio-opaque FB. For any positive reading on an AP or a LAT radiograph, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for radiologist A were 80, 90, 89, and 82%, respectively, and for radiologist B were 90, 100, 100, and 91%, respectively. These values were also calculated using only AP and LAT views. Aluminum FB can often be visualized on radiographs. The sensitivity of this method, however, is not adequate to completely rule out their presence. Additional testing in these cases is warranted. Conversely, a high PPV suggests that therapy based on this finding alone is a logical choice.