Purpose:To evaluate the diagnostic performance of abdominal radiography in the detection of illegal intracorporeal containers (hereafter, packets), with low-dose computed tomography (CT) as the reference standard.Materials and Methods:This study was approved by the institutional ethical review board, with written informed consent. From July 2007 to July 2010, 330 people (296 men, 34 women; mean age, 32 years [range, 18-55 years]) suspected of having ingested drug packets underwent supine abdominal radiography and low-dose CT. The presence or absence of packets at abdominal radiography was reported, with low-dose CT as the reference standard. The density and number of packets (≤12 or >12) at low-dose CT were recorded and analyzed to determine whether those variables influence interpretation of results at abdominal radiography.Results:Packets were detected at low-dose CT in 53 (16%) suspects. Sensitivity of abdominal radiography for depiction of packets was 0.77 (41 of 53), and specificity was 0.96 (267 of 277). The packets appeared isoattenuated to the bowel contents at low-dose CT in 16 (30%) of the 53 suspects with positive results. Nineteen (36%) of the 53 suspects with positive low-dose CT results had fewer than 12 packets. Packets that were isoattenuated at low-dose CT and a low number of packets (≤12) were both significantly associated with false-negative results at abdominal radiography (P = .004 and P = .016, respectively).Conclusion:Abdominal radiography is mainly limited by low sensitivity when compared with low-dose CT in the screening of people suspected of carrying drug packets. Low-dose CT is an effective imaging alternative to abdominal radiography.©RSNA, 2012.