I think there are 2 questions here:
1. I believe the spirit of the initial solicitation (correct me if wrong) was whether or not there is a requirement for plain films prior to US to evaluate for free air. (Our center does not have such a requirement.)
2. The other issue is that of diagnostic accuracy for plain films (2 or 3 views) when ileocolic intussusception is suspected. Others have mentioned some valuable literature on this topic...my 2 cents would be that, when the diagnosis is likely (speaking to pretest probability), most of us, I think, would order the ultrasound as the gold standard for diagnosis.
It's for the larger proportion of patients, in whom the diagnosis is one of many in the differential, for whom the pre-test probability of ileocolic intussusception is lower, that plain films may prove more helpful in excluding the diagnosis.
(reference for clinical risk stratification: http://www.ncbi.nlm.nih.gov/pubmed/22270504 )
For more information, send mail to [log in to unmask] with the message: info PED-EM-L
The URL for the PED-EM-L Web Page is: