Omental infarction is a benign self-limited disease that can mimic acute abdomen. The diagnosis can be established preoperatively with sonography and CT, which may avoid unnecessary laparotomy.

Objective. The aim of this study was to examine to what extent findings on ultrasonography performed in the emergency department (ED) after hours confirm or alter the referral diagnosis in patients without trauma as reflected in the discharge diagnosis. Methods. In this prospective study, data from 136 ultrasonographic examinations performed in patients without trauma after hours in the ED during January and February 2002 were evaluated against the suspected preimaging diagnosis of the referring ED physician and the actual discharge diagnosis from the ED or after hospitalization. The rate of preimaging and postimaging concordance was statistically analyzed and compared by calculation of confidence intervals and by the McNemar test. Results. Normal ultrasonographic findings were documented in 54 patients (40%), and pathologic findings were documented in 82 (60%). Thirty-four (25%) of the 136 examinations were concordant with the initial referring physician's diagnosis. Of the 102 studies that were not concordant with the initial referral suspected diagnoses, that is, being either a study with normal findings or offering an alternative diagnosis, 81 (79.4%) were concordant with the discharge diagnosis. Conclusions. After-hours ultrasonographic findings in patients without trauma seen in the ED seem to have a high impact on the discharge diagnosis and are concordant with it in more than 80% of cases.