Accuracy of Plain Abdominal Radiography in the Differentiation between Small Bowel Obstruction and Small Bowel Ileus in Acute Abdomen Presenting to Emergency Department

Introduction Our purpose was to evaluate whether plain abdominal radiography (PAR) could accurately differentiate between small bowel obstruction (SBO) and small bowel ileus (SBI) in an emergency setting. We also evaluated the value of known classic signs on the PAR for differentiating between SBO and SBI. Methods This retrospective study included 216 emergency room patients who had small bowel distension (maximal small bowel diameter ≥2.5 cm) on the PAR and who underwent successive abdominal computed tomography. One radiologist and one emergency physician retrospectively reviewed PAR in consensus, unaware of the patients' clinical data; they divided the patients into an SBO group and an SBI group according to the radiographic findings. Presence or numeric values of 10 radiographic signs were also recorded. Final diagnoses of SBO and SBI were established by a combined analysis of medical charts, surgical records, radiographic findings on abdominal computed tomography, and small bowel studies. The differential diagnoses based on PAR and the final diagnoses were compared, and the sensitivity and specificity of PAR were calculated. We also evaluated the differences among 10 radiographic signs between the final SBO and SBI groups. Results Sensitivity and specificity of PAR for SBO were 82.0% and 92.4%, respectively. Among the 10 radiographic signs, all except maximal colon diameter were statistically significant predictors on the final diagnosis. Conclusions PAR is an accurate and effective initial imaging modality for differentiating between SBO and SBI in an emergency setting, and most of the classic radiographic signs have a diagnostic value.