Radiographic evaluation of intussusception: Utility of left-side-down decubitus view

Purpose: To assess the incremental value of the left-side-down decubitus view in radiographic evaluation of ileocolic intussusception. Materials and Methods: The institutional review board approved this retrospective investigation with waiver of informed consent. Between February 24, 2002, and January 25, 2007, 304 studies (300 patients; mean age, 1.3 years; range, 0.1-3.9 years) met the following inclusion criteria: kidney ureter bladder (KUB) and decubitus views obtained, with subsequent proof of diagnosis. Using a consensus approach, two pediatric radiologists evaluated KUB and decubitus views for four variables: (a) discrete mass and (b) small-bowel obstruction (positive criteria); (c) air or stool in ascending colon and (d) cecal air or stool (negative criteria). On the basis of these criteria, each study was graded as negative, positive, or indeterminate for intussusception. Diagnostically determinate studies and the ability to visualize or exclude intussusception were calculated to determine sensitivity and specificity. The difference between proportions was calculated, along with 95% confidence intervals. Agreement between the supine KUB view and supine KUB plus left-side-down decubitus views was tested with the McNemar test. Results: Intussusception was present in 58 of 304 studies (19%). Adding the decubitus view to the KUB view increased the number of determinate studies from 110 of 304 (36.2%) to 205 of 304 (67.4%) (difference, 31.2 percentage points; P < .001). Intussusception was correctly identified with KUB view alone in 35 of 58 studies (60.3%); this value increased to 43 of 58 (74.1%) with KUB plus decubitus views (P = .0215). Intussusception was correctly excluded with the KUB view alone in 63 of 246 studies (25.6%); this increased to 143 of 246 studies (58.1%) with addition of the decubitus view (P < .0001). Conclusion: The addition of decubitus views increased the number of diagnostically determinate studies and increased the ability to diagnose or exclude intussusception. The authors believe that a left-side-down decubitus view should be included in the initial evaluation of patients suspected of having intussusception, particularly when the supine view is diagnostically indeterminate. (C) RSNA, 2008.