Fluoroscopic criteria for on-site evaluation of failed intussusception reduction during air enema technique.

Background: There is no reliable fluoroscopic criteria for failed intussusception reduction during air enema technique.
Methods: This retrospective case-control study included 373 episodes of ileocolic intussusceptions who had undergone air enema under fluoroscopy. All procedures were initially classified by conventional fluoroscopic criteria: presumptive successful procedures (PSP) vs. presumptive failed procedures (PFP). PFP were divided into true failure, false failure, and undetermined groups. The configuration and size of the residual mass were evaluated on fluoroscopic images. Statistical analyses included Mann-Whitney U-test, Fisher's exact test, receiver operating characteristic (ROC) analysis, logistic regression analyses, and Kruskal-Wallis rank sum test with a post hoc Tukey test.
Results: PSP was 264 episodes (71%) and PFP was 109 episodes (29%). The true failure was 40 (37%) and false failure was 48 (44%). The true failure group commonly showed a larger size and round configuration for the residual mass than false failure (P<0.001). Multivariable analysis revealed configuration (P=0.004) and transverse diameter (P=0.007) as significant parameters that differentiated true and false failure. The optimal cut-off value of the transverse diameter of the residual mass was 2.3 cm. The sensitivity and specificity of conventional fluoroscopic criteria for failed reduction was 100% and 85%, respectively. The combination of new fluoroscopic findings and conventional criteria increased the specificity to 100%. Conclusions: Fluoroscopic finding of round-shape and larger size residual mass combined with conventional criteria may be useful for differentiating false failure from truly failed enema reduction in children with intussusception. 2022 Quantitative Imaging in Medicine and Surgery. All rights reserved.