Initial Ultrasound for Meckel's Diverticulum and Duplication Cyst in Pediatric Patients: Diagnostic Performance, Limitations, and Pitfalls.

Purpose: To evaluate the diagnostic performance of ultrasound in detecting Meckel's diverticulum (MD) and duplication cysts (DC) and to identify factors influencing diagnostic accuracy.

Methods: Among 66 patients with MD or DCs, we assessed the effect of symptom presence, atypical complications (hemoperitoneum, perforation, or acute pancreatitis), and lesion shape (tubular or cystic) on initial sonographic diagnostic accuracy using Fisher's exact test.

Results: Initial ultrasound correctly diagnosed 49.9% (27/66) of cases. Correct diagnosis rates differed significantly between MD and DC (11/17 vs. 33/5, p < 0.001) and between tubular and cystic lesions (13/15 vs. 36/2, p < 0.001). No significant differences were observed for symptomatic versus asymptomatic cases (22/6 vs. 34/4, p = 0.302) or for cases with versus without atypical complications (1/27 vs. 5/33, p = 0.230). However, all DC cases with atypical complications were misdiagnosed on ultrasound.

Conclusion: Ultrasound demonstrated reliable diagnostic performance for DCs; however, MDs were more challenging to identify. Consequently, when MDs are suspected on clinical grounds, additional imaging, such as Tc-99m scintigraphy, should be considered. In patients with DCs, atypical complications, such as hemoperitoneum or acute pancreatitis, may obscure sonographic diagnosis. Sonographers should therefore include DCs in the differential diagnosis when these complications arise without an apparent etiology.