Detection rate of lymphoscintigraphy with technetium-99 m for pediatric chylopericardium

Lymphoscintigraphy has been used to diagnose chylopericardium; however, systematic studies on its detection rate for pediatric patients are lacking. We assessed the detection rate of lymphoscintigraphy with technetium-99 m for chylopericardium in pediatric patients and the factors affecting its diagnostic accuracy.

Ten patients diagnosed with chylopericardium based on pericardiocentesis who underwent lymphoscintigraphy were included in this retrospective study. The diagnosis of chylopericardium was established by consensus among pediatric surgeons, cardiologists, and physicians based on the clinical course, including the etiology of pericardial effusion and reaction to treatment, appearance of chylopericardium, and the level of triglyceride in the pericardium. The presence or absence of tracer accumulation in the pericardium was determined on images obtained 45 min and 2 h post-injection. A negative lymphoscintigraphy result was defined as the absence of accumulation on both images. Several factors were compared between positive and negative result groups using Fisher's exact test and Mann-Whitney U test: age; cardiac surgery; presence of a drainage tube within the pericardium at scintigraphy; pericardial fluid triglyceride level; and occurrence of chylothorax, liver uptake, and dermal backflow.

Among the 10 patients with chylopericardium, six had a positive lymphoscintigraphy result. The detection rate was 30.0% (3/10) and 60.0% (6/10) at 45 min and 2 h post-injection, respectively. The positive and negative result groups exhibited significant differences in triglyceride level (358.2 ± 166.4 mg/dl [range, 153-659] vs. 107.3 ± 87.5 mg/dl [range, 57-238], respectively; P = 0.019) and evident chylopericardium based on appearance in the pericardial fluid (6/0 vs. 1/3, respectively; P = 0.033). Other factors did not significantly differ between the groups. However, the presence or absence of a drainage tube within the pericardium at the time of lymphoscintigraphy was not associated with the lymphoscintigraphic result.

Despite the small cohort, the detection rate of lymphoscintigraphy with technetium-99 m for pediatric chylopericardium 2 h post-injection was 60%, and that obtained 45 min post-injection was 30%. Negative lymphoscintigraphy results may be associated with low triglyceride levels in pericardial effusion.