Incidence and factors associated with serosal and soft tissue enhancement after cardiac catheterization in infants

Diffuse serosal and soft tissue enhancement is a rare imaging phenomenon observed in infants following cardiac catheterization. The appearance of serosal and soft tissue enhancement can mimic pneumoperitoneum, potentially leading to misdiagnosis and unnecessary diagnostic procedures. While serosal and soft tissue enhancement has been documented in case reports, no studies have systematically evaluated the risk factors associated with its development.

To determine the frequency of serosal and soft tissue enhancement in infants following cardiac catheterization and identify clinical and imaging factors associated with this phenomenon.

This retrospective study analyzed infants who underwent cardiac catheterization at our institution between January 2010 and September 2019. Abdominal radiographs obtained within 2 days of the procedure were independently reviewed by three pediatric radiologists for the presence of serosal and soft tissue enhancement. Clinical data, including contrast dose, renal function, and cardiac physiology, were extracted from the electronic medical record. Statistical analysis, including t-tests and logistic regression, was performed to identify factors associated with serosal and soft tissue enhancement, with inter-observer reliability assessed using the Fleiss kappa test.

Among 1,796 infants who underwent cardiac catheterization, 294 had follow-up abdominal radiographs. Serosal and soft tissue enhancement was identified as present by all three radiologists in 21 patients (7.1%). Significant factors associated with serosal and soft tissue enhancement included lower pre- and post-catheterization creatinine levels (pre- 0.36 ± 0.17 vs 0.46 ± 0.30 mg/dL; P=0.043; post- 0.35 ± 0.11 vs 0.45 ± 0.29 mg/dL; P=0.009), higher contrast volume (31.8 ± 21.4 vs 21.0 ± 18.1 mL; P=0.013), and higher contrast volume per body surface area (123.0 ± 69.2 vs 80.8 ± 56.2 mL/m^2; P=0.002). Serosal and soft tissue enhancement occurred more frequently in patients with bi-ventricular cardiac physiology (125/294; 42.5% compared to 169/294; 57.5%).

Serosal and soft tissue enhancement occurs in a small proportion of neonates following cardiac catheterization and is associated with higher contrast dosages and body surface area-adjusted contrast volumes. Awareness of serosal and soft tissue enhancement among pediatric radiologists is helpful to avoid misdiagnosis of pneumoperitoneum.