Diagnosis and differentiation of congenital diaphragmatic hernia from other noncardiac thoracic fetal masses

This retrospective study was designed to evaluate individual sonographic pa rameters that might help differentiate congenital diaphragmatic hernia (CDH ) from other noncardiac thoracic masses such as cystic adenomatoid malforma tion of the lung (CAML) and congenital lobar emphysema (CLE) prenatally. Tw enty-four cases of CDH, CAML, and CLE detected during prenatal ultrasound a nd documented postnatally (with surgical, autopsy, or radiological proof) w ere identified through extensive chart and record review. The hard copy gra y-scale images were retrospectively reviewed for imaging characteristics th at may differentiate the three entities. Additionally, the prospective diag nosis during prenatal ultrasound was also compared with the postnatal diagn osis. The most reliable indicators in our retrospective review included con fident visualization of a diaphragmatic defect (92.3/100.0 PPV/NPV, p less than or equal to 0.002) and/or localization of the stomach within the chest as well as the presence of severe cardiac deviation (both 92.3/62.5 PPV/NP V, p less than or equal to 0.01). Other sonographic indicators (including t he presence of cystic areas, side and size of the lesion and the presence o f polyhydramnios) offered lower levels of sensitivity and specificity. Pros pective diagnosis during real-time assessment was also integral, offering > 80% sensitivity and specificity (p less than or equal to 0.001). Accurate prenatal diagnosis of CDH is difficult despite the relative frequency oi th is lesion. The classic triad of a thoracic mass accompanying a displaced he art, absence of a normally positioned fluid-filled stomach and polyhydramni os, although seen with CDH, may not adequately differentiate this entity fr om other noncardiac fetal thoracic masses. Realtime assessment remains inte gral to the appropriate diagnosis.