Prenatal diagnosis of fetal unilateral lung agenesis complicated with cardiac malposition

BACKGROUND Fetal unilateral lung agenesis, complicated with cardiac shifting, is a rare anomaly, the diagnosis of which remains a challenge for many sonographers in routine screening programs. The present study describes a systematic approach for the diagnosis of fetal unilateral lung agenesis and cardiac malpositions in routine prenatal screening. METHODS A total of 18 cases of fetal unilateral lung agenesis complicated with cardiac malposition were reviewed. A systematic method was proposed to identify the fetal left side and right side according to the fetal head position and posture by acquiring a long axis and transverse view of the fetus. Fetal unilateral lung agenesis was diagnosed by evaluation of the ipsilateral pulmonary artery. The diagnosis was confirmed by postnatal echocardiography, digital radiology, and computed tomography after birth or by autopsy findings. RESULTS The left-sided fetal heart with the cardiac apex rotating to the left and posterior were confirmed in all 7 left lung agenesis cases, while the rightward shifting of the fetal heart together with the cardiac axis deviating to the right were confirmed in all 11 cases of right lung agenesis. The disappearance of the ipsilateral pulmonary artery was confirmed in all 18 cases of unilateral lung agenesis. Cardiac anomalies were present in a total of 7 of the 18 cases of lung agenesis with 4 of 7 in cases of left lung agenesis and 3 of 11 in cases of right agenesis. CONCLUSIONS The systematic approach introduced in the current report is helpful in the diagnosis of fetal unilateral lung agenesis complicated with cardiac malposition. The information provided by this study may be helpful to better understand unilateral lung agenesis anatomically and to facilitate its potential examination.