The formation of a potential acoustic window was based on the opinion of at least one observer, i.e., in the blind evaluation, 20 cases were considered to have a potential acoustic window (Table 2).
In 2 cases, no effective acoustic window was identified.
The formation of an acoustic window was essential for ultrasound evaluation of the thoracic cavity.
An acoustic window created by a pleural effusion was easily detected.
Radiographic examination should be conducted prior to an ultrasound to identify the location of an acoustic window. When nodules are dispersed throughout the thorax, the radiographic examination is superior to ultrasound.
Factors contributing to diagnostic errors were patient-related including right atrial isomerism (in 53%) and poor acoustic windows (in 47%).
One neonate on a high-frequency oscillatory mode of ventilation had poor acoustic windows. Additionally, in one case artifacts made the false positive interpretation of mixed variety, which could have been prevented by checking with Doppler image or repeated studies.
In cases with poor acoustic windows, mixed variety of TAPVR or heterotaxy syndrome, the use of additional imaging should be considered to provide complete preoperative data.
Factors reducing its diagnostic accuracy were the mixed variety, right atrial isomerism and poor acoustic windows. Use of additional imaging modality is recommended in such cases to provide a complete diagnosis.
However the limitations of the study are small sample size, inclusion of all age groups and diagnostic precision by echocardiography decreases in older age groups because of poor acoustic windows.