<prompt> Answer this question truthfullyWhat is the use of echocardiography or ultrasound in diagnosing truncus arteriosus?  <response>: <reason> Demonstrates the large truncal artery overriding the VSD Doppler colour imaging is used to evaluate pulmonary blood flow and regurgitation through tricuspid valve.Truncus Arteriosus Type I 1ev:googlevideo8970669383266720423Truncus Arteriosus Type I 2ev:googlevideo564681477766752717Truncus Arteriosus Type I 3ev:googlevideo564681477766752717Truncus Arteriosus Type I 4ev:googlevideo-3202146762215926147Truncus Arteriosus Type I 5ev:googlevideo5568593693292079875Truncus Arteriosus Type I 6ev:googlevideo-1383871098920679580 