<prompt> True about V.S.D. is, all except -Small hole closes spontaneouslyDefect is usually in membranous partEndocarditis is commonest complicationPulmonary oligemia in chest X-ray  <response>: In chest radiography, the Westermark sign is a sign that represents a focus of oligemia hypovolemia leading to collapse of vessel seen distal to a pulmonary embolism PE. ... Essentially, this is a plain X-ray version of a filling defect as seen on computed tomographypulmonary arteriogram. 