Reading a chest X-ray requires a methodical approach that can be applied to all films so that abnormalities are not overlooked. A lateral X-ray is used to localize lesions in the AP dimension, locate lesions behind the left side of the heart. At its simplest, a chest X-ray abnormality can be classified into increased or decreased density. The chest X-rays show hazy bilateral opacification sparing the lung bases and apices. The films taken in inspiration and expiration can give clue about an inhaled foreign body during diagnosis. In cases of elevated pulmonary venous pressure, different X-ray signs develop progressively as it rises. The chest X-ray may be normal in pulmonary embolism or may demonstrate non-specific abnormalities such as linear atelectasis, small pleural effusion and elevated hemidiaphragm. Computed tomography (CT) is more sensitive than chest X-ray in the detection of complications, such as pleural effusion and pneumothorax.