'Apical cap' on CXR is seen in:

Ans. A. Dissecting aneurysmDissecting aneurysmCXRa. Normal CXR in 25% casesb. Calcification sign (inward displacement of calcification plaque by >4-10mm from outer aortic contour) or the calcification in the aortic knuckle, which is separated from the outer margin by more than 1cm, is said to be suggestive of dissection.c. Disparity in size between ascending and descending datad. Irregular wavy contour/indistinct outline of aortae. Localized dilation of aortic knuckle and upper descending aorta, which may give rise to prominent lump' signf. Lateral projection of aortic knuckleg. Widening of superior mediastinumh. Left sided pleural effusioni. 'Apical cap' signj. Rightward displacement of trachea