lung embolismsubsegmental pulmonary embolismmultiple pulmonary embolismspulmonary embolism diagnosissubmassive pulmonary embolismpulmonary embolism prognosispulmonary embolism pregnancyunprovoked pulmonary embolismmassive pulmonary embolismchronic pulmonary embolismbilateral pulmonary embolismsegmental pulmonary embolism