<prompt> Gold standard investigation for pulmonary embolism is?CT scanPulmonary angiographyMRIX-ray chest  <response>: Ans. is b i.e., Pulmonary angiography Invasive pulmonary angiography is the most accurate method definitive test or gold standard test to diagnose pulmonary embolism. However because of its invasiveness, it has virtually been replaced by CT with contrast as a diagnostic test. The findings includei. Definitive diagnosis : - Intraluminal filling defect in more than one projection.ii. Secondary signs : - These include abrupt occlusion cut-off of vessels, segmental oligemia or avascularity, a prolonged arterial phase with slow filling, or tortuoustapering peripheral vessels.Remember Investigation of choice for PE - Chest CT with contrast especially MDCTA Investigation of 2nd choice - Lung scan VQ scan Best investigation for PE - Chest CT with contrast MDCTA Most accurate investigation for PE - Invasive pulmonary angiography Gold - standard test for PE - Invasive pulmonary angiography Screening test for PE - D-dimer assay 