<prompt> Which investigation is most diagnostic of pulmonary emboli?CTPAVP scanHRCTD- Dimer Assay  <response>: Computed Tomography Pulmonary Angiography CTPA is the initial imaging modality of choice for stable patients with a suspected pulmonary embolism. Pulmonary angiography shows emboli directly but it is an invasive procedure CT is noninvasive, cheaper and widely available. so, its the most diagnostic investigation of choice. - D-Dimer is the screening investigationin PE pts 