CTPA follows the definition of a CTA above, with the addition that the timing of the scan is tailored so that contrast enhances the pulmonary arterial system to identify potential filling defects. OR Discussion of Procedures by Variant Variant 1: Suspected pulmonary embolism. Low or intermediate pretest probability with a negative D-dimer. Initial imaging. Because this scenario is clinically important, it is presented in Variant 1 despite the fact that the literature does not support advanced imaging [12-16]. Radiographs are typically performed because the differential diagnosis is broad in this patient population. CTPA The literature does not support the use of CTPA for the evaluation of suspected PE. This is in keeping with the fact that no advanced imaging is supported for patients included in this clinical scenario [8,12-16]. CT Chest With IV Contrast The literature does not support the use of CT chest with IV contrast for the evaluation of suspected PE for patients with low to intermediate probability and negative D-dimer [8,12-16]. The use of CT for alternate diagnoses is beyond the scope of this document. CT Chest Without and With IV Contrast The literature does not support the use of CT chest without and with IV contrast for the evaluation of suspected PE for patients with low to intermediate probability and negative D-dimer [8,12-16]. The use of CT for alternate diagnoses is beyond the scope of this document. CT Chest Without IV Contrast The literature does not support the use of CT chest without IV contrast for the evaluation of suspected PE for patients with low to intermediate probability and negative D-dimer [8,12-16]. The use of CT for alternate diagnoses is beyond the scope of this document.
Suspected Pulmonary Embolism PCAs. CTPA follows the definition of a CTA above, with the addition that the timing of the scan is tailored so that contrast enhances the pulmonary arterial system to identify potential filling defects. OR Discussion of Procedures by Variant Variant 1: Suspected pulmonary embolism. Low or intermediate pretest probability with a negative D-dimer. Initial imaging. Because this scenario is clinically important, it is presented in Variant 1 despite the fact that the literature does not support advanced imaging [12-16]. Radiographs are typically performed because the differential diagnosis is broad in this patient population. CTPA The literature does not support the use of CTPA for the evaluation of suspected PE. This is in keeping with the fact that no advanced imaging is supported for patients included in this clinical scenario [8,12-16]. CT Chest With IV Contrast The literature does not support the use of CT chest with IV contrast for the evaluation of suspected PE for patients with low to intermediate probability and negative D-dimer [8,12-16]. The use of CT for alternate diagnoses is beyond the scope of this document. CT Chest Without and With IV Contrast The literature does not support the use of CT chest without and with IV contrast for the evaluation of suspected PE for patients with low to intermediate probability and negative D-dimer [8,12-16]. The use of CT for alternate diagnoses is beyond the scope of this document. CT Chest Without IV Contrast The literature does not support the use of CT chest without IV contrast for the evaluation of suspected PE for patients with low to intermediate probability and negative D-dimer [8,12-16]. The use of CT for alternate diagnoses is beyond the scope of this document.