In the past few years, we have seen increasing demand for computer tomography pulmonary angiographies (CTPAs) intended to rule out pulmonary embolism (PE). Such requests even escalated during the COVID-19 pandemic. Beyond clinical symptoms, increased plasmatic D-dimer concentration was the main reason for CTPA requests. We decided to investigate and confirm the role of D-dimer concentration in PE diagnosis to help in optimizing requests from clinicians. We had recently installed spectral dual-layer CT and so we asked, from a radiologist’s point of view, how does this technology help us to detect PE? In this paper, we present a retrospective cross-sectional study of three groups of computer tomography pulmonary angiographies (500 in each group) conducted in our hospital. The first group of patients underwent scans by conventional multidetector CT, the second group by dual-layer spectral CT, and the third by dual-layer spectral CT after having tested positive for COVID-19 test and showing CT signs of viral pneumonia. We compared prevalence of pulmonary embolism, inconclusive pulmonary embolism findings, and plasmatic D-dimer concentrations with reference to presence and extent of pulmonary embolism among each group. We confirmed increased level of D-dimer in cases with PE. In patients COVID-19 negative, D-dimer levels were also higher in cases with more extensive PE. In patients with COVID-19 pneumonia, the usual threshold of 0.5 mg/L D-dimer concentration could be doubled while maintaining 100% sensitivity. Techniques of spectral CT helped us to reduce the number of inconclusive PE findings.