: Pulmonary embolism (PE) incidence has been increasing in the last 10 years. Computed thoracic pulmonary angiography (CTPA) had a major role in PE diagnosis and prognosis. The main purpose of this study was as follows: the prognostic value of a CTPA parameter, pulmonary artery obstruction index (PAOI), in PE risk assessment and the predictive accuracy of biomarkers, D-dimer and cardiac Troponin T (c-TnT), in 7-day mortality. A second objective of the research was to investigate the relationship between imaging by PAOI and these biomarkers in different etiologies of PE. : This study comprised 109 patients with PE, hospitalized and treated between February 2021 and August 2022. They had different etiologies of PE: deep vein thrombosis (DVT); persistent atrial fibrillation (AF); chronic obstructive pulmonary disease (COPD) exacerbation; COVID-19; and cancers. The investigations were as follows: clinical examination; D-dimer testing, as a mandatory method for PE suspicion (values ≥500 µg/L were highly suggestive for PE); c-TnT, as a marker of myocardial injury (values ≥14 ng/L were abnormal); CTPA, with right ventricle dysfunction (RVD) signs and PAOI. Treatments were according to PE risk: systemic thrombolysis in high-risk PE; low weight molecular heparins (LWMH) in high-risk PE, after systemic thrombolysis or from the beginning, when systemic thrombolysis was contraindicated; and direct oral anticoagulants (DOAC) in low- and intermediate-risk PE. : PAOI had a high predictive accuracy for high-risk PE (area under curve, AUC = 0.993). D-dimer and cTnT had a statistically significant relationship with 7-day mortality for the entire sample, < 0.001, and for AF, = 0.0036; COVID-19, = 0.003; and cancer patients, = 0.005. PAOI had statistical significance for 7-day mortality only in COVID-19, = 0.045, and cancer patients, = 0.038. The relationship PAOI-D-dimer and PAOI-c-TnT had very strong statistical correlation for the entire sample and for DVT, AF, COPD, and COVID-19 subgroups (Rho = 0.815-0.982). : PAOI was an important tool for PE risk assessment. D-dimer and c-TnT were valuable predictors for 7-day mortality in PE. PAOI (imaging parameter for PE extent) and D-dimer (biomarker for PE severity) as well as PAOI and c-TnT (biomarker for myocardial injury) were strongly correlated for the entire PE sample and for DVT, AF, COPD, and COVID-19 patients.