Background: A growing number of studies in the last few years have searched for a potential prognostic role of MDCT to improve PE risk stratification. These studies were accompanied by puzzling details and heterogeneous results. Certain CT parameters have been nominated for this purpose. RV/LV ratio and arterial obstruction index were the most extensively studied parameters. Aim of our Study: Is to investigate the prognostic role of CT pulmonary angiography in patients with acute pulmonary embolism. Patient and method: 59 patients having severe or large sized acute PE diagnosed by CT angiography were followed through 30 days to 3 months for their short-term clinical outcome. Bad outcome indicators included: PE-related mortality, clinical deterioration and necessity for ICU aggressive treatment or thrombolytics. Patients CT prognostic parameters were assessed and statistically analyzed to determine their ability to predict major adverse outcomes of acute PE. Results: Of all CT parameters, RV diameter was the best discriminator between adverse & non-adverse outcome groups in our study, comparable only to Mastora pulmonary artery obstruction score. It showed the highest negative predictive value 95.7% and a negative likelihood ratio very close to 0. RV diameter alone performed better than the commonly used RV/LV ratio as a measure of RVD in predicting PE adverse outcome. Septal bowing, substantial grades of IVC contrast reflux, PA & SVC diameters showed weak sensitivity & specificity results. A final logistic regression model combining three parameters (RV diameter + Mastora score + Age) was able to correctly define 83.9% of adverse outcome cases and 84.7% of overall cases in our study. Conclusion: Our study supported the use of CTPA-derived indicators of right ventricular dysfunction and pulmonary artery obstruction scores as prognostic predictors in patients with acute PE.