Severity assessment of pulmonary embolism using dual energy CT - correlation of a pulmonary perfusion defect score with clinical and morphological parameters of blood oxygenation and right ventricular failure.

OBJECTIVE: To correlate a Dual Energy (DE)-based visual perfusion defect scoring system with established CT-based and clinical parameters of pulmonary embolism (PE) severity.
METHODS: In 63 PE patients, DE perfusion maps were visually scored for perfusion defects (P-score). Vascular obstruction was quantified using the Mastora score. Both scores were correlated with short-axis diameters of the right and left ventricle, their ratio (RV/LV ratio), width of the pulmonary trunk, a number of clinical parameters and each other. Univariate and multivariate analyses were performed. Times to generate both scores were recorded.
RESULTS: After univariate and multivariate analysis, a significant (p < 0.05) correlation with the P-score was shown for the Mastora score (r = 0.65), RV/LV ratio (r = 0.47), width of the pulmonary trunk (r = 0.26), troponin I (r = 0.43) and PaO(2) (r = -0.50). For the left ventricular diameter, only univariate analysis showed a significant correlation. Mastora score correlated significantly with RV/LV ratio (r = 0.36), width of the pulmonary trunk (r = 0.27), PaO(2) (r = -0.41) and troponin I (r = 0.37). Mean time for generating the P-score was significantly shorter than for the Mastora score.
CONCLUSIONS: A DE-based P-score correlates with a number of parameters of PE severity. It might be easier and faster to perform than some traditional CT scoring methods for vascular obstruction.