Quantitative Assessment of DECT Perfusion Parameters in Acute Pulmonary Embolism: Association with CT-Based Severity Indices

Background: Acute pulmonary embolism (PE) is a clinically serious and potentially fatal condition that requires rapid diagnosis and accurate assessment of disease severity. Although computed tomography angiography (CTA) is the primary imaging modality for detecting emboli, it mainly provides morphological information and does not directly assess pulmonary perfusion. Dual-energy computed tomography (DECT) enables simultaneous anatomical and perfusion imaging using iodine mapping. Objectives: This study aimed to evaluate the association between DECT-derived perfusion parameters and established CT-based severity indices, including the perfusion defect score and perfusion defect volume (PDvol), which were quantified using dedicated dual-energy post-processing software (LungPBV, Syngo Dual Energy, Siemens Healthcare, Forchheim, Germany), in patients with acute PE. These parameters were also compared with established radiologic severity indicators, including the CTA obstruction score and the right ventricular/left ventricular (RV/LV) diameter ratio. Patients and Methods: This retrospective analysis included 35 patients with confirmed acute PE from among 280 individuals who underwent DECT between June 2013 and December 2013. CTA obstruction scores were calculated using the Qanadli method. RV/LV diameter ratios were calculated on axial CTA images. Perfusion defect scores were determined using a segment-based scoring system on iodine maps. PDvol was determined semi-automatically using dedicated volumetric software. Correlations between perfusion parameters and established severity markers were assessed statistically. Results: The mean CTA obstruction score was 33.7 ± 22.4%, and the mean RV/LV diameter ratio was 1.06 ± 0.2. The mean perfusion defect score was 27.4 ± 15.1%, and the mean PDvol was 23.8 ± 11.8%. Significant positive correlations were observed between segmental obstruction on CTA and corresponding perfusion defects (P < 0.001). PDvol showed a statistically significant association with both the CTA obstruction score and the perfusion defect score, whereas no statistically significant association was observed between PDvol and the RV/LV ratio. Conclusion: DECT perfusion imaging provides both qualitative and quantitative assessments of pulmonary perfusion abnormalities in acute PE. Quantitative assessment using PDvol correlates with the CTA obstruction score and may provide objective information regarding imaging-based disease burden.