Added value of lung perfused blood volume images using dual-energy CT for assessment of acute pulmonary embolism

- Dual-energy CT can provide morphological and functional lung images in the same examination.
- Adding lung perfused blood volume images using dual-energy CT technique to CT pulmonary angiography for analysis of pulmonary emboli is useful in reducing the overlooking of intrapulmonary clots.
- Dual-energy technique using a dual-source CT is clinically useful to improve the detection of acute pulmonary embolism at pulmonary CT angiography and results in a significant improvement in the radiologist's reading performance.

PurposeTo investigate the added value of lung perfused blood volume (LPBV) using dual-energy CT for the evaluation of intrapulmonary clot (IPC) in patients suspected of having acute pulmonary embolism (PE).Materials and methodsInstitutional review board approval was obtained for this retrospective study. Eighty-three patients suspected of having PE who underwent CT pulmonary angiography (CTPA) using a dual-energy technique were enrolled in this study. Two radiologists who were blinded retrospectively and independently reviewed CTPA images alone and the combined images with color-coded LPBV over a 4-week interval, and two separate sessions were performed with a one-month interval. Inter- and intraobserver variability and diagnostic accuracy were evaluated for each reviewer with receiver operating characteristic (ROC) curve analysis.ResultsValues for inter- and intraobserver agreement, respectively, were better for CTPA combined with LPBV (ICC = 0.847 and 0.937) than CTPA alone (ICC = 0.748 and 0.861). For both readers, diagnostic accuracy (area under the ROC curve [Az]) were also superior, when CTPA alone (Az = 0.888 [reader 1] and 0.912 [reader 2]) was compared with that after the combination with LPBV images (Az = 0.966 [reader 1] and 0.959 [reader 2]) (p < 0.001). However, Az values of both images might not have significant difference in statistics, because Az value of CTPA alone was high and 95% confidence intervals overlapped in both images.ConclusionAddition of dual-energy perfusion CT to CTPA improves detection of peripheral IPCs with better interobserver agreement.