Abstract:

Objective    To explore the clinical value of the dual-source CT virtual endoscopy (CTVE) by the ECG gating technique in the assessment of thoracic aortic dissection (AD). Methods    Data from 50 patients diagnosed as having thoracic aortic dissection aneurysms using dualsource CT were retrospectively reviewed. CTVE images were reconstructed at a workstation. Imaging features including the scope and configuration of the AD tear and intimal flap were reviewed according to CTVE. Evaluated results of CTVE images were divided into the clear （n=40）and unclear （n=10）tear groups in order to identify the association between concentration of contrast media and display of the tear. The difference was analyzed in the CT value of the true lumen near the tear between the two groups. Results     There were 22 patients with Stanford type A AD and 28 with type B among a total of 50 patients,  and CTVE revealed 40 cases in the clear tear group (80%), and 10 in the unclear group(20%) including 4 without display and 6 with poor display of the tear. No difference was shown in the mean CT value of the true lumen near the tear between the two groups (P>0.05). However, the marked artifact and noise were identified in the area of the tear in the lumen. 16 fusiform or oval tears and 24 irregular ones in CTVE images were shown in the clear tear group. In CTVE images, the torn intima could be clearly shown in 45 cases (90%), spiral ones in 35 and the others in 10. Conclusion    Dual-source CTVE an display the three-dimensional structure of the tear and intima of thoracic AD. Poor display of the tear is not associated with the concentration of contrast media.

Key words: Dual-source CT; Virtual endoscopy; Thoracic aortic dissection; Tear