Korean Circ J.  2016 Jan;46(1):48-55. 10.4070/kcj.2016.46.1.48.

Prediction of Intimal Tear Site by Computed Tomography in Acute Aortic Dissection Type A

• Kim JS
• Park KH
• Lim C
• Kim DJ
• Jung Y
• Shin YC
• Choi SI
• Chun EJ
• Yoo JY

• KMID: 2223769
• DOI: http://doi.org/10.4070/kcj.2016.46.1.48

Abstract

BACKGROUND AND OBJECTIVES
Preoperative identification of intimal tear site in acute type A dissection will help procedural planning. The objective of this study was to determine the key findings of computed tomography (CT)-based prediction for tear site and compare the accuracy between radiologists and surgeons.
SUBJECTS AND METHODS
Multi-detector CT (MDCT) images from 50 patients who underwent surgical repair of type A aortic dissection were retrospectively reviewed by 4 cardiac surgeons with limited experience or by 3 radiologists specialized in cardiovascular imaging. Surgical findings of intimal tear site were used as references.
RESULTS
In surgical findings, the locations of intimal tear that were identified in 43 patients included aorta (n=25), ascending with arch (n=7), and arch only (n=11). The rest were retrograde dissections from the tear of descending aorta. Key CT findings that were most frequently found were defect in the intimal flap shadow (30.0+/-4.0 patients/reviewer, accuracy 87.0+/-11.7%) and differential filling of false lumen by phase and location (9.4+/-2.9 patients/reviewer, 84.8+/-10.4%). Surgeons predicted tear site (75.0+/-7.7% vs. 86.7+/-1.2%, p=0.055) and specified flap defect (80.5+/-10.3% vs. 95.7+/-7.4%, p=0.073) with lower accuracy than radiologists.
CONCLUSIONS
With MDCT imaging, well-educated surgeons could be accurate in three fourths of cases. There was room for improvement through experience. Considering the substantial possibility of inaccuracy, critical decisions on CT images should be made through thorough reviewing by as many experienced radiologists and surgeons as possible.

Keyword

Aorta; Aortic dissection; Computerized tomography

MeSH Terms

Aorta
Aorta, Thoracic
Humans
Retrospective Studies
Tears*

Figure

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  Fig. 1 The aorta is divided into four segments to categorize the predicted site of intimal tear according to the probability of need for arch replacement. 1; ascending aorta, 2; inferior arch, 3; superior arch, 4; beyond arch/descending thoracic aorta.

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  Fig. 2 Distinct intimal flap defect found in the ascending aorta (A), the anterosuperior arch (B), and origin of aberrant right subclavian artery (C and D). Unusual findings in the transverse sections (E and F) turned out to be complete transection and distal invagination of the intimal flap in the sagittal section (G). All reviewers accurately pointed out those findings.

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  Fig. 3 Tiny flap defect is barely identifiable in the axial section (A and B), but only in the sagittal section (arrow in C and D). While the radiologists were all accurate, some surgeons missed such findings. Thrombosis of false lumen in the proximal ascending aorta is present on C and D.

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  Fig. 4 One of two flap discontinuities shown in the sagittal section is concordant with the real intimal tear (arrows in A and C). The other one (arrowheads in B and C) is caused by folding of the intimal flap, leading to false positive diagnosis by five of the seven reviewers, including one radiologist.

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  Fig. 5 The cases of retrograde dissection from descending aortic tear for which all radiologists were inaccurate. The point of abrupt change in false lumen patency (A-C, arrow) or point of suspicious contrast leakage (D and E, arrow) turned out to be free from intimal tear.

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