Type:
Educational Exhibit
Keywords:
Haemorrhage, Dissection, Aneurysms, Computer Applications-Detection, diagnosis, Complications, CT-High Resolution, CT-Angiography, CT, Cardiovascular system, Arteries / Aorta, Anatomy
Authors:
J. M. Guilmette1, C. Dennie2, A. Semionov 1, G. Gahide3, J. Pressacco1, R. Fraser4, M.-P. Cordeau1, C. Chartrand-Lefebvre1; 1Montreal, QC/CA, 2Ottawa, ON/CA, 3Sherbrooke, QC/CA, 4Montreal, CA/CA
DOI:
10.1594/ecr2013/C-1275
Background
Anatomically,
pulmonary arteries and bronchi along with the lymphatic channels are closely surrounded by a sheath of connective tissue.
This sheath is connected to the mediastinum (3).
In aortic dissection,
especially Stanford type A,
this sheath loses its firm tightness,
resulting in the formation of a hemomediastinum (3).
At this point,
this condition can lead to many complications.
Frequently,
hemorrhagic extravasations into an extrapleural route can create a 'apical cap'.
Also,
the pressure exerted by the hemomediastinum can fissure the pleura and form a hemothorax (1,
4).
Exceptionally,
an increased in mediastinal pressure may rupture the adventitia of the aorta to result in a hemorrhagic infiltration along the sheath shared between the aorta and the pulmonary artery.
Rarely,
extravasation of blood spreads along the pulmonary arteries to the lung interstitium.
Previously,
the connective 'sheath' was described as an 'adventitia' shared by the aorta and the pulmonary trunk (2,
3).
However,
we believe that it is actually a sheath composed of connective tissue,
which is common to the aorta and the pulmonary trunk (Fig.
1).