The typical branching pattern of the aortic arch was found in 339 patients(66,3%).
The most common variant was the common origin of the BT and LCCA,
seen in 65 patients(12,7%).This variant is usually termed “bovine aortic arch” which is one of the most often used misnomers in the medical field.[6] A true bovine arch does not resemble aortic arch encountered in human.
In cattle,
there is a single vessel,
brachiocephalic trunk,
originating from the aortic arch.[7]
The second most common variant was the left vertebral artery(LVA) arising directly from the aortic arch proximal to the LSA in 37 patients(7,2%).
Additionally two patients(0,4%) had combination of abovementioned variants.
In another two patients(0,4%) the LVA was arising distal to the LSA.
The right sided aortic arch was depicted on 27 MDCT studies(5,3%).
There are three types of this anomaly: type I – with mirror image branching pattern,
type II – with left aberrant subclavian artery,
type III – with isolated subclavian artery.[8] In our study only types I and II were present.
In this group there was a mirror branching pattern in 14 patients and 13 patients had aberrant subclavian artery.
In the latter group aberrant subclavian artery was arising from diverticulum of Kommerell in 5 patients,
in one patient there was common origin of common carotid arteries and in one case the LVA was arising from the LCCA.
Coarctation of the aorta was found in 16 cases(3,1%): in one case it was accompanied by the LVA arising directly from the aortic arch and in two another by common origin of the BT and LCCA.
There were 12 cases(2,3%) of aberrant right subclavian artery(ARSA) arising from the left sided aortic arch.
In this group 2 patients had common origin of common carotid arteries,
one had diverticulum of Kommerell,
in one case LVA was arising from the aortic arch and in another vertebral artery was arising from the right common carotid artery(RCCA).
Five patients(1%) had hypoplastic aortic arch and one of them had additional common origin of the BT and LCCA.
Interrupted aortic arch was found in 4 cases(0,8%) and double aortic arch in another 2 cases(0,4%).
In one patient with double aortic arch,
the LVA was arising from the left aortic arch.