Cervical carotid artery: The most dependable alternative for the detection of a right-to-left shunt with transcranial Doppler in patients with insufficient temporal acoustic bone windows?

摘要

We are glad to respond to the very interesting commentaries on our paper by Dr Topcuoglu in his letter 《Cervical carotid artery may be the most dependable alternative place for detection of patent foramen ovale with contrast transcranial Doppler in patients with insufficient temporal sonic bone window 》. He refers, as in other letters in similar circumstances, to their interesting pioneering study in which they very nicely demonstrate the utility of submandibular internal carotid artery (ICA) contrast M-mode power Doppler ultrasound recording for the detection of right-to-left shunts (RLS). They found in 2 of 24 examined internal carotid arteries low volume RLS signals which were not found in the transtemporal middle cerebral artery (MCA) but which they could track into the anterior cerebral artery (ACA). Moreover, they found in patients in whom RLS could be demonstrated, more bubbles in the ICA than in the MCA. These findings offer indeed the submandibular ICA as an alternative in patients with insufficient temporal bone window, similar to otheralternatives such as our transforaminal approach, or vertebrobasilar recordings, or even more peripheral arteries such as the contralateral brachial or femoral arteries. However, whether the submandibular ICA approach is the most dependable, as Dr Topcuoglu suggests, remains an open question since the different alternatives have still not been directly compared. Moreover, our own experience with the submandibular ICA approach asks for caution since there are difficulties with breathing and swallowing artefacts.