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Article History

Received: 10 October 2016

Revised: 20 March 2017

Accepted: 3 April 2017

First Online: 5 May 2017

Compliance with ethical standards

: The results of this article were partially presented at the Annual Meeting of the European Society of Head in Neck Radiology 2015.

: The scientific guarantor of this publication is Dr. Lorenzo Preda.

: The authors of this manuscript declare no relationships with any companies whose products or services may be related to the subject matter of the article.

: The authors state that this work has not received any funding.

: Elena Tagliabue and Sara Raimondi kindly provided statistical advice for this manuscript.

: Written informed consent was obtained from all surviving subjects (patients) in this study, while for subjects who had died consent was waived.

: Institutional Review Board approval was obtained

: • observational study• performed at one institution