Variations in superior thyroid artery: A selective angiographic study.
OBJECTIVE
To investigate variations in superior thyroid artery (STA) based on digital subtraction angiography (DSA).


METHODS
Twenty five angiography studies of 15 pts performed between June 2010 and December 2012 were retrospectively evaluated. These patients underwent DSA of the head and neck region as a part of their superselective neoadjuvant intra-arterial chemotherapy protocol for treatment of laryngeal and hypopharyngeal cancers. Depending upon the location of the tumor, unilateral or bilateral arteriograms of common carotid artery (CCA), external carotid artery (ECA), and STA were performed. Arteriograms were evaluated for the site of origin and branching pattern of STA. STA anatomy was ascribed to one of the three branching patterns.


RESULTS
A total of 25 angiograms were evaluated, including 14 right and 11 left. On the right side, STA was noted to arise from ECA in 10 (71.5%), bifurcation of CCA in 3 (21.5%), and CCA in 1 (7%) patient. Left STA was seen to arise from ECA in 8 (72.5%), bifurcation of CCA in 2 (18.5%), and internal carotid artery (ICA) in 1 (9%) patient. Type III branching pattern (non-bifurcation, non-trifurcation) was found to be the most frequent (52%). Infrahyoid branch was found to be the most consistent in terms of its origin from STA.


CONCLUSIONS
Origin of STA is predictable, arising from ECA in more than 70% cases. Branching pattern of STA, following origin from ECA, is, however, highly variable. Knowledge concerning the origin and branching pattern of STA is essential in enhancing precision and decreasing morbidity related to the surgical and interventional radiological head and neck procedures.
Department of Radiodiagnosis, All India Institute of Medical Sciences, New Delhi, India.
Pankaj
P
Gupta
Department of Radiodiagnosis, All India Institute of Medical Sciences, New Delhi, India.
Ashu Seith
AS
Bhalla
Department of Radiodiagnosis, All India Institute of Medical Sciences, New Delhi, India.
Sanjay
S
Thulkar
Department of Radiodiagnosis, All India Institute of Medical Sciences, New Delhi, India.
Atin
A
Kumar
Department of Radiation Oncology, All India Institute of Medical Sciences, New Delhi, India.
Bidhu Kalyan
BK
Mohanti
Department of Otorhinolaryngology, All India Institute of Medical Sciences, New Delhi, India.
Alok
A
Thakar
Department of Medical Oncology, All India Institute of Medical Sciences, New Delhi, India.
Atul
A
Sharma
Anatomic variations; digital subtraction angiography; superior thyroid artery