Indian Journal of Radiology and Imaging Indian Journal of Radiology and Imaging

IMAGES
Year
: 2001  |  Volume : 11  |  Issue : 1  |  Page : 29--30

Images : Persistent hypoglossal artery


SK Venkatesh, S Nangia, M Kathuria, RV Phadke 
 Department of Radio-Diagnosis, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow (UP), India

Correspondence Address:
R V Phadke
Department of Radio-Diagnosis, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow (UP)
India




How to cite this article:
Venkatesh S K, Nangia S, Kathuria M, Phadke R V. Images : Persistent hypoglossal artery.Indian J Radiol Imaging 2001;11:29-30


How to cite this URL:
Venkatesh S K, Nangia S, Kathuria M, Phadke R V. Images : Persistent hypoglossal artery. Indian J Radiol Imaging [serial online] 2001 [cited 2019 Sep 21 ];11:29-30
Available from: http://www.ijri.org/text.asp?2001/11/1/29/28306


Full Text

Carotid-basilar anastomoses develop during fetal life between the internal carotid and basilar arterial systems for the supply of the posterior cranial circulation. The channels include trigeminal, hypoglossal, otic and pro-atlantal segmental arteries. With the development of the posterior communicating artery, these channels get obliterated but may rarely persist into adult life. The persistent trigeminal artery is the most common anomaly among the four, followed by the hypoglossal artery [1]. These channels are detected as incidental findings but may be associated with aneurysms, tumors, subarachnoid hemorrhage and arterio-venous malformations [1],[2],[3],[4],[5]. We describe MR angiographic appearances of a persistent hypoglossal artery in a patient with a posterior fossa meningioma.

 Case Report



A fifty-four-years-old man presented with a history of headache for the past six months. Clinical examination was normal. CT examination of the head showed a large calcified midline mass in the posterior fossa attached to the tentorium, suggestive of meningioma. He was further evaluated with MRI and MR angiography. Axial source images of the MR angiogram showed a vessel entering the posterior fossa at the level of the hypoglossal canal and joining the basilar artery. Maximum intensity projection (MIP) images showed a large vessel arising from the cervical internal carotid artery and joining the basilar artery. A carotid angiogram showed the anomalous vessel arising from the cervical part of the internal carotid artery coursing upwards, lying medial to the artery and entering the cranium above the level of atlas and anastomosing with the basilar artery. The left hypoglossal artery was hypoplastic and the left posterior communicating artery was demonstrated on angiograms. The tumor did not show any significant vascularity and venous phase was normal. He underwent surgical excision of the mass

 Discussion



The persistence of a primitive hypoglossal artery is a rare anomaly with an estimated incidence of 0.027% to 0.2% of all cerebral angiograms [1],[2],[3],[4],[5]. In the 4 mm stage embryo, two longitudinal arteries are formed along the basal surface of hind brain. These vessels are supplied by anastomotic channels that connect them to the internal carotid arteries. Cranio-caudally, they are trigeminal, otic, hypoglossal and pro-atlantal segmental arteries. With the development of the posterior communicating artery and vertebra-basilar system these channels regress. Otic is the first to disappear followed by the hypoglossal and lastly the trigeminal artery [1]. The hypoglossal usually arises from the internal carotid artery and rarely from the external carotid artery [3]. Arising from the internal carotid at the C1-C2 vertebral level it runs dorsally and lies lateral to the hypoglossal nerve to enter the hypoglossal canal and then into the posterior fossa to join the basilar artery. The artery widens the hypoglossal canal as noted on CT and tomograms [4]. Both vertebral arteries are usually absent or hypoplastic and the ipsilateral posterior communicating artery may not be angiographically demonstrated [1] as seen in our patient. In a review of 115 cases of persistent hypoglossal artery [5], the most common association was intracranial arterial aneurysms followed by ischemic cerebrovascular attacks, brain tumors, subarachnoid hemorrhage, trauma and arteriovenous malformations. When an aneurysm arises directly from the hypoglossal artery, ligation of the artery may be disastrous as it may the only supply to the brain stem. Presence of this artery may cause confusion during evaluation of suspected cerebrovascular symptoms and it may complicate the performance of carotid endarterectomy [2]. Angiography clearly demonstrates the anomaly but recognition of this anomaly on non-invasive imaging is important. Preoperative knowledge of these channels may suitably forewarn the surgeon in cases of skull base surgeries or carotid endarterectomy, helping them avoid disastrous results, as this vessel may be the sole supply to the brainstem. The present report has shown that MR angiography is useful in non-invasive identification of the anomalous artery.

References

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