A 59-year-old white female presented to the emergency room after slipping and falling on ice. She had a past medical history of hypertension, hyperlipidemia, and asthma. The patient smoked one half pack of cigarettes per day. An axial 3D time of flight magnetic resonance imaging (MRI) scan was performed and identified the absence of the left carotid canal with an absence of flow signal (Figure ). An unusual vessel was also seen to arise from the right cavernous internal carotid artery (Figure ). The vessel traveled in the floor of the sella turcica (Figure ). Additional imaging with 3D reconstruction from a computed tomography (CT) angiography better defined an aberrant origin of the left internal carotid artery (Figure ). CT angiography noted the presence of an anterior communicating artery aneurysm, which was bilobed and measured 7 x 11 mm. The physical examination was unremarkable for any neurological deficits. Angiography found that the aneurysm was not amenable to endovascular treatment. Therefore, the patient underwent a right-sided craniotomy for clipping of her complex aneurysm and was soon discharged home with no complications.
The patient was a 63-year-old female with hypertension and diabetes. She had no history of smoking or heart disease. She had undergone surgery to clip a cerebral aneurysm 3 years previously and the treating neurosurgeon responsible at the time had reported difficulty with catheterization of cervical arteries. She was examined with Doppler ultrasonography of carotid and vertebral arteries, which showed that the left common carotid artery had a smaller caliber than the right ( ), the left carotid bifurcation could not be observed, and the left common carotid artery only led to the left external carotid artery ( ). Angiotomography was ordered, showing agenesis of the left internal carotid artery ( ). The patient remains asymptomatic and attends regular follow-up consultations.