Imaging of carotid artery dissection

A 32-year-old woman presented to the emergency room complaining of a headache and blurred vision in her left eye. Two weeks before presentation she felt ‘sinus pressure’ and heard a swishing sound in her left ear associated with pain and tightness on the left side of her head, face, and neck, most prominent at the angle of the jaw. She sought emergent attention when she felt a ‘gritty sensation’ in her left eye and noted that her left eyelid was red and droopy. On evaluation vitals were normal. Her forehead showed no vasomotor or sudomotor changes. She had an injected left conjunctiva with miotic pupil (left 3 mm, right 5 mm) which was reactive to light and accommodation. Corneal fluorescein uptake and fundoscopic exam were normal. Vision was 20/20 in both eyes. Extraocular movements were normal, but the patient complained of pain in the left eye. The higher cortical, other cranial nerve, motor, sensory, and cerebellar functions were normal. Imaging studies showed a left internal carotid artery dissection extending up to the base of the skull. Craniocervical artery dissection presents in a variety of ways including headache and neck pain, oculomotor Horner’s syndrome as in our patient, and signs of cerebral ischemia that may be delayed by hours or days. Though rare (2.5 to 3 cases per 100,000 in the general population) (1, 2), the diagnosis is made because of awareness of its clinical manifestations and because of advances in non-invasive imaging, chiefly color duplex ultrasonography, CT angiography, MRI and MR angiography, and conventional catheter angiography. These rely on imaging of the mural pathology, principally an intramural hematoma, sometimes resulting in and sometimes resulting from an intimal tear. Color duplex ultrasound, not performed in our patient, detects mural hematoma and thrombus as a thickened hypoechoic wall. Because most internal carotid artery