A 46-year-old woman with no previous medical history first visited ophthalmologic department with amaurosis fugax for about 20 min and persistent visual impairment of left eye. The corrective vision examination showed that visual accuracy of the left eye is 0.1 and the right eye is normal 1.0. Pupillary light reflex test showed relative afferent pupillary defect (RAPD) of the left eye. The fundus examination did not find significant abnormalities (Fig. A). The Visual-Evoked Potential (VEP) test demonstrated the prolonged latency and declined amplitude of P100 wave of the left eye (Fig. B), indicating the impairment of left visual pathway. The fundus fluorescein angiography found that the arm-retinal circulation time of left eye was 25 s (Fig. C and Additional file : Video 1), whereas the normal time window is only 10 ~ 15 s. The right eye did not present any abnormality (Fig. C). Accordingly, the CRAO diagnosis was confirmed and ophthalmologic examination indicated that the occlusion might occur in the pathway from aortic arch to ophthalmic artery.\nTherefore, the patient was transferred to neurological department. The MR angiography (MRA) found that bilateral ICAs were absent concurrent with dilated vertebral and basilar arteries. Meanwhile, there were variations in the circle of Willis with opened right posterior communication artery (PCoA) and absence of left PCoA (Fig. A). Moreover, CT angiography (CTA) images (Fig. B, C) illustrated that bilateral hypoplasia of the ICAs from carotid bifurcation with thin remnants and the bilateral bony carotid canals still existed in CT bone window (Fig. D), confirming the diagnosis of bilateral ICAs hypoplasia but not ICAs agenesis. Hereto, we can depict the characteristics of the blood flow of the case: (1) due to bilateral ICAs hypoplasia, vertebrobasilar artery system takes the responsibility to provide blood supply to the whole brain and results in dilated vertebral and basilar arteries; (2) as a result of variation of the circle of Willis, the blood flow first supplies right middle cerebral artery (MCA) and ophthalmic artery via opened right PCoA and then the left MCA and ophthalmic artery via opened anterior communicating artery (ACoA).\nHowever, the amaurosis fugax and lasting visual impairment of left eye cannot be well interpreted. According to the standard of TOAST typing of stroke, the cardiogenic factors were evaluated then. Atrial fibrillation and valve vegetation were not detected by 24-h dynamic electrocardiogram and echocardiograms. Transesophageal echocardiography (TEE) revealed patent foramen ovale (Fig. ) and blood split-flow from right to left atrium when doing Valsalva breath during the Foaming test (Additional file : Video 2). Therefore, the amaurosis fugax and persistent visual impairment of left eye was caused by cardiogenic embolism.\nAspirin 100 mg/day was given to the patient and PFO occlusion surgery was recommended by us. However, the patient refused the surgery and was lost to follow-up.
A 25-year-old female patient visited the neurology outpatient clinic with severe holocranial headache that had persisted for 2 months. The pain was intermittent and relieved by analgesics. Clinical examination was unremarkable.\nComputed tomography (CT) scan of the brain showed absent bony carotid canal on the left side [Figure and ]. Magnetic resonance angiography (MRA) [Figure and ] showed complete absence of the cervical and petrous part of the left ICA. An abnormal vessel was seen arising from the cavernous segment of the right ICA. This vessel was passing across the floor of sella, reconstituting the cavernous and supraclinoid segments of the left ICA, and continuing as the left MCA. Aplasia of A1 segment of left ACA was also observed.\nMagnetic resonance imaging (MRI) showed absent left ICA flow void with an abnormal flow void in the sella [Figure and ]. No evidence of any SAH or aneurysm was seen. The vertebrobasilar system was normal.\nDoppler imaging [Figure –] showed complete absence of the left ICA. The left common carotid artery (CCA) was seen continuous with the external carotid artery (ECA). The left CCA and ECA showed high resistance flow with narrow systolic peak and low diastole. Since the right CCA has to compensate for the absent left ICA, it showed low resistance flow with broad systolic peak and high diastolic flow.\nLateral radiograph of the skull [] and the corresponding sagittal reformatted CT scan [] showed a well-defined lytic area in the anteroinferior aspect of the sella due to the abnormal intercavernous vessel traversing across it.