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 42-year-old woman applied to the ophthalmology department with a complaint and history of a half-hour-long visual loss of her left eye one day ago. At clinical examination, both of her eyes were found to have full vision, and also microscopic fundus examinations revealed no pathological conditions. The patient gave a history of a prior application to an outer medical center with the same complaint, and there she had been diagnosed with a left ICA occlusion, following Doppler US and angiographic examinations. The patient applied to our department with the demand of an extracranial carotid Doppler US examination. At Doppler US, the right CCA diameter was found to be 8 mm, whereas the left one came out to be 4 mm (Figures and ). The right CCA bifurcation and the ICA and ECA were found to be normal. At the left side, spectral data for the ECA () and the particular branching which demonstrates that the vessel is ECA indeed were present, whereas there was no Doppler signal and gray-scale findings for the ICA (). Because the left CCA was hypoplastic and there were no findings of atherosclerotic plaques in other arterial segments; it was thought that the left ICA might not be suffering an occlusion at all, but instead it might well be agenetic. Based on the presumption of an ICA agenesis, a computed tomographic (CT) examination of the skull base was performed. CT images revealed a normally appearing right carotid canal but no clear image of the left one (). Then, the previous angiographic images of the patient were reevaluated, and it was then recognized that the left ECA and its branches were well visible, while the left ICA and its branches did not show any filling with contrast (). It was also noted that the filling of the left anterior and medial cerebral arteries was sustained by the patent anterior communicating artery following the injection of contrast into the right carotid artery () and also via the posterior communicating artery following the injection of the vertebrobasilary system (). In addition to the ICA agenesis, another surprising finding was that the right vertebral artery was not stemming from the right subclavian artery but instead was originating from the aortic arch, as its first branch (). It was finally understood that the patient did not have an occlusion of the left ICA, but instead her left ICA was agenetic. She also had an additional aortic arch anomaly. At the end, it was concluded that an ipsilateral CCA hypoplasia might be taken as a valuable clue in the differential diagnosis of ICA agenesis and occlusion.