A 56-year-old male patient came to the emergency room due to a right-sided occipital headache and vertigo, which suddenly began three days before the visit, and a symptom of tilting to the right, which began one day before the visit. There was no history of an external injury within the past one week. The patient did not have any underlying diseases, history of migraines, or risk factors for stroke, except for smoking. He also did not have a history of taking antiplatelet agents. When the patient visited the emergency room, his blood pressure was 160/100 mmHg, the pulse rate was 62/min, breathing rate was 19/min, and body temperature was 36.5 °C. The results of a neurological examination showed lateropulsion to the right side, hypoesthesia on the right side of the face, ataxia in the right upper and lower limbs, and the NIH stroke scale was 2. The results of serological studies and electrocardiography were normal.\nThe diagnosis was determined to be an acute ischemic stroke because the diffusion weighted imaging (DWI) of MRI revealed a high signal intensity area in the right lateral medulla. CT angiography (CTA) was taken first at 3 days after the symptom occurred. HR vw-MRI was taken a day after (at the 4th-day). The right PICA was not observed in the first CTA, and partial spontaneous recanalization was observed on the time-of-flight MR angiography (TOF-MRA), which was taken one day after. Moreover, the sagittal 3D T1 weighted HR vw-MRI showed a T1 hyperintense intramural hematoma in the right proximal PICA (Fig. ). However, a T2 weighted 3D curved MPR image revealed the luminal dilation and intimal flap in the right proximal PICA (Fig. ). The patient was diagnosed with spontaneous isolated PICA dissection on the basis of the neurological symptoms and imaging. He was treated with antiplatelet agents and the neurological symptoms of the patient improved during course of admission.
A 54-year-old man with chronic hypertension visited ED of a local hospital following the sudden onset of posterior neck pain and left-sided homonymous hemianopsia. A brain CT revealed a subcortical hemorrhage in the right occipital lobe []. He was diagnosed with a hypertensive intracerebral hemorrhage and admitted for several days to receive conservative management before he was discharged home. However, 2 weeks later, he experienced dizziness and visited our ED. A brain MRI (diffusion-weighted images) revealed a high-intensity signal in the left cerebellar hemisphere which corresponded to the area perfused by the left PICA []. The left PICA was poorly depicted on the brain MRA [] and a presumptive diagnosis of atherosclerotic PICA occlusion was made. However, CTA of the extracranial vessels obtained the next day revealed a tapered occlusion of the left VA inside the transverse foramen []. In addition, a thin-slice contrast-enhanced axial image at the C5 level showed a double-lumen sign [], establishing the diagnosis of an extracranial VA dissection. In retrospect, the initial hemorrhage in the right occipital lobe was not an arterial bleeding but was a hemorrhagic infarction secondary to a temporary embolic occlusion of the left posterior cerebral artery. Anticoagulation with warfarin was initiated, and the patient has not experienced a recurrent infarction for over a year.