A 52-year-old woman suddenly experienced vertigo and vomited while cleaning her bathtub at home and was subsequently transferred to our hospital by an ambulance. Head CT showed no abnormal findings, thus she was admitted under the suspicion of acute drug poisoning by a detergent. Although no abnormalities on a physical examination or in laboratory data were observed, her nausea and dizziness persisted. Neurologically, she presented only mild dizziness. MRI was then performed at 4 days after the onset, which showed an acute infarction in the left cerebellar hemisphere (Fig. ). The left VA was poorly visualized on MRA as compared to the right VA (Fig. ). In addition, the external diameter of the left VA on basiparallel anatomic scanning (BPAS) was narrowed, suggesting hypoplasia. The proximal portion of the left PICA was not visualized, and the adjacent distal portion appeared to be dilated on MRA (Fig. ). T1-VISTA showed a high-intensity signal area at the dilated portion (Fig. ). Conventional T1 image was obtained on admission and at 24 days after admission, but no high-intensity area was observed at both time points. Cardioembolic causes were excluded by echocardiography and 24-hour electrocardiography. According to these findings, Ischemic stroke of the cerebellum caused by dissection of the left PICA was diagnosed, and the administration of unfractionated heparin was started. Three days later, the dilated portion was enlarged on MRA, therefore, we discontinued unfractionated heparin administration. Since her blood pressure was not high, we even didn’t use antihypertensive treatment. At 8 days after the onset, cerebral angiography demonstrated the “pearl and string sign” at the proximal portion of the left PICA (Fig. ). Dilatation gradually normalized on MRA and the high-intensity signal area on T1-VISTA gradually reduced and disappeared at 4 months after the onset (Fig. ).
A 38-year-old male patient came to the emergency room due to vertigo and vomiting that had started suddenly one day before the visit. The patient complained of a left-sided occipital headache that began two days before the visit. He had no history of trauma within 1 week prior to admission. The patient did not have any underlying diseases, history of migraines, or risk factors for stroke except for smoking and alcohol consumption. His blood pressure was 170/100 mmHg, the pulse rate was 70/min, breathing rate was 20/min, and body temperature was 36.5 °C. A neurological examination showed ataxia in the left upper extremity and the NIH stroke scale was 1. The results of serological studies and electrocardiography were normal.\nThe patient was determined to have an acute ischemic stroke because the DWI of MRI showed a high signal intensity area in the left PICA territory. CTA was taken at 2 days after the onset of a headache and at 1 day after the onset of neurological symptoms. Moreover, HR vw-MRI was taken at 6 days after the onset of a headache and at 5 days after the onset of neurological symptoms. Although the left PICA was not observed on the TOF-MRA, other vessels including the left vertebral artery were normal. An intraluminal high signal intensity and mild dilation of the left proximal PICA was revealed on routine 3D HR vw-MRI, but pathognomic signs of dissection was not seen. Curved MPR image reconstructed from 3D T2 weighted HR vw-MRI showed dilation and an intimal flap in the left PICA origin and post dilation stenosis in the left proximal PICA (D). (Fig. ). The patient was diagnosed with spontaneous isolated PICA dissection based on the neurological symptoms and imaging. The patient was treated with antiplatelet agents and discharged after his neurological symptoms improved.