The incidence of vertebrobasilar dissecting aneurysms (VBDAs) is about 1/100,000~1.5/100,000, and it is one of the most important causes of stroke in young and middle-aged people. In recent years, with the development of medical imaging technology, the detection rate of this disease has been increasing year by year. The natural prognosis of VBDAs is complex and varied, with uncertainty: (1) it may have a benign course, and the imaging follow-up may show that the diseased vessels are repaired and improved or remain stable for a long period of time; (2) it may present with ischemic stroke caused by hemodynamic alteration or thromboembolism, which may result in severe neurological impairment; (3) it may occur as a result of rupture of aneurysms leading to subarachnoid hemorrhage, endangering the patient's life; (4) progressive enlargement of VBDAs causing occupying effects, which may be manifested as headache in mild cases, or hemiplegia of limbs and choking on drinking water in severe cases. Up to now, there is a lack of objective and uniform diagnostic and therapeutic guidelines for the natural regression of VBDAs and the benefits of surgery, and the treatment is mostly empirical, which makes it difficult to accurately determine the clinical prognosis of VBDAs and formulate appropriate treatment strategies.

Therefore, against the above background, we designed the present study. This study was a multicenter, prospective, registry study. We enrolled patients with unruptured VBDAs who met the inclusion and exclusion criteria, and a multi-disciplinary team formulated the treatment modalities for the patients, which were categorized into the conservative observation group, the stent-assisted coiling group, and the flow diverter group. The aim of our study was to investigate the effects of different treatment modalities on the prognosis of patients with VBDAs, as well as to stratify the risk factors of the patients, to explore the individualized treatment modalities of the patients, and to improve the diagnosis and treatment of this clinically refractory cerebrovascular disease.

Inclusion Criteria:

1. Age 18-80 years old;
2. Patients diagnosis of "unruptured vertebrobasilar dissecting aneurysm".

Exclusion Criteria:

1. Patients did not undergo a cranial MRI;
2. Missing critical clinical baseline;
3. Missing pre-treatment imaging;
4. Receiving microsurgery;
5. The combination of other serious diseases during diagnosis will significantly affect the follow-up of patients;
6. CT/MRI shows intracranial hemorrhage or subarachnoid hemorrhage (SWI microbleeds are ignored).

Patients diagnosis of "unruptured vertebrobasilar dissecting aneurysm".