This study will evaluate the feasibility to predict the prognosis of IDA with IMH by DCE-MRI and provide theoretical basis for the prognosis and intervention of the disease.

Intracranial dissecting aneurysm (IDA) was a challenging disease and could result in stroke in young and middle-aged adults. Intramural hematoma, one of the typical imaging findings of IDA, can grow continuously in untreated IDA. Due to relatively high complication rate associated with surgical procedures, endovascular treatments have become the first-line therapy for such lesions. According to whether the parent artery was maintained, endovascular treatment was divided into deconstructive (proximal arterial occlusion and internal trapping) and reconstructive (stent implantation with or without coiling) techniques . However, recanalization of IDA was a great challenge for endovascular treatment and influenced the prognosis of patients.

The formation of an IMH is a critical event in the progress of IDA and IDA may grow because of recurrent IMH even after deconstructive endovascular treatment. Increased IMH size could result in severe compression symptoms or even death. At present, the mechanism of the continuous growth of intramural hematoma after endovascular treatment of IDA is still unclear. Some authors believe that the continuous hemorrhage of the vasa vasorum in the IMH results in the continuous enlargement of the IMH. However, this theory has not been proved by imaging in vivo.

Dynamic contrast-enhanced magnetic resonance imaging analysis for prognosis of intracranial dissecting aneurysm with intramural hematoma after endovascular treatment (DEMAT) is a prospective trial designed to collect a large series of patients with IDAs treated endovascularly to predict the prognosis of IDA with IMH by DCE-MRI and provide theoretical basis for the prognosis and intervention of the disease.

Inclusion Criteria:

adult patients (age 18-80 years) patients' ability to cooperate during the MRI examination; patients who are were diagnosed with IDA according to DSA and MRI; expectation of adequate patient safety during these examinations; unequivocal evidence by MRI (IMH>5 mm on the perpendicular plane to the long axis of the vessel) of IDA; IDA treated by the endovascular approach; patients' willingness to participate in the study.

Exclusion Criteria:

patients with pre-existing diagnoses of arteritis, fibromuscular dysplasia, iatrogenic aneurysms or pseudoaneurysms; extracranial dissecting aneurysms extended into the intracranial segment; patients with other diseases or poor general condition with expected survival of less than 2 year; the IDA has already been treated by the endovascular treatment; patients lacking DCE-MRI follow up.

All patients had an IDA with IMH and received an endovascular treatment.