Abstract 384: Rapid accumulation of spontaneous intracranial dissection cases within two years

Introduction Spontaneous intracranial dissection is very uncommon and there are few cases reported so far. Interestingly most cases reported are from Asia. Genetic perspective would be one of the speculative causes. Making a definite diagnosis is also one of the pitfalls and distinguishing from other more common diseases, intracranial atherosclerosis which is also much more prevalent in Asia is sometimes difficult. With such a limited case, clinical progression and appropriate treatment would possibly be hard to define. Method We present a series of 11 cases directed or transferred to our hospital referral center from 2022‐2024. All patient information retrospectively collected in demographic, clinical presentation, and radiologic workups including relevant investigation, treatment, and clinical outcomes were described. Outcome All patients are between 29 and 82 years old with the six decades being the most prevalent composed of 8 cases of middle cerebral artery dissection, M1 segment and one case of M2 segment of middle cerebral artery dissection, one case of anterior cerebral artery dissection, and one case of posterior cerebral artery dissection, P2 segment. These cases have intracranial dissection spontaneously, there are no connective tissue disorders related to physical examination and there is no history of head injury before the event. Most of them present with acute ischemic stroke or transient ischemic attack and a few of them with headaches from subarachnoid hemorrhage. Interestingly there is another case that has transient ischemic attack and hyperkinetic movement disorders. Magnetic resonance imaging or cerebral angiogram reveals an intimal flap, double lumen, or string sign in all cases. These findings could distinguish from intracranial atherosclerosis if looked at carefully. The case of M2 segment middle cerebral artery dissection shows rapid progressive change in the dissecting aneurysm. Most of them had no anterograde flow impairment therefore these cases received antiplatelet treatment but four cases (36%) present with acute large vessel occlusion or severe stenosis received endovascular treatment and two of them ended up with rescue permanent stenting. One of two cases who has subarachnoid hemorrhage receives surgical clipping and bypass. All cases presenting with ischemic stroke have good clinical outcomes at three months follow up including cases with subarachnoid hemorrhage. Conclusion Spontaneous intracranial dissection is uncommon and underdiagnosed. Differentiating from intracranial atherosclerosis is important, and recognizing intracranial dissection features is useful. Clinical features or progression may not be benign since some of them may present with acute large vessel occlusion or stenosis. Providing treatment in this type is very challenging otherwise complications from endovascular treatment may be devastating.