Objective:To explore the clinical and imaging characteristics of patients with unruptured intracranial aneurysms accompanied by sentinel headache.Methods:Forty patients with unruptured intracranial aneurysms confirmed by DSA/CTA and accompanied by sentinel headache admitted to Department of Neurology, First Affiliated Hospital of Xiangnan University from January 2018 to August 2023 were selected as the study subjects; the clinical and imaging characteristics of these patients were summarized. Forty-four patients with unruptured intracranial aneurysms without sentinel headache and 40 patients with subarachnoid hemorrhage caused by ruptured intracranial aneurysms admitted to the hospital at the same period were selected as controls. The differences in aneurysm length (maximum diameter), morphology, tumor length (maximum diameter)/neck width (AR), and risk score for rupture of intracranial aneurysms (scores of population, hypertension, age, size of aneurysm, earlier aneurysm rupture, site of aneurysm [PHASES]) among the 3 groups were analyzed.Results:Among the 40 patients with unruptured intracranial aneurysms accompanied by sentinel headache, 20 (50%) presented with pain localized at the lateral frontal and orbital regions, 3 (7.5%) with pain at the posterior neck region, and 17 (42.5%) with irregular headache sites; 34 (85%) had new onset headache, and 6 (15%) had changes in headache nature besides chronic headache; 24 patients (60%) had posterior communicating artery aneurysm, 12 (30%) had internal carotid artery aneurysm, 1 (2.5%) had middle cerebral artery aneurysm, and 3 (7.5%) had vertebral artery dissection aneurysm; 36 (90%) had irregular aneurysm morphology. Compared with patients with unruptured intracranial aneurysms without sentinel headache, patients with unruptured intracranial aneurysms accompanied by sentinel headache and those with subarachnoid hemorrhage caused by ruptured intracranial aneurysms had larger aneurysm length (maximum diameter), higher proportion of irregular morphology, higher AR value, and higher PHASES scores, with significant differences ( P<0.05). Compared with patients with subarachnoid hemorrhage caused by ruptured intracranial aneurysms, patients with unruptured intracranial aneurysms accompanied by sentinel headache had larger aneurysm length (maximum diameter) and higher PHASES scores, with significant differences ( P<0.05). Conclusion:Sentinel headache is common in patients with unruptured posterior communicating artery aneurysms, and the relatively specific headache pattern is sudden periorbital pain or posterior neck pain; patients with unruptured intracranial aneurysms accompanied by sentinel headache have a higher rupture risk due to the larger size, more irregular shape, higher AR value of the aneurysm, therefore, same attention should be payed to these patients as those with ruptured aneurysms in clinical practice.