Rupture of an intracranial aneurysm causes subarachnoid hemorrhage, a condition with a poor prognosis. While clinical prediction models exist to estimate aneurysm growth and rupture risk, their discrimination is often suboptimal, especially for small aneurysms. Therefore, better predictors are needed to improve patient selection for preventive treatment. Imaging markers that evaluate aneurysm morphology or pathophysiological processes in the aneurysm wall are promising candidates. Consequently, Part I of this thesis explores novel imaging markers of the aneurysm wall for aneurysm growth and rupture. We demonstrate the prognostic potential of three different types of imaging markers for predicting intracranial aneurysm instability: 3D morphologic parameters, aneurysm wall enhancement with gadolinium, and aneurysm wall calcification. Part II focuses on patient-reported outcome measures (PROMs). Patients with unruptured intracranial aneurysms (UIAs) who undergo periodic imaging or preventive treatment often experience anxiety, reduced quality of life, and limitations in workability, factors not represented in traditional clinical outcomes. Capturing PROMs is a critical first step toward improving patient-centered care. The studies in Part II therefore aim to provide a patient-centered perspective on follow-up imaging and image-guided treatment for UIA patients, using the outpatient innovation clinic as a platform to systematically evaluate innovative treatments through routine healthcare data, cohort-embedded trials, and PROMs. We show that two-thirds of UIA patients experience a temporary scan-related increase in stress and anxiety at the time of follow-up imaging (‘scanxiety’), emphasizing the need for timely delivery of scan results. We also report on the outpatient innovation clinic as a platform to systematically evaluate innovative treatments with routine healthcare data, cohort-embedded trials, and PROMs.