Flow diverters (FDs) have become a mainstay of endovascular therapy for unruptured intracranial aneurysms (UIAs), yet their implantation carries an inherent risk of ischemic complications. The Pipeline Flex Embolization Device with Shield Technology (PED Shield) and the Lattice Flow Diverter (LFD) are two surface-modified FDs that have shown promising efficacy for mitigating procedure-related ischemic events in prior single-arm or retrospective series. Nevertheless, head-to-head comparative data between these two surface-modified flow diverters remain scarce, and prospective randomized clinical trials are warranted to corroborate their differential performance in lowering ischemic complication risks.This prospective, multicenter randomized controlled trial (RCT) was designed to compare the efficacy of PED Shield versus LFD in reducing ischemic complications after endovascular treatment of UIAs. A total of 196 eligible participants who meet the predefined inclusion and exclusion criteria will be enrolled in the trial. The primary outcome measure is the incidence of new diffusion-weighted imaging (DWI)-positive lesions on brain magnetic resonance imaging (MRI) within 48 hours after the procedure. The secondary outcome measures consist of perioperative symptomatic ischemic events, all-cause mortality and disability rate during the follow-up period, delayed aneurysm rupture at the 6-month follow-up, complete aneurysm occlusion rate, incidence of major in-stent stenosis (stenosis degree >50%) at the 6-month follow-up, and the number of new DWI-positive lesions within 48 hours post-procedure.

Inclusion Criteria:

1. Patients were diagnosed with unruptured intracranial aneurysms, and the lesions were evaluated to be suitable for endovascular treatment with flow diverter devices (PED Shield/Lattice).
2. During the study period, only one target aneurysm per patient was treated, with the exception of segmental lesions, in which multiple aneurysms located within the same arterial segment were treated with a single or overlapping study devices.
3. The target aneurysm was treated solely with flow diverter (FD) implantation in the current study.
4. The age of enrolled patients ranged from 18 to 75 years old.
5. Patients were capable of understanding the study-related informed consent information and provided written informed consent for the use of their clinical data for research purposes.

Exclusion Criteria:

1. Patients with a prior history of endovascular treatment for the target aneurysm.
2. Patients in the acute stage of cerebrovascular diseases (acute cerebral infarction or intracerebral hemorrhage with an onset time of ≤ 2 weeks).
3. Patients complicated with other cerebrovascular disorders, including moyamoya disease, cerebrovascular malformations, and arteriovenous fistula.
4. Patients with atherosclerotic changes in the parent artery of the target aneurysm that necessitated additional intraoperative endovascular interventions (e.g., balloon angioplasty or conventional stent implantation).
5. Patients with a preoperative modified Rankin Scale (mRS) score greater than 2.
6. Patients with any absolute contraindications to device treatment as specified in the Instructions for Use (IFU).
7. Patients enrolled in other clinical trials that may interfere with the primary or secondary endpoints of the present study.
8. Patients with comorbidities that may interfere with neurological function evaluation, affect survival status, or impair the ability to complete follow-up visits.
9. Pregnant or lactating female patients.