M icroembolic lesions appearing as high signal intensity (HSI) spots on diffusion-weighted imaging (DWI) and restrictive diffusions on the corresponding apparent diffusion coefficient (ADC) maps are often seen following a variety neurovascular procedures. Reportedly, 10% to 76.5% of DWI studies obtained after endovascular coiling of unruptured intracranial aneurysms (UIAs) show such microembolic spots (Fig. 1). [2][3][4]8,9,15,22,[24][25][26] Most patients who show HSI spots are asymptomatic, and the clinical significance of such spots remains controversial. However, the HSI spots reflect the presence of damaged tissue, 5,7,12,15 and their associated potential risks cannot be ignored.This study was conducted to analyze the current incidence of postprocedural DWI HSI lesions at our institution and to explore the possible risk factors for microembolic lesions visible as HSI spots on DWI after endovascular coiling of UIAs.
Methods
Patient PopulationOur local institutional review board approved this retrospective study, and the requirement for patient informed consent for data collection and analyses was waived. We used our neurointerventional database to identify a total of 293 consecutive patients who had presented with a UIA for endovascular treatment between July 2011 and June 2013. Among 293 patients, we excluded 13 patients in whom the aneurysm was treated with parent artery trapping without endosaccular coiling and 2 other patients in whom endovascular management was unsuccessful due to selection aBBreViatiONS ACT = activated clotting time; ADC = apparent diffusion coefficient; BMI = body mass index; DM = diabetes mellitus; DWI = diffusion-weighted imaging; HSI = high signal intensity; PRU = P2Y12 reaction unit; UIA = unruptured intracranial aneurysm. OBJectiVe The incidence and risk factors of microembolic lesions on MR diffusion-weighted imaging (DWI) were analyzed after the endovascular coiling of unruptured intracranial aneurysms (UIAs). MethOdS Data obtained from 271 consecutive patients (70 men and 201 women; median age 57 years; range 23-79 years) who presented with UIA for coil embolization between July 2011 and June 2013 were analyzed. Two independent reviewers examined the DWI and apparent diffusion coefficient maps obtained the following day for the presence of restrictive diffusion spots and counted the number of spots. Multivariate analysis was then performed to identify independent risk factors for developing microembolism following the coiling of an aneurysm. reSultS Microembolic lesions were noted in 101 of 271 patients (37.3%). The results of the multivariate analysis showed that the following factors significantly influenced the risk for microembolism: age, diabetes, previous history of ischemic stroke, high-signal FLAIR lesions in the white matter, multiple aneurysms, and the insertion of an Enterprise stent (all ORs > 1.0 and all p values < 0.05). Previously known risk factors such as prolonged procedure duration, aneurysm size, and decreased antiplatelet function did not show any signific...