Incidence and risk factors for diffusion-weighted imaging (+) lesions after intracranial stenting and its relationship with symptomatic ischemic complications

Background and Purpose-Little is known about high-signal lesions in magnetic resonance diffusion-weighted imaging (DWI [+]) after stenting for intracranial atherosclerotic stenosis. This study aimed to evaluate the incidence, distribution, risk factors, and clinical implications of DWI (+) after intracranial stenting. Methods-A total of 123 patients (male:female=88:35, mean age, 64.1 years) with symptomatic intracranial atherosclerotic stenosis (mean stenosis, 76.1±7.7%) underwent both stenting and poststenting DWI. The incidence, distribution (embolicalone versus stenosis-associated perforator/mixed), and risk factors of DWI (+) and its relationship with symptomatic ischemic complications (SIC, including stroke or transient ischemic attack) were retrospectively evaluated. Results-Forty-three patients (35.0%) had DWI (+). Middle cerebral artery, smaller distal parent artery, and treatmentrelated dissection were independent risk factors for DWI (+) (P<0.05). SIC occurred in 4 patients (3.3%), all of whom had DWI (+). Of the patients with DWI (+), neither the number nor the volume of DWI (+) differed significantly between SIC and asymptomatic patients: median number/patient, 3.5 (range, 2-11) versus 2.0 (range, 1-11) and median volume/ patient, 329.8 mm3 (range, 76-883.5 mm3) versus 119.5 mm3 (range, 32.5-873.0 mm3). However, SIC occurred more frequently in the stenosis-associated perforator/mixed type (3/11, 27.3%) than in the embolic-alone type (1/32, 3.1%; P<0.05). Conclusions-The incidence of DWI (+) after intracranial stenting for intracranial atherosclerotic stenosis was 35.0%. Middle cerebral artery, smaller distal parent artery, and treatment-related dissection were independent risk factors for DWI (+). SIC occurred more frequently in the stenosis-associated perforator/mixed type than in the embolic-alone type.