Postoperative brain MRI
embolic lesions, Microbleeds
BRAIN
Brain MRI will be acquired 1–3 days after the index ablation procedure using a 3 T scanner (MAGNETOM Prisma, Siemens Healthineers; MAGNETOM Vida, Siemens Healthineers; SIGNA Premier, GE Healthcare; Ingenia Elition, Philips Healthcare) with a six‐channel body array coil. The imaging protocol will consist of DWI, T2‐weighted axial fluid‐attenuated inversion recovery (FLAIR), and T2* (T2 star) sequences. The sequence parameters are described in the Supporting Information: For each DWI sequence, the apparent diffusion coefficient (ADC) map will be obtained to prevent overdetection of T2 shine‐through effects on the DWI. The slices and orientation of the DWI and FLAIR sequences will be matched to evaluate the correlation between the DWI and FLAIR images.The number, localization, and size of the SCEs/SCLs will be analyzed.According to the latest recommendations, SCEs/SCLs were defined as below:SCE = diffusion positive (DWI hyperintense) + ADC reduced andSCL = diffusion positive (DWI hyperintense) + ADC reduced + FLAIR positive.Patients with new embolic lesions on the postprocedural MRI will undergo a follow‐up MRI 1 month after CA to assess the lesion progression. Microbleeds will be identified and counted as nodular, strongly hypointense lesions on either the T2*‐weighted or susceptibility‐weighted imaging. All brain MRI images will be independently evaluated by certified radiologists (Yasutoshi Ohta and Tetsuya Fukuda) blinded to the patient characteristics and ablation technology used. If the SCEs and/or SCLs are detected on brain MRI, a neurologist or cardiologist who has been trained in neurology will assess the neurological findings and determine whether they are symptomatic or asymptomatic.