Alterations of apparent diffusion coefficient from ultra high b‐values in the bilateral thalamus and striatum in MRI‐negative drug‐resistant epilepsy

Objective Subcortical nuclei such as the thalamus and striatum have been shown to be related to seizure modulation and termination, especially in drug‐resistant epilepsy. Enhance diffusion‐weighted imaging (eDWI) technique and tri‐component model have been used in previous studies to calculate apparent diffusion coefficient from ultra high b‐values (ADCuh). This study aimed to explore the alterations of ADCuh in the bilateral thalamus and striatum in MRI‐negative drug‐resistant epilepsy. Methods Twenty‐nine patients with MRI‐negative drug‐resistant epilepsy and 18 healthy controls underwent eDWI scan with 15 b‐values (0–5000 s/mm2). The eDWI parameters including standard ADC (ADCst), pure water diffusion (D), and ADCuh were calculated from the 15 b‐values. Regions‐of‐interest (ROIs) analyses were conducted in the bilateral thalamus, caudate nucleus, putamen, and globus pallidus. ADCst, D, and ADCuh values were compared between the MRI‐negative drug‐resistant epilepsy patients and controls using multivariate generalized linear models. Inter‐rater reliability was assessed using the intra‐class correlation coefficient (ICC) and Bland–Altman (BA) analysis. False discovery rate (FDR) method was applied for multiple comparisons correction. Results ADCuh values in the bilateral thalamus, caudate nucleus, putamen, and globus pallidus in MRI‐negative drug‐resistant epilepsy were significantly higher than those in the healthy control subjects (all p