More than 1.5 million people are diagnosed with refractory epilepsy annually, with resective surgery being the most promising treatment option [1,2]. However, the surgery outcomes are not currently satisfying, and an unclear definition of the Epileptic Zone (EZ) is one of the reasons [3]. Patients without clear MRI lesions (MR-negative) are the most challenging and tend to be excluded from the surgery [4]. 7 Tesla (7T) MRI offers potential benefits of more accurate imaging and automated analysis of its images can provide further information for presurgical evaluations due to higher resolution [5]. To this end, we compared the performance of 3T and 7T T1w MRI data for automated DL-driven segmentation using SynthSeg [6] in a cohort of 22 MR-negative patients. After segmenting images into 33 regions we calculated the volumes in each region for each patient and compared the percentual volume differences. 7T resolution was 0.75mm compared to 1mm at 3T. Table 1 presents that at 7T, the median volume for total intracranial volume is 4.86% smaller than at 3T. One cause is B1-inhomogeneity at the skull base, which is a common occurrence [7]. Also, the cerebrospinal fluid (CSF) has a greater volume in 7T images, as 7T voxelsize is 42% of 3T’s. These results are a step towards better analysis of new 7T modalities like MRSI, and also proof of feasible regions-wise quantitative investigations in future studies that should lead to a better understanding of epileptogenicity and improved treatment strategies.RegionsMedian 7T (ml)Median 3T (ml)(7T-3T)/7T (%)left subcortical grey matter25.3526.82-5.80left cerebral white matter209.62228.82-9.16left cerebral cortex239.78273.17-13.93left hippocampus4.124.23-2.69right subcortical grey matter25.6427.21-6.13right cerebral white matter209.97222.50-5.97right cerebral cortex239.92272.24-13.47right hippocampus4.244.015.32total intracranial1,426.231,499.12-5.11