Impact of an optimized epilepsy surgery imaging protocol for focal epilepsy: a monocentric prospective study

Objective: To evaluate in a real clinical scenario the impact of the ILAE-recommended "Harmonized neuroimaging of epilepsy structural sequences"- HARNESS protocol in patients affected by focal epilepsy. Methods: We prospectively enrolled focal epilepsy patients who underwent a structural brain MRI between 2020-2021 at Modena University Hospital. For all patients, MRIs were: a) acquired according to the HARNESS-MRI protocol (H-MRI); b) reviewed by the same neuroradiology team. MRI outcomes measures were: the number of positive (diagnostic) and negative MRI; the type of radiological diagnosis classified in: 1. Hippocampal Sclerosis; 2. Malformations of cortical development (MCD); 3. Vascular malformations; 4. Glial scars; 5. Low-grade epilepsy-associated tumours; 6. Dual pathology. For each patient we verified for previous MRI (without HARNESS protocol, noH-MRI) and the presence of clinical information in the MRI request form. Then the measured outcomes were reviewed and compared as appropriate. Results: A total of 131 patients with H-MRI were included in the study. 100 patients out from this cohort had at least one previous noH-MRI scan. Of those, 92/100 were acquired at the same Hospital than H-MRI and 71/92 on a 3T scanner. The HARNESS protocol revealed 81 (62%) positive and 50 (38%) negative MRI, and MCD was the most common diagnosis (60%). Among the entire pool of 100 noH-MRI, 36 resulted positive with a significant difference (p<.001) compared to H-MRI. Similar findings were observed when accounting for the expert radiologists (H-MRI= 57 positive; noH-MRI=33, p<.001) and the scanner field strength (H-MRI 43=positive, noH-MRI=23, p<.001), while clinical information were more present in H-MRI (p<.002). Significance: The adoption of a standardized and optimized MRI acquisition protocol together with adequate clinical information contribute to identify a higher number of potentially epileptogenic lesions (especially FCD) thus impacting concretely on the clinical management of patients with focal epilepsy.