MRI-negative epilepsy: A systematic review and meta-analysis.

Area of Science:

• Neurology
• Radiology
• Epileptology

Background:

• Drug-resistant focal epilepsy is often categorized as MRI-positive or MRI-negative based on lesion visibility.
• The criteria for classifying epilepsy as MRI-negative are inconsistent across studies.
• This ambiguity impacts diagnostic accuracy and treatment strategies.

Purpose of the Study:

• To systematically review and synthesize evidence regarding the designation of MRI-negative epilepsy.
• To assess the consistency of reporting imaging parameters, rater expertise, and post-processing in studies of MRI-negative epilepsy.
• To evaluate the impact of MRI post-processing on diagnostic yield and surgical outcomes.

Main Methods:

• A systematic review and meta-analysis adhering to PRISMA guidelines (1990-2025) was conducted.
• Studies were identified across Embase, Cochrane, and Medline databases.
• Unsupervised clustering stratified studies by imaging modalities; meta-analyses assessed post-processing effects and MRI-negative status on outcomes.

Main Results:

• 246 articles were included, encompassing 10,463 MRI-negative and 7,436 MRI-positive patients.
• MRI-negative patients underwent SEEG more frequently but had less frequent surgery and less favorable outcomes.
• Clustering revealed distinct study classes based on imaging modality reporting and expertise; post-processing yielded a 39% gain in diagnostic yield.

Conclusions:

• The classification of MRI-negative epilepsy lacks standardized criteria, with frequent omissions in reporting imaging parameters and reader expertise.
• Systematic MRI post-processing is essential for improving diagnostic yield and should be a routine part of multimodal epilepsy evaluations.
• Accurate classification is critical for optimizing epilepsy surgery and patient outcomes.