Prospective use of subtraction ictal SPECT coregistered to MRI (SISCOM) in presurgical evaluation of XXXX .

@entity1 @entity410 @entity302
PURPOSE: In @entity1 with drug-refractory focal @entity302 , nonlesional magnetic resonance imaging (MRI) or discordant data of presurgical standard investigations leads to failure generating a sufficient hypothesis for electrode implantation or @entity302 surgery. The @entity410 -onset zone can be further investigated by subtraction ictal single-photon emission computed tomography (SPECT) coregistered to MRI (SISCOM). This is an observational study of a large consecutive cohort of @entity1 undergoing prospective SISCOM to generate hypothesis for electrode implantation or site of @entity302 surgery. METHODS: One hundred seventy-five consecutive @entity1 undergoing presurgical evaluation with either nonlesional MRI or discordant data of standard investigations preventing the generation of hypothesis for @entity410 onset were evaluated with SISCOM. Results were compared to gold standard for @entity410 onset detection, either electrocorticography (ECoG) and/or postoperative outcome. KEY FINDINGS: One hundred thirty @entity1 had successful SPECT injection. Hypothesis for electrode implantation/site of surgery was generated in 74 @entity1 . Forty @entity1 had gold standard comparison. Twenty-eight @entity1 underwent resective surgery. SISCOM was concordant to site of surgery in 82%. An additional 12 @entity1 underwent invasive EEG monitoring but were not suitable for surgery. SISCOM was concordant multifocal in 75%. Two years postsurgical follow-up of 26 @entity1 showed favorable outcome in 22 (Engel class I and class II). SIGNIFICANCE: SISCOM is a highly valuable diagnostic tool to localize the @entity410 -onset zone in nonlesional and extratemporal @entity302 . Outcome in this @entity1 group was unexpectedly good, even in @entity1 with nonlesional MRI. The high correlation with ECoG and site of successful surgery is a strong indicator that outcome prediction in this @entity1 group should be adapted accordingly, which may encourage more @entity1 to undergo electrode implantation and subsequent successful surgery. Statistical analysis showed that SISCOM with shorter duration of @entity410 , focal @entity410 , and lesional MRI was more likely to generate implantation hypothesis.
