Seizure-onset zone localization by statistical parametric mapping in visually normal (18) F-FDG PET studies.
Neuroimaging is crucial in the presurgical evaluation of patients with medically refractory epilepsy. To improve the moderate sensitivity of [(18) F]fluorodeoxyglucose-positron emission tomography ((18) F-FDG-PET), our aim was to evaluate the usefulness of statistical parametric mapping (SPM) to localize the seizure-onset zone (SOZ) in PET studies deemed normal by visual assessment.



Fifty-five patients with medically refractory epilepsy whose (18) F-FDG-PET was visually evaluated as normal were retrospectively included. Twenty of these patients had undergone surgical intervention. PET images were analyzed by SPM8 using a corrected p-value of p < 0.05 and three uncorrected p-values of p < 0.0001, p < 0.001, and p < 0.005, matched with minimum cluster sizes of k > 0, k > 20, k > 100, and k > 200, respectively. The SPM-identified potential seizure zone (SZ) was compared to the SOZ, which was determined by consensus during patient management meetings in the epilepsy unit, taking into account presurgical tests. Studies in which the SPM-identified potential SZ was concordant with the SOZ were considered "correctly localizing."



The SPM threshold combination with the least restrictive p-value and greatest minimum cluster size achieved the highest rate of correctly localizing studies. When p < 0.005/k > 200 was used, 40% (22/55) of studies were correctly localizing, and the concordance obtained in the surgically intervened subgroup was substantial (к = 0.607, 95% confidence interval [CI] 0.258-0.957), which was comparable to the concordance obtained by magnetic resonance imaging (MRI) (к = 0.783, 95% CI 0.509-1.000).



SPM offers improved SOZ localization in (18) F-FDG-PET studies that are negative on visual assessment. For this purpose, statistical parametric maps could be thresholded with liberal p-values and restrictive cluster sizes.
Nuclear Medicine Department, Hospital Clinic, Barcelona, Spain.
Maria
M
Mayoral
Biomedical Imaging Group, Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Barcelona, Spain.|Biophysics and Bioengineering Unit, Physiological Sciences Department I, School of Medicine, University of Barcelona, Spain.
Berta
B
Marti-Fuster
Neurology Department, Hospital Clinic, Barcelona, Spain.|August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Barcelona, Spain.
Mar
M
Carreño
Biostatistics, Public Health Department, School of Medicine, University of Barcelona, Barcelona, Spain.
Josep L
JL
Carrasco
August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Barcelona, Spain.|Radiology Department, Hospital Clinic, Barcelona, Spain.
Núria
N
Bargalló
Neurology Department, Hospital Clinic, Barcelona, Spain.|August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Barcelona, Spain.
Antonio
A
Donaire
Neurosurgery Department, Hospital Clinic, Barcelona, Spain.
Jordi
J
Rumià
Nuclear Medicine Department, Hospital Clinic, Barcelona, Spain.
Andrés
A
Perissinotti
Nuclear Medicine Department, Hospital Clinic, Barcelona, Spain.|August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Barcelona, Spain.
Francisco
F
Lomeña
August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Barcelona, Spain.|Psychiatry and Psychology Department, Hospital Clinic, Barcelona, Spain.
Luis
L
Pintor
August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Barcelona, Spain.|Psychiatry and Psychology Department, Hospital Clinic, Barcelona, Spain.
Teresa
T
Boget
Nuclear Medicine Department, Hospital Clinic, Barcelona, Spain.|Biomedical Imaging Group, Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Barcelona, Spain.|August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Barcelona, Spain.
Xavier
X
Setoain
D000328:Adult; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000000981:diagnostic imaging*; D000069279:Drug Resistant Epilepsy / Q000000981:diagnostic imaging* / Q000601:surgery; D004569:Electroencephalography; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals / Q000378:metabolism; D055815:Young Adult
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
Epilepsy; PET; SPM