HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Niimura, K. Articles by Chugani, H. T. Search for Related Content PubMed PubMed Citation Articles by Niimura, K. Articles by Chugani, H. T.

[¹¹C]Flumazenil PET: Activity Images Versus Parametric Images for the Detection of Neocortical Epileptic Foci

Departments of Pediatrics, Neurology and Radiology, Children's Hospital of Michigan and Detroit Medical Center, Wayne State University School of Medicine, Detroit, Michigan

Correspondence: For correspondence or reprints contact: Otto Muzik, PhD, Department of Radiology/PET Center, Children's Hospital of Michigan, 3901 Beaubien Blvd., Detroit, MI 48201.

ABSTRACT

[¹¹C]flumazenil (FMZ) imaged with PET allows the computation of parametric images of both tracer influx (K1) and volume of distribution (VD). The VD images, which allow visualization of a quantitative measure of benzodiazepine receptor binding, are reported to have high sensitivity and specificity for the delineation of epileptic foci. However, the clinical feasibility of this method is compromised by the necessity of arterial blood sampling. We therefore compared the performance of parametric VD images against simple FMZ activity images for the detection of neocortical epileptic foci. Methods: FMZ PET data from 7 children with extratemporal lobe epilepsy (mean age [± SD]9.8 ± 4.4 y) and 6 healthy adult volunteers (mean age [± SD]40 ± 8 y) were analyzed using a semiautomated analysis algorithm. FMZ activity images and parametric VD images were analyzed for asymmetry with cut off thresholds of 8%, 10% and 12%. Results: The time frame between 10 and 20 min after injection represented overall the best agreement between FMZ activity and VD images independent of the threshold. The normal asymmetry in VD images was determined as 6.4% ± 1.4% and was significantly higher in the FMZ activity images (7.6% ± 1.4%, P = 0.001). Increasing the cutoff threshold resulted in a significant decrease in the area defined as abnormal in both the VD and the FMZ activity images. Abnormalities defined in FMZ activity images identified additional brain regions as abnormal at the 8% threshold, but there was good agreement with VD images at the 10% asymmetry threshold. In those regions where abnormalities in VD and FMZ activity images were not matched, the asymmetry indices obtained from K1 images were significantly higher than those derived from the VD images (P = 0.01). Conclusion: Differences between VD and activity images above the 8% threshold are mainly due to K1. Abnormalities defined in FMZ activity images using a threshold of 10% agree well with those obtained from parametric VD images, indicating that activity images obtained from the time frame of 10–20 min are essentially equivalent to VD images with regard to detection of regions of abnormality for seizure focus localization.

Key Words: PET • epilepsy • flumazeni • benzodiazepine receptor • activity image • parametric image • volume of distribution

This article has been cited by other articles:

				C. Juhasz, D. C. Chugani, O. Muzik, A. Shah, J. Shah, C. Watson, A. Canady, and H. T. Chugani Relationship of flumazenil and glucose PET abnormalities to neocortical epilepsy surgery outcome Neurology, June 26, 2001; 56(12): 1650 - 1658. [Abstract] [Full Text] [PDF]

				C. Juhasz, D. C. Chugani, O. Muzik, C. Watson, J. Shah, A. Shah, and H. T. Chugani Electroclinical correlates of flumazenil and fluorodeoxyglucose PET abnormalities in lesional epilepsy Neurology, September 26, 2000; 55(6): 825 - 835. [Abstract] [Full Text] [PDF]