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Am J Nucl Med Mol Imaging 2012;2(3):335-343
Original Article
Impact of expectation-maximization reconstruction iterations on the diagnosis of
temporal lobe epilepsy with PET
John M Floberg, Aaron F Struck, Brooke K Peters, Christine J Jaskowiak, Scott B Perlman, Lance T Hall
Department of Medical Physics; Department of Neurology; Department of Radiology, University of Wisconsin-Madison, Madison, WI,
USA
Received April 26, 2012; accepted May 17, 2012; Epub July 10, 2012; Published July 30, 2012
Abstract: There is a well known tradeoff between image noise and image sharpness that is dependent on the number of iterations
performed in ordered subset expectation maximization (OSEM) reconstruction of PET data. We aim to evaluate the impact of this
tradeoff on the sensitivity and specificity of 18F-FDG PET for the diagnosis of temporal lobe epilepsy. A retrospective blinded readers
study was performed on two OSEM reconstructions, using either 2 or 5 iterations, of 32 18F-FDG PET studies acquired at our
institution for the diagnosis of temporal lobe epilepsy. The sensitivity and specificity of each reconstruction for identifying patients
who were ultimately determined to be surgical candidates was assessed using an ROC analysis. The sensitivity of each
reconstruction for identifying patients who showed clinical improvement following surgery was also assessed. Our results showed
no significant difference between the two reconstructions studied for either the sensitivity and specificity of 18F-FDG PET for
predicting surgical candidacy, or its sensitivity for predicting positive surgical outcomes. This implies that the number of iterations
performed during OSEM reconstruction will have little impact on a reader based interpretation of 18F-FDG PET scans acquired for
the diagnosis of temporal lobe epilepsy, and can be determined by physician and institutional preference. (ajnmmi1204001)
Keywords: 18F-FDG PET, temporal lobe epilepsy, OSEM reconstruction, ROC analysis
Address all correspondence to:
Dr. John M Floberg
Department of Medical Physics
University of Wisconsin-Madison
Madison, WI, USA.
E-mail: jfloberg@wisc.edu
Original Article
Impact of expectation-maximization reconstruction iterations on the diagnosis of
temporal lobe epilepsy with PET
John M Floberg, Aaron F Struck, Brooke K Peters, Christine J Jaskowiak, Scott B Perlman, Lance T Hall
Department of Medical Physics; Department of Neurology; Department of Radiology, University of Wisconsin-Madison, Madison, WI,
USA
Received April 26, 2012; accepted May 17, 2012; Epub July 10, 2012; Published July 30, 2012
Abstract: There is a well known tradeoff between image noise and image sharpness that is dependent on the number of iterations
performed in ordered subset expectation maximization (OSEM) reconstruction of PET data. We aim to evaluate the impact of this
tradeoff on the sensitivity and specificity of 18F-FDG PET for the diagnosis of temporal lobe epilepsy. A retrospective blinded readers
study was performed on two OSEM reconstructions, using either 2 or 5 iterations, of 32 18F-FDG PET studies acquired at our
institution for the diagnosis of temporal lobe epilepsy. The sensitivity and specificity of each reconstruction for identifying patients
who were ultimately determined to be surgical candidates was assessed using an ROC analysis. The sensitivity of each
reconstruction for identifying patients who showed clinical improvement following surgery was also assessed. Our results showed
no significant difference between the two reconstructions studied for either the sensitivity and specificity of 18F-FDG PET for
predicting surgical candidacy, or its sensitivity for predicting positive surgical outcomes. This implies that the number of iterations
performed during OSEM reconstruction will have little impact on a reader based interpretation of 18F-FDG PET scans acquired for
the diagnosis of temporal lobe epilepsy, and can be determined by physician and institutional preference. (ajnmmi1204001)
Keywords: 18F-FDG PET, temporal lobe epilepsy, OSEM reconstruction, ROC analysis
Address all correspondence to:
Dr. John M Floberg
Department of Medical Physics
University of Wisconsin-Madison
Madison, WI, USA.
E-mail: jfloberg@wisc.edu
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