Measurement of temporal asymmetries of glucose consumption using linear profiles: reproducibility and comparison with visual analysis.
OBJECTIVE
One approach to regionally analyze temporal glucose consumption consists in drawing linear profiles over the maximal values measured in the temporal cortical ribbon. The aim of our study was to test the reproducibility of this method and to compare its diagnostic performance to that of visual analysis in patients with complex partial seizures (CPS).


METHODS
Regional cerebral glucose consumption (rCMRGIc) was measured interictally in 25 CPS patients and 10 controls using F-18-deoxyglucose and the positron emission tomography (PET) camera ECAT EXACT 47. The PET scans were visually analyzed for the occurrence of unilateral temporal hypometabolism. Furthermore, rCMRGIc was quantified on six contiguous coronal planes by manually tracing maximal values of temporal glucose consumption, thus creating line profiles of temporal glucose consumption for each side. Indices of asymmetry (ASY) were then calculated from these line profiles in four temporal regions and compared to the corresponding 95% confidence intervals of the control data. All analyses were performed by two observers independently from each other and without knowledge of the clinical findings.


RESULTS
The agreement between the two observers with regard to focus lateralization was 96% (kappa = 0.93) on visual analysis and 100% (kappa = 1) on quantitative analysis. There was an excellent agreement with regard to focus lateralization between visual and quantitative evaluation (kappa = 0.8).


CONCLUSIONS
Quantitation of local temporal rCMRGIc by using linear profile analysis is highly reproducible; for the lateralization of epileptogenic foci, however, this method does not possess significant advantages over the visual evaluation of the scans.
Matheja
P
P
Kliniken und Polikliniken für Nuklearmedizin, Westfälische Wilhelms-Universität Münster, Deutschland.
Diehl
B
B
Kuwert
T
T
Stodieck
S R
SR
Schäfers
M
M
Schäfers
K
K
Schuierer
G
G
Ringelstein
E B
EB
Schober
O
O
D000328:Adult; D000368:Aged; D016001:Confidence Intervals; D004569:Electroencephalography; D017029:Epilepsy, Complex Partial / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000378:metabolism*; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D007839:Functional Laterality; D015902:Gamma Cameras; D005947:Glucose / Q000378:metabolism*; D006019:Glycolysis; D006624:Hippocampus / Q000000981:diagnostic imaging / Q000378:metabolism; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D012039:Regional Blood Flow; D015203:Reproducibility of Results; D013702:Temporal Lobe / Q000000981:diagnostic imaging* / Q000378:metabolism; D014055:Tomography, Emission-Computed / Q000379:methods
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D005947:Glucose