Ictal SPECT using an attachable automated injector: clinical usefulness in the prediction of ictal onset zone.
BACKGROUND
Ictal single-photon emission computed tomography (SPECT) is a valuable method for localizing the ictal onset zone in the presurgical evaluation of patients with intractable epilepsy. Conventional methods used to localize the ictal onset zone have problems with time lag from seizure onset to injection.


OBJECTIVE
To evaluate the clinical usefulness of a method that we developed, which involves an attachable automated injector (AAI), in reducing time lag and improving the ability to localize the zone of seizure onset.


METHODS
Patients admitted to the epilepsy monitoring unit (EMU) between January 1, 2003, and June 30, 2008, were included. The definition of ictal onset zone was made by comprehensive review of medical records, magnetic resonance imaging (MRI), data from video electroencephalography (EEG) monitoring, and invasive EEG monitoring if available. We comprehensively evaluated the time lag to injection and the image patterns of ictal SPECT using traditional visual analysis, statistical parametric mapping-assisted, and subtraction ictal SPECT coregistered to an MRI-assisted means of analysis. Image patterns were classified as localizing, lateralizing, and nonlateralizing. The whole number of patients was 99: 48 in the conventional group and 51 in the AAI group.


RESULTS
The mean (SD) delay time to injection from seizure onset was 12.4+/-12.0 s in the group injected by our AAI method and 40.4+/-26.3 s in the group injected by the conventional method (P=0.000). The mean delay time to injection from seizure detection was 3.2+/-2.5 s in the group injected by the AAI method and 21.4+/-9.7 s in the group injected by the conventional method (P=0.000). The AAI method was superior to the conventional method in localizing the area of seizure onset (36 out of 51 with AAI method vs. 21 out of 48 with conventional method, P=0.009), especially in non-temporal lobe epilepsy (non-TLE) patients (17 out of 27 with AAI method vs. 3 out of 13 with conventional method, P=0.041), and in lateralizing the seizure onset hemisphere (47 out of 51 with AAI method vs. 33 out of 48 with conventional method, P=0.004).


CONCLUSIONS
The AAI method was superior to the conventional method in reducing the time lag of tracer injection and in localizing and lateralizing the ictal onset zone, especially in patients with non-TLE.
Lee
Jung-Ju
JJ
Department of Neurology, Eulji General Hospital, Eulji University College of Medicine, Seoul, Korea.
Lee
Sang Kun
SK
Choi
Jang Wuk
JW
Kim
Dong-Wook
DW
Park
Kyung Il
KI
Kim
Bom Sahn
BS
Kang
Hyejin
H
Lee
Dong Soo
DS
Lee
Seo-Young
SY
Kim
Sung Hun
SH
Chung
Chun Kee
CK
Nam
Hyeon Woo
HW
Kim
Kwang Ki
KK
D000293:Adolescent; D000328:Adult; D002648:Child; D004569:Electroencephalography; D004827:Epilepsy / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007267:Injections / Q000295:instrumentation; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019275:Radiopharmaceuticals / Q000008:administration & dosage*; D012189:Retrospective Studies; D019690:Technetium Tc 99m Exametazime / Q000008:administration & dosage; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
D019275:Radiopharmaceuticals; D019690:Technetium Tc 99m Exametazime