American Journal of Roentgenology, Vol 163, 1453-1457, Copyright © 1994 by American Roentgen Ray Society
MR measurements of the hippocampus for lateralization of temporal lobe epilepsy: value of measurements of the body vs the whole structure
JH Kim, RD Tien, GJ Felsberg, AK Osumi and N Lee
Department of Radiology (Section of Neuroradiology), Duke University Medical Center, Durham, NC 27710.
OBJECTIVE. Measurements of the volume of the hippocampus have been used
preoperatively to determine the side of the hippocampus involved in
patients with intractable temporal lobe epilepsy. However, the method used
is time consuming and requires special training. The purpose of this study
was to determine the validity of using measurements of the volume of the
hippocampal body as a substitute for measurements of the volume of the
whole hippocampus in patients with temporal lobe epilepsy. SUBJECTS AND
METHODS. The study group consisted of 33 patients with intractable temporal
lobe epilepsy due to presumed hippocampal sclerosis and 30 control
subjects. Of the 33 patients with intractable temporal lobe epilepsy, 30
had hippocampal sclerosis and three had normal findings on pathologic
examination of the hippocampus. T2-weighted fast spin-echo images were used
to determine hippocampal volumes. Volumes were calculated by summing the
sectional areas of the entire hippocampus and of the hippocampal body.
Correlation between the volume of the hippocampal body and the volume of
the whole hippocampus was determined. The sensitivity and specificity of
measurement of the volume of the hippocampal body for lateralizing the foci
responsible for seizures in patients with presumed hippocampal sclerosis
were compared with those of measurement of the volume of the whole
hippocampus. RESULTS. Significant linear relationships were noted between
volumes of the hippocampal body and volumes of the whole hippocampus (p
< .001). The sensitivity and specificity of measurements of volumes of
the hippocampal body were identical to those of measurements of volumes of
the whole hippocampus (87% and 100%, respectively). CONCLUSIONS. Our
results show that segmental MR measurements of the body of the hippocampus
are as accurate as measurements of the whole hippocampus for lateralizing
temporal lobe epilepsy before surgery. Because segmental measurements are
less time consuming and require less experience to perform, they are
considered the procedure of choice.