Abstracts

There is a wide range of reported values from volumetric studies of the amygdala. The use of single plane thick MRI images may prevent the correct visualization of anatomic landmarks and yield imprecise results. We aimed to assess whether there is significant difference between volumetric analysis of the amygdala performed with single plane MRI 3mm slices and with multiplanar analysis of MRI 1mm slices.
We studied healthy subjects and patients with temporal lobe epilepsy. We performed manual delineation of the amygdala on T1-weighted IR, 3 mm coronal slices and manual delineation of the amygdala on three-dimensional volumetric T1 weighted images with 1 mm slice thickness. The data was compared using dependent t test. Statistic level of significance was set at p[lt]0.05.
Dependent t test showed difference between the volumes obtained by the coronal plane based measurements and the volumes obtained by the three-dimensional analysis of the right and left amygdala among controls (right amygdala t(14)=6.832, p[lt]0.001, left amygdala t(14)=4.814, p[lt]0.001); of the right and left amygdala among patients with right TLE (right amygdala t(5)=2.668, p[lt]0.05, left amygdala t(5)=3.328, p[lt]0.05); and of the right and left amygdala among patients with left TLE (right amygdala t(8)=5.756, p[lt]0.001, left amygdala t t(8)=2.956, p[lt]0.05) .
The incorrect estimative of the amygdala volume may preclude the correct analysis of the biological effects of alterations in the amydgdaloid volume. Te three-dimensional analysis should be preferred because it is based on more extensive anatomical assessment and closer to post-mortem studies.
[Supported by: FAPESP (00/04710-2)]