LESION SIZE EVALUATION BY STATISTICAL PARAMETRIC MAPPING PROGRAM IN SIMULATED EPILEPTIC BRAIN.

Abstract

Several simulations of SPECT ictal and inter-ictal studies were performed in order to test the ability of SPM program for detection of brain lesion size and to determine the effect of site for size detection. Three cylindrical artificial lesions of diameters and length of 14x7 mm., 9x5 mm., and 4x5 mm. were positioned in 3 different regions [anterior cingulate cortex, posterior cingulate cortex, deep gray matter (basal ganglia)] in the brain phantom. Triple-headed SPECT acquisition of simulated ictal and inter-ictal states were carried out. All data were transferred to SPM2 program, which detected cluster volumes for each size and site were compared to actual lesion volumes. SPM could detect 14 mm lesion sizes at all sites. The 9 mm lesions were detected at anterior and basal ganglia sites. The 4 mm lesion was only detected at the anterior and basal ganglia site and the volume detected by SPM is larger than the true volume. In conclusion, size detected by SPM is much larger than the actual size. Sites of lesions may affect size detection.