Purpose: To assess the biochemical properties of band heterotopia in comparison with other cortical developmental malformations (CDMs) by using proton magnetic resonance spectroscopy (1H-MRS).
Methods: We performed localized single-voxel 1H-MRS studies on 13 patients [five band heterotopia (BH), two focal cortical dysplasia (CD), two unilateral CD, one bilateral perisylvian dysplasia, three hemimegalencephaly]. CDMs other than BH were categorized as CD. Spectra were acquired from volumes of interest (VOIs) localized in the CD and in normal-appearing cortex on the contralateral side. In BH patients, the VOIs were the external cortex and the laminar heterotopia. For the BH study, spectra also were obtained from the cortex of age-matched normal volunteers.
Results: The spectra of CD lesions were characterized by significantly lower ratios of N-acetyl aspartate to creatine (NAA/Cr) and by higher choline to Cr (Cho/Cr) ratios than in the contralateral remote cortex (p = 0.01 and 0.01, respectively). The NAA/Cr and Cho/Cr ratios of the external cortex of BH were not significantly different from those of normal volunteers. The NAA/Cr ratio of the laminar heterotopia was not significantly different from that of the external cortex (p = 0.12) or normal volunteers (p = 0.60), whereas Cho/Cr was significantly higher in laminar heterotopias than in the external cortex (p = 0.04) or controls (p = 0.03).
Conclusions: 1H-MRS can distinguish between the metabolic properties of BH and CD.