MR Imaging in the Presurgical Workup of Patients with Drug-Resistant Epilepsy

Schematic depiction of method used in MR imaging lesion detection.

Focal cortical dysplasia of the Taylor balloon cell type (FCD_BC). Images in a and b show a small lesion in the depth of the left frontal superior sulcus (arrow). Image in c shows a huge lesion and a small lesion (arrow) in the right parietal and occipital lobe. Image in d shows a lesion under an atrophic left superior frontal gyrus. The MR imaging hallmark of FCD_BC is a subcortical hyperintensity tapering toward the lateral ventricle. It is clearly visible (arrow), but because of atrophy of the superior frontal gyrus, the lesion was mistaken for gyral scarring.

Focal polymicrogyria in the left frontal lobe. Contiguous, 3-mm-thick, coronal FLAIR fast spin-echo sections (a–c) show a deep superior frontal sulcus with a slightly irregular contour and a normal signal intensity of the cortex (arrow). Planar surface-reconstructed view (d) generated from a 1.1-mm-thick, 3D, T1-weighted gradient-echo sequence confirms the distorted anatomy (arrow). Histopathologic sections show loss of neocortical architecture (MAP2 [e]) compared with that of adjacent six–layered cortex (nematoxylin–eosin straining [f]).

PXA of the right temporal lobe. The lesion shows typical meningeocerebral contrast enhancement (arrows), cystic parts, and surrounding edema.

Anaplastic (limbic) astrocytoma of WHO grade III. Coronal 3-mm-thick FLAIR fast spin-echo sections show increased volume and signal intensity of both temporopolar cortices, the amygdala, hippocampi, thalami, and left parietal cortex. Because repeated CSF investigation showed a slightly increased protein content (54–95 mg/dL) and 6–8 cells per microliter, limbic encephalitis was suspected.