Lc. Meiners et al., TEMPORAL-LOBE EPILEPSY - THE VARIOUS MR APPEARANCES OF HISTOLOGICALLYPROVEN MESIAL TEMPORAL SCLEROSIS, American journal of neuroradiology, 15(8), 1994, pp. 1547-1555
Citations number
29
Categorie Soggetti
Neurosciences,"Radiology,Nuclear Medicine & Medical Imaging
PURPOSE: To determine the frequency of appearance of various MR signs
in mesial temporal sclerosis, to determine the optimal scanning planes
for their visualization, and to propose a histologic explanation for
the diminished demarcation between gray and white matter in the tempor
al lobe, a frequent MR finding in patients with mesial temporal sclero
sis. METHODS: MR scans of 14 surgically treated patients with epilepsy
and histologically proven mesial temporal sclerosis were assessed for
the presence of six features: feature 1, high signal intensity in the
hippocampus; 2, reduced hippocampal size; 3, ipsilateral atrophy of t
he hippocampal collateral white matter; 4, enlarged temporal horn; 5,
reduced gray-white matter demarcation in the temporal lobe; and 6, dec
reased temporal lobe size. RESULTS: Feature 1 was present in 14 patien
ts and was best appreciated on the T2-weighted images in planes parall
el to the long axes of the hippocampi. Feature 2, present in 12 patien
ts, and feature 6, present in 9 patients, were optimally seen in the c
oronal planes and on the inversion-recovery sequences in particular. F
eature 3, present in 12 patients, was optimally seen on the coronal T2
-weighted images. Feature 4, seen in 11 patients, was equally well see
n in all planes (transverse, coronal, and parallel to the long axes of
the hippocampi). Feature 5, seen in 10 patients, was best appreciated
on the T2-weighted images in the planes of the long axes of the hippo
campi. Histologic investigation of the temporal lobe white matter in t
he 10 patients with feature 5 demonstrated on the MR scan showed abnor
malities in 7 cases. Oligodendroglia cell clusters were found in 6, wi
th concomitant corpora amylacea in 1 case and perivascular macrophages
with pigment a sole finding in another case. CONCLUSION: Of the six f
eatures found in cases of mesial temporal sclerosis on MR, increased h
ippocampal signal intensity is the most consistent. A decreased gray-w
hite matter demarcation in the temporal lobe parenchyma is also a freq
uent feature of this disease. A combination of multiple scanning plane
s results in an optimal demonstration of lesions.