Heavily T2-weighted MR imaging of white matter tracts in the hypothalamus: normal and pathologic demonstrations.
OBJECTIVE
The MR appearance of white matter tracts in the hypothalamus and the role of the hypothalamus as a memory mechanism have not been sufficiently described in clinical settings. Heavily T2-weighted black-and-white reversed (T2R) images were assessed to reveal their visualization and clinical significance.


METHODS
One hundred healthy subjects and three patients with hypothalamic lesions underwent fast spin-echo MR imaging to reveal the postcommissural fornix (PF) and mammillothalamic tract (MT).


RESULTS
The PF was identifiable in axial and/or coronal sections in all healthy subjects. No remarkable asymmetry of its size or course was evident. Both anteroposterior and vertical dimensions ranged from 10.5 to 14 mm. The MT was visible in one or two axial sections above the mammillary body in 64% of healthy subjects and in a coronal section in 36%. Two patients with glioblastoma multiforme and lacunar infarct at the hypothalamus presented with anterograde amnesia; T2R imaging revealed involvement of both the PF and MT. The third patient had a suprasellar craniopharyngioma with PF injury sparing the MT resulting from surgical manipulation and was free of memory deficit. Anterograde amnesia was evident only when both the PF and MT were injured.


CONCLUSIONS
T2R images have made a high rate of detection of the PF and MT possible and could provide a more detailed correlation of hypothalamic neuroanatomy and memory mechanism in clinical settings.
Saeki
N
N
Department of Neurological Surgery, Chiba University School of Medicine, Japan.
Sunami
K
K
Kubota
M
M
Murai
H
H
Takanashi
J
J
Iuchi
T
T
Yamaura
A
A
D000293:Adolescent; D000328:Adult; D000368:Aged; D002544:Cerebral Infarction / Q000175:diagnosis; D005260:Female; D020712:Fornix, Brain / Q000293:injuries / Q000473:pathology; D005909:Glioblastoma / Q000175:diagnosis; D006801:Humans; D007029:Hypothalamic Neoplasms / Q000175:diagnosis; D007031:Hypothalamus / Q000033:anatomy & histology* / Q000473:pathology*; D007431:Intraoperative Complications / Q000175:diagnosis; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012016:Reference Values