Hyperintense dentate nucleus on unenhanced T1-weighted MR images is associated with a history of brain irradiation.
OBJECTIVE
To assess the frequency of hyperintensity in the dentate nucleus on T1-weighted magnetic resonance (MR) images and to establish correlations between such hyperintensity and clinical factors, including a history of brain irradiation.


METHODS
This study was approved by the institutional review board, and each patient provided written informed consent. Three hundred sixty-two patients (164 men, 198 women; mean age, 62 years) were evaluated. Unenhanced T1-weighted MR images were obtained by using a spin-echo sequence at 3.0 T. Two neuroradiologists, who were blinded to clinical data, independently evaluated the signal intensity of the dentate nucleus compared with the signal intensity of the central white matter of the cerebellum by using a four-point graded response scale (grade 4 indicated prominent hyperintensity; grade 3, faint hyperintensity; grade 2, isointensity; and grade 1, hypointensity). Backward stepwise regression analysis was used to evaluate the relationship between signal intensity grades and the following clinical factors: sex, age, the interaction between age and sex, hypertension, dyslipidemia, diabetes mellitus, liver dysfunction, brain infarction, brain tumor, spinocerebellar degeneration, multiple sclerosis, a history of chemotherapy, and a history of brain irradiation.


RESULTS
T1-hyperintense dentate nuclei were present in 41 (11%) of the 362 patients. Of these 41 patients, 31 (76%) had a history of brain irradiation. Signal intensity grade of the dentate nucleus on T1-weighted MR images correlated significantly with a history of brain irradiation (P < .001) but no other clinical factor.


CONCLUSIONS
A hyperintense dentate nucleus may be seen on unenhanced T1-weighted MR images in some patients and may be associated with a history of brain irradiation.
Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan.
Seiko
S
Kasahara
Yukio
Y
Miki
Mitsunori
M
Kanagaki
Akira
A
Yamamoto
Nobuyuki
N
Mori
Takeshi
T
Sawada
Toshiaki
T
Taoka
Tomohisa
T
Okada
Kaori
K
Togashi
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016543:Central Nervous System Neoplasms / Q000532:radiotherapy*; D002529:Cerebellar Nuclei / Q000528:radiation effects*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D012189:Retrospective Studies