Hyperintense Dentate Nuclei on T1-Weighted MRI: Relation to Repeat Gadolinium Administration

Fellows’ Journal Club

Editor’s Comments

This is a retrospective review of the medical records of 706 consecutive patients who were treated with irradiation for primary brain tumors at The Johns Hopkins Medical Institutions between June 1995–January 2010. The authors found that the appearance of hyperintense dentate nuclei (HDN) is likely permanent, given the long follow-up time of the study, and a significant association between HDN and repeated contrast-enhanced MR studies. A significant increase in the likelihood of HDN occurred after 4 or more enhanced scans, and total dose of 77 ml of gadolinium contrast agent. They found no association between radiation exposure and HDN.

Abstract

HDN on axial T1WI of a subject who underwent 25 CEMRI scans and 5400-cGy RT for pilocytic astrocytoma originating from the optic nerve. DN was unremarkable on the CT scan (not shown here) of this particular case. Initial HDN (A) becomes more obvious on follow-up studies performed 5 (B) and 8 (C) years after the first study with positive findings. Images A and B were obtained from 1.5T and C was obtain from 3T scanners. This individual underwent 12 CEMRIs during the follow-up.
HDN on axial T1WI of a subject who underwent 25 CEMRI scans and 5400-cGy RT for pilocytic astrocytoma originating from the optic nerve. DN was unremarkable on the CT scan (not shown here) of this particular case. Initial HDN (A) becomes more obvious on follow-up studies performed 5 (B) and 8 (C) years after the first study with positive findings. Images A and B were obtained from 1.5T and C was obtain from 3T scanners. This individual underwent 12 CEMRIs during the follow-up.

BACKGROUND AND PURPOSE

A hyperintense appearance of the dentate nucleus on T1-weighted MR images has been related to various clinical conditions, but the etiology remains indeterminate. We aimed to investigate the possible associations between a hyperintense appearance of the dentate nucleus on T1-weighted MR images in patients exposed to radiation and factors including, but not limited to, the cumulative number of contrast-enhanced MR images, amount of gadolinium administration, dosage of ionizing radiation, and patient demographics.

MATERIALS AND METHODS

The medical records of 706 consecutive patients who were treated with brain irradiation at The Johns Hopkins Medical Institutions between 1995 and 2010 were blindly reviewed by 2 readers.

RESULTS

One hundred eighty-four subjects were included for dentate nuclei analysis. Among the 184 subjects who cumulatively underwent 2677 MR imaging studies following intravenous gadolinium administration, 103 patients had hyperintense dentate nuclei on precontrast T1-weighted MR images. The average number of gadolinium-enhanced MR imaging studies performed in the group with normal dentate nuclei was significantly lower than that of the group with hyperintense dentate nuclei. The average follow-up time was 62.5 months. No significant difference was observed between hyperintense and normal dentate nuclei groups in terms of exposed radiation dose, serum creatinine and calcium/phosphate levels, patient demographics, history of chemotherapy, and strength of the scanner. No dentate nuclei abnormalities were found on the corresponding CT scans of patients with hyperintense dentate nuclei (n = 44). No dentate nuclei abnormalities were found in 53 healthy volunteers.

CONCLUSIONS

Repeat performance of gadolinium-enhanced studies likely contributes to a long-standing hyperintense appearance of dentate nuclei on precontrast T1-weighted-MR images.

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Hyperintense Dentate Nuclei on T1-Weighted MRI: Relation to Repeat Gadolinium Administration
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jross
Jeffrey Ross • Mayo Clinic, Phoenix

Dr. Jeffrey S. Ross is a Professor of Radiology at the Mayo Clinic College of Medicine, and practices neuroradiology at the Mayo Clinic in Phoenix, Arizona. His publications include over 100 peer-reviewed articles, nearly 60 non-refereed articles, 33 book chapters, and 10 books. He was an AJNR Senior Editor from 2006-2015, is a member of the editorial board for 3 other journals, and a manuscript reviewer for 10 journals. He became Editor-in-Chief of the AJNR in July 2015. He received the Gold Medal Award from the ASSR in 2013.