2001 ASNR Annual Meeting Abstracts
Focal Lesion in the Splenium of the Corpus Callosum
on FLAIR MR Imaging: A Common Finding after Brain
Pekala, J. S. * Mamourian, A. C.
Dartmouth Hitchcock Medical Center, Lebanon, NH
It is unusual to encounter a nonhemorrhagic focal lesion within the splenium of the corpus
callosum (1). We identified focal lesions within the splenium of the corpus callosum on FLAIR
MR imaging on follow-up of scans of several patients with brain neoplasms. We undertook an
investigation to determine the frequency of this finding in this patient group.
Materials & Methods
We examined the FLAIR images of 18 patients with a history of prior brain radiation therapy for
primary brain neoplasms. The scans were evaluated for the callosal lesions and white matter
disease which was graded on a scale of 0 (none) to 3(severe). The mean age of the study
population was 44.1 years, and all had received a brain radiation dose of between 5400–
6000cGY. The postradiation MR exams were performed an average of approximately 6 months
following completion of therapy. A subsecond group of 10 patients was selected in whom both
pre and postradiation therapy FLAIR imaging were available.
High signal within the splenium of the corpus callosum was evident on 16 of the 18 (89%)
postradiation axial FLAIR exams. Seventeen of the 18 were graded with none or mild white
matter disease. In patients with both pre and posttherapy FLAIR images, seven out of 10 patients
developed the abnormal signal in the splenium of the corpus callosum following radiation
High signal on FLAIR imaging with the splenium of the corpus callosum is a common finding
following brain radiation therapy and can be seen in the absence of other white matter changes
from radiation injury. While the clinical significance remains uncertain, it is important for the
radiologist to recognize this finding and not mistake it for tumor spread.
1. Kim, Sam Soo, et al. Focal lesion in the splenium of the corpus callosum in epileptic
patients: anti-epileptic drug toxicity?AJNR Am J Neuroradiol 1999;20:125–129