Jagadeesh Singh MD, FRCR, Presenter: Nothing to Disclose

Neelan Pillay MD, FRCPC, Abstract Co-Author: Nothing to Disclose

S Wiebe MD, FRCPC, Abstract Co-Author: Nothing to Disclose

Terry Myles MD, FRCPC, Abstract Co-Author: Nothing to Disclose

James Scott MD, FRCPC, Abstract Co-Author: Nothing to Disclose

Abnormal amygdala enlargement is occasionally identified in patients investigated for temporal lobe epilepsy (TLE), but the underlying etiology is not well understood. We sought to further characterize this imaging abnormality and determine any underlying etiology and outcome

A series of 27 patients with temporal lobe epilepsy were identified as having abnormal amygdala enlargement without enhancement on MRI. The MR scans were re-reviewed to determine any other relevant abnormalities. Six of the 27 patients also had MR spectroscopy localised to bilateral amygdala.

All 27 patients had abnormal amygdala enlargement that was ipsilateral and corresponded to the epileptogenic focus on scalp EEG. The enlargement involved the right side in 14 patients and left amygdala in 13 and none bilateral. All enlarged amygdala had increased T2/FLAIR signal, without enhancement. Five out of the six patients who had MR spectroscopy revealed increased myoinositol within the enlarged amygdala, compared to the contralateral side. In 7 cases, there was combined amygdala and hippocampal enlargement with signal abnormality. Eight patients underwent surgical resection and pathology revealed gliosis in 1, cortical dysplasia in 1, hippocampal sclerosis in 2, and was normal in 4 patients. Of the remaining 19 out of 27 patients, the imaging findings were stable in 11 and resolved in 8 patients.

Abnormal amygdala enlargement may be identified as an isolated finding in patients investigated for temporal lobe epilepsy. Although not well understood, such findings are important to search for as they can be subtle and, on occasion, appear reversible on follow-up imaging. MR spectroscopy may be helpful and demonstrate elevated myoinositol within the enlarged amygdala. Further imaging and pathologic correlational studies may be required to clarify the underlying etiology

MR spectroscopy may be helpful and demonstrate elevated myoinositol within the enlarged amygdala and may be used in the evaluation of amygdala abnormality in temporal lobe epilepsy

Singh, J, Pillay, N, Wiebe, S, Myles, T, Scott, J, Isolated Abnormal Amygdala Enlargement in Temporal Lobe Epilepsy.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9012982.html