Ryan Chandler Daily BS, Presenter: Nothing to Disclose

Michael Flannery BS, Abstract Co-Author: Nothing to Disclose

Philip Varughese BS, Abstract Co-Author: Nothing to Disclose

Keith Thulborn MD, PhD, Abstract Co-Author: Research grant, General Electric Company Owner, Thulborn Associates, Inc

Presurgical planning of patients often requires lateralization of language comprehension and memory. Invasive intra-arterial testing with sodium amobarbital as the patient performs language comprehension and memory tasks achieves this lateralization. Activation maps from fMRI with blood oxygenation level dependent (BOLD) contrast produce comparable lateralization non-invasively. fMRI localizes hippocampal activation with both language comprehension and memory paradigms. This study investigated if there was any differences in hippocampal lateralization between the language comprehension and memory paradigms.

This retrospective study used fMRI studies (3T, echo-planar imaging, TR=3000ms, TE=30ms, voxel size=3X3X3mm3, 26 slices) with both language comprehension and memory paradigms in 43 patients (15:28, females:males; 36 right-handed, 18 epilepsy, 25 other diagnoses). Activation maps were analyzed using voxel-wise, unpaired t-tests at a specified p < 0.05 at different t-thresholds (NIVANA software, www.mrixtechnologies.com). Laterality ratios (LR) and voxel counts (VC) were determined at these multiple statistical thresholds for both paradigms in the hippocampal structures and in each half of each patient's brain. These LR and VC measures for the hippocampus and brain of each patient were compared statistically using a paired t-test.

Trends were independent of statistical thresholds. No significant differences (p>0.23) in volumes of activation or laterality ratios for language and memory were identified for the hippocampus. A significant difference (p<0.000033) was found in the laterality ratio of the two paradigms for the whole brain with the expected left dominance for language comprehension and symmetry for memory.

As the language and memory paradigms provide the same lateralization of hippocampal function during fMRI, only a single paradigm is required to efficiently map both language comprehension and memory.

Language comprehension and memory can be mapped in the hippocampus with fMRI using the single language comprehension paradigm, thereby shortening the examination time and improving patient throughput

Daily, R, Flannery, M, Varughese, P, Thulborn, K, A Comparison of Hippocampal Activation for Language Comprehension and Memory Paradigms in fMRI.  Radiological Society of North America 2006 Scientific Assembly and Annual Meeting, November 26 - December 1, 2006 ,Chicago IL. http://archive.rsna.org/2006/4438963.html