Comparison of Hypothesis- and a Novel Hybrid Data/Hypothesis-Driven Method of Functional MR Imaging Analysis in Patients with Brain Gliomas

Results of the ICA decomposition on a patient with a brain tumor. A, Time courses of the first 4 ranked ICs. B, Comparison between the results of power spectrum ranking and temporal correlation on all the separated ICs. C, Spatial maps of the first 4 ranked ICs, thresholded at z > 2.

GLM (left column) and ICA-GLM (right column) activations (P < .001, uncorrected) during VGt in representative controls and patients. The left hemispheres are displayed with different Talairach x-values, to visualize the IFG (Broca area) and TPJ (Wernicke area). The bar charts in the lower left-hand corners show the correlation coefficients of the first 4 ICs and the task predictor; the chosen IC is displayed in red. In controls, both the GLM and ICA-GLM show activation in the IFG and TPJ. In patient 1 (left parietal glioma), the ICA-GLM activates both the IFG and TPJ, whereas the GLM activates only the IFG. In patient 2 (left temporal glioma), the ICA-GLM activates both the IFG and TPJ, whereas no language regions are detected with the GLM. In patient 3 (left temporal glioma), the ICA-GLM activates only the IFG, whereas no language regions are detected with the GLM.

Comparison of LI values obtained with the classic GLM and ICA-GLM of controls and patients for the following tasks: With WGt, 2 controls presented a bilateral LI (−0.2 < LI < 0.2) with the GLM. The same 2 subjects showed a left dominance with ICA-GLM, while the third showed a bilateral organization with ICA-GLM. With VGt, the same 2 controls with bilateral LI with GLM. Both presented a left dominance with ICA-GLM. With WGt, 20 patients had an LI indicating a bilateral language organization with the GLM: Seven presented left dominance with ICA-GLM and 13 remained bilateral. Three patients showed a left dominance with the GLM but a bilateral dominance with ICA-GLM. Eighteen of the remaining patients had a left dominance with both the GLM and ICA-GLM, and 1, a concordant right dominance. With VGt, 16 patients presented a bilateral LI indicated by the GLM, of which 6 had left and 1 right dominance with ICA-GLM. Four patients showed a left dominance with the GLM but a bilateral dominance with ICA-GLM. One patient presented a right dominance with the GLM but a bilateral dominance with ICA-GLM. Of the remaining patients, 20 had a left dominance with both the GLM and ICA-GLM and 1 patient had a concordant right dominance.