Kyung K Peck PhD, Presenter: Nothing to Disclose

Andrei Holodny, Abstract Co-Author: Nothing to Disclose

Bob Hou PhD, Abstract Co-Author: Nothing to Disclose

Nicole Petrovich, Abstract Co-Author: Nothing to Disclose

Dmitry Bogomolny, Abstract Co-Author: Nothing to Disclose

Philip Gutin, Abstract Co-Author: Nothing to Disclose

To measure the volume of activation (VoA) and time to peak (TTP) of the BOLD fMRI hemodynamic response function (HRF) in the primary motor cortex (PMC) and supplementary motor area (SMA) in brain tumor patients. We hypothesize that as a glioma invades the PMC (but not the SMA), cortical reorganization will occur with the SMA taking over some PMC function: characterized by 1)an increased VoA in the SMA ipsilateral to the tumor and 2)a change in the HRF of the SMA to more closely resemble the PMC.

15 brain tumors (5 GBMs, 5 other gliomas, 1 meningioma, 4 metastases) and 8 controls were studied. Patients were classified as: A)gliomas involving the PMC but not the SMA, B)gliomas in the frontal lobe not involving either PMC or SMA C)metastases and meningiomas involving the PMC. Block paradigm (TR 4000 msec; active/rest=20sec/40sec) using bilateral finger tapping was used to measure the VoA in the SMA and PMC analyzed by AFNI. Event-related paradigms of right or left hand finger tapping (TR 1000 msec; active/rest=4 sec/20sec) were performed using deconvolution analysis to generate the HRF in the SMA and PMC. The TTP of the PMC minus the TTP of the SMA was defined as TTP(P-A).

For group A, the VoA of the tumor side (TS) SMA was significantly greater than the non-tumor side (NTS) in only 2/7 patients. There was no significant difference between the TS and the NTS in group B, C or the controls. TTP(P-A) in controls was 1.0±0.3sec and 1.1±0.2sec in the right and left hemisphere. This was not significantly different from group B (1.2±0.2sec and 0.9±0.5sec in TS and NTS) or group C (0.9±0.4sec and 0.6±0.3sec in TS and NTS). For group A, TTP(P-A) was significantly different on the TS (0.2±0.2sec p<0.002) but not on the NTS (1.1±0.5sec). The TTP of the SMA on the TS in Group A was not statistically different from the TTP of the PMC in the controls, group B or C.

As a glioma invades the PMC, the HRF of the SMA on the TS takes on the appearance of the PMC. This result supports the concept that the SMA may be taking over the primary motor function. HRF analysis may be more sensitive than VoA measurements in detecting earlier brain plasticity.

Peck, K, Holodny, A, Hou, B, Petrovich, N, Bogomolny, D, Gutin, P, Brain Plasticity Due to Tumor Growth Demonstrated by Change in the BOLD fMRI Hemodynamic Response Function of the Supplementary Motor Area (SMA).  Radiological Society of North America 2005 Scientific Assembly and Annual Meeting, November 27 - December 2, 2005 ,Chicago IL. http://archive.rsna.org/2005/4407150.html