Decreases of Blood Oxygenation Level—Dependent Signal in the Activated Motor Cortex during Functional Recovery after Resection of a Glioma
Yoshihiro Murataa,
Kaoru Sakatania,b,
Yoichi Katayamaa,
Norio Fujiwaraa,
Tatsuya Hoshinoa,
Chikashi Fukayaa,c and
Takamitsu Yamamotoa,c
a Department of Neurosurgery, Nihon University School of Medicine, Tokyo, Japan
b Divisions of Optical Brain Engineering, Nihon University School of Medicine, Tokyo, Japan
c Applied System Neuroscience, Nihon University School of Medicine, Tokyo, Japan
View larger version (88K):
[in a new window]
|
FIG 1. Preoperative gadolinium-enhanced T1- and T2-weighted MR images (top), showing a left frontal low-grade glioma. Postoperative gadolinium-enhanced T1- and T2- weighted MR images (bottom), showing subtotal removal of the glioma.
| |
View larger version (50K):
[in a new window]
|
FIG 2. Changes in fMR findings before and after tumor resection.
A, Activation maps of BOLD fMRI for the right grasping task (lesion side) and the left grasping task (nonlesion side) before and after tumor resection. Postoperative fMR image 2 days after surgery demonstrated negative BOLD signal changes in the motor cortex on the lesion side. Extended activation in the ipsilateral secondary motor cortex was also observed after surgery. On the postoperative fMR image 22 days after surgery, the negative BOLD signal intensity areas in the motor cortex on the lesion side were decreased in association with an increase in activation areas. By contrast, left-hand grasping activated the motor cortex on the nonlesion side consistently before and after surgery. White arrows indicate the region of interest (a and c, positive signal-intensity changes; b, negative signal-intensity changes).
B, Time course of the BOLD signal changes during the task (blue background).
| |
View larger version (14K):
[in a new window]
|
FIG 3. NIRS measurements of evoked CBO changes in the motor cortex on the lesion side before and after tumor resection. The ordinate indicates the concentration changes of the NIRS parameters in arbitrary units. The horizontal thick bar denotes the task period (40 seconds). Preoperative NIRS demonstrated a decrease of deoxy-Hb associated with increases of oxy-Hb and total-Hb (left), which is consistent with the physiological basis of BOLD contrast. Postoperative NIRS (2 days and 22 days after surgery) demonstrated similar increases of oxy-Hb and total-Hb, indicating the occurrence of rCBF increases in response to neuronal activation (center and right). Two days after surgery, however, deoxy-Hb increased from the baseline during the entire course of the task, whereas deoxy-Hb did not change significantly 22 days after surgery. These alterations in deoxy-Hb correlated with the changes in size of the negative BOLD signal areas in the motor cortex on the lesion side (Fig 2A).
| |
