Clinical Applications Of Magnetoencephalography Research Articles

脳磁図の臨床応用に関する文献レビュー (第6報) : 神経変性・脱髄疾患と神経リハビリテーション

脳磁図の臨床応用に関する文献レビュー (第6報) : 神経変性・脱髄疾患と神経リハビリテーション

脳磁図の臨床応用に関する文献レビュー (第4報) : 精神科疾患・認知症

脳磁図の臨床応用に関する文献レビュー (第4報) : 精神科疾患・認知症

脳磁図の臨床応用に関する文献レビュー (第5報) : 脳腫瘍

脳磁図の臨床応用に関する文献レビュー (第5報) : 脳腫瘍

脳磁図の臨床応用に関する文献レビュー(第3報) : 小児疾患

脳磁図の臨床応用に関する文献レビュー(第3報) : 小児疾患

脳磁図の臨床応用に関する文献レビュー (第1報): てんかん

脳磁図の臨床応用に関する文献レビュー (第1報): てんかん

Questionnaire survey of current status and problems in clinical applications of magnetoencephalography (MEG) in Japan

Questionnaire survey of current status and problems in clinical applications of magnetoencephalography (MEG) in Japan

Clinical applications of magnetoencephalography in epilepsy

Magnetoencehalography (MEG) is being used with increased frequency in the pre-surgical evaluation of patients with epilepsy. One of the major advantages of this technique over the EEG is the lack of distortion of MEG signals by the skull and intervening soft tissue. In addition, the MEG preferentially records activity from tangential sources thus recording activity predominantly from sulci, which is not contaminated by activity from apical gyral (radial) sources. While the MEG is probably more sensitive than the EEG in detecting interictal spikes, especially in the some locations such as the superficial frontal cortex and the lateral temporal neocortex, both techniques are usually complementary to each other. The diagnostic accuracy of MEG source localization is usually better as compared to scalp EEG localization. Functional localization of eloquent cortex is another major application of the MEG. The combination of high spatial and temporal resolution of this technique makes it an extremely helpful tool for accurate localization of visual, somatosensory and auditory cortices as well as complex cognitive functions like language. Potential future applications include lateralization of memory function.

Clinical applications of magnetoencephalography.

Magnetoencephalography (MEG), in which magnetic fields generated by brain activity are recorded outside of the head, is now in routine clinical practice throughout the world. MEG has become a recognized and vital part of the presurgical evaluation of patients with epilepsy and patients with brain tumors. We review investigations that show an improvement in the postsurgical outcomes of patients with epilepsy by localizing epileptic discharges. We also describe the most common clinical MEG applications that affect the management of patients, and discuss some applications that are close to having a clinical impact on patients.

SY2.1 Neurophysiologic Basis and Clinical Application of Magnetoencephalography

SY2.1 Neurophysiologic Basis and Clinical Application of Magnetoencephalography

Clinical application of magnetoencephalography

Magnetoencephalography (MEG) has the potential to quantitatively detect the magnitude of neuronal activity. Using the single equivalent current dipole/sphere head model for the inverse problem solution, we chose N20m of a somatosensory-evoked field (SEF) as a candidate to prove its usefulness. To avoid fluctuation in response due to the variation of stimulus intensity, we set the stimulus intensity at more than 1.5 times the threshold of the thenar muscle twitch (TMT). To verify the accuracy of our measurement system, we studied the measurement reproducibility. The mean and standard deviation (S.D.) were both about 1.8 nAm. Therefore, changes of more than 5.4 nAm (mean+2S.D.) were statistically significant. To prove the consistency through another functional evaluation, we compared the results of the dipole moment measurement with the results of the cerebral blood flow (CBF) measurement. The group with the CBF hemisphere laterality displayed a large moment difference between the hemispheres compared to the group without laterality. A representative case showed subclinical function impairment that was able to be detected by the moment measurement. Dipole moment was thus confirmed to be a reliable quantitative index of cortical response to the somatosensory stimulus, and the dipole moment of MEG holds the promise as a clinical tool for the direct quantification of neuronal activity.

Clinical Application of Magnetoencephalography : from Functional Brain Mapping to Pathophysiological Imaging(Special Issue : Research of Biomagnetism)

Clinical Application of Magnetoencephalography : from Functional Brain Mapping to Pathophysiological Imaging(Special Issue : Research of Biomagnetism)

Clinical application of magnetoencephalography in a patient with corticobasal degeneration.

Previous neuroimaging studies in corticobasal degeneration (CBD), such as MRI and positron emission tomography, showed lateralized cortical atrophy and a decrease in cortical oxygen metabolism, respectively. The advantage of magnetoencephalography in the research of the auditory system is that activity of both hemispheres can be detected separately. Auditory-evoked magnetic fields (AEFs) were then applied to a patient with corticobasal degeneration. The strength of N100m equivalent current dipoles (ECD) in left hemisphere was extremely smaller (20 nAm) than that in right hemisphere (48 nAm). This results implies that CBD patient might have a decrease in the number of neurons in the primary auditory cortex. This study suggests that AEF measurement is one of the most powerful tools for detecting latent impairment of auditory function in patients with corticobasal degeneration.

Clinical application of magnetoencephalography by multichannel SQUID systems

Clinical application of magnetoencephalography by multichannel SQUID systems

小児神経疾患における脳磁図(MEG)の臨床応用

小児神経疾患における脳磁図(MEG)の臨床応用