Seizures After Stereotactic Radiosurgery for Benign Supratentorial Meningiomas: An Uncontrollable Type of Seizure?

OBJECTIVE: We investigated seizure outcomes of patients with supratentorial meningiomas (ST-MNGs) treated with stereotactic radiosurgery (SRS). METHODS: One hundred and thirty-three patients with a total of 144 ST-MNGs, who were treated with SRS between 2009 and 2016, were included in this study. The mean age was 59.0 ± 11.9 years (range, 13-87 years). The mean follow-up duration was 49.8 ± 24.5 months (range, 9-96 months). The median tumor volume was 2.60 cm3 (range, 0.06-32.40 cm3), and the median marginal dose was 14.0 Gy (range, 11.0-20.0 Gy). Postradiosurgery peritumoral edema (PRPTE) was developed in 43 lesions (29.9%). RESULTS: New seizure attacks developed in 16 patients (12.0%) after SRS (first seizure attack in 14 [87.5%]; seizure aggravation in 2 [12.5%]). In 15 patients with new seizure attacks (93.8%), PRPTE was proved on magnetic resonance imaging. The mean interval between SRS and new seizure attack was 6.6 ± 7.1 (range, 0.23-28.8) months. Simple partial seizure was the most common type of seizure (n = 9 [56.3%]). Five patients (31.3%) were seizure-free with antiepileptic drug (AED) medication (3 [18.8%] withdrew AEDs during the follow-up period); however, the remaining 11 patients (68.7%) did not achieve seizure-free outcomes even with AED medication. Moreover, seizures became intractable in 8 patients (50.0%). From multivariate analysis, the significant predictors of post-SRS seizure attack were PRPTE (odds ratio, 53.99; 95% confidence interval, 5.214-559.1; P = 0.001) and brain-tumor contact-surface index (odds ratio, 2.466; 95% confidence interval, 1.183-5.138; P = 0.016). CONCLUSIONS: The clinical outcomes of seizures after SRS for ST-MNGs fall short of our expectation, and seizures seem to be uncontrollable and even intractable.

Target-specific rCBF changes induced by 0.3-T static magnetic field exposure on the brain.

The magnetic field has been regarded as both harmful and beneficial for its applications on human brains including transcranial magnetic stimulation (TMS), but its effects still remain in question. Here, we determined using single photon emission computed tomography (SPECT) if 0.3-T static magnetic field could alter regional cerebral blood flow (rCBF) in target and other brain regions in healthy subjects. The permanent static magnet (0.3 T, unipolar, disk shaped, 4 cm diameter and 1 cm thick) was placed on the right frontotemporal region of the brain for each of 14 healthy subjects. Tc-99m ECD perfusion SPECT was taken to compare the CBF patterns in the subjects exposed to the static magnet field with those of the resting and sham conditions. We found that the rCBF was significantly increased in the right frontal and parietal regions and the right insula. On the other hand, rCBF was rather decreased in the left frontal and left parietal regions (P<0.05). These results of this basic study suggest that 0.3-T static magnetic field induces an increase in rCBF in the targeted brain areas non-invasively, which may result from a decrease in rCBF in contralateral regions.

Verbal working memory dysfunction in schizophrenia: an FMRI investigation.

Impaired processing of working memory information is one of the cognitive deficits seen in patients with schizophrenia. This study aims at corroborating the differences in the brain activities involved in the process of working memory between patients with schizophrenia and the controls. Twelve patients with schizophrenia and 11 controls participated in the study. Functional magnetic resonance imaging (fMRI) was used to assess cortical activities during the performance of a two-back verbal working memory paradigm using the Korean alphabet as mnemonic content. Group analysis revealed that inferior fontal, middle frontal, and superior temporal region showed decreased cortical activities in the patient group compared to those of the controls. This study showed a decreased activation in inferior fontal (BA 47), middle frontal (BA 6), and superior temporal (BA 22/38) neural networks from the patient group and confirmed the earlier findings on the impaired working memory of schizophrenic patients in the fMRI investigation.

Altered verbal working memory process in patients with Alzheimer's disease: an fMRI investigation.

Impaired working memory processing is one of the broad range of cognitive deficits in patients with Alzheimer's disease (AD). We aimed to elucidate the differences in brain activities involved in the process of working memory between AD patients and healthy comparison subjects. Twelve patients with AD were recruited along with 12 healthy volunteers as a comparison group. Functional magnetic resonance imaging was employed to assess cortical activities during the performance of a 1-back working memory paradigm using the Korean alphabet as mnemonic content. Subsequently, the difference in neural activities between the 2 groups was analyzed. The AD group performed the tasks with reduced accuracy. Group comparison analysis revealed that the AD group showed decreased brain activity in the left frontal pole (Brodmann area, BA, 10), the left ventrolateral prefrontal cortex (BA47), the left insula (BA13) and the right premotor cortex (BA6) compared to the control group. The AD group showed increased activation in the left precuneus (BA7) compared to the control group. A decreased level of activation in the prefrontal cortex and an increased level of activation in the parietal neural networks from the patient group may document an altered verbal working memory process in the patients with AD.

Quantification analysis of 123I-IPT single photon emission computed tomography uptake in the striatum of parkinsonism with the standard magnetic resonance template.

This study evaluated the striatal specific binding ratio (SBR), the anterior to posterior ratio of the striatum (APR) and its reproducibility by employing a template-based registration (TBR) method using the coregistered to the standard T1 magnetic resonance (MR) template (SMRT) as a replacement for the MR image of each patient. The 123I-IPT single photon emission computed tomography (SPECT) images of 30 patients with Idiopathic Parkinson's disease (IPD) and 11 normal controls were analyzed. The region of interest (ROI) was positioned manually in the same slice showing the highest striatal activity using the manual ROI method, while the ROI were positioned automatically in the mid striatal slice of the SPECT image coregistered to the SMRT. The SBR obtained using the TBR method showed a strong correlation with those using the manual method in all groups: normal controls (r = 0.851, P = 0.001), early IPD (r = 0.841, P < 0.001), and severe IPD (r = 0.702, P = 0.007). The APR obtained by the TBR correlated with those using the manual method in only the early IPD (r = 0.72, P = 0.001), while those obtained using the manual method showed no correlation in the three groups (P > 0.05). The reproducibility (rmsCV) of the TBR method was 7.2% (normal controls, 5.2%; mild IPD, 4.2%; severe IPD, 10.8%), while the reproducibility of the manual method was 31% (normal controls, 19.7%; mild IPD, 21.7%; severe IPD, 46.2%). This shows that the use of 123I-IPT SPECT for assessing IPD is affected by the method used to position the striatal ROI. This study showed that the TBR method using the SMRT is useful in diagnosing the IPD and assessing the disease severity with a high reproducibility, indicating a possibility of using the TBR method as a good replacement for the manual method.

Head motion analysis during cognitive fMRI examination: application in patients with schizophrenia.

OBJECTIVES: Functional MRI (fMRI) has become an important imaging modality for analyzing the neural mechanisms underlying schizophrenia. Earlier studies indicate that patients with schizophrenia tend to generate involuntary and unnecessary head motion during visual tasks. Since head motion can deteriorate the quality of fMRI data, an investigation was needed to examine the type and extent of head motion from patients with schizophrenia undergoing fMRI. METHODS: Patients with schizophrenia and demographically-matched healthy comparison subjects underwent fMRI examination involving visual working memory tasks. We obtained head movement parameters (three translational and three rotational) through mathematical realignment of the volumetric image data, and transformed these parameters into head displacement indices to quantify the subject's head motion in space. RESULTS: We found no group difference in displacement indices between the two groups. Group comparison of movement parameters indicated that the patient group showed reduced head motion along the superior-inferior direction when compared to healthy individuals. CONCLUSION: These results suggest that cognitive fMRI examination in patients with schizophrenia can be successfully conducted without the deteriorative effects of head motion.

Voxel based comparison of glucose metabolism in the differential diagnosis of the multiple system atrophy using statistical parametric mapping.

OBJECTIVE: A differential diagnosis of idiopathic parkinsonian disease (IPD) and multiple system atrophy (MSA) is difficult due to their common signs and symptoms. The aim of this 18F-2-fluoro-2 deoxyglucose (18F-FDG) positron emission tomography (PET) study was to compare the regional cerebral glucose metabolism in MSA with that in IPD by statistical parametric mapping (SPM) and image registration. METHODS: The 18F-FDG PET images of MSA and IPD patients were assessed by SPM and image registration to determine metabolic patterns that may be useful in differentiating between the two groups. Eleven patients with MSA, eight patients with IPD and 22 healthy controls participated in the study. RESULTS: The IPD patients were found to have a significant glucose hypometabolism in comparison with the healthy controls in the prefrontal, lateral frontal, and parietotemporal cortices, and the cingulate and caudate areas (p< or =0.01, 100 voxel-level). In patients with MSA, hypometabolism was observed in the putamen, pons, and cerebellum in comparison with the healthy controls and IPD patients. CONCLUSION: The voxel-based analysis of 18F-FDG PET images showed detailed differences between IPD and MSA, which may be useful in differentiating the two disease entities, as evidenced by the correlation of glucose metabolism with disease severity and dopamine agonist medication. The mapping analysis of 18F-FDG PET images might be a useful adjunctive method of a differential diagnosis for parkinsonism in a clinical setting.

Cerebral glucose metabolism in corticobasal degeneration comparison with progressive supranuclear palsy using statistical mapping analysis.

This study measured the cerebral glucose metabolism in patients suffering from corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP). The aim was to determine if there is a different metabolic pattern using (18)F-labeled 2-deoxyglucose ((18)F-FDG) positron emission tomography (PET). The regional cerebral glucose metabolism was examined in 8 patients diagnosed clinically with CBD (mean age 69.6 +/- 7.8 years; male/female: 5/3), 8 patients with probable PSP (mean age 67.8 +/- 4.5 years; male/female: 4/4) and 22 healthy controls. The regional cerebral glucose metabolism between the three groups was compared using statistical parametric mapping (SPM) with a voxel-by-voxel approach (p < 0.001, 200-voxel level). Compared with the normal controls, asymmetry in the regional glucose metabolism was observed in the parietal, frontal and cingulate in the CBD patients. In the PSP patients, the glucose metabolism was lower in the orbitofrontal, middle frontal, cingulate, thalamus and mid-brain than their age matched normal controls. A comparison of the two patient groups demonstrated relative hypometabolism in the thalamus, the mid-brain in the PSP patients and the parietal lobe in CBD patients. These results suggest that when making a differential diagnosis of CBD and PSP, voxel-based analysis of the (18)F-FDG PET images using a SPM might be a useful tool in clinical examinations.

Working memory processing of facial images in schizophrenia: fMRI investigation.

Impaired processing of facial information is one of the broad ranges of cognitive deficits seen in patients with schizophrenia. This study aimed to elucidate the differences in brain activities involved in the process of facial working memory (images of neutral faces as mnemonic content) between schizophrenic patients and healthy comparison subjects using functional magnetic resonance imaging (fMRI). Group comparison analysis revealed aberrant activities from the patient group in several cortical areas, including the left fusiform gyrus, right superior frontal gyrus, bilateral middle frontal gyri/insula, and left middle temporal gyrus. A decreased level of activity in the left fusiform gyrus, along with performance reduction, implicates abnormal processing of facial information in schizophrenia.

Different metabolic patterns analysis of Parkinsonism on the 18F-FDG PET.

Idiopathic Parkinson's disease (IPD), progressive supranuclear palsy (PSP) and multiple system atrophy (MSA) are the most common movement disorders associated with neurodegenerative disease. A clinical differential diagnosis of IPD and atypical Parkinsonian disorders, such as MSA and PSP, is often complicated by the presence of symptoms common to both groups. Since Parkinsonism has a different pathophysiology in the cortical and subcortical brain structures, assessing the regional cerebral glucose metabolism may assist in making a differential diagnosis of Parkinsonism. The 18F-FDG PET images of IPD, MSA and PSP were assessed using statistical parametric mapping (SPM) in order to determine the useful metabolic patterns. Twenty-four patients with Parkinsonism: eight patients (mean age 67.9 +/- 10.7 years; M/F: 3/5) with IPD, nine patients (57.9 +/- 9.2 years; M/F: 4/5) with MSA and seven patients (67.6 +/- 4.8 years; M/F: 3/4) with PSP were enrolled in this study. All patients with Parkinsonism and 22 age-matched normal controls underwent 18F-FDG PET, (after 370 MBq 18F-FDG). The three groups and the individual IPD, MSA and PSP patients were compared with a normal control group using a two-sided t-test of SPM (uncorrected P < 0.01, extent threshold > 100 voxel). The IPD, MSA and PSP groups showed significant hypometabolism in the cerebral neocortex compared to the normal control group. The MSA group showed significant hypometabolism in the putamen, pons and cerebellum compared to the normal controls and IPD groups. In addition, PSP showed significant hypometabolism in the caudate nucleus, the thalamus, midbrain and the cingulate gyrus compared to the normal controls, the IPD and the MSA groups. In conclusion, an assessment of the 18F-FDG PET images using SPM may be a useful adjunct to a clinical examination when making a differential diagnosis of Parkinsonism.