Metabolic profiling of atypical meningioma and recurrent meningioma: a comparative analysis with proton magnetic resonance spectroscopy.

OBJECTIVE: Meningiomas are predominantly benign, but some cases exhibit recurrent growth after surgery and undergo malignant transformation to WHO grade 2 or grade 3. Despite progress in genetic analyses, advancements in metabolomic analysis remain less established. Herein, the authors investigated metabolic activity differences between WHO grade 1 meningiomas and WHO grade 2 or 3 meningiomas by noninvasively using proton magnetic resonance spectroscopy (1H-MRS), aiming to preoperatively estimate malignancy. They also reviewed the literature to elucidate this aspect of meningioma research. METHODS: At Ryukyu University Hospital, the authors focused on 93 patients diagnosed with meningioma between 2011 and 2021. The inclusion criteria encompassed prior surgery, pathological diagnoses of meningioma, and preoperative 1H-MRS. Group I included 71 patients with WHO grade 1 meningioma and group II included 22 patients, comprising 19 and 3 with WHO grade 2 and 3 meningioma, respectively. The authors retrospectively conducted a comparative analysis of patient backgrounds and tumor metabolites. RESULTS: Group I and II did not differ significantly in terms of patient demographic characteristics (age and sex). Group II demonstrated a significantly lower extent of tumor resection (p < 0.01), higher MIB-1 labeling index (LI) (p < 0.05), higher incidence of prior irradiation (p < 0.001), and increased rate of tumor recurrence (p = 0.005) compared to group I. According to 1H-MRS, all metabolites, except lactate, displayed significantly higher median creatine (Cr) ratios in group II than group I: glutamine/Cr was 8.46, glutamate/Cr was 9.49, lipid/Cr was 11.36, and choline/Cr was 2.77. According to the receiver operating characteristic (ROC) analysis, glutamine had the largest area under the curve of 0.765 among 10 metabolites, and the cutoff value for distinguishing between group I and II was 5.76. CONCLUSIONS: In cases pathologically graded as WHO grade 2 or 3 meningiomas, metabolic products such as glutamine, glutamate, lipids, and choline increased significantly. These changes were correlated with elevation of the MIB-1 LI. In group II, the mean MIB-1 LI was 8.58, significantly higher than in group I, suggesting a strong association with pathological malignancy. Therefore, 1H-MRS may help to noninvasively predict tumor metabolic activity and tumor recurrence. Furthermore, the authors concluded from the ROC analysis that glutamine may be a potential indicator of future growth of meningioma and benefits of early surgery.

The usefulness of indocyanine green during surgery for hypervascular posterior fossa tumors.

BACKGROUND: Cerebral hemangioblastomas are benign tumors with abundant blood flow that occur mainly in the posterior fossa. Tumor removal en bloc is important in surgical treatment because of the risk of bleeding; however, it is actually rather difficult in practice. Therefore, we propose a surgical strategy for visualizing hypervascular tumors of the posterior fossa utilizing indocyanine green (ICG). CASE DESCRIPTION: Case 1 involved a 48-year-old male with a history of von Hippel-Lindau (VHL) disease. Magnetic resonance imaging (MRI) revealed a solid tumor measuring 3.0 cm in diameter in the right cerebellopontine angle. We performed surgery because the tumor was pressing against the brainstem. Surgery was performed via the posterior subtemporal transtentorial approach in order to visualize the feeding artery and draining vein intraoperatively. The vessels were confirmed by ICG and the tumor was removed en bloc. Case 2 involved a 30-year-old woman. Signs of increased intracranial pressure were noted, and an MRI revealed a solid tumor 3.5 cm in diameter in the left cerebellar hemisphere. Surgery was performed via the midline suboccipital approach. Similarly, we confirmed the vessels using ICG and the tumor was removed en bloc. CONCLUSIONS: For hypervascular tumors of the posterior fossa, preoperative image assessment is important. Furthermore, the use of ICG during surgery is advantageous for surgical strategies where the feeding arteries and draining veins exist superficially in the operative field and are therefore easier to remove en bloc.

Cerebellar Contribution to Pattern Separation of Human Hippocampal Memory Circuits.

The cerebellum is a crucial structure for cognitive function as well as motor control. Benign brain tumors such as schwannomas, meningiomas, and epidermoids tend to occur in the cerebellopontine angle cisterns and may cause compression of the posterior lateral cerebellum near the superior posterior fissure, where the eloquent area for cognitive function was recently identified. The present study examined cognitive impairment in patients with benign cerebellar tumors before and after surgical intervention in order to clarify the functional implications of this region in humans. Patients with cerebellar tumors showed deficits in psychomotor speed and working memory compared with healthy controls. Moreover, these impairments were more pronounced in patients with right cerebellar tumors. Functional magnetic resonance imaging during performance of a lure task also demonstrated that cerebellar tumors affected pattern separation or the ability to distinguish similar experiences of episodic memory or events with discrete, non-overlapping representations, which is one of the important cognitive functions related to the hippocampus. The present findings indicate that compression of the human posterior lateral cerebellum affects hippocampal memory function.

Progression of cerebellar chronic encapsulated expanding hematoma during late pregnancy after gamma knife radiosurgery for arteriovenous malformation.

BACKGROUND: The etiology and appropriate management strategy of chronic encapsulated expanding hematoma during pregnancy after gamma knife radiosurgery for arteriovenous malformation (AVM) remain unclear. CASE DESCRIPTION: A 34-year-old female developed chronic encapsulated expanding hematoma during late pregnancy, after angiographic disappearance of cerebellar AVM following two courses of gamma knife radiosurgery. The present case implicates pregnancy as a potential promoter of growth and enlargement of chronic encapsulated expanding hematoma, which may become life-threatening and require surgical intervention. CONCLUSION: Immediate surgical management after delivery may be associated with a favorable outcome, so close follow-up management and patient education are very important in women planning pregnancy.

Hyperperfusion syndrome after stent placement for subclavian artery stenosis: case report.

A 60-year-old woman presented with a rare case of hyperperfusion syndrome after stent placement for subclavian artery stenosis manifesting as dizziness due to vertebrobasilar insufficiency. Three days after undergoing stent placement to treat the severely stenotic (90%) right subclavian artery, she suffered intracranial hemorrhage related to hyperperfusion syndrome. Preoperative single-photon emission computed tomography findings of low cerebral perfusion and poor perfusion reserve might indicate the possibility of hyperperfusion syndrome after stenting in patients with subclavian artery stenosis.

Reversibility of cognitive disorder after treatment of dural arteriovenous fistulae.

INTRODUCTION: Dural arteriovenous fistulae (DAVF) occasionally lead to cognitive disorders whose reversibility after DAVF treatment remains unclear. We studied changes on pre- and post-treatment magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT) scans in ten patients with cognitive disorder due to DAVF. METHODS: We studied the symptoms, pre- and post-treatment MRI scans, SPECT findings, and mini-mental state examination (MMSE) and treatment results in ten patients with cognitive disorder due to DAVF. They were divided into two groups; the post-treatment MMSE score exceeded 25 points in group 1 (n = 6) and was lower than 24 points in group 2 (n = 4). RESULTS: In the six group 1 patients, pretreatment diffusion-weighted images (DWI) showed hyperintense areas, and SPECT scans demonstrated the preservation of vasoreactivity after acetazolamide challenge. In the four group 2 patients, pretreatment SPECT demonstrated hypoperfusion areas that coincided with the hyperintense areas seen on DWI; there were areas with marked disturbance in vasoreactivity. The post-treatment MMSE score in groups 1 and 2 improved by 13.7 +/- 2.4 and 3.8 +/- 1.0 points, respectively; the difference was significant at p < 0.01. CONCLUSION: In patients with cognitive disorder due to DAVF, the preservation of vasoreactivity on SPECT after acetazolamide challenge indicates that their cognitive disorder may be reversible by DAVF treatment.