Falx Cerebri Research Articles

Tentorium Cerebelli: Muscles, Ligaments, and Dura Mater, Part 1.

The tentorium cerebelli is an integral part of the reciprocal tension membranes that divide some brain areas: the falx cerebri, the falx cerebelli, and the diaphragma sellae. The article is divided into two parts. The first part reviews the anatomy of the tentorium cerebelli, the dura mater, and the ligaments and cervical muscles connected to the tentorium. The tentorial area may be subject to trauma or surgery and knowledge of anatomy and existing relationships is essential to better understand the clinical picture. The second part reviews the systemic relationships of the tentorium cerebelli. The neurological anatomical information, which links the tentorium to the central and peripheral nervous systems, venous brain drainage. The tentorium is not just a body segment, but a systemic communication tool.

Intracranial chondroma of the falx cerebri: A rare case report with review of literature

Intracranial chondromas are extremely rare, benign slow-growing cartilaginous tumors mostly originating from embryonic rests at sphenoethmoidal region and sometimes can originate from the falx, convexity dura, the tentorium, the choroid plexus, or the brain parenchyma. In this article, we present a 22-year-old woman with a chondroma of dural origin. The clinical, radiological, and histopathological findings along with the operative findings and postoperative course are described as well as the pertinent literature regarding intracranial chondromas is reviewed.

Anti-NMDAR encephalitis with simultaneous hypertrophic pachymeningitis in a 68-year-old male: a rare case report

BackgroundAnti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is one of the most frequent types of autoimmune encephalitis. However, the instigating mechanisms are as yet not fully ascertained. Cardinal clinical manifestations of anti-NMDAR encephalitis include acute behavioural change, psychosis, and catatonia. As the level of diagnosis increases, encephalitis becomes more common, but there are never been published in patients with anti-NMDAR encephalitis and simultaneous hypertrophic pachymeningitis.Case presentationA sixty-eight-year-old man who presented with mental, behavioral abnormalities, unstable walking, headaches, and erratic hand movements. The neuropsychiatric symptoms and cerebrospinal fluid examination was consistent with the diagnosis criteria of anti-NMDAR encephalitis. Magnetic resonance imaging of the brain showed a thickening of dura mater localized at the left tentorium cerebelli, left cerebral hemisphere, and cerebral falx; the thickening dura mater was characterized by an intense contrast enhancement after the administration of gadolinium. High doses of intravenous methylprednisolone were administrated during his hospitalization. After 5 days, the patient’s condition improved.ConclusionsWe herein describe a rare case of a 68-year-old man with anti-NMDAR encephalitis presenting with concomitant hypertrophic pachymeningitis. We systematically expounded anti-NMDAR encephalitis and hypertrophic pachymeningitis, and made bold conjectures on the etiology and pathogenesis of these two diseases, hoping to stimulate new ideas from clinicians and basic medical researchers.

Falcine Sinus and Parafalcine Collateral Veins in Meningiomas Invading the Superior Sagittal Sinus

Venous collaterals form because of occlusion of the superior sagittal sinus (SSS), thus preserving venous drainage. Previous studies have focused on the evaluation and protection of sinuses and cortical veins and have neglected the collaterals between the SSS and deep venous system, which are important for surgical planning. We aimed to study the venous compensatory patterns inside and on both sides of the cerebral falx(parafalx) in patients with meningioma invading theSSS. Conventional magnetic resonance imaging, magnetic resonance venography, and a three-dimensional reconstructed venous model of 45 patients were analyzed. The venous collateral pattern of the parafalx was divided into 4 types: A), with cerebral medial cortical vein displacement or hyperplasia; B), collaterals connect the 2 ends of the occluded segment of the SSS; C), collaterals connect the occluded segment of the SSS with the deep cerebral venous system; and D), recanalization or secondary formation of a falcine sinus. The incidence of each type in different occlusion grades and positions of the SSS was analyzed. The 4 types of venous collaterals were ranked according to their prevalence: A, 46.7%; C, 15.6%; D, 8.9%; and B, 4.4%. The collaterals of types B, C, and D were found only in patients with severe SSS occlusion, and both types C and D were found only in middle and posterior occlusions of the SSS. In meningiomas invading the SSS, especially with complete posterior SSS occlusion, the parafalcine collateral veins and falcine sinus should be evaluated preoperatively to avoid iatrogenic injury.

Segmentation-based registration of ultrasound volumes for glioma resection in image-guided neurosurgery

PurposeIn image-guided surgery for glioma removal, neurosurgeons usually plan the resection on images acquired before surgery and use them for guidance during the subsequent intervention. However, after the surgical procedure has begun, the preplanning images become unreliable due to the brain shift phenomenon, caused by modifications of anatomical structures and imprecisions in the neuronavigation system. To obtain an updated view of the resection cavity, a solution is to collect intraoperative data, which can be additionally acquired at different stages of the procedure in order to provide a better understanding of the resection. A spatial mapping between structures identified in subsequent acquisitions would be beneficial. We propose here a fully automated segmentation-based registration method to register ultrasound (US) volumes acquired at multiple stages of neurosurgery.MethodsWe chose to segment sulci and falx cerebri in US volumes, which remain visible during resection. To automatically segment these elements, first we trained a convolutional neural network on manually annotated structures in volumes acquired before the opening of the dura mater and then we applied it to segment corresponding structures in different surgical phases. Finally, the obtained masks are used to register US volumes acquired at multiple resection stages.ResultsOur method reduces the mean target registration error (mTRE) between volumes acquired before the opening of the dura mater and during resection from 3.49 mm (± 1.55 mm) to 1.36 mm (± 0.61 mm). Moreover, the mTRE between volumes acquired before opening the dura mater and at the end of the resection is reduced from 3.54 mm (± 1.75 mm) to 2.05 mm (± 1.12 mm).ConclusionThe segmented structures demonstrated to be good candidates to register US volumes acquired at different neurosurgical phases. Therefore, our solution can compensate brain shift in neurosurgical procedures involving intraoperative US data.

S9A-05 SESSION 9A: CRANIOPLASTY TRANS-CRANIOPLASTY ULTRASOUND (TCU) THROUGH CLEAR-COLORED IMPLANTS: A VALIDATED PHANTOM STUDY COMPARING IMAGES VIA ULTRASOUND, CT AND MRI

Introduction: Current methods of transcranial diagnostic ultrasound imaging are limited by the skull’s acoustic properties. Craniotomy, craniectomy and cranioplasty procedures present opportunities to circumvent these limitations by substituting autologous bone with synthetic cranial implants composed of sonolucent biomaterials. This study examined the potential to image the brain using trans-cranioplasty ultrasound (TCU) through a sonolucent cranial implant. Methods: A validated brain phantom was imaged using computer tomography (CT), magnetic resonance imaging (MRI), and ultrasound without an implant. Next, for experimental comparison, TCU was performed through a sonolucent implant composed of clear poly-methyl methacrylate (PMMA). Results: All imaging modalities successfully revealed elements of the brain phantom including the bilateral ventricular system, the falx cerebri, and a deep hyperdense mass representing a brain tumor or hematoma. Additionally, ultrasound images were captured which closely resembled axial images obtained with both CT and MRI. Conclusion: The results obtained in this first-ever, pre-clinical, phantom study suggest trans-cranioplasty ultrasound (TCU) is now a viable immediate and long-term diagnostic imaging modality deserving of further clinical investigation.

Unedited microneurosurgery of a falcotentorial meningioma

Background:Falcotentorial meningiomas are pineal region meningiomas that arise from the dura of the tentorium cerebelli and posterior part of the falx. These tumors are commonly supplied by branches of the internal carotid artery such as the meningohypophyseal trunk, inferolateral trunk, and anterior choroidal artery. Less frequently, branches of the ophthalmic artery, vertebral artery, or external carotid artery are also involved. Based on neuroimaging studies, falcotentorial meningiomas may be classified as anterior, superior, inferior, and posterior types. Here, we present an unedited microsurgical resection of a superior falcotentorial meningioma.Case Description:The patient with a meningioma of the posterior inferior falx and a minimal extension to the tentorium underwent sitting praying position and a right occipital interhemispheric approach. Strong retraction of the dura followed a superior sagittal sinus based opening. Careful microsurgical access between the medial surface of the occipital lobe and the falx toward the splenium of corpus callosum allowed us to recognize the lesion. Thus, a cottonoid placed over the cerebral surface avoiding direct contact with the bipolar forceps, and the constant separation of the falx cerebri with the aspiration tube along the access developed a proper surgical route preventing any cortical lesion. Along the approach, cerebrospinal fluid was continuously released from the pericallosal cistern as well. Once well recognized the meningioma, we proceeded with the internal decompression of the lesion using a thumb regulated suction tube and bipolar forceps. Tissue samples from the tumor were taken for the histological diagnosis, and under conventional microsurgical technique, the meningioma was completely removed by piecemeal technique. A small lateral tear on the falx required hemostatic reparation with Tachosil. Water dissection provided us a clear cleavage plane for the microsurgical dissection of the tumor and maintained a clean operative field along the procedure. Occipital arteries running over the lateral surface of the meningioma were carefully dissected and isolated from the lesion, while the deep venous system did not achieve any contact with the tumor. After the ipsilateral component of the meningioma was resected, we intent are dissecting the contralateral segments of the tumor with a curved dissector. At the last stage of the surgery, small incision at a tumor-free segment of the falx allowed us to remove the falcotentorial attachment of the lesion. Under high microscopic magnification, the remaining minimal portion of meningioma extending under the tentorium was coagulated. After complete microsurgical removal of the meningioma, careful homeostasis based on electrocoagulation surgical and Tachosil was achieved. Finally, we performed a surgical wound closure under standard technique.Conclusion:This unedited video offers all detailed aspects for an efficient and safe falcotentorial meningioma microneurosurgery.Videolink:http://surgicalneurologyint.com/videogallery/pineal-meningioma.

Abstract 484: Molecular profiling identifies a second malignancy in a patient with medulloblastoma

Abstract Medulloblastoma is a pediatric embryonal tumor that can be classified into four molecular subgroups, each derived from a different progenitor cell. It is estimated that about 30-40% of patients will relapse, typically with recurrence at the primary site and of the same molecular subgroup. We present paired tumor/normal genomic analysis of an 18 year-old male who presented with non-Wnt/non-SHH medulloblastoma at age 12 and relapsed with metastatic disease of the falx cerebri 3 years later. Combination surgery, chemotherapy, and radiation were used in treatment of the primary and recurrent tumor. At a timepoint 6 years from original diagnosis, the patient presented with a cerebellar tumor histologically described as “consistent with recurrent medulloblastoma” with comment recommending genomics to confirm. The diagnosis was made based on near identifical morphology and retention of Neu-N and Synaptophysin in the tumor (confirmed by subsequent genetic analysis). The primary tumor and the tumor occurring 6 years after the primary diagnosis were analyzed by whole exome sequencing (blood and tumor tissues) to assess for germline variants, somatic mutation, and copy number variation. We observed no pathogenic germline variants in cancer predisposition genes. The tumor mutational profiles were distinct, with only 6 (1.8%) shared somatic variants between tumors. Specimen provenance was verified by germline variation and SRY coverage. Two targetable mutations within the RAS-MAPK pathway (PTPN11 p.Glu76Lys and PIK3CA p.Gly1007Arg) were present only in the new CNS tumor. Although the primary tumor harbored isochromosome 17q and a gain of chromosome 4, these somatic chromosomal aberrations were not detected in the new CNS tumor. RNA-seq was performed on both tumors and compared to pediatric CNS tumors from the University of California Santa Cruz Treehouse Initiative (n=434). The primary tumor clustered with the medulloblastoma patients by principal component analysis while the new CNS tumor clustered with a group of gliomas and non-medulloblastoma embryonal tumors. The primary tumor displayed evidence of overexpression of Group 4 medulloblastoma genes (e.g. EOMES, RBM24, SNCAIP, and UNC5D). These genes were not overexpressed in the new CNS tumor. Enrichment of genes commonly found in gliomas (e.g. BCAN, CHI3L2, PDGFRA, and SOX2) were noted in the new CNS tumor only. In summary, tumor genomic profiling of a primary medulloblastoma and the new CNS tumor arising 6 years later revealed two distinct sets of somatic mutations suggestive of second malignancy rather than recurrence in this patient. While second malignancy in the setting of medulloblastoma is a rare event, it has been documented, both in a time period consistent with that described in our patient and in the form of glioma. Thus, tumor profiling refined diagnosis in this patient allowing for a more accurate assessment of treatment and management options. Citation Format: Kathleen M. Schieffer, Katherine E. Miller, Daniel R. Boue, Daniel C. Koboldt, Patrick Brennan, Benjamin J. Kelly, Gregory Wheeler, Vincent Magrini, Amy Wetzel, Elizabeth Varga, Devon Dishman, Kristen Leraas, Vibhuti Agarwal, Mohamed S. AbdelBaki, Jonathan L. Finlay, Jeffrey R. Leonard, Peter White, Julie M. Gastier-Foster, Catherine E. Cottrell, Elaine R. Mardis, Richard K. Wilson. Molecular profiling identifies a second malignancy in a patient with medulloblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 484.

Tailored approach for the resection of planum sphenoidale meningiomas

Background and importance. Planum sphenoidale meningiomas are relatively rare tumours that can grow to a considerable size before determining noticeable symptoms. Modern imaging techniques can detect these tumours of varying size. Surgical resection of planum sphenoidale meningiomas can be performed by adapting the approach to the size of the tumour.Clinical presentation. A 56-year-old woman presented with a small (2 cm in diameter) planum sphenoidale meningioma that was resected through a frontal craniotomy performed with a 4,5 cm trephine at the level of the frontal sinus. The second case is that of a 55-year-old woman that presented with a large planum sphenoidale meningioma (5,6 cm in the antero-posterior plane and 5,5 cm cranio-caudally) extending to the tuberculum sellae and sellar diaphragm, reaching the anterior wall of the third ventricle. In this case, a bifrontal craniotomy was performed with frontal sinus cranialization and resection of falx cerebri, achieving a Simpson II resection. Both cases presented a favourable postoperative evolution, without any deficits and an excellent cosmetic result.Conclusion. The approach for tumours of the anterior skull base must be tailored to the size of the tumour. A minimally invasive approach through the frontal sinus should not be avoided in cases with small tumours.

PB1763 CNS INVOLVEMENT AT PRESENTATION IN AML: A RETROSPECTIVE CASE SERIES

Background:Central nervous system involvement at present in Acute Myeloid Leukemia is uncommon. When it occurs, the course is less predictable and prognostication and therapy guidelines are less lucid than with acute lymphoblastic leukemia.Aims:To review the clinical profile, presentation, imaging findings, CSF positivity, management, and outcomes of AML patients with CNS involvement at the time of initial presentation.Methods:We retrospectively collected the clinicopathological profile, management and outcome data of AML patients with CNS involvement over the past 5 years at our Institute. Patients with CNS involvement by CSF positivity or direct CNS or spinal cord involvement were included. It is our policy to perform CNS evaluation at presentation in all Pediatric AML or with symptoms suggestive of CNS involvement e.g. paraparesis, seizures, proptosis.Patients with paraspinal masses causing cord compressions, intra cranial bleed, intraretinal bleed, CNS involvement at relapse, or possible CNS involvement but without either CSF or imaging confirmation were excluded.Results:Eight patients fulfilled our inclusion criteria. Of these 4 were adults and 4 were pediatric patients (<18 years age). Only 1 (12.5%) amongst these was a female. Cytogenetics were t(8:21), t(8:21) +8, t(8:21) +8 +19, AML with t(9:22) in 1 patient each with rest 50% patients having normal cytogenetics.CSF analysis was positive for malignant cells in 3 patients, not done in 1 (because patient was very sick) and negative in the rest. Imaging was not done in 2 patients who were CSF positive with no focal neurological deficits, and was normal in 1 patient with 3rd cranial nerve palsy. Leptomeningeal involvement was present in 2 patients, cavernous sinus and falx cerebri involvement in 1, paravertebral deposits and cord enhancement in 1, and paravertebral and infratemporal deposits in another.All patients were treated with 3+7 induction followed by HIDAC with IT therapy with each cycle and 2 patients received RT as well. Ph positive AML was taken up for transplant after 2nd induction with HIDAC and is currently undergoing the same. 1 patient was not given chemotherapy because she had severe fungal pneumonia and expired.Six out of the 7 treated patients showed near complete resolution of CNS symptoms/imaging findings after chemotherapy. 1 patient with paraplegia had persisting spinal cord lesions despite 2 induction chemotherapies, IT and RT. Four patients relapsed – one CNS relapse, two CNS and BM relapse and 1 patient had BM relapse in the background of persisting CNS disease. Currently only 3 patients are alive, one of whom is undergoing Allogenic HSCT.Summary/Conclusion:CNS involvement in AML is rare at presentation. Presentation can vary from asymptomatic CSF positivity, to isolated cranial nerve involvement to paraplegia and recurrent seizures. Screening and Management protocols are not clearly defined. NCCN recommends screening before first consolidation in patients with monocytic differentiation, Mixed phenotypic acute leukemia, WBC >40000at diagnosis, extra medullary disease or high risk APML. For major neurological signs imaging should be performed. If no signs or symptoms then CSF should be done. Treatment with standard AML chemotherapy with IT/RT seems to have short term effects only. Overall prognosis in this group of patients seems poor with a high rate of relapse and mortality. Larger studies are required to address relevant questions such as high risk patients who should be screened, indications of performing CSF analysis and imaging, and adequate management.image

The Supra/Infra Transtentorial Transfalcine Approach for the Removal of a Falcotentorial Meningioma: 2-Dimensional Video.

Falcotentorial meningiomas originate in the junction of the falx cerebri and the tentorium. Due to its anatomic vicinity, these tumors have a close relationship with important neurovascular structures surrounding the pineal region including the deep venous system. Surgical approaches would normally consider posterior midline corridors, but decision between supra or infratentorial access should be considered by the size, anatomic displacement of structures, and the infiltration of the dural attachment. This surgical video1,2 demonstrates the surgical technique and pearls to achieve a stepwise resection of a complex falcotentorial meningioma. We present a case of a 42-yr-old female patient, neurologically intact at presentation. A semi-sitting position was used. Appropriate management of cerebrospinal fluid was obtained with an external ventricular drainage which is kept closed until the dura is opened. A suprainfratentorial craniotomy was done with adequate exposure of the superior sagittal sinus and torcula. The supracerebellar infratentorial corridor was used for inferior internal debulking and arachnoidal dissection of the tumor while the exposure obtained in the posterior interhemispheric allowed a corridor which exposed widely the tumor with transtentorial transfalcine extension. Adequate management of adjacent structures was done while preserving the straight sinus and vein of Galen. A gross total removal of the tumor was achieved and the patient was discharged without complications. After this surgical video, the viewer will have learned the steps to safely achieve a surgical removal of a falcotentorial meningioma taking care of its relationship with the venous and neural adjacent structures.

Falx cerebri Calcifications and Ossifications in CT Scans – A Data Collection on Frequency, Position and Size

Background: The aim of this study is the acquisition of data regarding the frequency, position, size, sex- and age distribution of falx cerebri calcifications (FCC, including ossifications) using CT scans. Methods: An explorative-retrospective data collection using skull CT scans of all CT devices (in use for patient examinations) at the University Hospital Graz. From August 20 to August 31, 2015, 365 cases of undisturbed and non-contrast brain images were determined. FCC with a density threshold value of > = 100 HU was recorded, analysed according to certain target parameters and evaluated using descriptive statistics. Additionally, lateral views of three-dimensional image reconstructions of certain FCC were produced and measured. Also, superior sagittal sinus calcifications were examined. Results: The occurrence of FCC accounted for 34% in general and was slightly more frequent in older men. Among all FCC 95% were located in anterior and medial falx area. The Spearman’s rank correlation between age and occurrence of FCC was r = .96, p < .001. Considering a sagittal dimension (max. length x max. height x sin (90°-Gantry Tilt) computed in axial layers) of > = 2cm² , FCC incidences still amounted to 9, 8%. Conclusions: The FCC frequency of 10% with a size of > = 2 cm² (sagittal dimension computed in axial layers) corresponded to values of previous x-ray studies. However, the dimension or diameter was never mentioned. FCC of the size mentioned above is relevant to an osteopath’s work since they might influence the craniosacral palpation and treatment of the falx cerebri. Therefore, there is further need for investigation concerning the possible effects of FCC on craniosacral palpation of the falx cerebri, precise measurements of size, as well as a histological comparison alongside CT-imaging. Keywords: Falx cerebri, calcification, ossification, computed tomography

Cerebral cortex impairment in neuromyelitis optica spectrum disorder: A case report and literature review

BackgroundNeuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disorder of the central nervous system that usually presents with acute myelitis and/or optic neuritis. Cortical lesions used to be regarded as “red flags” of NMOSD, and indicated the possibility of alternative diagnoses. We recently had reported a NMOSD patient with weakness in both lower limbs resulting from cortical damage, which was usually attributed to spinal cord lesions. Surprisingly, we identified another patient bearing an uncanny resemblance of imaging manifestations. Cases of NMOSD with cortical impairment reported in the English language literature were reviewed and the demographic characteristics, clinical features, response to treatment, and imaging findings of these cases were analyzed. ResultsOur literature review identified other nine cases excluding our previously reported one. All patients had abnormal magnetic resonance imaging (MRI) signals findings in the cortex and leptomeninges. Eight cases reported symptoms of specific cortical impairments. Seven cases underwent follow-up MRI examination and all displayed normal images. Three cases had a previous history of Sjögren's syndrome. ConclusionsCortical impairment with leptomeningeal enhancement can be considered an imaging performance component of NMOSD. Serious damage to the blood-brain barrier and Aquaporin-4 antibody (AQP4) may be involved in the process of cortical and leptomeningeal damage. We identified the frontal lobes as being the most susceptible area, especially the cortex adjacent to the cerebral falx. NMOSD cortical lesions may be reversed by methylprednisolone and immunosuppressant treatment.

Lateral impacts correlate with falx cerebri displacement and corpus callosum trauma in sports-related concussions

Corpus callosum trauma has long been implicated in mild traumatic brain injury (mTBI), yet the mechanism by which forces penetrate this structure is unknown. We investigated the hypothesis that coronal and horizontal rotations produce motion of the falx cerebri that damages the corpus callosum. We analyzed previously published head kinematics of 115 sports impacts (2 diagnosed mTBI) measured with instrumented mouthguards and used finite element (FE) simulations to correlate falx displacement with corpus callosum deformation. Peak coronal accelerations were larger in impacts with mTBI (8592 rad/s2 avg.) than those without (1412 rad/s2 avg.). From FE simulations, coronal acceleration was strongly correlated with deep lateral motion of the falx center (r = 0.85), while horizontal acceleration was correlated with deep lateral motion of the falx periphery (r > 0.78). Larger lateral displacement at the falx center and periphery was correlated with higher tract-oriented strains in the corpus callosum body (r = 0.91) and genu/splenium (r > 0.72), respectively. The relationship between the corpus callosum and falx was unique: removing the falx from the FE model halved peak strains in the corpus callosum from 35% to 17%. Consistent with model results, we found indications of corpus callosum trauma in diffusion tensor imaging of the mTBI athletes. For a measured alteration of consciousness, depressed fractional anisotropy and increased mean diffusivity indicated possible damage to the mid-posterior corpus callosum. Our results suggest that the corpus callosum may be sensitive to coronal and horizontal rotations because they drive lateral motion of a relatively stiff membrane, the falx, in the direction of commissural fibers below.

Brain invasion and the risk of seizures in patients with meningioma.

Identification of risk factors for perioperative epilepsy remains crucial in the care of patients with meningioma. Moreover, associations of brain invasion with clinical and radiological variables have been largely unexplored. The authors hypothesized that invasion of the cortex and subsequent increased edema facilitate seizures, and they compared radiological data and perioperative seizures in patients with brain-invasive or noninvasive meningioma. Correlations of brain invasion with tumor and edema volumes and preoperative and postoperative seizures were analyzed in univariate and multivariate analyses. Totals of 108 (61%) females and 68 (39%) males with a median age of 60 years and harboring totals of 92 (52%) grade I, 79 (45%) grade II, and 5 (3%) grade III tumors were included. Brain invasion was found in 38 (22%) patients and was absent in 138 (78%) patients. The tumors were located at the convexity in 72 (41%) patients, at the falx cerebri in 26 (15%), at the skull base in 69 (39%), in the posterior fossa in 7 (4%), and in the ventricle in 2 (1%); the median tumor and edema volumes were 13.73 cm3 (range 0.81-162.22 cm3) and 1.38 cm3 (range 0.00-355.80 cm3), respectively. As expected, edema volume increased with rising tumor volume (p < 0.001). Brain invasion was independent of tumor volume (p = 0.176) but strongly correlated with edema volume (p < 0.001). The mean edema volume in noninvasive tumors was 33.0 cm3, but in invasive tumors, it was 130.7 cm3 (p = 0.008). The frequency of preoperative seizures was independent of the patients' age, sex, and tumor location; however, the frequency was 32% (n = 12) in patients with invasive meningioma and 15% (n = 21) in those with noninvasive meningioma (p = 0.033). In contrast, the probability of detecting brain invasion microscopically was increased more than 2-fold in patients with a history of preoperative seizures (OR 2.57, 95% CI 1.13-5.88; p = 0.025). In univariate analyses, the rate of preoperative seizures correlated slightly with tumor volume (p = 0.049) but strongly with edema volume (p = 0.014), whereas seizure semiology was found to be independent of brain invasion (p = 0.211). In multivariate analyses adjusted for age, sex, tumor location, tumor and edema volumes, and WHO grade, rising tumor volume (OR 1.02, 95% CI 1.00-1.03; p = 0.042) and especially brain invasion (OR 5.26, 95% CI 1.52-18.15; p = 0.009) were identified as independent predictors of preoperative seizures. Nine (5%) patients developed new seizures within a median follow-up time of 15 months after surgery. Development of postoperative epilepsy was independent of all clinical variables, including Simpson grade (p = 0.133), tumor location (p = 0.936), brain invasion (p = 0.408), and preoperative edema volume (p = 0.081), but was correlated with increasing preoperative tumor volume (p = 0.004). Postoperative seizure-free rates were similar among patients with invasive and those with noninvasive meningioma (p = 0.372). Brain invasion was identified as a new and strong predictor for preoperative, but not postoperative, seizures. Although also associated with increased peritumoral edema, seizures in patients with invasive meningioma might be facilitated substantially by cortical invasion itself. Consideration of seizures in consultations between the neurosurgeon and neuropathologist can improve the microscopic detection of brain invasion.

Embryological Consideration of Dural AVFs in Relation to the Neural Crest and the Mesoderm.

Intracranial and spinal dural arteriovenous fistulas (DAVFs) are vascular pathologies of the dural membrane with arteriovenous shunts. They are abnormal communications between arteries and veins or dural venous sinuses that sit between the two sheets of the dura mater. The dura propria faces the surface of brain, and the osteal dura faces the bone. The location of the shunt points is not distributed homogeneously on the surface of the dural membrane, but there are certain areas susceptible to DAVFs. The dura mater of the olfactory groove, falx cerebri, inferior sagittal sinus, tentorium cerebelli, and falx cerebelli, and the dura mater at the level of the spinal cord are composed only of dura propria, and these areas are derived from neural crest cells. The dura mater of the cavernous sinus, transverse sinus, sigmoid sinus, and anterior condylar confluence surrounding the hypoglossal canal are composed of both dura propria and osteal dura; this group is derived from mesoderm. Although the cause of this heterogeneity has not yet been determined, there are some specific characteristics and tendencies in terms of the embryological features. The possible reasons for the segmental susceptibility to DAVFs are summarized based on the embryology of the dura mater.

Frequent central nervous system, pachymeningeal and plexus MRI changes in POEMS syndrome

ObjectivePolyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, skin changes (POEMS) syndrome is a rare multisystem disease associated with a plasma-cell dyscrasia. Although pachymeningeal involvement has occasionally been described, MRI of the central nervous system (CNS) has not yet been extensively investigated.MethodsWe retrospectively evaluated CNS MRI in Europe’s largest single-center cohort of POEMS syndrome. Of 77 patients who have been formally diagnosed with POEMS, 41 had MRI brain and 29 had MRI spine. A control group of 33 patients with chronic inflammatory demyelinating polyneuropathy (CIDP) was used as this is the major differential diagnosis. Of these CIDP patients, 12 underwent both MRI brain and spine, 7 had solely MRI brain and 14 had MRI spine.ResultsIn 41 POEMS patients with MRI brain, we identified frequent smooth, diffuse meningeal thickening of the cerebral convexities and falx (n = 29, 71%), of which 4 had meningeal collections. 17 (41%) had vascular abnormalities including white-matter disease, of which 4 had established infarcts. Of 29 patients with MRI spine, 17 (59%) had thickening of the brachial and lumbosacral plexus. Conversely in 19 CIDP patients with MRI brain, none had meningeal thickening (p < 0.0001); however, 8 (42%) had vascular abnormalities (p = 0.85). Of 26 patients with MRI spine, 9 (35%) had brachial or lumbosacral plexus thickening (p = 0.06).ConclusionsIn contrast to CIDP, POEMS patients frequently have pachymeningeal thickening. Vascular abnormalities and plexus thickening were also common but not statistically different to CIDP.

Interdural high signal on CISS sequence: an alternative CSF pathway?

The falx cerebri, falx cerebelli, and tentorial notch exhibit a peculiar morphology with a two-layered, dural leaf that protrudes into the cranial cavity with a free edge. However, there are few studies exploring this morphology using neuroimaging techniques. The present study aimed to explore these dural structures using magnetic resonance imaging. A total of 65 outpatients were included in this study. Following initial examinations with conventional sequences, the constructive interference in steady-state (CISS) sequences were performed in thin-sliced, coronal sections. In 78% of the subjects, the interdural spaces presenting with high signal were identified in the falx cerebri. These spaces were located adjacent to the uppermost part of the falx, formed by two dural leaves and the superior sagittal sinus, and tapered downward where the leaves united to form the falx cerebri. At the tentorial notch, these spaces were found in 52% of the 65, most predominantly in the medial edge followed by the tentorium cerebelli-tentorial notch junctional region. Forty-one percent of patients had a dural opening into the cerebral cistern. The interdural spaces with high signal were not identified in the tentorium cerebelli in any of the subjects. The falx cerebri and tentorial notch form the interdural spaces that may provide alternative cerebrospinal fluid pathways. The coronal CISS sequence is suitable for delineating such interdural spaces.

Automatic and efficient MRI-US segmentations for improving intraoperative image fusion in image-guided neurosurgery.

Knowledge of the exact tumor location and structures at risk in its vicinity are crucial for neurosurgical interventions. Neuronavigation systems support navigation within the patient's brain, based on preoperative MRI (preMRI). However, increasing tissue deformation during the course of tumor resection reduces navigation accuracy based on preMRI. Intraoperative ultrasound (iUS) is therefore used as real-time intraoperative imaging. Registration of preMRI and iUS remains a challenge due to different or varying contrasts in iUS and preMRI. Here, we present an automatic and efficient segmentation of B-mode US images to support the registration process. The falx cerebri and the tentorium cerebelli were identified as examples for central cerebral structures and their segmentations can serve as guiding frame for multi-modal image registration. Segmentations of the falx and tentorium were performed with an average Dice coefficient of 0.74 and an average Hausdorff distance of 12.2 mm. The subsequent registration incorporates these segmentations and increases accuracy, robustness and speed of the overall registration process compared to purely intensity-based registration. For validation an expert manually located corresponding landmarks. Our approach reduces the initial mean Target Registration Error from 16.9 mm to 3.8 mm using our intensity-based registration and to 2.2 mm with our combined segmentation and registration approach. The intensity-based registration reduced the maximum initial TRE from 19.4 mm to 5.6 mm, with the approach incorporating segmentations this is reduced to 3.0 mm. Mean volumetric intensity-based registration of preMRI and iUS took 40.5 s, including segmentations 12.0 s.

Gorlin syndrome in a patient with skin type VI

Gorlin syndrome, also known as nevoid basal cell carcinoma syndrome, is a rare autosomal dominant disorder that is characterized by multiple basal cell carcinomas developing at a young age, keratocystic odontogenic tumors of the jaw, palmar or plantar pits, calcification of the falx cerebri, and skeletal abnormalities. Nevoid basal cell carcinoma syndrome is caused by mutations in the PTCH1 or SUFU genes. Our patient with Fitzpatrick skin type VI was diagnosed with Gorlin syndrome based on the presentation of multiple major diagnostic characteristics. Although he is 33 years old, he has not developed any multiple basal cell carcinomas to date.