Significant Peritumoral Edema Research Articles

Convexity Meningioma, Parasagittal Meningioma, Falx Meningioma

During surgery for meningioma, basic surgical techniques and strategies required for the removal of the tumor are common, particularly for tumors located superficially, such as convexity, parasagittal, and falx meningiomas. Four basic surgical techniques, including detachment; devascularization; debulking; and dissection should be combined and repeated in appropriate sequence, tailored to the specific conditions of each tumor. This eventually enables the total circumferential dissection of the tumor from the surrounding tissues. It is essential to retract the tumor towards the space created at the tumor center through internal debulking, rather than retracting the normal brain, to avoid damage to the surrounding brain tissue. During surgery for parasagittal meningioma with venous sinus occlusion, it is crucial to preserve the cortical veins that have developed as collateral pathways to prevent venous complications. During surgery for falx meningioma, the selection of a surgical approach including a contralateral approach based on factors such as the development of bridging veins and significant peritumoral brain edema is required. In this article, detailed surgical procedures for convexity meningioma, parasagittal meningioma, and falx meningioma were described focusing on the application of fundamental surgical techniques tailored to each tumor type.

Supratentorial hemangioblastoma: correlation between phenotype, gender and vascular territory affected.

Supratentorial hemangioblastomas are rare, vascular lesions. The presence of peri-tumoral cysts and edema has meaningful clinical, diagnostic and therapeutic implications. Nevertheless, the pathogenesis of both cyst and edema formation is not fully understood. This study sought to determine if the radiologic phenotype of supratentorial hemangioblastoma is affected by the different cerebral arterial circulations. Review of the English-language literature from 1973 to 2023 yielded 53 cases of parenchymal supratentorial hemangioblastomas eligible for analysis. Patients were divided by the vascular territorial distribution of the lesions: anterior circulation (n = 36) or posterior circulation (n = 17), and the groups were compared for demographic, clinical, radiologic and molecular variables. Univariate analyses yielded a significant difference between the groups in five variables. Cystic changes and "classic" radiological phenotype were associated with hemangioblastomas of the posterior circulation (OR = 0.19, p = 0.045 and OR = 0.287, p = 0.048, respectively), while female gender, significant peritumoral edema and purely solid phenotype were associated with hemangioblastomas of the anterior circulation (OR = 3.384, p = 0.045 and OR = 5.25, p = 0.05 and OR = 14.0, p = 0.015; respectively). On multivariate analysis, solid phenotype and female gender remained significantly associated with the anterior circulation (OR = 36.04, p = 0.014 and OR = 4.45, p = 0.045). The incidence of von-Hippel Lindau disease was higher in the anterior-circulation group. Cystic tumors were present in all females in the posterior-circulation group compared to 43.4% in the anterior-circulation group (OR = 20.714, 95% CI 1.061 to 404.122; p = 0.045). Based on historical cases of supratentorial hemangioblastoma, this study shows that different tumor phenotypes are associated with the different cerebral circulations. Gender was also associated with differences in tumor distribution and radiologic phenotype. These novel data may improve our understanding of unique vascular diseases of the central nervous system.

P19.06.B T2/FLAIR MISMATCH, SPECIFIC RADIOGENOMIC MARKER FOR A DIFFUSE LOW GRADE ASTROCYTOMA

Abstract A 36-year-old woman presented with recurring episodes of generalized tonic clonic seizures. An MRI from an outside institution demonstrated an intra-axial brain mass suspicious for a primary brain tumor. Repeat conventional and advanced MRI imaging revealed a primary brain mass centred on the left postcentral gyrus involving cortex and subcortical white matter. The lesion was homogenously hyperintense on T2-weighted imaging, and centrally iso-to hypointense on FLAIR with a rim of hyperintense signal on the FLAIR sequence. There was no significant peritumoral edema or minimal effacement of the central sulcus. No abnormal enhancement was seen post-contrast. The lesion demonstrated no reduced diffusivity on diffusion-weighted imaging. MR perfusion showed no elevation in regional cerebral blood volume or flow. Findings are most compatible with a low grade glioma. Patient underwent total surgical resection and biopsy for histopathology. Genetic sequencing revealed an IDH mutant, non 1P,19q codeleted grade II astrocytoma. The diagnosis of adult infiltrating gliomas is predicted using imaging, and confirmed by histopathology, and molecular diagnostic methods. Regardless of grade the 1st phase in glioma diagnosis and management is IDH status. A multidisciplinary approach to the diagnosis of low grade and high grade glioma including genetic and molecular analysis is essential, as different genetic and molecular subtypes have different management and prognostic implications. Conventional MRI still represents a mandatory and extremely important step in the diagnostic workflow of neuro oncological patients for preoperative diagnosis, treatment planning, and subsequent follow up. The T2/FLAIR mismatch sign describes the MRI appearance of an IDH-mutant astrocytoma that is non 1p19q codeleted, and it is considered a preoperative novel specific MRI marker for this type of diffuse astrocytoma. In this case, the MRI findings were used preoperatively as a noninvasive tool to diagnose the patient`s low grade glioma which was confirmed by subsequent histological and genetic analysis. TEACHING POINTS1. T2/FLAIR mismatch allows for pre-operative diagnosis of IDH-mutant astrocytomas with a high level of specificity.2. It is particularly helpful in distinguishing diffuse astrocytoma from an oligodendroglioma3. Conventional MR sequences can suggest the diagnosis of IDH mutant gliomas which can assist neurosurgeons in presurgical planning and can help neuro-oncologists with treatment planning including potential clinical trials.

SDPS-42 METASTATIC NON-SMALL CELL LUNG CANCER (NSCLC) AND BRAIN EDEMA: A TOPOGRAPHICAL AND CLINICOPATHOLOGIC INVESTIGATION

Abstract Tumor-associated vasogenic brain edema is a well-known contributor of morbidity and mortality in patients with metastatic disease to the brain. It is widely accepted that metastatic disease to the brain is associated with extensive edema and can cause increased symptomatology such as pain, neurologic deficit, and elevated intracranial pressure depending on extent and location. We present a retrospective artificial intelligence (AI) mediated analysis of radiological and clinicopathologic data including specific molecular markers, presenting symptoms, and tumor location of 86 patients with non-small cell carcinoma of the lung (NSCLC) and brain metastases who underwent surgical resection and were not previously on steroids. We found that overall, tumors in all locations demonstrated a mean 10:1 edema to tumor ratio (ETR) and an occipital tumor location was associated with a significantly elevated ETR. Within our cohort there were no other factors that were significantly associated with ETR. This study demonstrates a proof of concept that NSCLC is associated with significant peritumoral edema and that topographical factors may be associated with increased extent of edema.

Radiographic Differentiation of Secretory Meningiomas and WHO Grade 2 Meningiomas: When Atypical Features Are Not Always Predictive of Atypical Tumors

Secretory meningioma (SM) is a rare subtype of World Health Organization (WHO) grade 1 meningioma, associated with significant peritumoral brain edema (PTBE). Because of this, SM may be mistaken preoperatively to be a WHO grade 2 meningioma (G2M). In this study, we identified radiographic features to differentiate these 2 tumor types preoperatively to help inform surgical decision-making. We performed a retrospective review of all patients with histologically confirmed intracranial SM and G2M at a single institution from 2000 to 2019. Relevant clinic, demographic and radiographic data were collected. We performed a stepwise multivariable logistic regression to identify independent predictors of SM. A total of 43 SM and 140 G2M patients were included in this study. In multivariable analysis, severe PTBE, meaning edema size greater than tumor size (odds ratio [OR] 4.44, P= 0.01), tumor hyperintensity on fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging sequences (OR 7.80, P= 0.002), and higher normalized apparent diffusion coefficient (nADC) values (OR 1.54, P < 0.001) were strong predictors of SM. Conversely, larger tumor volume (OR 1.79 per 10 mL volumeincrease, P < 0.001) and cystic component (OR 12.50, P= 0.007) correlated with G2M. In this study, we found that preoperative FLAIR hyperintensity, severe PTBE, and higher nADC values correlated with SM pathology, and larger size and cystic component were associated with G2M. Accurate identification of SM on preoperative imaging may provide surgeons useful information in decision-making.

VEGF Inhibition Reduces Intracranial Edema Following SRS of Brain Metastases From Renal Cell Carcinoma

Optimal control of brain metastases (BM) from renal cell carcinoma (RCC) with stereotactic radiosurgery (SRS) is critical as tyrosine kinase inhibitors (TKI) and immunotherapy has significantly prolonged overall survival (OS), emphasizing the importance of minimizing potential morbidity from treatment-associated edema. Clinically, we have observed that RCC BM-associated edema seems to be less prominent when VEGF-targeted agents (VEGFi) such as axitinib are administered contemporaneously with SRS. We therefore investigated the role of VEGFi in intracranial edema reduction in pts treated with SRS.We conducted a single institution retrospective analysis of all clear cell or unknown RCC pts with BM treated with SRS from 2013 onwards. We excluded non-clear cell RCC, lack of post-SRS imaging, and failure to complete SRS. The SRS plus VEGFi cohort was defined as VEGFi within 6 months of SRS. Volumetric data was obtained from SRS plans, edema was contoured on MR Brain T2 Flair, and paired t-test was performed. Multivariate analysis for OS performed with the Cox proportional hazards model.We identified 38 pts who received 78 courses of SRS + VEGFi and 18 pts who received 29 courses of SRS alone. For the SRS + VEGFi and SRS groups, median OS was 4.1y and 6.0y, median SRS dose was 21 Gy and 27 Gy with comparable pre-SRS steroid use of 52% and 57% (HR 0.51, P = 0.200) and baseline neurologic symptoms 50% and 74% (HR 0.943, P = 0.904), respectively. Among the SRS + VEGFi group, the mean intact tumor volume decreased from pre-SRS 1.89cc to 0.42cc at 6m post-SRS, compared to a decrease from 1.82cc to 1.28cc in the SRS group. Edema volume decreased from 17.65cc to 3.28cc in the SRS + VEGFi group with an increase from pre-SRS 5.78cc to 6.39cc at 6mo post-SRS in the SRS alone group (95% CI -3.67, 1.15, P = 0.154).Despite similar pre-SRS steroid use and increased edema volume, VEGFi appeared to improve post-SRS edema with a notable reduction of neurological symptoms. Our data suggest VEGFi may offer symptomatic benefit for significant peritumoral edema even without overt disease progression, and that re-challenge or continuation of VEGFi with SRS should be considered in such patients.

Peritumoral Brain Edema and Surgical Outcome in Secretory Meningiomas: A Matched-Cohort Analysis

Secretory meningioma (SM) is a rare subtype of benign meningioma reported to cause significant peritumoral brain edema (PTBE). Therefore, patients with SM may have more severe presenting symptoms and possibly increased postoperative complications. Our aim was to perform a statistically rigorous comparison of patients with SM with other nonsecretory World Health Organization grade I meningiomas and examine PTBE, postsurgical outcomes, and recurrence in a large series of cases. A retrospective review of all patients at our institution with pathologically confirmed SM between 2000 and 2017 was performed. A control group of nonsecretory grade I meningiomas was matched 1:1 according to tumor location and size. Study groups were compared on clinical characteristics and outcomes using logistic, cumulative logit, and normal linear generalized estimating equations regression models. Fifty-five patients with SM met inclusion criteria and were matched with 55 control patients. After adjusting for size and location, the odds of a patient with SM having a more severe T2 edema grade were 8.9 (95% confidence interval, 3.8-21.1; P< 0.001) times higher, and the odds of any T2 edema were 6.2 (95% confidence interval, 2.2-17.6; P< 0.001) times higher. Significance remained even when adjusting for age. Postoperative complications, Simpson grade resection, neurologic outcome, and recurrence were not significantly different. Patients with SM have significantly greater odds of having PTBE compared with patients with nonsecretory World Health Organization grade I meningiomas of a similar size and location. Despite this situation, surgical outcome and recurrence rates are similar.

Amelioration of anosmia after removal of an olfactory groove meningioma via pterional approach

Anosmia is one of the early symptoms of olfactory groove meningiomas (OGM) and the postoperative recovery of anosmia is accepted to be unexpected. A 42-year-old female patient presented with bilateral anosmia, and visual field field defects. Radiological examination revealed a large OGM with significant peritumoral edema. The tumor was totally resected through the pterional approach, with the meticulous preservation of the left olfactory nerve. Visual field disturbances improved in the early postoperative period. Furthermore, olfaction recovered in the left nostril at the 6-month follow-up. Despite the common belief that anosmia persists after OGM surgery, with preservation of ofactory nerves, olfaction can be recovered in rare cases.

Appliance of Navigated Transcranial Magnetic Stimulation in Radiosurgery for Brain Metastases.

Navigated transcranial magnetic stimulation (nTMS) provides noninvasive visualization of eloquent brain areas. The nTMS is usually applied in presurgical planning to minimize the risk of surgery-related neurological deterioration. The aim of this study was to evaluate the usefulness of nTMS data for GammaKnife treatment planning for patients suffering from brain metastases. Motor cortex mapping with nTMS was performed in eight patients with brain metastases within or adjacent to the precentral gyrus. The nTMS data set was imported into the planning software and fused with anatomical MRI. Then contouring of the target and critical structures was performed. Treatment plans with and without visualization of the functional structures by nTMS were analyzed and compared by neurosurgeon and medical physicist. The primary motor cortex was successfully delineated even in all cases despite significant peritumoral edema. Beam shaping and combined isocenters were used for conformal dose distribution and steeper dose fall-off near the identified eloquent zone. Compared with plans without nTMS data, treatment plans with integration of cortical nTMS mapping data showed a 2% to 78% (mean, 35.2% ± 22.7%) lower 12-Gy volume within the motor cortex without reduction of the dose applied to the tumor. The presented approach allows the easy and reliable integration of neurophysiological mapping data into GammaKnife treatment plans by the standard GammaPlan software. Diminishing the dose to critical structures might help to minimize side effects and therefore improve quality of life for brain metastasis patients.

P2.14-69 Lorlatinib Rescue Therapy for Life Threatening CNS Disease in Crizotinib-Resistant ROS1-Positive Non–Small Cell Lung Cancer (NSCLC)

C-ros proto-oncogene-1 (ROS1) chromosomal translocations result in constitutively activated receptor tyrosine kinase in 1-2% of NSCLC. Although crizotinib, a first-generation Tyrosine Kinase Inhibitor (TKI) of Anaplastic Lymphoma Kinase (ALK) and ROS1 translocations, has demonstrated efficacy in treatment of ROS1 NSCLC, patients invariably acquire resistance mutations, with a high incidence of brain metastasis at relapse owing to poor CNS drug penetration. Lorlatinib is a novel, third-generation TKI with improved CNS penetration and preclinical activity against crizotinib-resistance mutations, which recently demonstrated efficacy in a phase I/II trial. We report a patient who developed secondary crizotinib-resistance and was successfully treated with lorlatinib. A 73-year-old, female, never-smoker with recently diagnosed stage-IV ROS1-rearranged NSCLC presented with refractory seizures and coma. The patient was on first-line treatment with crizotinib for 6-months, with an excellent systemic response at 2 months. Brain MRI after presentation demonstrated multiple intracranial metastasis with vasogenic edema (Fig.1A). Neurologic status was unchanged despite mannitol, steroids and anti-epileptics. As salvage therapy, the patient received bevacizumab for vasogenic edema and lorlatinib (100mg/daily). After 48-hours, substantial clinical improvement in neurologic function and mental status was observed. A repeat MRI (D+4) demonstrated a slight interval decrease in the largest metastasis and associated edema. At 1-month follow-up, the patient continued to improve clinically with no evidence of lorlatinib toxicity. Brain MRI showed a decrease in the sizes and/or resolution of all previously noted lesions and no new metastases or significant peritumoral edema (Fig.1B). Since clinical trials typically exclude patients with symptomatic, untreated CNS disease, efficacy of newer, targeted agents in mutated-NSCLC is unclear. Here we report on a patient with life threatening, acute neurologic deterioration who derived a meaningful clinical reduction in CNS lesions at 1 month, with favorable CNS response at 2 months. In addition, we observed early evidence of tumor regression on MRI after 4 days of lorlatinib therapy. Of note, her rapid clinical response may have in part been attributable to the addition of bevacizumab. Another important consideration for our patient is that she avoided whole-brain radiation in the acute setting, and its potential adverse sequalae. We note a limitation was the absence of available testing for secondary resistance mutations that developed in this patient, which was highly susceptible to lorlatinib. However, current clinical guidelines (NCCN) do not specifically recommend resistance mutation testing upon progression, and outside of a clinical trial, the current algorithm supports lorlatinib as the agent of choice post-crizotinib failure.

The magnetic resonance imaging findings and pathological features of angiomatous meningioma

Objective To study and summarize the magnetic resonance imaging (MRI) findings and pathological features of angiomatous meningioma (AM) for improving the accuracy of the preoperative diagnosis. Methods The clinical characteristics, MRI findings, intraoperative findings and pathological features of 18 patients with AM diagnosed by histopathology were retrospectively analyzed. The clinical presentations, MRI appearances, pathological and immunohistochemistry features of AM were also evaluated. Results There were 18 cases in total, including 13 supratentorial tumors and 5 infratentorial cases; 3 cases beside cerebral falx, 7 cases convexity, 3 cases cerebellum, 2 cases cerebellopontine angle area, 2 cases sellar and 1 case sphenoid ridge. Most lesions were oval in shape. 13 cases showed significant peritumoral edema. Signal-void vessels could be found within or around the tumor in 14 cases. 5 tumors had necrosis and cystic areas. Most AM presented significant heterogeneous enhancement and 16 cases showed wide attachment, including 15 cases of dural tail sign. All tumors underwent complete resection. 7 cases were sent to conduct immunohistochemical examination, including 6 cases CD34+, 7 cases CD31+, 6 cases EMA+, 6 cases Vim+, 7 cases S-100-, 6 cases GFAP-. Proliferating cell nuclear antigen Ki-67 expression was <10 % in all 7 cases. Conclusion AM has some MRI features, which can improve accuracy of preoperative diagnosis, but it still needs to be confirmed by pathology and immunohistochemistry. Key words: Angiomatous meningioma; Magnetic resonance imaging; Pathology; Immunohistochemistry

Delineation of radiation therapy target volumes for patients with postoperative glioblastoma: a review.

Glioblastoma is the most aggressive and lethal primary malignancy of the brain, and radiotherapy (RT) is a fundamental part of its treatment. However, the optimal radiation treatment conditions are still a matter of debate, and there is no clear consensus concerning the inclusion of peritumoral edema in the clinical target volume calculation. Target delineation calculations that use postoperative residual tumor and cavity volumes plus 2 cm margins result in smaller volumes of normal brain receiving high-dose irradiation, compared to calculations that include expanded edema. Smaller RT fields may be more appropriate than larger RT fields, possibly reducing the risk of late neurological deterioration, especially in patients with significant peritumoral edema. This review focuses on the factors influencing target delineation, such as peritumoral edema, failure patterns, and prognostic factors (clinical and pathological characteristics) of patients with glioblastoma. Based on this information, we make three suggestions for radiation oncologists to refer to in daily practice. Further study is necessary to investigate the unresolved problems related to routine clinical application of RT.

Corticospinal tract modeling for neurosurgical planning by tracking through regions of peritumoral edema and crossing fibers using two-tensor unscented Kalman filter tractography.

The aim of this study was to present a tractography algorithm using a two-tensor unscented Kalman filter (UKF) to improve the modeling of the corticospinal tract (CST) by tracking through regions of peritumoral edema and crossing fibers. Ten patients with brain tumors in the vicinity of motor cortex and evidence of significant peritumoral edema were retrospectively selected for the study. All patients underwent 3-T magnetic resonance imaging (MRI) including functional MRI (fMRI) and a diffusion-weighted data set with 31 directions. Fiber tracking was performed using both single-tensor streamline and two-tensor UKF tractography methods. A two-region-of-interest approach was used to delineate the CST. Results from the two tractography methods were compared visually and quantitatively. fMRI was applied to identify the functional fiber tracts. Single-tensor streamline tractography underestimated the extent of tracts running through the edematous areas and could only track the medial projections of the CST. In contrast, two-tensor UKF tractography tracked fanning projections of the CST despite peritumoral edema and crossing fibers. Based on visual inspection, the two-tensor UKF tractography delineated tracts that were closer to motor fMRI activations, and it was apparently more sensitive than single-tensor streamline tractography to define the tracts directed to the motor sites. The volume of the CST was significantly larger on two-tensor UKF than on single-tensor streamline tractography ([Formula: see text]). Two-tensor UKF tractography tracks a larger volume CST than single-tensor streamline tractography in the setting of peritumoral edema and crossing fibers in brain tumor patients.

Clinical and Radiological Characteristics of Angiomatous Meningiomas.

BackgroundAngiomatous meningioma is a rare histological subtype of meningioma. Therefore, this specific medical condition is rarely reviewed in the literature. In the present work, we report the clinical and radiological features with postoperative outcomes of angiomatous meningioma.MethodsThis retrospective study included the patients who were pathologically diagnosed with angiomatous meningioma after surgical resection between February 2010 and September 2015 in our institute. We analyzed the clinical data, radiological manifestation, treatment and prognosis of all patients.ResultsThe 15 patients (5 males and 10 females) were diagnosed with angiomatous meningioma during the study period. The median age of patients at the time of surgery was 63 years (range: 40 to 80 years). According to Simpson classification, 7, 5, and 3 patients achieved Simpson grade I, II, and IV resection, respectively. In the follow-up period, recurrence was noted in one patient. Ten out of the 15 patients showed homogeneous enhancement. Two patients demonstrated cystic changes. There was no occurrence of calcification or hemorrhage in our patients. Characteristically, 14 out of 15 patients showed signal voids of vessels. Significant peritumoral edema was observed in the majority of tumors (67%).ConclusionAngiomatous meningiomas are rare benign meningioma. Brain images of angiomatous meningioma usually demonstrate signal void signs and peritumoral edema. In the present study, angiomatous meningiomas showed good prognosis after surgical resection.

Infratentorial complications following preresection CSF diversion in children with posterior fossa tumors.

This report presents the incidence, causes, and morbidity and mortality of infratentorial complications following CSF diversion before resection in children with posterior fossa tumors. The medical records of 437 children admitted to Abo El-Reesh Pediatric University Hospital with a diagnosis of posterior fossa tumor between 2005 and 2012 were retrospectively reviewed. Seven children developed neurological deterioration following CSF diversion due to infratentorial complications. Computed tomography scans revealed intratumoral hemorrhage (ITH) in 5 cases, while upward transtentorial herniation (UTH), as evidenced by obliteration of the quadrigeminal and ambient cisterns, was diagnosed in 2 cases. Hydrocephalus was noted in 381 patients, and 301 patients underwent CSF diversion before resection. A ventriculoperitoneal (VP) shunt was used in 214 patients, and 6 children (2.8% of shunted cases) deteriorated neurologically (4 due to ITH and 2 due to UTH). Endoscopic third ventriculostomy (ETV) was performed in 87 patients, 1 of whom developed ITH (1.1% of the patients undergoing ETV). Six patients deteriorated within 8 hours (85.7%), whereas 1 patient, the only survivor, deteriorated after 24 hours. The incidence of infratentorial complications between VP shunts and ETVs was not found to be significantly different (p = 0.659). There was a higher risk of such complications in large posterior fossa tumors (diameter ≥ 4 cm) extending close to the tentorial incisura, especially in patients with severe hydrocephalus and significant peritumoral edema. Infratentorial complications (ITH and UTH) in children with posterior fossa tumors are not uncommon (2.3%) after preresection CSF diversion (VP shunt or ETV) and are associated with a very poor prognosis in most cases, even with surgical intervention.

MR imaging of intracranial hemangiopericytomas

To describe the MR features of primary intracranial hemangiopericytomas (HPCs) on conventional imaging, diffusion and MR spectroscopy and aim to determinate distinguishing features from meningiomas. From 2006 to 2012, seven patients with pathologically confirmed primary intracranial HPCs were included. The clinical data, conventional MR findings (n=7), DWI features (n=7) and MR spectroscopy (n=5) were retrospectively analyzed. ADC values of the HPCs (n=7) were measured on ADC map and were compared with that of contralateral normal white matter. Of the seven HPCs, four were anaplastic HPCs (WHO grade III) and three were HPCs (WHO grade II). MR pattern consisted in lobulated or irregular margin tumors in all cases with cross-leaf growth on both side of the falx in two cases. The lesions showed mainly iso signal (n=4) on T1 WI and heterogeneous high signal (n=5) on T2 WI. Heterogenity was mainly related to intra tumoral hemorrhage (n=4), and proeminent intratumoral flow voids (n=3). Marked heterogeneous enhancement (n=5) with dural tail (n=4) was noted. All tumours showed significant peritumoral edema. ADC values of the tumor tissue component range between 0.638 and 1.50×10(-3)mm/s(2) (average=1,02). Three grade II HPCs showed higher values compared to normal parenchyma ADC (range between 0.772 and 0.930×10(-3)mm/s(2) with average of 0.830), whereas grade III HPCs showed either equal (three cases) or decreased ADC values (one case). MRS showed in all cases markedly increased Cho with lip/lac peak, decreased Cr and almost absent NAA. High mI peak with large glutamine/glutamate were noted in the three grade II HPCs. Conventional MR pattern when combined with DWI and MRS findings are highly suggestive of HPC and appear valuable data to differentiate HPCs from meningiomas.

Optic Radiation Fiber Tractography in Glioma Patients Based on High Angular Resolution Diffusion Imaging with Compressed Sensing Compared with Diffusion Tensor Imaging - Initial Experience

ObjectiveUp to now, fiber tractography in the clinical routine is mostly based on diffusion tensor imaging (DTI). However, there are known drawbacks in the resolution of crossing or kissing fibers and in the vicinity of a tumor or edema. These restrictions can be overcome by tractography based on High Angular Resolution Diffusion Imaging (HARDI) which in turn requires larger numbers of gradients resulting in longer acquisition times. Using compressed sensing (CS) techniques, HARDI signals can be obtained by using less non-collinear diffusion gradients, thus enabling the use of HARDI-based fiber tractography in the clinical routine.MethodsEight patients with gliomas in the temporal lobe, in proximity to the optic radiation (OR), underwent 3T MRI including a diffusion-weighted dataset with 30 gradient directions. Fiber tractography of the OR using a deterministic streamline algorithm based on DTI was compared to tractography based on reconstructed diffusion signals using HARDI+CS.ResultsHARDI+CS based tractography displayed the OR more conclusively compared to the DTI-based results in all eight cases. In particular, the potential of HARDI+CS-based tractography was observed for cases of high grade gliomas with significant peritumoral edema, larger tumor size or closer proximity of tumor and reconstructed fiber tract.ConclusionsOvercoming the problem of long acquisition times, HARDI+CS seems to be a promising basis for fiber tractography of the OR in regions of disturbed diffusion, areas of high interest in glioma surgery.

Evaluation of mast cells and hypoxia inducible factor-1 expression in meningiomas of various grades in correlation with peritumoral brain edema

Meningiomas are common primary brain tumors. However, they are often complicated by significant peritumoral brain edema, which leads to surgery difficulties and prolonged hospitalization. The aim of this study was to evaluate the presence of mast cells and expression of hypoxia inducible factor-1 (HIF-1) in correlation with the grade of meningioma and presence of peritumoral brain edema. Immunohistochemistry was performed with specific antibodies against tryptase (mast cells) and HIF-1 in low grade meningiomas (estimated as G1) and high grade meningiomas (estimated as G2 or G3). Peritumoral brain edema observed in MRI was graded using Steinhoff classification. Tryptase expression was observed in 40.4 % low grade meningiomas and in 90 % high grade cases; HIF-1 in 55.7 % low grade and in 84 % high grade meningiomas. There was a statistically significant correlation between HIF-1 and tryptase expression in both groups (p = 0.003). Presence of peritumoral brain edema statistically correlated with tryptase (p = 0.001) and HIF-1 expression (p = 0.004). Mast cells as well as hypoxia are involved in meningioma progression, and may be associated with the formation of peritumoral brain edema leading to surgery complication and recovery. Therefore, they may be useful markers in predicting the clinical course of meningioma cases.

Thirty-nine cases of intracranial hemangiopericytoma and anaplastic hemangiopericytoma: A retrospective review of MRI features and pathological findings

ObjectiveTo retrospectively review the imaging features of surgically and pathologically confirmed intracranial hemangiopericytoma and anaplastic hemangiopericytoma. MethodsThirty-nine cases of surgically and pathologically confirmed hemangiopericytoma and anaplastic hemangiopericytoma were analyzed retrospectively. The MRI features were compared with pathological findings in all cases. ResultsOf the 39 cases, 21 were anaplastic hemangiopericytoma (WHO grade III) and the remaining cases were hemangiopericytoma (WHO grade II); all lesions were solitary. MRI of anaplastic hemangiopericytoma showed that 20 cases were lobulated, and nine grew cross-leaf. The lesions showed mixed iso-high-low signal (n=20) or iso-signal (n=1) on plain T1WI, and mixed high-low signal (n=20) or iso-signal (n=1) on plain T2WI. After contrast injection, marked heterogeneous enhancement was seen in 19 cases. Significant necrosis and cystic changes were seen in 16 cases, and the “dural tail sign” was found in two cases. Ten cases had bony destruction, and 16 showed significant peritumoral edema. In 18 cases of hemangiopericytoma, nine were oval-shaped and three grew cross-leaf. The lesions showed mixed iso-low signal (n=10) or iso-signal (n=8) on plain T1WI, and mixed iso-high signal (n=10) or iso-signal (n=8) on plain T2WI. After contrast injection, significant uniform enhancement was seen in 10 cases. Significant necrosis and cystic changes were seen in seven cases, and “dural tail sign” was seen in six cases. Two cases had bony destruction. No case showed significant peritumoral edema. Pathological immunohistochemical Ki67 staining showed a concentration of ∼18.4% positive cells in anaplastic hemangiopericytoma, whereas in hemangiopericytoma it was 7.12%. ConclusionImaging findings of intracranial anaplastic hemangiopericytoma had more pronounced lobulation, cross-leaf growth tendency, more and easier bleeding, more necrosis, more cystic changes giving rise to heterogeneous signals, rarer frequency of the “dural tail sign”, more damage near the skull, and more significant peritumoral edema than hemangiopericytoma. These features may help differentiate these two types of malignancy.

Aquaporin-4 expression is increased in edematous meningiomas

Peritumoral edema is frequently present in meningiomas and can result in serious morbidity and mortality. The aquaporins (AQPs) are a family of membrane protein water channels with an integral role in water transport and maintenance of fluid balance. AQP4, increased in edematous human brain tumors such as astrocytomas and metastases, is present in the astrocytic foot processes adjacent to endothelial cells and may therefore have a role in cerebral edema formation. The objective of this study is to investigate the expression of AQP4 in meningiomas and to correlate their expression with peritumoral edema. Fresh human meningioma specimens (17) were obtained and immunohistochemical staining and Western blot analysis was performed for AQP4. The peritumoral edema index (EI) was calculated based on MRI post-processed to calculate the tumor and edema volume. Overexpression of AQP4 was associated with significant peritumoral edema. Immunohistochemistry showed upregulation of AQP4 throughout the specimens. Therefore, we conclude that increased expression of AQP4 is associated with peritumoral edema in meningiomas. This suggests that AQP4 overexpression can lead to abnormal water transport and edema formation in meningiomas. The inhibition of AQP4 water channels is a potential therapeutic option to reduce the adverse effects of peritumoral edema in meningiomas.