Epidemiology of autoimmune encephalitis and comparison to infectious causes-Experience from a tertiary center.

OBJECTIVES: The incidence of autoimmune encephalitis (AIE) has risen in the last decade, yet recent studies are lacking. We compared the epidemiology of autoimmune and infectious encephalitis cases in Tel-Aviv Sourasky Medical Center (TASMC) between 2010 and 2020. METHODS: All encephalitis cases, aged 18 and above, admitted to TASMC between the years 2010 and 2020 were reviewed for demographic, clinical, laboratory, and imaging data and categorized based on etiology. RESULTS: Two hundred and twenty-five patients with encephalitis were identified. The most common identifiable cause was viral (42%), followed by autoimmune encephalitis (35%), bacterial (18%), and fungal/parasitic (5%). The incidence of AIE cases out of the yearly admitted cases increased substantially, from 3.8/100 K in 2010 to 18.8/100 K in 2020. The incidence of viral cases also increased while those of bacterial and fungal/parasitic infections remained stable. Patients with AIE were younger compared to infectious patients (p-value <0.001) and had lower markers of systemic and cerebrospinal fluid inflammation (p-value for all <0.001). Seizures were more common among AIE patients (p-value <0.001), yet one-year mortality rates were higher among infectious patients (p-value <0.001). INTERPRETATION: AIE incidence has risen significantly in our institution during the past decade, with current rates comparable to those of all infectious causes combined. Based on this cohort, clinical clues for an autoimmune etiology include a non-inflammatory cerebrospinal fluid profile, the presence of seizures, and temporal lobe imaging abnormalities (also common in herpetic encephalitis). In light of its rising incidence and the importance of early treatment, AIE should be considered in the differential diagnosis of all encephalitis cases.

The natural history study of preclinical genetic Creutzfeldt-Jakob Disease (CJD): a prospective longitudinal study protocol.

BACKGROUND: Creutzfeldt-Jakob Disease (CJD) is the most common prion disease in humans causing a rapidly progressive neurological decline and dementia and is invariably fatal. The familial forms (genetic CJD, gCJD) are caused by mutations in the PRNP gene encoding for the prion protein (PrP). In Israel, there is a large cluster of gCJD cases, carriers of an E200K mutation in the PRNP gene, and therefore the largest population of at-risk individuals in the world. The mutation is not necessarily sufficient for the formation and accumulation of the pathological prion protein (PrPsc), suggesting that other, genetic and non-genetic factors affect the age at symptoms onset. Here we present the protocol of a cross-sectional and longitudinal natural history study of gCJD patients and first-degree relatives of gCJD patients, aiming to identify biological markers of preclinical CJD and risk factors for phenoconversion. METHODS: The study has two groups: Patients diagnosed with gCJD, and first-degree healthy relatives (HR) (both carriers and non-carriers of the E200K mutation in the PRNP gene) of patients diagnosed with gCJD. At baseline, and at the end of every year, healthy participants are invited for an "in-depth" visit, which includes a clinical evaluation, blood and urine collection, gait assessment, brain MRI, lumbar puncture (LP), and Polysomnography (PSG). At 6 months from baseline, and then halfway through each year, participants are invited for a "brief" visit, which includes a clinical evaluation, short cognitive assessment, and blood and urine collection. gCJD patients will be invited for one "in-depth" visit, similar to the baseline visit of healthy relatives. DISCUSSION: This continuous follow-up of the participants and the frequent assessments will allow early identification and diagnosis in case of conversion into disease. The knowledge generated from this study is likely to advance the understanding of the underlying clinicopathological processes that occur at the very beginning of CJD, as well as potential genetic and environmental risk factors for the development of the disease, therefore advancing the development of safe and efficient interventions. TRIAL REGISTRATION: The study is an observational study. It has registered retrospectively in https://clinicaltrials.gov/ and has been assigned an identification number NCT05746715.

New Insights on DR and DQ Human Leukocyte Antigens in Anti-LGI1 Encephalitis.

BACKGROUND AND OBJECTIVES: To explore the clinical characteristics and HLA associations of patients with anti-leucine-rich glioma-inactivated 1 encephalitis (LGI1E) from a large single center in Israel. Anti-LGI1E is the most commonly diagnosed antibody-associated encephalitic syndrome in adults. Recent studies of various populations reveal significant associations with specific HLA genes. We examined the clinical characteristics and HLA associations of a cohort of Israeli patients. METHODS: Seventeen consecutive patients with anti-LGI1E diagnosed at Tel Aviv Medical Center between the years 2011 and 2018 were included. HLA typing was performed using next-generation sequencing at the tissue typing laboratory of Sheba Medical Center and compared with data from the Ezer Mizion Bone Marrow Donor Registry, containing over 1,000,000 samples. RESULTS: Our cohort displayed a male predominance and median age at onset in the 7th decade, as previously reported. The most common presenting symptom was seizures. Notably, paroxysmal dizziness spells were significantly more common than previously reported (35%), whereas faciobrachial dystonic seizures were found only in 23%. HLA analysis revealed overrepresentation of DRB1*07:01 (OR: 3.18, CI: 20.9 p < 1.e-5) and DRB1*04:02 (OR: 3.8, CI: 20.1 p < 1.e-5), as well as of the DQ allele DQB1*02:02 (OR: 2.8, CI: 14.2 p < 0.0001) as previously reported. A novel overrepresentation observed among our patients was of the DQB1*03:02 allele (OR: 2.3, CI: 6.9 p < 0.008). In addition, we found DR-DQ associations, among patients with anti-LGI1E, that showed complete or near-complete linkage disequilibrium (LD). By applying LD analysis to an unprecedentedly large control cohort, we were able to show that although in the general population, DQB*03:02 is not fully associated with DRB1*04:02, in the patient population, both alleles are always coupled, suggesting the DRB1*04:02 association to be primary to disease predisposition. In silico predictions performed for the overrepresented DQ alleles reveal them to be strong binders of LGI1-derived peptides, similarly to overrepresented DR alleles. These predictions suggest a possible correlation between peptide binding sites of paired DR-DQ alleles. DISCUSSION: Our cohort presents distinct immune characteristics with substantially higher overrepresentation of DRB1*04:02 and slightly lower overrepresentation of DQB1*07:01 compared with previous reports implying differences between different populations. DQ-DR interactions found in our cohort may shed additional light on the complex role of immunogenetics in the pathogenesis of anti-LGI1E, implying a possible relevance of certain DQ alleles and DR-DQ interactions.

Model-free dynamic contrast-enhanced MRI analysis: differentiation between active tumor and necrotic tissue in patients with glioblastoma.

OBJECTIVE: Treatment response assessment in patients with high-grade gliomas (HGG) is heavily dependent on changes in lesion size on MRI. However, in conventional MRI, treatment-related changes can appear as enhancing tissue, with similar presentation to that of active tumor tissue. We propose a model-free data-driven method for differentiation between these tissues, based on dynamic contrast-enhanced (DCE) MRI. MATERIALS AND METHODS: The study included a total of 66 scans of patients with glioblastoma. Of these, 48 were acquired from 1 MRI vendor and 18 scans were acquired from a different MRI vendor and used as test data. Of the 48, 24 scans had biopsy results. Analysis included semi-automatic arterial input function (AIF) extraction, direct DCE pharmacokinetic-like feature extraction, and unsupervised clustering of the two tissue types. Validation was performed via (a) comparison to biopsy result (b) correlation to literature-based DCE curves for each tissue type, and (c) comparison to clinical outcome. RESULTS: Consistency between the model prediction and biopsy results was found in 20/24 cases. An average correlation of 82% for active tumor and 90% for treatment-related changes was found between the predicted component and population-based templates. An agreement between the predicted results and radiologist's assessment, based on RANO criteria, was found in 11/12 cases. CONCLUSION: The proposed method could serve as a non-invasive method for differentiation between lesion tissue and treatment-related changes.

BV-GAN: 3D time-of-flight magnetic resonance angiography cerebrovascular vessel segmentation using adversarial CNNs.

Purpose: Cerebrovascular vessel segmentation is a key step in the detection of vessel pathology. Brain time-of-flight magnetic resonance angiography (TOF-MRA) is a main method used clinically for imaging of blood vessels using magnetic resonance imaging. This method is primarily used to detect narrowing, blockage of the arteries, and aneurysms. Despite its importance, TOF-MRA interpretation relies mostly on visual, subjective assessment performed by a neuroradiologist and is mostly based on maximum intensity projections reconstruction of the three-dimensional (3D) scan, thus reducing the acquired spatial resolution. Works tackling the central problem of automatically segmenting brain blood vessels typically suffer from memory and imbalance related issues. To address these issues, the spatial context of the segmentation consider by neural networks is typically restricted (e.g., by resolution reduction or analysis of environments of lower dimensions). Although efficient, such solutions hinder the ability of the neural networks to understand the complex 3D structures typical of the cerebrovascular system and to leverage this understanding for decision making. Approach: We propose a brain-vessels generative-adversarial-network (BV-GAN) segmentation model, that better considers connectivity and structural integrity, using prior based attention and adversarial learning techniques. Results: For evaluations, fivefold cross-validation experiments were performed on two datasets. BV-GAN demonstrates consistent improvement of up to 10% in vessel Dice score with each additive designed component to the baseline state-of-the-art models. Conclusions: Potentially, this automated 3D-approach could shorten analysis time, allow for quantitative characterization of vascular structures, and reduce the need to decrease resolution, overall improving diagnosis cerebrovascular vessel disorders.

The importance of tissue-based assay in the diagnosis of autoimmune encephalitis.

BACKGROUND: The evaluation of autoimmune encephalitis (AIE) usually includes antibody testing with commercial kits capable of detecting only preselected antibodies. A non-antigen-specific assay may help detect other antibodies. In this study, we evaluate the utility and clinical relevance of an immunofluorescence assay (IFA) in the evaluation of AIE. METHODS: Immunofluorescence assay was performed on 1949 patients' serum/CSF between 2017 and 2020 and clinical relevance was designated to each case based on clinical course, suggested criteria and ancillary testing. RESULTS: Sixty-one patients (3.1%) had positive serum IFA, positive CSF, or both. Twenty-eight out of 42 patients who were positive only on IFA were designated as clinically relevant (67%), 8 inconclusive (19%), and 6 non-relevant (14%). Pleocytosis was significantly higher in the clinically relevant cases (74% vs. 20% for non-clinically relevant cases). Encephalopathy was the most common presentation (36%), followed by cerebellar syndrome (32%) and seizures (25%). The initial diagnosis changed due to IFA results in 13/28 (46%) cases and IFA result led to the initiation or modification of treatment in all cases (68% and 43%, respectively). Twenty-five patients were treated with 1st line immunotherapy and 12 with 2nd line immunotherapy, with 92% responding to treatment. Twenty-six clinically relevant patients underwent cancer workup: seven (25%) had confirmed malignancy and three had high suspicion of malignancy (total of 37%). CONCLUSION: Non-antigen-specific assays, such as IFA, can identify antibodies not detected in commercially available kits and therefore are recommended in the evaluation of autoimmune encephalitis.

PD-1-inhibitor-induced PCA-2 (MAP1B) Autoimmunity in a Patient with Renal Cell Carcinoma.

Immune check point inhibitors (ICIs) are a group of anti-cancer pharmacological agents which modify T cell activity in order to potentiate an effective immune response against tumor cells. While these drugs prove extremely potent against several types of malignancies, they may be associated with significant autoimmune adverse events. We report a patient who developed a subacute cerebellar syndrome shortly after starting treatment with nivolumab, a PD-1 inhibitor, for renal clear cell carcinoma, with detectable paraneoplastic PCA-2 antibodies. The tumor specimen stained positively for MAP1B, the antigen of PCA-2. The patient responded well to treatment with glucocorticosteroids. This is the first case to our knowledge of PCA-2 paraneoplastic cerebellar degeneration associated with ICI use, which presents in a patient with a malignancy not typically associated with neurological paraneoplastic phenomena. Treatment with immune checkpoint inhibitors (ICIs) is extremely effective in potentiating an immune response against tumor cells, but bears a substantial risk for the development of autoimmune phenomena, including paraneoplastic neurological syndromes. Increasing use of ICIs is leading to increasing numbers of patients with new-onset neurological symptoms. Awareness of these novel entities will aid in early diagnosis and proper treatment.

Adopting MR-guided stereotactic laser ablations for epileptic lesions: initial clinical experience and lessons learned.

OBJECTIVE: MR-guided laser interstitial thermal therapy (MRgLITT) is a minimally invasive technique for ablating brain lesions under real-time MRI feedback and control of the ablation process. The Medtronic Visualase system was recently approved for use in Europe and Israel. We report our initial technical experience using the system in the first 16 cases in which the system was used to ablate focal epileptogenic lesions. METHODS: We included all consecutive patients with intractable epilepsy who underwent MRgLITT procedures between 2018 and 2020. We reviewed medical charts and imaging studies of patients. Post-ablation MRIs were used to calculate ablation volumes. RESULTS: Seventeen MRgLITT procedures were performed in 16 patients. One cooling catheter/laser fiber assemblies were placed per patient. Indications for surgery were intractable epilepsy due to TLE (n = 7), suspected low-grade glioma (n = 4), radiological cortical dysplasia (n = 1), hypothalamic hamartoma (n = 1), and MR-negative foci (n = 3). Ablations were made using 30 to 70% of the maximal energy of the Visualase system. We used serial ablations as needed along the tract of the catheter by pulling back the optic fiber; the length of the lesion ranged between 7.4 and 38.1 mm. Ablation volume ranged between 0.27 and 6.78 mm3. Immediate post-ablation MRI demonstrated good ablation of the epileptic lesion in 16/17 cases. In one case with mesial temporal sclerosis, no ablation was performed due to suboptimal position of the catheter. That patient was successfully reoperated at a later date. Mean follow-up was 14.9 months (± 11.6 months). Eleven patients had follow-up longer than 12 months. Good seizure control (Engel I, A) was achieved in 7/11 patients (63%) and 1/11 (9%) had significant improvement in seizure frequency (Angle IIIa). Three patients (27%) did not experience improvement in their seizure frequency (Engel IV, B), and one of these patients died during the follow-up period from sudden unexpected death of epilepsy (SUDEP). No immediate or delayed neurological complications were documented in any of the cases during the follow-up period. CONCLUSIONS: MRgLITT is a promising technique and can be used safely as an alternative to open resection in both lesional and non-lesional intractable epilepsy cases. In our local series, the success rate of epilepsy surgery was comparable to recent publications.

Interictal Epileptiform Discharge Dynamics in Peri-sylvian Polymicrogyria Using EEG-fMRI.

Polymicrogyria (PMG) is a common malformation of cortical development associated with a higher susceptibility to epileptic seizures. Seizures secondary to PMG are characterized by difficult-to-localize cerebral sources due to the complex and widespread lesion structure. Tracing the dynamics of interictal epileptiform discharges (IEDs) in patients with epilepsy has been shown to reveal the location of epileptic activity sources, crucial for successful treatment in cases of focal drug-resistant epilepsy. In this case series IED dynamics were evaluated with simultaneous EEG-fMRI recordings in four patients with unilateral peri-sylvian polymicrogyria (PSPMG) by tracking BOLD activations over time: before, during and following IED appearance on scalp EEG. In all cases, focal BOLD activations within the lesion itself preceded the activity associated with the time of IED appearance on EEG, which showed stronger and more widespread activations. We therefore propose that early hemodynamic activity corresponding to IEDs may hold important localizing information potentially leading to the cerebral sources of epileptic activity. IEDs are suggested to develop within a small area in the PSPMG lesion with structural properties obscuring the appearance of their electric field on the scalp and only later engage widespread structures which allow the production of large currents which are recognized as IEDs on EEG.

An uncommon presentation of paraneoplastic limbic encephalitis.

Paraneoplastic limbic encephalitis (PLE) is a rare disease with established diagnostic criteria. We describe a case of an uncommon presentation of PLE in a female who presented with a one- year duration of short-term memory loss and mild behavioral changes who was eventually diagnosed with PLE associated with breast cancer. Our case demonstrates atypical presentation of PLE, with chronic presentation and an uncharacteristic mild neurological symptoms. This case aims to highlight the importance of a diagnostic work up of autoimmune encephalitis in selected cases that does not present with common diagnostic criteria.

Low cerebrospinal fluid volume and the risk for post-lumbar puncture headaches.

BACKGROUND: Cerebrospinal fluid (CSF) is essential for the medical workup of patients with neurological conditions and for disease-modifying clinical trials. Post- lumbar puncture (LP) headache is influenced by both operator and patient-related factors, including needle type and gauge, age, and gender. OBJECTIVES: We aimed to assess whether CSF volume measured based on pre-procedural brain MRI is associated with the risk of developing a post-LP headache. METHODS: In total, n = 117 participants (n = 58 Parkinson's disease patients, and n = 59 healthy controls) underwent an LP and CSF collection. Of those, n = 89 underwent MRI scans prior to the LP procedure acquiring high-resolution 3D magnetization-prepared rapid gradient echo (MP-RAGE) T1-weighted images using a 3 T MR scanner. Clinical and behavioral assessments were performed for all participants, and CSF was assessed for content. The T1-weighted images were segmented producing gray matter, white matter, and CSF probability maps. RESULTS: Thirteen participants (11.1%) experienced post-LP headache. They were younger (p = .033) and had lower CSF volumes (p = .040) compared to participants that did not develop a post LP headache. CONCLUSIONS: The results of this pilot study suggest that low CSF volumes might increase the risk for the occurrence of post-LP adverse events and should be taken into consideration when planning LP's.

Preoperative localization of seizure onset zones by magnetic source imaging, EEG-correlated functional MRI, and their combination.

OBJECTIVE: Preoperative localization of seizure onset zones (SOZs) is an evolving field in the treatment of refractory epilepsy. Both magnetic source imaging (MSI), and the more recent EEG-correlated functional MRI (EEG-fMRI), have shown applicability in assisting surgical planning. The purpose of this study was to evaluate the capability of each method and their combination in localizing the seizure onset lobe (SL). METHODS: The study included 14 patients who underwent both MSI and EEG-fMRI before undergoing implantation of intracranial EEG (icEEG) as part of the presurgical planning of the resection of an epileptogenic zone (EZ) during the years 2012-2018. The estimated location of the SL by each method was compared with the location determined by icEEG. Identification rates of the SL were compared between the different methods. RESULTS: MSI and EEG-fMRI showed similar identification rates of SL locations in relation to icEEG results (88% ± 31% and 73% ± 42%, respectively; p = 0.281). The additive use of the coverage lobes of both methods correctly identified 100% of the SL, significantly higher than EEG-fMRI alone (p = 0.039) and nonsignificantly higher than MSI (p = 0.180). False-identification rates of the additive coverage lobes were significantly higher than MSI (p = 0.026) and EEG-fMRI (p = 0.027). The intersecting lobes of both methods showed the lowest false identification rate (13% ± 6%, p = 0.01). CONCLUSIONS: Both MSI and EEG-fMRI can assist in the presurgical evaluation of patients with refractory epilepsy. The additive use of both tests confers a high identification rate in finding the SL. This combination can help in focusing implantation of icEEG electrodes targeting the SOZ.

Neurosyphilis presenting as cranial nerve palsy, an entity which is easy to miss.

Neurosyphilis is a rare disease that until the 2000s was almost eradicated due to population awareness of HIV and efficient treatment. Since then, the prevalence of the entity is rising due to risk-associated behaviour such as unprotected intercourse. Neurosyphilis is still a difficult entity to diagnose especially when combined with acute HIV infection which can influence the usual clinical course of disease. In rare occasions, both acute HIV and early syphilis infection can present as mono or multiple cranial nerve palsies. This case demonstrates a rare manifestation of misdiagnosed early syphilis infection combined with acute HIV infection in a 34-year-old man with prior history of unprotected sex with men.

Plurihormonal Pituitary Tumor of Pit-1 and SF-1 Lineages, with Synchronous Collision Corticotroph Tumor: a Possible Stem Cell Phenomenon.

Thyrotropin (TSH)-secreting pituitary tumors are the rarest functioning pituitary tumors. Nonetheless, they are not infrequently plurihormonal, as they may express/secrete hormones made by other pituitary cells derived from the Pit-1 lineage such as growth hormone (GH), prolactin (PRL), and α-subunit (αSU). However, adrenocorticotropin (ACTH) or gonadotropin secretion by such a tumor is exceptional. Although double pituitary tumors are rare, they often combine ACTH and GH secretion. A 41-year-old presented almost 2 years after delivering her 10th child; she had thyrotoxicosis (goiter and palpitations) masquerading as autoimmune postpartum thyroiditis. She was still breastfeeding and amenorrheic. She proved to have TSH, GH, PRL, and ACTH hypersecretion. Imaging revealed an invasive pituitary macrotumor. She had stigmata neither of Cushing's disease nor of acromegaly. Prior to surgery, hormonal control was achieved for close to 1 year by combined octreotide and cabergoline treatment with significant shrinking of the tumor. Following surgery, pathology revealed a collision tumor; the dominant lesion was positive for GH, ßTSH, ßFSH, and αSU and expressed both Pit-1 and SF-1.The smaller lesion was a corticotroph tumor. We report an unusual plurihormonal tumor co-expressing Pit-1 and SF-1 along with hormones made by cells of both lineages. Its simultaneous occurrence adjacent to a corticotroph tumor raises questions regarding the pathogenesis of these tumors. We propose the possibility of a stem cell tumor with multiple lineage differentiation. We hypothesize that pregnancy might have played a permissive role in tumorigenesis.

Repeatability of dynamic contrast enhanced vp parameter in healthy subjects and patients with brain tumors.

PURPOSE: To study the repeatability of plasma volume (vp) extracted from dynamic-contrast-enhanced (DCE) MRI in order to define threshold values for significant longitudinal changes, and to assess changes in patients with high-grade-glioma (HGG). METHODS: Twenty eight healthy subjects, of which eleven scanned twice, were used to assess the repeatability of vp within the normal-appearing brain tissue and to define threshold values for significant changes based on least-detected-differences (LDD) of mean vp values and histogram comparisons using earth-mover's-distance (EMD). Sixteen patients with HGG were scanned longitudinally with eight patients scanned before and following bevacizumab therapy. Longitudinal changes were assessed based on defined threshold values in comparison to RANO criteria. RESULTS: The threshold values for significant changes were: LDD = 0.0024 (ml/100 ml, 21%) for mean vp and EMD = 4.14. In patients, in 20/24 comparisons, no significant longitudinal changes were detected for vp within the normal-appearing brain tissue. Concurring results were obtained between changes in lesion volume (RANO criteria) and LDD or EMD values in cases diagnosed with progressive-disease, yet in about 50% of cases diagnosed with partial-response preliminary results demonstrated significant increase in vp despite significant reductions in lesion volume. In two patients, these changes preceded progression detected at follow-up scans. In general, a good concordance was obtained between LDD and EMD. CONCLUSION: This study shows high repeatability of vp and provides threshold values for significant changes in longitudinal assessment of patients with brain tumors. Preliminary results suggest the use of vp-DCE parameter to improve assessment of therapy response in patients with high-grade-glioma.

Differentiation between vasogenic edema and infiltrative tumor in patients with high-grade gliomas using texture patch-based analysis.

BACKGROUND: High-grade gliomas (HGGs) induce both vasogenic edema and extensive infiltration of tumor cells, both of which present with similar appearance on conventional MRI. Using current radiological criteria, differentiation between these tumoral and nontumoral areas within the nonenhancing lesion area remains challenging. PURPOSE: To use radiomics patch-based analysis, based on conventional MRI, for the classification of the nonenhancing lesion area in patients with HGG into tumoral and nontumoral components. STUDY TYPE: Prospective. SUBJECTS: In all, 179 MRI scans were obtained from 102 patients: 67 patients with HGG and 35 patients with brain metastases. A subgroup of 15 patients with HGG were scanned before and following administration of bevacizumab. FIELD STRENGTH/SEQUENCE: Pre and postcontrast agent T1 -weighted-imaging (WI), T2 WI, FLAIR, diffusion-tensor-imaging (DTI), and dynamic-contrast-enhanced (DCE)-MRI at 3T. ASSESSMENT: A total of 225 histograms and gray-level-co-occurrence matrix-based features were extracted from the nonenhancing lesion area. Tumoral volumes of interest (VOIs) were defined at the peritumoral area in patients with HGG; nontumoral VOIs were defined in patients with brain metastasis. Twenty machine-learning algorithms including support-vector-machine (SVM), k-nearest neighbor, decision-trees, and ensemble classifiers were tested. The best classifier was trained on the entire labeled data, and was used to classify the entire data. STATISTICAL TESTS: Dimensional reduction was performed on the 225 features using principal component analysis. Classification results were evaluated based on the sensitivity, specificity, and accuracy of each of the 20 classifiers, first based on a training and testing dataset (80% of the labeled data) in a 5-fold manner, and next by applying the best classifier to the validation data (the remaining 20% of the labeled data). Results were additionally evaluated by assessing differences in dynamic-contrast-enhanced plasma-volume (vp ) and volume-transfer-constant (ktrans ) values between the two components using Mann-Whitney U-test/t-test. RESULTS: The best classification into tumoral and nontumoral lesion components was obtained using a linear SVM classifier, with average accuracy of 87%, sensitivity 86%, and specificity of 89% (for the training and testing data). Significantly higher vp and ktrans values (P < 0.0001) were detected in the tumoral compared to the nontumoral component. Preliminary classification results in a subgroup of patients treated with bevacizumab demonstrated a reduction mainly in the nontumoral component following administration of bevacizumab, enabling early assessment of disease progression in some patients. DATA CONCLUSION: A radiomics patch-based analysis enables classification of the nonenhancing lesion area in patients with HGG. Preliminary results were promising and the proposed method has the potential to assist in clinical decision-making and to improve therapy response assessment in patients with HGG. LEVEL OF EVIDENCE: 1 Technical Efficacy Stage 4 J. Magn. Reson. Imaging 2018.

Surgery for Recurrent High-Grade Glioma After Treatment with Bevacizumab.

BACKGROUND: Bevacizumab (BVZ) is an antiangiogenic agent approved by the Food and Drug Administration that is used for the treatment of recurrent glioblastoma. Complications related to impaired healing may adversely affect patients resected for recurrent high-grade glioma (HGG) after treatment with BVZ. OBJECTIVE: To examine the complication rate, outcome, and tumor vasculature in patients resected for recurrent HGG after treatment with BVZ. METHODS: Data were reviewed retrospectively from patients undergoing surgery for recurrent HGG after treatment with BVZ. Results were compared with a control group of recurrently operated BVZ-naïve HGG. Tumor samples and magnetic resonance imaging scans were analyzed. RESULTS: Fifteen patients underwent HGG resection after progression after BVZ. Forty-four BVZ-naïve patients who underwent surgeries for tumor recurrence were included as controls. Median time from BVZ treatment to surgery was 30 days (2-107). Median overall survival from time of tumor diagnosis was 21.0 months (12-83.0), and median survival from post-BVZ surgery was 5.0 months (2.0-19.0), compared with 8.1 months in BVZ-naïve controls measured from time of their last reoperation. Five of the 15 patients survived 6 or more months after post-BVZ surgery. Nine patients developed postsurgical complications requiring intervention. Complication rates for surgery after BVZ treatment were 66.7% compared with 38.6% in the control group (P = 0.077). We did not see overt changes in histopathology or immunohistochemistry staining; however, tumor vasculature in tumors resected after treatment with BVZ showed a significant decrease in mean vessel density. CONCLUSIONS: Surgery for recurrent HGG may be feasible in a select group of patients. Mean tumor vessel density may be decreased after treatment with BVZ.

Only White Matter Hyperintensities Predicts Post-Stroke Cognitive Performances Among Cerebral Small Vessel Disease Markers: Results from the TABASCO Study.

BACKGROUND: White matter hyperintensities (WMH) were shown to predict cognitive decline following stroke or transient ischemic attack (TIA). However, WMH are only one among other radiological markers of cerebral small vessel disease (SVD). OBJECTIVE: The aim of this study was to determine whether adding other SVD markers to WMH improves prediction of post-stroke cognitive performances. METHODS: Consecutive first-ever stroke or TIA patients (n = 266) from the Tel Aviv Acute Brain Stroke Cohort (TABASCO) study were enrolled. MRI scans were performed within seven days of stroke onset. We evaluated the relationship between cognitive performances one year following stroke, and previously suggested total SVD burden score including WMH, lacunes, cerebral microbleeds (CMB), and perivascular spaces (PVS). RESULTS: Significant negative associations were found between WMH and cognition (p < 0.05). Adding other SVD markers (lacunes, CMB, PVS) to WMH did not improve predication of post-stroke cognitive performances. Negative correlations between SVD burden score and cognitive scores were observed for global cognitive, memory, and visual spatial scores (all p < 0.05). However, following an adjustment for confounders, no associations remained significant. CONCLUSION: WMH score was associated with poor post-stroke cognitive performance. Adding other SVD markers or SVD burden score, however, did not improve prediction.

Changes in cerebral metabolism during ketogenic diet in patients with primary brain tumors: 1H-MRS study.

Normal brain cells depend on glucose metabolism, yet they have the flexibility to switch to the usage of ketone bodies during caloric restriction. In contrast, tumor cells lack genomic and metabolic flexibility and are largely dependent on glucose. Ketogenic-diet (KD) was suggested as a therapeutic option for malignant brain cancer. This study aimed to detect metabolic brain changes in patients with malignant brain gliomas on KD using proton magnetic-resonance-spectroscopy (1H-MRS). Fifty MR scans were performed longitudinally in nine patients: four patients with recurrent glioblastoma (GB) treated with KD in addition to bevacizumab; one patient with gliomatosis-cerebri treated with KD only; and four patients with recurrent GB who did not receive KD. MR scans included conventional imaging and 1H-MRS acquired from normal appearing-white-matter (NAWM) and lesion. High adherence to KD was obtained only in two patients, based on high urine ketones; in these two patients ketone bodies, Acetone and Acetoacetate were detected in four MR spectra-three within the NAWM and one in the lesion area -4 and 25 months following initiation of the diet. No ketone-bodies were detected in the control group. In one patient with gliomatosis-cerebri, who adhered to the diet for 3 years and showed stable disease, an increase in glutamin + glutamate and reduction in N-Acetyl-Aspartate and myo-inositol were detected during KD. 1H-MRS was able to detect ketone-bodies in patients with brain tumors who adhered to KD. Yet it remains unclear whether accumulation of ketone bodies is due to increased brain uptake or decreased utilization of ketone bodies within the brain.