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Background: Early identification of large vessel occlusion (LVO) in patients with ischemic stroke is crucial for timely interventions. We propose a machine learning-based algorithm (JLK-CTL) that uses handcrafted features from noncontrast computed tomography to predict LVO., Methods: We included patients with ischemic stroke who underwent concurrent noncontrast computed tomography and computed tomography angiography in seven hospitals. Patients from 5 of these hospitals, admitted between May 2011 and March 2015, were randomly divided into training and internal validation (9:1 ratio). Those from the remaining 2 hospitals, admitted between March 2021 and September 2021, were designated for external validation. From each noncontrast computed tomography scan, we extracted differences in volume, tissue density, and Hounsfield unit distribution between bihemispheric regions (striatocapsular, insula, M1-M3, and M4-M6, modified from the Alberta Stroke Program Early Computed Tomography Score). A deep learning algorithm was used to incorporate clot signs as an additional feature. Machine learning models, including ExtraTrees, random forest, extreme gradient boosting, support vector machine, and multilayer perceptron, as well as a deep learning model, were trained and evaluated. Additionally, we assessed the models' performance after incorporating the National Institutes of Health Stroke Scale scores as an additional feature., Results: Among 2919 patients, 83 were excluded. Across the training (n=2463), internal validation (n=275), and external validation (n=95) datasets, the mean ages were 68.5±12.4, 67.6±13.8, and 67.9±13.6 years, respectively. The proportions of men were 57%, 53%, and 59%, with LVO prevalences of 17.0%, 16.4%, and 26.3%, respectively. In the external validation, the ExtraTrees model achieved a robust area under the curve of 0.888 (95% CI, 0.850-0.925), with a sensitivity of 80.1% (95% CI, 72.0-88.1) and a specificity of 88.6% (95% CI, 84.7-92.5). Adding the National Institutes of Health Stroke Scale score to the ExtraTrees model increased sensitivity (from 80.1% to 92.1%) while maintaining specificity., Conclusions: Our algorithm provides reliable predictions of LVO using noncontrast computed tomography. By enabling early LVO identification, our algorithm has the potential to expedite the stroke workflow., Competing Interests: Disclosures P.E. Kim, D. Kim, and Dr Ryu are employees of JLK Inc. The other authors report no conflicts.

Dementia is a significant global health issue that is exacerbated by an aging population. Imaging plays an established role in the evaluation of patients with neurocognitive disorders such as dementia. In current clinical practice, magnetic resonance imaging (MRI) and positron emission tomography (PET) are primary imaging modalities used separately but in concert to help diagnose and classify dementia. The clinical applications of PET/MRI hybrid imaging in dementia are an active area of research, particularly given the continued emergence of functional MRI (fMRI) and amyloid PET tracers. This narrative review provides a comprehensive overview of the rationale and current evidence for PET/MRI hybrid dementia imaging from 2018 to 2023. Hybrid imaging offers advantages in the accuracy of characterizing neurodegenerative disorders, and future research will need to address the cost of integrated PET/MRI systems compared to stand-alone scanners, the development of new biomarkers, and image correction techniques.

Introduction: 1.5 Tesla (1.5T) remain a significant field strength for brain imaging worldwide. Recent computer simulations and clinical studies at 3T MRI have suggested that dynamic susceptibility contrast (DSC) MRI using a 30° flip angle ("low-FA") with model-based leakage correction and no gadolinium-based contrast agent (GBCA) preload provides equivalent relative cerebral blood volume (rCBV) measurements to the reference-standard acquisition using a single-dose GBCA preload with a 60° flip angle ("intermediate-FA") and model-based leakage correction. However, it remains unclear whether this holds true at 1.5T. The purpose of this study was to test this at 1.5T in human high-grade glioma (HGG) patients., Methods: This was a single-institution cross-sectional study of patients who had undergone 1.5T MRI for HGG. DSC-MRI consisted of gradient-echo echo-planar imaging (GRE-EPI) with a low-FA without preload (30°/P-); this then subsequently served as a preload for the standard intermediate-FA acquisition (60°/P+). Both normalized (nrCBV) and standardized relative cerebral blood volumes (srCBV) were calculated using model-based leakage correction (C+) with IBNeuro™ software. Whole-enhancing lesion mean and median nrCBV and srCBV from the low- and intermediate-FA methods were compared using the Pearson's, Spearman's and intraclass correlation coefficients (ICC)., Results: Twenty-three HGG patients composing a total of 31 scans were analyzed. The Pearson and Spearman correlations and ICCs between the 30°/P-/C+ and 60°/P+/C+ acquisitions demonstrated high correlations for both mean and median nrCBV and srCBV., Conclusion: Our study provides preliminary evidence that for HGG patients at 1.5T MRI, a low FA, no preload DSC-MRI acquisition can be an appealing alternative to the reference standard higher FA acquisition that utilizes a preload., Competing Interests: Author KS was employed IQ-AI Ltd and Imaging Biometrics LLC. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Shiroishi, Weinert, Cen, Varghese, Dondlinger, Prah, Mendoza, Nazemi, Ameli, Amini, Shohas, Chen, Bigjahan, Zada, Chen, Neman-Ebrahim, Chang, Chow, Fan, Yang, Attenello, Ye, Kim, Patel, Lerner, Acharya, Hu, Quarles, Boxerman, Wu and Schmainda.)

Background and Purpose: Ketogenic diet (KD) improves seizure control in patients with drug-resistant epilepsy. As increased mitochondrial levels of glutathione (GSH) might contribute to a change in seizure susceptibility, we quantified changes of absolute GSH levels in the brain by in vivo 1H magnetic resonance spectroscopy (1H MRS) and correlate that with degree of seizure control in patients on KD., Methods: Five cognitively normal adult patients with drug-resistant epilepsy were initially included and 2 completed the study. Each patient was evaluated by a neurologist and registered dietitian at baseline, 1, 3, and 6 months for seizure status and diet adherence after initiation of a modified atkins diet. Multiple metabolites including GSH were quantified using LCModel (version 6.3-1P; Stephen Provencher, Oakville, ON, CA) on a short echo time single-voxel 1H MRS in parieto/occipital grey matter and parietal white matter on a 3 Tesla General Electric magnet prior to starting the ketogenic diet and at 6 months., Results: Both patients (42-years-old male and 35-years-old female) demonstrated marked increases in absolute GSH level in both gray matter (0.12 to 1.40 and 0.10 to 0.70 international unit [IU]) and white matter (0.65 to 1.50 and 0.80 to 2.00 IU), as well as 50% improvements in seizure duration and frequency. Other metabolites including ketone bodies did not demonstrate consistent changes., Conclusions: Markedly increased levels of GSH (7-fold and 14-fold) were observed in longitudinal prospective study of two adult patients with intractable epilepsy with 50% seizure improvement after initiation of ketogenic diets. This pilot study supports the possible anticonvulsant role of GSH in the brain., Competing Interests: None., (Copyright © 2023 Korean Epilepsy Society.)

Background and Purpose: Although posttraumatic epilepsy is a common complication of traumatic brain injury, the relationship between these conditions is unclear and early posttraumatic epilepsy detection and prevention remain major unmet clinical challenges. This study aimed to identify imaging biomarkers that predict posttraumatic epilepsy among survivors of traumatic brain injury on the basis of an MR imaging data set., Materials and Methods: We performed tensor-based morphometry to analyze brain-shape changes associated with traumatic brain injury and to derive imaging features for statistical group comparison. Additionally, machine learning was used to identify structural anomalies associated with brain lesions. Automatically generated brain lesion maps were used to identify brain regions where lesion load may indicate an increased incidence of posttraumatic epilepsy. We used 138 non-posttraumatic epilepsy subjects for training the machine learning method. Validation of lesion delineation was performed on 15 subjects. Group analysis of the relationship between traumatic brain injury and posttraumatic epilepsy was performed on an independent set of 74 subjects (37 subjects with and 37 randomly selected subjects without epilepsy)., Results: We observed significant F -statistics related to tensor-based morphometry analysis at voxels close to the pial surface, which may indicate group differences in the locations of edema, hematoma, or hemorrhage. The results of the F -test on lesion data showed significant differences between groups in both the left and right temporal lobes. We also saw significant differences in the right occipital lobe and cerebellum., Conclusions: Statistical analysis suggests that lesions in the temporal lobes, cerebellum, and the right occipital lobe are associated with an increased posttraumatic epilepsy incidence., (© 2022 by American Journal of Neuroradiology.)

Radiologists must convert the complex information in head and neck imaging into text reports that can be understood and used by clinicians, patients, and fellow radiologists for patient care, research, and quality initiatives. Common data elements in reporting, through use of defined questions with constrained answers and terminology, allow radiologists to incorporate best practice standards and improve communication of information regardless of individual reporting style. Use of common data elements for head and neck reporting has the potential to improve outcomes, reduce errors, and transition data consumption not only for humans but future machine learning systems., Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Posterior reversible encephalopathy syndrome (PRES) represents a unique clinical entity with non-specific clinical symptoms and unique neuroradiological findings. This syndrome may present with a broad range of clinical symptoms from headache and visual disturbances to seizure and altered mentation. Typical imaging findings include posterior-circulation predominant vasogenic edema. Although there are many well-documented diseases associated with PRES, the exact pathophysiologic mechanism has yet to be fully elucidated. Generally accepted theories revolve around disruption of the blood-brain barrier secondary to elevated intracranial pressures or endothelial injury. In this article, we will review the clinical, typical, and atypical radiological features of PRES, as well as the most common theories behind the pathophysiology of PRES. Additionally, we will discuss some of the treatment strategies for PRES related to the underlying disease state., (Copyright © 2020 Anderson, Patel, Sheikh-Bahaei, Liu, Rajamohan, Shiroishi, Kim, Go, Lerner and Acharya.)

Technologic advances have resulted in the expansion of web-based conferencing and education. While historically video-conferencing has been used for didactic educational sessions, we present its novel use in virtual radiology read-outs in the face of the COVID-19 pandemic. Knowledge of key aspects of set-up, implementation, and possible pitfalls of video-conferencing technology in the application of virtual read-outs can help to improve the educational experience of radiology trainees and promote potential future distance learning and collaboration., (Copyright © 2020 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)

Diagnosis of Posterior Reversible Encephalopathy Syndrome (PRES) in some circumstances can be challenging and structural imaging may not be sufficient to distinguish it from other differential diagnostic considerations. Advanced imaging techniques, such as MR spectroscopy or positron emission tomography (PET) can provide additional information to determine the diagnosis. Other techniques, such as susceptibility weighted imaging (SWI) improves detection of hemorrhage which has prognostic role. CT or MR Perfusion as well as Single-Photon Emission Computed Tomography (SPECT) are more useful to understand the underlying vasculopathic changes in PRES and may answer some of the unresolved controversies in pathophysiology of this complex disease. In this review we summarized the findings of previous studies using these advanced methods and their utilities in diagnosis or prognosis of PRES., (Copyright © 2020 Sheikh-Bahaei, Acharya, Rajamohan and Kim.)

Background: Cystic sellar masses (CSMs) pose diagnostic and therapeutic challenges associated with subtotal cyst wall resection, cerebrospinal fluid (CSF) leak repair, and disease recurrence. Current magnetic resonance imaging (MRI) interpretation often cannot reliably differentiate CSMs, mandating adaptable intraoperative strategies. We reviewed our diagnostic and therapeutic experience after endoscopic endonasal approaches (EEAs) for CSMs., Methods: A retrospective record review of patients with CSM managed via EEA at the University of Southern California from 2011 to 2018 was conducted. Patient demographics, preoperative characteristics, surgical details, pathologic findings, and postoperative outcomes were assessed., Results: Analysis included 47 patients (mean age, 43.2 years); of these, 78.7% were women. Preoperative symptoms included headache (76.6%) and vision loss (42.6%). Histologically verified sellar pathology included 27 Rathke cleft cysts (RCCs) (57.4%), 17 cystic pituitary adenomas (CPAs) (36.2%), 2 arachnoid cysts (4.3%), and 1 xanthogranuloma (2.1%). Twelve patients (70.6%) with CPAs underwent complete resection and 5 (29.4%) underwent subtotal resection. All 27 patients with RCC and 2 patients with arachnoid cyst underwent complete fenestration and drainage. One xanthogranuloma was completely resected. There were 14 intraoperative (29.8%) and 4 postoperative CSF leaks (8.5%). Headaches, vision, and endocrinopathy improved in 69.2%, 80.0%, and 33.3% of patients with CPA and 73.9%, 71.4%, and 40.9% of patients with RCC, respectively. There were 2 RCC recurrences and 1 CPA recurrence over the follow-up period., Conclusions: Surgeons must prepare for versatile management strategies of CSMs based on pretest probability associated with MRI and intraoperative findings. Outcomes after EEA for CSMs show low complication profiles and excellent rates of headache and visual improvement, albeit lower rates of endocrine normalization., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: The pedicled temporoparietal fascial flap (TPFF) with a direct superficial temporal (STA) artery to middle cerebral artery (MCA) bypass is a novel combined revascularization approach for moyamoya angiopathy (MMA). With this case series, we aim to report the initial experience with pedicled TPFF combined revascularization for MMA treatment., Methods: Data from 14 consecutive patients undergoing pedicled TPFF combined revascularization for MMA between May 2016 and December 2018 were retrospectively reviewed. Patients admitted with acute ischemia or a modified Rankin Scale (mRS) score >3 were considered high risk., Results: Mean ± standard deviation age on surgery was 41.9 ± 15.4 years. Three of 14 patients (21.4%) presented with an mRS score >3. Nine of 14 patients (64.3%) presented with ischemic stroke, 4 of whom (44.4%) had acute ischemia. Direct anastomosis patency was confirmed in all cases postoperatively. Mean hospitalization time was 13 ± 9.3 days and mean follow-up time was 14.1 ± 9.3 months. From admission to follow-up, neurologic status improved in 8 patients (57.1%) and stabilized in 6 patients (42.9%). Overall, 11/14 patients (78.6%) achieved good functional outcome (mRS score ≤2). All patients achieved some radiographic collateral development, with 5 (71.5%) graded as Matsushima A and B. Three patients developed new radiographic ischemia and 3 experienced wound complications, all in the high-risk group., Conclusions: The TPFF combined approach is a viable strategy for revascularization in MMA. This technique may be suboptimal in patients presenting with acute ischemia and/or mRS score >3., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Objective: Middle cerebral artery (MCA) aneurysms have continued to be primarily managed microsurgically. In cases of complex MCA aneurysms, revascularization could facilitate effective aneurysm treatment. The MCA candelabra provides excellent candidates for in situ side-to-side bypass. In the present case series, we have described applications of MCA in situ side-to-side bypass for the management of complex MCA aneurysms, along with a review of the pertinent data., Methods: A retrospective review of a prospectively maintained neurosurgical patient database was performed to identify all patients treated with MCA side-to-side in situ bypass. Six consecutive patients were identified and included in the present series, representing a single-surgeon experience from February 2016 to November 2018., Results: Of the 6 complex MCA aneurysms, all were unruptured, and one half had been treated via a minipterional approach that also allowed for simultaneous anterior communicating artery aneurysm clipping in 1 case. The median temporary occlusion time for anastomosis was 33 minutes (interquartile range [IQR], 30.3-35 minutes). Bypass patency was confirmed in all cases both intraoperatively and postoperatively. The median hospitalization time was 4.5 days (IQR, 2-8 days). The median follow-up period was 5.5 months (IQR, 2.8-22.3 months). All patients had achieved excellent or good (≤1) modified Rankin scale scores at discharge and during the follow-up period. No mortalities occurred, and no technical, bypass-related, or ischemic morbidities had developed., Conclusions: Our experience with MCA side-to-side in situ bypass has demonstrated its safety and utility in complex MCA aneurysm management. The favorable anatomy of the MCA branches allows for minimally invasive revascularization and clipping that can potentially reduce the hospitalization time and incidence of perioperative morbidity., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Headaches are exceedingly common, but most individuals who seek medical attention with headache will not have a serious underlying etiology such as a brain tumor. Brain tumors are uncommon; however, many patients with brain tumors do suffer from headaches. Generally these headaches are accompanied by other neurologic signs and symptoms. A careful clinical assessment for red flags should be undertaken when considering further work-up with neuroimaging to exclude a serious underlying condition., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Large broad-based basilar artery (BA) apex aneurysms involving multiple arterial origins are complex lesions commonly not amenable to direct clipping or endovascular management. BA proximal (Hunterian) occlusion with extracranial-to-intracranial bypass is a supported strategy if 1 or both posterior communicating arteries are small. Hunterian ligation risks sudden aneurysm thrombosis and thromboembolism in the perforator-rich BA apex. There currently exist no guidelines for antiplatelet and anticoagulant therapy after Hunterian ligation for complex BA apex aneurysm treatment. We present a literature review and an illustrative case of an 18-year-old man who presented with progressive headaches and was found to have a large unruptured BA apex aneurysm involving the origins of the bilateral superior cerebellar and posterior cerebral arteries. Given the small posterior communicating arteries and complexity of the aneurysm, proximal BA occlusion with unilateral superficial temporal artery-to-superior cerebellar artery bypass was recommended. Despite antiplatelet treatment with acetylsalicylic acid before and after operation, the patient experienced acute ischemia of the brainstem and cerebellum and an embolic left temporal lobe infarct. The patient received dual antiplatelet therapy starting on postoperative day 6, after which he experienced no new infarcts and made a significant neurologic recovery. The current evidence suggests that proximal BA occlusion in complex BA apex aneurysm cases is thrombogenic and can be especially dangerous if thrombosis occurs suddenly in aneurysms without pre-existing intraluminal thrombus. Dual antiplatelet therapy during the first postoperative week presents a possible strategy for reducing the risk of ischemia due to sudden aneurysm thrombosis., (Copyright © 2018 Elsevier Inc. All rights reserved.)

OBJECTIVETumor and edema volume changes of brain metastases after stereotactic radiosurgery (SRS) and ipilimumab are not well described, and there is concern regarding the safety of combination treatment. The authors evaluated tumor, edema, and adverse radiation-induced changes after SRS with and without ipilimumab and identified associated risk factors.METHODSThis single-institution retrospective study included 72 patients with melanoma brain metastases treated consecutively with upfront SRS from 2006 to 2015. Concurrent ipilimumab was defined as ipilimumab treatment within 4 weeks of SRS. At baseline and during each follow-up, tumor and edema were measured in 3 orthogonal planes. The (length × width × height/2) formula was used to estimate tumor and edema volumes and was validated in the present study for estimation of edema volume. Tumor and edema volume changes from baseline were compared using the Kruskal-Wallis test. Local failure, lesion hemorrhage, and treatment-related imaging changes (TRICs) were analyzed with the Cox proportional hazards model.RESULTSOf 310 analyzed lesions, 91 were not treated with ipilimumab, 59 were treated with concurrent ipilimumab, and 160 were treated with nonconcurrent ipilimumab. Of 106 randomly selected lesions with measurable peritumoral edema, the mean edema volume by manual contouring was 7.45 cm3 and the mean volume by (length × width × height)/2 formula estimation was 7.79 cm3 with R2 = 0.99 and slope of 1.08 on line of best fit. At 6 months after SRS, the ipilimumab groups had greater tumor (p = 0.001) and edema (p = 0.005) volume reduction than the control group. The concurrent ipilimumab group had the highest rate of lesion response and lowest rate of lesion progression (p = 0.002). Within the concurrent ipilimumab group, SRS dose ≥ 20 Gy was associated with significantly greater median tumor volume reduction at 3 months (p = 0.01) and 6 months (p = 0.02). The concurrent ipilimumab group also had the highest rate of lesion hemorrhage (p = 0.01). Any ipilimumab was associated with higher incidence of symptomatic TRICs (p = 0.005). The overall incidence of pathologically confirmed radiation necrosis (RN) was 2%. In multivariate analysis, tumor and edema response at 3 months were the strongest predictors of local failure (HR 0.131 and HR 0.125) and lesion hemorrhage (HR 0.225 and HR 0.262). Tumor and edema response at 1.5 months were the strongest predictors of TRICs (HR 0.144 and HR 0.297).CONCLUSIONSThe addition of ipilimumab improved tumor and edema volume reduction but was associated with a higher incidence of lesion hemorrhage and symptomatic TRICs. There may be a radiation dose-response relationship between SRS and ipilimumab when administered concurrently. Early tumor and edema response were excellent predictors of subsequent local failure, lesion hemorrhage, and TRICs. The incidence of pathologically proven RN was low, supporting the relative safety of ipilimumab in radiosurgery treatment.

Background: Stereotactic radiosurgery (SRS) alone is an increasingly accepted treatment for brain metastases, but it requires adherence to frequently scheduled follow-up neuroimaging because of the risk of distant brain metastasis. The effect of disparities in access to follow-up care on outcomes after SRS alone is unknown., Methods: This retrospective study included 153 brain metastasis patients treated consecutively with SRS alone from 2010 through 2016 at an academic medical center and a safety-net hospital (SNH) located in Los Angeles, California. Outcomes included neurologic symptoms, hospitalization, steroid use and dependency, salvage SRS, salvage whole-brain radiotherapy, salvage neurosurgery, and overall survival., Results: Ninety-three of the 153 patients were private hospital (PH) patients, and 60 were SNH patients. The median follow-up time was 7.7 months. SNH patients received fewer follow-up neuroimaging studies (1.5 vs 3; P = .008). In a multivariate analysis, the SNH setting was a significant risk factor for salvage neurosurgery (hazard ratio [HR], 13.65; P < .001), neurologic symptoms (HR, 3.74; P = .002), and hospitalization due to brain metastases (HR, 6.25; P < .001). More clinical visits were protective against hospitalizations due to brain metastases (HR, 0.75; P = .002), whereas more neuroimaging studies were protective against death (HR, 0.65; P < .001)., Conclusions: SNH patients with brain metastases treated with SRS alone had fewer follow-up neuroimaging studies and were at higher risk for neurologic symptoms, hospitalization for brain metastases, and salvage neurosurgery in comparison with PH patients. Clinicians should consider the practice setting and patient access to follow-up care when they are deciding on the optimal strategy for the treatment of brain metastases. Cancer 2018;124:167-75. © 2017 American Cancer Society., (© 2017 American Cancer Society.)

Intramedullary spinal cord abscesses are rarely encountered in modern neurosurgical practice. Select patients are at high risk for developing an intramedullary spinal cord abscess, which can result in acute neurologic deficits. Patients with failed conservative management may benefit from early surgical intervention; however, the evidence is limited by level 3 studies. In this case presentation, the patient failed conservative management for a cervical intramedullary spinal cord abscess and developed acute neurologic deficits. The decision was made to perform an urgent cervical laminectomy and drainage to avoid any further decline that may have occurred with continued conservative management. Increased awareness of intramedullary spinal cord abscess is warranted for its clinical suspicion and emergent treatment in select circumstances., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Central neurocytomas comprise nearly half of adult intraventricular neoplasms. The median age of onset is 34 years. It is typically a low-grade neoplasm (World Health Organization grade II), although some cases of malignant neurocytomas have been described. We present a rare case of an atypical central neurocytoma with craniospinal dissemination, including both imaging and pathologic findings., (Published by Elsevier Inc.)

This article provides an overview of the neuroimaging literature focused on preoperative prediction of meningioma consistency. A validated, noninvasive neuroimaging method to predict tumor consistency can provide valuable information regarding neurosurgical planning and patient counseling. Most of the neuroimaging literature indicates conventional MRI using T2-weighted imaging may be helpful to predict meningioma consistency; however, further rigorous validation is necessary. Much less is known about advanced MRI techniques, such as diffusion MRI, MR elastography (MRE), and MR spectroscopy. Of these methods, MRE and diffusion tensor imaging appear particularly promising., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Background: Adjuvant stereotactic radiosurgery (SRS) alone after surgical resection is increasingly being used to provide excellent local control while avoiding the side effects of whole brain radiation therapy (WBRT). We report our ten year experience using this treatment scheme., Purpose/objectives: To determine the rates and any correlates of local control, distant brain failure, and overall survival using SRS alone to the resection cavity., Materials/methods: We performed a retrospective analysis of 509 patients with brain metastasis who underwent Gamma Knife SRS at our institution between 2003 and 2013. Of this group 85 patients were identified that had resection of the metastasis and subsequent SRS to the cavity. Mean dose to the resection cavity was 17.3 Gy (range 14-20) to an average volume of 12cc (range 0.3-83cc). Multiple patient, tumor, and treatment specific factors were collected for analysis (see Table 1). Vital statistics were provided by our institution's tumor registry. The primary endpoint of our analyses was recurrence free survival (RFS); defined as the duration in time between the date of SRS and any local or distant brain tumor recurrence., Results: With a median follow up of 16.4 months, the overall local and distant brain failure at 12 months was 13% (95%CI 5%-21%) and 51% (95%CI 37%-64%) respectively. RPA was class 1 (5%), 2 (75%), and 3 (20%). The median overall survival (OS) was 20 months. The median RFS was 24 months with radiosensitive tumors: non small cell lung cancer (n=12), breast (n=16), gastrointestinal (n=7), small cell lung cancer (n=1), and other (n=9) compared to 5.6 months (p=0.006) in radioresistant tumors: melanoma (n=33), sarcoma (n=1), and renal cell carcinoma (n=6). Median OS for radioresistant and radiosensitive patients was 12 vs 25 months respectively (p=0.11). Additionally, there was a significant improved survival difference seen amongst those who had a gross total resection (GTR, n=46) compared to a sub total resection (n=39) with median OS of 27 vs 16 months (p=0.020) respectively. Radiographic changes suggestive of radiation necrosis were present in 6 patients, 2 of which were determined histiopathologicaly after surgical intervention. Due to the limited number of local recurrence events (n=10), there was insufficient power to analyze prognostic factors for local recurrence., Conclusions: Our results compare favorably with multiple other institution experiences showing excellent local control with SRS to the resection cavity following resection. Radioresistant histologies were associated with a worse RFS. Patients undergoing GTR had a significantly longer OS than those with STR. At our institution we continue to offer patients SRS to the resection cavity for those with good performance status and limited brain metastases.

Objective: Metastatic disease of the craniovertebral junction (CVJ) can cause pain, cranial nerve deficits, occipitocervical instability, or brainstem/spinal cord compression if left untreated. Many patients with metastasis in this region have a high burden of systemic disease and short life expectancy, making them poor candidates for aggressive surgical resections and fusion procedures. Traditionally, symptom palliation and local disease control in these patients has been achieved through conventional radiation therapy. Stereotactic radiosurgery (SRS) has the advantage of precisely delivering radiation to a target in fewer fractions. To our knowledge, we report the results of the largest series of patients with CVJ metastasis treated with stereotactic radiosurgery., Methods: We performed a retrospective review of 9 consecutive patients with 10 tumors of the CVJ treated with SRS at the Keck Medical Center of the University of Southern California. Two tumors were treated with Gamma Knife, whereas the other 8 received CyberKnife., Results: The median marginal dose was 20 Gy (16-24 Gy) over 1-5 fractions. Point maximal dose to the brainstem or spinal cord ranged between 8 and 18.9 Gy. Median survival was 4 months (1-51 months). Five of six patients presenting with pain had at least partial symptom resolution. No patient went on to require surgical decompression or fusion, and there were no complications directly related to SRS., Conclusions: In well-selected patients, SRS for metastatic lesions of the CVJ has a low risk for complications or treatment failure, while achieving a high rate of palliation of pain symptoms., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Advancements in diffusion-weighted imaging during the past decade have led to the use of diffusion tensor imaging to further characterize the structural integrity of neural tissue and to noninvasively trace neuronal tracts in the brain and spine. This has led to many clinical applications that have aided in surgical planning for brain and spinal cord tumors and has increased the diagnostic potential of magnetic resonance imaging in disorders such as multiple sclerosis, Alzheimer disease, and traumatic brain injury., (Copyright © 2014 Elsevier Inc. All rights reserved.)

The quantitative, multiparametric assessment of brain lesions requires coregistering different parameters derived from MRI sequences. This will be followed by analysis of the voxel values of the ROI within the sequences and calculated parametric maps, and deriving multiparametric models to classify imaging data. There is a need for an intuitive, automated quantitative processing framework that is generalized and adaptable to different clinical and research questions. As such flexible frameworks have not been previously described, we proceeded to construct a quantitative post-processing framework with commonly available software components. Matlab was chosen as the programming/integration environment, and SPM was chosen as the coregistration component. Matlab routines were created to extract and concatenate the coregistration transforms, take the coregistered MRI sequences as inputs to the process, allow specification of the ROI, and store the voxel values to the database for statistical analysis. The functionality of the framework was validated using brain tumor MRI cases. The implementation of this quantitative post-processing framework enables intuitive creation of multiple parameters for each voxel, facilitating near real-time in-depth voxel-wise analysis. Our initial empirical evaluation of the framework is an increased usage of analysis requiring post-processing and increased number of simultaneous research activities by clinicians and researchers with non-technical backgrounds. We show that common software components can be utilized to implement an intuitive real-time quantitative post-processing framework, resulting in improved scalability and increased adoption of post-processing needed to answer important diagnostic questions.

One of the major pitfalls faced by physicians is a basic lack of understanding of the legal aspects of medical malpractice. It is the authors' hope that the brief review of the history of malpractice law provided here affords the radiologist insights that could prove helpful in understanding how one must conduct oneself in a radiology practice. There are several noteworthy points to consider. Vigilance and minimizing errors is always most desirable, but error-free neuroradiology is unattainable. Best medical judgment, although not error free, is at least defensible as noted in the case law discussed here., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Background: Intramedullary abscess of the spinal cord is a rare entity, especially in the setting of an intracardiac shunt, which, to our knowledge, has not been described in the literature. Here we present a case of an intramedullary spinal cord abscess in a patient with a patent foramen ovale., Methods: The article includes a chart review and description of a clinical case presentation., Results: A 59-year-old man was admitted with rapidly progressive quadriparesis. Magnetic resonance imaging of the cervical spine demonstrated a large intramedullary mass extending from the level of C3 to C7. The patient was taken to the operating room for biopsy and surgical evacuation of the mass. Intraoperative pathology was consistent with abscess, and subsequent cultures grew Streptococcus viridans. On further workup, the patient was found to have a patent foramen ovale with right-to-left flow. Postoperatively, the strength improved significantly in all extremities with residual weakness., Conclusion: This is the first published case of an intramedullary spinal cord abscess in the setting of an intracardiac right-to-left shunt. Although intramedullary spinal cord abscess is rare, there are certain predisposing conditions that increase the risk of its occurrence., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Advancements in imaging of the central nervous system have paralleled and propelled neurosurgical practice. These technologic innovations have expanded our understanding of neuroanatomy and neuropathology, helping to refine neurosurgical techniques to be more precise and less invasive. Nanotechnology will play a significant role in the next wave of technology that will continue to improve neurosurgical practice. With specific regard to neuroimaging, nanotechnology has the potential to provide more precise resolution when imaging nervous system malignancies. Nanoparticles may be engineered to noninvasively visualize pathology once found only under a microscope. They will enhance our ability to target new disease processes and thus develop more precise surgical and nonsurgical treatments. This article will discuss the background of nanotechnology's use in imaging of the nervous system, its current status, and future potentials., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Cervical spondylotic myelopathy due to ossification of the posterior longitudinal ligament (OPLL) is a common neurosurgical disease that carries high morbidity. OPLL and other degenerative processes cause narrowing of the central canal, with subsequent spinal cord injury. Repeated minor trauma and vascular aberrations have been purported to underlie cervical spondylotic myelopathy, although the exact pathophysiological mechanism is unclear. Regardless, detection of early axonal damage may allow more timely surgical intervention and prediction of functional outcome. Diffusion tensor (DT) imaging of the cervical spine is a novel technique with improved sensitivity compared with conventional anatomical MR imaging that is currently available on most clinical scanners. This review describes the theoretical basis, application, and analysis of DT imaging as it pertains to neurosurgery. Particular emphasis is placed on OPLL.

Conventional contrast-enhanced MR imaging is the current standard technique for the diagnosis and treatment evaluation of gliomas and other brain neoplasms. However, this method is quite limited in its ability to characterize the complex biology of gliomas and so there is a need to develop more quantitative imaging methods. Perfusion and permeability MR imaging are two such techniques that have shown promise in this regard. This review will highlight the underlying principles, applications, and pitfalls of these evolving advanced MRI methods.

Molecular imaging is a field born out of the happy marriage of molecular biology and radiology. The first installment of this two-part series on molecular imaging demonstrated basic principles for practitioners in the field of the neurosciences. This installment seeks to provide some illustrative examples, insights, and specific applications to the neurosciences. The fields of functional neurosurgery including the treatment of neuropsychiatric disorders, novel treatments and imaging of tumors, neuroregenerative medicine, and nanotechnology in vascular disorders are covered. Finally, we give some parting thoughts on the future of molecular imaging, including advances in the imaging of neurodegenerative disorders., (Published by Elsevier Inc.)

Conventional imaging paradigms rely on the detection of anatomical changes in disease that are preceded by molecular genetic changes that go otherwise undetected. With the advent of molecular imaging, it will be possible to detect these changes prior to the manifestation of disease. Molecular imaging is the amalgamation of molecular biology and imaging technology that was spawned by parallel advances in the two fields. Fundamental to this technique is the ability to directly image biological processes that precede the anatomical changes detected by conventional imaging techniques. The two main strategies for imaging of biologic processes are direct and indirect imaging techniques. Direct techniques use molecules that have specific affinities for targets of interest that can be radiolabeled or otherwise detected on imaging. Indirect imaging uses reporter genes that are coexpressed with therapeutic proteins or other proteins of interest to image vector-transfected cells. Optical imaging and nanotechnology paradigms will also prove to be important additions to the imaging armamentarium. The first installment of this two-part series on molecular imaging seeks to demonstrate basic principles and illustrative examples for the uninitiated neophyte to this field., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Objective: Several different methodologies for proximal occlusion and retrograde suction decompression of large paraclinoid aneurysms have been reported previously. In this article, we describe the novel use of an endovascular embolectomy device (F.A.S.T. funnel catheter; Genesis Medical Interventional, Inc., Redwood City, CA) for temporary internal carotid artery occlusion and suction decompression of an intracranial aneurysm to facilitate surgical clip ligation. The combination of atraumatic occlusion technology and large lumen size makes this technique safer and easier., Clinical Presentation: A 53-year-old woman with progressive headaches underwent computed tomographic angiography, which revealed an unruptured large left paraclinoid aneurysm. Cerebral angiography confirmed the diagnosis. The patient did not tolerate a balloon test occlusion for therapeutic Hunterian internal carotid occlusion. The patient was subsequently taken to the operating room for a craniotomy and clip ligation of the aneurysm., Intervention: A standard left pterional craniotomy was performed with opening of the sylvian fissure and exposure of the left paraclinoid aneurysm. Intraoperative angiography with introduction of a new endovascular embolectomy device was performed. The device was deployed to achieve temporary occlusion of the cervical internal carotid artery, and aspiration through the central lumen allowed for retrograde suction decompression of the aneurysm. Collapse of the aneurysm through this technique permitted visualization of the aneurysmal neck with successful clip ligation., Conclusion: A new endovascular embolectomy device can be used to safely perform suction decompression of large paraclinoid aneurysms to facilitate clip ligation.

The history of the development of cerebral imaging is a complex combination of the forces of innovation at both the individual and industrial levels. Principal paradigms of neuroimaging shifted as a result of technological breakthroughs, beginning with the discovery of x-rays and continuing with the development of computerized imaging to the latest imaging paradigm, nuclear magnetic resonance imaging. We discuss these landmarks in neuroimaging in historical context, with emphasis on the particularly rapid development of imaging technology during the past 30 to 40 years, including the most recent emerging technologies.

Radiosurgery is now the preferred treatment modality for many intracranial disease processes. Although almost 50 years have passed since it was introduced as a tool to treat neurological disease, investigations into its effects on normal tissues of the central nervous system are still ongoing. The need for these continuing studies must be underscored. A fundamental understanding of the brain parenchymal response to radiosurgery would permit development of strategies that would enhance and potentiate the radiosurgical treatment effects on diseased tissue while mitigating injury to normal structures. To date, most studies on the response of the central nervous system to radiosurgery have been performed on brain tissue in the absence of pathological lesions, such as benign tumors or metastases. Although instructive, these investigations fail to emulate the majority of clinical scenarios that involve radiosurgical treatment of specific lesions surrounded by normal brain parenchyma. This article is the first in a two-part series that addresses the brain parenchyma's response to radiosurgery. This first article analyzes the histological, radiographic, and molecular data gathered regarding the brain parenchymal response to radiosurgery and aims to suggest future studies that could enhance our understanding of the topic. The second article in the series begins by discussing strategies for radiosurgical therapeutic enhancement. It concludes by focusing on strategies for mitigation and repair of radiation-induced brain injury.

Primary central nervous system lymphoma (PCNSL) is an aggressive neoplastic process that occurs in both immunocompetent and immunocompromised patients. Over the past 30 years there has been a steady increase in the number of cases in both patient populations. The imaging features for the disease and demographic characteristics within these patient populations vary, and in this article the authors describe the salient features of these two groups.

One of the most pertinent applications of the principle primum non nocere (first do no harm) is in the optimization of neurosurgical procedures for patients with resectable lesions. The gold standard for identifying eloquent areas of the brain to be avoided in resections is direct cortical stimulation and somatosensory evoked potential monitoring, which is itself an invasive, cumbersome and difficult technique for mapping these areas. Functional magnetic resonance imaging shows great promise as a viable noninvasive alternative to invasive mapping as well as significant current clinical utility in cases in which it cannot yet fully supplant cortical stimulation methods. Ongoing work is directed toward overcoming technical limitations, improved mapping of complex functions such as language and memory, and mapping of white matter tracts.

The pituitary is part of a chain of enormous biologic amplification, which is regulated by a small amount of releasing factors in the portal blood from the hypothalamus. The pituitary is a master gland that regulates a number of hormones. A subtle abnormality in the pituitary can cause significant changes in body metabolism. Because the pituitary glands are small structures, high-resolution imaging techniques are required to satisfactorily evaluate the gland. It is imperative for the radiologist to be familiar with the anatomy, physiology, and pathology of the pituitary gland, which provides a solid foundation for accurate interpretation of the imaging studies of the pituitary gland.

The imaging of head trauma has been one of the fundamental cornerstones of neuroradiology. As the practice of neuroimaging has matured, great strides have been made in the diagnostic as well as prognostic armamentarium available to physicians. Given the vast diversity of trauma mechanisms and clinical pathways, new advanced imaging technologies have had a lasting impact on the detection, description, and depiction of head trauma. Furthermore, these new tools are allowing the imaging specialist to function not only as an interpreter of what is seen but as a 21st century radiographic oracle. We present a comprehensive review of the imaging findings of sequlae of traumatic brain injury and the growing correlation of new neuroimaging techniques and neurotraumatic outcomes.

Though advances in MRI will undoubtedly increase its use, particularly in the subacute period, CT will likely continue its primary role in the management of these injuries in the foreseeable future. The spectrum of imaging features of cranial gunshot injuries is vast, because they encompass all of the findings encountered in closed head injury in addition to the wide variety of problems associated with penetration. Thus, only a brief summary of the many varied aspects of this complex problem is presented here as a review of the more salient issues.

The trigeminal nerve is the largest of the cranial nerves, serving as a major conduit for sensory information from the head and neck and primarily providing motor innervation to the muscles of mastication. An understanding of the pathologic processes that may involve this nerve requires a detailed knowledge of its origin within the brain stem as well as its course intracranially. This article describes the neuroanatomy of the nerve and divides it into its various segments to provide a differential diagnosis of common and some uncommon pathologic processes.

The diagnosis and treatment of central nervous system fungal infections typically pose problems for the clinician. With an increased incidence of fungal infections in immunocompromised patients, neuroradiologic imaging has become essential in determining complications and outcomes. This article provides a summary of the more common organisms encountered in fungal infections of the central nervous system and the imaging features primarily seen with CT and MR imaging.

Neurocysticercosis produces a variety of neurologic syndromes resulting from the cysticerci infestation of the central nervous system by the larvae of Taenia solium. Because of increased immigration to the United States from endemic areas, the incidence of neurocysticercosis has increased, especially in California, Texas, Arizona, and other southwestern states. Neuroimaging studies play a significant role in the diagnosis and management of patients with neurocysticercosis.

We examined the relation of invasive pneumococcal disease to season, atmospheric conditions, and the rate of respiratory virus isolation in a community-wide surveillance program in Houston. Among adults, the number of cases of pneumococcal bacteremia peaked in midwinter and declined strikingly in midsummer, indicating a high degree of inverse correlation with the ambient temperature. We detected significant correlations between the occurrence of pneumococcal disease and the isolation of respiratory syncytial virus (P < .001), influenza virus (P < .001), and all viruses except influenza virus (P < .001), as well as with air pollution, as measured by SO2 levels (P < .001). In contrast, the rate of invasive pneumococcal disease among infants and children was relatively more sustained from October through May, with a notable decrease in summer months; the incidence of pneumococcal disease was therefore less strongly correlated with cold weather and less closely associated with the isolation of respiratory syncitial virus or influenza virus. However, pneumococcal disease among infants and children was associated with isolation of these viruses after a 4-week lag period as well as with isolation of adenovirus and ragweed pollen counts. The finding, with regard to children, that correlations tended to be stronger for events that occurred 1 month previously than for those that occurred contemporaneously is consistent with the concept that viral or allergic events predispose to otitis media with effusion, which becomes suppurative and leads to pneumococcal bacteremia or meningitis. For adults, a more immediate predisposition to pneumococcal pneumonia and bacteremia because of viral infection or air pollution was suggested.

A brief overview of the imaging findings in craniocerebral missile injury is presented here. CT scanning has established itself as the primary imaging modality for the complex injuries seen in CMI as well as its acute and delayed complications. Plain x-ray, angiography, and magnetic resonance imaging have more limited but sometimes important roles in the management of these injuries. With regard to outcome prediction, imaging has also proved to be of some, albeit limited, usefulness, primarily as adjuncts to clinical criteria such as the GCS. Future research with CT as well as magnetic resonance imaging will likely expand the clinical role of these modalities, particularly in the realm of outcome analysis.