Explore the vast range of titles available.

Imaging plays a critical role in the evaluation of a number of facial nerve disorders. The facial nerve has a complex anatomical course; thus, a thorough understanding of the course of the facial nerve is essential to localize the sites of pathology. Facial nerve dysfunction can occur from a variety of causes, which can often be identified on imaging. Computed tomography and magnetic resonance imaging are helpful for identifying bony facial canal and soft tissue abnormalities, respectively. Ultrasound of the facial nerve has been used to predict functional outcomes in patients with Bell’s palsy. More recently, diffusion tensor tractography has appeared as a new modality which allows three-dimensional display of facial nerve fibers.

Background Eye–hand coordination (EHC) is a sophisticated act that requires interconnected processes governing synchronization of ocular and manual motor systems. Precise, timely and skillful movements such as reaching for and grasping small objects depend on the acquisition of high-quality visual information about the environment and simultaneous eye and hand control. Multiple areas in the brainstem and cerebellum, as well as some frontal and parietal structures, have critical roles in the control of eye movements and their coordination with the head. Although both cortex and cerebellum contribute critical elements to normal eye-hand function, differences in these contributions suggest that there may be separable deficits following injury. Method As a preliminary assessment for this perspective, we compared eye and hand-movement control in a patient with cortical stroke relative to a patient with cerebellar stroke. Result We found the onset of eye and hand movements to be temporally decoupled, with significant decoupling variance in the patient with cerebellar stroke. In contrast, the patient with cortical stroke displayed increased hand spatial errors and less significant temporal decoupling variance. Increased decoupling variance in the patient with cerebellar stroke was primarily due to unstable timing of rapid eye movements, saccades. Conclusion These findings highlight a perspective in which facets of eye-hand dyscoordination are dependent on lesion location and may or may not cooperate to varying degrees. Broadly speaking, the results corroborate the general notion that the cerebellum is instrumental to the process of temporal prediction for eye and hand movements, while the cortex is instrumental to the process of spatial prediction, both of which are critical aspects of functional movement control.

Mutant isocitrate dehydrogenase 1 ( IDH1 ) is common in gliomas, and produces D-2-hydroxyglutarate (D-2-HG). The full effects of IDH1 mutations on glioma biology and tumor microenvironment are unknown. We analyzed a discovery cohort of 169 World Health Organization (WHO) grade II–IV gliomas, followed by a validation cohort of 148 cases, for IDH1 mutations, intratumoral microthrombi, and venous thromboemboli (VTE). 430 gliomas from The Cancer Genome Atlas were analyzed for mRNAs associated with coagulation, and 95 gliomas in a tissue microarray were assessed for tissue factor (TF) protein. In vitro and in vivo assays evaluated platelet aggregation and clotting time in the presence of mutant IDH1 or D-2-HG. VTE occurred in 26–30 % of patients with wild-type IDH1 gliomas, but not in patients with mutant IDH1 gliomas (0 %). IDH1 mutation status was the most powerful predictive marker for VTE, independent of variables such as GBM diagnosis and prolonged hospital stay. Microthrombi were far less common within mutant IDH1 gliomas regardless of WHO grade (85–90 % in wild-type versus 2–6 % in mutant), and were an independent predictor of IDH1 wild-type status. Among all 35 coagulation-associated genes, F3 mRNA, encoding TF, showed the strongest inverse relationship with IDH1 mutations. Mutant IDH1 gliomas had F3 gene promoter hypermethylation, with lower TF protein expression. D-2-HG rapidly inhibited platelet aggregation and blood clotting via a novel calcium-dependent, methylation-independent mechanism. Mutant IDH1 glioma engraftment in mice significantly prolonged bleeding time. Our data suggest that mutant IDH1 has potent antithrombotic activity within gliomas and throughout the peripheral circulation. These findings have implications for the pathologic evaluation of gliomas, the effect of altered isocitrate metabolism on tumor microenvironment, and risk assessment of glioma patients for VTE.

MR imaging features of mitochondrial encephalomyopathies, lactic acidosis, and stroke-like episodes, Kearns-Sayre/Pearson syndrome have been described in the literature. We describe extensive white matter changes with abnormal signal intensity lesions involving the deep gray nuclei and myelinated white matter tracts in an 18-year-old female with a large-scale 7.4 kb mitochondrial DNA deletion and a atypical presentation of Kearns-Sayre syndrome. Restricted diffusion due to status spongiosus at the involved sites is also discussed.

Abstract INTRODUCTION: With improving MRI techniques, physicians can better visualize neurovascular compression (NVC) of the trigeminal nerve, as well as proximal and distal nerve atrophy, nerve distortion, and demyelinating plaques. This study aimed to determine the interrater reliability of these different anatomical variables, as well as the accuracy in predicting the side of trigeminal neuralgia (TN) for 2 neuroradiologists. METHODS: High-resolution MRI sequences including T1-Gadolinium and constructive interference in steady state (CISS) sequences were reviewed in 43 patients, with symptomatic TN in 44 nerves, who subsequently underwent Gamma Knife radiosurgery. Thirteen patients had multiple sclerosis (MS)-associated TN. Two neuroradiologists (NR1, NR2), blinded to the side of TN, assessed for the presence or absence of NVC, proximal or distal atrophy, distorted nerve course, as well as predicted the side of TN. RESULTS: The presence of ipsilateral NVC was reported in 79.5% (NR1) and 70.5% (NR2) of nerves, proximal nerve atrophy in 36.4% (NR1) and 40.9% (NR2), distal nerve atrophy in 20.5% (NR1) and 9.1% (NR2), and nerve distortion in 56.8% (NR1) and 38.6% (NR2). Moderate interrater reliability was seen for the assessment of NVC (κ = 0.52, P < .001), while there was only fair reliability for proximal and distal nerve atrophy and nerve distortion (κ = 0.14-0.24, P > .05). MS patients were less likely to have ipsilateral NVC. Sensitivity and specificity of predicting the side of TN was 75.6% and 58.0% for NR1 and 61.4% and 58.2% for NR2, respectively. Interrater reliability on predicting the side of TN was also moderate (κ = 0.42, P < .001). CONCLUSION: Despite improving MRI, the accuracy of predicting the side of TN is limited with moderate interrater reliability. Newer MRI techniques assessing the trigeminal nerve pathway are needed to improve diagnostic accuracy and to better understand the underlying etiology of TN.

In conventional follow-up MRI, a new ring-shaped contrast enhancement can arise at the site of the highest delivered dose as indication of blood-brain barrier disruption. [...]interpretation of findings on structural MRI - changing patterns of contrast enhancement and alteration of signal intensity on T2-/FLAIR-weighted images - is markedly limited, making differentiation of local tumor recurrence from radiation-induced changes difficult. Hypoxia or hypoglycemia - occurring in rapidly growing tumors - increases the expression of VEGF, which is not only a potent angiogenic factor but also a potent permeability factor. [...]dynamic susceptibility contrast T2· magnetic resonance perfusion of highly proliferative neoplasms characteristically demonstrates increased relative cerebral blood volume with associated rapid wash-in and progressive washout kinetics. Postulated hypotheses include increased protein synthesis by proliferative cells, active carrier-mediated transport across the tumor cell membrane, disruption of the blood-brain barrier and high vascular density in neoplastic tissue. 11C-MET and O-(2-18F-Fluoroethyl)L-Tyrosine have reported sensitivity values in the range of 78% and specificity values in the range of 100% among patients after stereotactic radiosurgery. [...]amino acid PET allows for sensitive monitoring of treatment response, early detection of tumor recurrence and improved differentiation of tumor recurrence (ie, high MET uptake) from radiation change (ie, uptake similar to contralateral cortex). [...]differentiation between radiation-induced lesions and tumor recurrence after focused high-dose radiotherapy of brain metastases is challenging.

Background Previous studies suggest that semicircular canal dehiscences (SCDs) have a developmental origin. Objective We hypothesized that if SCDs originate during development, incidence of radiographic SCDs in young children will be higher than in adults. Materials and methods Thirty-four temporal bone HRCTs of children younger than 2 years and 40 temporal bone HRCTs of patients older than 18 years were reformatted and re-evaluated for presence of SCD or canal thinning. Results were compared with indications for HRCT and clinical information. Results SCDs were detected in 27.3% of children younger than 2 years of age (superior, 13.8%; posterior, 20%) and in 3% of adults ( P   <  0.004). Of children with one radiographic dehiscence, 55.6% had multiple and 44% had bilateral SCDs on HRCT. No lateral canal SCDs were present. Thinning of bone overlying the semicircular canals was found in 44% of children younger than 2 years and 2.5% of adults ( P  < 0.0001). Conclusion SCDs are more common on HRCTs of very young children. This supports the hypothesis that SCDs originate from discontinuation of bone deposition/maturation. However, SCDs on imaging do not necessarily correlate with canal dehiscence syndrome and should therefore be interpreted carefully.

Background Magnetic resonance imaging (MRI)-guided laser interstitial thermal therapy (LITT) is a minimally invasive treatment modality that has been gaining traction in neuro-oncology. Laser ablation is a particularly appealing treatment option when eloquent neurologic function at the tumor location precludes conventional surgical excision. Although typically performed under general anesthesia, LITT in awake patients may help monitor and preserve critical neurologic functions. Objective To describe intraoperative workflow and clinical outcomes in patients undergoing awake laser ablation of brain tumors. Methods We present a cohort of six patients with tumors located in eloquent brain areas that were treated with awake LITT and report three different workflow paradigms involving diagnostic or intraoperative MRI. In all cases, we used NeuroBlate® (Monteris Medical, Plymouth, MN) fiberoptic laser probes for stereotactic laser ablation of tumors. The neurologic status of patients was intermittently assessed every few minutes during the ablation. Results The mean preoperative tumor volume that was targeted was 12.09 ± 3.20 cm , and the estimated ablation volume was 12.06 ± 2.75 cm . Performing the procedure in awake patients allowed us close monitoring of neurologic function intraoperatively. There were no surgical complications. The length of stay was one day for all patients except one. Three patients experienced acute or delayed worsening of pre-existing neurologic deficits that responded to corticosteroids. Conclusion We propose that awake LITT is a safe approach when tumors in eloquent brain areas are considered for laser ablation.

Background: While effective for the repair of large skull base defects, the Hadad-Bassagasteguy nasoseptal flap increases operative time and can result in a several-week period of postoperative crusting during re-mucosalization of the denuded nasal septum. Endoscopic transsphenoidal surgery for pituitary adenoma resection is generally not associated with large dural defects and high-flow cerebrospinal fluid (CSF) leaks requiring extensive reconstruction. Here, we present the posterior nasoseptal flap as a novel technique for closure of skull defects following endoscopic resection of pituitary adenomas. This flap is raised in all surgeries during the transnasal exposure using septal mucoperiosteum that would otherwise be discarded during the posterior septectomy performed in binostril approaches. Methods: We present a retrospective, consecutive case series of 43 patients undergoing endoscopic transsphenoidal resection of a pituitary adenoma followed by posterior nasoseptal flap placement and closure. Main outcome measures were extent of resection and postoperative CSF leak. Results: The mean extent of resection was 97.16 ± 1.03%. Radiographic measurement showed flap length to be adequate. While a defect in the diaphragma sellae and CSF leak were identified in 21 patients during surgery, postoperative CSF leak occurred in only one patient. Conclusions: The posterior nasoseptal flap provides adequate coverage of the surgical defect and is nearly always successful in preventing postoperative CSF leak following endoscopic transsphenoidal resection of pituitary adenomas. The flap is raised from mucoperiosteum lining the posterior nasal septum, which is otherwise resected during posterior septectomy. Because the anterior septal cartilage is not denuded, raising such flaps avoids the postoperative morbidity associated with the larger Hadad-Bassagasteguy nasoseptal flap.