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To summarize the current evidence on the diagnostic evaluation of cranial cerebrospinal fluid (CSF) leaks and encephaloceles, including laboratory testing and imaging studies.The most sensitive and specific laboratory tests for CSF leak diagnosis are beta-2-transferrin and beta trace protein assays, the former more commonly used because of availability. Imaging studies used for localization of the leak site include high resolution computed tomography (HRCT) and magnetic resonance cisternography (MRC), often used in combination. Intrathecal contrast administration is reserved for complex cases with prior equivocal test results or for patients with multiple skull base defects to localize the leak site.Diagnosis of CSF leaks and encephaloceles is aimed at both confirming the leak and localizing the leak site. Future advancements in testing techniques may shorten the diagnostic process, limit the need for invasive testing, and improve the safety of such testing in indicated cases.

Objective: Examine the effects of a multi-disciplinary skull base conference (MDSBC) on the management of patients seen for skull base pathology in a neurotology clinic. Methods: Retrospective case review of patients who were seen in a neurotology clinic at a tertiary academic medical center for pathology of the lateral skull base and were discussed at an MDSBC between July 2019 and February 2020. Patient characteristics, nature of the skull base pathology, and pre- and post-MDSBC plan of care was categorized. Results: A total of 82 patients with pathology of the lateral skull base were discussed at a MDSBC during an 8-month study period. About 54 (65.9%) had a mass in the internal auditory canal and/or cerebellopontine angle while 28 (34.1%) had other pathology of the lateral skull base. Forty-nine (59.8%) were new patients and 33 (40.2%) were established. The management plan changed in 11 (13.4%, 7.4-22.6 95% CI) patients as a result of the skull base conference discussion. The planned management changed from some form of treatment to observation in 4 patients, and changed from observation to some form of treatment in 4 patients. For 3 patients who underwent surgery, the planned approach was altered. Conclusions: For a significant proportion of patients with pathology of the lateral skull base, the management plan changed as a result of discussion at an MDSBC. Although participants of a MDSBC would agree of its importance, it is unclear how an MDSBC affects patient outcomes.

Objective: The aim of this study was to determine the incidence of cochlear fibrosis after vestibular schwannoma (VS) resection via middle cranial fossa (MCF) approach. Design: A retrospective case review was conducted. Setting: The review was conducted in a tertiary care academic medical center. Participants: Patients who (1) underwent resection of VS via MCF approach between 2013 and 2018, (2) had complete pre- and post-audiometric testing, and (3) had clinical follow-up with magnetic resonance imaging (MRI) for at least 1 year after surgery were included. Main Outcome Measure(s): The main outcome of this study was cochlear fibrosis as assessed by MRI 1 year after surgery. Results: Fifty-one patients underwent VS resection via MCF technique during the study period. Of 31 patients with AAO-HNS class A or B preoperative hearing ability, 18 (58.0%) maintained class A, B, or C hearing postoperatively. Of 16 patients who lost hearing and had MRI 1 year after surgery, 11 (61.1%) had MRI evidence of fibrosis in at least some portion of the labyrinth and 4 (22.2%) showed evidence of cochlear fibrosis. Of 16 patients with preserved hearing and MRI 1 year after surgery, 4 (25%) had fibrosis in some portion of the labyrinth, with no fibrosis in the cochlea. Conclusions: In patients who lose hearing during VS resection with the MCF approach, there is usually MRI evidence of fibrosis in the labyrinth 1 year after surgery. However, there is also, but less commonly, fibrosis involving the cochlea. It is unclear if this will affect the ability to insert a cochlear implant electrode array.

A 54-year-old female presented with multiple episodes of emesis, intractable headaches, worsening balance, and slowly progressive right facial weakness. Imaging demonstrated a 3-cm mass in the left internal capsule and corona radiata region with associated edema, mass effect, and midline shift concerning for high-grade glioma, lymphoma, or brain metastasis. Stereotactic biopsy of the mass was consistent with amyloid deposition. Systemic workup for amyloidosis was negative, and the mass was thought to represent a focal tumor-like deposit of amyloid, also referred to as “amyloidoma.” In the absence of systemic disease, therapy, which can include surgery or radiotherapy, can be directed at the local process. The location of the patient's lesion was not amenable to resection; therefore, she was treated with fractionated radiotherapy of 30.6 Gy at 1.8 Gy per fraction. Serial brain MRI demonstrated stability 18 months out from therapy. To the authors' knowledge, this is the first documented case of focal fractionated radiotherapy for CNS amyloidoma. The authors concluded that radiotherapy can prevent further progression of amyloidomas in anatomical locations that prohibit resection.

To demonstrate the clinical utility, sensitivity, and specificity of standard magnetic resonance imaging (MRI) sequences in differentiating temporal bone cerebrospinal fluid leaks from all other middle ear effusions.Retrospective imaging review.Academic medical center.Patients with cerebrospinal fluid leaks or other middle ear effusions who also underwent MRI.Patients were assigned to cerebrospinal fluid leak and other effusion cohorts based on clinical course, findings at surgery/myringotomy, and beta-2 transferrin fluid analysis. Reviewers blinded to the clinical outcome examined T1-weighted, T2-weighted, diffusion-weighted, fluid-attenuated inversion recovery (FLAIR), and 3-dimensional (3D) acquired T2-weighted MRI sequences. For each sequence, fluid imaged in the temporal bone was graded as either similar or dissimilar in signal intensity to cerebrospinal fluid in the adjacent subarachnoid space. Signal similarity was interpreted as being diagnostic of a leak. Test characteristics in predicting the presence of a leak were calculated for each series.Eighty patients met criteria (41 leaks, 39 other effusions). The 3D T2 series was 76% sensitive and 100% specific in diagnosing a leak, and FLAIR was 44% sensitive and 100% specific. The T1-weighted (73% sensitive, 69% specific), T2-weighted (98% sensitive, 5.1% specific), and diffusion-weighted (63% sensitive, 66% specific) series were less useful.MRI, with attention to 3D T2 and FLAIR series, is a noninvasive and highly specific test for diagnosing cerebrospinal fluid leak in the setting of an indeterminate middle ear effusion.

Neoplasia of the spinal cord, including both primary and metastatic tumors, is relatively rare, representing 4%-10% of all central nervous system tumors, and can present a diagnostic challenge to the radiologist. More than 90% of primary spinal cord neoplasms are derived from the glial cell lineage, including the 2 most common tumors ependymoma and astrocytoma. However, less common spinal cord tumors, including metastatic disease, as well as nonneoplastic and paraneoplastic processes should be considered in the diagnosis of intramedullary spinal cord lesions.

Head trauma is a common indication for neuroimaging in the emergency room. CT is the modality of first choice, as it is quick, safe, and effective in evaluating for life-threatening intracranial hemorrhage and mass effect. CT is also best for evaluating for skull fractures, which may alter management and lead to further imaging studies. MRI is reserved for selected patients, particularly when the clinical exam does not match the CT imaging findings, such as in diffuse axonal injury. Emergency room physicians and radiologists, particularly those in training, would benefit from a consistent approach and search pattern for evaluating head trauma. We offer a comprehensive "outside-to-inside" approach to head trauma imaging, discussing not only common findings but also subtle "should not miss" findings and their clinical correlation.