Lane, John I.

Objectives: To compare the diagnostic yield of high-resolution volumetric T2-weighted MRI (HRT2-MRI) with high-resolution computed tomography (HRCT) for diagnosis of large vestibular aqueduct (LVA). Study Design: Three board-certified neuroradiologists performed an independent, blinded radiological review for diagnosing LVA with 2:1 age-matched controls on patients with both HRCT and HRT2-MRI imaging. Setting: Tertiary referral center. Patients: All patients between 2002 and 2016 with hearing loss who underwent both HRCT and HRT2-MRI and were diagnosed with LVA on either modality. Main Outcome Measures: Concordance rate for LVA between HRCT and HRT2-MRI. Results: Concordance rate for HRCT and HRT2-MRI for diagnosing LVA was 88% (124/141) when assessing both the midpoint and external aperture diameters. Fifteen ears had LVA on computed tomography (CT), but not on magnetic resonance imaging (MRI); in comparison, two ears had LVA on MRI, but not on CT (p = 0.002). Excellent inter-rater reliability among the three radiologists was demonstrated. Conclusion: Historically, HRCT has been the imaging modality of choice for diagnosing LVA. Although a higher concordance rate of HRT2-MRI was found compared with previous studies utilizing earlier MRI technology, HRCT still detected a larger number of patients with clinically significant hearing loss compared with MRI. Given the high concordance rate and efficacy of both modalities in diagnosing LVA, the ultimate decision of which modality to choose may depend on other patient-specific and clinical factors.

Hypothesis: A new generation 192-slice multi-detector computed tomography (MDCT) clinical scanner provides enhanced image quality and superior electrode localization over conventional MDCT. Background: Currently, accurate and reliable cochlear implant electrode localization using conventional MDCT scanners remains elusive. Methods: Eight fresh-frozen cadaveric temporal bones were implanted with full-length cochlear implant electrodes. Specimens were subsequently scanned with conventional 64-slice and new generation 192-slice MDCT scanners utilizing ultra-high resolution modes. Additionally, all specimens were scanned with micro-CT to provide a reference criterion for electrode position. Images were reconstructed according to routine temporal bone clinical protocols. Three neuroradiologists, blinded to scanner type, reviewed images independently to assess resolution of individual electrodes, scalar localization, and severity of image artifact. Results: Serving as the reference standard, micro-CT identified scalar crossover in one specimen; imaging of all remaining cochleae demonstrated complete scala tympani insertions. The 192-slice MDCT scanner exhibited improved resolution of individual electrodes (p < 0.01), superior scalar localization (p < 0.01), and reduced blooming artifact (p < 0.05), compared with conventional 64-slice MDCT. There was no significant difference between platforms when comparing streak or ring artifact. Conclusion: The new generation 192-slice MDCT scanner offers several notable advantages for cochlear implant imaging compared with conventional MDCT. This technology provides important feedback regarding electrode position and course, which may help in future optimization of surgical technique and electrode design.

Objectives: To report a contemporary review from a single-institution series on Paget's disease of the temporal bone (PDTB). Study Design: Retrospective chart review of patients evaluated from 1998 to 2016. Setting: Quaternary referral center. Patients: Patients with radiographically confirmed PDTB. Main Outcome Measures: Clinical, audiological, and radiological features and management strategies of PDTB. Results: A total of 50 temporal bones in 27 patients (15 men) were diagnosed with PDTB. Symptoms at presentation included hearing loss (n = 23, 85%), headache (n = 18, 67%), dizziness (n = 14, 52%), tinnitus (n = 5, 19%), chronic otitis media (n = 2, 7%), hemifacial spasm without facial paralysis (n = 1, 4%), multiple cranial neuropathies (n = 1, 4%), and neoplastic transformation (n = 1, 4%). Of the 23 ears with audiometric data available for review, 65% exhibited sensorineural hearing loss, and 35% mixed hearing loss. Long-term audiometric follow-up was available on two patients, both of whom demonstrated hearing loss at a rate greater than would be expected for normal aging. Two patients underwent successful cochlear implantation, achieving open-set speech recognition. Radiographic features of temporal bone involvement are reviewed and illustrated. Conclusion: This is the largest single-institution clinical series examining patients with PDTB in the English literature. Variable patterns of temporal bone involvement by Paget's disease are observed leading to a diverse set of clinical symptoms, including slowly progressive hearing loss, tinnitus, compressive cranial neuropathies, and benign or malignant tumorigenesis. Involvement typically begins in the petrous apex and progresses laterally. Otic capsule bone demineralization occurs late in the disease process. Cochlear implantation appears to be an effective management strategy for patients with severe-to-profound hearing loss.

Objective: To describe a unique case of an asymptomatic arteriovenous lesion of the internal auditory canal (IAC) and present the associated imaging findings. Methods: Retrospective case report and review of the literature. Results: A 55-year-old man presented for further evaluation of a left-sided sudden sensorineural hearing loss that occurred 8 years earlier. Careful review of outside serial magnetic resonance (MR) imaging revealed a contralateral, ill-defined right-sided IAC mass with low T2 signal and subtle peripheral enhancement on postcontrast T1-weighted sequencing. The patient had no history of right-sided otologic symptoms. Subsequent dedicated IAC MR imaging confirmed the presence of a space-occupying lesion adjacent to a complexity of vasculature. The presence of prominent flow voids, paucity of avid enhancement on previous studies, and marked signal within the lesion on time-of-flight MR angiography and MR venography was consistent with the diagnosis of a solitary arteriovenous lesion of the IAC. There was no radiological evidence of recent or remote parenchymal or subarachnoid hemorrhage or stroke. Conclusion: We report a novel case of an occult asymptomatic IAC arteriovenous lesion. Vascular anomalies confined to the IAC are rare. To date, there have been only four reports in the literature of IAC arteriovenous lesions and our case is the first to present asymptomatically. A high index of suspicion and dedicated imaging is required to identify and accurately diagnose these lesions to guide appropriate counseling and potential intervention.

Objectives: To describe the clinical presentation, radiological features, and outcome of patients with plasmacytoma of the temporal bone. Methods: Multicenter retrospective case series of all patients diagnosed with plasmacytoma of the temporal bone between 1990 and 2015. Comprehensive literature review of all previously published cases. Results: A total of seven patients (average age, 57.3 yr; 57% women) met inclusion criteria. Three (43%) had a known history of multiple myeloma (MM). The most common symptoms at presentation included otalgia, headache, and dizziness (43%, each). Five (71%) presented with a vascular appearing middle ear mass visible on otoscopy. Four of these patients did not have an established history of MM and were referred with presumptive diagnoses of paraganglioma or endolymphatic sac tumor (ELST). The average maximum tumor diameter was 3.7 cm (median, 3.5 cm; range, 0.9–6.6 cm) and the most commonly involved temporal bone subsites were the middle ear and mastoid (71% each). MM was ultimately diagnosed in six cases (86%). In addition to the new cases presented herein, 18 previously published reports were analyzed. In the 25 aggregate cases, 44% of cases were associated with MM, and the mastoid (72%) and middle ear (53%) were the most commonly involved temporal bone subsites. Conclusion: Plasmacytoma of the temporal bone is rare, and the clinical presentation can closely mimic that of other primary temporal bone tumors. In patients with an established history of MM, it is imperative to have a high index of suspicion for temporal bone plasmacytoma, even when radiological features suggest an alternate diagnosis.

ObjectivesTo elucidate the clinical behavior, treatment, and outcomes of tenosynovial giant cell tumors (TGCT) involving the temporomandibular joint (TMJ) and adjacent temporal bone.Study DesignRetrospective case series with histopathologic review.MethodsA retrospective chart review was performed identifying and collecting data from all cases of TGCT involving the TMJ and adjacent temporal bone that were treated at the authors' center between January 1960 and December 2015.ResultsEleven histopathologically confirmed cases met inclusion criteria. The median age at diagnosis was 49 years, eight patients were men, and the median follow‐up was 116 months. Computed tomographic (CT) imaging revealed a lytic expansile mass centered on the TMJ. Magnetic resonance imaging (MRI) most commonly exhibited hypointense signal on precontrast T1‐ and T2‐weighted sequences and variable postcontrast enhancement. The median delay in diagnosis was 24 months, and the most common presenting symptoms were hearing loss and pain. All patients underwent surgical resection, eight receiving gross total removal, one receiving near total removal, and two patients from early in the series receiving subtotal resection with neoadjuvant or adjuvant radiation. Histopathological review of surgical specimens revealed chondroid metaplasia in seven tumors. Eight of nine cases receiving gross total or near total resection have no evidence of recurrence to date.ConclusionsTGCT of the TMJ and temporal bone are rare and locally aggressive tumors that commonly present with nonspecific symptoms. A careful review of CT and MRI followed by early biopsy is critical in establishing an accurate diagnosis and facilitating appropriate treatment. TGCT of the TMJ more commonly contain chondroid metaplasia when compared to TGCT at other anatomic locations. Gross total resection is achievable in most cases and offers long‐term cure. Radiation may be considered for recurrent disease or adjuvant therapy following subtotal resection.Level of Evidence4. Laryngoscope, 127:2340–2346, 2017

ObjectiveDemonstrate the association of radiographic dural enhancement with increased tumor adherence at the porus acusticus, which may influence completeness of resection and facial nerve outcome.Study DesignCase series with chart review.SettingAcademic referral center.Subjects and MethodsA total of 205 consecutive patients with histopathologically confirmed vestibular schwannoma (VS) were evaluated. Patients with tumors exhibiting dural enhancement on postgadolinium T1‐weighted magnetic resonance imaging were identified and compared with matched controls. Completeness of resection, intraoperative details, and facial nerve outcomes were analyzed.ResultsExcluding strictly intracanalicular tumors (n = 32, 16%) and those with NF2 (n = 10, 4.9%), the presence of dural enhancement was radiographically confirmed in 16 (9.8%) cases. Paired analysis did not reveal significant baseline differences between cases and controls. Subtotal resection was performed in 5 (31%) of the 16 patients with tumors exhibiting dural enhancement, in contrast to 1 (3%) of the matched controls (P =. 01). Four (25%) demonstrated increased tumor adherence at the porus acusticus intraoperatively, compared with 1 control (3%, P =. 04). Long‐term facial nerve function was similar between cases and controls (81% vs 84% House‐Brackmann I‐II function, P = 1.00).ConclusionDural enhancement is present in approximately 10% of extracanalicular VS. Dural enhancement at the porus acusticus may represent hypervascularity, dural reaction, or infiltration, and portends increased tumor adherence and greater likelihood of subtotal resection to preserve facial nerve function. To our knowledge, this is the first series that reports the prevalence of this phenomenon in VS and the potential surgical implications. Recognition preoperatively may be valuable toward patient counseling.

ABSTRACTBACKGROUND/PURPOSEBrain herniation into presumed arachnoid granulations (BHAG) is an increasingly recognized entity. Though it has previously been described as isointense to brain matter on magnetic resonance imaging (MRI), we have encountered 21 cases in our clinical practice, many of which have signal abnormality in the herniated or adjacent parenchyma. We performed a systematic analysis on these cases to further understand the clinical significance.METHODSThis is a retrospective analysis of cases collected from our clinical MRI practice. Each case was evaluated for location, size, lobe of origin, associated signal abnormality, symptoms, and the presence or absence of intracranial hypertension.RESULTSTwenty‐one cases of BHAG identified in 16 patients. Seven cases (7/21, 33%) demonstrated signal abnormality in the herniated or underlying parenchyma. On serial imaging, the size of herniation either fluctuated (2/10, 20%) or stayed the same (8/10, 80%). The associated signal abnormalities increased (1/5, 20%), decreased (1/5, 20%), or remained stable (3/5, 60%). Four patients (4/16, 25%) had signs/symptoms that could be associated with the BHAG. Ten patients (10/16, 63%) had either imaging findings or clinical signs that could be associated with intracranial hypertension.CONCLUSIONIn contrast to previously reported cases, our study demonstrates that BHAG can be associated with MRI signal abnormalities of the herniated and adjacent brain. Symptoms are typically absent, though may be present in a small subset of patients, regardless of the presence of signal change or encephalomalacia of the involved brain. Indirect evidence of intracranial hypertension is present in a majority of patients but completely lacking in others.