Citations

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.

AbstractAfter decades on the margins of primary health care, surgical and anaesthesia care is gaining increasing priority within the global development arena. The 2015 publications of the Disease Control Priorities third edition on Essential Surgery and the Lancet Commission on Global Surgery created a compelling evidenced‐based argument for the fundamental role of surgery and anaesthesia within cost‐effective health systems strengthening global strategy. The launch of the Global Alliance for Surgical, Obstetric, Trauma, and Anaesthesia Care in 2015 has further coordinated efforts to build priority for surgical care and anaesthesia. These combined efforts culminated in the approval of a World Health Assembly resolution recognizing the role of surgical care and anaesthesia as part of universal health coverage. Momentum gained from these milestones highlights the need to identify consensus goals, targets and indicators to guide policy implementation and track progress at the national level. Through an open consultative process that incorporated input from stakeholders from around the globe, a global target calling for safe surgical and anaesthesia care for 80% of the world by 2030 was proposed. In order to achieve this target, we also propose 15 consensus indicators that build on existing surgical systems metrics and expand the ability to prioritize surgical systems strengthening around the world.

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 novel case of congenital profound bilateral sensorineural hearing loss in a patient with bilateral nodular internal auditory canal and labyrinthine enhancement and temporal bone dysplasia. Patients: A 76-day-old female was referred to the authors’ center for evaluation of congenital deafness. Behavioral observations and objective audiometric evaluation demonstrated bilateral profound sensorineural hearing loss and a comprehensive multidisciplinary evaluation identified compound heterozygous pathogenic variants in MYO7A , a gene associated with Usher Syndrome Type 1B or DFNB2. Computed tomography and contrast-enhanced magnetic resonance imaging studies demonstrated bilateral temporal bone anomalies with unique middle and inner ear malformations, as well as unique contrast enhancement in the membranous labyrinth, internal auditory canals, and cranial nerves, which have not been previously described with MYO7A variants. Interventions: Given the potential risk for progressive bilateral labyrinthitis ossificans, bilateral simultaneous cochlear implantation was performed at 4 months of age. Main Outcome Measures: Subsequent audiologic follow up after implantation shows significantly improved access to auditory information and increased vocalizations. At last testing, speech and language skills for both receptive and expressive language abilities were found to be commensurate with her chronological age. Conclusion: We report a novel presentation and imaging findings of congenital bilateral profound sensorineural hearing loss in a patient with nodular internal auditory canal and labyrinthine enhancement and coexisting inner ear dysplasia. Despite the multiple radiologic abnormalities, the patient has demonstrated good benefit from cochlear implantation. Future study of rare variants of congenital deafness, such as this, is critical toward defining new disease processes and determining optimal treatment.

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.

321 Background: Factors that determine renal function after partial nephrectomy (PN) are not well defined, including the impact of cold vs. warm ischemia and the relative importance of modifiable and non-modifiable factors. We studied these determinants in a large cohort of patients with a solitary functioning kidney undergoing PN. Methods: In 1980–2009, 660 PN were performed at 4 centers for tumor in a solitary-functioning kidney under cold (n=300) or warm (n=360) ischemia. Data were collected in IRB-approved registries; follow- up averaged 4.5 years. Pre- and postoperative glomerular filtration rates (GFR) were estimated via CKD-EPI equation. Results: At 3 months after PN, median GFR decreased by equivalent amounts with cold or warm ischemia (21% vs. 22%, respectively, p=0.7) although median cold ischemic times were much longer (45 vs. 22 min. respectively, p<0.001). In multivariable analyses, increasing age, larger tumor size, lower preoperative GFR, and longer ischemia time were associated with decreased postoperative GFR (p<0.05). When percentage of parenchyma spared was incorporated into the analysis, this factor and preoperative GFR proved to be the primary determinants of ultimate renal function, and duration of ischemia lost statistical significance. Conclusions: This non-randomized comparative study suggests that long-term renal function after PN is determined primarily by the quantity and quality of renal parenchyma that can be preserved. Within the relatively strict parameters of conventional practice, i.e. predominantly short ischemic intervals and liberal use of hypothermia, ischemia time was not an independent predictor of ultimate renal function after PN. Nevertheless, type and duration of ischemia remain the most important modifiable factors during PN, and mandate further study. [Table: see text]