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This paper presents a simulation system (“patient model”) for intraoperative neuromonitoring (IONM) applied to mastoidectomy. IONM is an electrophysiological method for monitoring the integrity and localization of nerve tracts, which helps the surgeon to avoid injuries and damage to neural risk structures (e.g. facial nerve) during surgery. To use the IONM successfully, the surgeon needs appropriate training and experience. The presented simulation system provides training possibilities in a realistic, cost-efficient and reproducible way. In the simulation system, the position of the probe during training is determined by a magnetic tracking method. Depending on the distance to the virtual nerve, a synthetic electromyogram (EMG) signal is sent to a real neuromonitor. The trainee learns to interpret the output of the neuromonitor. The trainer can choose different training scenarios, such as localization of the nerve, milling or coagulating, using a web application.

Purpose: African-American men (AAM) have a greater risk of hypertension (HTN) than Caucasian men (CM). To reduce this risk, determining the differences in mechanisms involved in HTN and understanding the relationship between these mechanisms and factors affecting blood pressure (BP) in AAM and CM is necessary. One such mechanism is spontaneous baroreflex sensitivity (sBRS) and two factors are cardiorespiratory fitness (CRF) and arterial stiffness (AS). The aims of this study were to determine, firstly, whether there are differences in sBRS between young, normotensive AAM and CM, and secondly, to determine if CRF and AS are significant predictors of sBRS in young, normotensive AAM and CM. Methods: Twenty-three normotensive AAM and 36 CM were recruited from Southern Connecticut State University. Measures included anthropometric, sBRS (alpha-index), and CRF (maximal oxygen consumption [VO2max]), as well as AS (carotid-femoral pulse wave velocity [Cf-PWV]). Independent t-tests were used to determine differences between groups and multiple regression analysis was used to determine how much of the variation in sBRS was explained by CRF and AS. Results: The sBRS was significantly lower in AAM (10.3 ± 3.8 ms/mmHg) vs. CM (13.3 ± 5.7 ms/ mmHg), P = 0.03. CRF and AS were not significant predictors of sBRS in AAM (P = 0.25) and CM (P = 0.30). There was no relationship between, sBRS, CRF and AS; CRF was significantly reduced in AAM vs. CM (45.1 ± 6.3 vs. 52.1 ± 7.5 mL·kg−1·min−1, P ≤ 0.001). Conclusions: Young normotensive AAM demonstrated significantly lower sBRS vs. CM, irrespective of having fair CRF and normal BP. CRF and AS are not significant predictors of sBRS in young, normotensive AAM and CM. The attenuation in sBRS in AAM did not result in AAM having higher BP versus CM. This finding underscores the need for more detailed examination of the role of sBRS in the etiology of HTN in AAM.

Purpose: Aortic augmentation index (AIx) and cardiovagal tone (CVT) are indicators of cardiovascular health. Associations between these variables provide information about their roles in cardiovascular disease. However, evaluating these associations from a gender perspective and gaining an understanding of the relationship between cardiorespiratory fitness and AIx based on gender can provide additional information. Therefore, we examined the relationships between CVT, measured as the log transformed high-frequency power of R-R intervals from electrocardiogram measurements (lnHFR-R); cardiorespiratory fitness, measured as maximum oxygen consumption (VO2max); and AIx at a heart rate of 75 beats·min-1(AIx@75). We hypothesized that the relationships between CVT, cardiorespiratory fitness, and AIx@75 would differ based on gender. Methods: We examined the associations between lnHFR-R, VO2max, and AIx@75 in 41 women and 39 men. Power spectral density analysis of heart rate variability determined lnHFR-R, radial tonometry determined AIx@75 and the Bruce Treadmill Protocol determined VO2max. Results: In men, lnHFR-R positively correlated with and significantly predicted AIx@75 (P = 0.005) but not in women (P = 0.49). For every unit increase in lnHFR-R, there was a 4.6 unit increase in AIx@75 in men versus a 1.0 unit increase in women. There was a significant inverse relationship between VO2max and AIx@75, with VO2max being a significant predictor of AIx@75 in men (P = 0.01). For every unit increase in VO2max, there was a 0.60 unit decrease in AIx@75 in men versus a 0.2 unit decrease in women. Conclusions: The associations between CVT and AIx@75 and between cardiorespiratory fitness and AIx@75 differ by gender. CVT and cardiorespiratory fitness are significant predictors of AIx@75 in men but not in women.

To investigate the frequency of pancreatic duct (PD) variants and their effect on pancreatic exocrine function in a population-based study using non-invasive secretin-stimulated magnetic resonance cholangiopancreatography (sMRCP).Nine hundred and ninety-five volunteers, 457 women and 538 men, aged 51.9 ± 13.4 years, underwent navigator-triggered, T2-weighted, 3D turbo spin echo MRCP on a 1.5 T system after 1 unit/kg secretin administration. Two readers evaluated images for PD variants. Pancreatic exocrine function and morphological signs of chronic pancreatitis such as abnormalities of the main PD, side branch dilatation, and pancreatic cysts were evaluated and related to PD variants using a Kruskal-Wallis test and post hoc analysis.Of all sMRCP, 93.2% were of diagnostic quality. Interobserver reliability for detection of PD variants was found to be kappa 0.752 (95 %CI, 0.733 - 0.771). Normal PD variants were observed in 90.4% (n = 838/927). Variants of pancreas divisum was identified in 9.6% (n = 89/927). Abnormalities of the main PD, side branch dilatation, and pancreatic cysts were observed in 2.4%, 16.6%, and 27.7%, respectively, and were not significantly different between pancreas divisum and non-divisum group (P = 0.122; P = 0.152; P = 0.741). There was no association between PD variants and pancreatic exocrine function (P = 0.367).PD variants including pancreas divisum are not associated with morphological signs of chronic pancreatitis or restriction of pancreatic exocrine function.MRCP allows the evaluation of pancreatic duct variants and morphological change. Pancreatic duct variants are not associated with morphological signs of chronic pancreatitis. Pancreas divisum is not accompanied by restriction of pancreatic exocrine function. Pancreatic duct variants including pancreas divisum are limited in their clinical relevance.

To investigate three-echo T2*-corrected Dixon magnetic resonance imaging (MRI) for noninvasively estimating hepatic fat content (HFC) compared with biopsy.One hundred patients (50 men, 50 women; mean age, 57.7±14.2 years) underwent clinically indicated liver core biopsy (102 valid tissue samples) and liver MRI 24 to 72 hours later. MRI was performed at 1.5T (Magnetom Avanto, Siemens Healthcare, Erlangen, Germany) using Dixon imaging with T2* correction (work in progress, WIP-432.rev.1, Siemens Healthcare). An ultrafast breath-hold three-echo 3D-gradient echo sequence with TR/TE1/TE2/TE3 of 11/2.4/4.8/9.6 milliseconds, and online calculation of T2*-corrected water images (signal intensities of water [SIW]), fat images (SIF), and fat content map (SIFAT=10×SIF/(SIW+SIF)) was used. SIs of the calculated fat content map (SIFAT) were verified using the histologically quantified HFC (HFC(path)). Spearman correlation for HFC(path) and SIFAT was calculated. Stage of fibrosis, hepatic iron content, and patterns of liver fat (macrovesicular, microvesicular, mixed) and their influence on predicting HFC by MRI were determined.Correlation between SIFAT and HFC(path) was rspearman=0.89. Agreement between HFC predicted by MRI and HFC(path) calculated by nonlinear saturation-growth regression was rspearman=0.89. Kruskal-Wallis analysis revealed no significant difference for SIFAT across fibrosis grades (P=0.90) and liver iron content (P=0.76). Regarding the cellular architecture of liver fat, the microvesicular pattern showed lower mean ranks in SI than macrovesicular and mixed patterns (P=0.01).T2*-corrected Dixon MRI is a noninvasive tool for estimating HFC, showing excellent correlation with liver biopsy without being limited by liver iron content and fibrosis/cirrhosis.

Background: Cardiovascular disease is a primary cause of death worldwide. Low parasympathetic nervous activity (PNA) is associated with negative cardiovascular health (CVH) [1]. Central augmentation pressure (CAP), aortic pulse pressure (APP) and augmentation index (Alx) are all strong indicators of CVH. Heart rate variability (HRV) and recovery heart rate (RHR) are both indices of PNA but they do not correlate [2]. Since these indices do not correlation we hypothesized that there would be a difference in their relationship with CVH as determined by CAP, APP and Alx75. Aim: To determine if there is a difference in the relationships between HRV, RHR and CAP, APP and Alx inmen. Methods: Seventeen healthy college aged men were examined for HRV via power spectral density analysis. Recovery heart rate was examined at minute one (RHR1) and two (RHR 2)) following a VO2max test. Pulse wave analysis via applanation tonometry and a generalized transfer function was used to determine CAP, APP and Alx. Results: There was a significant correlation between HRV and CAP (r = 0.61, P = 0.01) and Alx (r = 0.51, P = 0.05). No correlation was observed between RHR 1, RHR 2 and CAP, Alx and APP. Central augmentation pressure was significantly correlated with APP (r = 0.67, P= 0.01) and Alx r = 0.64, P= 0.01). Conclusions: Findings suggest a difference in the relationship between HRV, RHR and CVH. Here HRV was positively correlated with indices of CVH, while RHR did not correlate with these indices. Indicating that HRV seem to be more indicative of CVH versus RHR.

643 Background: Many reports have shown the prognostic value of HER-2 measured in tumor tissue or in blood. In 2009, Finn et.al. showed that in a study of 579 MBC patients whose serum HER-2 levels (sHER-2) were constantly below normal had a longer PFS than patients with a sHER-2 level constantly above normal. Patients who converted from above normal to less than normal during therapy had a longer PFS than the opposite change. Methods: We performed a Bayesian meta-analysis of 12 studies where all sHER-2 levels were measured using an FDA cleared sHER-2 test with a standard cutoff of 15ng/ml. We chose a Bayesian approach because a “meta-analysis” is a natural extension of the Bayesian view that current knowledge is the result of prior knowledge modified by the data. After an in depth literature search, we selected 12 publications based on the following criteria. Baseline levels were available from either early stage or late stage patients who had at least a 2 year disease free or progression free survival as indicated by a Kaplan-Meier (K-M) curve. Results: The analysis included 4030 BC patients of which 1106 patients had baseline levels < 15ng/ml and 2924 patients had baseline values >15ng/ml. From the K-M curves, we estimated the number of recurrences up to 24 months in each group and prepared a 2x2 table for each study. We determined the odds ratio (OR) for the 12 studies which ranged from 0.57 to 74. A posterior distribution for the aggregated 12 studies can be represented by a Dirichlet distribution. 10,000 estimates of the aggregated OR indicated that there is a 95% credibility that the odds of a woman with baseline sHER-2 >15ng/ml recurring at or before two years is between 3.39 and 4.57 times higher than the odds of a woman whose baseline sHER-2 was < 15ng/ml recurring at or before two years. Conclusions: This meta-analysis agrees with previous studies that serum HER-2 levels > 15ng/ml can be a strong prognostic indicator for women with Breast Cancer and that managing therapy regimens to maximize the decrease in serum HER-2 levels could be important target in treating patients.