Two Cases of Intraoperative ECG Artifact Mimicking Ventricular Tachycardia and How to Know When It Is Real.

Electrocardiographic (ECG) artifacts may resemble ventricular tachycardia (VT), leading to inappropriate therapies. Despite extensive training, electrophysiologists have still been shown to misinterpret artifacts. The literature is scant regarding the intraoperative identification by anesthesia providers of ECG artifacts resembling VT. We present two cases of the intraoperative occurrence of ECG artifacts resembling VT. The first case involved a patient undergoing extremity surgery after receiving a peripheral nerve block. The patient was treated with a lipid emulsion for a presumptive local anesthetic systemic toxicity diagnosis. The second case was a patient with an implantable cardiac defibrillator (ICD) with suspended anti-tachycardia functionality due to the location of the surgery in the region of the ICD generator. The second case's ECG was identified as an artifact, and no treatment was initiated. Misinterpretation of intraoperative ECG artifacts continues to lead clinicians to institute unnecessary therapies. Our first case occurred in the context of a peripheral nerve block leading to the misdiagnosis of local anesthetic toxicity. The second case occurred during the physical manipulation of the patient during liposuction.

Magnetic Resonance Imaging Findings in High School Football Players: Brain and Cervical Spine.

Football exposes its players to traumatic brain, neck, and spinal injury. It is unknown whether the adolescent football player develops imaging abnormalities of the brain and spine that are detectable on magnetic resonance imaging (MRI). The objective of this observational study was to identify potential MRI signatures of early brain and cervical spine (c-spine) injury in high school football players. Eighteen football players (mean age, 17.0 ± 1.5 years; mean career length, 6.3 ± 4.0 years) had a baseline brain MRI, and 7 had a follow-up scan 9-42 months later. C-spine MRIs were performed on 11 of the 18 subjects, and 5 had a follow-up scan. C-spine MRIs from 12 age-matched hospital controls were also retrospectively retrieved. Brain MRIs were reviewed by a neuroradiologist, and no cerebral microbleeds were detected. Three readers (a neuroradiologist, a neurosurgeon, and an orthopedic spine surgeon) studied the cervical intervertebral discs at six different cervical levels and graded degeneration using an established five-grade scoring system. We observed no statistically significant difference in disc degeneration or any trend toward increased disc degeneration in the c-spine of football players as compared with age-matched controls. Further research is needed to validate our findings and better understand the true impact of contact sports on young athletes.

Automated in vivo Assessment of Vascular Response to Radiation using a Hybrid Theranostic X-ray Irradiator/Fluorescence Molecular Imaging System.

Hypofractionated stereotactic body radiotherapy treatments (SBRT) have demonstrated impressive results for the treatment of a variety of solid tumors. The role of tumor supporting vasculature damage in treatment outcome for SBRT has been intensely debated and studied. Fast, non-invasive, longitudinal assessments of tumor vasculature would allow for thorough investigations of vascular changes correlated with SBRT treatment response. In this paper, we present a novel theranostic system which incorporates a fluorescence molecular imager into a commercial, preclinical, microCT-guided, irradiator and was designed to quantify tumor vascular response (TVR) to targeted radiotherapy. This system overcomes the limitations of single-timepoint imaging modalities by longitudinally assessing spatiotemporal differences in intravenously-injected ICG kinetics in tumors before and after high-dose radiation. Changes in ICG kinetics were rapidly quantified by principle component (PC) analysis before and two days after 10 Gy targeted tumor irradiation. A classifier algorithm based on PC data clustering identified pixels with TVR. Results show that two days after treatment, a significant delay in ICG clearance as measured by exponential decay (40.5±16.1% P=0.0405 Paired t-test n=4) was observed. Changes in the mean normalized first and second PC feature pixel values (PC1 & PC2) were found (P=0.0559, 0.0432 paired t-test), suggesting PC based analysis accurately detects changes in ICG kinetics. The PC based classification algorithm yielded spatially-resolved TVR maps. Our first-of-its-kind theranostic system, allowing automated assessment of TVR to SBRT, will be used to better understand the role of tumor perfusion in metastasis and local control.

Vibrotactile display design: Quantifying the importance of age and various factors on reaction times.

Numerous factors affect reaction times to vibrotactile cues. Therefore, it is important to consider the relative magnitudes of these time delays when designing vibrotactile displays for real-time applications. The objectives of this study were to quantify reaction times to typical vibrotactile stimuli parameters through direct comparison within a single experimental setting, and to determine the relative importance of these factors on reaction times. Young (n = 10, 21.9 ± 1.3 yrs) and older adults (n = 13, 69.4 ± 5.0 yrs) performed simple reaction time tasks by responding to vibrotactile stimuli using a thumb trigger while frequency, location, auditory cues, number of tactors in the same location, and tactor type were varied. Participants also performed a secondary task in a subset of the trials. The factors investigated in this study affected reaction times by 20-300 ms (reaction time findings are noted in parentheses) depending on the specific stimuli condition. In general, auditory cues generated by the tactors (<20 ms), vibration frequency (<20 ms), number of tactors in the same location (<30 ms) and tactor type (<50 ms) had relatively small effects on reaction times, while stimulus location (20-120 ms) and secondary cognitive task (>130 ms) had relatively large effects. Factors affected young and older adults' reaction times in a similar manner, but with different magnitudes. These findings can inform the development of vibrotactile displays by enabling designers to directly compare the relative effects of key factors on reaction times.

Blood Pressure Is Associated with Receiving Intravitreal Anti-Vascular Endothelial Growth Factor Treatment in Patients with Diabetes.

PURPOSE: Intravitreal anti-vascular endothelial growth factor (VEGF) injections are used commonly in the treatment of diabetic retinopathy (DR), but the need for treatment and frequency of administration vary considerably among patients. There is no way to predict which patients will require treatment and how frequently injections will be needed. This study aimed to identify factors associated with receiving anti-VEGF injections and the number of treatments received in an 18-month period in patients with diabetes. DESIGN: Retrospective cohort study. PARTICIPANTS: Two thousand nine hundred sixteen patients with diabetes treated at the Kellogg Eye Center Retina Clinic from June 1, 2016, through December 31, 2017. METHODS: Retrospective analysis was performed with institutional review board approval using data collected from diabetic patients treated at the retina clinic at the Kellogg Eye Center. Logistic regression was used to identify demographic and medical factors associated with receiving at least 1 injection. Negative binomial regression was used to model the number of anti-VEGF injections. MAIN OUTCOME MEASURES: Receiving at least 1 anti-VEGF injection and the number of anti-VEGF injections received during the study period. RESULTS: Systolic blood pressure and a diagnosis of DR were associated significantly with receiving an injection. A history of kidney disease was associated positively with the number of injections received. Type 1 diabetes was associated negatively with receiving an injection and the number of injections. Current hemoglobin A1c level was not associated with either receiving an injection or the number of injections. CONCLUSIONS: Elevated blood pressure is associated significantly with the need for treatment with anti-VEGF injections in patients with diabetes, and a diagnosis of type 1 diabetes is associated negatively with both receiving treatment and the number of injections. Of note, current glycemic control is not associated significantly with either outcome measure. To our knowledge, these associations have not been previously reported, and imply that factors that confer risk for DR development may not be the same that confer risk for treatment.

The effects of sequential treatments on hippocampal volumes in malignant glioma patients.

Malignant gliomas (MG) are very aggressive tumors. In an effort to improve the outcome, the patients receive multi-modal therapies such as surgery, radiation and chemotherapy (temozolomide followed in many cases by bevacizumab). The survivors are affected by multiple learning and memory deficits. Greater deterioration over time in hippocampal specific cognitive tasks was shown in patients receiving bevacizumab in addition to radiation and temozolomide for a longer period of time (RTOG 0825). The rate of hippocampal atrophy in patients treated with radiation and temozolomide followed by bevacizumab is not yet determined, and is the goal of the present study. We used the serial MRIs obtained as parts of standard clinical care in patients with MG. Measurements were done using the Medical Image Processing, Analysis and Visualization (MIPAV) software. The hippocampus in the contralateral hemisphere was manually traced and measured, to avoid morphological structure changes induced by the tumor, radiation fields or surgical markers. We determined a longitudinal progression of hippocampal atrophy-with the maximum volume loss (33.26 %) for the patients that were on treatment for 5 years. There was no detectable hippocampal atrophy during the chemo-radiation followed by adjuvant temozolomide. A significant decrease in the absolute hippocampus volume was noted after 6 months of continuous bevacizumab treatment (p < 0.05). The hippocampal volume loss progressed over the next 3 years, and was higher than the one previously reported in Alzheimer disease patients. The hippocampal volume loss is minimal during the 1 month after diagnosis, when the patients receive chemo-radiation and adjuvant temozolomide. However, prolonged treatment including bevacizumab is associated with a significant rate of hippocampal volume loss.

Shape of the basal ganglia in preadolescent children is associated with cognitive performance.

Current studies support the belief that high levels of performance and intellectual abilities are associated with increased brain size or volume. With few exceptions, this conclusion is restricted to studies of post-adolescent subjects and to cerebral cortex. There is evidence that "bigger is better" may not pertain to children and further, that there are areas of the brain in which larger structures are associated with cognitive deficits. In 50 preadolescent children (21 girls) a structural survey of the brain (VBM) was conducted to determine and locate areas in which gray matter volume was associated with poor cognitive performance. Only increased gray matter volume in particular areas of the basal ganglia and specifically the putamen was significantly associated with poor performance on tests of memory, response speed and a general marker and subtests of intelligence. Based on the VBM findings, volumetric analysis of basal ganglia structures was performed using FSL/FIRST. However, no significant changes in total volume of putamen or other basal ganglia structures were detected with this analysis. The disagreement between measures of localized gray matter differences and volumetric analysis suggested that there might be local regional deformity rather than widespread volumetric changes of the putamen. Surface analysis with FSL/FIRST demonstrated that bilateral outward deformation of the putamen, but especially the left, was associated with poor performance on several cognitive tests. Expansion of the globus pallidus and caudate nucleus also was associated with poor performance. Moreover a significant association was detected between a reliable test of language-free intelligence and topographically distinct outward and inward deformation of the putamen. Expansion and contraction of the putamen as a predictor of intelligence may explain why this association was not observed with measures of total volume. These results suggest that deformity is a sensitive measure of function, and that distortion of the basal ganglia may be a neurophenotype for risk of developmental impairment.

[Multi-modality magnetic resonance imaging features of cognitive function in mild cognitive impairment].

OBJECTIVE: To investigate the association of multi-modality neuroimaging features and cognitive function in mild cognitive impairment (MCI) and Alzheimer's disease (AD). METHODS: Nine individuals with amnestic MCI (aMCI), fifteen patients with mild probable AD, and eleven age-controlled cognitively normal controls (NC) were recruited. All participants were administered with mini-mental status examination (MMSE) and Cognitive assessment screening instrument (CASI) to assess general cognitive function. Optimized voxel-based morphometry (VBM) was used for the analysis with 3-D high resolution anatomical images. Values of fractional anisotropy (FA) and mean apparent diffusivity coefficient (ADC) were measured from different brain regions on diffusion-tensor images (DTI). The relationship between structural atrophy and DTI-based measurements in the selected brain regions was examined. RESULTS: The scores of MMSE and CASI were correlated with the volumetric changes in such areas as temporal, frontal and parietal lobes, and cingulate gyrus and hippocampal gyrus (P<0.001). The scores of MMSE and CASI were positively correlated with FA values, and negatively with ADC values in the white-matter-affected regions including temporal, frontal, parietal lobes, cingulate gyrus, and parahippocampal gyrus (P<0.05). CONCLUSIONS: Cognitive decline was associated with atrophy and white matter microstructural alterations in temporal, frontal, parietal lobes, cingulate gyrus, and parahippocampal gyrus in MCI and AD. Multi-modality imaging technique may be important in elucidating the brain mechanism of cognitive impairment.