Cognitive and Cellular Effects of Combined Organophosphate Toxicity and Mild Traumatic Brain Injury.

Traumatic brain injury (TBI) is considered the most common neurological disorder among people under the age of 50. In modern combat zones, a combination of TBI and organophosphates (OP) can cause both fatal and long-term effects on the brain. We utilized a mouse closed-head TBI model induced by a weight drop device, along with OP exposure to paraoxon. Spatial and visual memory as well as neuron loss and reactive astrocytosis were measured 30 days after exposure to mild TBI (mTBI) and/or paraoxon. Molecular and cellular changes were assessed in the temporal cortex and hippocampus. Cognitive and behavioral deficits were most pronounced in animals that received a combination of paraoxon exposure and mTBI, suggesting an additive effect of the insults. Neuron survival was reduced in proximity to the injury site after exposure to paraoxon with or without mTBI, whereas in the dentate gyrus hilus, cell survival was only reduced in mice exposed to paraoxon prior to sustaining a mTBI. Neuroinflammation was increased in the dentate gyrus in all groups exposed to mTBI and/or to paraoxon. Astrocyte morphology was significantly changed in mice exposed to paraoxon prior to sustaining an mTBI. These results provide further support for assumptions concerning the effects of OP exposure following the Gulf War. This study reveals additional insights into the potentially additive effects of OP exposure and mTBI, which may result in more severe brain damage on the modern battlefield.

Virtual reality utilization for left atrial appendage occluder device size prediction.

Aim: To explore the feasibility and accuracy of virtual reality (VR) derived from cardiac computed angiography (CCTA) data to predict left atrial appendage occlusion (LAAO) device size. Method: Retrospective data of patients who underwent LAAO according to clinical indication were reviewed; all patients underwent a pre-procedural CCTA. Measurements of the left atrial appendage (LAA) orifice diameters by CCTA, VR, and transesophageal echocardiography (TEE) (acquired during the procedure) were compared to the implanted device size. The LAA perimeter was calculated using the Ramanujan approximation. Statistical analyses included Lin's Concordance Correlation Coefficient (ρ c ), the mean difference, and the mean square error (MSE). Results: The sample was composed of 20 patients (mean age 75.7 ± 7.5 years, 60% males) who underwent successful LAAO insertion (ACP™ N = 8, Watchman™ N = 12). The CCTA, VR, and TEE maximal diameter ρ c was 0.52, 0.78 and 0.60, respectively with mean differences of +0.92 ± 4.0 mm, -1.12 ± 2.3 mm, and -3.45 ± 2.69 mm, respectively. The CCTA, VR, and TEE perimeter calculations ρ c were 0.49, 0.54, and 0.39 respectively with mean differences of +4.69 ± 11.5 mm, -9.88 ± 8.0 mm, and -16.79 ± 7.8 respectively. Discussion: A VR visualization of the LAA ostium in different perspectives allows for a better understanding of its funnel-shaped structure. VR measurement of the maximal ostium diameter had the strongest correlation with the diameter of the inserted device. VR may thus provide new imaging possibilities for the evaluation of complex pre-procedural structures such as the LAA.

Using Virtual Reality for Deep Inferior Epigastric Perforator Flap Preoperative Planning.

This study was designed to compare VR stereoscopical three-dimensional (3D) imaging with two-dimensional computed tomography angiography (CTA) images for evaluating the abdominal vascular anatomy before autologous breast reconstruction. Methods: This prospective case series feasibility study was conducted in two tertiary medical centers. Participants were women slated to undergo free transverse rectus abdominis muscle, unilateral or bilateral deep inferior epigastric perforator flap immediate breast reconstruction. Based on a routine CTA, a 3D VR model was generated. Before each procedure, the surgeons examined the CTA and then the VR model. Any new information provided by the VR imaging was submitted to a radiologist for confirmation before surgery. Following each procedure, the surgeons completed a questionnaire comparing the two methods. Results: Thirty women between 34 and 68 years of age were included in the study; except for one, all breast reconstructions were successful. The surgeons ranked VR higher than CTA in terms of better anatomical understanding and operative anatomical findings. In 72.4% of cases, VR models were rated having maximum similarity to reality, with no significant difference between the type of perforator anatomical course or complexity. In more than 70% of the cases, VR was considered to have contributed to determining the surgical approach. In four cases, VR imaging modified the surgical strategy, without any complications. Conclusions: VR imaging was well-accepted by the surgeons who commented on its importance and ease compared with the standard CTA presentation. Further studies are needed to determine whether VR should become an integral part of preoperative deep inferior epigastric perforator surgery planning.

Proof of concept: Comparative accuracy of semiautomated VR modeling for volumetric analysis of the heart ventricles.

Introduction: Simpson's rule is generally used to estimate cardiac volumes. By contrast, modern methods such as Virtual Reality (VR) utilize mesh modeling to present the object's surface spatial structure, thus enabling intricate volumetric calculations. In this study, two types of semiautomated VR models for cardiac volumetric analysis were compared to the standard Philips dedicated cardiac imaging platform (PDP) which is based on Simpson's rule calculations. Methods: This retrospective report examined the cardiac computed tomography angiography (CCTA) of twenty patients with atrial fibrillation obtained prior to a left atrial appendage occlusion procedure. We employed two VR models to evaluate each CCTA and compared them to the PDP: a VR model with Philips-similar segmentations (VR-PS) that included the trabeculae and the papillary muscles within the luminal volume, and a VR model that only included the inner blood pool (VR-IBP). Results: Comparison of the VR-PS and the PDP left ventricle (LV) volumes demonstrated excellent correlation with a ρ c of 0.983 (95% CI 0.96, 0.99), and a small mean difference and range. The calculated volumes of the right ventricle (RV) had a somewhat lower correlation of 0.89 (95% CI 0.781, 0.95), a small mean difference, and a broader range. The VR-IBP chamber size estimations were significantly smaller than the estimates based on the PDP. Discussion: Simpson's rule and polygon summation algorithms produce similar results in normal morphological LVs. However, this correlation failed to emerge when applied to RVs and irregular chambers. Conclusions: The findings suggest that the polygon summation method is preferable for RV and irregular LV volume and function calculations.

Using Augmented Reality for Intraoperative Guidance During Sacral Neuromodulation System Implantation.

Objective: The purpose of this study was to examine the feasibility of using augmented reality during lead placement for sacral nerve stimulation (SNS). Methods: The study was a prospective case series performed in a single tertiary center. Patients with fecal incontinence or urinary retention eligible for SNS according to the American society of colon and rectal surgeon's guidelines were included. Each patient underwent a computerized tomography scan of the sacrum and pelvic floor before surgery; and a segmentation of the sacral bone, the skin, and three fiducial markers on the lower back was produced. Surgical planning included the design of an ideal virtual transmission tract leading to the S3 foramen using the most suitable location and needle trajectory for introducing the lead. During the surgical intervention, a needle was inserted into the S3 foramen using the aligned tract as visualized using the Microsoft HoloLens first generation head mounted unit. Results: Overall, 11 patients were included. Mean operative time was 43.8 minutes (range 25-81 minutes). All patients reported a significant reduction from the preoperative level of the mean postoperative Cleveland Clinic Incontinence Score (CCIS) assessed 2 weeks after the temporary SNS implant (CCIS preoperative 13.3, postoperative 8.5; CI -7.35 to -2.25; P < 0.01). The surgeons reported the imaging useful, allowing accurate and easier approach. Conclusions: Intraoperative augmented reality imaging for needle application during SNS appears to be feasible, practical, and may be useful in additional procedures.

GM1 ganglioside prevents axonal regeneration inhibition and cognitive deficits in a mouse model of traumatic brain injury.

Traumatic Brain Injury (TBI) is one of the most common causes of neurological damage in young populations. It has been previously suggested that one of the mechanisms that underlie brain injury is Axonal Outgrowth Inhibition (AOI) that is caused by altered composition of the gangliosides on the axon surface. In the present study, we have found a significant reduction of GM1 ganglioside levels in the cortex in a closed head traumatic brain injury model of a mouse, induced by a weight drop device. In addition, axonal regeneration in the brains of the injured mice was affected as seen by the expression of the axonal marker pNF-H and the growth cones (visualized by F-actin and ß-III-tubulin). NeuN immunostaining revealed mTBI-induced damage to neuronal survival. Finally, as expected, spatial and visual memories (measured by the Y-maze and the Novel Object Recognition tests, respectively) were also damaged 7 and 30 days post injury. A single low dose of GM1 shortly after the injury (2 mg/kg; IP) prevented all of the deficits mentioned above. These results reveal additional insights into the neuroprotective characteristics of GM1 in prevention of biochemical, cellular and cognitive changes caused by trauma, and may suggest a potential intervention for mTBI.