Polarimetric imaging for the detection of synthetic models of SARS-CoV-2: A proof of concept.

Objective: To conduct a proof-of-concept study of the detection of two synthetic models of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) using polarimetric imaging. Approach: Two SARS-CoV-2 models were prepared as engineered lentiviruses pseudotyped with the G protein of the vesicular stomatitis virus, and with the characteristic Spike protein of SARS-CoV-2. Samples were prepared in two biofluids (saline solution and artificial saliva), in four concentrations, and deposited as 5-µL droplets on a supporting plate. The angles of maximal degree of linear polarization (DLP) of light diffusely scattered from dry residues were determined using Mueller polarimetry from87 samples at 405 nm and 514 nm. A polarimetric camera was used for imaging several samples under 380-420 nm illumination at angles similar to those of maximal DLP. Per-pixel image analysis included quantification and combination of polarization feature descriptors in 475 samples. Main results: The angles (from sample surface) of maximal DLP were 3° for 405 nm and 6° for 514 nm. Similar viral particles that differed only in the characteristic spike protein of the SARS-CoV-2, their corresponding negative controls, fluids, and the sample holder were discerned at 10-degree and 15-degree configurations. Significance: Polarimetric imaging in the visible spectrum may help improve fast, non-contact detection and identification of viral particles, and/or other microbes such as tuberculosis, in multiple dry fluid samples simultaneously, particularly when combined with other imaging modalities. Further analysis including realistic concentrations of real SARS-CoV-2 viral particles in relevant human fluids is required. Polarimetric imaging under visible light may contribute to a fast, cost-effective screening of SARS-CoV-2 and other pathogens when combined with other imaging modalities.

Cranial expansion and aqueductoplasty for combined isolated fourth ventricle and slit-ventricle syndrome: a surgical alternative.

INTRODUCTION: An isolated fourth ventricle (IFV) is a rare entity observed in shunted patients and its treatment is still uncertain. Endoscopic aqueductoplasty has shown good results for restoring CSF flux between the third and fourth ventricles. However, it needs some grade of ventricular dilation to be performed. Some patients affected by IFV show slit-ventricle morphology in CT/MRI. Usually, the rise of opening pressure or the shunt externalization gets enough ventricular dilation. However, the lack of intracranial compliance in some patients makes these options unsuitable and high-ICP symptoms are developed without ventricular dilation. METHODS: We present a two cases series affected by IFV with no ventricular dilation in radiological exams. ICP sensors were implanted, observing high-ICP and establishing the diagnosis of craniocerebral disproportion. A two-stage surgical plan based on a dynamic cranial expansion followed by a supratentorial endoscopic aqueductoplasty was performed. A physical and mathematical model explaining our approach was also provided. RESULTS: Chess-table cranial expansion technique was performed in both patients. Six/seven days after the first surgery, respectively, ventricular dilation was observed in CT. Endoscopic precoronal aqueductoplasty was then performed. No postoperative complications were described. IFV symptoms improved in both patients. Eighteen and 12 months after the two-stage surgical plan, the patients remain symptom-free and void of flow is still observed between the third and the fourth ventricles in MRI. CONCLUSION: The two-stage approach was a suitable option for the treatment of these complex patients affected by both craniocerebral disproportion and isolated fourth ventricle.

Contactless Ultrasonic Cavitation for the Prevention of Shunt Obstruction in Hydrocephalus: A Proof-of-Concept Study.

BACKGROUND: Obstructive failure of implanted shunts is the most common complication in the treatment of hydrocephalus. Biological material and debris accumulate in the inner walls of the valve and catheters block the normal flow of the drained cerebrospinal fluid causing severe symptoms with high morbidity and mortality. Unfortunately, at present, there is no effective preventive protocol or cleaning procedure available. OBJECTIVE: To assess whether externally applied, focused ultrasound beams can be used to resuspend deposits accumulated in brain shunts safely. METHODS: A computational model of an implanted brain shunt was implemented to test the initial design parameters of a system comprising several ultrasound transducers. Under laboratory conditions, configurations with 3 and 4 transducers were arranged in a triangle and square pattern with their radiation axis directed towards a target model of the device, 2 catheters and a brain shunt filled with water and deposited graphite powder. The ultrasound beams were then concentrated on the device across a head model. RESULTS: The computational model revealed that by using only 3 transducers, the acoustic field intensity on the valve was approximately twice that on the brain surface suggesting that acoustic cavitation could be selectively achieved. Resuspension of graphite deposits inside the catheters and the valve were then physically demonstrated and video-recorded with no temperature increase. CONCLUSION: The technology presented here has the potential to be used routinely as a noninvasive, preventive cleaning procedure to reduce the likelihood of obstruction-related events in patients with hydrocephalus treated with an implanted shunt.

Optical imaging spectroscopy for rapid, primary screening of SARS-CoV-2: a proof of concept.

Effective testing is essential to control the coronavirus disease 2019 (COVID-19) transmission. Here we report a-proof-of-concept study on hyperspectral image analysis in the visible and near-infrared range for primary screening at the point-of-care of SARS-CoV-2. We apply spectral feature descriptors, partial least square-discriminant analysis, and artificial intelligence to extract information from optical diffuse reflectance measurements from 5 µL fluid samples at pixel, droplet, and patient levels. We discern preparations of engineered lentiviral particles pseudotyped with the spike protein of the SARS-CoV-2 from those with the G protein of the vesicular stomatitis virus in saline solution and artificial saliva. We report a quantitative analysis of 72 samples of nasopharyngeal exudate in a range of SARS-CoV-2 viral loads, and a descriptive study of another 32 fresh human saliva samples. Sensitivity for classification of exudates was 100% with peak specificity of 87.5% for discernment from PCR-negative but symptomatic cases. Proposed technology is reagent-free, fast, and scalable, and could substantially reduce the number of molecular tests currently required for COVID-19 mass screening strategies even in resource-limited settings.

Chest Implantation of Adjustable Gravitational Valves: An Easy, Safe, and Stable Alternative to Control Symptomatic Overdrainage in Shunted Children.

OBJECTIVE: Shunt overdrainage is a potential complication in pediatric hydrocephalus. The addition of adjustable gravitational units to previous shunt systems has been proposed as effective management for this problem. These devices have been traditionally implanted over the occipital bone. We propose chest implantation as an easier, safer, and more stable alternative in the pediatric population, especially in those cases with parieto-occipital shunts. METHODS: This study comprises a retrospective analysis from a unicentric case series of pediatric patients affected by overdrainage and managed with adjustable gravitational valves implanted in the chest. The device implantation technique is described in detail and takes no more than 15 minutes. RESULTS: Thirty-seven patients met the criteria. The mean age of implantation was 9.62 years. The mean follow-up in the series was 38 months. The mean number of pressure adjustments was 2.48. The mean "deviation angle" of the device to the longitudinal body axis was 5.8°. The complications per year of shunt were <0.02 with no disconnection of the catheters in any case during follow-up. CONCLUSIONS: In our experience, chest implantation for adjustable gravitational devices was a suitable shunt modification in pediatric patients suffering from overdrainage.

Modeling chronic cervical spinal cord injury in aged rats for cell therapy studies.

With an expanding elderly population, an increasing number of older adults will experience spinal cord injury (SCI) and might be candidates for cell-based therapies, yet there is a paucity of research in this age group. The objective of the present study was to analyze how aged rats tolerate behavioral testing, surgical procedures, post-operative complications, intra-spinal cell transplantation and immunosuppression, and to examine the effectiveness of human iPSC-derived Neural Progenitor Cells (IMR90-hiPSC-NPCs) in a model of SCI. We performed behavioral tests in rats before and after inducing cervical hemi-contusions at C4 level with a fourth-generation Ohio State University Injury Device. Four weeks later, we injected IMR90-hiPSC-NPCs in animals that were immunosuppressed by daily cyclosporine injection. Four weeks after injection we analyzed locomotor behavior and mortality, and histologically assessed the survival of transplanted human NPCs. As rats aged, their success at completing behavioral tests decreased. In addition, we observed high mortality rates during behavioral training (41.2%), after cervical injury (63.2%) and after cell injection (50%). Histological analysis revealed that injected cells survived and remained at and around the grafted site and did not cause tumors. No locomotor improvement was observed in animals four weeks after IMR90-hiPSC-NPC transplantation. Our results show that elderly rats are highly vulnerable to interventions, and thus large groups of animals must be initially established to study the potential efficacy of cell-based therapies in age-related chronic myelopathies.

Hyperspectral image processing for the identification and quantification of lentiviral particles in fluid samples.

Optical spectroscopic techniques have been commonly used to detect the presence of biofilm-forming pathogens (bacteria and fungi) in the agro-food industry. Recently, near-infrared (NIR) spectroscopy revealed that it is also possible to detect the presence of viruses in animal and vegetal tissues. Here we report a platform based on visible and NIR (VNIR) hyperspectral imaging for non-contact, reagent free detection and quantification of laboratory-engineered viral particles in fluid samples (liquid droplets and dry residue) using both partial least square-discriminant analysis and artificial feed-forward neural networks. The detection was successfully achieved in preparations of phosphate buffered solution and artificial saliva, with an equivalent pixel volume of 4 nL and lowest concentration of 800 TU·[Formula: see text]L-1. This method constitutes an innovative approach that could be potentially used at point of care for rapid mass screening of viral infectious diseases and monitoring of the SARS-CoV-2 pandemic.

Initial experience involving treatment and retreatment with carmustine wafers in combination with oral temozolomide: long-term survival in a child with relapsed glioblastoma multiforme.

BACKGROUND: Glioblastomas occur infrequently in children, and the prognosis is better than for glioblastomas seen in adults. Aggressive treatment is justified in pediatric patients. OBSERVATIONS: We present the case of a 6-year-old child with malignant posterior temporal glioma treated with surgery, radiotherapy, local chemotherapy with carmustine wafers, and oral therapy with temozolomide, both at initial diagnosis and at relapse 18 months later. After 6 years, the patient seems healthy with no focal neurologic signs, and imaging studies show no evidence of disease. CONCLUSION: Multimodal therapy was found to have a very positive outcome for a child with malignant glioma.

Optical analysis of computed tomography images of the liver predicts fibrosis stage and distribution in chronic hepatitis C.

UNLABELLED: This study was undertaken to evaluate an image processing method for assessing liver fibrosis in conventional computed tomography (CT) scans in patients with chronic hepatitis C. Two cohorts (designated "estimation," n = 34; and "validation," n = 107) of chronic hepatitis C patients were assessed using digitized conventional helical CT. Weighted CT mean fibrosis (Fibro-CT) was calculated as a nonlinear weighted mean F-score for each sample. Fibrosis was defined according to Scheuer on the F0 to F4 scale by 2 pathologists blinded regarding the Fibro-CT data. Fibrosis according to Fibro-CT correlated with histology-determined fibrosis (r = 0.69; P < 0.001) and with increasing F-stage: F0 = 0.23 +/- 0.39; F1 = 0.90 +/- 0.99; F2 = 1.41 +/- 0.94; F3 = 2.79 +/- 0.55; F4 = 3.15 +/- 0.35 [analysis of variance: P < 0.0001). The receiver operating characteristics curve to diagnose significant fibrosis (>/=F2) was 0.83; 95% confidence interval (95%CI), 0.75 to 0.91; and, to diagnose advanced fibrosis (>/=F3), was 0.86, 95%CI: 0.80 to 0.93. The correlation between Fibro-CT and fibrosis was higher in patients with homogeneous distribution of fibrosis than in patients with heterogeneous distribution (r = 0.77 versus r = 0.43; P < 0.05). CONCLUSION: Optical digital analysis of CT images of the liver is effective in determining the stage and distribution of liver fibrosis in chronic hepatitis C. In patients with homogeneous fibrosis distribution, the correlation between Fibro-CT and histology was better than in patients with heterogeneous distribution. Fibro-CT is a simple to use, readily available, and useful method for the diagnosis of fibrosis in patients with chronic hepatitis C.

Dynamic Chess-Table Cranial Expansion for Treatment of Craniocerebral Disproportion: Technical Note and Volumetric Results.

OBJECTIVE: Craniocerebral disproportion (CCD) is a challenging disease, and several expansile procedures have been used for its treatment. This report describes the dynamic chess-table cranial expansion technique and reports on 9 patients with primary and secondary CCD treated with this procedure. METHODS: Nine patients affected by CCD were treated with chess-table cranial expansion and reviewed. Symptoms of increased intracranial pressure (ICP) and radiologic findings were analyzed. ICP was monitored using epidural or telemetric sensors. Intracranial volume was measured using computed tomography image processing tools before the surgery, 24 hours after the surgery, and 1 month later. A mathematical model was developed to explain the clinical and surgical results. RESULTS: Five patients had secondary CCD and 4 had primary CCD. The mean age for cranial expansion was 16.78 years. The most frequent symptoms were headaches, nausea/vomiting, and decreased consciousness. Slit ventricles and sutural sclerosis were observed in 33.3% and 55.6% of patients. The mean ICP before the procedure was 48.67 mm Hg. Progressive cranial expansion was seen in all patients after surgery. The mean ICP decreased to 11 mm Hg and mean intracranial volume expansion was 85.8 cm3 at 1 month after surgery. There were no serious complications after surgery. All patients improved their symptoms, and no patient needed additional cranial expansion procedures. CONCLUSIONS: Chess-table cranial expansion is a safe and effective procedure and may be used as an alternative treatment for CCD. Progressive expansion of the intracranial volume is related to a decrease in ICP recordings and an improvement of symptoms.

Long-term reliability of the telemetric Neurovent-P-tel sensor: in vivo case report.

Intracranial pressure (ICP) measurements are imperative for the proper diagnosis and treatment of several neurological disorders. Telemetric sensors have shown their utility for ICP estimation in short-term monitoring in humans. However, their long-term reliability is uncertain. The authors present the case of a 37-year-old woman diagnosed with benign intracranial hypertension and obesity. The patient underwent gastric bypass surgery for ICP control. In order to monitor ICP before and after bariatric surgery, a Neurovent-P-tel sensor was implanted in the left frontal lobe. After gastric bypass, normal ICP values were recorded, and the patient's visual fields improved. However, the patient experienced incapacitating daily headaches. The authors decided to implant a Codman Microsensor ICP transducer in the right frontal lobe to assess the long-term reliability of the Neurovent-P-tel measurements. A comparison of the recordings at 24 and 48 hours showed good correlation and reliability during long-term monitoring with the Neurovent-P-tel, with minimal zero drift after 11 months of implantation.

Imaging biomarkers for steatohepatitis and fibrosis detection in non-alcoholic fatty liver disease.

There is a need, in NAFLD management, to develop non-invasive methods to detect steatohepatitis (NASH) and to predict advanced fibrosis stages. We evaluated a tool based on optical analysis of liver magnetic resonance images (MRI) as biomarkers for NASH and fibrosis detection by investigating patients with biopsy-proven NAFLD who underwent magnetic resonance (MR) protocols using 1.5T General Electric (GE) or Philips devices. Two imaging biomarkers (NASHMRI and FibroMRI) were developed, standardised and validated using area under the receiver operating characteristic curve (AUROC) analysis. The results indicated NASHMRI diagnostic accuracy for steatohepatitis detection was 0.83 (95% CI: 0.73-0.93) and FibroMRI diagnostic accuracy for significant fibrosis determination was 0.85 (95% CI: 0.77-0.94). These findings were independent of the MR system used. We conclude that optical analysis of MRI has high potential to define non-invasive imaging biomarkers for the detection of steatohepatitis (NASHMRI) and the prediction of significant fibrosis (FibroMRI) in NAFLD patients.