Continuous and entirely non-invasive method for cerebrovascular reactivity assessment: technique and implications

Continuous cerebrovascular reactivity assessment in traumatic brain injury (TBI) has been limited by the need for invasive monitoring of either cerebral physiology or arterial blood pressure (ABP). This restricts the application of continuous measures to the acute phase of care, typically in the intensive care unit. It remains unknown if ongoing impairment of cerebrovascular reactivity occurs in the subacute and long-term phase, and if it drives ongoing morbidity in TBI. We describe an entirely non-invasive method for continuous assessment of cerebrovascular reactivity. We describe the technique for entirely non-invasive continuous assessment of cerebrovascular reactivity utilizing near-infrared spectroscopy (NIRS) and robotic transcranial Doppler (rTCD) technology, with details provided for NIRS. Recent advances in continuous high-frequency non-invasive ABP measurement, combined with NIRS or rTCD, can be employed to derive continuous and entirely non-invasive cerebrovascular reactivity metrics. Such non-invasive measures can be obtained during any aspect of patient care post-TBI, and even during outpatient follow-up, avoiding classical intermittent techniques and costly neuroimaging based metrics obtained only at specialized centers. This combination of technology and signal analytic techniques creates avenues for future investigation of the long-term consequences of cerebrovascular reactivity, integrating high-frequency non-invasive cerebral physiology, neuroimaging, proteomics and clinical phenotype at various stages post-injury.

Debris disks around stars in the NIKA2 era

The new NIKA2 camera at the IRAM 30m radiotelescope was used to observe three known debris disks in order to constrain the SED of their dust emission in the millimeter wavelength domain. We have found that the spectral index between the two NIKA2 bands (1mm and 2mm) is consistent with the Rayleigh-Jeans regime (λ-2), unlike the steeper spectra (λ-3) measured in the submillimeter-wavelength domain for two of the three disks - around the stars Vega and HD107146. We provide a succesful proof of concept to model this spectral inversion in using two populations of dust grains, those smaller and those larger than a grain radius a0 of 0.5mm. This is obtained in breaking the slope of the size distribution and the functional form of the absorption coefficient of the standard model. The third disk - around the star HR8799 - does not exhibit this spectral inversion but is also the youngest.

NIKA2 mapping and cross-instrument SED extraction of extended sources with Scanamorphos

The steps taken to tailor to NIKA2 observations the Scanamorphos algorithm (initially developed to subtract low-frequency noise from Herschel on-the-fly observations) are described, focussing on the consequences of the different instrument architecture and observation strategy. The method, making the most extensive use of the redundancy built in the multi-scan coverage with large arrays of a given region of the sky, is applicable to extended sources, while the pipeline is so far optimized for compact sources. An example of application is given. A related tool to build consistent broadband SEDs from 60 microns to 2 mm, combining Herschel and NIKA2 data, has also been developed. Its main task is to process the data least affected by low-frequency noise and coverage limitations (i.e. the Herschel data) through the same transfer function as the NIKA2 data, simulating the same scan geometry and applying the same noise and atmospheric signal as extracted from the 1mm and 2mm data.

P1417 Acceptability of a virtual reality system for examination of congenital heart disease patients

Funding Acknowledgements

Work supported by the NIHR i4i funded 3D Heart project [II-LA-0716-20001]

Background/Introduction

Virtual Reality (VR) has recently gained great interest for examining 3D images from congenital heart disease (CHD) patients. Currently, 3D printed models of the heart may be used for particularly complex cases. These have been found to be intuitive and to positively impact clinical decision-making. Although positively received, such printed models must be segmented from the image data, generally only CT/MR may be used, the prints are static, and models do not allow for cropping / slicing or easy manipulation. Our VR system is designed to address these issues, as well as providing a simple interface compared to standard software. Building such a VR system, one with intuitive interaction which is clinically useful, requires studying user acceptance and requirements.

Purpose: We evaluate the usability of our VR system

can a prototype VR system be easily learned and used by clinicians unfamiliar with VR.

Method

We tested a VR system which can display 3D echo images and enables the user to interact with them, for instance by translating, rotating and cropping. Our system is tested on a transoesophageal echocardiogram from a patient with aortic valve disease. 13 clinicians evaluated the system including 5 imaging cardiologists, 5 physiologists, 2 surgeons and an interventionist, with their clinical experience ranging from trainee to more than 5 years’ of experience. None had used VR regularly in the past. After a brief training session, they were asked to place three anatomical landmarks and identify a particular cardiac view. They then completed a questionnaire on system ease of learning and image manipulation.

Results: Results are shown in the figure below. Learning to use the system was perceived as easy for all but one participant, who rated it as ‘Somewhat difficult’. However, once trained, all users found the system easy to use. Participants found the interaction, where objects in the scene are picked up using the controller and then track the controller’s motion in a 1:1 way, to be particularly easy to learn and use.

Conclusion

Our VR system was accepted by the vast majority of clinicians, both for ease of learning and use. Intuitiveness and the ability to interact with images in a natural way were highlighted as most useful - suggesting that such a system could become accepted for routine clinical use in the future.

Abstract P1417 Figure. VR system evaluation participant feedbac

The NIKA polarimeter on science targets: Crab nebula observations at 150 GHz and dual-band polarization images of Orion Molecular Cloud OMC-1

We present here the polarization system of the NIKA camera and give a summary of the main results obtained and performed studies on Orion and the Crab nebula. The polarization system was equipped with a room temperature continuously rotating multi-mesh half wave plate and a grid polarizer facing the NIKA cryostat window. NIKA even though less sensitive than NIKA2 had polarization capability in both 1 and 2 millimiter bands. NIKA polarization observations demonstrated the ability of such a technology in detecting the polarization of different targets, compact and extended sources like the Crab nebula and Orion Molecular Cloud region OMC-1. These measurements together with the developed techniques to deal with systematics, opened the way to the current observations of NIKA2 in polarization that will provide important advances in the studies of galactic and extra-galactic emission and magnetic fields.

P801 A virtual reality tool for measurement of 3D echocardiographic images

Funding Acknowledgements

Work supported by the NIHR i4i funded 3D Heart project [II-LA-0716-20001]

Background/Introduction

Cardiac measurements are clinically important and are invariably required in any clinical imaging software. The advent of Virtual Reality (VR) imaging systems is introducing intuitive and natural ways of visualising and interrogating echo images in a 3D environment. The 3D nature of the VR experience requires purpose-designed measurement tools, which may benefit from better depth perception and easier localisation of 3D landmarks.

Purpose

Comparison of the accuracy of our VR 3D linear measurement system to commercial clinical imaging software, using both multi-plane reformatting (MPR) and volume rendered views.

Method

Each virtual reality measurement was made by selecting two points in 3D, directly in the volume rendering. The participants could edit the measurements until satisfied with their accuracy. 5 expert clinicians carried out 26 measurements each - 6 measurements on a calibration phantom, and 5 anatomically meaningful measurements (for example: aortic valve, left atrium, left ventricle) on 4 datasets. The same measurements were made by all participants using our VR system (volume rendering), Philips" QLAB (MPR) and Tomtec (volume rendering). The frame number and view (for example: long axis) were consistent for each measurement across the 3 packages used.

Results

Preliminary results are shown in the figure below. MPR measurements made on Philips’ QLAB are used as a reference, as this is the most commonly used software for this purpose at our institution. We compare measurements made in Tomtec and VR, both using volume rendering, using Bland-Altman plots. Each measurement data point is the mean of all participants measurements for each dataset/measurement combination. The mean of the measurement differences for the VR system is closer to zero, compared to Tomtec. However, the variation of these differences is larger for the VR system than for Tomtec.

Conclusion

Our preliminary results suggest that the accuracy of line measurements made using volume rendering within a VR system is comparable to measurements made using approved software packages for volume rendering displayed on a 2D screen. This shows promise for more complex interrogation methods.

Abstract P801 Figure. Comparison of Tomtec and VR with QLAB

NIKA: a mm camera for Sunyaev-Zel’dovich science in clusters of galaxies

Clusters of galaxies, the largest bound objects in the Universe, constitute a cosmological probe of choice, which is sensitive to both dark matter and dark energy. Within this framework, the Sunyaev-Zel’dovich (SZ) effect has opened a new window for the detection of clusters of galaxies and for the characterization of their physical properties such as mass, pressure and temperature. NIKA, a KID-based dual band camera installed at the IRAM 30-m telescope, was particularly well adapted in terms of frequency, angular resolution, field-of-view and sensitivity, for the mapping of the thermal and kinetic SZ effect in high-redshift clusters. In this paper, we present the NIKA cluster sample and a review of the main results obtained via the measurement of the SZ effect on those clusters: reconstruction of the cluster radial pressure profile, mass, temperature and velocity.

A low-mass galaxy cluster as a test-case study for the NIKA2 SZ Large Program

High-resolution mapping of the hot gas in galaxy clusters is a key tool for cluster-based cosmological analyses. Taking advantage of the NIKA2 millimeter camera operated at the IRAM 30-m telescope, the NIKA2 SZ Large Program seeks to get a high-resolution follow-up of 45 galaxy clusters covering a wide mass range at high redshift in order to re-calibrate some of the tools needed for the cosmological exploitation of SZ surveys. We present the second cluster analysis of this program, targeting one of the faintest sources of the sample in order to tackle the difficulties in data reduction for such faint, low-SNR clusters. In this study, the main challenge is the precise estimation of the contamination by sub-millimetric point sources, which greatly affects the tSZ map of the cluster. We account for this contamination by performing a joint fit of the SZ signal and of the flux density of the compact sources. A prior knowledge of these fluxes is given by the adjustment of the SED of each source using data from both NIKA2 and the Herschel satellite. The first results are very promising and demonstrate the possibility to estimate thermodynamic properties with NIKA2, even in a compact cluster heavily contaminated by point sources.

Topologically protected superconducting ratchet effect generated by spin-ice nanomagnets

We have designed, fabricated and tested a robust superconducting ratchet device based on topologically frustrated spin ice nanomagnets. The device is made of a magnetic Co honeycomb array embedded in a superconducting Nb film. This device is based on three simple mechanisms: (i) the topology of the Co honeycomb array frustrates in-plane magnetic configurations in the array yielding a distribution of magnetic charges which can be ordered or disordered with in-plane magnetic fields, following spin ice rules; (ii) the local vertex magnetization, which consists of a magnetic half vortex with two charged magnetic Néel walls; (iii) the interaction between superconducting vortices and the asymmetric potentials provided by the Néel walls. The combination of these elements leads to a superconducting ratchet effect. Thus, superconducting vortices driven by alternating forces and moving on magnetic half vortices generate a unidirectional net vortex flow. This ratchet effect is independent of the distribution of magnetic charges in the array.

[Medical thoracoscopy in respiratory medicine: The Liège University Hospital experience]

INTRODUCTION

The incidence of pleural disease continues to increase worldwide. Medical thoracoscopy remains the standard method for exploration of the pleural cavity.

METHOD

We report the retrospective evaluation, the efficacy and the observed complications in 1024 medical thoracoscopies undertaken in the University Hospital of Liège between 2000 and 2017.

RESULTS

In total, 100 pneumothoraces and 400 benign and 501 malignant pleural diseases were identified. The main indication for thoracoscopy remains the diagnosis of an exudative, lymphocytic pleural effusion of unknown aetiology after thoracocentesis. The diagnostic sensibility of thoracoscopy was 99.2% in distinguishing benign from malignant pleural disease. Talc pleurodesis was performed in 69.5% of the total population and in 66.1% of pleural effusions or thickening. Failure of pleurodesis was observed in 11% of the patients with recurrent pneumothorax and in 7.8% of neoplastic pleural effusion. We report a mortality of 0.6% in the 30 days post procedure, long duration of drainage in 8.3% and serious complications in 4.7%. In 22/1024 (2.1%) thoracoscopic evaluation was not feasible because of dense pleural fibrosis.

CONCLUSION

Medical thoracoscopy is a safe, well-tolerated procedure with high accuracy in the diagnostic and therapeutic management of pleural disease.

The unique composition of Indian gut microbiome, gene catalogue, and associated fecal metabolome deciphered using multi-omics approaches

BACKGROUND

Metagenomic studies carried out in the past decade have led to an enhanced understanding of the gut microbiome in human health; however, the Indian gut microbiome has not been well explored. We analyzed the gut microbiome of 110 healthy individuals from two distinct locations (North-Central and Southern) in India using multi-omics approaches, including 16S rRNA gene amplicon sequencing, whole-genome shotgun metagenomic sequencing, and metabolomic profiling of fecal and serum samples.

RESULTS

The gene catalogue established in this study emphasizes the uniqueness of the Indian gut microbiome in comparison to other populations. The gut microbiome of the cohort from North-Central India, which was primarily consuming a plant-based diet, was found to be associated with Prevotella and also showed an enrichment of branched chain amino acid (BCAA) and lipopolysaccharide biosynthesis pathways. In contrast, the gut microbiome of the cohort from Southern India, which was consuming an omnivorous diet, showed associations with Bacteroides, Ruminococcus, and Faecalibacterium and had an enrichment of short chain fatty acid biosynthesis pathway and BCAA transporters. This corroborated well with the metabolomics results, which showed higher concentration of BCAAs in the serum metabolome of the North-Central cohort and an association with Prevotella. In contrast, the concentration of BCAAs was found to be higher in the fecal metabolome of the Southern-India cohort and showed a positive correlation with the higher abundance of BCAA transporters.

CONCLUSIONS

The study reveals the unique composition of the Indian gut microbiome, establishes the Indian gut microbial gene catalogue, and compares it with the gut microbiome of other populations. The functional associations revealed using metagenomic and metabolomic approaches provide novel insights on the gut-microbe-metabolic axis, which will be useful for future epidemiological and translational researches.

Abstract P4-08-07: Discordance between surrogated intrinsic subtypes defined by immunohistochemistry compared with PAM50 in ER positive / HER2 negative early breast cancer. Analysis of value of the status of the progesterone receptor and Ki67

Introduction: Classification by intrinsic subtypes by gene expression profiles of early-stage breast cancer (EBC) provides information of prognostic value and constitutes a tool to help in making therapeutic decisions. Several authors have proposed surrogated classifications based on immunohistochemistry results (IHC) in order to facilitate a classification with identical prognostic and predictive value. However, there is evidence that suggests a lack of correlation between these classifications.

The aim of this study was to evaluate the correlation between classification by intrinsic subtypes in patients with EBC ER+/ HER2neg, obtained by PAM50 and the surrogated classification proposed by St. Gallen 2013.

Methods: Samples from 12 centers from the spanish region of Castilla y León were analyzed by PAM50 (nCounterTM / Nanostring) at the University Hospital of Salamanca. The results obtained were compared with the surrogate classification of St.Gallen'13 from local reports. Tumors of patients pre and post-menopausal tests T1-2, N0-N1mi, grade I-II that met criteria for inclusion of the regional evaluation program through ProsignaTM were included.

Results: Between August'15 and December'17, 264 samples were analyzed. All patients were classified by IHC as lum-A or lum-B. In total 113 cases were reclassified by PAM50 (43%). The change of LumA by IHC to Lum-B by PAM50 was 18%, while Lum-B by IHC to Lum-A by PAM50 was 58% (n = 89). In those cases considered Lum-B by IHC based only in a value of Ki67>14% (n = 93), 54% was reclassified to Lum-A. Conversely, when low expression (negative or <20%) of Progesterone Receptor (PR) was used as the single criterion of Lum-B by IHC (n = 44), PAM50 reclassified 33 cases as Lum-A (75%). Applying the Kappa test to analyze the concordance between the 2 tests, a coefficient of 0.203 (low agreement) was obtained, statistically significant (0.000).

Conclusion: The surrogated classification by IHC of intrinsic subtypes in EBC ER+/HER2neg shows a low concordance with PAM50 analysis, and cannot be considered adequate. In particular, the presence of negative or <20% PR as the only criterion seems the least appropriate and should not be recommended for a surrogated classification of a tumor as Lum-B, overestimating the real risk of numerous patients. PAM50 allowed the reclassification in more than 40% of cases, especially csaes considered Lum-B by IHC.

Citation Format: Rodriguez CA, Guillen C, Garcia M, Sancho M, Gomez A, Ludena D, Cruz JJ. Discordance between surrogated intrinsic subtypes defined by immunohistochemistry compared with PAM50 in ER positive / HER2 negative early breast cancer. Analysis of value of the status of the progesterone receptor and Ki67 [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-08-07.

Pediatric acute respiratory distress syndrome associated with human metapneumovirus and respiratory syncytial virus

OBJECTIVES

To study the incidence, risk factors, clinical course, and outcome of ARDS in children with HMP and RSV.

WORKING HYPOTHESIS

We hypothesized that ARDS in children with HMP was similar in incidence, risk factors, clinical course, and outcomes to ARDS in children with RSV.

STUDY DESIGN

Retrospective, observational study over 2 years.

PATIENT-SUBJECT SELECTION

Patients included were <18 years old with HMP or RSV detected from nasopharyngeal specimens by commercial reverse transcriptase polymerase chain reaction assay admitted to a study site.

METHODOLOGY

We described the incidence of ARDS within 1 week following the detection of HMP or RSV using recently developed Pediatric ARDS (PARDS) criteria. We also assessed risk factors, clinical course, and outcomes of children in the PICU with HMP or RSV and PARDS or non-PARDS.

RESULTS

We identified 57 patients with HMP and 161 patients with RSV: the proportions of patients with either virus who developed PARDS (HMP: 23%, RSV: 20%) and severe PARDS (HMP: 9%, RSV: 7%) were similar, as were the proportions of patients with acute (or acute-on-chronic) respiratory failure who developed PARDS (HMP: 41%, RSV: 31%). In a logistic regression model, risk factors associated with PARDS included neurologic comorbidity and PIM 3 probability of mortality, but not virus type. The risk factors, clinical course, and outcomes were similar for patients with PARDS associated with HMP and RSV.

CONCLUSIONS

About 1/3 of children with HMP or RSV and acute (or acute-on-chronic) respiratory failure developed PARDS. Children with either virus and a neurologic comorbidity or an increased PIM 3 probability of mortality were at increased risk for PARDS.

The high-energy x-ray diffraction and scattering beamline at the Canadian Light Source

The optical design for the high-energy x-ray diffraction and scattering beamline of the Brockhouse sector at the Canadian Light Source is described. The design is based on a single side-bounce silicon focusing monochromator that steers the central part of a high-field permanent magnet wiggler beam into the experimental station. Two different configurations are proposed: a higher energy resolution with vertical focusing and a lower energy resolution with horizontal and vertical focusing. The monochromator will have the possibility of mounting three crystals: one crystal optimized for 35 keV that focuses in the horizontal and vertical directions using reflection (1,1,1) and two other crystals both covering the energies above 40 keV: one with only vertical focusing and another one with horizontal and vertical focusing. The geometry of the last two monochromator crystals was optimized to use reflections (4,2,2) and (5,3,3) to cover the broad energy range from 40 to 95 keV.

Serum CEA, CA125, and SCC antigens and tumor recurrence in resectable non-small cell lung cancer

Carcinoembryonic antigen (CEA), squamous cell carcinoma antigen (SCC), and CA125 were determined pre- and postoperatively in non-small cell lung cancer patients (NSCLC) to assess the relationship between serum levels and postoperative recurrent disease. Ninety-five patients who underwent curative surgical resection were included (TNM stages I, II, IIIa). CEA and CA125 were determined by solid-phase enzyme-immunoassay, SCC by radio-immunoassay. Tumor relapse was detected in 41 patients (43%): 16 (39%) with locoregional disease and 25 (61%) with disseminated disease. The overall 36-month disease-free survival rate was 42%. The sensitivity for recurrence was 58% for CEA, 53.6% for CA125, and 51.2% for SCC; 87.8% of patients showed at least one elevated marker. The sensitivity of CEA and CA125 increased significantly in patients with preoperative serum concentrations above the cut-off: 86.6% versus 42.3% (p < 0.01), and 93% versus 18% (p < 0.01), respectively. Preoperative CA125 above 15 U/ml identified a high-risk group of patients: a lower 36-month disease-free survival rate (0%) versus 56%) (p < 0.001), a 3.02-fold higher risk of recurrence (p < 0.05), and a 6.22-fold higher risk of disseminated failure (p < 0.001). The identification of CEA and CA125 producer-tumors, based on preoperative serum values, enhances the clinical performance of a postoperative surveillance program in surgically treated NSCLC. Preoperative serum CA125 is a prognostic factor to identify patients at high risk of postoperative tumor recurrence.

Evaluation of the sensitivity of RAS mutation detection of the Idylla platform in comparison to the OncoBEAM RAS CRC assay

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Background: Accurate detection of RAS mutations in metastatic colorectal cancer (mCRC) patients is of high clinical importance for therapy selection as RAS detection methods lacking sensitivity may lead to poor patient outcomes. Liquid biopsy has emerged as a viable alternative to individualize the management and treatment of mCRC patients. However, there is a current need to cross-compare the performance of liquid biopsy platforms. The OncoBEAM RAS dPCR assay offers highly sensitive RAS mutation detection in clinical practice, achieving > 90% concordance when compared to results obtained by tumor mutation testing. The Idylla platform offers a highly-automated qPCR platform for RAS mutation testing of tissue samples, and has shown potential for liquid biopsy. The objective of this study was to provide a head-to-head comparison of the sensitivity of OncoBEAM and Idylla for KRAS mutation detection in plasma from mCRC patients. Methods: Plasma samples from 92 mCRC patients determined to be KRAS-positive using OncoBEAM were re-tested using Idylla. Samples with mutant allelic fractions (MAF) below 5% were selected for analysis. The positive percent agreement (PPA) of KRAS mutation results was compared for replicate samples analyzed by OncoBEAM and Idylla. Results: So far, Idylla detected KRAS mutations in 63 out of 92 (68.4%) OncoBEAM KRAS-positive plasma samples. Categorization of results based on MAF% revealed distinct differences in sensitivity between the two technologies. Conclusions: OncoBEAM demonstrated significantly greater sensitivity for plasma detection of RAS mutations than Idylla. Moreover, these data identify a “gray zone” below 1% MAF where Idylla fails to identify RAS-positivity in patient plasma samples. These findings serve as a reminder that liquid biopsy assays with diminished sensitivity may lack the dynamic range to provide accurate and timely RAS mutational status information to properly guide highly individualized anti-EGFR therapy and chemotherapy treatment decisions that may benefit patient outcomes. [Table: see text]