A method of measuring transmittance of radiation from the film of ice 0 in the IR wave band deposited on a dielectric plate

A method of measuring transmittance of radiation from the film of ice 0 in the infrared wave band is described. Ice 0 is formed from supercooled water at the temperature below –23°C. This ice is ferroelectric and forms a highly conductive layer of the nanometric order of thickness at the boundary with dielectric. The complexity of the experiment consisted in the necessity of using low intensities of the probing signal and considering radiation of the cooled parts of the installation. In order to obtain a thin film of ice, the method of depositing water vapor on a substrate cooled in nitrogen was used. The method rules out formation of condensate in cooling. Deposition of water vapor is possible only in heating, when delivery of cold nitrogen vapor into the chamber with the sample is excluded. To ensure exposure of the film to IR radiation, two sources of infrared radiation were considered: a halogen lamp with a broad radiation spectrum (on the surface of heated glass) and a CO2 laser with the radiation wavelength of 10.6 µm. In the first case, spectral measurements are possible when filters are used. In the installation based on a CO2 laser, an intense signal is emitted, requiring consideration of sample heating. Components of the installation have been elaborated and investigated, on which transmittance of radiation from the film of ice 0 is planned to be measured.

Clinical and Neuroimaging Changes of Subacute Sclerosing Panencephalitis – Experience 30 Cases in Tertiary Care Center in Bangladesh

Background: Subacute sclersing panencephalitis (SSPE) is a very rare progressive, fatal neurodegenerative disease of the control nervous system of childhood and early adolescence. It is a slow virus disease caused by persistent defective measles virus infection of the brain Objective: To see the clinical andneuro-imaging findings in children with Subacute sclerosing panencephalitis. Methods: This retrospective study was conducted at Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, a tertiary care premier Postgraduate Medical Institution in Bangladesh. Thirty (30) Subacute sclerosing panencephalitis (SSPE) children were evaluated at paediatric neurology ward during the period January 2010 to December 2017. Diagnosis was based on typical clinical characteristic features, the presence of periodic discharges on EEG, demonstration of raised antibody titer against measles in the plasma and cerebrospinal fluid Detected by ELISA in all patients. Results: Total number of studied children were 30. Mean age was 10.2±3.1 year and Male female ratio was 5:1. Most of the patient arrived from poor socio-economic (83.33%) background of rural area (66.67%) of Bangladesh. Among them 46.67% had history of measles infection during early childhood. Progressive deterioration of school performance (50%), gait disturbance (70%), myoclonus (83%) dysarthria (43%) and Ocular manifestations like optic atrophy & papilledema (83.33%) were the main presenting feature of our studied children. All of the patients (100%) showed positive measles specific antibody IgG in CSF and On electroencephalographic findings showed periodic burst suppression in 90.90% cases. Most of the children (56.6%) were in stage II category and other 3.3%, 33.3%,6.6%, were stage I, stage III, stage IV category respectively. Neuroimaging study showed abnormalities in 45.83% cases included periventricular white matter hyper intense signal changes, cortical atrophy and ischaemic change. Conclusion: In our study most of the SSPE patient were in stage II.About half of the patient had history of measles infection during early childhood. Neuroimaging abnormalities found in about half of the cases and majority cases were in stage II. Common neuroimaging abnormalities were periventricular white matter hyper intense signal changes and cortical atrophy.

POS1160 BRUCELLAR SPONDYLODISCITIS: CLINICAL AND MAGNETIC RESONANCE IMAGING FINDINGS

Background:Osteoarticular involvement is one of the most common complications of brucellosis and it can occur in up to two thirds of patients infected. Vertebral involvement during brucellosis is considered not only as the most prevalent localization but also as the most severe one.Objectives:The aim of the present study was to describe the clinical and the magnetic resonance imaging features of brucellar spondylodiscitis.Methods:We conducted a retrospective study including 21 patients who have been hospitalized for spinal brucellosis from 1998 to 2019. The diagnosis of brucellosis was based on clinical symptoms, MRI findings and isolation of brucella species in blood or tissue specimens and/or a positive Wright agglutination test.Results:Twenty-one patients were included. The mean age was 57.5 years [33-74] (13 males and 8 female). The geographical origin of the patients was rural in 76% of the cases. The median duration of symptoms progression before diagnosis was 4.5 months [1-8].The main symptom leading to seek medical care was an inflammatory back pain and it was found in all cases. It was associated with unilateral radiculopathy in 8 cases and with a bilateral radiculopathy in 1 case. The other clinical features found were fever in 17 patients, sweats in 14 cases, weight loss in 10 cases and hepatomegaly in 1 patient. The physical examination revealed tenderness on palpation in 12 cases, a motor weakness of the two lower limbs in 2 cases. Brucella agglutination test was ≥1/160 in all cases. Blood cultures were negative in all cases. The median erythrocyte sedimentation rate (ESR) and serum C-reactive protein level were 40 mm and 11mg/dl) respectively. Spondylodiscitis was located in the lumbar dorsal and cervical spine in respectively 10, 8 and 3 cases. The most affected level was the L4-L5 level in 5 cases followed by the T10-T11 level in 3 cases. The involvement of more than 2 vertebrae was found in 4 cases. Associated sacroiliitis was found in one patient. All MRI images of the affected vertebrae showed hypo intense signal on T1 weighted image and hyper intense signal on T2 weighted image. Disc space narrowing was found in 8 cases. Vertebral body osteolysis was found in 10 cases. Epidural collection was documented in 3 cases with a size up to 5cm. Paravertebral and peri-vertebral abscesses were detected in 5 cases. Intradiscal abscesses were observed in 3 cases. Cord compression and involvement of root nerve were noted in respectively 5 and 1 cases. Biopsy was performed in 5 cases, but bacteriological examination was contributory to the diagnosis in 1 case. All patients received antibiotic treatment with a combination of two or three drugs, corticosteroids were prescribed in 5 patients and one patient underwent a surgical intervention. The evolution was good 16 in patients, three patients suffered from chronic back pain, one patient had persistent neuropathic pain and one patient had paresis.Conclusion:Brucella spondylodicitis is still a serious public health problem in developing countries. MRI findings associated with clinical symptoms may establish the diagnosis even if bacteriological examinations are negativesDisclosure of Interests:None declared.

Fragmentation study of tryptophan-derived metabolites induced by electrospray ionization mass spectrometry for highly sensitive analysis

ESI of tryptophan-derived metabolites produced an intense signal of fragment ion with a spiro[cyclopropane-indolium] backbone. The use of corresponding fragment ions for the precursor of MRM transitions could improve the detection limit.

White matter: A good reference for the signal intensity evaluation in magnetic resonance imaging for the diagnosis of uveal melanoma

Background Comparing the signal intensity (SI) of an ocular mass to that of the vitreous body has been suggested. Most ocular lesions show a hyper-intense signal compared to the vitreous body on T1-weighted (T1w) images, and malignant melanomas have been almost always determined as ‘cannot be excluded’ in reports. Purpose This study aimed to determine the accuracy of magnetic resonance imaging (MRI) in the diagnosis of uveal melanoma by using normal white matter as reference tissue for SI evaluation on T1w images and vitreous body on T2w compared to the conventional method using the vitreous body as a reference on both T1w and T2w images. Methods The MRIs of 43 patients (between August 2006 and July 2018) sent to rule out uveal melanoma were blindly reviewed by two radiologists. By using white matter as a reference for SI evaluation on T1w images and vitreous body as a reference on T2w images, uveal melanomas were suggested by hyper-intense signal on T1w and hypo-intense signal on T2w with homogeneous enhancement. The accuracy of diagnosis of uveal melanoma using white matter as a reference on T1w was compared to the conventional method using the vitreous body as a reference on both T1w and T2w images. Results The diagnosis of uveal melanoma using white matter as a reference gave a sensitivity of 92.31% (95% confidence interval (CI) 63.97–99.81) and specificity of 100.0% (95% CI 88.43–100.0). By using the vitreous body as a reference, sensitivity as high as 100.0% (95% CI 100.0–100.0) was obtained, but specificity was low at 53.33% (95% CI 34.33–71.66). Conclusions White matter is a good reference for the diagnosis of uveal melanoma, with high sensitivity and much higher specificity than conventional methods using the vitreous body as a reference.

P951 Intraprocedural echocardiographic technique to locate the insertion points of artificial chordae during transventricular beating heart mitral valve repair: ultrasound ""starry sky""

BACKGROUND Mitral valve repair is the preferred surgical treatment for severe mitral regurgitation due to degenerative leaflet prolapse. Within the growing era of transcatheter treatments for valvular heart disease, an innovative micro-invasive trans-ventricular beating-heart procedure was developed. Three-dimensional transoesophageal echocardiographic guidance is crucial to assist the operator in instrument navigation and chords positioning. Indeed, it is important an equidistant chords placement on the leaflet to ensure a uniform force distribution on the prolapsing segment and to avoid damaging of the previously inserted chords. PURPOSE To propose an intraoperative three-dimensional echocardiographic technique that allows operators to see the exact location of the polytetrafluoroethylene (ePTFE) chords used for the mitral repair. METHODS The procedure is performed using a device that is introduced through a posterolateral ventriculotomy and it is advanced towards the mitral valve under real-time 3D transoesophageal guidance. The prolapsing segments are grasped with the jaw of the instrument and the chords are implanted to achieve the proper distribution of forces and then tensioned and secured outside the ventricle. The proposed technique exploits the greater echogenicity of the artificial chord loop compared to native chords and leaflets. By lowering of the gains, remaining in the three-dimensional mitral valve surgical view, the signals of the native structures are attenuated, the underlying ventricular cavity appears black and the insertion points are visible as an intense signal on the virtual free edge of the leaflet treated. Figure 1 shows the intraoperative sequence of images of a case performed at our centre. The images were acquired using real time single beat three-dimensional reconstruction. Figure 1A shows the surgical view of the native valve with prolapse of the P2-P3 scallops. Image 1B reveals the prolapsing leaflet grasping and device location. After gain lowering, it’s possible to see the intense signal of the positioned artificial chord (Figure 1C). It can also be noted how this position matches with the position of the device at the time of grasping. Image 1D shows the partial disappearance of the prolapse during the tensioning test after the positioning of a second chord in a more medial position. Figure 1E shows the correct position of the ePTFE chords. We can notice the second chord placed in a medial position from the first one. This view, with dark ventricular chamber and intense signals of chordae loops, looks like a "STARRY SKY". RESULTS This technique allows to locate the correct insertion points of the artificial chords during the procedure. CONCLUSIONS This is a simple technique to guide operators during trans-ventricular beating heart mitral valve repair with ePTFE chords. Abstract P951 Figure 1

NIMG-59. ADVERSE EFFECTS OF IMAGE TILING FOR AUTOMATIC DEEP LEARNING GLIOMA SEGMENTATION IN MRI

BACKGROUND Application of deep learning to neuro-oncology has shown promising clinically relevant results for tumor classification, localization, and segmentation. Hardware limitations, typically memory size of graphics cards, prevent magnetic resonance imaging (MRI) volumes from being processed as a whole, and hence they are divided into smaller, overlapping tiles. Deep learning algorithms (e.g., U-Net) can then be trained and applied for predictions on such tiles, followed by their combination/stitching as the final prediction for the whole volume. We investigate the hypothesis that image tiling options, such as tile placing, size, overlap, and stitching, introduce variations with adverse effects on predictions, both in terms of inconsistency and accuracy. METHODS We utilized the publicly available BraTS 2018 dataset of 285 baseline pre-operative MRI glioma scans, with corresponding expert tumor boundary annotations. We implemented a 3D U-Net to predict boundaries of the whole tumor extent, by virtue of the abnormal hyper-intense signal of T2-FLAIR scans. RESULTS Simply flipping the tile horizontally, or translating it by one voxel, produces different predictions. Use of small tiles (64x64x64 voxels) yields substantially more false positive predictions than when using larger tile size (i.e., 128x128x128 voxels). Overlapping tiles produce conflicting predictions, leading to ambiguous interpretations upon their stitching. In areas of overlapping tiles, rounding followed by averaging the overlapping predictions produce superior results to the inverse sequence. All these are particularly noticeable in the margins of the abnormal signal and in areas of large contrast variation. CONCLUSIONS Although tiling is a workaround for hardware limitations, it introduces variations detrimental to accuracy. Tiling of neuro-oncology scans for computational analysis using deep learning leads to non-generalizable, non-reproducible results, thereby affecting the performance and potential clinical translatability of such algorithms. Careful considerations and standardization recommendations should be established and appropriately documented for performing such analyses, in order to avoid misinterpretation of results.

On the selection of endogenous and exogenous signals

Alerting is one of the three components of attention which involves the eliciting and maintenance of arousal. A seminal study by Posner et al. (Posner MI, Klein R, Summers J, Buggie S. 1973 Mem. Cognit. 1 , 2–12 ( doi:10.3758/BF03198062 )) focused on how changing the interval between an alerting signal and a target would impact the speed and accuracy of responding. Participants indicated whether targets were presented on the left or right side of the fixation point. Auditory warning signals were played at various intervals prior to the target to alert participants and prepare them to make a response. Reaction times revealed a robust, U-shaped, preparation function. Importantly, a clear speed-accuracy trade-off (SAT) was observed. In the current experiment, we replicated the methodological components of this seminal study while implementing a novel auditory warning signal (Lawrence MA, Klein RM. 2013 J. Exp. Psychol. General 142 , 560 ( doi:10.1037/a0029023 )) that was either purely endogenous (change in quality without a change in intensity; analogous to isoluminant colour change in vision) or a combination of endogenous and exogenous (change in both quality and intensity). We expected to replicate the U-shaped preparation function and SAT observed by Posner and colleagues. Based on Lawrence and Klein's findings we also expected the SAT to be more robust with the intense signal in comparison to the isointense signal.

Raman spectroscopy of nanograins, nanosheets and nanorods of copper oxides obtained by anodization technique.

Different nanostructures such as: CuOH nanorods, CuO nanosheets and Cu2O nanograins were obtained by anodization approach at room temperature during times from 10 to 40 minutes. By scanning electron microscopy technique, it was found that Cu2O nanograins were formed at 10 minutes, CuO nanosheets vertically oriented on nanograins were observed at 20 and 30 minutes, and from 20 minutes CuOH nanorods with low vertical orientation on nanosheets were formed, coexisting the three types of nanostructures at the same system. In samples without thermal treatment were observed that Raman spectra of nanograins have a typical signal at 218 cm-1 associated to Cu2O, Raman spectra of nanosheets have signals at 287 and 630 cm-1 associated to CuO and Raman spectra of nanorods, it was observed that Raman spectrum is dominated by an intense signal associated to CuOH located around 488cm-1. In addition, after 3 hours of thermal treatment at 300 °C, the morphology was conserved, and the hydrogen-related compound decreased. Raman spectra of nanorods only presented a signal at 287 cm-1 associated to CuO whereas in nanosheets three peaks at 150, 218, 304 cm-1 associated to the Cu2O were observed.