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Aims and Objective: To study the comparison of oxygen saturation values in supine and sitting position above 60 year old patients. Background: Changes in posture affect ventilation-perfusion rates, O2 transport and lungs volume in normal lungs. Study Design: An observational study. Methods: A preoperative observational study was conducted after the clearance from institutional ethical committee on 60 patients in department of Anaesthesiology, M.M.I.M.S.R, Mullana, Ambala Haryana, India. A sample of 60 elderly individuals with no heart disease, bleeding disorder, pain or anemia was included in the research. Individuals were positioned in two positions-supine and sitting. Oxygen saturation and pulse rates were then measured and recorded after the individuals held each position for ten minutes. Results: It was found that the average SpO2 value when measured while sitting in a chair was significantly higher than that measured when the individual was in supine body position. Hence, elderly patients, especially who have diminished cardio respiratory reserve, should be preferably made to sit rather than put in supine position for better vitals. Conclusion: This study was conducted to analyze differences in hemodynamics viz-a-viz oxygen saturation levels, pulse rate between supine and sitting position. It was found that saturation levels were higher in patients made to sit rather than those in supine position. [ABSTRACT FROM AUTHOR]

Optical orthogonal frequency-division multiplexing (OOFDM) has recently been proposed and the proof-of-concept transmission experiments have shown its extreme robustness against chromatic dispersion and polarization mode dispersion. In this paper Signal pre-distortion method is proposed to mitigate nonlinear effect from vertical-cavity surface-emitting laser (VCSEL) optical system. We then evaluate the value of relative intensity to noise (RIN) for its optimum performance. [ABSTRACT FROM AUTHOR]

High-resolution ultrasound is now the imaging modality of choice for the assessment of a vast majority of palpable swellings in the head and neck. In experienced hands, it is frequently the only imaging technique required for diagnosis since it can be performed rapidly, safely and permits accurate tissue sampling. A systematic approach to the sonographic assessment of neck lumps is provided with practical advice including tips and pitfalls on scanning and fine needle aspiration technique. Reflecting the cumulative experience using sonography within a busy Quick Early Diagnosis clinic for patients with suspected head and neck cancer, emphasis is placed on the evaluation of the entire neck including nodal drainage sites, meticulous assessment of lymph nodes to identify often subtle features indicative of abnormality, appreciation of typical features of common non-nodal pathologies, and recognition of normal structures commonly mimicking neck lumps. In practice, additional imaging techniques including CT and MRI are not routinely required, and indications for these are outlined. [ABSTRACT FROM AUTHOR]

Although previous studies have documented correlations between pretreatment or post-treatment primary tumour volumes and local outcome following definitive concomitant chemoradiotherapy (CCRT) in head and neck squamous cell carcinoma (HNSCC), no study has included and compared tumour volumes during CCRT. We reviewed the MRIs of 69 HNSCC patients treated with a 6 weeks course of CCRT and who underwent successful MRI pre-treatment (n569), 2 weeks intra-treatment (n548) and 6 weeks post-treatment (n561). Primary tumour volumes on MRI at the three time points were calculated and compared for their predictive value for primary site outcome. Volume thresholds optimised to predict failure with the highest accuracy and positive predictive value (PPV) were calculated. The mean pre-treatment volume was 24.6 cm3 (range, 1.1-187.9 cm3) and the mean follow-up interval was 41 months (range, 12-100 months). 23 primary tumours failed treatment (33%). Volumes before, during and after CCRT were positively associatedwith local failure (p50.015, p50.009, p,0.0001). Volume reductions during and after CCRT were negatively associated with local failure (p50.021, p50.001). Pre-treatment and intra-treatment volume thresholds achieved the highest accuracy and produced intermediate PPVs (51-64%) for predicting local failure. Optimised intra-treatment thresholds did not identify any more treatment failures than the pre-treatment thresholds. By comparison, a 6 weeks post-treatment volume reduction (,35%) achieved 100% PPV for failure, albeit with 26% sensitivity. In conclusion, primary tumour volumetry performed early in CCRT provides minimal additional information compared with pre-treatment volumetry, with respect to predicting post-treatment local failures. Therefore, volumetry during CCRT is unlikely to be useful for guiding individual response-based therapeutic modifications. [ABSTRACT FROM AUTHOR]

The utility of diffusion-weighted imaging (DWI) in the detection of squamous cell carcinoma (SCC) of the tonsils has not been previously investigated. This preliminary study compared DWI of apparent SCC tonsillar tumours with normal tonsils. DWI of the tonsils was performed in 10 patients with newly diagnosed tonsil SCC that was evident on conventional MRI and in 17 patients undergoing cranial MRI for other indications. Regions of interest (ROI) were drawn around each identifiable tonsil on the apparent diffusion coefficient (ADC) map and the mean ADC value for each tonsil was calculated. ADC values for normal and SCC tonsils were compared using the Mann- Whitney U-test. The median ADC and range (x10-3 mm² s-1) were found to be 0.814 and 0.548-1.312, respectively, for normal tonsils compared with 0.933 and 0.789-1.175, respectively, for SCC tonsils. ADC values were significantly higher for SCC tonsils than for normal tonsils (p50.009). No SCC tonsil had an ADC less than 0.82x10-3 mm² s-1 compared with 58% of normal tonsils. We conclude that there is a difference in the ADC between normal tonsils and SCC tonsils where the cancer is apparent on conventional MRI. These results are promising, although further studies are now required to determine whether DWI can be used to identify or exclude smaller foci of SCC within tonsils where the cancer is not evident on conventional MRI. [ABSTRACT FROM AUTHOR]

High-resolution ultrasound is now the imaging modality of choice for the assessment of the vast majority of palpable swellings in the head and neck. In experienced hands, it is frequently the only imaging technique required for diagnosis, as it can be performed rapidly, safely and permits accurate tissue sampling. A systematic approach to the sonographic assessment of neck lumps is provided, with practical advice including tips and pitfalls on scanning and fine-needle aspiration techniques. Reflecting the cumulative experience using sonography within a busy Quick Early Diagnosis clinic for patients with suspected head and neck cancer, emphasis is placed on the evaluation of the entire neck, including nodal drainage sites, the meticulous assessment of lymph nodes to identify often subtle features indicative of abnormality, the appreciation of typical features of common non-nodal pathologies, and the recognition of normal structures commonly mimicking neck lumps. In practice, additional imaging techniques, including CT and MRI, are not routinely required, and indications for these are outlined. [ABSTRACT FROM AUTHOR]

We review several new optical techniques which reveal the spatial distribution of excited atomic states. These techniques have been developed in different laboratories, largely as a result of exploiting laser excitation, which provides additional flexibility in the choice of excitation paths. Several methods are in use, which possess different advantages, but all share one common property. They sample the wavefunction of the excited state at different radii using different excitation paths, and are thereby sensitive to size. Amongst the radial phenomena which control the size of an atomic orbital, the most important are the centrifugal barrier effects which determine orbital collapse. [ABSTRACT FROM AUTHOR]

For over three decades, bone conduction hearing aids have been changing the lives of patients with impaired hearing. The size, appearance and fitting discomfort of early generations of bone conduction hearing aids made them unpopular. The advent of bone-anchored hearing aids in the 1970s offered patients improved sound quality and fitting comfort, due to the application of osseointegration. However, the issue of post-operative peri-abutment pin tract wound infection persisted. The Bonebridge system incorporates the first active bone conduction device, and aims to resolve peri-abutment issues. Implantation of this system in an Asian patient is presented. [ABSTRACT FROM PUBLISHER]

Measurements of electric field ionization of high Rydberg states populated by two-photon excitation are reported. We use a novel technique, in which the extraneous ionization background due to other causes is suppressed, resulting in higher accuracy and sensitivity than otherwise achievable. The method is applied to a series in the calcium spectrum which exhibits an interesting anomaly around n = 63 in previous experiments by laser spectroscopy using thermionic diode detection. In the present experiments, collisions are highly improbable, and it is demonstrated that electric field ionization then occurs without any detectable anomaly around n = 63. The implications of this for the interpretation of the effect are discussed. [ABSTRACT FROM AUTHOR]

Refractive indices of water and several organic liquids have been determined by an accurate method using a He-Ne laser. The method is in principle simpler than those used normally for such measurements. The experimental arrangement presented here is capable of yielding results with an accuracy of the order of 2 × 10[sup -5]. Comparison between the measured values and precise published results shows that they are nearly same within experimental parameters. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the influence of variations in resting pressure (precompression) on thyroid ultrasound supersonic shear wave elastography (SWE).Methods: Thirty-five normal thyroid glands (Norm), 55 benign hyperplastic nodules (BHN), and 17 papillary thyroid cancers (PTC) in 96 subjects underwent thyroid SWE. Four precompression levels were applied manually by the operator, ranging from A (baseline, 0 % strain) to D (high, 22-30 % strain). SWE results at each precompression level were compared using ANOVA tests with P < 0.05 indicating significance.Results: SWE indices were highest in PTC, followed by BHN and Norm at each precompression level (P < 0.05). All tissue types showed successive increases in SWE results as precompression increased, although the rate was higher for PTC than BHN and Norm (Ps < 0.05). SWE values (kPa) of Norm, BHN, and PTC at baseline precompression (A) were 10.3 ± 3.3, 17.7 ± 7.6, and 22.2 ± 11.9 compared with 21.1 ± 4.2, 42.3 ± 16.0, and 97.6 ± 46.8 at high precompression (D). SWE index differences between precompression levels A and D were 10.8 kPa for Norm, 24.6 kPa for BHN, and 75.4 kPa for PTC.Conclusion: PTCs show greater SWE stiffening than BHN as precompression rises. Precompression effects on thyroid nodules are not negligible and may account for wide discrepancies in published SWE discriminatory performance results for thyroid malignancy.Key Points: • Increases in resting pressure (precompression) applied by the operator increases thyroid stiffness. • Papillary cancers show greater increases in stiffness (strain hardening) than benign nodules. • Precompression may affect the diagnostic performance of shearwave elastography for thyroid malignancy. [ABSTRACT FROM AUTHOR]

A quiz concerning the diagnosis of several medical cases with imaging is presented.