Enhanced Vascular Features in Porcine Gastrointestinal Endoscopy Using Multispectral Imaging.

Endoscopic investigation is a predominant stan-dard while assessing the gastrointestinal tract. Even though it has been rigorously used in diagnostics for many decades, a high miss rate has been recorded. Advanced endoscopic imaging still has not found solutions to problems like early cancer detection, polyp generality, disease classification, etc. One of the less explored techniques to study early cancer detection is spectral imaging which deals with the absorption and reflection spectra of various wavelengths of light by different layers of tissue. To study tissues under various illumination, a multi-spectral light source unit that can be used along with an endoscopy system was developed with 10 different LEDs of very narrow bandwidths. Using this light source, a feasibility study was per-formed on an animal in which the upper GI tract of a porcine model was imaged and sample images were taken for processing from five different sections. Some wavelengths showed better contrast enhancements for visualization of vascular structures. Wavelength 420 nm (violet light) showed better contrast and the gradient of the line profile histogram showed the highest intensity change between the blood vessels and the surrounding mucosa. These enhancements showed that spectral imaging can potentially help in studying tissues for early cancer detection and improved visualization of the G I tract using endoscopy.

A strategy to determine off-axis dosimetric leaf gap using OSLD and EPID.

BACKGROUND: The aim of the study was to investigate the dosimetric feasibility of using optically stimulated luminescence dosimeters (OSLD) and an electronic portal imaging device (EPID) for central axis (CA X) and off-axis (OAX) dosimetric leaf gap (DLG) measurement. MATERIALS AND METHODS: The Clinac 2100C/D linear accelerator equipped with Millennium-120 multileaf collimator (MLC) and EPID was utilized for this study. The DLG values at CA X and ± 1 cm OAX (1 cm superior and inferior to the CA X position, respectively along the plane perpendicular to MLC motion) were measured using OSLD (DLGOSLD) and validated using ionization chamber dosimetry (DLGICD). The two-dimensional DLG map (2D DLGEPID) was derived from the portal images of the DLG plan using a custom-developed software application that incorporated sliding aperture-specific correction factors. RESULTS: DLGOSLD and DLGICD, though measured with diverse setup in different media, showed similar variation both at CA X and ± 1 cm OAX positions. The corresponding DLGEPID values derived using aperture specific corrections were found to be in agreement with DLGOSLD and DLGICD. The 2D DLGEPID map provides insight into the varying patterns of the DLG with respect to each leaf pair at any position across the exposed field. CONCLUSIONS: Commensurate results of DLGOSLD with DLGICD values have proven the efficacy of OSLD as an appropriate dosimeter for DLG measurement. The 2D DLGEP ID map opens a potential pathway to accurately model the rounded-leaf end transmission with discrete leaf-specific DLG values for commissioning of a modern treatment planning system.

The Spectrum of Autonomic Dysfunction in Myasthenic Crisis.

BACKGROUND: Autoimmune autonomic dysfunction is described in Myasthenia Gravis. In myasthenic crisis, the spectrum of autonomic dysfunction is hitherto uncharacterized. OBJECTIVE: The objective of this study is to describe the spectrum of autonomic dysfunction in myasthenic crises using the composite autonomic symptom scale 31 (COMPASS 31) autonomic symptom questionnaire and power spectral analysis of heart rate variability (HRV), which is a simple way of estimating general autonomic dysfunction. METHODS: Adult patients with myasthenic crisis from January 1, 2014 to March 15, 2015, were prospectively included in this study. The COMPASS 31 questionnaire for symptoms of autonomic dysfunction and power spectral analysis of HRV were assessed. These were compared with the patient's demographic and clinical parameters and with previous literature. IRB approval was obtained. RESULTS: Sixteen patients were included (M:F 3:1). 15/16 patents (93%) had autonomic dysfunction on COMPASS 31 questionnaire. The domains of involvement were gastrointestinal (80%), orthostatic (67.7%), pupillomotor (67.7%); sudomotor (33.3%), and vasomotor (13.3%). Parasympathetic dysfunction predominance was suggested by the symptom profile. HRV analysis showed a low frequency (LF) spectral shift suggesting slowed parasympathetic responsiveness (LF normalized unit (nu): high frequency [HF] nu mean 8.35, standard deviation ± 5.4, 95% confidence interval 2.2-12.5), which significantly exceeded the mean LF nu: HF nu ratios of the majority of previously reported noncrises myasthenic populations. CONCLUSIONS: Myasthenic crisis has autonomic dysfunction involving multiple organ systems. Increased latency of parasympathetic reflexes is suggested. A comprehensive management protocol addressing different autonomic domains is required for holistic patient care.