Real-time algorithm for Poissonian noise reduction in low-dose fluoroscopy: performance evaluation.

BACKGROUND: Quantum noise intrinsically limits the quality of fluoroscopic images. The lower is the X-ray dose the higher is the noise. Fluoroscopy video processing can enhance image quality and allows further patient's dose lowering. This study aims to assess the performances achieved by a Noise Variance Conditioned Average (NVCA) spatio-temporal filter for real-time denoising of fluoroscopic sequences. The filter is specifically designed for quantum noise suppression and edge preservation. It is an average filter that excludes neighborhood pixel values exceeding noise statistic limits, by means of a threshold which depends on the local noise standard deviation, to preserve the image spatial resolution. The performances were evaluated in terms of contrast-to-noise-ratio (CNR) increment, image blurring (full width of the half maximum of the line spread function) and computational time. The NVCA filter performances were compared to those achieved by simple moving average filters and the state-of-the-art video denoising block matching-4D (VBM4D) algorithm. The influence of the NVCA filter size and threshold on the final image quality was evaluated too. RESULTS: For NVCA filter mask size of 5 × 5 × 5 pixels (the third dimension represents the temporal extent of the filter) and a threshold level equal to 2 times the local noise standard deviation, the NVCA filter achieved a 10% increase of the CNR with respect to the unfiltered sequence, while the VBM4D achieved a 14% increase. In the case of NVCA, the edge blurring did not depend on the speed of the moving objects; on the other hand, the spatial resolution worsened of about 2.2 times by doubling the objects speed with VBM4D. The NVCA mask size and the local noise-threshold level are critical for final image quality. The computational time of the NVCA filter was found to be just few percentages of that required for the VBM4D filter. CONCLUSIONS: The NVCA filter obtained a better image quality compared to simple moving average filters, and a lower but comparable quality when compared with the VBM4D filter. The NVCA filter showed to preserve edge sharpness, in particular in the case of moving objects (performing even better than VBM4D). The simplicity of the NVCA filter and its low computational burden make this filter suitable for real-time video processing and its hardware implementation is ready to be included in future fluoroscopy devices, offering further lowering of patient's X-ray dose.

Development of a Prototype E-Textile Sock.

The aim of this work is to design and develop a sensorized sock in Electronic Textile (ET), SWEET-Sock. The device has been realized by three textile sensor placed in a specific points of plantar arch and an accelerometer unit, both embedded and connected by conductive thread. The sensors allows the acquisition of plantar pressure and acceleration signals deriving from the motion of the lower limbs. The detected biosignals have been condictionated by a voltage divider and then were acquired through a LilyPad Arduino microcontroller and transmitted using the Simblee BLE technology to a custom made mobile app. Data were afterwards uploaded through a smartphone on a dropbox cloud where a custom made MATLAB GUI platform has been developed for further digital signal processing of main biomechanical parameters of clinical interest in postural and gait analysis.

Tolerance to silver of an Aspergillus fumigatus strain able to grow on cyanide containing wastes.

We studied the strategy of an Aspergillus fumigatus strain able to grow on metal cyanide wastes to cope with silver. The tolerance test revealed that the Minimum Inhibitory Concentration of Ag(I) was 6mM. In 1mM AgNO3 aqueous solution the fungus was able to reduce and sequestrate silver into the cell in the form of nanoparticles as evidenced by the change in color of the biomass and Electron Microscopy observations. Extracellular silver nanoparticle production also occurred in the filtrate solution after previous incubation of the fungus in sterile, double-distilled water for 72h, therefore evidencing that culture conditions may influence nanoparticle formation. The nanoparticles were characterized by UV-vis spectrometry, X-ray diffraction and Energy Dispersion X-ray analysis. Atomic absorption spectrometry revealed that the optimum culture conditions for silver absorption were at pH 8.5.The research is part of a polyphasic study concerning the behavior of the fungal strain in presence of metal cyanides; the results provide better understanding for further research targeted at a rationale use of the microorganism in bioremediation plans, also in view of possible metal recovery. Studies will be performed to verify if the fungus maintains its ability to produce nanoparticles using KAg(CN)2.

[Fiberendoscopic sclerotherapy of esophageal varices: relationship of varices size, quantity of sclerosing agent used and number of sessions]. / Escleroterapia fibroendoscópica de várices esofágicas: relación entre el tamaño de las várices, cantidad de esclerosante empleado y número de sesiones.

By means of fiberendoscopic injection sclerotherapy, it was possible to achieve eradication of esophageal varices in 18 patients. At the onset of treatment 9 patients had small varices (grade II) and other 9 had big varices (grade III). It was found in the big varices group there was needed more courses (p less than 0.01) and a greater amount of sclerosing agent (p less than 0.001) than in the group with small varices. Since those patients with big varices required more courses and more volume of sclerosing agent, and in fact they have more risk to rebleed during the pre-eradication period. It is proposed as a solution during this period, the use of a B receptor blocking agent (Propranolol) simultaneously with sclerotherapy.

Escleroterapia fibroendoscópica de várices esofágicas: relación entre el tamaño de las várices, cantidad de esclerosante empleado y número de sesiones. / [Fiberendoscopic sclerotherapy of esophageal varices: relationship of varices size, quantity of sclerosing agent used and number of sessions]

By means of fiberendoscopic injection sclerotherapy, it was possible to achieve eradication of esophageal varices in 18 patients. At the onset of treatment 9 patients had small varices (grade II) and other 9 had big varices (grade III). It was found in the big varices group there was needed more courses (p less than 0.01) and a greater amount of sclerosing agent (p less than 0.001) than in the group with small varices. Since those patients with big varices required more courses and more volume of sclerosing agent, and in fact they have more risk to rebleed during the pre-eradication period. It is proposed as a solution during this period, the use of a B receptor blocking agent (Propranolol) simultaneously with sclerotherapy.

Escleroterapia fobroendoscopica de varices esofagicas: relacion entre el tamano de las varices, cantidad de esclerosante empleado u numero de sesiones. / Fiberendoscopic sclerotherapy of esophageal varices: relationship of varices size, quantity of sclerosing agent used and number of sessions

Mediante tratamiento esclerosante fibroendoscopico, se logro en 18 pacientes la erradicacion de sus varices esofagicas.Nueve pacientes presentaban al inicio de la terapeutica varices pequenas (grado III) y otros nueve varices grandes (grado III). Se comprueba que el grupo con varices grandes, requieren en forma estadisticamente significativa (p <0,01) mayor cantidad de sesiones y (p < 0.001) mayor volumen de esclerosante que el grupo con varices pequenas. Al requerir estos pacientes con varios esofagicas grandes mas sesiones y volumen de agente esclerosante, y ser al mismo tiempo los que tienen mayor riesgo de presentar recidivas hemorragicas durante el periodo preerradicatorio, se propone como solucion durante este lapso el empleo de los bloqueantes de los receptores B adrenergicos (propanolol) en forma simultanea a la escleroterapia

Escleroterapia fobroendoscopica de varices esofagicas: relacion entre el tamano de las varices, cantidad de esclerosante empleado u numero de sesiones. / Fiberendoscopic sclerotherapy of esophageal varices: relationship of varices size, quantity of sclerosing agent used and number of sessions

Mediante tratamiento esclerosante fibroendoscopico, se logro en 18 pacientes la erradicacion de sus varices esofagicas.Nueve pacientes presentaban al inicio de la terapeutica varices pequenas (grado III) y otros nueve varices grandes (grado III). Se comprueba que el grupo con varices grandes, requieren en forma estadisticamente significativa (p <0,01) mayor cantidad de sesiones y (p < 0.001) mayor volumen de esclerosante que el grupo con varices pequenas. Al requerir estos pacientes con varios esofagicas grandes mas sesiones y volumen de agente esclerosante, y ser al mismo tiempo los que tienen mayor riesgo de presentar recidivas hemorragicas durante el periodo preerradicatorio, se propone como solucion durante este lapso el empleo de los bloqueantes de los receptores B adrenergicos (propanolol) en forma simultanea a la escleroterapia