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OBJECTIVES Prader-Willi syndrome (PWS) is a neurogenetic disorder characterized by mental retardation, morbid obesity, and endocrine and behavior disorders. We previously showed in a small group of patients that PWS may have a unique prenatal phenotype. We aimed to characterize clinical and ultrasonic features in a larger series of pregnancies with a PWS fetus. METHODS We retrospectively interviewed all mothers of children with PWS followed in the Israel national multidisciplinary PWS clinic. We compared details of the PWS pregnancy with the pregnancies of healthy siblings and with data from the general population. Medical records including ultrasound reports, obstetric records, and genetic results were analyzed. RESULTS Distinct prenatal features of PWS pregnancies included abnormal fetal growth [fetal growth restriction (FGR) (37.3%), increased head to abdominal circumference ratio (44.8%), decreased abdominal circumference (49.2%)], markedly decreased fetal movements (DFM) (80.4%), and polyhydramnios (42.0%) (P

A novel prototype electrical impedance tomography (EIT) system, which uses single-ended signalling, is presented. The single-ended electrical impedance tomography system consists of a host computer, data acquisition system, switching box, MATLAB, and LabVIEW program. Ability of the system to detect and track hidden conductive and non-conductive objects was examined using a beaker (cylindrical shape) of 180 mm diameter and 280 mm height, filled with 3000 mL tap water, and with 16 electrodes attached. Stainless steel and Teflon rods with different sizes were placed in different locations inside the beaker, and images were obtained. All the objects were tested under multiple signal injection frequencies in the range of 12–1000 kHz. The results showed that the system could detect and track conductive and non-conductive objects during certain injection frequencies. The single-ended EIT system requires one wire connection to make one signal injection or measurement, and this is controlled using a multiplexer or switching box. Alternatively, an ordinary EIT system requires additional wire connections for single data measurement or injection, and a more complex circuit to control the I/O signals. This greater number of wires and increased circuit complexity will increase the data error rate and the cost significantly.

This paper presents a multitasking electrical impedance tomography (EIT) system designed to improve the flexibility and durability of an existing EIT system. The ability of the present EIT system to detect, locate, and reshape objects was evaluated by four different experiments. The results of the study show that the system can detect and locate an object with a diameter as small as 1.5 mm in a testing tank with a diameter of 134 mm. Moreover, the results demonstrate the ability of the current system to reconstruct an image of several dielectric object shapes. Based on the results of the experiments, the programmable EIT system can adapt the EIT system for different applications without the need to implement a new EIT system, which may help to save time and cost. The setup for all the experiments consisted of a testing tank with an attached 16-electrode array made of titanium alloy grade 2. The titanium alloy electrode was used to enhance EIT system’s durability and lifespan.