Ultraschall in der Medizin : Organ der Deutschen Gesellschaft für Ultraschall in der Medizin, [der] Österreichischen Gesellschaft für Ultraschall in der Medizin, [der] Schweizerischen Gesellschaft für Ultraschall in Medizin und Biologie
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Conventional sonography at 2 - 10 MHz cannot permeate the chest because ultrasound at this frequency is strongly scattered and reflected by air inclusions in the lungs. Therefore, sonography is considered impracticable for thoracic imaging. However, human thoraxes and lungs in situ were never rigorously probed with ultrasound at frequencies below 1 MHz. In addition, ultrasound is commonly applied as echo imaging rather than sound transmission. ⋯ Sound transmission in the lungs is characterized by three distinct frequency bands. Low frequency ultrasound is transmitted through the lungs and may offer a novel non-invasive approach to real time diagnostics.
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To evaluate and compare the accuracy of different formulas to estimate fetal weight using 2D and 3D ultrasound. ⋯ The best option with the highest accuracy for sonographic fetal weight estimation was the 3D Schild equation followed by the 2D Hansmann and Merz formulas. Published data of the accuracy could be reproduced with the exception of the "Asian" 3D equations in our European population. The limited improvement in weight agreement using the 3D technique compared to the 2D technique may be outweighed by the time consumption.