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Comparison between automatic and manual methods to the measurement of fraction limb volume by three-dimensional ultrasonography: validation of a new software in a Brazilian population

Grant number: 13/01464-0
Support type:Regular Research Grants
Duration: June 01, 2013 - May 31, 2015
Field of knowledge:Health Sciences - Medicine
Principal Investigator:Edward Araujo Júnior
Grantee:Edward Araujo Júnior
Home Institution: Escola Paulista de Medicina (EPM). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil
Assoc. researchers:Luciano Marcondes Machado Nardozza

Abstract

Background: The two-dimensional ultrasonography (2DUS) is traditionally used worldwide for the prediction of fetal birth weight, however, in advanced gestational ages, there is shown a method imprecise due to the larger relative decrease in the fetal and amniotic fluid volume. The ultrasound three-dimensional (3DUS) due to capacity division of the outer surface of the structures, enables to effectively measure the soft tissue of fetal limb, assessing the status nutritional and prediction of fetal birth weight. The fraction limb volume (FLV), described by Lee et al. in 1998, corresponding to 50% of the volume of the central portion of the limb, which contains the highest amount of soft tissue. The manual FLV is a validated method for assessing status nutritional and prediction of fetal weight, and commercially available software in the Voluson E8 machine (General Electric Medical System, Healthcare, Zipf, Austria). However, the calculation of FLV by the manual method spends much time, and it is operator dependent. Recently, Siemens AG (Siemens Corp., Erlangen, Germany) designed a software called Auto OB for automatic calculation of fetal two-dimensional structures. Prof. Wesley Lee, now at Baylor College of Medicine, developed together with the company Tomtec Imaging System (Munich,Germany) an Auto OB software for automatic calculation of the FLV, which at present is being validated only in the US population. Purpose: The automatic method, if proven its validation is faster and less operator dependent, allowing its commercial sale to clinicians and researchers in the world, so the most practical way of assessing the nutritional status and prediction of fetal birth weight. Objective: 1. To obtain an ACUSON S-2000 machine (Siemens, Erlangen, Germany) for validation of an automatic calculation software of FLV in a Brazilian population; 2. To compare the manual and automatic methods for calculating of FLV in a sample of Brazilian pregnant women, so if you try to validate new software. Methods: It will be a prospective cross-sectional study with 120 pregnant women who are predicting to have their births within of four days at Department of Obstetrics, Paulista School of Medicine, Federal University of São Paulo (EPM-UNIFESP). We will use an ACUSON S-2000 machine (Siemens, Erlangen, Germany) with a convex volumetric transductor. We will calculate of fraction fetal arm and thigh volumes using manual methods, which consist of five delimitation plans equidistant from each other, and the automatic method. To evaluate the agreement between the techniques it will be used the Bland-Altman plots. To verify differences in calculation time of each technique, we will use the paired Student t test. To verify differences between estimated fetal weight by both techniques in relation to actual weight at birth, it will be used the McNemar test. Expected results: The proof of validation of new software will permit the patenting of the same, including the names of researchers from the São Paulo state. This will allow that the company Siemens AG can sell commercially the software, enabling researchers around the world a new tool to study of fetal status nutrition. For the Brazilian group, this validation will open new opportunities of multicenter studies, and the possibility of new software validations, contributing to the development of science and technology in our country. For physicians, enable a new tool for monitoring of high-risk fetuses with intrauterine growth disorders, contributing to reduction of perinatal morbidity and mortality. (AU)