A Novel Semiautomated Fractional Limb Volume Tool for Rapid and Reproducible Fetal Soft Tissue Assessment

J Ultrasound Med. 2016 Jul;35(7):1573-8. doi: 10.7863/ultra.15.09086. Epub 2016 Jun 7.


The purpose of this study was to document the reproducibility and efficiency of a semiautomated image analysis tool that rapidly provides fetal fractional limb volume measurements. Fifty pregnant women underwent 3-dimensional sonographic examinations for fractional arm and thigh volumes at a mean menstrual age of 31.3 weeks. Manual and semiautomated fractional limb volume measurements were calculated, with the semiautomated measurements calculated by novel software (5D Limb Vol; Samsung Medison, Seoul, Korea). The software applies an image transformation method based on the major axis length, minor axis length, and limb center coordinates. A transformed image is used to perform a global optimization technique for determination of an optimal limb soft tissue boundary. Bland-Altman analysis defined bias with 95% limits of agreement (LOA) between methods, and timing differences between manual versus automated methods were compared by a paired t test. Bland-Altman analysis indicated an acceptable bias with 95% LOA between the manual and semiautomated methods: mean arm volume ± SD, 1.7% ± 4.6% (95% LOA, -7.3% to 10.7%); and mean thigh volume, 0.0% ± 3.8% (95% LOA, -7.5% to 7.5%). The computer-assisted software completed measurements about 5 times faster compared to manual tracings. In conclusion, semiautomated fractional limb volume measurements are significantly faster to calculate when compared to a manual procedure. These results are reproducible and are likely to reduce operator dependency. The addition of computer-assisted fractional limb volume to standard biometry may improve the precision of estimated fetal weight by adding a soft tissue component to the weight estimation process.

Keywords: 3-dimensional sonography; estimated fetal weight; fractional arm volume; fractional thigh volume; obstetric ultrasound.

MeSH terms

  • Arm / diagnostic imaging*
  • Arm / embryology
  • Cohort Studies
  • Female
  • Humans
  • Image Processing, Computer-Assisted / methods*
  • Imaging, Three-Dimensional / methods*
  • Pregnancy
  • Prospective Studies
  • Reproducibility of Results
  • Thigh / diagnostic imaging*
  • Thigh / embryology
  • Ultrasonography, Prenatal / methods*