Nuchal translucency thickness measurement: repeatability using a virtual ultrasound scanner

Area of Science:

• Medical Imaging
• Fetal Ultrasound Technology

Background:

• Nuchal translucency (NT) measurement is crucial for fetal aneuploidy screening.
• Operator variability can impact the accuracy of NT measurements.
• A consistent and reliable method for assessing measurement repeatability is needed.

Purpose of the Study:

• To evaluate the inter- and intraoperator repeatability of nuchal translucency (NT) thickness measurements using a PC-based virtual ultrasound scanner (VirUS).
• To assess the performance of experienced ultrasound operators in a simulated NT measurement environment.

Main Methods:

• Simulated fetal ultrasound images with defined NT thickness were generated using VirUS.
• Thirteen experienced operators performed NT thickness measurements on a set of 50 simulated images across three separate occasions.
• A total of 1950 measurements were collected to assess repeatability.

Main Results:

• Interoperator repeatability was +/- 0.41 mm and intraoperator repeatability was +/- 0.22 mm (95% confidence level).
• Significant correlations were found between repeatability and mean measured NT thickness, as well as between scanner gain settings and measured thickness.
• Operator performance varied, with some showing significant correlations between gain and measurement outcomes.

Conclusions:

• The virtual ultrasound scanner (VirUS) provides a consistent environment for auditing NT measurements.
• Optimizing repeatability in relation to mean measured thickness and ensuring consistent gain settings are critical for accurate NT assessment.
• VirUS demonstrates potential as a tool for operator training and quality assurance in NT measurement.