A New Method to Measure the Subpubic Arch Angle Using 3-D Ultrasound

Area of Science:

• Obstetrics and Gynecology
• Medical Imaging
• Fetal Biometry

Background:

• Accurate measurement of the subpubic angle (SPA) is crucial for assessing pelvic dimensions in pregnant women.
• Evaluating new imaging techniques for SPA measurement is essential for improving obstetric assessments.

Purpose of the Study:

• To assess the reproducibility of the Oblique View eXtended Imaging (OVIX) and 3-D multiplanar technique (MPT) for subpubic angle measurement.
• To evaluate the intermethod agreement between OVIX and MPT in term gestation women.

Main Methods:

• Transperineal 3-D ultrasound volumes were acquired from 155 women at term gestation.
• Subpubic angles were measured twice by one operator and once by another using both OVIX and MPT.
• Reproducibility and intermethod agreement were analyzed using intraclass correlation coefficients (ICC) and Bland-Altman methods.

Main Results:

• OVIX demonstrated high intraobserver (ICC 0.912) and good interobserver (ICC 0.791) agreement for SPA measurement.
• MPT showed moderate intraobserver (ICC 0.573) and good interobserver (ICC 0.640) agreement.
• Good intermethod agreement was found between OVIX and MPT (ICC 0.614), though MPT measurements were significantly wider.

Conclusions:

• The Oblique View eXtended Imaging (OVIX) technique is a reliable method for subpubic angle measurement.
• The 3-D multiplanar technique (MPT) tends to overestimate subpubic angle measurements compared to OVIX.
• Further research is warranted to determine the clinical utility of these techniques.