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  • Publication
    Poor agreement between operators on grading of the placenta
    Abnormal placental grading is associated with poor pregnancy outcome. The aim of this study was to measure intra- and interobserver variability in placental grading. Five expert sonographers independently graded 90 images on two occasions, each viewing separated by 1 week. A number of measures were employed to standardise assessment and minimise potential for variation: prior agreement was established between observers on the classifications for placental grading; a controlled viewing laboratory was used for all viewings; ambient lighting was optimal and monitors were calibrated to the GSDF standard. Kappa (κ) analysis was used to measure observer agreement. Substantial variations between individuals' scores were observed. A mean κ-value of 0.34 (range from 0.19 to 0.50) indicated fair interobserver agreement over the two occasions and only nine of the 90 images were graded the same by all five observers. Intraobserver agreement had a moderate mean κ-value of 0.52, with individual comparisons ranging from 0.45 to 0.66. This study demonstrates that, despite standardised viewing conditions, Grannum grading of the placenta is not a reliable technique even among expert observers. The need for new methods to assess placental health is required and work is ongoing to develop 2D and 3D software-based methods.
    Scopus© Citations 18  665
  • Publication
    Is Grannum Grading of the Placenta Reproducible?
    Current ultrasound assessment of placental calcification relies on Grannum grading. The aim of this study was to assess if this method is reproducible by measuring inter- and intra-observer variation in grading placental images, under strictly controlled viewing conditions. Thirty placental images were acquired and digitally saved. Five experienced sonographers independently graded the images on two separate occasions. In order to eliminate any technological factors which could affect data reliability and consistency all observers reviewed images at the same time. To optimise viewing conditions ambient lighting was maintained between 25-40 lux, with monitors calibrated to the GSDF standard to ensure consistent brightness and contrast. Kappa (κ) analysis of the grades assigned was used to measure inter- and intra-observer reliability. Intra-observer agreement had a moderate mean κ-value of 0.55, with individual comparisons ranging from 0.30 to 0.86. Two images saved from the same patient, during the same scan, were each graded as I, II and III by the same observer. A mean κ-value of 0.30 (range from 0.13 to 0.55) indicated fair inter-observer agreement over the two occasions and only one image was graded consistently the same by all five observers. The study findings confirmed the lack of reproducibility associated with Grannum grading of the placenta despite optimal viewing conditions and highlight the need for new methods of assessing placental health in order to improve neonatal outcomes. Alternative methods for quantifying placental calcification such as a software based technique and 3D ultrasound assessment need to be explored.
    Scopus© Citations 2  411