Endometrial reflectivity (ultrasound grading)
Endometrial reflectivity grading on ultrasound is a system initially proposed by Smith et al. in 1984 which classifies the endometrium into four types according to the echotexture pattern. They are considered to be useful in deciding on receptivity in in-vitro fertilisation (IVF).
The Smith system is as follows:
- grade A: hyperechoic
- grade B: isoechoic
- grade C: triple line / trilaminar
- grade D: echogenic black region surrounding the midline echo
Further versions have been proposed subsequently which include a 3-grade system by Gonen and Casper in 1990.
- type a: entirely homogeneous, hyperechogenic pattern, without a central echogenic line
- type b: intermediate iso-echogenic pattern, with the same reflectivity as the surrounding myometrium and a non-prominent or absent central echogenic line
- type c: multilayered ‘triple-line’ endometrium consisting of a prominent outer and central hyperechogenic line and inner hypo-echogenic or black region
Or a two grade system by Sher et al. in 1991:
- non-multilayered homogeneous hyperechogenic or iso-echogenic endometrium compared with the myometrium
- multilayered triple-line multilayered pattern, ‘halo pattern’ = outer peripheral layer of denser echogenicity and a central sonolucent area.
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