Endometrial thickness
Updates to Article Attributes
Endometrial thickness is a commonly measured parameter on routine gynaecological ultrasound and MR imaging. The appearance as well as the thickness of the endometrium will depend on whether the patient is of reproductive age or post-menopausal and, if of reproductive age, at what point in the menstrual cycle they are examined. This article provides normal ranges for endometrial thickness.
Radiographic features
Ultrasound (endovaginal)
The endometrium should be measured in the long axis or sagittal plane. The measurement is of the thickest echogenic area from one basal endometrial interface across the endometrial canal to the other basal surface. Care should be taken not to include the hypoechoic myometrium in this measurement.
The normal endometrium changes in appearance as well as in thickness throughout the menstrual cycle.
- in the menstrual and early proliferative phase it is a thin, brightly echogenic stripe comprising of the basal layer (Figure 1)
- in the late proliferative phase it develops a trilaminar appearance: outer echogenic basal layer, middle hypoechoic functional layer, and an inner echogenic stripe at the central interface (Figure 2)
- in the secretory phase it is at its thickest and becomes uniformly echogenic, as the functional layer becomes oedematous and isoechoic to the basal layer (Figure 3).
The postmenopausal endometrium should be smooth and homogeneous.
Normal range of endometrial thickness
The designation of normal limits of endometrial thickness rests on determining at which thickness the risk of endometrial carcinoma is significantly increased.
Whilst qualitative assessment is important, endometrial morphology and the presence of risk factors for endometrial malignancy should be taken into account when deciding whether or not endometrial sampling is indicated.
Commonly accepted endovaginal ultrasound values are as follows:.
Premenopausal
In premenopausal patients there is significant variation by stage of the menstrual cycle.
- during menstruation 1,4: 2-4 mm
- early proliferative phase (day 6-14): 5-7 mm
- late proliferative-pre ovulatory phase: up to 11 mm
- secretory phase: 7-16 mm
- following dilatation and curettage or spontaneous abortion: <5 mm, if it is thicker consider retained products of conception.
Postmenopausal
Will depend on the usewhether or not there is a history of use ofvaginal bleeding, and on use of hormonal therapy / tamoxifen.
-
if on no medication5: <5 mm-
if there ishistory of vaginal bleeding, the(and not on HRT/tamoxifen):- suggested upper limit of normal is < 5 mm5
- risk of carcinoma is ~7% if endometrium is >5 mm and 0.07% if endometrium is <5mm8
-
if thereno history of vaginal bleeding (and not on HRT/tamoxigen):-
acceptable range of endometrial thickness is
no bleedingless well established in this group,thecut-off values of 8 or 11 mm have been suggested. - risk of carcinoma is ~7% if the endometrium is
>11 mm>11mm, and 0.002% if endometrium is <11mm8
-
acceptable range of endometrial thickness is
- if on hormonal therapy 6: upper limit is 8-15 mm
- if on tamoxifen 3: <
;6; 6 mm (although ~50% of those receiving tamoxifen have been reported to have thickness of >8 mm 7)
MRI
Endometrial thickness is well assessed on MRI. Measurement should be taken at a mid saggital slice, similar to the US assessment plane.
The normal endometrium is homogeneously hyperintense on T2WI, regardless of the phase of menstrual cycle or menopausal status and well outlined by the low signal myometrial junctional zone.
See also
-
-<p><strong>Endometrial thickness</strong> is a commonly measured parameter on routine <a href="/articles/gynaecological-ultrasound-set-pieces">gynaecological ultrasound</a> and MR imaging. The appearance as well as the thickness of the endometrium will depend on whether the patient is of reproductive age or post-menopausal and, if of reproductive age, at what point in the menstrual cycle they are examined. This article provides normal ranges for endometrial thickness.</p><h4>Radiographic features</h4><h5>Ultrasound (endovaginal)</h5><p>The endometrium should be measured in the long axis or sagittal plane. The measurement is of the thickest echogenic area from one basal endometrial interface across the endometrial canal to the other basal surface. Care should be taken not to include the hypoechoic myometrium in this measurement.</p><h6>Normal range</h6><p>Commonly accepted endovaginal ultrasound values are as follows:</p><p><strong>Premenopausal</strong></p><p>In premenopausal patients there is significant variation by stage of the menstrual cycle.</p><ul>- +<p><strong>Endometrial thickness</strong> is a commonly measured parameter on routine <a href="/articles/gynaecological-ultrasound-set-pieces">gynaecological ultrasound</a> and MR imaging. The appearance as well as the thickness of the endometrium will depend on whether the patient is of reproductive age or post-menopausal and, if of reproductive age, at what point in the menstrual cycle they are examined. </p><h4>Radiographic features</h4><h5>Ultrasound (endovaginal)</h5><p>The endometrium should be measured in the long axis or sagittal plane. The measurement is of the thickest echogenic area from one basal endometrial interface across the endometrial canal to the other basal surface. Care should be taken not to include the hypoechoic myometrium in this measurement.</p><p>The normal endometrium changes in appearance as well as in thickness throughout the menstrual cycle. </p><ul>
- +<li>in the menstrual and early proliferative phase it is a thin, brightly echogenic stripe comprising of the basal layer (Figure 1)</li>
- +<li>in the late proliferative phase it develops a trilaminar appearance: outer echogenic basal layer, middle hypoechoic functional layer, and an inner echogenic stripe at the central interface (Figure 2)</li>
- +<li>in the secretory phase it is at its thickest and becomes uniformly echogenic, as the functional layer becomes oedematous and isoechoic to the basal layer (Figure 3).</li>
- +</ul><p>The postmenopausal endometrium should be smooth and homogeneous.</p><h6>Normal range of endometrial thickness</h6><p>The designation of normal limits of endometrial thickness rests on determining at which thickness the risk of endometrial carcinoma is significantly increased. </p><p>Whilst qualitative assessment is important, endometrial morphology and the presence of risk factors for endometrial malignancy should be taken into account when deciding whether or not endometrial sampling is indicated.</p><p>Commonly accepted endovaginal ultrasound values are as follows.</p><p><strong>Premenopausal</strong></p><p>In premenopausal patients there is significant variation by stage of the menstrual cycle.</p><ul>
-</ul><p><strong>Postmenopausal</strong></p><p>Will depend on the use of use of hormonal therapy / tamoxifen</p><ul>-<li>if on no medication <sup>5</sup>: <5 mm<ul>-<li>if there is vaginal bleeding, the risk of carcinoma is ~7% if endometrium is >5 mm <sup>8 </sup>- +</ul><p><strong>Postmenopausal</strong></p><p>Will depend on the whether or not there is a history of vaginal bleeding, and on use of hormonal therapy / tamoxifen.</p><ul>
- +<li>history of vaginal bleeding (and not on HRT/tamoxifen):<ul>
- +<li>suggested upper limit of normal is < 5 mm<sup>5</sup>
-<li>if there is no bleeding, the risk of carcinoma is ~7% if the endometrium is >11 mm <sup>8 </sup>- +<li>risk of carcinoma is ~7% if endometrium is >5 mm and 0.07% if endometrium is <5mm<sup>8 </sup>
- +</li>
- +</ul>
- +</li>
- +<li>no history of vaginal bleeding (and not on HRT/tamoxigen):<ul>
- +<li>acceptable range of endometrial thickness is less well established in this group, cut-off values of 8 or 11 mm have been suggested. </li>
- +<li>risk of carcinoma is ~7% if the endometrium is >11mm, and 0.002% if endometrium is <11mm<sup>8</sup>
-<li>if on tamoxifen <sup>3</sup>: <6 mm (although ~50% of those receiving tamoxifen have been reported to have thickness of >8 mm <sup>7</sup>)</li>-</ul><h4>See also</h4><ul>- +<li>if on tamoxifen <sup>3</sup>: < 6 mm (although ~50% of those receiving tamoxifen have been reported to have thickness of >8 mm <sup>7</sup>)</li>
- +</ul><h5>MRI</h5><p>Endometrial thickness is well assessed on MRI. Measurement should be taken at a mid saggital slice, similar to the US assessment plane.</p><p>The normal endometrium is homogeneously hyperintense on T2WI, regardless of the phase of menstrual cycle or menopausal status and well outlined by the low signal myometrial junctional zone.</p><h4>See also</h4><ul>
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