From the Guidelines
The endometrial stripe is a critical layer of tissue that lines the inside of the uterus, visible as a bright line on ultrasound imaging, with a thickness that varies throughout the menstrual cycle and is a key indicator for evaluating gynecological conditions, including abnormal uterine bleeding and endometrial cancer. The endometrial stripe consists of the endometrium, which thickens and sheds during a woman's menstrual cycle, and its measurement is important for assessing various gynecological conditions. According to the American College of Radiology 1, during a transvaginal or abdominal ultrasound, the endometrial stripe appears as a white line in the center of the uterus.
The thickness of the endometrial stripe is a significant factor in evaluating gynecological conditions, with a normal thickness typically ranging from 4-8mm in premenopausal women and less than 5mm in postmenopausal women 1. Measuring the endometrial stripe is crucial for identifying potential issues, such as abnormal uterine bleeding, infertility, and screening for endometrial cancer. A thickened endometrial stripe in postmenopausal women may indicate hyperplasia or cancer and typically requires further evaluation with endometrial biopsy 1.
Key points to consider when evaluating the endometrial stripe include:
- The appearance and thickness of the endometrial stripe change predictably throughout the menstrual cycle due to hormonal influences 1
- The thinnest measurement of the endometrial stripe occurs just after menstruation, and the thickest measurement occurs before menstruation as the body prepares for possible pregnancy 1
- An endometrial thickness of 4 mm in a postmenopausal woman conveys a negative predictive value for cancer of nearly 100% 1
- In premenopausal women, normal endometrial thickness varies with the phase of the menstrual cycle, and there is no validated absolute upper limit cutoff for endometrial thickness 1
From the Research
Definition of Endometrial Stripe
- The endometrial stripe refers to the thickness of the endometrium, which is the lining of the uterus, as measured by transvaginal sonography 2.
- The endometrial stripe thickness is an important parameter in the evaluation of various gynecological conditions, including endometrial hyperplasia and cancer.
Measurement of Endometrial Stripe Thickness
- The measurement of endometrial stripe thickness can be performed by obstetrics and gynecology residents, but the accuracy of the measurement may vary depending on the level of experience 2.
- A study found that postgraduate year-4 residents correctly measured endometrial stripe thickness in 83% of cases, while lower-level residents were correct in 50% of cases 2.
- The most common error in measuring endometrial stripe thickness is an incorrect image plane, which was noted in 53% of attempts 2.
Clinical Significance of Endometrial Stripe Thickness
- An increased endometrial stripe thickness may be indicative of endometrial hyperplasia or cancer, particularly in postmenopausal women 3.
- A study found that the median endometrial thickness in postmenopausal women with benign histology was 7 mm, while it was 16 mm in those with precancerosis or malignancy 3.
- However, the thickness of the endometrium or polyp size in asymptomatic patients does not play a major role in the detection of endometrial cancer 3.