Can Ultrasound Detect Endometriosis? What We Look For

Key Takeaways

1. Ultrasound is the recommended first-line imaging test for suspected endometriosis. It is widely available, lower in cost than MRI, and highly accurate for certain forms of the disease.

2. Transvaginal ultrasound detects ovarian endometriomas with sensitivity above 90%. These "chocolate cysts" are one of the clearest sonographic signs of endometriosis.

3. A normal ultrasound does not rule out endometriosis. Superficial lesions on the pelvic lining are often too small to see on any imaging, so your symptoms still matter even with a clear scan.

4. Diagnosis takes an average of 5 to 8 years in the United States. Accessible imaging is one way to shorten that timeline and get answers sooner.

5. A doctor's order is required, but you can pay out of pocket without waiting for insurance approval. Self-pay imaging means transparent pricing and no pre-authorization delays once you have your referral.

If you live with painful periods, pelvic pain between cycles, pain during intimacy, or unexplained fertility struggles, you may have already wondered about endometriosis. You are far from alone. The condition affects an estimated 1 in 10 women of reproductive age,¹ yet researchers estimate that as many as 60% of cases remain undiagnosed.² In the United States, it takes an average of 5 to 8 years from first symptoms to diagnosis.³

Part of that delay comes from how difficult endometriosis can be to confirm. Symptoms overlap with other conditions, and many patients are told their pain is normal long before anyone orders imaging. A pelvic ultrasound is often the first concrete step toward answers. It is generally noninvasive, requires no radiation, and can identify several forms of endometriosis along with other causes of pelvic pain.

At Nola Diagnostic Ultrasound in Metairie, we perform diagnostic pelvic ultrasounds for self-pay patients, which means you can get imaging without navigating insurance pre-authorization. Here is what an ultrasound can and cannot tell you about endometriosis, and exactly what our sonographers look for during your scan.

What Is Endometriosis?

Endometriosis is a chronic inflammatory condition in which tissue similar to the uterine lining grows outside the uterus. These lesions most often appear on the ovaries, the ligaments that support the uterus, and the lining of the pelvis. Less commonly, they can involve the bladder or bowel.

Because this tissue responds to hormonal cycles the way the uterine lining does, it can cause inflammation, scarring, and adhesions over time. Common symptoms include:

• Severe menstrual cramps that interfere with daily life

• Chronic pelvic pain, including pain between periods

• Pain during or after intercourse

• Painful bowel movements or urination, especially during your period

• Heavy menstrual bleeding

• Difficulty getting pregnant

Some people with extensive endometriosis have mild symptoms, while others with small amounts of tissue experience severe pain. That mismatch is one reason imaging plays such an important role in evaluation.

Can Ultrasound Detect Endometriosis?

Yes, ultrasound can detect certain forms of endometriosis, and it is considered the first-line imaging test when the condition is suspected. Its accuracy depends on the type of endometriosis present.

Clinicians and researchers generally group endometriosis into three forms, and each shows up differently on ultrasound:

Ovarian Endometriomas: Where Ultrasound Performs Best

Endometriomas are cysts on the ovaries filled with old blood, sometimes called "chocolate cysts." They have a distinctive appearance on ultrasound, often described as homogeneous with a ground-glass texture. Transvaginal ultrasound detects endometriomas with a sensitivity above 90% in published studies,⁴ making it a reliable way to confirm this form of the disease.

Deep Infiltrating Endometriosis: Detectable With a Careful Scan

Deep infiltrating endometriosis (DIE) refers to lesions that penetrate more than 5 millimeters beneath the pelvic lining, sometimes involving the uterosacral ligaments, bowel, or bladder. Research shows that a transvaginal ultrasound performed by an experienced sonographer is comparable to an MRI for assessing deep infiltrating endometriosis, at a fraction of the cost.⁵ Sonographers can also use a real-time technique called the "sliding sign" to assess whether pelvic organs move freely or are bound by adhesions.

Superficial Peritoneal Endometriosis: The Limitation to Know About

Superficial lesions sit on the surface of the pelvic lining and are typically too small and flat to appear on ultrasound or MRI. This is the most important limitation to understand: a normal ultrasound does not rule out endometriosis. If your scan is clear but your symptoms persist, that result is still useful information for your doctor, and further evaluation with a gynecologist may be the next step.

What We Look For During a Pelvic Ultrasound

A diagnostic pelvic ultrasound for suspected endometriosis is a systematic exam, and knowing what to expect can make the appointment feel less intimidating. During your scan, the sonographer evaluates:

The Uterus

We assess the size, shape, and position of the uterus. A uterus that is fixed in a tilted-back position can suggest adhesions. We also look for signs of adenomyosis, a related condition in which endometrial-like tissue grows within the muscular wall of the uterus. Adenomyosis frequently occurs alongside endometriosis and causes similar symptoms.

The Ovaries

The ovaries are examined for endometriomas and other cysts. We document the size, location, and internal characteristics of anything we find, which helps your physician distinguish an endometrioma from other types of ovarian cysts.

The Pelvic Structures and Surrounding Tissue

We evaluate the areas in front of and behind the uterus, including the pouch of Douglas, a space where deep endometriosis commonly develops. Checking whether organs slide freely against each other helps identify adhesions that lesions can cause.

Other Causes of Pelvic Pain

Endometriosis is one possibility among several. A pelvic ultrasound can also identify fibroids, ovarian cysts unrelated to endometriosis, and other structural findings that may explain your symptoms. Ruling conditions in or out is valuable either way.

Transvaginal vs. Abdominal Pelvic Ultrasound: Which Is Better for Endometriosis?

A transvaginal ultrasound, in which a slim probe is gently inserted into the vagina, provides much clearer images of the uterus and ovaries than an abdominal scan alone. For endometriosis evaluation, transvaginal imaging is strongly preferred because it places the probe closest to the structures being examined.

A transabdominal ultrasound, performed by moving a probe across the lower belly, may be used alongside a transvaginal exam or as an alternative for patients who decline the transvaginal approach. Your comfort matters, and the sonographer will explain each step and ask for your consent before beginning. 

Why Early Imaging Matters

The gap between first symptoms and diagnosis has real consequences. Studies link diagnostic delays to worsening pain, more emergency visits, higher healthcare costs, and reduced quality of life. Research also shows that reaching a correct diagnosis takes at least 7 visits to a health practitioner on average.⁶ If you have described your pain to multiple doctors without answers, that experience is common, and it is a reason to keep pushing for evaluation rather than a sign that nothing is wrong.

A pelvic ultrasound will not answer every question, but it moves the process forward. A positive finding gives your doctor concrete evidence to act on. A negative finding narrows the possibilities and can support a referral to a gynecologist or endometriosis specialist. Either outcome is better than another year of wondering.

As a self-pay imaging center, we offer transparent pricing with no surprise bills, and appointments are often available sooner than hospital-based imaging departments. 

Frequently Asked Questions

Can an ultrasound show endometriosis?

Yes, ultrasound can show certain forms of endometriosis, particularly ovarian endometriomas and deep infiltrating lesions. Transvaginal ultrasound detects endometriomas with sensitivity above 90%. However, superficial lesions on the pelvic lining usually cannot be seen on ultrasound, so a normal scan does not rule out the condition.

What does endometriosis look like on an ultrasound?

Endometriomas typically appear as cysts with a uniform, ground-glass appearance caused by old blood inside them. Deep infiltrating endometriosis can appear as nodules or thickened tissue along pelvic structures. Sonographers also check for indirect signs, such as organs that do not slide freely past one another, which suggests adhesions.

Do I need a referral for a pelvic ultrasound at Nola Diagnostic Ultrasound?

Yes. A doctor's order is required for a diagnostic pelvic ultrasound. If your provider suspects endometriosis or is investigating your pelvic pain, they can send us the order directly. Once we have it, you can schedule as a self-pay patient without waiting on insurance pre-authorization. 

What happens if my ultrasound is normal but I still have symptoms?

A normal ultrasound is useful information, but it is not the end of the road. Superficial endometriosis often does not appear on imaging, and definitive diagnosis sometimes requires laparoscopy, a minimally invasive surgical procedure. Bring your ultrasound report to a gynecologist and describe your symptoms in detail. Your images give your doctor a documented starting point.

Get Answers About Your Pelvic Pain

Pelvic pain that disrupts your life deserves investigation, and you should not have to wait years for answers. A diagnostic pelvic ultrasound is a safe, radiation-free first step that can identify endometriomas, signs of deep endometriosis, adenomyosis, fibroids, and other causes of pelvic pain.

Nola Diagnostic Ultrasound provides physician-interpreted diagnostic imaging for self-pay patients in the greater New Orleans area, with transparent pricing and convenient scheduling. 

If you or your doctor suspects endometriosis, ask them to send a pelvic ultrasound order. Don't have a doctor's order? You can book a quick telemedicine visit with NOWW Health to get one. Already have an order? Schedule your appointment today.

Sources

1. World Health Organization. "Endometriosis." https://www.who.int/news-room/fact-sheets/detail/endometriosis

2. Health Care for Women International (2024), scoping review on diagnostic delay. https://www.tandfonline.com/doi/full/10.1080/07399332.2024.2413056

3. Time to Diagnose Endometriosis: A Systematic Literature Review, PMC (2024). https://pmc.ncbi.nlm.nih.gov/articles/PMC11625652/

4. Transvaginal Ultrasound in the Diagnosis and Assessment of Endometriosis—An Overview, PMC (2022). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9777206/

5. Transvaginal Ultrasound vs. MRI: What Is the Optimal Imaging Modality for the Diagnosis of Endometriosis?, PMC (2023). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10604115/

6. Health Care for Women International (2024), scoping review on diagnostic delay. https://www.tandfonline.com/doi/full/10.1080/07399332.2024.2413056