Does Endometriosis Show Up On Ct Scan and Fibroids: What to Know

September 13, 2025

Does Endometriosis Show Up on CT Scan and Fibroids: What to Know

If you’re dealing with pelvic pain, heavy periods, or fertility challenges, you may wonder whether a CT scan can reveal the cause—and specifically whether it can detect endometriosis or uterine fibroids. Here’s what to know about the strengths and limits of different imaging tests, how endometriosis and fibroids differ, and when each test is used.

Key takeaways

CT scans are not the preferred test to diagnose endometriosis and are only occasionally helpful for fibroids. Ultrasound and MRI are usually better tools.
Endometriosis is often diagnosed based on symptoms and exam, supported by ultrasound or MRI; laparoscopy remains the definitive diagnostic method when needed.
Ultrasound is the first-line imaging test for fibroids; MRI helps when detailed mapping is needed for treatment planning.
CT uses ionizing radiation. Ultrasound and MRI do not.

Endometriosis vs. fibroids: what’s the difference?

Endometriosis occurs when tissue similar to the uterine lining grows outside the uterus—commonly on the ovaries, pelvic peritoneum, and sometimes the bowel or bladder. It can cause painful periods, pelvic pain between periods, pain with sex, and infertility. The Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD/NIH) and ACOG note that diagnosis is based on symptoms, pelvic exam, and imaging when helpful; laparoscopy can confirm the diagnosis when needed.

Uterine fibroids (leiomyomas) are benign muscular tumors in or on the uterus. They can cause heavy or prolonged periods, pelvic pressure, frequent urination, and fertility or pregnancy issues. ACOG and NIH indicate that most fibroids are found with a pelvic exam and confirmed by ultrasound.

Will a CT scan show endometriosis?

In most cases, no. A standard CT scan of the abdomen and pelvis is not sensitive for detecting endometriosis. It may miss implants and adhesions, which are typically small, flat, and best visualized surgically or with specialized imaging. CT might incidentally show large ovarian endometriomas or complications (for example, bowel obstruction), but it is not recommended as a first-line test to evaluate suspected endometriosis.

Why? CT provides excellent views of organs and can detect many conditions, but endometriosis lesions—especially superficial or small deep lesions—often look similar to surrounding tissues on CT. As a result, CT frequently appears normal even when endometriosis is present.

What imaging tests work better for endometriosis?

Transvaginal ultrasound (TVUS): Widely available, radiation-free, and often the first imaging test. It can identify ovarian endometriomas (a type of endometriosis cyst on the ovary) and may detect some deep lesions when performed by experienced sonographers.
MRI: Particularly helpful for deep infiltrating endometriosis involving the bowel, bladder, uterosacral ligaments, or rectovaginal septum, and for complex cases. MRI provides superior soft-tissue contrast without ionizing radiation.
Laparoscopy: A minimally invasive surgery that allows direct visualization and treatment of lesions. ACOG notes that clinicians can start empiric treatment based on symptoms and exam without surgery, but laparoscopy remains the definitive diagnostic option when confirmation or surgical treatment is required.

Will a CT scan show fibroids?

Sometimes, but it’s not the preferred test. Many fibroids are visible on CT if they are large or calcified. However, CT is usually ordered for other reasons (e.g., emergency evaluation), not to diagnose fibroids. For targeted fibroid evaluation, clinicians typically choose ultrasound first, followed by MRI if more detail is needed.

Best imaging tests for fibroids

Ultrasound (abdominal and transvaginal): The first-line test recommended by professional societies such as ACOG. It can show the number, size, and location of fibroids and distinguish them from other causes of uterine enlargement.
MRI: Useful for detailed mapping (especially before uterine fibroid embolization or myomectomy), evaluating the blood supply, and distinguishing fibroids from other masses. MRI is also helpful when the uterus is large or the ultrasound view is limited.
Sonohysterography or hysteroscopy: If heavy bleeding suggests a fibroid within the uterine cavity (submucosal), these approaches can help identify and treat intracavitary lesions.

Why CT isn’t first choice: radiation and diagnostic yield

CT scans use ionizing radiation. The U.S. Food and Drug Administration (FDA) explains that while the risk from a single appropriate CT scan is low, radiation should be used judiciously and only when it will change management. Because ultrasound and MRI provide better information for most gynecologic questions without radiation, they are preferred for evaluating suspected endometriosis or fibroids.

When to consider imaging—and which one

Symptoms suggesting endometriosis: painful periods, chronic pelvic pain, pain with sex, bowel or bladder pain during periods, or infertility. Start with a thorough history and pelvic exam. Your clinician may order transvaginal ultrasound, and in complex cases or when deep endometriosis is suspected, MRI.
Symptoms suggesting fibroids: heavy or prolonged menstrual bleeding, anemia, pelvic pressure, frequent urination, constipation, or pregnancy challenges. Transvaginal and/or pelvic ultrasound is typically first. MRI is added for pre-surgical planning or when ultrasound is inconclusive.

What to expect from each test

Transvaginal ultrasound: A thin probe is placed in the vagina to obtain images. It’s generally well tolerated, takes about 15–30 minutes, and requires no radiation or contrast.
MRI: You’ll lie still in a scanner for 30–60 minutes. Contrast may be used. No ionizing radiation. Inform the team about implants or devices.
CT: Quick (minutes), sometimes with iodinated contrast. Uses ionizing radiation. Usually not ordered solely to evaluate endometriosis or fibroids unless assessing complications or alternative diagnoses.

Treatment implications

Imaging helps tailor treatment:

Endometriosis: Options include pain management, hormonal therapies (e.g., combined hormonal contraceptives, progestins, or GnRH analogs/antagonists), and laparoscopic surgery for diagnosis and treatment when needed. ACOG supports empiric therapy based on symptoms in many cases.
Fibroids: Options include watchful waiting, medications to control bleeding or shrink fibroids, uterine-preserving procedures (e.g., uterine fibroid embolization, myomectomy), or hysterectomy. MRI mapping can guide procedure choice and approach.

When to seek care

See a clinician if pain disrupts your daily life, periods are very heavy (soaking through pads/tampons hourly for several hours), you have symptoms of anemia (fatigue, dizziness), or you’re having difficulty conceiving. Early evaluation can reduce complications and expand treatment options.

Bottom line

A CT scan is rarely the right test to look for endometriosis and only occasionally helpful for fibroids. For most people, ultrasound—and sometimes MRI—provides the clearest answers without radiation exposure. Work with your clinician to choose the least invasive test that will most effectively guide your care.

Trusted sources and further reading

ACOG: Endometriosis — https://www.acog.org/womens-health/faqs/endometriosis
ACOG: Uterine Fibroids — https://www.acog.org/womens-health/faqs/uterine-fibroids
NICHD/NIH: What is endometriosis? — https://www.nichd.nih.gov/health/topics/endometriosis
NIH MedlinePlus: Uterine fibroids — https://medlineplus.gov/uterinefibroids.html
FDA: What are the radiation risks from CT? — https://www.fda.gov/radiation-emitting-products/medical-x-ray-imaging/what-are-radiation-risks-ct

This article is for educational purposes and does not replace personalized medical advice. Always consult your clinician for diagnosis and treatment options right for you.