Pelvic MRI for Fibroids: The Most Reliable Diagnostic Method

What Are Uterine Fibroids?

Uterine fibroids are benign tumors that grow in and on the uterus and are the most common tumors of the female reproductive system. Approximately 70-80% of women experience fibroids during their lifetime and approximately 30-40% will seek treatment for unpleasant symptoms however, many women do not experience any symptoms at all.

Fibroids can be very small as the size of a tiny pearl or can grow to be very large as a pumpkin. A woman may have only one fibroid or many, and often they grow in clusters.
Fibroids can also enlarge the uterus similar to pregnancy and doctors will often use pregnancy terminology when describing the presence of uterine fibroids. For example, they may say the fibroids were so large and numerous that the abdomen was protruding, equivalent to a uterus at 16-weeks of pregnancy.

Detecting Uterine Fibroids

Most often, fibroids are detected during a woman’s annual pelvic exam by her OB-GYN. Once the diagnosis of fibroids is suspected, based on the physical exam and clinical findings, often the next step is to confirm this with an imaging study.

Because most Gynecologists have an ultrasound in their office or close proximity and ultrasound imaging is relatively inexpensive, this is often the first diagnostic tool used to confirm the presence of uterine fibroids.

Fibroids’ ultrasound appearance varies depending on the characteristics of the fibroid mass. Although you can see fibroids on an ultrasound, some of them can be mistaken for other conditions. A subserosal fibroid on an ultrasound or an exophytic fibroid could appear to be an ovarian tumor. An MRI would show uterine tumors and other uterine abnormalities and eliminate misdiagnosis.  That is why an MRI would be a better imaging test to determine if uterine fibroids are present.

How Is Pelvic Ultrasound Performed?

A pelvic ultrasound uses sound waves to create an image of the inside of the lower belly and projects it on a video monitor. Using an ultrasound, uterine fibroids can often be detected while the doctor views the bladder, uterus, cervix, and other reproductive organs on the video monitor. Pelvic ultrasounds can be done transabdominal or transvaginal depending on what the doctor wants to examine.

• Transabdominal ultrasound is performed with the patient lying on their back on the exam table. Warm gel is used on the lower abdomen to help improve the transmission of the sound waves. The doctor uses a special hand-held instrument called a transducer which is held to the abdomen and gently moved back and forth. The transducer sends a picture of the internal organs that can be seen from this view onto the screen.
• Transvaginal ultrasound is performed much like a pelvic exam with the patient lying on their back, knees bent, and legs supported by special footrests. A vaginal transducer is coated with gel and then placed in the vagina and moved around to create different views. The images show up on the video monitor in real-time for the doctor to read.

How Is MRI Scanning Better in Diagnosing Fibroids?

MRI scans utilize magnetic and radiofrequency waves to create high-resolution images of the pelvis. The level of detail provided is much greater than that of ultrasound and often identifies details that are not apparent on the ultrasound exam. Many patients that present with clinical findings of fibroids, including an enlarged uterus, have been misdiagnosed as having fibroids. However, uterus MRI images show it to be due to adenomyosis (see Example #3).

How Much Does An MRI Cost?

Historically, MRI imaging was cost-prohibitive and only used in certain situations. The cost of an MRI exam has come down dramatically over the past several years and, in most cases, is comparable to the cost of an ultrasound exam, particularly if the MRI is performed at an independent, i.e. non-hospital outpatient facility.

The cost of an MRI will vary depending on where the MRI is performed and what type of MRI you are receiving. The national average cost of an MRI in a hospital or inpatient facility is $2,250 and the same MRI averages $650 at an outpatient center.

What Does A Healthy Uterus Look Like?

The following 3 examples are pelvic MRI images from 3 different patients. They are all in the sagittal plane – side or profile view.

Example #1 – MRI of the Healthy Uterus

This example shows a normal uterus MRI image with no fibroids present. The uterus size is standard. The white line is the uterine cavity. The thin dark lines on either side of the cavity are the transition between the uterine lining and the muscular uterine wall (bright gray).

What Does A Uterus With Fibroids Look Like?

Example #2 – MRI of the Uterus with Fibroids

On this uterus MRI scan, note the enlarged uterus due to multiple fibroids which are black circles of different sizes.

What Does A Uterus With Adenomyosis Look Like?

Example #3 – MRI of the Uterus with Diffuse Adenomyosis

The uterus is enlarged up to the belly button (dark line at the upper left corner of the image). Note that the thin dark lines present in Example 1 are not seen and are replaced by very thick dark areas that surround the cavity (white line). Within these thick dark areas, there are innumerable white dots that are characteristic of cystic foci of diffuse adenomyosis.

How To Prepare For An MRI For Fibroids?

While some MRI examinations may require preparation beforehand or only scan you during a certain phase of your menstrual cycle, that is not necessary when scanning for the presence of fibroids.