Chapter 40: The Sonographic and Doppler Evaluation of the Female Pelvis

translabial

across, or through, the labia

transperineal

across, or through, the perineum

introitus

an opening or entrance into a canal or cavity, as the vagina

cornu, cornua

any projection like a horn; refers to the fundus of the uterus where the fallopian tube arises

sonohysterography

(saline infused sonography, or SIS) technique that uses a catheter inserted into the endometrial cavity, with the insertion of saline solution or contrast medium, to fill the endometrial cavity for the purpose of demonstrating abnormalities within the cavity or uterine tubes

the layer of endometrium that represents the thin surrounding hyperechoic outermost echo is the ___layer

basalis

retroverted

bending backward

Before a pelvic ultrasound, what pertinent information should be requested from the patient?

A complete history is critical to adequately correlate ultrasound findings with the proper differential. It is important for the sonographer to use a routine patient questionnaire requesting the following information: last menstrual period, gravidity, parity, physiologic menstrual status, hormone regimen, symptoms, history of cancer, family history of cancer, past surgeries, laboratory tests, pelvic examination findings, and previous ultrasound findings.

menstruation

days 1 to 4 of the menstrual cycle; the endometrial canal appears as a hypoechoic central line representing blood and tissue

proliferative phase (late)

days 10 to 14 of the menstrual cycle; ovulation occurs; the endometrium increases in thickness and echogenicity

secretory (luteal) phase

days 15 to 28 of the menstrual cycle; the endometrium is at its greatest thickness and echogenicity with posterior enhancement

proliferative phase (early)

days 5 to 9 of the menstrual cycle; endometrium appears as a single thin stripe with a hypoechoic halo encompassing it; creates the "three-line sign"

the full bladder____the bowel and it's contained gas from teh field of view and ____the anteflexed uterus slightly so that it's more perp. to the transducer angle

displaces;flattens

the postmenopausal endometrial complex is seen as a thin____line measuring less than 8mm unless hormones are being used

echogenic

during menstuation the____canal appars as a hypoechoic central line representing blood and tissue reaching 4-8 mm including the basal layer

endometrial

the ____ of the uterus is hypoechoic and surrounds the relatively echogenic endometrial stripe, creating a subendometrial halo

endometrium

the axis of the uterine body relative to the cervix if referred to______

flexion

the best way to identify an ovary is a____

follicular cyst

the layer that is seen as a hyperechoic halo encompassing the stripe is the ___layer

functionalis

as menses progress, the hypoechoic echo that represented blood disappears and the endometrial stripe is a thin________line that is usually 2-3 mm long

hyperechoic

the ____vessels can be used as a landmark to identify the lateral adnexal borders

iliac

endometrium

inner lining of the uterine cavity, which appears echogenic to hypoechoic on ultrasound, depending on the menstrual cycle

internal os

inner surface of the cervical os

typicall the ovary is located___ to the uterus and ___to the internal iliac vessells which can be used as a landmark

lateral;anterolateral

these measurements of the uterus and ovaries must be documented

length;width and axial measurements

the muscle that is best visualized in the transverse plan at the most inferior aspect of the bladder is the__________muscle

levator ani

myometrium

middle layer of the uterine cavity that appears very homogeneous with sonography

Sonographically, sections of the_____muscle are seen at the posterior lateral corners of the bladder at the level of the vagina and cervix

obturatur internus

Parity

pregnancy

coronal plane

refers to a horizontal plane through the longitudinal axis of the body to image structures from anterior to posterior

Describe the proper endovaginal transducer preparation before each examination.

After the transducer has been soaked in a Cidex-type solution for at least 10 minutes, it is important to rinse off the transducer with water and dry it before applying the coupling gel and protective condom. Careful examination for air trapped under the condom and subsequent removal prevents artifacts. The final step of transducer preparation is adding sterile lubrication to the outer surface. If the examination is performed on an infertility patient, the use of water to lubricate the transducer is preferred, because water does not have a negative effect on sperm mobility.

What are the contraindications for endovaginal ultrasound?

Contraindications include patient refusal, lack of patient tolerance (usually secondary to intense pelvic pain), and age (both premenarche and menopausal). Evaluation with endovaginal scanning is exempted with patients who have an intact hymen or small vaginal canal.

Describe the changes of the endometrium throughout the normal menstrual cycle.

During menstruation (days 1-4), the endometrium appears as a hypoechoic central line representing blood and tissue. This is surrounded by a hyperechoic endometrial echo. If menstrual flow is heavy, the entire endometrial cavity can appear anechoic. During this phase of early menses, acoustic enhancement posterior to the endometrium may appear as it does in the luteal phase, but to a lesser degree. As menses progress (days 3-7), the hypoechoic echo that represented blood disappears.In the proliferative phase (days 5-9) the endometrium appears as a single thin stripe (the endometrial cavity) with a hypoechoic halo (the functionalis) encompassing it, creating the three-line sign. The thin surrounding hyperechoic layer of endometrium represents the basalis. In the early secretory phase (days 10-14), ovulation occurs. The endometrium increases in thickness and echogenicity, representing the basalis that progresses and inundates the entire endometrium.During the luteal or secretory phase, the endometrium is at its greatest thickness and echogenicity with posterior enhancement. The posterior enhancement is thought to be attributable to the increased vascularity of the endometrium.

In a normal anteflexed uterus, visualization of the cervix is optimized by what angulation of the endovaginal transducer?

Endovaginal evaluation of the cervix and rectouterine recess is superior to the transabdominal technique. While inserting or withdrawing the transducer into or from the vaginal fornix about 2 to 3 cm from the external os, the cervix is posterior to the anechoic bladder. Improved visualization may require posterior angulation if the uterus is anteverted and anterior angulation if the uterus is retroverted.

If fluid is present within the endometrial cavity, how should the endometrial thickness be determined?

Fluid within the endometrial cavity is excluded from the measurement. Measure the anterior and posterior layers separately and add the two measurements together to determine the thickness.

What are the four major muscle groups in the female pelvis that are visualized by ultrasound?

In the lesser or true pelvis, the iliopsoas, reproductive organs, levator ani, and obturator internus muscles can be identified.

the muscles that are located on either side of the midline posterior to the upper half of the uterine body and fundus are the ______muscles

Piriformis

Describe the sonographic technique to image the ovary.

Sonographically, the normal ovary appears as an ovoid homogeneous echodensity; follicular cysts are often present. The best sonographic marker for the ovary is identification of a follicle within the almond shaped structure and the iliac vessels (the ovary lies anterior and medial to the vessel).

How is the uterus properly measured?

The TA technique is the best way to measure the cervical-fundal dimension of the uterus in the longitudinal plane. Oblique angulation may be needed to elongate and measure the entire length of the longitudinal plane of the uterus. Its length is always measured from the distal end of the fundus to the distal end of the cervix. Either the TA or TV scanning technique may be used to measure the width and anteroposterior dimensions of the uterus. Because of the proximity of the uterus to the broad ligament and surrounding vessels, it may be difficult to delineate the lateral borders of the uterus. Color Doppler or changing postprocessing controls may help delineate these borders.

What is the best landmark for orientation in the female pelvis when using endovaginal sonography?

The best landmark for orientation in the female pelvis with endovaginal ultrasound is the uterus.

What is the best way to visualize the rectus abdominis muscles? How do they appear sonographically?

The best way to image the rectus abdominis muscles is with a transabdominal scan across the transverse plane of the pelvis. These muscles are symmetric and superficial in the abdominal wall.

How is the endometrium properly measured?

The endometrial thickness is measured from the highly reflective interface of the endometrium and myometrium in the sagittal view. This sonographic measurement includes both the anterior and posterior layers of the endometrium. The surrounding hypoechoic area and fluid within the endometrial cavity are not included in the measurement.

In an endovaginal examination of the pelvis, describe how the transducer should be angled to image the fundus of the uterus and cervix.

The handle of the transducer should be pushed downward (toward the bed) to best image the fundus of the uterus. If shadowing is seen, the transducer should be gently rocked side to side to eliminate air interference that may be causing the air pockets and shadowing to occur. To image the cervix of the uterus, slightly withdraw the transducer and angle the handle of the transducer upward.

Why is it important to know the last menstrual period before beginning the ultrasound examination?

The last menstrual period helps the sonographer determine if the size of the uterus, endometrium, and ovaries are appropriate for the particular part of the menstrual cycle the patient is in.

What blood vessels are routinely visualized within the myometrium of the uterus?

The myometrium of the uterus should have a homogeneous echotexture with smooth-walled borders. Any areas of increased or decreased echotexture should be noted and measured. The normal arcuate vessels often are seen in the periphery of the uterus and should not be mistaken for pathology. These vessels bifurcate into radial branches, which supply blood throughout the uterus. These vessels are most often demonstrated 1 to 3 weeks after onset of the last menses. Just before the onset of menses and during menses, these vessels are less apparent. The vasodilating actions of estrogens on the uterus during midcycle and the vasoconstricting hormonal influences during the late luteal phase before menses explain the normal dynamic changes of these vessels.

How is the ovary measured?

The ovary is measured in the sagittal or longitudinal plane at its longest length and anteroposterior dimension. In transverse or coronal scans, the width is measured at the widest point.

What are the best landmarks to use to image the ovaries with ultrasound?

The sonographer could begin to image the ovaries by scanning the fundus of the uterus and angling the transducer to the right or left adnexal area. The iliac vessels are usually posterior to the ovaries. If follicular cysts are present along the periphery of the ovary, the structure is easier to image.

the thickness of the endometrium should be measured in which plane?

saggital

during the ____phase the endometrium is at it's greatest thickness and echogenicity with posterior enhancement

secretory

in the early proliferative phase (days 5-9) the endometrial canal appars as a ___ stripe

single

arcuate vessels

small vessels found along the periphery of the uterus

menarche

state after reaching puberty in which menses occur normally every 21 to 28 days

adnexa

structure or tissue next to or near another related structure; the ovaries and the fallopian tubes are in the adnexa of the uterus

premenarche

time before the onset of menses

anteverted

tipped forward

The best way to measure the cervical fundal dimension is of the uterus in the longitudinal plane is the__________technique

transabdominal

a distended bladder typically has a ___or elongated shape on midline scans

triangular

___refers to the axis of the cervix relative to the vagina

version

What are the three anatomic areas of the uterus?

The three anatomic areas of the uterus are the cervix, body, and fundus.

What three layers compose the uterus?

The three layers of the uterus are the endometrium, myometrium, and serosal layer.

What is the purpose of a full bladder when using the transabdominal scanning technique?

The transabdominal technique requires the urinary bladder to be adequately filled. Instruction should be given to the patient to drink at least 32 oz of fluid 1 hour before examination time and not to empty her bladder before the scheduled appointment. The full bladder displaces bowel and "flattens" the anteflexed uterus slightly so it is more perpendicular to the transducer angle. The distended bladder also becomes an acoustic window to view pelvic anatomy and pathology. The bladder is considered optimally full when it covers the fundus of the normal-sized uterus, although an overdistended bladder may compress, distort, and displace anatomy beyond the focal zone of the transducer.

Describe the placement of the transducer to properly record spectral Doppler of the uterine and ovarian arteries.

The uterine artery is best demonstrated with Doppler as the transducer is angled toward the fundus of the uterus. The ovarian flow is best demonstrated as the transducer is angled lateral to the ovary.

What is the best landmark for the ovary?

To better characterize the ovary and its contents and to visualize those ovaries that are nonvisible transabdominally, endovaginal scanning is superior. Typically, the ovary is located just lateral to the uterus and anteromedial to the internal iliac vessels, which can be used as a landmark to localize the ovary. Use the contralateral side of the bladder as a window when scanning transabdominally. Endovaginally, the ovaries are easiest to locate in the coronal plane lateral to the cornua. However, it is not uncommon to find the ovaries located above the uterus or posterior in the rectouterine cul-de-sac area.

When using the endovaginal scanning technique, what labeling terms are used to represent the scanning planes?

When inserting the transducer in the sagittal plane, the flat part of the transducer is along the top surface of the handle so the beam is projected in the midline anteroposterior aspect of the body. This is termed sagittal. From the sagittal plane, the transducer is limited in motion because of the vagina.True parasagittal planes are never obtained, but angulation from this central point is considered sagittal imaging. The transducer is then rotated 90 degrees counterclockwise to obtain coronal images.