TRANSVAGINAL ULTRASOUND

Gynecology Mini-Lectures for Students

TechniqueTransvaginal Ultrasound

Anatomy: Key Points The uterus does

NOT stand straight up in the coronal plane

It flops either forwards or backwards to lay on the bladder or on the rectumAnteverted/

retroverted

WRONG

RIGHT

Anatomy: Key Points The vaginal fornices

are very stretchy

Source: Lentz: Comprehensive Gynecology, 6th ed. 2012 Mosby. Figure 7-12.

In this image, the surgeons hand is INSIDE her vagina. See how much the anterior fornix can be stretched to perform bimanual massage of the uterusSource: aafp.org

fornices

Anatomy: Key Points The transvaginal ultrasound probe is

placed in the anterior or posterior fornix. This allows the probe to push up against the side of the cervix.

Anteverted uterus. Probe in anterior fornix. Retroverted uterus. Probe in posterior fornix.

Understanding ultrasound imagesThis is how you obtain a sagittal image of the uterus

PROBE

Understanding ultrasound images

Rotate probe 90 degrees to obtain a transverse image

PROBE

Understanding ultrasound images

As you can see from this image, it is impossible to obtain a “head-on” or “coronal” view of the uterus using normal transvaginal ultrasound. The probe would have to be outside the vagina.

vagina

PROBE

Understanding ultrasound images The “head-on” or “coronal” view of the

uterus can only be obtained by creating a 3D reconstruction of the sagittal and transverse images

AdvantagesTransvaginal Ultrasound

Advantages It is difficult to see

the pelvic organs from a trans-abdominal perspectivePubic bone creates

shadowsThere is a long

distance between probe and organs

Source: http://www.hopkinsmedicine.org/healthlibrary/GetImage.aspx?ImageId=161389

Advantages Transvaginal

probe is right next to uterusProbe has higher

frequency=better image resolution, lower penetration

Source: http://www.hopkinsmedicine.org/healthlibrary/GetImage.aspx?ImageId=161389

Transvaginal vs abdominal

These images are from the same patient. Notice the greater image resolution with transvaginal imaging. You can better delineate the endometrium, internal os, and character of the myometrium.

uterus

bladder

vagina

fundus

endometrium

cervix

ProcedureTransvaginal Ultrasound

Procedure Patient should empty her bladder Patient lays in lithotomy position Gel placed on ultrasound probe

Improves transmission of ultrasound waves Sterile probe cover placed on probe Gel placed over probe cover Patient or sonographer inserts probe Images obtained

Procedure The components of a typical gynecologic

sonographic examination include:Uterine size, shape, and orientationEvaluation of endometrium, myometrium, and cervixIdentification and morphology of ovaries, if possibleAssessment of the uterus and adnexa for masses,

cysts, hydrosalpinges, fluid collectionsEvaluation of the cul-de-sac for free fluid or massesNormal fallopian tubes usually cannot be seen during

pelvic sonography

Source: UpToDate, “Ultrasound examination in obstetrics and gynecology.”

Color flow Doppler color flow mapping uses different

colors to depict the direction of flow on a real-time color image

Useful to determine:Presence of flow

○ Rule out ovarian torsionVascularity of a mass

○ Characterize the massVascularity of the endometrium/myometrium

○ Distinguish benign versus malignant conditions

Color flow

Ovary with normal blood flow

Ovarian torsion (no flow)

Mass in endometrium. Color flow reveals multiple vessels=fibroid

Retained products of conception, demonstrated by increased flow to endometrium

IndicationsTransvaginal Ultrasound

Indications Gynecologic ultrasound examination has multiple uses,

including but not limited to:Evaluation of the menstrual cycle (endometrial thickness,

follicular development)Monitoring natural or stimulated follicular development during

infertility therapyLocalization of an intrauterine deviceEvaluation of abnormal uterine bleedingAssessment of a pelvic mass (eg, adenomyosis, fibroid, cancer,

cysts)Evaluation for sequelae of pelvic infection (eg, abscess,

hydrosalpinx)Evaluation of congenital uterine anomaliesScreening for malignancy

Source: UpToDate, “Ultrasound examination in obstetrics and gynecology.”