Gynecology Mini-Lectures for Students Transvaginal ultrasound
Transvaginal Ultrasound Technique
Anatomy: Key Points WRONG • 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 rectum • Anteverted/retroverted right
Anatomy: Key Points • The vaginal fornices are very stretchy fornices 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 uterus Source: aafp.org
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. Retroverted uterus. Probe in posterior fornix. Anteverted uterus. Probe in anterior fornix.
Understanding ultrasound images This is how you obtain a sagittal image of the uterus PROBE
Understanding ultrasound images PROBE Rotate probe 90 degrees to obtain a transverse image
Understanding ultrasound images vagina PROBE 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.
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
Transvaginal Ultrasound Advantages
Advantages • It is difficult to see the pelvic organs from a trans-abdominal perspective • Pubic bone creates shadows • There 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 uterus • Probe has higher frequency=better image resolution, lower penetration Source: http://www.hopkinsmedicine.org/healthlibrary/GetImage.aspx?ImageId=161389
Transvaginalvs abdominal cervix fundus bladder endometrium uterus vagina 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.
Transvaginal Ultrasound Procedure
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 orientation • Evaluation of endometrium, myometrium, and cervix • Identification and morphology of ovaries, if possible • Assessment of the uterus and adnexa for masses, cysts, hydrosalpinges, fluid collections • Evaluation of the cul-de-sac for free fluid or masses • Normal 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 torsion • Vascularity of a mass • Characterize the mass • Vascularity of the endometrium/myometrium • Distinguish benign versus malignant conditions
Color flow Mass in endometrium. Color flow reveals multiple vessels=fibroid Ovary with normal blood flow Retained products of conception, demonstrated by increased flow to endometrium Ovarian torsion (no flow)
Transvaginal Ultrasound Indications
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 therapy • Localization of an intrauterine device • Evaluation of abnormal uterine bleeding • Assessment of a pelvic mass (eg, adenomyosis, fibroid, cancer, cysts) • Evaluation for sequelae of pelvic infection (eg, abscess, hydrosalpinx) • Evaluation of congenital uterine anomalies • Screening for malignancy Source: UpToDate, “Ultrasound examination in obstetrics and gynecology.”