Ultrasound of the Female pelvis Abnormal Uterine Bleeding: The Role of Ultrasound Holdorf Ultrasound of the Female pelvis

Contents Hormonal Regulation Follicle Stimulating hormone (FSH) Luteinizing Hormone (LH) Definitions Ovarian response to hormones Uterine response to hormones Abnormal Menstrual patters Contraception IUCD Oral Contraception

Female Physiology The ovarian and uterine phases of the menstrual cycle are ALWAYS tested on the boards!!!!

Hormonal Regulation The endometrium and ovaries respond to estrogen and progesterone levels in the blood. These levels are determined by a feedback mechanism between the ovaries and the hypothalamus/pituitary complex.

When serum estradiol levels fall below a given concentration, the hypothalamus produces gonadotropin releasing hormones (GnRH) which in turn signals the pituitary gland to secrete the pituitary gonadotropins: follicle stimulating hormone (FSH) and luteinizing hormone (LH).  

The hypothalamus and the pituitary

Follicle Stimulating Hormone Stimulates growth and development of ovarian follicles. As follicles grow, increasing estradiol levels within the follicles help them respond to LH with eventual ovulation. The follicles also produce estrogen which stimulates endometrial growth.

Luteinizing Hormone Stimulates maturation and ovulation of the Graafian follicle and subsequent development of the corpus luteum. Stimulates progesterone production which peaks after ovulation. When implantation of the conceptus occurs in the endometrium, hCG production signals the corpus luteum to continue secreting progesterone to prevent shedding of the endometrial lining. When implantation does not occur, decreasing progesterone levels permit sloughing of the uterine lining.

Definitions: Menstruation: the bleeding and shedding of the endometrial lining that occurs at approximately monthly intervals from menarche to menopause. Menarche: the onset of menses usually occurring between 11-14 years. Menopause: termination of regular menses usually occurring at 45-55 years. Premature Menopause: termination of regular menses prior to 40 years.

OVARIAN RESPONSE Under the influence of the pituitary hormones, the ovaries go through three specific phases during the normal cycle: Follicular phase Ovulatory phase Luteal Phase

Follicular phase DAYS 1-14 A varying number (usually 5-8) of follicles may be identified with EV Sonography in each ovary. The dominant follicle may by identified by about day 8 and measure approximately 10mm. Its size begins to exceed that of other follicles. Other sonographic considerations of a dominant follicle include: Any follicle measuring >11mm will most likely ovulate Grows linearly – Approx. 2-3mm per day Maximum diameter varies between 15-30mm Line of decreased reflectivity around follicle suggest ovulation will occur with 24 hours Presence of cumulus oophorus suggests ovulation will occur within 36 hours.(a scaring on the face of the follicle-via moving of the inner cell mass into the follicle)

Ovulatory phase –Day 14 Chronologically, ovulation occurs within 24- 36 hours after onset of the LH surge. Sonographic findings that ovulation has occurred may include: Sudden decrease in follicular size Free fluid in the cul-de-sac  

Luteal phase –Days 15-28 Involution (closing in on itself) of the ruptured Graafian follicle results in formation of a corpus luteum (yellow body). This structure produces progesterone which will maintain the Secretory endometrium should implantation occur. In the absence of hCG, the corpus luteum regresses after 14 days. Sonography my reveal: Replacement of dominant, cystic follicle with an echogenic structure representing thrombus Small, irregular cystic mass with low-level echoes Doppler findings of a hypervascular corpus luteum with low resistance flow.

Dominant Follicle on the ovary

1. Ovarian tissue 2. Follicle about to rupture 3 1. Ovarian tissue 2. Follicle about to rupture 3. Remains of the cumulus oophorus 4. The diameter of the follicle is of 22 mm

corpus luteum “Yellow body” A hormone-secreting structure that develops in an ovary after an ovum has been discharged but degenerates after a few days unless pregnancy has begun. A temporary endocrine structure in the ovaries that is involved in the production of relatively high levels of progesterone and moderate levels of estradiol. It secretes a moderate amount of estrogen to inhibit further release of gonadotropin-releasing hormone (GnRH) and thus secretion of luteinizing hormone (LH) and follicle- stimulating hormone (FSH). A new corpus luteum develops with each menstrual cycle.

UTERINE RESPONSE Menstruation is a catabolic response whereby the endometrial lining is shed if implantation of a conceptus has not occurred. The sonographic changes seen during menstrual cycle may be correlated with the histology of the various phases.

There are three phases Menstrual Phase (Days 1-5) Proliferative Phase (Days 6-14) Secretory Phase (Days 15-28)

Menstrual Phase The superficial layer of the endometrium become ischemic (looses blood supply), degenerates, sloughs off the basal layer and is expelled (menstruation). The pattern of menstrual bleeding is varied, but typically begins within 12-24 hours of heavy flow followed by scanty flow for 4-7 days.

Sonographic findings Thickened, echogenic endometrium prior to start of menses Complex appearance at beginning of menses Thin, slightly irregular endometrium after shedding of tissue maximum AP diameter (post menses) 2mm

A. Diagram showing development of the endometrium during the menstrual, proliferative, and secretory phases. In the menstrual phase, the endometrium appears as a thin, irregular interface. The central echogenicity arises from sloughed tissue and blood. In the proliferative phase, the endometrium is relatively hypoechoic. The central thin, echogenic line is a specular reflection from the endometrial surfaces. In the secretory phase, the endometrium achieves its maximum thickness and echogenicity. This appearance is from the distended and tortuous glands, which contain secretions. B. Postmenstrual, early proliferative endometrium. C. Periovulatory endometrium. A three-layered endometrium is seen: the collapsed endometrial lumen is demonstrated by the central echogenic line (thin arrow). D. Secretory endometrium

Proliferative Phase The re-growth of the endometrium is in response to estrogen released by ovarian follicles. The phase begins on the fourth or fifth day after the beginning of menses. It lasts about 10 days and ends at ovulation.  

Sonographic findings Hypoechoic area around prominent midline echo (early phase) Thickened, isochoric endometrium (late phase) Maximum AP diameter 6-8mm

Late proliferative phase endometrium

Proliferative Phase

Secretory Phase Although beginning at ovulation, no gross histologic changes can be observed in the endometrium early in the secretory phase. Progesterone mediates glandular enlargement of the endometrium, and the stroma becomes more vascular and edematous, resulting in an echogenic functional layer. In the absence of fertilization, implantation and hCG production, the glands fragment and undergo autolysis, starting the cycle again.

Sonographic findings Hyperechoic endometrium with obscured midline, often with posterior acoustic enhancement Maximum AP diameter up to 18mm

Secretory Endometrium

Abnormal Menstrual Patterns May be categorized as abnormalities of VOLUME or FREQUENCY

Hypermenorrhea (Menorrhagia) Excessive volume during cyclic menstrual bleeding Hypomenorrhea An abnormally small amount of menstrual bleeding Polymenorrhea Frequent menstrual bleeding occurring at less than 21 days apart Oligomenorrhea Menstrual bleeding occurring more than 35 days apart

Metrorrhagia Menometrorrhagia Dysmenorrhea Amenorrhea Irregular, frequent bleeding Menometrorrhagia Bleeding that is irregular in both frequency and volume Dysmenorrhea Painful bleeding Amenorrhea The absence of menstrual flow. Two categories: Primary-patient has never had a period Secondary-Patient had periods but they stopped

Dysfunctional uterine bleeding (DUB) Vaginal bleeding not related to pathology. Causes may be functional or organic and include: endocrine disorders, endometrial disorders, and many others. Even Stress.

Contraception Intrauterine Contraception Devices (IUDs) IUDs have been used as a method of contraception for approximately 40 years. Some women may even retain devices that were implanted many years in the past. All types are detectable by ultrasound, as they may be reflective and cast an acoustic artifact. Sonographers should be familiar with the most common types of IUDs: Copper-Coated 9Paraguard, Copper-T Safety Coil Lippe’s loop Hormonal

A sonogram is useful to confirm IUD position in the uterus, or to document myometrial penetration. If the IUD is not seen in the endometrial cavity or if perforation is suspected, an x-ray may help locate the device in the peritoneum. Sonographic findings Echogenic compared to endometrium Posterior acoustic shadow Positioned in mid-corpus or fundus

Types of Intrauterine Conception Devices

Normal Positioned IUCD

Copper T with US and X-ray

Normal Positioned IUCD

Abnormal Positon of an IUCD Copper T in the endocervical canal.

Abnormal Position of an IUCD The intrauterine device penetrates the posterior myometrium. Most of these malpositions occur at the time of lUCD insertion

Oral Contraceptive Pills (OCPs) Oral contraceptive pills are synthetic agents similar to natural female sex hormones that prevent conception by inhibiting ovulation. The most common regimen in the United States is a combined one in which pills containing both estrogen and progestin are taken every day for 20-21 days. Most patients on OCPs will not develop a dominant follicle and ovulate. However, EV imaging may reveal follicles in these patients, although they are smaller, measuring 5-19 mm

Often, endometrial growth is suppressed, so normal cyclic endometrial measurements will not be observed.   The endometrial appearance may assist in evaluating an appropriate therapeutic dosage of OCPs for patients with Dysfunctional Uterine Bleeding (DUB). Oral contraceptives many alter the normal sonographic appearance of both the uterus and ovaries.

Thin Endometrium of a patient who uses oral contraceptives.