Ch.42 Sonographic and Doppler Evaluation of the Female Pelvis

uterus: sonographically

Uterine muscle consists of three layers; outer serosa of uterus not visualized sonographically. Middle layer of uterus is the myometrium. This layer should have homogeneous echotexture with smooth-walled borders. Any areas of increased or decreased echotexture should be noted and measured.

During menstruation

- (days 1 to 4), endometrial canal appears as hypoechoic central line representing blood and tissue and reaching 4 to 8 mm, including basal layer. - Surrounded by hyperechoic basal endometrial echo -If menstrual flow heavy, entire endometrial cavity can appear anechoic.

Ovaries sonographically

-Sonographically, normal ovary appears as an ovoid medium-level echogenic structure. -Follicular cysts may be seen peripherally in cortex. -Appearance changes with age and menstrual cycle.

Arcuate arteries

calcification may be seen in the arteries in postmenopausal women and appear as peripheral linear echoes with shadowing. This is normal aging process that may be associated in diabetic patients.

Uterus seperated

-Body separated from cervix by isthmus at level of internal os and identified by narrowing of canal -Tissue echogenicity surrounding cervical canal should appear homogeneous.

Muscles of the pelvis

-Rectus abdominis muscles insert on pubic rami and are paired parasagittal straps in abdominal wall. -Appear as hypoechoic structures with echogenic striations -Rectus sheath separates sonographic appearance of rectus abdominis muscle from surrounding fat and bowel as a bright linear echogenic reflector.

Endometrium sonographically

-Sonographic appearance of endometrial canal seen as thin echogenic line -Result of specular reflections from interface between opposing surfaces of endometrium -Consists of superficial functional layer and deep basal layer

Coccygeus and piriformis muscles: Muscle of the pelvis

-are located deep, cranially, and posteriorly. No routinely visualized. -The piriformis muscles are located on either side of the midline posterior to upper half of the uterine body and fundus. This is the most common muscle to be mistaken for the ovary.

Rectouterine recess (posterior cul-de-sac)

-is most posterior and inferior reflection of peritoneal cavity. - Located between rectum and vagina; also known as pouch of Douglas - Posterior cul-de-sac frequently initial site for intraperitoneal fluid collection

3D ultrasound

-now accepted additional technology in ultrasound - Allows imaging from volume sonographic data rather than conventional planar data

Dystrophic calcification

Echogenic foci in the inner layer of the myometrium, which are usually nonshadowing, are thought to represent a calcification related to previous instrumentation.

Levator ani muscles: Muscle of the pelvis

best visualized sonographically in transverse plane with caudal angulation at most inferior aspect of bladder. Hypoechoic, hammock-shaped area that is medial, caudal, posterior to obturator internus.

Normal fallopian tube

can be difficult to identify by transabdominal or transvaginal sonography unless surrounded by fluid or filled with fluid (dilated).

Sonohysterography

also known as saline infused sonography (SIS) or hysterosonography -Involves instillation of sterile saline solution into endometrial cavity -- Is used to further evaluate endometrium when it exceeds normal thickness or shows focal areas of thickening and polyps suspected

Ovaries

Are very mobile and can move considerably in pelvis, depending on bladder volume and whether woman has had previous pregnancy Uterine location influences position of ovaries. Are elliptical in shape, with long axis usually oriented vertically Transvaginal scanning is superior for characterizing texture of ovary

Uterus endometrium: sonographically

Inner layer of uterus is endometrium. Layer thin, compact, relatively hypovascular Hypoechoic and surrounds relatively echogenic endometrial stripe, creating subendometrial halo Thin outer layer separated from intermediate layer by arcuate vessels

Phase of early menses

- acoustic enhancement posterior to endometrium may appear. - As menses progress (days 3 to 7), hypoechoic echo that represented blood disappears and endometrial stripe is discrete thin hyperechoic line, usually only 2 to 3 mm.

Early proliferative phase

-(days 5 to 9), endometrial canal appears as single thin stripe. -Functionalis layer seen as hyperechoic halo encompassing it -Basalis layer of endometrium represents the thin surrounding hyperechoic outermost echo. -This complex creates three-line sign. -Early in proliferative phase (days 5 to 9), endometrial complex thin, measuring 6 mm -Becomes thicker, 10 mm, from days 10 to 14 before ovulation -Thin surrounding hyperechoic layer of endometrium represents innermost layer of myometrium; is not included in measurement -In later proliferative phase (days 10 to 14), ovulation occurs.

Iliopsoas muscles: Muscle of the pelvis

-Can be seen in greater pelvis. -Is a combination of the iliacus muscle and the psoas major. -Courses anterolaterally to its insertion on the lesser trochanter of the femur.

Nobthian cyst

-Can frequently visualize cervical inclusion cysts (___________cysts) near endocervical canal These cysts are generally <1-2 cm wide; are anechoic smooth-walled structures with acoustic enhancement posteriorly Of no clinical significance and generally not measured

Cervix

-Cervix fixed in midline, but uterine body mobile and may lie obliquely on either side of midline -Flexion refers to axis of uterine body relative to cervix; version refers to axis of cervix relative to vagina. -Uterus is usually anteverted and anteflexed. - Uterus may also be retroflexed when body tilted posteriorly or retroverted when entire uterus tilted backward.

Secretory phase

-During secretory (luteal) phase (days 15 to 28), endometrium at greatest thickness and echogenicity, with posterior enhancement - Posterior enhancement thought to be attributable to increased vascularity of endometrium -Functionalis layer becomes isoechoic with basalis layer. -Endometrial complex measures 7 to 14 mm during secretory phase. --Endometrial thickness measured from highly reflective interface of basalis layer of endometrium and myometrium in sagittal view.

Rectouterine Recess and Bowel

-Gas and fluid-filled bowel loops are poorly defined, echo-free mobile structures that usually demonstrate peristalsis under observation. -Solid material in bowel hyperechoic and may produce shadowing, as does gas -Empty bowel can look like irregular bull's-eye with thin, sharp, hypoechoic outline on cross section.

Obturator Internus muscle: Muscle of the pelvis

-In lesser or true pelvis, the urinary bladder, reproductive organs, levator ani, obturator internus muscles are identified. -Sonographically, sections of obturator internus muscle are seen at posterior lateral corners of bladder at level of vagina and cervix. -Muscle is hypoechoic, ovoid, surrounded by obturator fascia, and serves as tendinous attachment for levator ani muscle.

Arcuate vessels in uterus

-Normal vessels often seen in periphery of uterus and should not be mistaken for pathology -Radial arteries arise as multiple branches from arcuate arteries and travel centrally to supply rich capillary network in deeper layers of myometrium and endometrium. -These vessels are most often demonstrated between 1-3 weeks after the onset of last menses. -Just before of menses and during menses these vessels are less apparent.

Ovaries are located

-Ovary is located just lateral to uterus and anteromedial to internal iliac vessel, which can be used as landmark to localize the ovary. Transvaginally, the ovaries are easiest to locate in coronal plane lateral to the cornua. Not uncommon to find ovaries located above uterus or posterior in rectouterine cul-de-sac area