Topic Review

Practical ultrasonography in obstetrics and gynecology

2010-03-30R3 이진영

IntroductionI. Method of pelvic ultrasonography

I. Transvaginal and transabdominal methodII. Practice Guideline for Pelvic US

II. Ultrasonography in obstericsI. Emergency sonography II. Early pregnancyIII. Biometry; CRL, BPD, FL, ACIV. Nuchal translucency

III. Ultrasonography in gynecologyI. Emergency sonographyII. Pathology - Uterus - Ovary

I. Method of pelvic ultrasonography

I. Transvaginal and transabdominal method

II.Practice Guideline for Pelvic US

I. Pelvic ultrasonographyMethod Transabdominal(TA) Transvaginal(TV)

Field size Large -Relationship of ovaries to uterus-Large masses

Limited -Large masses may be beyond focal zone-No entire uterine

Flexibility -Upper abdomen with same transducer-Bladder, distal ureters

Must use TA transducer for upper abdomenBladder not well seen

Invasive na-ture

Non-invasiveTechnique of choicefor paediatrics & others

InvasivePt/sonographercommunica-tionPrivacy essential

Preparation Full bladder Empty bladder

Resolution Limited resolution espe-cially in far field

Superior to TA

TA pelvic ultra-sound

Transverse

TA pelvic ultra-sound

Saggi-tal

TV pelvic ultrasound

Coronal or trans-verse

Probe marker towards patient’s RIGHT

TV pelvic ultrasound

Saggi-tal

Probe marker towards ceiling

Organ Anatomy

VaginaMid-line, thin walled, muscular structure 8-9 cm in lengthFrom uterus to vestibule

Uterus Midline

Pear-shaped muscular hollow organ

Anterior to rectum pos-terior to bladder

Adult uterus Length 7cm, wide 4

cm and AP diameter 3 cm

Organ Anatomy

Organ Anatomy

Uterus

Version: axis of cervix to vaginaFlexion: axis of uterus to cervix

Organ Anatomy

UterusEndometrium

Menstruation

Regenerative/ early proliferative

proliferative

Peri-ovulatory

Secretory

Organ Anatomy

Ovary Posterior and lateral to either side of uterusCentral medulla & outer stroma(follicles)

II. Practice Guideline for Pelvic US

Indications1. Pelvic pain2. Dysmenorrhea3. Amenorrhea4. Menorrhagia5. Metrorrhagia 6. Menometrorrhagia 7. F/up of a previously abnormality8. Evaluation, monitoring, and/or treatment of infertility patients9. Delayed menses, precocious pu-

berty, or vaginal bleeding in prepubertal

child10. Postmenopausal bleeding

The American Institute of Ultrasound in Medicine, 2009

11. Abnormal or technically limited pelvic examination12. Signs or symptoms of pelvic infec-tion13. Further characterization of a pelvic abnormality noted on another imag-ing 14. Evaluation of congenital anomalies15. Excessive bleeding, pain, or signs of infection after pelvic surgery, deliv-ery, or abortion16. Localization of IUD17. Screening for malignancy in pa-tients at increased risk18. Urinary incontinence or pelvic or-gan prolapse19. Guidance for interventional or sur-gical procedures

UterusReference points for other pelvic structures

(1) Uterine size, shape, and orientation (2) Endometrium (3) Myometrium (4) Cervix (5) IUD: location (6) Vagina: landmark for cx & lower uterine seg-

ment

Practice Guideline for Pelvic US

Adnexa (Ovaries and Fallopian Tubes)First! Identify ovaries Major point of reference for assessing

pathology Size, 2 orthogonal planes Not identifiable in some females

– Prior to puberty, after menopause, large myomatous uterus

Normal fallopian tubes: not commonly identi-fied

Adnexal abnormality Relationship to ovaries and uterus

Practice Guideline for Pelvic US

Cul-de-sacPresence of free fluid or massMass: size, position, shape, characteristics, &

relationship to ov. and uterus

Differentiation of normal bowel from mass : Transvaginal exam. may be helpful

Practice Guideline for Pelvic US

II. Ultrasonography in ob-sterics

I. Emergency sonography II. Early pregnancy

III. Biometry; CRL, BPD, FL, ACIV. Nuchal translucency

Ectopic Pregnancy

Common cause of morbidity & mortality in childbearing age

Positive findings on pregnancy test Particularly, HCG < behind the estimated GA

Common sonographic findings Cystic or solid adnexal mass Dilated & thick-walled fallopian tube Low echogenic or lucent intraperitoneal fluid Hematosalpinx & extrauterine G-sac containing

yolk sac +/- an embryo

Color-flow Doppler: trophoblastic Doppler flow

I. Emergency sonography

Ectopic Pregnancy

Decidual cast or pseudogestational sac Intrauterine fluid collection Single decidual layer

Cervical pregnancy -Must distinguish from abortion in progress

Round or oval noncrenated sac Fetal cardiac activity, constant sac shape &

loc. Closed internal os

36-year-old woman with tubal ectopic pregnancy after artificial insemination

26-year-old woman with live tubal ectopic pregnancy : ring of fire sign of trophoblastic flow

22-year-old woman with live right-sided tubal ectopic preg-

nancy

Concomitant intrauterine and ec-topic pregnancy in 32-year-old

woman

32-year-old woman with intraabdominal pregnancy

Right cornual pregnancy

Cervical Incompetence

Common cause of preg. failure in 2nd trimester Painless dilatation of cervix, preterm labor

Sonographic findings Bulging of fetal membranes into widened in-

ternal os & shortening of the cervical canal Cx length: shortening (>3cm normally, but temporal change)

provocative measure: helpful tool

Endovaginal sonography: more accurate

34-year-old woman with second trimester cervical incompetence

Retroplacental Hematoma & Abruptio Placentae

Bleeding along basal plate of placenta due to primary abruptio placentae or ruptured spiral arteries

Clincal sx Placental abruption with painful vaginal bleeding Consumptive coagulopathy Fetal distress

Sonographic findings: Crescentic low echoic lesion Isoechoic to placenta : mimic thickened placenta low sensitivity

Placental abruption and fetal demise in 28-year-old woman

32-year-old woman in second trimester with placental abruption

Uterine Dehiscence and Rupture

M/C cause of uterine dehiscence: old c/sec scar

Type of rupture Limited to dehiscence of scar w/ intact serosa

– Minimal vaginal bleeding or intraperitoneal hemorrhage

Full-thickness uterine rupture– Massive hemoperitoneum : high fetal & maternal mortality

Sonographic signs of uterine rupture Protruding portion of amniotic sac Endometrial or myometrial defect Extrauterine hematoma & hemoperitoneum

36-year-old woman with uterine rupture af-ter prolonged induction of vaginal delivery

28-year-old woman with surgically proven intraabdominal pregnancy re-

sultingfrom uterine dehiscence

Puerperal Gonadal Vein ThrombosisUncommon, fatal, postpartum complicationPathogenesis Retrograde propagation of thrombosed myometrial

veins draining infected placenta

Sonographic diagnosis Dilated, noncompressible ovarian v. into IVC

Retained Products of ConceptionSx: secondary postpartum hemorrhage or infec-tionSonographic findings Endometrial expansion of heterog. echoic material Focal areas of hyperechogenicity :Retained placental calcifications

32-year-old woman, 4 days postpar-tum Right ovarian vein throm-

bophlebitis

28-year-old woman with retained products of conception

Early pregnancyG-sac

TV US(useful): 31 days or 4+3 weeks of GA(2–3mm)TA US: 5+3 weeks of GAUS finding At uterine fundus & eccentrically placed Intradecidual sign

– Before visualization of yolk sac or embryo– Two concentric rings

Circular transonic area surrounded by thick bright ring: double sac sign

– Thick, bright ring: invading chorionic villi & decidual reaction

Normal intrauterine preg-nancy at 4 weeks’ gestation

Echogenic appearance and thickness of wall of sac

Early pregnancy

Embryo(fetal pole)Conceptus before 10 weeks GATV US: 37 days GAUS finding Bright linear echo, adjacent to yolk sac Close to connecting stalk

Decidual reaction

Early preg-nancy

Yolk sacTV US: About 35 days: first identified After 12 weeks: Identification is difficult

Membranous sac attached to embryo providing early nourishment

Early preg-nancy

AmnionMembrane building amniotic sac that sur-rounds and protects embryoTV US: 6 weeks GA

ChorionMembranes btwn developing fetus & motherduring pregnancy Extraembryonic mesoderm

2 layers of trophoblast Surround embryo &

other membranes

Early preg-nancy

Missed abortionRetention of G-sac in uterus after embry-onic or early fetal deathDx on US Cardiac activity(-) in fetal pole of CRL>6mm

Yolk sac or embryo(-) in G-sac of diameter> 20 mm

– Blighted ovum

BiometryCRL

Most acurate dating of early pregnancy

Long axis of fetusTop of head(crown) to end of trunk (rump)

BPD2nd trimesterBoth thalami & cavum septum pellucidum level

FLAfter 14 weeks GAOssified diaphysis and metaphysis

Biometry

ACSingle vertebra, umbilical vein (UV), stomachwidest part of abdominal circumferencesection

Nuchal translucencyAt CRL(33-88mm) Max. thickness of subcutaneus translucent

area btwn skin & soft tissues overlying

post. aspect of cervical spine on sagital plane

A thickness > 3 mm 90% trisomy 18 & 13 80% trisomy 21 5% normal

Gynecologic Emergencies

Pelvic Inflammatory DiseaseM/C cause of acute pelvic pain Acute complications of PID

– TOA, pyosalpinx & peritonitis

Sonographic finding Early stages or or uncomplicated: normal Severe or advanced

– Usually bilateral– Endometrial thickening +/- endometrial fluid,

gas– Ovarian enlargement w/ indistinct borders– Uterine enlargement w/ indistinct contours– Free intraperitoneal fluid

24-year-old woman with pelvic in-flammatory disease and tuboovarian

complex

15-year-old girl with pelvic pain, fever, and bilateral tuboovarian ab-scesses.

Tuboovarian TorsionComplete or partial torsion of ov. vascular pedi-cle Initially compromises lymphatics & vein

drainage eventual loss of arterial perfusion

Sonographic finding Enlarged ovary, mimic solid hypoechoic or hy-

perechoic adnexal mass Specific sign: multiple cortical follicles in ovary Free intraperitoneal fluid in pelvis Intraovarian artery flow : not exclude torsion Preservation of central venous flow : viable

ovary

30-year-old pregnant woman with surgically proven ovarian torsion

22-year-old woman with ovarian tor-sion

Hemorrhagic Ovarian Cysts

From corpus luteal or follicular origin

Sonographic finding Heterogeneous hypoechoic mass w/ int. echo Thin and thick septations Fluid–debris level Echogenic retracting clot Irregular nodular wall Ac. intracystic hemorrhage: isoechoic to ov.

stroma - mimic an enlarged ovary

34-year-old woman with acute pelvic pain caused by hemorrhagic ovarian cyst.

26-year-old woman with ruptured hemor-rhagic ovarian cyst and hemoperitoneum

Pathology of uterus and ovary

Pathology of uterus

Uterine myomaCommonest gynaecological tumor50% over 40 years Majority of cases of uterine enlarg.

US finding Fibrous tissue : dense concentric rings Well circumscribed hypoechoic, Increased echo within mass Irregular uterine outline: subserosal or multi-

ple Punctate or circumferential calcification(+/-)

Uterine myomaSubserisal myoma vs. ovary fibroma Bridging vascular sign : Uterine origin

AdenomyosisEctopic endometrial glands & stroma in my-ometrium

US finding Ill-defined low or heterogeneous echoic le-

sion in myometrium Diffusely heterogeneous and enlarged uterus : severe form of adenomyosis Small cystic areas, few mm in myometrium

– represent menstrual products

Endometrial polypCommon (10% of women)Often associated with endometrial hyper-plasiaUS finding Discrete mass in endometrium w/ vascular

stalk Sonohysterogram: useful

Pathology of ovaryPolycystic ovaries

Ovary that contains 10 or more cysts measuring 2–8 mm w/ increase in stromaClinical: LH or testosterone Hirsutism, male-pattern baldness, obe-

sity, amenorrhea, acne, oligomenorrhea

Physiologic ovary cystFollicular cyst Result of mature follicle failing to ovulate Thin walled, unilocular cyst w/ hypoechoic

fluid

Corpus Luteal Cysts Rupture of mature follicle, series of

changes during luteal phase Beginng: hypoechoic w/ irregular inner

wall +/- some internal echo

Typical sonographic features suggest-ing malignant ovarian mass

Size —larger than benign lesions

Complexity of the mass a) Cyst wall : thickened (greater than 3 mm) irregular contours papillary projections into cyst b) Intra-cystic septation : thickening , irregular-

ity c) Solid elements: irregular mass from cyst

wall d) Mixed echogenicity cyst fluid

Ascites: peritoneal metastases