gravidez ectópica - radiographics

1. Women’sImaging|RADIOGRAPHICSFUNDAMENTALS
2236
Ectopic Pregnancy: A Trainee’s
Guide to Making the Right Call1
Stephanie N. Histed, MD
Monica Deshmukh, MD
Rinat Masamed, MD
Cecilia M. Jude, MD
Shaden Mohammad, MD
Maitraya K. Patel, MD
Abbreviation: IUP = intrauterine pregnancy
RadioGraphics 2016; 36:2236–2237
Published online 10.1148/rg.2016160080
Content Codes:
1
From the Department of Radiologic Sciences,
University of California, Los Angeles Medical
Center, 757 Westwood Plaza, Los Angeles, CA
90095 (S.N.H., R.M., M.K.P.); and Department
of Radiology, OliveView–UCLA Medical Center,
Sylmar, Calif (M.D., C.M.J., S.M., M.K.P.). Pre-
sented as an education exhibit at the 2015 RSNA
Annual Meeting. Received March 30, 2016; revi-
sion requested June 16 and received September
7; accepted September 16.The author C.M.J. has
provided disclosures (see end of article); all other
authors have disclosed no relevant relationships.
Address correspondence to S.N.H. (e-mail:
shisted@mednet.ucla.edu).
©
RSNA, 2016
The full digital presentation is available online.
Ectopic pregnancy, an embryo implanted outside the normal intra-
uterine location, is the leading cause of first-trimester maternal mor-
tality and hemorrhage.The reported prevalence is 2% of all pregnan-
cies in the United States, which increases to 18% in patients with
first-trimester bleeding. Risk factors include tubal or uterine surgery,
pelvic inflammatory disease, current intrauterine device, endome-
triosis, and in vitro fertilization. Understanding the early normal
pregnancy sequence is important to accurately interpret pelvic ultra-
sonographic (US) images and to prevent a false-positive diagnosis of
ectopic pregnancy in a viable intrauterine pregnancy (IUP).
In a normal IUP, the released oocyte enters the fallopian tube
to eventually implant in the endometrial lining. A gestational sac
appears on US images around a gestational age of 5 weeks, or 3
weeks after fertilization. Serum human chorionic gonadotropin levels
generally follow a predictable pattern in most normal pregnancies,
doubling approximately every 48 hours, but this can also be seen in
up to 21% of ectopic pregnancies.
A yolk sac, seen at approximately 5.5 weeks of gestational age,
confirms the pregnancy and location. Other US findings of normal
early pregnancy include the intradecidual sac sign, an eccentrically
located cyst in the echogenic decidua, and the double decidual sac
sign, two layers of decidua (decidua parietalis and decidua capsu-
laris) surrounding the gestational sac.These signs are absent in at
least 35% of gestational sacs and have poor interobserver agreement.
In 2013, the Society of Radiologists in Ultrasound increased
stringency for diagnosis of early pregnancy nonviability, to reduce
false-positive diagnoses of ectopic pregnancy. According to updated
guidelines, any round or oval intrauterine cystic structure on trans-
vaginal US images in a woman with a positive pregnancy test result
is highly likely to represent an IUP.
An ectopic pregnancy develops from an interruption along any
part of the oocyte’s pathway from the ovary to the endometrial cav-
ity. Ectopic locations include the fallopian tube, abdomen, ovary,
uterine interstitium, prior surgical scar, and cervix.
Ninety-five percent of ectopic pregnancies occur within the fal-
lopian tubes (Fig 1). US findings include an extraovarian adnexal
mass in a woman with a positive pregnancy test result and an empty
Teaching Points
■■ Transvaginal US, with findings interpreted in conjunction with serum human chorionic
gonadotropin values, is the key test to diagnose ectopic pregnancy.
■■ Normal physiology, ectopic pregnancy, and the expected radiologic findings are impor-
tant for the radiology trainee to understand.
■■ Accurate diagnosis as early as possible is essential to help initiate treatment, which may
include local or systemic medications or surgery.
This copy is for personal use only. To order printed copies, contact reprints@rsna.org

2. RG • Volume 36 Number 7 Histed et al 2237
Figure 2. Heterotopic pregnancy. Longitudinal trans-
vaginal gray-scale US image demonstrates two em-
bryonic poles (arrows), with one intrauterine embryo
within the uterine fundus (left arrow), and the second
extrauterine embryo within the cervix (right arrow).
Both embryos had positive fetal cardiac activity.
Figure 1. Tubal ectopic pregnancy. Transverse transvaginal gray-scale (a) and transvaginal Doppler (b) US images
demonstrate an extrauterine pregnancy in the left adnexa with a yolk sac, an embryonic pole, and the ring-of-fire sign.
The ampulla accounts for more than 70% of all tubal ectopic pregnancies.
Treatment selection is dependent on clinical acuity,
desired future fertility, and medical comorbidities.
This online presentation reviews ectopic preg-
nancy in a case-based, multiple-choice question
format. After viewing the presentation, radiolo-
gists and radiology trainees should be able to
identify the expected US findings in a normal
IUP, recognize the variety of locations where an
ectopic pregnancy may be found, and discuss ap-
propriate treatment options.
Disclosures of Conflicts of Interest.—C.M.J. Activities related to
the present article: disclosed no relevant relationships. Activities
not related to the present article: disclosed no relevant relation-
ships. Other activities: author for UpToDate.
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uterus.The less common ectopic locations com-
pose up to 5% of ectopic pregnancies but are
diagnostically more challenging. A cervical ecto-
pic pregnancy can be mistaken for an abortion
in progress. Interstitial and cesarean section scar
ectopic pregnancies may be mistaken for normal
IUPs; due to inadequate surrounding myome-
trium and proximity to vascular structures, these
are at risk for devastating hemorrhage or uterine
rupture. Heterotopic pregnancy, a normal IUP
coexisting with an ectopic pregnancy, is uniquely
challenging as these patients are frequently un-
dergoing assisted reproductive techniques where
preservation of the viable pregnancy is para-
mount (Fig 2).
Treatment options include systemic metho-
trexate, local injection of potassium chloride or
methotrexate into the ectopic pregnancy, surgery, or
expectant management in limited clinical scenarios.