Ectopic Pregnancy Imaging
No Results
No Results
processing….
Ectopic pregnancy continues to be the leading cause of first-trimester maternal death. Although diagnosis and management have improved, the incidence of this disease has continued to climb since the US Centers for Disease Control and Prevention (CDC) started collecting data in 1970. [1, 2] This increase is likely due to a continued rise in the prevalence of predisposing risk factors. Ectopic pregnancy has additional significance in that the associated mortality with this condition usually affects an otherwise healthy segment of the population.
To diagnose an ectopic pregnancy, beta-HCG tests are required. A negative beta-HCG result effectively excludes the diagnosis of an ectopic or intrauterine pregnancy. In unstable patients, surgical evaluation and/or laparoscopy should be performed with or without culdocentesis. In patients with a stable clinical condition, transabdominal (TA) and endovaginal (EV) ultrasonography are performed. [3] The demonstration of an intrauterine gestational sac effectively excludes the diagnosis of an ectopic pregnancy. A search for a possible ectopic pregnancy as part of a heterotopic pregnancy should be attempted.
Medical management is often associated with follow-up imaging. [4, 5] Follow-up ultrasonography, along with follow-up beta-HCG levels, can be helpful if the diagnosis is unclear. A normal intrauterine pregnancy should demonstrate a 48-hour beta-HCG doubling time. [6] Magnetic resonance imaging (MRI) has been used as a problem-solving tool in patients in stable condition and with special circumstances. [3, 7, 8, 9, 10, 11]
Active research continues in an attempt to elucidate an ectopic-specific serum marker. Multiple markers show some diagnostic benefit in attempting to discriminate an ectopic pregnancy from a normal intrauterine gestation; however, their use is still widely in the investigative stage. Some of the many markers investigated include progesterone, cancer antigen-125 (CA-125), pregnancy-associated plasma protein A (PAPP-A), and activin A. [12, 13]
TA and EV ultrasonography are recommended in all studies. In a patient in stable condition, a full bladder should be present as a proper TA ultrasonography window. In unstable patients in whom an expeditious diagnosis is needed, the time delay for the bladder to fill may be undesirable. TA and/or EV ultrasonography may be performed in these patients with an empty bladder.
Both TA and EV examinations should still be performed with the acknowledgment of the limited, yet important, aspects of the TA portion of the examination. TA examination enables better evaluation of the superior uterus and superiorly positioned adnexa. It may aid detection of free peritoneal fluid and/or hemorrhage beyond the cul-de-sac. [14]
Transvaginal examination provides a detailed evaluation of the endometrial cavity and ovaries, but the high-frequency transducer that allows improved near-field resolution compared with TA examinations suffers from limited sound penetration (far-field imaging).
MRI examination is time consuming and costly. Computed tomography (CT) scan findings are nonspecific in ectopic pregnancies and pose a hazard of ionizing radiation, which may be harmful to normal pregnancies.
For patient education information, see the Pregnancy and Reproduction Center, Women’s Health Center, and Sexually Transmitted Diseases Center, as well as Ectopic Pregnancy.
No clinically useful plain radiographic findings of ectopic pregnancy have been identified. The associated ionizing radiation poses a hazard if a normal intrauterine pregnancy is present.
CT scan findings are nonspecific for ectopic pregnancy. The associated ionizing radiation poses a hazard if a normal intrauterine pregnancy is present. CT scanning is typically not an appropriate imaging modality to be used for the analysis of ectopic pregnancy. [10]
MRI findings that can suggest an ectopic pregnancy include the presence of (1) a tubal gestational sac; (2) a tubal hematoma, which is a hematoma suggested by the ring sign (peripheral hyperintensity) on T1-weighted images; (3) tubal wall enhancement; and (4) an adnexal mass with hemorrhagic fluid in the peritoneum. Blood is suggested by the presence of high-signal-intensity fluid on T1-weighted images. [15, 16, 17, 18, 19, 20, 9, 10]
The MRI characteristics of an ectopic pregnancy and its rupture are seen in the T2-weighted images below.
MRI should be used only as a problem-solving tool in the patient who is in stable condition. This imaging modality is accurate in the characterization of tissue and in the detection and age determination of blood products.
On MRI, high T1 signal intensity fluid in a fallopian tube is abnormal. [21] With a positive beta-HCG result, this finding suggests an ectopic pregnancy. Subacute blood products associated with an adnexal mass are also indicative of an ectopic pregnancy. MRI can additionally delineate confounding adnexal findings seen on ultrasonography, such as follicular or corpus luteum cysts.
Early intrauterine pregnancy or a missed abortion may be associated with normal MRI findings and thus falsely suggest an ectopic pregnancy. However, this scenario is not likely because of the high sensitivity of MRI in detecting associated fluid and blood products with true ectopic pregnancies.
The appearance of an adnexal mass is not necessarily specific on MRI. Corpus luteum cysts and other masses may be confused with ruptured or unruptured ectopic pregnancy. False-positive results can be caused by abnormal tubal fluid or enhancement, as seen with pelvic inflammatory disease and simple hydrosalpinx; however, these findings should be correlated with a positive beta-HCG.
Findings of an extrauterine ectopic pregnancy include the following [22, 23, 24, 25, 11] :
Live, extrauterine embryo
Absence of an intrauterine gestational sac
Free fluid (particularly hemorrhagic) in the pelvis or peritoneum
Adnexal mass [26]
Hematosalpinx
Adnexal ring sign and a “ring-of-fire” sign on color Doppler ultrasonographic images [27]
Absence of low-resistance endometrial arterial flow, which is an endometrial color Doppler ultrasonographic finding that is highly suggestive of intrauterine pregnancy
See the images below.
Findings of an interstitial ectopic pregnancy include the following:
Eccentric location of the gestational sac
Thinning or the absence of myometrium surrounding the sac
Interstitial-line sign, or a hyperechoic line extending from the central endometrial cavity to the peripheral interstitial pregnancy, which is created by the interstitial portion of the endometrium or fallopian tube
When correlating beta-HCG levels with ultrasonographic findings, it is important to take into account the standard of measurement. Both the 2IS and IRP systems are used to report beta-HCG values. An IRP value is approximately twice the corresponding 2IS value.
With a positive beta-HCG level greater than 1000 IU/mL (2IS standard) or 2000 IU/mL (IRP standard), a gestational sac should be identifiable within the uterus on transvaginal sonograms. [26, 28, 29] For TA scanning, a higher threshold of 1800 IU/mL (2IS standard) or 3600 IU/mL (IRP standard) should be used. An intrauterine pregnancy can be definitely diagnosed by the double-decidual-sac sign or by the demonstration of an embryo with a positive heartbeat. Cardiac activity should be identifiable in a fetus when it is found within a gestational sac during transvaginal ultrasonography with a mean diameter of 16 mm or a crown-rump length of 5 mm. [30]
If an intrauterine gestational sac is not found, an ectopic pregnancy must be considered. If the patient’s beta-HCG concentration is below the threshold level and if the only finding is the lack of an intrauterine gestational sac, serial follow-up examinations and beta-HCG determinations are required. A normal intrauterine pregnancy should demonstrate a beta-HCG doubling time of 48 hours. [6] Below the threshold level, ultrasonography does not aid in differentiating an early intrauterine pregnancy, a missed abortion, and an ectopic pregnancy.
The double decidual sac found with an early intrauterine pregnancy can be difficult to distinguish from the pseudogestational sac, which is seen in 20-50% of ectopic pregnancies. The double decidual sac is 2 concentric hyperechoic rings created by hypoechoic fluid between the decidua parietalis and the decidua capsularis. This sign is in distinct contrast to a single hyperechoic layer found with a pseudogestational sac (see the images below). The lack of a yolk sac, the more-irregular contours, and the more-central location within the endometrial cavity also help in delineating a pseudogestational sac from an early intrauterine pregnancy.
Further support of a pseudogestational sac can be demonstrated by the absence of low-resistance endometrial arterial flow on color Doppler ultrasonographic evaluation. The low pulsatility and the low-resistance flow are highly suggestive of an intrauterine pregnancy. This low-resistance flow should have a resistive index less than 0.6 or a peak systolic frequency of 0.8 kHz or greater. [2, 31]
The combination of the Doppler and ultrasonographic findings should be used to differentiate the early intrauterine pregnancy from a pseudogestational sac. However, Doppler ultrasonographic evaluation has not been shown to be of value when attempting to delineate an adnexal ectopic pregnancy from a corpus luteum cyst, particularly as corpus luteum cysts can demonstrate marked peripheral color Doppler ultrasonographic signal, simulating the ring-of-fire’ sign (see the image below). The intraovarian location is the main factor in distinguishing a corpus luteum cyst.
The only specific sign of an ectopic pregnancy is the presence of a live extrauterine gestation. Free fluid is nonspecific and may present as anechoic or echogenic and in varying amounts. Simple free fluid and an empty uterus have a sensitivity of only 63% and a specificity of only 69%. [30] However, hyperechoic fluid and/or large amounts of free fluid are more suggestive of an ectopic pregnancy. [6, 32]
The remaining signs seen in ectopic pregnancy lack sufficient sensitivity and specificity to be used as sole indicators. Because of the variety of ultrasonographic findings, these must be correlated with the clinical presentation and further evaluated to differentiate a possible ectopic pregnancy from an alternate diagnosis.
There are no clear guidelines regarding if or when follow-up sonograms should be obtained. Follow-up examinations should be performed on an individual case basis, in coordination with patient’s the clinical scenario and the beta-HCG levels.
False-positive ultrasonographic findings may be due to a missed abortion or an early normal intrauterine pregnancy (< 4.5 wk), without or with secondary findings of an adnexal mass. The latter scenario may include an intrauterine pregnancy with a hemorrhagic corpus luteum cyst or an intrauterine pregnancy with an adnexal mass, as can be found with concurrent appendicitis.
False-negative findings may be due to an intrauterine decidual reaction pseudosac that simulates an early intrauterine pregnancy. Approximately 8% of proven ectopic pregnancies are ultrasonographically normal on retrospective evaluation. [2] A concomitant intrauterine pregnancy and ectopic pregnancy (particularly in infertility patients) are other causes of false-negative findings for ectopic pregnancy.
As a note of caution, the limited far field of transvaginal ultrasonography can occasionally miss an ectopic pregnancy that is in a high position. Analysis of the patient’s symptoms and placing a transducer on the area of maximal pain may aid the examination. The TA probe can help with this and provide a more global view of the pelvis and its contents.
Centers for Disease Control and Prevention. Ectopic pregnancy–United States, 1990-1992. MMWR Morb Mortal Wkly Rep. 1995 Jan 27. 44(3):46-8. [Medline]. [Full Text].
Rumack CM. Ectopic pregnancy. Rumack CM, Wilson SR, Charboneau JW eds. Diagnostic Ultrasound. 2nd ed. St. Louis, Mo: CV Mosby; 1998. 998-1004.
Sun SY, Araujo Júnior E, Elito Júnior J, Rolo LC, Campanharo FF, Sarmento SG, et al. Diagnosis of heterotopic pregnancy using ultrasound and magnetic resonance imaging in the first trimester of pregnancy: a case report. Case Rep Radiol. 2012. 2012:317592. [Medline]. [Full Text].
American College of Emergency Physicians. ACEP emergency ultrasound guidelines-2001. Ann Emerg Med. 2001 Oct. 38(4):470-81. [Medline].
American College of Obstetricians and Gynecologists. ACOG practice bulletin no. 3. Medical management of tubal pregnancy. December 1998. Clinical management guidelines for obstetrician-gynecologists. Int J Gynaecol Obstet. 1999 Apr. 65(1):97-103. [Medline].
Botash RJ, Spirt BA. Color Doppler imaging aids in the prenatal diagnosis of congenital diaphragmatic hernia. J Ultrasound Med. 1993 Jun. 12(6):359-61. [Medline].
Parker RA 3rd, Yano M, Tai AW, Friedman M, Narra VR, Menias CO. MR imaging findings of ectopic pregnancy: a pictorial review. Radiographics. 2012 Sep-Oct. 32(5):1445-60; discussion 1460-2. [Medline].
Wu R, Klein MA, Mahboob S, Gupta M, Katz DS. Magnetic resonance imaging as an adjunct to ultrasound in evaluating cesarean scar ectopic pregnancy. J Clin Imaging Sci. 2013. 3:16. [Medline]. [Full Text].
Si MJ, Gui S, Fan Q, Han HX, Zhao QQ, Li ZX, et al. Role of MRI in the early diagnosis of tubal ectopic pregnancy. Eur Radiol. 2015 Sep 15. [Medline].
Kao LY, Scheinfeld MH, Chernyak V, Rozenblit AM, Oh S, Dym RJ. Beyond ultrasound: CT and MRI of ectopic pregnancy. AJR Am J Roentgenol. 2014 Apr. 202 (4):904-11. [Medline].
Frates MC, Doubilet PM, Peters HE, Benson CB. Adnexal sonographic findings in ectopic pregnancy and their correlation with tubal rupture and human chorionic gonadotropin levels. J Ultrasound Med. 2014 Apr. 33 (4):697-703. [Medline].
Katsikis I, Rousso D, Farmakiotis D, et al. Receiver operator characteristics and diagnostic value of progesterone and CA-125 in the prediction of ectopic and abortive intrauterine gestations. Eur J Obstet Gynecol Reprod Biol. 2006 Apr 1. 125(2):226-32. [Medline].
Florio P, Severi FM, Bocchi C, et al. Single serum activin a testing to predict ectopic pregnancy. J Clin Endocrinol Metab. 2007 May. 92(5):1748-53. [Medline]. [Full Text].
Hertzberg BS, Kliewer MA, Bowie JD. Sonographic evaluation for ectopic pregnancy: transabdominal scanning of patients with nondistended urinary bladders as a complement to transvaginal sonography. AJR Am J Roentgenol. 1999 Sep. 173(3):773-5. [Medline]. [Full Text].
Jung SE, Byun JY, Lee JM, et al. MR imaging of maternal diseases in pregnancy. AJR Am J Roentgenol. 2001 Dec. 177(6):1293-300. [Medline]. [Full Text].
Kataoka ML, Togashi K, Kobayashi H, et al. Evaluation of ectopic pregnancy by magnetic resonance imaging. Hum Reprod. 1999 Oct. 14(10):2644-50. [Medline]. [Full Text].
Nagayama M, Watanabe Y, Okumura A, et al. Fast MR imaging in obstetrics. Radiographics. 2002 May-Jun. 22(3):563-80; discussion 580-2. [Medline]. [Full Text].
Nishino M, Hayakawa K, Kawamata K, Iwasaku K, Takasu K. MRI of early unruptured ectopic pregnancy: detection of gestational sac. J Comput Assist Tomogr. 2002 Jan-Feb. 26(1):134-7. [Medline].
Outwater EK, Talerman A, Dunton C. Normal adnexa uteri specimens: anatomic basis of MR imaging features. Radiology. 1996 Dec. 201(3):751-5. [Medline]. [Full Text].
Yoden E, Imajo Y, Yamauchi H, Kohno I. Ectopic pregnancy showing interesting findings on MR imaging. AJR Am J Roentgenol. 2001 Mar. 176(3):818-9. [Medline]. [Full Text].
Outwater EK, Siegelman ES, Chiowanich P, et al. Dilated fallopian tubes: MR imaging characteristics. Radiology. 1998 Aug. 208(2):463-9. [Medline]. [Full Text].
Albayram F, Hamper UM. First-trimester obstetric emergencies: spectrum of sonographic findings. J Clin Ultrasound. 2002 Mar-Apr. 30(3):161-77. [Medline].
Atri M, Chow CM, Kintzen G, et al. Expectant treatment of ectopic pregnancies: clinical and sonographic predictors. AJR Am J Roentgenol. 2001 Jan. 176(1):123-7. [Medline]. [Full Text].
Filly RA. Ectopic pregnancy. Callen PW, ed. Ultrasonography in Obstetrics and Gynecology. 3rd ed. Philadelphia, Pa: WB Saunders Co; 1988. 447-52.
Zinn HL, Cohen HL, Zinn DL. Ultrasonographic diagnosis of ectopic pregnancy: importance of transabdominal imaging. J Ultrasound Med. 1997 Sep. 16(9):603-7. [Medline].
Condous GS. Ultrasound diagnosis of ectopic pregnancy. Semin Reprod Med. 2007 Mar. 25(2):85-91. [Medline].
Hertzberg BS, Kliewer MA, Bowie JD. Adnexal ring sign and hemoperitoneum caused by hemorrhagic ovarian cyst: pitfall in the sonographic diagnosis of ectopic pregnancy. AJR Am J Roentgenol. 1999 Nov. 173(5):1301-2. [Medline]. [Full Text].
Gurel S, Sarikaya B, Gurel K, Akata D. Role of sonography in the diagnosis of ectopic pregnancy. J Clin Ultrasound. 2007 Nov-Dec. 35(9):509-17. [Medline].
Sawyer E, Jurkovic D. Ultrasonography in the diagnosis and management of abnormal early pregnancy. Clin Obstet Gynecol. 2007 Mar. 50(1):31-54. [Medline].
Frates MC, Laing FC. Sonographic evaluation of ectopic pregnancy: an update. AJR Am J Roentgenol. 1995 Aug. 165(2):251-9. [Medline]. [Full Text].
Wherry KL, Dubinsky TJ, Waitches GM, Richardson ML, Reed S. Low-resistance endometrial arterial flow in the exclusion of ectopic pregnancy revisited. J Ultrasound Med. 2001 Apr. 20(4):335-42. [Medline].
Dart R, McLean SA, Dart L. Isolated fluid in the cul-de-sac: how well does it predict ectopic pregnancy?. Am J Emerg Med. 2002 Jan. 20(1):1-4. [Medline].
Douglas Bourgon, MD Diagnostic Radiologist, Image Guided Therapeutics
Douglas Bourgon, MD is a member of the following medical societies: American College of Radiology, American Medical Association, American Roentgen Ray Society, Radiological Society of North America
Disclosure: Nothing to disclose.
Gregory Balmforth, MD Staff Physician, Department of Diagnostic Radiology, University Medical Center, University of Arizona
Disclosure: Nothing to disclose.
Eric K Outwater, MD Professor, Department of Radiology, University of South Florida
Eric K Outwater, MD is a member of the following medical societies: American College of Radiology, Phi Beta Kappa, Radiological Society of North America
Disclosure: Nothing to disclose.
Bernard D Coombs, MB, ChB, PhD Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand
Disclosure: Nothing to disclose.
Karen L Reuter, MD, FACR Professor, Department of Radiology, Lahey Clinic Medical Center
Karen L Reuter, MD, FACR is a member of the following medical societies: American Association for Women Radiologists, American College of Radiology, American Institute of Ultrasound in Medicine, American Roentgen Ray Society, Radiological Society of North America
Disclosure: Nothing to disclose.
Eugene C Lin, MD Attending Radiologist, Teaching Coordinator for Cardiac Imaging, Radiology Residency Program, Virginia Mason Medical Center; Clinical Assistant Professor of Radiology, University of Washington School of Medicine
Eugene C Lin, MD is a member of the following medical societies: American College of Nuclear Medicine, American College of Radiology, Radiological Society of North America, Society of Nuclear Medicine and Molecular Imaging
Disclosure: Nothing to disclose.
Harris L Cohen, MD, FACR Chairman, Department of Radiology, Professor of Radiology, Pediatrics, and Obstetrics and Gynecology, University of Tennessee Health Science Center College of Medicine; Radiologist-in-Chief, LeBonheur Children’s Hospital; Emeritus Professor of Radiology, The School of Medicine at Stony Brook University
Harris L Cohen, MD, FACR is a member of the following medical societies: American College of Radiology, American Institute of Ultrasound in Medicine, Radiological Society of North America, Society for Pediatric Radiology, Association of Program Directors in Radiology, Society of Radiologists in Ultrasound
Disclosure: Nothing to disclose.
Ectopic Pregnancy Imaging
Research & References of Ectopic Pregnancy Imaging|A&C Accounting And Tax Services
Source
0 Comments