Complicated first-trimester pregnancies: evaluation with endovaginal US versus transabdominal technique

Endovaginal ultrasound (US) was performed in 38 pregnant women at 5-12 menstrual weeks, when the initial transabdominal sonograms had been considered inconclusive or equivocal. Clinical follow-up disclosed 32 intrauterine pregnancies (12 living, 18 spontaneous incomplete abortions, and two embryonic demises) and six ectopic pregnancies. In the 32 intrauterine pregnancies (normal and abnormal), the correct diagnosis was made in all cases with endovaginal US. The endovaginal images demonstrated the intrauterine embryo, its heart motion, and the yolk sac more clearly and more often when these structures were not apparent on the transabdominal scans. Abnormal gestational sacs were better resolved. In the six cases of ectopic pregnancy, while an extrauterine ectopic sac was visualized in only three, absence of an intrauterine gestational sac was confirmed in all cases with endovaginal scanning. No endovaginal study yielded less information than its transabdominal counterpart. Endovaginal sonography is likely to be diagnostic when transabdominal images fail to yield a definitive diagnosis in early pregnancies.     

Diagnosis of ectopic pregnancy: endovaginal vs transabdominal sonography

During a 25-month period, 193 women with the clinical diagnosis of suspected ectopic pregnancy had transabdominal and endovaginal sonograms. Most had quantitative determinations of serum human chorionic gonadotropin (HCG). Endovaginal sonography was diagnostic of ectopic pregnancy in 23 (38%) of the 60 patients with surgically proved ectopic pregnancies: transabdominal sonography was diagnostic in 13 patients (22%). All 83 intrauterine pregnancies were identified with endovaginal sonography, compared with 34 identified with transabdominal sonography. Endovaginal sonography was somewhat more helpful in the diagnosis of missed abortion and blighted ovum. Eighty endovaginal sonograms were classified as indeterminate as compared with 141 transabdominal studies. This indeterminate group included patients with complete abortions, ectopic pregnancies without sonographic evidence of an extrauterine gestation, incomplete abortions, and patients with subsequent negative serum levels. As in prior reports, endovaginal sonography was superior to transabdominal sonography in the evaluation of suspected ectopic pregnancies. Overall, endovaginal sonography was diagnostic in 113 patients, whereas transabdominal sonography was diagnostic in 52 patients. The finding of an extrauterine fetal pole or embryo was diagnostic for an ectopic pregnancy. Pelvic fluid, the appearance of the endometrium, and a single positive serum HCG determination were not helpful in making the diagnosis of ectopic pregnancy.     

Comparison of transvaginal and transabdominal sonography in the detection of early pregnancy and its complications

Ninety women with a positive pregnancy test and signs and symptoms of threatened abortion or ectopic pregnancy had endovaginal and abdominal sonography in order to compare the value of the two techniques for the detection of gestational abnormalities. Either a normal delivery occurred or surgical and/or pathologic confirmation of the diagnosis was available in all cases. Fifty-five women had normal intrauterine pregnancies, 22 had ectopic pregnancies, seven had blighted ova, and six had missed abortions. All 55 normal intrauterine pregnancies were detected by endovaginal sonography, while only 11 (20%) were diagnosed by transabdominal sonography. The yolk sac, fetal pole, and fetal heart motion were seen as early as 34 days from the last menstrual period with endovaginal sonography, compared with 42 days with transabdominal sonography. Fetal heart motion was detected with endovaginal sonography in fetal poles with a crown-rump length of 3 mm or greater, whereas the fetal pole had to be at least 6 mm before fetal heart motion could be detected with the transabdominal technique. In the 22 ectopic pregnancies, a specific diagnosis of an extrauterine sac containing a fetal pole with heart motion or yolk sac was possible in three cases with the endovaginal technique, but it was not possible in any case with transabdominal sonography. Both techniques showed that each of the seven patients with final diagnosis of blighted ova had a gestational sac that was 1.7 cm or larger without visualization of the fetal pole or yolk sac. All six missed abortions were detected by endovaginal sonography, but only three were diagnosed on transabdominal sonograms. Our findings show that endovaginal sonography is more sensitive than transabdominal sonography in the detection of early pregnancy and its complications.     

Suspected ectopic pregnancy: endovaginal and transvesical US

Until the advent of endovaginal ultrasonography (US), transvesical US was the only US technique availab le for evaluation of patients with suspected ectopic gestation. A study was undertaken to assess the predictive ability of transvesical and endovaginal US and determine whether endovaginal US could be used alone. Fifty-three patients who had a positive pregnancy test finding and who were at risk for ectopic pregnancy were examined with both endovaginal and transvesical US. Twenty-nine were examined retrospectively and 24 were examined prospectively. Standard sonographic criteria were used to differentiate between intrauterine pregnancy and ectopic gestation. The clinical or pathologic diagnosis was ectopic pregnancy in 18 patients (34%), normal intrauterine pregnancy in 19 (36%), and abnormal intrauterine pregnancy in 16 (30%). Endovaginal US increased the sensitivity of detecting a live ectopic pregnancy (from 6% to 17%). Endovaginal US, by allowing early diagnosis of intrauterine pregnancy, significantly increased the diagnostic accuracy for ectopic pregnancy (from 60% to 83%). Endovaginal US provided significant additional information in women referred for sonography with a suspected ectopic gestation. On the basis of these findings it is concluded that endovaginal US can be used alone in the majority of women with suspected ectopic gestation.     

Ectopic pregnancy: evaluation with endovaginal color flow imaging.

Endovaginal sonography and endovaginal color flow imaging were compared in 155 patients with clinical suspicion of ectopic pregnancy. Sixty-five patients (42%) had surgically confirmed ectopic pregnancies. Thirty-six of the pregnancies were diagnosed with endovaginal sonography alone, the criteria being an extrauterine sac or ectopic fetus (sensitivity, 54%). Sixty-two ectopic pregnancies were diagnosed with endovaginal color flow imaging (sensitivity, 95%) when an ectopic fetus or sac was seen or placental flow was identified in an adnexal mass separate from the ovary and uterus. The diagnosis of ectopic pregnancy was excluded with endovaginal sonography (specificity, 98%) and endovaginal color flow imaging (specificity, 98%) by finding an intrauterine gestation, nonvisualization of an adnexal mass, and absence of placental flow. Three false-positive and three false-negative diagnoses were made with endovaginal color flow imaging (positive predictive value, 97%). The addition of color Doppler flow imaging to endovaginal sonography allows increased sensitivity in the detection of ectopic pregnancy.     

Early pregnancy complications: endovaginal sonographic findings correlated with human chorionic gonadotropin levels

Endovaginal sonography results were compared with quantitatively determined human chorionic gonadotropin (hCG) levels in 84 women referred for early pregnancy complications. Of the 27 with normal intrauterine pregnancies, an intrauterine gestational sac was prospectively identified in one of five cases (20%) in which hCG levels were below 500 IU/L (Second International Standard), four of five (80%) with hCG levels of 500-1,000 IU/L, and all 17 with hCG levels above 1,000 IU/L. In comparison, 17 of the 26 women with ectopic pregnancies (65%) had hCG levels greater than 1,000 IU/L, and none of the 26 had an intrauterine gestational sac. Endovaginal sonography demonstrated an adnexal mass and/or a gestational sac-like structure in 16 of the 17 cases (94%) in which hCG levels were above 1,000 IU/L, compared with only three of the nine (33%) with lower hCG levels (P less than .01). These findings indicate that an intrauterine gestational sac should be normally visualized with endovaginal sonography when the hCG level exceeds 1,000 IU/L, and that visualization of an extrauterine gestational sac and/or adnexal mass is significantly more likely in ectopic pregnancies when the hCG level exceeds 1,000 IU/L.     

Ultrasound in the first trimester of pregnancy

High-resolution sonography, including transvesical and endovaginal techniques, has resulted in enhanced visualization of embryonic and extraembryonic structures. With endovaginal sonography, the gestational sac may be seen within the decidua at about 4.5 weeks menstrual age. The yolk sac is the first structure to be seen within the gestational sac, and confirms the presence of a gestational sac rather than a decidual cast. The embryo is identified by endovaginal sonography early in the 6th week, and cardiac activity is routinely identified by a crown-rump length of 3 to 5 mm. On endovaginal sonography, absent cardiac activity in an embryo having a crown-rump length of greater than 3 to 5 mm indicates embryonic death. With endovaginal scanning, a gestational sac of greater than 8 mm without a yolk sac, or greater than 16 mm without an embryo, also indicates a nonviable pregnancy. Routine sonography primarily to assess the menstrual age should be performed in the second trimester, when added clinically relevant information may be obtained. Although it is possible to diagnose some anomalies in the first trimester, most remain second trimester sonographic diagnoses.     

Extrauterine findings of ectopic pregnancy of transvaginal US: importance of echogenic fluid

Transvaginal ultrasound (US) studies of 232 consecutive patients with positive serum pregnancy tests who were considered to be at risk for ectopic pregnancy were prospectively evaluated to determine the significance of various extrauterine findings, including echogenic fluid in the cul-de-sac. All patients were found to have a surgically proved ectopic gestation (group 1, 68 patients [29.3%]), reliable evidence of intrauterine pregnancy at initial transvaginal US (group 2, 83 patients [35.8%]), or no evidence of pregnancy at initial transvaginal US, but subsequent proof of an intrauterine pregnancy (group 3, 81 patients [34.9%]). Adnexal findings were demonstrated in 45 (66%) group 1 patients, including a living extrauterine embryo in 10 (15%), an extrauterine gestational sac in 21 (31%), and an adnexal mass in 14 (21%). Intraperitoneal fluid was detected in 43 (63%) group 1 patients and in 81 (31%) group 3 patients. Echogenic fluid was the only abnormal finding at US in 10 (15%) group 1 patients and added confidence to the diagnosis of ectopic pregnancy in many others. Echogenic fluid correlated with hemoperitoneum at the time of surgery. The presence of echogenic fluid indicates a high risk for ectopic pregnancy in women referred with this clinical indication.     

Early diagnosis of nonviable pregnancy with endovaginal US

The mean diameter of the gestation sac and the presence or absence of a yolk sac or embryo and/or cardiac pulsations on endovaginal ultrasound (US) images were correlated with normal and abnormal outcomes of pregnancy. Sixty-two patients who were less than 10 weeks pregnant (menstrual age) underwent endovaginal US. In 59 patients with gestation sacs greater than or equal to 8 mm, the absence of a yolk sac predicted a nonviable pregnancy with a sensitivity of 67% and a specificity of 100%. In 35 patients with gestation sacs greater than or equal to 16 mm, the absence of an embryo predicted a nonviable pregnancy with a sensitivity of 50% and a specificity of 100%. When the absence of cardiac pulsations was added to the latter group of patients, the sensitivity was 100% and the specificity was 100%. The combination of these criteria (gestation sac size; demonstration of yolk sac, embryo and/or cardiac pulsations) enabled the early (less than 10 weeks menstrual age) diagnosis of a nonviable pregnancy with endovaginal US.     

Transvaginal sonography in the evaluation of normal early pregnancy: correlation with HCG level

Transvaginal sonography (TVS) is the procedure of choice in evaluating the viability of embryos early in pregnancy. However, viability based on TVS can be assessed more accurately when the exact gestational age from the last menstrual period is known or when the findings are correlated with beta human chorionic gonadotropin (HCG) levels. No large series has been reported with correlative data between early pregnancy findings, HCG, and gestational age. We performed 75 transvaginal examinations in 53 patients with proved normal pregnancy in the fifth through seventh weeks of gestation. The presence and size of the gestational sac, presence of a yolk sac, and identification of embryonic heart activity were correlated with the level of HCG. Sac size was correlated with yolk sac and heart activity and the three parameters correlated with gestational age in days. When the level of HCG reached 1000 mIU/ml by using the first International Reference Preparation, a gestational sac was seen sonographically in each patient. When the HCG level reached 7200 mIU/ml, a yolk sac was seen in every patient. Ten of 22 patients with HCG between 1000 and 7200 mIU/ml had a visible yolk sac. Every patient with an HCG level greater than 10,800 mIU/ml had a visible embryo with a heartbeat. A discriminatory level of 32 days was found for the presence of a gestational sac. A yolk sac was first seen in every patient between 36 and 40 days. Every patient with accurate dates greater than 40 days had an embryo with a heartbeat identified. When correlating sac size with structures within the sac, a yolk sac was first seen in a gestational sac between 6 and 9 mm and a heartbeat seen in every patient with a 9-mm or greater gestational sac diameter. These data allow identification of normal intrauterine pregnancy and distinction of normal from ectopic gestation at least 1 week earlier than is possible with transabdominal techniques.     

Endometrial abnormalities: evaluation with transvaginal sonography

The value of transvaginal sonography in detecting gynecologic disease currently is being defined. To evaluate transvaginal depiction of the endometrium, transvaginal sonograms were compared with conventional transabdominal scans in 29 patients whose sonograms revealed endometrial abnormalities. The two techniques were compared for image quality and ability to provide unique diagnostic information. Sonographic findings included fluid collections (16), thickened and/or echogenic endometria (10), endometrial irregularities (two), and echogenic foci (two). Clinical diagnoses included early intrauterine pregnancies (five), pseudogestational sacs of ectopic pregnancy (one), intrauterine contraceptive devices (two), endometrial carcinoma (one), and intrauterine synechiae with amenorrhea (Asherman syndrome) (two). In most cases (77%), diagnostic information was obtainable by either transabdominal or transvaginal sonograms, although in 23% transvaginal scanning provided unique diagnostic information not available with the transabdominal technique. In no case did transabdominal sonography contribute diagnostic information not provided transvaginally. The quality of the transvaginal image was judged to be better than that of the transabdominal image in 63% of cases; image quality was the same in 33% of cases and worse in 3% of cases. The results show that transvaginal sonography is often superior to transabdominal scanning in the evaluation of endometrial abnormalities. Transvaginal sonography may be the preferred technique in these cases.     

Diagnostic efficacy of endovaginal color Doppler flow imaging in an ectopic pregnancy screening program.

The authors compared the diagnostic yield of endovaginal color and pulsed Doppler ultrasound (US) in conjunction with endovaginal sonography with that of endovaginal sonography alone in patients prescreened to be at increased risk for ectopic pregnancy. Pelvic structures were evaluated for overall vascularity and for the presence of characteristic pulsed Doppler US velocity waveforms. The diagnostic sensitivity of the initial endovaginal sonographic examination increased with the addition of color and pulsed Doppler US, from 71% to 87% for ectopic pregnancy, from 24% to 59% for failed intrauterine pregnancy, and from 90% to 99% for viable intrauterine pregnancy. Specificities for endovaginal sonography with color and pulsed Doppler US ranged from 99% to 100%. Use of endovaginal color and pulsed Doppler US increased the percentage of diagnostic initial sonographic examinations from 62% to 82%. The improved diagnostic sensitivity of endovaginal color Doppler US for ectopic pregnancy may ultimately result in earlier treatment, with reduced morbidity and mortality.     

Endovaginal color Doppler sonographic evaluation of ectopic pregnancy in women after in vitro fertilization and embryo transfer

The aim of this study was to evaluate the value of endovaginal color Doppler ultrasonography in the early diagnosis of ectopic pregnancy in women after in vitro fertilization and embryo transfer, and to correlate the sonographic findings with ?-hCG serum levels. Thirty-five patients had proven ectopic pregnancies and 4 other patients had heterotopic pregnancies. The diagnosis was disclosed correctly in all cases by endovaginal color Doppler US by identifying an adnexal mass with placental flow and a nongravid uterus called a “cold uterus”. An intrauterine sac with “double ring sign” was found in all normal intrauterine pregnancies when the hCG levels exceeded 1000 IU/l but in none of the patients with ectopic pregnancy (EP). These findings suggest the efficacy of the discriminatory hCG serum level of 1000 IU/l in the investigation of EP. In conclusion, this study describes the diagnostic importance of transvaginal color Doppler US in correlation with hCG serum levels in the early detection of EP avoiding life-threatening complications and improving patient outcome. Received: 4 May 1998; Revision received: 10 August 1998; Accepted: 10 September 1998     

Transabdominal versus endovaginal pelvic sonography: prospective study

Transabdominal and endovaginal pelvic sonograms were obtained in 108 nonpregnant patients referred for pelvic sonography. The studies were independently obtained by two radiologists and interpreted on the basis of identical clinical information. The sonograms were then compared for anatomic detail and abnormalities. A determination was made about which examination, if either, was superior. Follow-up was performed through a review of the medical records and follow-up studies. Overall, the endovaginal study was judged superior in 65 cases (60.2%), equal in 39 (36.1%), and inferior in four (3.7%). The authors conclude that the endovaginal examination can effectively replace the transabdominal examination as the initial approach for routine pelvic sonography.     

Transvaginal sonographic evaluation of the retrodisplaced uterus

To determine the clinical value of transvaginal sonography in the assessment of retrodisplaced uteri, the authors reviewed, retrospectively, 500 consecutive transvaginal (TV) and transabdominal (TA) sonograms. Of the 494 patients examined, 27 had a retrodisplaced uterus. Transvaginal sonography was superior to TA sonography in 25 patients, providing improved visualization of the endometrial canal, myometrium, adnexa and cul-de-sac. In 7 of these 25 patients, the findings that suggested the diagnosis were only seen on TV scanning. These findings included intrauterine pregnancy (three patients), fluid collection in the cul-de-sac (two patients), fluid collection in the endometrial canal (one patient) and an embedded intrauterine contraceptive device (one patient). The two techniques yielded the same information in two other patients. In no patient was TA sonography more informative than TV sonography. The authors, therefore, conclude that TV sonography is the procedure of choice in assessing a retrodisplaced uterus and that additional examination with TV sonography is advisable whenever a retrodisplaced uterus is suspected.     

Ectopic pregnancy: duplex Doppler evaluation

Of 398 patients in whom there was a clinical suspicion of ectopic pregnancy, 96 (24%) were found to have the condition. Of the 96, 70 underwent duplex Doppler imaging. A viable ectopic fetus was seen in 10 of 70 (14%), and an extrauterine sac without an identifiable fetus was seen in an additional 27, giving a sensitivity for imaging alone of 53%. Fetal heart activity was detected with Doppler in 13 (19%). High-velocity flow, which suggested the presence of an ectopic pregnancy, was detected in 38 of 70 (54%) patients (total preoperative sensitivity, 73%). In the 91 patients who did not have an ectopic pregnancy, duplex Doppler imaging of the intrauterine contents alone allowed an ectopic pregnancy to be excluded in 29 (32%) on the first examination and in a further 21 on the second scan (specificity, 55%). Nine vascular adnexal masses were falsely considered to be ectopic pregnancies (specificity, 90%). The positive predictive values were 47% for imaging alone and 85% for Doppler. The negative predictive values were 60% for imaging alone and 81% for Doppler.     

Analysis of ultrasonographic criteria in the evaluation for ectopic pregnancy.

To assess the usefulness of ultrasound in diagnosing ectopic pregnancy, the ultrasonographic findings, pregnancy test results, and proven diagnoses in 148 patients referred for evaluation for ectopic pregnancy were reviewed. Of these patients, 33 were subsequently proven to have ectopic gestations. The ultrasonograms were coded for uterine size, intrauterine gestation sac, adnexal mass, adnexal ring, cul-de-sac fluid, or normal findings. With a positive pregnancy test, the presence of an intrauterine gestation sac excludes the diagnosis of ectopic pregnancy. Of those patients with positive pregnancy tests and no intrauterine gestation sac, 73% had ectopic pregnancy. All patients with normal ultrasonograms had other diagnoses. With a negative pregnancy test, the intrauterine findings are not helpful, and evaluation of the adnexa is more important. An adnexal ring is a significant, though not absolute, indicator of ectopic pregnancy. A normal scan excludes this diagnosis. Other criteria were not significant. A clinical approach to the evaluation for ectopic pregnancy, based on the data accumulated in this study, is suggested.     

Pictorial essay: Transabdominal and endovaginal sonography of adnexal masses

Endovaginal sonography is rapidly becoming the diagnostic procedure of choice when evaluating patients with early pregnancy and assessing uterine abnormalities. However, there has been relatively little discussion of endovaginal sonography in the evaluation of adnexal masses. Using endovaginal sonography we studied 50 patients with clinically suspected adnexal masses, in whom transabdominal sonography was either suboptimal or failed to adequately characterize the mass. The purpose of this pictorial essay is to depict the normal anatomy of the ovaries and adnexa and highlight the unique contribution of endovaginal sonography in diagnosing a variety of adnexal masses, including tubal and ovarian lesions.     

Cost effectiveness of pelvic sonogram in the emergency room: Endovaginal vs. transabdominal examination

Ultrasound evaluation of the female pelvis is a valuable tool to diagnose pelvic pathology accurately and rapidly in the emergency room patient. Institutions differ concerning which imaging approach—transabdominal or endovaginal sonography—should be performed first, and when it is appropriate to continue to the other modality. The aim of this randomized and prospective study was to determine the most cost-effective imaging approach to pelvic sonography, without sacrificing diagnostic yield. The results of 120 patient encounters utilizing both imaging methods were as follows. Our study showed that 74% of examinations first performed transabdominally required additional endovaginal evaluation, whereas only 9% of initial examinations by endovaginal sonography required transabdominal examination. Thus, we demonstrated that the total time and expenditure of imaging decreased while we maintained high diagnostic accuracy. We recommend that all female emergency patients being evaluated for pelvic pathology, except those with a palpable pelvic mass or with a bladder that is already full, or those in the second or third trimester or pregnancy, undergo imaging initially by endovaginal sonography and that transabdominal evaluation be used as a complementary examination.     

Abnormal pregnancy: early diagnosis by US and serum chorionic gonadotropin levels

Simultaneous sonography and quantitative serum human chorionic gonadotropin (HCG) levels from 126 women with threatened abortion were compared. Of 56 women with normal outcome, 39 (70%) had a gestation sac greater than or equal to 5 mm in mean sac diameter, and in each case the HCG level was 1,800 milli-international units (mIU/ml) or greater. The serum HCG levels strongly correlated with the gestation sac sizes to a mean sac diameter of 25 mm. Of 70 abnormal pregnancies, 31 demonstrated a gestation sac. Of these, 20 women (65%) had disproportionately low HCG levels relative to sac size, including 12 in whom the HCG level was less than 1,800 mIU/ml. One woman with an early molar pregnancy had a disproportionately elevated HCG level. Correlation of sonograms with a simultaneous measurement of serum HCG level is a useful method for evaluating threatened spontaneous abortion. A disproportionately low HCG level relative to gestation sac size is evidence for an abnormal pregnancy.