Ultrasound evaluation of ectopic pregnancy

The combined use of a serum radioimmunoassay pregnancy test and high resolution utrasonography allows a more direct approach to be made in the diagnosis of ectopic pregnancy. It is important for ultrasonographers to understand the limitations of the more readily available immunologic pregnancy tests in order to avoid misinterpreting ultrasonograms in the event that a pregnancy test is either falsely positive or falsely negative. Clinical suspicion is mandatory if the early diagnosis of ectopic pregnancy is to be made. The referring physician should take advantage of the highly accurate information resulting from the combined findings of a positive serum HCG and the ultrasonographic images. If the statistics regarding diagnostic delay and tubal rupture are to be improved, these tests should be obtained when a patient is initially evaluated. It is important to recognize that the ultrasonographic interpretation rests primarily upon the uterine findings. A normal viable intrauterine pregnancy essentially excludes the diagnosis of ectopic pregnancy. Other uterine appearances may result from an early intrauterine pregnancy, an abnormal intrauterine gestational event, or, as in approximately 1 per cent of pregnancies, an ectopic gestation. Subsequent evaluation in suspicious cases may require a variety of tests including serial HCG determinations, repeat ultrasound examination, uterine dilatation and curettage, culdocentesis, or laparoscopy. It is impossible to recommend a specific schematic approach for any given patient. In part, the pattern of management depends upon availability of tests, the presence or absence of adnexal or cul-de-sac findings, and, of course, the clinical status of the patient.U