Combined use of serum HCG and sonography in the diagnosis of ectopic pregnancy.

During an 18 month period, 320 patients were referred with clinical suspicion of an ectopic pregnancy. This study is based on 19 patients with ectopic pregnancy who had both a sonographic examination of the pelvis and determination of serum beta human chorionic gonadotropin (HCG) before surgery. Emphasis is focused on the spectrum of sonographic appearances that may occur in ectopic gestation. These are illustrated, and the sonographic criteria that have been used both for a positive diagnosis and for the exclusion of ectopic pregnancy in the past are analyzed. It is suggested that the accuracy of sonography can be increased by determining the serum HCG level on the day of the scan and by interpreting the findings with reference to the discriminatory HCG zone.