Diagnostic ultrasound ( PDFDrive )

CHAPTER 30 The First Trimester 1075
A
B
FIG. 30.34 Cesarean Scar Implantation. (A) TAS at 7 weeks’ gestation shows a sac (white arrow) in the anterior lower uterine segment, far
from the uterine fundus (black arrow). (B) TVS shows the sac in the region of the c-section scar with an embryo (calipers) and yolk sac. No
myometrium is visualized anterior to the sac. See also Video 30.8.
A
B
FIG. 30.35 Abdominal Ectopic Pregnancy. A 19-year-old woman with acute abdominal pain and syncope. (A) Sagittal TAS demonstrates a
mildly enlarged uterus with an endometrial cavity distended with blood. Blood is also seen surrounding the uterus (arrows). (B) TAS superior to
the uterine fundus demonstrates a 15-week abdominal ectopic pregnancy. Surgical treatment conirmed abdominal ectopic secondary to uterine
rupture caused by an interstitial ectopic pregnancy.
Pregnancy of Unknown Location
In irst-trimester patients, the initial TVS correctly identiies the
site of in over 90% of patients. 106 In the absence of a well-deined
IUP, or in the absence of an ectopic pregnancy, other indings
can suggest the location of the implantation but are nonspeciic
and can result in diagnostic error. Recently, women with a positive
pregnancy test who have no evidence of either an IUP or ectopic
pregnancy on TVS have been categorized as having pregnancy
of unknown location (PUL). 122,123 he diferential diagnosis for
PUL includes a very early IUP, an abnormal IUP, spontaneous
miscarriage, and ectopic pregnancy. 124 he proportion of patients
categorized as PUL depends on gestational age at examination
(and of course depends on the quality of the scan and expertise
of the imager).
In a series of 5318 unselected women in the irst trimester,
456 (8.7%) were classiied as PUL. 106 Of the 456 patients classiied
as PUL, 31 (6.8%) had ectopic pregnancies. he PUL group
beneits from close follow-up because of their high incidence of
ectopic pregnancy. Kirk et al. 106 showed that a single TVS examination
correctly diagnosed ectopic pregnancy in 96.1% of patients
undergoing surgical management. herefore 3.9% of patients
diagnosed with ectopic pregnancy and treated nonsurgically
could have normal or abnormal IUPs. hus it is important to
consider the clinical history and presentation before using
nonspeciic parameters in the management of patients with ectopic
pregnancy.
Management
he conventional management of ectopic pregnancy has been
surgical, with resection of the diseased tube. Improved diagnostic
capabilities, including TVS, allow for earlier diagnosis and the
potential for a more conservative approach to treatment. he