Diagnostic ultrasound ( PDFDrive )

CHAPTER 15 The Uterus 557
A
B
C
FIG. 15.29 Post–Cesarean Section Findings. (A) Normal lower
uterine segment indings. Sagittal TVS 3 weeks after cesarean delivery
shows echogenic areas (arrow) in the lower uterine segment due to
sutures. (B) Sagittal TVS several weeks after cesarean delivery shows
a heterogeneous mass (H) in the lower uterine segment anteriorly
due to a bladder lap hematoma. See also Video 15.13. (C) Subfascial
hematoma. Sagittal midline image from TAS in a patient with a
signiicant hematocrit drop after cesarean section. There is a large
heterogeneous mass anterior to the uterus, due to a subfascial
hematoma (H). (C reproduced with permission from Brown DL. Pelvic
ultrasound in the postabortion and postpartum patient. Ultrasound
Q. 2005;21(1):27-37. 190 )
signiicant. he size above which hematomas tend to be clinically
important is uncertain, although it has been suggested that
hematomas smaller than 4 cm 202 are unlikely to be clinically
signiicant. Subfascial hematomas are thought to be due to
disruption of inferior epigastric vessels and are located extraperitoneally.
203 hey can appear as a mass of variable echogenicity,
located posterior to the rectus abdominal muscles of the lower
abdominal wall (see Fig. 15.29C). Subfascial and bladder lap
hematomas may occur in the same patient, but it is important
to distinguish them if surgical treatment is planned, because the
approach is diferent. 203,204
Ater several months, when healing is complete, a thin linear
echo representing the hysterotomy scar can oten be seen in the
lower uterine segment 205 and is a normal, expected inding (Fig.
15.30A). More than one scar may be seen in patients with multiple
prior cesarean deliveries. he myometrium superior to the scar,
or between two adjacent scars, may have a convex outer contour
and potentially be mistaken for a leiomyoma 204,206 (Fig. 15.30B–C).
Fluid sometimes accumulates in the scar, either spontaneously
or during SHG. Variable terminology has been used to describe
this collection of luid in the scar: cesarean scar diverticuli,
cesarean scar pouch, cesarean scar defect, uterine niche, and
isthmocele. 207-211 In general, this entity is considered present
when luid extends into a triangular defect in the anterior lower
uterine segment (Fig. 15.30D); however, there is no standard
deinition. 211 It is also unclear whether such a “defect” is necessarily
abnormal because many patients are asymptomatic. 211 However,
these may cause intermenstrual bleeding and can be treated
surgically. 211 Cesarean scar defects might also be a cause of
dysmenorrhea, chronic pelvic pain, or infertility. 211 Larger defects,
with thinner myometrium, seem to be associated with a higher
likelihood of uterine rupture or dehiscence in a subsequent
pregnancy, but it is not yet clear how this should afect clinical
practice. 212