Diagnostic ultrasound ( PDFDrive )

508 PART II Abdominal and Pelvic Sonography
P
U
FIG. 14.7 Hemoperitoneum in Ruptured Ectopic Pregnancy. Oblique
transverse TVS of the left adnexa shows particulate free luid (P).
FIG. 14.9 Pelvic Hematoma 2 Days After Surgery in Female Patient
Taking Anticoagulants. Sagittal TVS image shows the uterus (U), with
luid in the endometrial canal, surrounded by a large, hypoechoic
heterogeneous hematoma (arrowheads).
FIG. 14.8 Blood Clot. Acute blood clot secondary to rupture of a
pseudoaneurysm at the hepatic artery anastomosis after liver transplantation.
Sagittal ultrasound image of the left lower quadrant shows a solid,
heterogeneous mass (calipers).
a time. Massive hemorrhage oten results in a large, echogenic
mass that may become more heterogeneous as lysis occurs over
time (Figs. 14.8 and 14.9).
Focused abdominal sonography for trauma (FAST) has
become an accepted screening modality for intraabdominal
injuries in the traumatized patient. 19-23 he primary focus of this
limited study is to detect free intraperitoneal luid with ultrasound
in the trauma center. Fluid detected in this setting strongly
suggests signiicant intraabdominal injury requiring urgent
laparotomy. FAST has replaced peritoneal lavage in many centers.
Chylous ascites is an unusual condition in which lymph
accumulates within the peritoneal cavity. he causes are varied,
including trauma, surgery, lymphangioma, lymphoma, intestinal
lymphangiectasia, and cystic hygroma. Sonography may
show particulate ascites or a luid-luid level because of layering
of the lymphatic luid. 24,25
It is sometimes diicult to decide if luid visualized in the
peritoneal cavity is free or loculated. Altering the patient’s position
may be helpful to establish if the luid moves under the force of
gravity. For example, free luid in the right paracolic gutter with
the patient lying supine may move from this location if the patient
lies in a let lateral decubitus position. he morphology of the
luid collection may also be helpful. Free luid tends to conform
to the surrounding organs and will frequently exhibit acute angles
when in contact with surrounding structures such as bowel loops.
Loculated luid, on the other hand, tends to have rounded
margins and show mass efect, frequently displacing surrounding
structures from their usual location. Loculated luid collections
can occur anywhere in the abdomen and pelvis. Characterization
of luid and the demonstration of complexity of localized or
generalized peritoneal luid collections are strengths of ultrasound,
and ultrasound is superior to CT scan in this regard (Fig. 14.10).
PERITONEAL INCLUSION CYSTS
(BENIGN ENCYSTED FLUID)
he luid produced by active ovaries in premenopausal patients
is usually absorbed by the peritoneum. his balance can be upset
by disease processes involving the pelvis, such as previous surgery,
trauma, pelvic inlammatory disease, inlammatory bowel
disease, or endometriosis. In these patients the luid produced
by the ovaries may not be absorbed but may become trapped
by adhesions. Over time, an inclusion cyst forms that frequently
encases the ovary and may cause pelvic pain and pressure.
Inclusion cysts vary in size and complexity and may be relatively
simple or may contain internal echoes and septations. 26-28 hey
oten cause confusion when imaging is performed and may be