Diagnostic ultrasound ( PDFDrive )

CHAPTER 5 The Spleen 161
L
S
U
B
FIG. 5.34 Wandering Spleen. Sagittal extended–ield of view image of midline abdomen in asymptomatic young woman. B, Bladder; L, liver,
S, spleen; U, uterus.
A
B
FIG. 5.35 Pancreatic Tail Simulating Mass. (A) Sonogram shows 2-cm lesion adjacent to the splenic hilum (arrow). (B) Computed tomography
scan shows that “lesion” is the normal pancreatic tail (arrow).
with technetium-labeled heat-damaged red blood cells, is the
most sensitive study for both posttraumatic splenosis and
congenital polysplenia. Accessory spleens as small as 1 cm can
be demonstrated by this method. 87
INTERVENTIONAL PROCEDURES
Multiple reports and case series have described percutaneous
splenic interventions. 93,94 Although typically described in smaller
series, safety and success rates are similar to those performed
elsewhere in the abdomen. 95
Ultrasound-guided splenic biopsy can help establish a
diagnosis with a low rate of complication rates and a high
diagnostic yield. 24 Fine-needle and core-needle biopsies have
been performed successfully to diagnose focal abnormalities,
including abscesses, sarcoidosis, primary splenic malignancies,
metastases, and lymphoma. 96,97
In patients with abscesses, cysts, hematomas, and infected
necrotic tumors, percutaneous catheter drainage is oten successful.
46 Even radiofrequency ablation (RFA) procedures involving
the spleen have been reported. 98
Despite these reports, however, many interventional radiologists
remain reluctant to perform splenic interventions. he main
concern has been fear of bleeding caused by the highly vascular
nature of the organ. However, clinicians should take into consideration
that a successful image-guided percutaneous procedure
could prevent the need for splenectomy. 95
PITFALLS IN INTERPRETATION
Sonographers must be wary of several ultrasound pitfalls when
scanning the LUQ and spleen. he irst is the crescentic, echo-poor
area superior to the spleen, which can be caused by the let lobe
of the liver in thin individuals 99-102 (see Fig. 5.6). he let liver
lobe can mimic the appearance of a subcapsular hematoma or
a subphrenic abscess. Observing the liver sliding over the more
echogenic spleen during quiet respiration can lead to the correct
diagnosis. Hepatic and portal veins may help to identify this
structure as the liver.
he tail of the pancreas may simulate a mass adjacent to the
hilum of the spleen (Fig. 5.35). his is particularly true if the
plane of section is aimed along the long axis of the pancreatic