Diagnostic ultrasound ( PDFDrive )

130 PART II Abdominal and Pelvic Sonography
A
B
C
D
FIG. 4.64 Timing of Washout. This 49-year-old man had proven metastasis from colon cancer. (A) Axial computer tomography image shows
a low-attenuation mass in the lateral segment of the left lobe. (B) Baseline sonogram shows that the mass is slightly exophytic and of mixed
echogenicity. (C) Contrast-enhanced ultrasound arterial phase image at the peak of enhancement shows hypervascularity. (D) Image at 45 seconds
shows clear washout of the lesion, which had begun at 28 seconds. See also Videos 4.12, 4.13, and 4.14. (With permission from Wilson S, Burns
P. Microbubble-enhanced US in body imaging: what role? Radiology. 2010;257[1]:24-39. 148 )
initially perform abdominal CT to assess the extent of liver trauma.
Ultrasound may be used for serial monitoring of the healing
pattern. In certain circumstances ultrasound can be used as a
screening tool in blunt abdominal trauma (focused assessment
with sonography in trauma [FAST]) by assessing for free luid
that would indicate solid organ injury. 210-214
he predominant site of hepatic injury in blunt trauma is the
right lobe, in particular the posterior segment. 215 Foley et al. 216
found that the most common type of injury was a perivascular
laceration paralleling branches of the right and middle hepatic
veins and the anterior and posterior branches of the right portal
vein. Other indings were subcapsular, pericapsular, and isolated
hematomas; liver fracture, deined as a laceration extending
between two visceral surfaces; lacerations involving the let lobe;
and hemoperitoneum 216 (Fig. 4.65). Hepatic infarcts are rarely
identiied ater blunt abdominal trauma because of the dual blood
supply of the liver.
VanSonnenberg et al. 217 evaluated the sonographic indings
of acute trauma to the liver (<24 hours ater injury or transhepatic
cholangiogram) and determined that fresh hemorrhage
was echogenic. Within the irst week, the hepatic laceration
becomes more hypoechoic and distinct as a result of resorption
of devitalized tissue and ingress of interstitial luid. Ater 2 to 3
weeks, the laceration becomes increasingly indistinct because
of luid resorption and illing of the spaces with granulation
tissue.
Portosystemic Shunts
Surgical portosystemic shunts are performed to decompress the
portal system in patients with portal hypertension. he most