Diagnostic ultrasound ( PDFDrive )

106 PART II Abdominal and Pelvic Sonography
A
B
C
D
FIG. 4.41 Early Arterial Phase Vascular Morphology. Shown on real-time dynamic ultrasound, this is contributory to diagnosis of focal liver
masses. (A) Stellate vessels are highly suggestive of focal nodular hyperplasia. (B) Peripheral discontinuous nodular enhancement without linear
vascularity suggests hemangioma. (C) Rim enhancement has a high association with malignant disease, especially metastases and cholangiocarcinoma.
(D) Dysmorphic tortuous vessels are suggestive of malignant tumors, in this case a hepatocellular carcinoma. The illing from the
periphery, as here, is common for this diagnosis.
technique, performed either at wash-in of contrast or at the peak
of arterial phase enhancement, a brief high-MI exposure will
destroy all the bubbles within the FOV. Sequential frames, as
the lesion and liver are reperfused, will track the bubble course
providing exquisite resolution (Fig. 4.42, Videos 4.5 and 4.6).
here are established algorithms for the diagnosis of focal
liver masses with CEUS, with similarities to CT and MRI
algorithms but also important diferences 131-133 (Table 4.3).
Diagnosis of benign liver masses, hemangioma, and focal
nodular hyperplasia (FNH) is extremely accurate showing
characteristic features of enhancement in the arterial phase and
sustained enhancement in the portal venous phase (Fig. 4.43),
such that their enhancement equals or exceeds the enhancement
of the adjacent liver. Malignant tumors, by comparison, tend
to show washout, such that the tumor appears unenhanced in
the portal venous phase of enhancement (Fig. 4.44). Exceptions
to this general rule include frequent washout of benign hepatic
adenoma and delayed or no washout of HCC. Discrimination
of benign and malignant liver masses has similar high
accuracy. 134
Liver Mass Detection
Excellent spatial resolution allows small lesions to be well seen
on sonography. herefore it is not size but echogenicity that