KINESIOL 1Y03 Lecture Notes - Lecture 27: Metastasis, Portal Vein Thrombosis, Microbubbles
23 Jun 2018
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Microbubble Ultrasound
Contrast-enhanced Ultrasound (CEUS) is an important imaging technique for the liver
it is used for:
1) detection of focal liver lesions
2) characterization of focal liver lesions
3) periprocedural monitoring of ablative therapy
Microbubbles are administered IV
Microbubbles consist of gas inside a shell
Inside there can be air, or a heavy molecular mass gas e.g. a perfluoruocarbon,
which has a lower solubility and diffusion coefficient
The shell can consist of lipid, surfactant, albumin or PBCA
Typically 2-6microns in size
Have transpulmonery stability
Are trapped in liver sinusoids
New contrast agents are constantly evolving
1) detection of focal liver lesions
Indications in detection of focal liver lesions
All USS to rule out abscesses/malignancies unless conventional USS clearly shows a
mass
To assess number and locations of mets alongside CT/MR to plan for treatment
Surveillance of oncology patients where it has previously been useful
Suspected cholangiocarcinoma
Small hepatic lesions
Studies show incidental lesions (<1cm) are much more likely to be benign, but up to 11.6%
can be malignant –Schwartz et al 1999
However, the incidence of incidental lesions is underestimated, due to weaknesses of CT and
MRI:
X- lesions are too small
X- partial voluming effect
X- enhancing effects are not in real time
2) Characterisation of focal liver lesions
Hepatic Haemodynamics
Normal: 20-33% supplied by hepatic artery whilst 70% supplies by hepatic portal vein
large tumours supplied almost all by hepatic A
in cirrhosis lack of portal vein flow increases proportion of hepatic A function
SonoVue kinetic profiling can be used to study perfusion; a 2.4ml dose is
administered and the repeated sweeping of the lesion whilst it is being passed
through is done; repeat SonoVue dose can be used if necessary; low MI technique
and non-linear imaging mode required.
Imaging in the arterial phase, portal vein phase and late phase gives rise to a
diagnosis SonoVue study –Leen 2006: found SonoVue improved determination of
diagnosis, accuracy, and decreased need for further MRI in 127 patients giving an
overall saving of £19, 997, compared with conventional USS
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Contrast-enhanced ultrasound (ceus) is an important imaging technique for the liver. It is used for: detection of focal liver lesions, characterization of focal liver lesions, periprocedural monitoring of ablative therapy. Microbubbles consist of gas inside a shell. Inside there can be air, or a heavy molecular mass gas e. g. a perfluoruocarbon, which has a lower solubility and diffusion coefficient. The shell can consist of lipid, surfactant, albumin or pbca. New contrast agents are constantly evolving: detection of focal liver lesions. All uss to rule out abscesses/malignancies unless conventional uss clearly shows a mass. To assess number and locations of mets alongside ct/mr to plan for treatment. Surveillance of oncology patients where it has previously been useful. Studies show incidental lesions (<1cm) are much more likely to be benign, but up to 11. 6% can be malignant schwartz et al 1999. However, the incidence of incidental lesions is underestimated, due to weaknesses of ct and.
