page_title: Ultrasonography of liver tumors
section_title: Ultrasound monitoring ablative therapies (alcoholization – PEI, radiofrequency ablation – RFA)
hierarchical_section_title: Ultrasonography of liver tumors / Antitumor therapies / Ultrasound monitoring ablative therapies (alcoholization – PEI, radiofrequency ablation – RFA)
caption_attribution_description: English: Ultrasonographic follow-up of incompletely treated hepatocellular carcinoma. See en:Ultrasonography of liver tumors.
context_page_description: Ultrasonography of liver tumors involves two stages: detection and characterization.
  Tumor detection is based on the performance of the method and should include morphometric information and topographic information. The specification of these data is important for staging liver tumors and prognosis.
  Tumor characterization is a complex process based on a sum of criteria leading towards tumor nature definition. Often, other diagnostic procedures, especially interventional ones are no longer necessary. Tumor characterization using the ultrasound method will be based on the following elements: consistency, echogenicity, structure appearance, delineation from adjacent liver parenchyma, elasticity, posterior acoustic enhancement
  effect, the relation with neighboring organs or structures, vasculature
context_section_description: Ablative therapies are considered curative treatments for HCC together with surgical
  resection and liver transplantation and they are indicated for early tumor stages in patients
  with good liver function. Also they are
  successfully applied in the treatment of liver metastases, where surgical resection is
  contraindicated. They are chemical (intratumoral ethanol injection) or thermal
  (radiofrequency, laser or microwave ablation). They are applied in order to obtain a full
  therapeutic response, without affecting liver function. Complete response is locally proved
  by complete tumor necrosis with a safety margin around the tumor.
  2D ultrasound, Doppler ultrasound and especially CEUS can play an important role in pretherapeutic
  staging, particularly when sectional imaging investigations (CT, MRI) provide
  uncertain results or are contraindicated. During the interventional procedure, ultrasound allows guidance of the needle into the tumor. CEUS allows guidance in areas of viable tissue
  and avoids intratumoral necrotic areas. CEUS also allows assessment of therapeutic effect
  immediately post-procedure (with the possibility of reintervention in case of partial response)
  . To accurately assess the effectiveness of treatment it is mandatory to
  compare the tumor diameter before therapy with the ablation area. The volume of damaged
  tissue must be higher than the initial tumor volume. CEUS appearance is that of central nonenhanced
  area showing a peripheral homogeneous hyperenhanced rim due to post-procedure
  inflammation. 24 hours after the procedure the inflammatory peripheral rim is thinning and
  the necrotic area appears larger than at the previous examination. Thus, a possible residual
  tumor may appear more evident. Residual tumor has poorly defined edges, irregular shape,
  and the tumor diameter is unchanged. Residual tumor tissue is evidenced at the periphery of
  the tumor as an eccentric area behaving as the original tumor at CEUS examination, with
  arterial hyperenhancement and portal and late wash-out. Ultrasound examination 24 hours
  after the procedure, including CEUS, can show apart from the character of the lesion any
  potential post-intervention complications (e.g. active bleeding).
  In the first days after RFA both CEUS and spiral CT have low sensitivity in assessing
  therapeutic efficacy. CT sensitivity 24 hours post-therapy is reported to be even lower than
  CEUS. Difficulties in CEUS examination result from post-lesion
  hyperemia, presence of intratumoral air, ultrasound limitations (too deep lesion or the
  presence of fatty liver) or lack of patient's cooperation (immediately after therapy). For this
  reasons contrast imaging (CT or CEUS) control should be performed one month after
  ablation to confirm the result of the therapy.
  Local recurrence is defined as recurrence of a hyperenhanced area at tumor periphery in the
  arterial phase, with portal and late wash-out. Sometimes, especially for HCC treated by
  alcoholization (PEI) hyperenhanced septa or vessels can be shown inside the lesion.
  In case of successful treatment, US monitoring using CEUS is performed every three
  months. Although CE-CT and/or MRI are considered the method of choice in post-therapy
  monitoring, CEUS can be used in follow-up protocols, its diagnostic
  accuracy being equivalent to that of CE-CT or MRI.
caption: Fig. 13. Assessment of therapeutic efficacy on ultrasound (2D, CFM, CEUS). US exam shows vascular Doppler signal at CFM (left) and CEUS examination reveals incomplete therapy (right).
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