Ultrasonography (US) is the preferred screening method for the diagnosis of liver disease and one of the commonly used guides for ablative therapy due to its unique advantages, and in 2008, the American Association for the Study of Liver Diseases (AASLD) recommended ultrasound combined with serum fetoprotein as an ideal screening tool for liver cancer in high-risk populations. Ultrasonography (contrast enhanced ultrasound, CEUS) is a revolutionary breakthrough in the field of ultrasound medicine in recent years, which can show the dynamic perfusion of focal lesions in the liver and greatly improve the diagnosis and differential diagnosis of focal lesions in the liver. Therefore, it has been used more and more widely in the diagnosis and ablation of liver tumors in recent years.
Ultrasound is widely used in liver disease examination because it has the following unique advantages: real-time dynamic observation and clear imaging; Doppler imaging allows real-time observation of lesion blood flow; economical and convenient, easily accepted by patients; no radiological hazards; diagnostic performance of CEUS examination is similar to that of CT or MRI, but the contrast agent is non-nephrotoxic and has fewer allergic reactions. The shortcomings of ultrasound examination are: easy to be interfered by gas and bone, and the sweeping sound window is easily restricted; there are often certain blind areas of sweeping, such as subdiaphragm; in addition, in the background of certain diseases such as fatty liver, ultrasound is easily attenuated, and the deep display is poor.
I. Current situation of ultrasound guidance in liver tumor ablation therapy and its advantages and shortcomings
Ablation of liver tumors is a minimally invasive, simple, economical and effective treatment for liver cancer, and in 2011, AASLD recommended that ablation should be the first choice for early stage liver cancer patients who are not suitable for surgery or liver transplantation. Currently, radiofrequency ablation is the most widely used ablative treatment for liver cancer. Meanwhile, alcohol ablation also plays an important role in the ablation treatment of liver cancer.
In liver interventional ablation therapy, ultrasound guidance is the most convenient and commonly used imaging guidance modality. Compared with other imaging guidance, ultrasound guidance has incomparable advantages in liver tumor ablation treatment, but also some shortcomings, which are mainly introduced as follows
Advantages: safe and accurate, real-time monitoring of the whole process of needle puncture and ablation treatment, which can effectively avoid damaging large blood vessels, bile ducts and important perihepatic organs of the liver and eliminate the blindness of puncture; combined with CEUS technology, CEUS can clearly show the surviving tumor tissues for the observation of lesions before liver tumor ablation treatment, especially for lesions after TACE treatment, which are not affected by the iodine oil deposited in the lesions. CEUS can monitor the ablation foci during the ablation process and evaluate whether the foci are completely ablated immediately after the ablation. At present, ultrasound has formed a complete observation and treatment system from liver cancer screening, early diagnosis, preoperative planning, puncture guidance, ablation process monitoring, immediate efficacy assessment after treatment and postoperative follow-up.
Disadvantages: During the ablation process of liver tumors, gas artifacts are often generated, which interfere with the ablated lesions and their posterior tissues; for lesions located in the blind area of ultrasound scanning, ultrasound cannot be displayed and is difficult to guide accurately; for some lesions located in the subperitoneum and subdiaphragm, the ideal puncture path is often blocked by the lung or gastrointestinal tract, which limits the application of ultrasound guidance; during the ablation process, ultrasound is easily interfered by electromagnetic fields generated by some ablation devices. In the ablation process, ultrasound is susceptible to the interference of electromagnetic fields generated by some ablation devices.
With the development of new ultrasound technology, the application of fusion imaging virtual navigation allows the lesions located in the blind area of ultrasound scanning to be clearly displayed and accurately positioned for guided puncture. The application of artificial thoracic fluid or artificial ascites to separate lesions located under the pericardium or diaphragm from the diaphragm or lesions near the gastrointestinal tract from the gastrointestinal tract not only improves the visualization of lesions, but also provides a safer puncture path and reduces the possible damage to the diaphragm or gastrointestinal tract during the ablation process.
Indications and contraindications of ultrasound-guided liver ablation therapy
The indications for ultrasound-guided liver tumor ablation therapy are wide, and it is generally used for the first treatment of HCC, ICC and MLC, as well as their postoperative recurrent foci and the supplementary treatment of residual foci after TACE. The specific indications are as follows: single nodule with diameter ≤ 6 cm; or multiple nodules with diameter ≤ 3 cm and number ≤ 5;, no portal vein cancer thrombus and extrahepatic organ metastasis; liver function Child grade is generally A or B; platelets > 50×109/L, prothrombin time (PT) < 18s, prothrombin activity > 50%.
Contraindications: liver function Child grade C; obvious jaundice; recalcitrant ascites; those with defective coagulation mechanism or bleeding tendency; those with myocardial infarction and extreme failure; patients who are unconscious or cannot fully cooperate with treatment.
Preoperative examination and preparation
1. Preoperative examination: preoperative blood routine, blood type, liver function, kidney function, blood clotting time, blood sugar, electrolytes, tumor markers (AFP, CEA, CA19-9, etc.), chest X-ray, electrocardiogram, etc.; preoperative biopsy of tumors that do not meet the clinical diagnostic criteria of liver cancer to clarify the pathological types of liver tumors; imaging examinations such as ultrasound, CT or MRI of liver tumors to understand the location, size, shape, and tumor pathology. To understand the location, size, shape and important adjacent tissues around the tumor and determine the safe puncture path.
2. Pre-operative preparation: Pre-operative discussion, according to the actual situation of liver tumor, choose the appropriate anesthesia, ablation apparatus, puncture path and necessary auxiliary means; choose color Doppler ultrasound instrument with high resolution and equipped with puncture guidance device. The patient should fast for more than 6 hours before the operation; explain the specific treatment operation process to the patient before the operation, eliminate their nervousness and sign the operation consent form.
3. Intraoperative operation: according to the location of the lesion, the patient selects the supine or lateral position; connects the cardiac monitor; disinfects the local skin and spreads the towel according to the principle of surgical asepsis; performs intravenous general anesthesia or intravenous analgesia and local anesthesia on the patient; observes the liver and the lesion by ultrasound again, generally selects the intercostal space to puncture the needle, adjusts the angle of the puncture guide wire to make it reach the intended location of the puncture, and the puncture path must avoid the lung, intestine For lesions that cannot be easily displayed by two-dimensional ultrasound, CEUS can be combined to observe and guide the puncture; when using a puncture needle smaller than 17G, direct puncture can be performed; when using a thicker puncture needle larger than 17G, a small skin incision of 2mm~3mm can be made first, and then puncture can be performed through the incision; under the breath-holding state of the patient, after the puncture needle reaches the predetermined position in the lesion, ultrasound can confirm the accuracy of the puncture The ablation can be started; during the ablation process, pay attention to the data of the cardiac monitor and the patient’s status at any time, and observe the changes of the lesion during the ablation in real time under the ultrasound.
Before retiring the needle at the end of ablation, the needle tract should be cauterized while retiring the needle to avoid needle tract implantation transfer and needle tract bleeding; after ablation, the puncture site should be bandaged, and the patient should lie still for 0.5 to 1 hour, and be sent back to the ward for further observation after ultrasound observation of no bleeding and other complications; fasting for one day after the operation, liver protection treatment should be given, and antibiotics can be given if necessary and appropriate.
1.Efficacy assessment after ablation: Imaging methods are generally used to assess the ablation treatment effect of liver tumor after ablation, especially contrast-enhanced imaging methods. At present, CT and MRI enhancement scans are mainly used as the gold standard to assess the ablation effect: no enhancement of ablation foci is complete ablation; on the contrary, abnormal enhancement foci within the ablation foci can be regarded as residual tumor ablation. In recent years, many scholars at home and abroad have adopted the method of CEUS to evaluate the treatment effect after ablation of hepatocellular carcinoma, and found that the evaluation effect of CEUS is similar to that of enhanced CT, which can be used as an alternative to enhanced CT.
CEUS is often poorly displayed due to the interference of gas artifacts in the ablation foci when the ablation effect is evaluated immediately after surgery. After ablation, the tissue around the ablation site is often congested, which usually lasts from 2 weeks to 1 month, and during this period, the congested area may appear as a ring-like hyperenhancement when doing imaging enhancement imaging, which is not easy to identify the residual tumor. Nowadays, one month after ablation is generally used as the time point to evaluate the ablation effect of liver tumor.
Some scholars have also used the method of detecting serum AFP to evaluate the ablation effect. It has been confirmed that although the blood AFP concentration has a certain correlation with liver cancer, its sensitivity and accuracy are not good, and it cannot completely replace imaging as the evaluation standard of liver cancer after ablation, so it is only used as a reference now.
2.Follow-up: After the imaging assessment one month after liver tumor ablation is determined as complete ablation, the follow-up period can be entered. During the follow-up period, imaging means is still the main evaluation standard, and blood AFP is the auxiliary means. The initial follow-up interval is 3-4 months, and when there is no abnormality after 2 years of follow-up, the follow-up interval can be extended appropriately. If abnormal enhancing foci appear around the ablation site during the follow-up period, it can be regarded as local tumor progression, which is mainly caused by very small residual cells and tissues around the ablation site (which often cannot be detected when evaluated one month after ablation), usually after several months of growth progression; if abnormal enhancing foci appear in other liver sites outside the ablation site, it can be regarded as recurrent foci in the liver.
I. Ultrasound-guided ablation therapy for small hepatocellular carcinoma
Small hepatocellular carcinoma refers to single hepatocellular carcinoma with diameter less than 3cm or multiple foci with the sum of diameter less than 3cm. For small hepatocellular carcinoma, the recurrence rate and 5-year survival after ablation are comparable to those of surgical resection, and the liver function reserve can be preserved to a greater extent. Ultrasound-guided hepatocellular carcinoma ablation has been used as the first choice for small hepatocellular carcinoma in some prestigious international medical centers. Generally, one-point ablation or multi-point superimposed ablation can be used, and most lesions can achieve complete ablation.
Typical case 9]
. Brief history: male, 54 years old, underwent partial hepatectomy for HCC 2 months ago, postoperative pathology showed HCC, adenoid type, Edmondson grade III. Further CEUS examination revealed two small recurrent foci of HCC in liver S5 and S6 with diameters of 1.1cm and 1.6cm respectively (Figure A, B), which were to be treated with radiofrequency ablation.
. Ablation strategy and steps
(1) Strategy: The patient was in good general condition, with Child A liver function, no contraindication to radiofrequency ablation, two lesions with diameters of 1.1 cm and 1.6 cm, the lesions were clearly located, and the puncture route was safe.
(2) Steps: ultrasound-guided puncture into liver S5 and S6 lesions (Figure C,D), one needle per lesion, one point of ablation, ablation time 12 min/point, ablation range can completely cover the lesions (Figure E).
Efficacy assessment and follow-up: The maximum diameter of ablated foci in liver S5 and S6 was 3.3cm~4.0cm on ultrasound review in one month after surgery (Figure F,G), and CEUS showed complete ablation of liver S5 and S6 foci (Figure I,J). AFP decreased to 70μg/L.
Figure Ultrasound-guided ablation of small hepatocellular carcinoma
Figure A, B CEUS revealed two recurrent foci of hepatic S5 and S6 with hyperenhancement in the arterial phase; Figure C, D Ultrasound-guided puncture reached the inside of the lesions and started radiofrequency ablation; Figure E Radiofrequency ablation of hepatic S5 lesions produced a large amount of gas artifacts to cover the lesions completely; Figure F, G Two-dimensional ultrasound showed mixed echoes of hepatic S5 and S6 ablation foci; Figure I, J CEUS showed no blood supply of hepatic S5 and S6 ablation foci.
[Typical case 10].
. Brief history: male, 74 years old, hepatitis B virus carrier for more than 10 years, liver nodules were found for 1 week; CT showed hepatic S8 nodules (Figure A), 2.5 cm in diameter; CEUS showed a typical “fast-in-fast-out” HCC presentation (Figure B,C). Ultrasound-guided puncture biopsy pathologically diagnosed hepatocellular hepatocellular carcinoma (Figure D). 66 μg/L AFP.
AFP 66μg/L. Ablation strategy and steps
(1) Strategy: The patient was in good general condition, liver function Child A grade, no contraindication to RF ablation, the location of the lesion was clearly shown, the puncture path was safe (Figure E), the lesion diameter was 2.5 cm, and RITA radiofrequency ablation was to be performed.
(2) Step: 1 needle was punctured into the tumor via ultrasound guidance, and 2 sites were ablated (Figure F).
Efficacy assessment and follow-up: One month postoperative CEUS review revealed complete ablation of the lesion with an ablation focal size of 4.5 cm × 3.2 cm (Figure G). the AFP decreased to 7.87 μg/L. One year postoperative CEUS review revealed complete ablation of the lesion (Figure H).
Figure Ultrasound-guided ablation of small hepatocellular carcinoma
Figure A Enhanced CT venous phase showing hepatic S8 hypoenhancing nodule (white arrow); Figure
Arterial phase (25s) shows hyperenhanced hepatic S8 lesion; Figure C CEUS portal phase (82s) shows hypoenhanced hepatic S8 lesion; Figure D Pathology confirmed as HCC by ultrasound-guided puncture biopsy; Figure E 2D ultrasound shows a clear lesion with a puncture guide line through the center of the lesion and a safe puncture path; Figure F RITA radiofrequency ablation needle (black arrow) punctured into the center of the lesion and started radiofrequency ablation; Figure G One-month postoperative review, CEUS portal phase (37s) showed no enhancement of the ablated foci of liver S8; Figure H One-year postoperative review, CEUS portal phase (52s) showed no enhancement of the ablated foci of liver S8.
Ultrasound-guided ablation therapy for medium and large hepatocellular carcinoma
Medium and large hepatocellular carcinoma often has a large lesion (3-5cm in diameter). Depending on the size of the lesion, single-needle puncture multi-point superimposed ablation, multi-needle puncture multi-point superimposed ablation, or combined radiofrequency and alcohol ablation can be used to achieve a larger ablation range, so that the ablation range can reach 0.5cm-1.0cm around the tumor, which can achieve the effect of complete ablation of the tumor.
Typical case 11]
. Brief history: male, 33 years old, liver transplantation for HCC 3 years ago, chemotherapy after transplantation, lung metastasis found 1 year ago and left lower pneumonectomy, 2-dimensional ultrasound found S4 lesion in transplanted liver half a month ago (Figure A), 6.2 cm in diameter, CEUS showed “fast in-fast out” performance (Figure B, C, D), suggesting giant mass type HCC recurrent foci.
. Ablation strategy and procedure
(1) Strategy: The patient had a recurrence in the transplanted liver after HCC liver transplantation, with good general condition, Child A liver function, no contraindication to RF ablation, the lesion was located in hepatic S4, with clear ultrasound and safe puncture route, and the tumor diameter was 6.2 cm.
(2) Steps: Firstly, a multi-pole alcohol needle was applied to the tumor through ultrasound-guided puncture (Figure E), and the sub-needle was unfolded 3cm sequentially while injecting anhydrous alcohol, and the needle was withdrawn after 30ml of anhydrous alcohol was injected into the tumor and the needle was left for 2 minutes; then a TALON unipolar multi-tip radiofrequency ablation needle was placed into the tumor through ultrasound-guided puncture, and the sub-needle was unfolded 4cm, and a total of 2 needles were punctured to ablate 4 sites, and the ablation time was 48 minutes (Figure F). The ablation time was 48 minutes (Figure F).
Evaluation of efficacy and follow-up: The patient was in good general condition after surgery, and hepatic care was given. The CEUS review at one month after the procedure revealed residual foci around the ablation site (Figure H, white arrow). (See Case 13 for follow-up complementary treatment)
Figure Combined alcohol ablation + radiofrequency ablation for macroscopic HCC
Figure A 2D ultrasound showing a round hypoechoic lesion in the S4 of the transplanted liver; Figure B CEUS arterial phase (19s) with heterogeneous hyperenhancement of the hepatic S4 lesion; Figure
The portal vein phase (56s) and the delayed phase (184s) of Figure D show that the hepatic S4 lesion gradually faded and showed heterogeneous slightly hypoenhancement; Figure E. The ultrasound-guided alcohol treatment needle was punctured into the tumor and injected with alcohol; Figure F. The ultrasound-guided TALON radiofrequency ablation needle was punctured into the tumor and started radiofrequency ablation, and a large amount of gas artifacts were seen in the lesion; Figure G. One month after the ablation, the CEUS showed that there was no enhancement inside the lesion. There was no enhancement inside the lesion, and a residual foci were seen around the lesion.
III. Supplementary ablation therapy after TACE
(
) is to inhibit tumor growth and promote necrosis by embolizing the blood supplying artery of the tumor, which has been widely used because it has shown good efficacy in the treatment of hepatocellular carcinoma. However, for some types of hepatocellular carcinoma, the effect of TACE treatment is often less than ideal, such as highly differentiated HCC or those with extensive intrahepatic arteriovenous fistulae. Ultrasound-guided ablation therapy can further supplement ablation therapy for those with unsatisfactory results after TACE or those with residual lesions, so as to achieve complete necrosis of liver cancer tumor tissue. Because ultrasound is not affected by the iodine oil deposited in the lesion after TACE, the display of the lesion and the guidance of puncture are better than other radiological imaging guidance methods. And combined with the new technology of CEUS, it can detect the tumor biopsies in the lesion and guide the accurate puncture ablation treatment.
[Typical case 12].
. Brief history: male, 78 years old. 4 months ago, a hepatic S7 lesion with a diameter of 4.6 cm was found and pathologically confirmed by puncture biopsy as highly differentiated HCC (Figure A). He was treated with TACE (Figure B), and after TACE, CEUS showed that there was still blood supply in the lesion (Figure C,D,E), so he was treated with ultrasound-guided radiofrequency ablation, and preoperative AFP was 13.25 μg/L.
. Ablation strategy and steps
(1) Strategy: The patient had residual HCC TACE, good general condition, Child B liver function, no contraindication to RF ablation, the lesion was located in liver S7, ultrasound showed clear, safe puncture path, tumor diameter 4.6 cm, in order to make complete ablation of the tumor, the proposed combined treatment of alcohol ablation + RF ablation.
(2) Steps: Firstly, the multi-pole alcohol needle was applied to the tumor through ultrasound-guided puncture (Figure F), and the maximum diameter of the sub-needle was expanded sequentially up to 4 cm while injecting anhydrous alcohol, and the needle was withdrawn after a total of 17 ml of anhydrous alcohol was injected into the tumor; then the TALON unipolar multi-tip radiofrequency ablation needle was placed into the tumor through ultrasound-guided puncture, and the sub-needle was expanded 4 cm, and a total of 1 site was ablated in 12 minutes (Figure G). 12 minutes (Figure G).
Efficacy assessment and follow-up: The patient was in good general condition after surgery and given liver protection. The tumor was completely ablated by CEUS review 3 days after the operation (Figure H,I).
Figure HCC TACE treatment followed by ultrasound-guided supplementary ablation
Figure A Ultrasound-guided puncture biopsy pathology showed HCC with high differentiation; Figure B CT showed round nodules of liver S7 with iodine oil deposits; Figure C 2D ultrasound showed slightly hyperechoic lesions of liver S7 with indistinct borders; Figure D CEUS arterial phase (20s) showed hyperenhancement of liver S7 lesions; Figure E CEUS delayed phase (216s) showed hypoenhancement of liver S7 lesions; Figure F Ultrasound-guided alcohol therapeutic needle (black arrow) Figure G The ultrasound-guided TALON radiofrequency ablation needle was punctured into the tumor and radiofrequency ablation was started, and a large amount of gas artifacts were seen in the lesion; Figure H The two-dimensional ultrasound showed a mixed echogenicity of the lesion on review 3 days after ablation; Figure I The CEUS showed no abnormal enhancement inside and around the lesion 3 days after ablation, and the lesion was completely resolved.
IV. Residual or locally progressing supplementary ablation treatment after ablation
After ablation, two-dimensional ultrasound observation of ablation foci often shows a messy mixed echogenicity, which is not easy to distinguish the demarcation between ablation foci and normal liver tissue or residual lesions. For supplementary ablation treatment of residual foci or LTP after ablation of hepatocellular carcinoma, ultrasonography is often required to determine its location and guide the puncture ablation.
[Typical case 13].
. Brief history: male, 33 years old, (see case 11). He was reviewed one month after alcohol + radiofrequency ablation for recurrent foci of S4 HCC in the transplanted liver and was found to have residual foci at the edge of the ablation foci, which were to be treated with ultrasound-guided ablation of the residual foci.
. Ablation strategy and steps
(1) Strategy: The patient is a residual foci after ablation of S4 HCC recurrent foci in the transplanted liver, with good general condition, Child A liver function, no contraindication to RF ablation, the foci are located at the edge of S4 ablation foci in the transplanted liver, the puncture path is safe, the two-dimensional ultrasound shows that the ablation foci are uneven mixed echogenicity (Figure A), it is impossible to distinguish the ablation foci from the residual foci, it is proposed to observe the residual foci with CEUS first, and then determine their location. It is proposed to observe the residual foci by CEUS first, and then perform ultrasound-guided puncture ablation.
(2) Steps: Firstly, CEUS was performed to observe the ablation foci and determine the location of the residual foci (Figure B), and then 2D ultrasound-guided puncture was performed to the residual foci and TALON radiofrequency ablation treatment was performed (Figure C), with a total of 1 needle puncture and 2 sites ablated in 24 minutes.
Efficacy assessment and follow-up: The general condition of the patient was good after the procedure. The CEUS review at one month after the operation showed complete ablation of the residual foci (Figure D).
Figure Supplementary ablation treatment of residual foci after HCC ablation
Figure A: 2D ultrasound showed mixed echogenicity of the ablated S4 foci in the transplanted liver, and it was impossible to identify the residual foci; Figure B: Highly enhanced residual foci (white arrows) were seen at the edge of the ablated S4 foci in the arterial phase of CEUS (26s); Figure C: RF ablation needle puncture was guided by 2D ultrasound into the residual foci and started ablation; Figure D: 1 month after ablation, CEUS showed no enhancement inside and around the foci, and the residual foci were completely ablated The residual foci were completely ablated.
V. Several auxiliary means of ultrasound-guided ablation therapy
(A) CEUS-guided ablation therapy for liver cancer
CEUS guidance is mainly used for liver tumors that cannot be clearly displayed by 2D ultrasound, such as microscopic liver cancer, highly differentiated HCC, residual foci after ablation or TACE, etc. CEUS guidance can be used to observe the lesion before surgery, determine the location of the lesion under 2D ultrasound, and then perform 2D ultrasound-guided liver tumor ablation therapy; or it can be used to directly puncture under CEUS guidance, observe the location of the lesion during the arterial phase of CEUS, and observe the location of the lesion during the portal vein phase of CEUS. The lesion location, CEUS portal vein phase and delayed phase last longer (>3 minutes), and guided puncture can be performed in this period.
[Typical case 14].
. Brief history: male, 58 years old. recurrent foci of hepatic S6, size 2.3 cm × 1.6 cm, were found on CEUS review after HCC ablation. because the location of the foci could not be identified by 2D ultrasound (Figure A), CEUS-guided radiofrequency ablation was proposed.
. Ablation strategy and steps
(1) Strategy: The patient had recurrent HCC after ablation, good general condition, Child A liver function, no contraindication to radiofrequency ablation, single lesion located in liver S6, maximum diameter 2.3 cm, safe puncture path. Because the lesion could not be identified by 2D ultrasound, CEUS-guided puncture Cool-tip radiofrequency ablation was feasible.
(2) Steps: The location and size of the lesion were observed in the arterial phase of CEUS, and the best puncture path was selected (Figure B). The puncture was guided in the portal and delayed phases of CEUS (Figure C), and the Cool-tip RF ablation needle was applied to puncture into the tumor, with a total of 2 punctures and 2 sites ablated in 12 minutes/site (Figure D). Postoperatively, the patient was in good general condition and was discharged with liver protection therapy.
Efficacy assessment and follow-up: The patient recovered well after surgery with normal liver function indexes and was followed up regularly. On review six months after surgery, CEUS showed complete ablation of the hepatic S6 lesion, with no blood supply and abnormal enhancement of the ablation foci (Figure E, F, G).
Figure A 2D ultrasound showed hepatic S6 ablation foci (white arrows) with heterogeneous echogenicity and no clear recurrent lesions; Figure B CEUS arterial phase (17s) showed recurrent hepatic S6 lesions (white arrows) with high enhancement, and the puncture guide line passed through the center of the lesions; Figure C CEUS portal vein phase (64s) showed recurrent hepatic S6 ablation foci (black arrows) with low enhancement (white arrows) next to the ablation foci; Figure D 2D ultrasound showed recurrent foci (white arrows) via CEUS guide The Cool-tip radiofrequency ablation needle was applied to penetrate into the lesion and start radiofrequency ablation, which produced a large amount of gas artifacts in the lesion; Figure E. Two-dimensional ultrasound showed mixed echogenicity in the ablated foci of liver S6 after the second ablation; Figure F, G. The ablated foci of liver S6 in the arterial phase (26s) and portal vein phase (56s) of CEUS showed no enhancement.
(B) Ultrasound-guided ablation of hepatocellular carcinoma after artificial ascites
When the lesion is close to the dirty surface of the liver under the liver envelope, it is often adjacent to the gastrointestinal tract. In order to avoid accidental penetration of the gastrointestinal tract during the needle puncture or injury to the gastrointestinal tract during thermal ablation, artificial ascites can be implemented before ablation to separate the liver from the gastrointestinal tract before ablation.
[Typical case 15].
. Brief history: male 48 years old, he had hepatitis B minor tri-positive for more than 8 years. 3 months ago, he underwent partial hepatectomy for HCC, and the postoperative pathology confirmed HCC (Figure A), beam cord type, grade II. Now the review revealed recurrent foci of HCC. Ultrasound revealed a hepatic S6 lesion (Figure B and C), measuring 2.3 cm × 1.7 cm.
. Ablation strategy and steps
(1) Strategy: The patient had recurrent hepatocellular carcinoma, good general condition, Child A liver function, and no contraindication to radiofrequency ablation. Because the lesion was located in S6 and close to the intestinal canal, in order to avoid damaging the intestinal canal during thermal ablation, it was proposed to separate the lesion from the intestine by artificial ascites first and then perform radiofrequency ablation.
(2) Steps: Artificial ascites was performed by ultrasound-guided puncture, and after 500 ml of saline was injected into the abdominal cavity, the lesion was clearly separated from the intestinal canal (Figure D), and Cool-tip radiofrequency ablation was performed by ultrasound-guided puncture into the lesion (Figure E), with 3 stitches and 3 sites ablated for a total of 30 minutes.
Efficacy assessment and follow-up: complete ablation of the lesion was found on CEUS review at one month after the procedure (Figure F and G).
Figure Ultrasound-guided ablation of hepatocellular carcinoma after artificial ascites
Figure A Post-operative pathology diagnosis of HCC; Figure B 2D color Doppler ultrasound showed a hyper-echoic liver S6 lesion (white arrow) with internal blood flow signal; Figure C CEUS arterial phase (16s) showed a hyper-enhanced liver S6 lesion (white arrow); Figure D 2D ultrasound showed a complete separation of the liver S6 lesion (white arrow) from the abdominal intestine (black arrow) after artificial ascites; Figure E Ultrasound-guided Cool-tip radiofrequency ablation needle The ablation was started by puncture into the lesion and produced gas artifacts (white arrows); Figure F and G On review at one month after ablation, 2D ultrasound showed mixed echogenicity of the ablated liver S6 lesion (white arrows), and the arterial phase of CEUS (28s) showed no enhancement of the ablated liver S6 lesion (white arrows).
(iii) Ultrasound-guided ablation of hepatocellular carcinoma after artificial pleural fluid
When the lesion is close to the top of the liver diaphragm and is often disturbed by pulmonary gas, resulting in poor display of the lesion, or when the puncture route needs to pass through the chest cavity, artificial pleural fluid technique can be used to clearly display the lesion or provide a new puncture route.
Typical case 16]
. Brief history: Female, 74 years old, one year postoperative lung cancer, liver S1 metastasis with a diameter of 3.0 cm was found, and due to the patient’s age and the deep location of the lesion near the inferior vena cava, surgical resection was abandoned and minimally invasive ablation therapy was proposed.
. Ablation strategy and steps
(1) Strategy: The patient had liver metastasis of lung cancer, good general condition, liver function Child A grade, and no contraindication to radiofrequency ablation. Preoperative ultrasound examination: the lesion was clear, but the best puncture path was blocked by the lower pole of the lung, and the lower pole of the lung might be damaged during ultrasound-guided puncture (Figure A), so it was proposed to first displace the lower pole of the lung by artificial pleural fluid, so as to obtain a safer puncture path before performing radiofrequency ablation.
(2) Step: After ultrasound-guided thoracic puncture of the rib-diaphragmatic angle with artificial chest water, the lower pole of the lung was shifted inward and upward after the injection of 500 ml of saline into the chest cavity, and the ultrasound showed that the puncture guide line went through the rib-diaphragmatic angle filled with chest water to the center of the lesion (Figure B), and the puncture path was safe. The Cool-tip radiofrequency ablation needle was applied, and the ablation was started by ultrasound-guided puncture to the lesion (Figure C), with a total of 1 site ablated in 12 minutes/site.
Figure Ultrasound-guided ablation of hepatocellular carcinoma after artificial pleural fluid
Figure A The ultrasound-guided optimal puncture guidance line passed through the center of the liver S1 lesion (white arrow), while the proximal segment of the puncture guidance line could injure the lower pole of the lung (black arrow); Figure B After successful implementation of artificial pleural fluid, the right thoracic cavity was filled with pleural fluid at the angle of the rib diaphragm (black arrow), and after the lower pole of the lung moved upward, the needle was accurately punctured by ultrasound-guided needle deployment, and the tip of the needle (white arrow) passed through the center of the lesion; Figure C The radiofrequency ablation within the liver S1 lesion produced a large amount of gas artifacts ( black arrow).
(D) Ultrasound virtual navigation-guided ablation of hepatocellular carcinoma
Fusion imaging method, also known as virtual navigation technique. The CT, MRI or 3D ultrasound images are imported into the ultrasound instrument by DICOM, and the CT, MRI or 3D ultrasound tomographic images are matched with the real-time ultrasound images and the same cross-section is obtained with the help of magnetic field spatial position locator. With the help of fusion images, especially enhanced CT or MRI images, it is not only possible to show lesions that are difficult to be shown by ordinary ultrasound, but also to use fusion images to make careful needle planning for larger tumors and improve local treatment effects.
[Typical case 17].
. Brief history: male, 45 years old, 2 months after partial resection of HCC with progressive rise in AFP over 3000 ng/dL. no definite lesion was seen on ultrasonography (Figure A), slightly hypoenhancing lesion in the delayed phase of hepatic S7 with unclear borders was seen on ultrasonography, and hyperenhancing disease in the arterial phase of hepatic S7 was seen on enhanced CT. Radiofrequency ablation therapy was proposed.
. Ablation strategy and steps
(1) Strategy: The patient had recurrent hepatocellular carcinoma, good general condition, liver function
grade, no contraindication to radiofrequency ablation. Because the lesion was located in S7, both ordinary ultrasound and ultrasonography did not show the lesion clearly, while it was clearly shown on enhanced CT. The proposed RF ablation under virtual navigation.
(2) Steps: The CT data was imported into the ultrasound instrument in DICOM format, and after alignment and matching, the CT images could correspond to the real-time ultrasound one by one. Then, the puncture needle was guided to enter inside the tumor under navigation, and the radiofrequency ablation application Cool-tip radiofrequency ablation needle was started. Due to the large diameter of the lesion, multi-point compound ablation treatment with multiple needles was implemented.
Efficacy assessment and follow-up: CECT review at one month after surgery revealed complete ablation of the lesion.
Figure A: Slightly hypoechoic liver S7 segment with unclear lesion contour and boundary on plain ultrasound; slightly hypoenhanced liver S7 lesion with unclear contour (white arrow) on delayed ultrasonography; Figure C: Highly enhanced liver S7 lesion on CECT arterial phase; navigation ultrasound guided RF electrode inserted inside the tumor; Figure E: Ultrasound guided Cool-tip RF ablation needle punctured into the lesion and started ablation and produced gas artifact; Figure F. One-month post-ablation review, CECT arterial phase showed that the ablated foci of liver S7 showed no enhancement, suggesting complete necrosis.
(E) Ultrasound-guided intervention for portal vein cancer thrombosis
The emergence of portal vein cancer thrombus is often a manifestation of middle and late stage of liver cancer, which often deprives patients of the treatment opportunities of liver cancer surgical resection and liver transplantation, and there is no better treatment method other than chemotherapy in the past. At present, ultrasound-guided radioactive particle implantation and alcohol ablation have made some progress in portal vein cancer embolism, which provides an alternative treatment for portal vein cancer embolism.
Typical case 18]
Brief history: male, 68 years old, 10 years after HCC resection with intrahepatic recurrence and 5 days of portal vein tumor embolism detected by ultrasound after multiple HCC radiofrequency ablation (see Case 6 Figure A,B,C).
Ablation strategy and steps
(1) Strategy: The patient had recurrence after HCC and portal vein cancer thrombosis after multiple radiofrequency ablation, with good general condition and liver function Child B grade. Because of portal vein cancer thrombosis, it is not suitable for ultrasound-guided ablation treatment, so it is proposed to perform ultrasound-guided implantation of radioactive 125I particles for palliative treatment, and the preoperative ultrasound observation of the lesion shows clear and safe puncture path.
(2) Procedure: The 18G PTC needle was used to implant a total of 26 radioactive 125I particles into the transverse left branch of portal vein and the sagittal sector of the vein through ultrasound-guided puncture.
Efficacy assessment and follow-up: At 3-month postoperative follow-up, the ultrasound showed that the portal vein cancer thrombus was shrunken and uniformly distributed dotted strong echogenic particles were visible within it (Figure B and C); at 11-month postoperative follow-up, the enhanced CT showed multiple particle distributions in the portal vein, good blood supply to the liver, and contrast diffusion whole liver enhancement in the liver parenchyma (Figure D).
Ultrasound-guided radioactive particle injection for portal vein cancer thrombosis
Figure A Two-dimensional ultrasound clearly showed the cancer thrombus (white arrow) in the portal vein and guided the PTC needle (black arrow) to penetrate into the sagittal part of the portal vein; Figure B and C After portal vein cancer thrombus particle implantation, multiple posterior radioactive particles with acoustic shadow (white arrow) were seen in the cancer thrombus; Figure D Postoperative CT follow-up showed that high-density particles (black arrow) were still visible in the portal vein cancer thrombus.
V. Main complications and prevention
Fever is often associated with hypothermia after liver tumor ablation, generally lower than 38℃, which can return to normal within a few days after surgery without special treatment.
Pain The main manifestation is pain in the liver area, which usually lasts for 12 to 72 hours. After the end of treatment, most patients’ pain is significantly reduced, and a small number of patients with heavy pain can be given painkillers to relieve it.
Bleeding Postoperative bleeding from the needle tract is more common, and the amount of bleeding is generally small and mostly self-limiting. Nowadays, the incidence of bleeding has been significantly reduced by the cautery treatment of the needle tract after ablation, but only a very small number of patients can have serious postoperative bleeding, which can lead to accumulation of blood in the abdominal cavity or intrahepatic hematoma. In case of severe bleeding, emergency blood transfusion can be given.
Infection After ablation of liver tumor, the chance of infection will be increased, so postoperative antibiotics can be given as appropriate. A few serious infections may lead to liver abscess, which needs to be treated with antibiotics plus ultrasound-guided liver abscess placement and drainage.
Typical case 19]
Brief history: male, 55 years old (see case 9), after complete ablation of hepatic S5 lesion, 6 months follow-up, 2D ultrasound showed slightly reduced hepatic S5 ablation (Figure A), maximum diameter 3.1 cm, CEUS showed no LTP around the lesion (Figure B); 8 months follow-up, 2D ultrasound showed increased hepatic S5 ablation (Figure C), maximum diameter 5.2 cm, CEUS showed circumferential high At 9 months follow-up, 2D ultrasound showed complete internal liquefaction of the ablation focus and liver abscess formation (Figure E).
Figure Post-ablation infection
Fig. A and B At 6 months of follow-up after radiofrequency ablation of liver S5, the ablation foci were shrunken and no LTP was seen; Fig. C and D At 8 months of follow-up, the ablation foci of liver S5 increased in size and the peripheral ring hyperenhancement of liver S5 foci was observed in the arterial phase of CEUS; Fig. E At 9 months of follow-up, 2D ultrasound showed complete liquefaction inside the ablation foci and formation of liver abscess.
Bile leak The intrahepatic bile ducts are inevitably damaged during ablation of liver tumors, and most of them are mostly coagulated and occluded after ablation. Only very few bile ducts are damaged during ablation and bile leakage occurs, often as endoleaks forming intrahepatic bile lakes (Figure). The formation of bile lakes may increase the chance of complicating liver abscess, so they should be actively drained to occlude them.
Typical case 20]
Brief history: female, 38 years old, recurrent HCC (S4, S5, S7, S8 multiple foci) was reviewed 1 month after ultrasound-guided alcohol ablation, and CEUS showed complete ablation of all recurrent foci in the liver (Figure A and B). On review 5 months after ablation, ultrasound revealed the formation of bile lakes in the ablated foci of hepatic S5 and S8 (Figure C and D).
Figure Bile lake formation after HCC ablation
Figure A (two-dimensional ultrasound): ablation foci of liver S4, S5, S7 and S8 showed irregular mixed echogenicity with indistinct margins; Figure B (CEUS) showed complete ablation of liver S4, S5, S7 and S8 lesions with no abnormal enhancement around and within the ablation foci.
Figure C (two-dimensional ultrasound) and Figure D (CEUS) show the fusion and liquefaction of the ablation foci of liver S5 and S8, and a large amount of liquid echogenicity can be seen around them, suggesting the formation of bile lake after ablation.
. Portal vein thrombosis When the liver tumor is close to the portal vein or the portal vein is involved during ablation, portal vein thrombosis can occur during ablation treatment, and its incidence is extremely low. When partial portal vein thrombosis is formed, the changes of liver function and ultrasound can be closely observed to observe the patency of portal vein blood flow, and generally portal vein thrombosis can subside on its own within a few weeks.