Past,present,and future perspectives of ultrasound-guided ablation of liver tumors:Where could artificial intelligence lead interventional oncology?

The first ablation procedures for small hepatocellular carcinomas were percutaneous ethanol injection under ultrasound(US)guidance.Later,radiofrequency ablation was shown to achieve larger coagulation areas than percutaneous ethanol injection and became the most used ablation technique worldwide.In the past decade,microwave ablation systems have achieved larger ablation areas than radiofrequency ablation,suggesting that the 3-cm barrier could be broken in the treatment of liver tumors.Likewise,US techniques to guide percutaneous ablation have seen important progress.Contrast-enhanced US(CEUS)can define and target the tumor better than US and can assess the size of the ablation area after the procedure,which allows immediate retreatment of the residual tumor foci.Furthermore,fusion imaging fuses real-time US images with computed tomography or magnetic resonance imaging with significant improvements in detecting and targeting lesions with low conspicuity on CEUS.Recently,software powered by artificial intelligence has been developed to allow three-dimensional segmentation and reconstruction of the anatomical structures,aiding in procedure planning,assessing ablation completeness,and targeting the residual viable foci with greater precision than CEUS.Hopefully,this could lead to the ablation of tumors up to 5-7 cm in size.

Laser ablation of liver tumors:An ancillary technique,or an alternative to radiofrequency and microwave?

Radiofrequency ablation(RFA) is currently the most popular and used ablation modality for the treatment ofnon surgical patients with primary and secondary liver tumors, but in the last years microwave ablation(MWA) is being technically improved and widely rediscovered for clinical use. Laser thermal ablation(LTA) is by far less investigated and used than RFA and MWA, but the available data on its effectiveness and safety are quite good and comparable to those of RFA and MWA. All the three hyperthermia-based ablative techniques, when performed by skilled operators, can successfully treat all liver tumors eligible for thermal ablation, and to date in most centers of interventional oncology or interventional radiology the choice of the technique usually depends on the physician's preference and experience, or technical availability. However, RFA, MWA, and LTA have peculiar advantages and limitations that can make each of them more suitable than the other ones to treat patients and tumors with different characteristics. When all the three thermal ablation techniques are available, the choice among RFA, MWA, and LTA should be guided by their advantages and disadvantages, number, size, and location of the liver nodules, and cost-saving considerations, in order to give patients the best treatment option.

Liver-directed therapies for liver metastases from neuroendocrine neoplasms:Can laser ablation play any role?

Aggressive cytoreduction can prolong survival in patients with unresectable liver metastases(LM)from neuroendocrine neoplasms(NEN),and minimally invasive,liver-directed therapies are gaining increasing interest.Catheter-based treatments are used in disseminated disease,whereas ablation techniques are usually indicated when the number of LM is limited.Although radiofrequency ablation(RFA)is by far the most used ablative technique,the goal of this opinion review is to explore the potential role of laser ablation(LA)in the treatment of LM from NEN.LA uses thinner needles than RFA,and this is an advantage when the tumors are in at-risk locations.Moreover,the multi-fiber technique enables the use of one to four laser fibers at once,and each fiber provides an almost spherical thermal lesion of 12-15 mm in diameter.Such a characteristic enables to tailor the size of each thermal lesion to the size of each tumor,sparing the liver parenchyma more than any other liver-directed therapy,and allowing for repeated treatments with low risk of liver failure.A recent retrospective study reporting the largest series of LM treated with LA documents both safety and effectiveness of LA,that can play a useful role in the multimodality approach to LM from NEN.

Resection vs thermal ablation of small hepatocellular carcinoma:What's the first choice?

Nowadays,hepatocellular carcinoma(HCC) is frequently diagnosed at an early stage,opening good perspectives to radical treatment by means of liver transplantation,surgical resection,or percutaneous ablation.Liver transplantation is considered the best option,but the lack of liver donors represents a major limitation.Therefore,surgical resection,offering a 5-year-survival rate of over 50%,is considered the first-choice treatment for patients with early stage HCC,whereas percutaneous ablation is usually reserved to patients who are not candidate to surgery.However,in the recent years some trials showed that percutaneous radiofrequency ablation(RFA) can be as effective as surgical resection in terms of overall survival and recurrencefree survival rates in patients with small HCC,and a retrospective comparative study reported 1-,3-,and 5-year overall survival rates and recurrence-free survival rates significantly better in patients with central HCC measuring 2 cm or smaller treated with RFA than in those treated with surgical resection.RFA is less expensive,less invasive,with lower complication rate and shorter hospital stay than surgical resection,and on the basis of the results of these studies it should be considered the first option in the treatment of very early HCC.However,RFA is size-dependent,so at present the need to achieve an adequate safety margin around the tumor limits to about 2 cm the diameter of the nodules that can be ablated with long-term outcomes comparable to or better than surgical resection.The main goal of the next technical developments of the thermal ablation systems should be the achievement of larger ablation areas with a single needle insertion.In this regard,the recent improvements in microwave energy delivery systems seem to open interesting perspectives to percutaneous microwave ablation,which could become the ablation technique of choice in the next future.

Contrast-enhanced ultrasonography in peripheral lung consolidations: What's its actual role?

AIM:To evaluate the diagnostic accuracy of contrastenhanced ultrasonography(CEUS)in the differential diagnosis between neoplastic and non-neoplastic peripheral pleuro-pulmonary lesions.METHODS:One hundred patients with pleural or peripheral pulmonary lesions underwent thoracic CEUS.An 8 microliters/mL solution of sulfur hexafluoride microbubbles stabilized by a phospholipid shell(SonoVue)was used as US contrast agent.The clips were stored and independently reviewed by two readers,who recorded the following parameters:presence/absence of arterial enhancement,time to enhancement(TE),extent of enhancement(EE),pattern of enhancement(PE),presence/absence of wash-out,time to wash-out,and extent of wash-out.After the final diagnosis(based on histopathologic findings or follow-up of at least 15 mo)was reached,sensitivity,specificity,positive predictive value(PPV),negative predictive value(NPV),positive likelihood ratio(PLR),negative likelihood ratio(NLR)of each CEUS parameter in the differential diagnosis between neoplastic and nonneoplastic lesions were calculated.Furthermore,an arbitrary score based on the ratio between the PPVs of each CEUS parameter was calculated,to evaluate if some relationship could exist between overall CEUS behaviour and neoplastic or non-neoplastic nature of the lesions.

在 Krukenberg 肿瘤的一种情况中的 ultrasonography 和提高对比的 ultrasonography 的角色

We report a case of Krukenberg tumor of gastric origin with adnexal metastasis,in which ultrasonography(US) and contrast-enhanced US(CEUS) played a key diagnostic role.An 64-year-old female patient was referred to our department for abdominal pain,nausea and ascites.US examination was performed as first line diagnostic imaging approach,confirming the presence of ascites and detecting marked thickness of the gastric wall and a right adnexal mass.CEUS was immediately performed and showed arterial enhancement followed by wash-out in the venous phase of both the gastric wall and the adnexal mass,suggesting the diagnosis of gastric cancer with right adnexal metastasis(Krukenberg syndrome).The patient underwent USguided paracentesis and esophagogastroduodenoscopy that showed linitis plastica.Cytologic examination of the peritoneal fluid revealed the presence of signetring cells,and histologic examination of the specimen obtained by endoscopic biopsy showed primary gastric mucus-producing adenocarcinoma with signetring cells.Although transvaginal US is undoubtedly the method of choice to evaluate ovarian tumors,abdominal US and CEUS can provide key diagnostic elements,supporting clinicians in the first steps of the diagnostic work-up of abdominal and pelvic masses.

Thermal ablation in colorectal liver metastases: Lack of evidence or lack of capability to prove the evidence?

Many studies suggest that combined multimodality treatments including ablative therapies may achieve better outcomes than systemic chemotherapy alone in patients with colorectal liver metastases. Nevertheless,ablative therapies are not yet considered as effective options because their efficacy has never been proved by randomized controlled trials(RCT). However, there are in literature no trials that failed in demonstrating the effectiveness of ablative treatments: what are lacking, are the trials. All the attempts to organize phase Ⅲ studies on this topic failed as a result of non accrual. Just one prospective RCT comparing radiofrequency ablation combined with systemic chemotherapy vs chemotherapy alone has been published. It was designed as a phase Ⅲ study, but it was closed early because of slow accrual, and was downscaled to phase Ⅱ study, with the consequent limits in drawing definite conclusions on the benefit of combined treatment. However, the combination treatment met the primary end point of the study and obtained a significantly higher 3-year progression-free survival than systemic chemotherapy alone. It is very unlikely that ultimate efficacy of ablation treatments will ever be tested again, and the best available evidence points toward a benefit for the combination strategy using ablative treatments and chemotherapy.

Radiofrequency,microwave,and laser ablation of liver tumors:time to move toward a tailored ablation technique?

INTRODUCTION Primary and secondary hepatic tumors are quite common and constitute a significant source of mortality.Primary liver cancer is the fifth most common cancer worldwide and the third most common cause of cancer mortality,and secondary involvement of the liver,particularly from colorectal carcinoma,is even more common.

Hemorrhagic cardiac tamponade after percutaneous laser ablation of a liver metastasis in segment II

Despite percutaneous laser thermal ablation(LTA)of liver tumors being regarded as a safe technique,major complications can occur.We report the first case of hemorrhagic cardiac tamponade after LTA of a colorectal metastasis in segment II of the liver.Unpredictable heat diffusion causing indirect thermal injury to the pericardium with resultant hemorrhagic reaction was hypothesized as the most likely cause of tamponade.A pericardial drain was emergently placed,200 mL of bright red blood were drained,and the patient showed rapid hemodynamic improvement.For lesions located in segment II of the liver and strictly close to the pericardium,a careful risk/benefit analysis should be made by the multidisciplinary team to identify the best treatment option,taking into account both effectiveness and complications of each available technique.

Comment on “Preliminary outcome of microwave ablation of hepatocellular carcinoma: breaking the 3-cm barrier?”

Thamtorawat S,Hicks R,Yu J,Siripongsakun S,Lin WC,Raman S,McWilliams JP,Douek M,Bahrami S,Lu DSK.Preliminary outcome of Microwave ablation of hepatocellular carcinoma:breaking the 3-cm barrier?

Microwave coagulation therapy: the future is quite rosy

We read with great interest the review of Guan[1]on microwave coagulation therapy(MCT)of hepatocellular carcinoma(HCC),and we strongly agree with his conclusion that MCT has a great promise for future use,especially with further technical improvements.