Percutaneous treatment of small hepatic tumors by an expandable RF needle electrode

Efficacy and safety of radiofrequency ablation in the treatment of inoperable patients with pulmonary malignant nodules

BACKGROUND

Radiofrequency ablation (RFA) has been recently applied as an alternative treatment in the patients with pulmonary malignancies. The aim of our study was to assess the incidence of complications and survival rate of RFA for malignant lung nodules, and evaluate the efficacy and safety of RFA in the treatment of inoperable patients with pulmonary malignant nodules.

METHODS

The clinical data of 50 patients with primary and metastatic lung malignant nodules treated with RFA from June 2015 and July 2017 in Hebei General Hospital were considered, and the characteristics and clinical data of these patients were analysed. Complications, progression-free survival and overall survival at 1, 2 and 5 years of these patients were evaluated.

RESULTS

Following the procedure. There were no major complications and deaths during the operation. 26 (52%) patients presented mild-to-moderate chest pain that was easily controlled by analgesic drugs. 8 (16%) patients with pneumothorax, 4 (8%) haemoptysis, 6 (12%) pneumonia, 7 (14%) pleural effusion and 1 (2%) postoperative bronchopleural fistula. Needle-track implantation was observed in 2 (4%) patients. Median progression-free survival (PFS) was 24.6 months. The PFS at 1, 2, 5 years was 76%, 52% and 20%, respectively. Median overall survival (OS) was 35.5 months. The OS at 1, 2 and 5 years was 80%, 58% and 32%, respectively.

CONCLUSION

RFA is a safe and effective alternative treatment for the inoperable patients with primary or metastatic pulmonary malignant nodules. The clinical impact and long-term results of RFA need to be further confirmed in a larger series of patients, and RFA should ideally be compared with surgery.

Radiofrequency Ablation of Small Renal Masses

Although the incidence of localized renal cell carcinoma has increased in recent decades due to greater use of imaging, the treatment has shifted to less invasive, nephron-sparing approaches. Radiofrequency ablation (RFA) is one accepted treatment modality for patients with small renal masses, and it has the advantage of being minimally invasive and highly nephron sparing, with the additional benefits of reduced blood loss and complication rates. We describe our experience with RFA with an accompanying instructional video outlining the procedure's key components.

Long-Term Outcomes of Transarterial Chemoembolization Combined with Radiofrequency Ablation Versus Transarterial Chemoembolization Alone for Recurrent Hepatocellular Carcinoma After Surgical Resection

BACKGROUND

There is lack of data for identifying optimal local therapy for the management of recurrent hepatocellular carcinoma (HCC) after hepatic resection.

AIMS

A retrospective study was performed to compare the effectiveness of transarterial chemoembolization (TACE) plus radiofrequency ablation (RFA) with that of TACE alone for recurrent HCC.

METHODS

From 2007 to 2013, patients with recurrent HCC ≤ 5 cm were treated with either TACE plus RFA (n = 96) or TACE (n = 63). Inverse probability of treatment weighting was used to make allowances for imbalances in treatment assignment. The disease-free survival (DFS) and overall survival (OS) were retrospectively analyzed.

RESULTS

The TACE group had lower pretreatment Child-Pugh class (P = 0.025) and shorter pretreatment interval of recurrence (P = 0.028). The 1-, 3-, and 5-year DFS rates for the TACE-RFA group were 55.1%, 22.5%, and 9.7%, respectively, and 41.1%, 9.9%, and 4.9%, respectively, for the TACE group. The OS rates at 1, 3, and 5 years were 82.3%, 42.7%, and 16.5%, respectively, in the TACE-RFA group, and 75.9%, 30.7%, and 11.3%, respectively, in the TACE group. Cirrhosis was significantly associated with disease progression (hazard ratio [HR] 1.53; 95% CI 1.09-2.14; P = 0.014).

CONCLUSIONS

In patients with recurrent HCC ≤ 5 cm, TACE-RFA shows better DFS than TACE alone as a first-line local therapy.

Fully laparoscopic thermo-ablation of liver malignancies with or without liver resection: tumor location is an independent local recurrence risk factor

BACKGROUND

The aim of this study was to analyze risk factors of local recurrence (LR) after exclusive laparoscopic thermo-ablation (TA) with or without associated liver resection.

METHODS

Between 2012 and 2017, among 385 patients who underwent 820 TA in our department, 65 (17%) patients (HCC = 11, LM = 54) had exclusive laparoscopic TA representing 112 lesions (HCC = 17, LM = 95). TA was associated with other procedures in 57% of cases (liver resection 81%). All TA were done without liver clamping. Median tumor size was 1.8 cm [ranges from 0.3 to 4.5], 18% of the lesions were larger than 3 cm in size and 11% close to major liver vessels. Tumors locations were 77.5% in right liver, 36% in S7&S8, and 46% in S7&S8&S4a.

RESULTS

Mortality was nil and morbidity rate 15.4% including Dindo-Clavien > II grade 3%. The median follow-up was 24 months [0.77-75]. Per lesion LR rate after TA was 18% (n = 19 patients) with a mean time of 7.6 months. Among patients with LR, 18 (95%) could have been re-treated successfully (new resection = 11, re-TA = 7). Multivariate analyses revealed that tumor location in S7 alone, S7&S8 and/or S7, S8, or S4a were independent risk factors of LR after TA.

CONCLUSIONS

Exclusive laparoscopic TA is a safe and an effective tool to treat liver malignancies with or without liver resection. Other than classical risk factors, tumor location in upper segments of the liver, are independent risk factors for LR.

Oliguric acute kidney injury after microwave ablation of large liver tumors: incidence and preventive measures

PURPOSE

Acute kidney injury (AKI), especially oliguric AKI, is a recognized complication following microwave ablation (MWA) of large liver tumors. This study evaluated the clinical features, mechanisms, risk factors and prevention strategies for oliguric AKI after MWA of large liver tumors.

METHODS

From March 2011 to May 2015, 441 patients with liver tumors ≧5 cm received MWA in our hospital. The clinical features, prevention strategies, further mechanisms and possible risk factors for oliguric AKI after MWA were analyzed.

RESULTS

One hundred four (23.6%) patients had AKI after MWA; 11 (10.6%) patients had oliguric AKI, and 93 (89.4%) patients had nonoliguric AKI. All patients with nonoliguric AKI recovered without any special treatments. The eleven patients with oliguric AKI received appropriate treatments and had completely normal renal function three months later. Using double needles for ablation was a risk factor for nonoliguric AKI, while high preoperative levels of red blood cells (RBC), hemoglobin (HGB) and albumin (Alb) were risk factors for oliguric AKI. The decrease levels of hemoglobin were significantly high in oliguric AKI patients (p < .05). Patients with oliguric AKI had abnormally high postoperative transaminase and renal function indicators. Compared to postoperative prevention, intraoperative prevention significantly lowered the occurrence of oliguric AKI (0% vs. 3.7%, p = .018) and shortened the hospital stay.

CONCLUSIONS

Patients who underwent MWA for large liver tumors are prone to develop oliguric AKI. Implementation of intraoperative strategies during MWA can effectively prevent the occurrence of this severe complication.

Radiofrequency ablation combined with esophageal stent in the treatment of malignant esophageal stenosis: A single-center prospective study

The purpose of this study was to investigate the efficacy of radiofrequency ablation (RFA) combined with esophageal stent in treating malignant esophageal stenosis. Seventy patients with malignant esophageal obstruction treated in Department of Gastroenterology from April 2013 to April 2015 in China-Japan Union Hospital of Jilin University were enrolled. They were randomly assigned into the treatment group (radiofrequency ablation combined with esophageal stent) and control group (esophageal stent). To observe the degree of dysphagia, esophageal stenosis diameter, readmission time, adverse events and complications. There was no significant differences in dysphagia and esophageal diameter between the treatment group and the control group within 1–3 months after operation (P>0.05), and the degree of dysphagia and esophageal diameter in the treatment group at postoperative 6 months were better than those in the control group (P=0.018 and 0.038, respectively). The readmission time of the treatment group was also better than that of the control group (P=0.021). The adverse events and complications included hemorrhage, perforation and esophageal stent displacement. No significant differences in adverse events and complications between the treatment group and the control group were observed. All patients were successfully treated during hospitalization. Effect of radiofrequency ablation combined with esophageal stent implantation was better than esophageal stent implantation in the treatment of malignant esophageal stenosis, but it had no effect on the survival time.

Phase I/II Study of Radiofrequency Ablation for Painful Bone Metastases: Japan Interventional Radiology in Oncology Study Group 0208

PURPOSE

A prospective multicenter phase I/II trial was performed to evaluate the clinical safety and efficacy of radiofrequency ablation (RFA) for metastatic bone tumors.

MATERIALS AND METHODS

Thirty-three patients (27 men, 6 women, mean age 61 years) with metastatic bone tumors were enrolled. In phase I, nine patients were enrolled, and the safety of RFA was evaluated. In phase II, 23 patients were included, and an intent-to-treat analysis was performed. The primary endpoint was to evaluate the treatment's safety. The secondary endpoint was to evaluate the efficacy of pain relief at 1 week after RFA.

RESULTS

RFA was performed in 32 of 33 enrolled patients. No serious complications were observed during the phase I, so phase II was performed. Four patients exhibited adverse events, including one case each of Grade 3 pain and, Grade 2 hypotension, and one patient developed Grade 1 burns at the grounding pad and puncture site. One patient died of liver failure on day 7 after RFA due to the progression of the primary lesion. The efficacy was excellent (no increase in analgesic dosage, post-RFA VAS score of 0-2 or decreased by not less than 5 compared to before RFA) in 20 patients (60.6%), good (no increase in analgesic dosage, post-RFA VAS score decreased by not less than 2 but by < 5 compared to before RFA) in 3 (9.1%), and poor in 10 patients (30.3%). Thus, the response rate was 69.7%.

CONCLUSION

RFA is a safe and effective method for treating painful metastatic bone tumors.

A prospective randomized study comparing radiofrequency ablation and hepatic resection for hepatocellular carcinoma

Purpose

Although there are several prospective clinical studies comparing radiofrequency ablation (RFA) and hepatic resection (HR) for the treatment of hepatocellular carcinoma, there are few trials that have been performed in strictly homogeneous patients.

Methods

Patients who were newly diagnosed with a solitary hepatocellular carcinoma were randomized to the HR or RFA group. Inclusion criteria were as follows: age ≥ 20 years but ≤ 70 years, Child-Pugh class A, maximal diameter of the tumor ≥ 2 cm but ≤ 4 cm, no previous treatment history, and platelet count > 80,000/mm³.

Results

Although the study was early terminated, 29 and 34 patients were enrolled in the HR and RFA groups, respectively, and prospectively followed on an intention-to-treat basis. The 5-year overall survival rates were 83.4% and 86.2% in the HR and RFA groups, respectively, which were not significantly different (P = 0.812 by log-rank, P = 0.990 by Breslow). The 3- and 5-year disease-free survival rates in the HR group were significantly superior to those in the RFA group (66.7%, 44.4% vs. 44.1%, 31.2%, P = 0.071 by log-rank, P = 0.023 by Breslow). Intrahepatic local recurrence tended to develop more frequently in the RFA group (P = 0.042), while the frequency of intrahepatic distant and extrahepatic recurrence was similar bet ween the 2 groups. There were no significant differences in the frequency and severity of complications between the 2 groups.

Conclusion

HR was significantly superior to RFA in terms of disease-free survival; however, the overall survival was excellent in both groups.

Active contour configuration model for estimating the posterior ablative margin in image fusion of real-time ultrasound and 3D ultrasound or magnetic resonance images for radiofrequency ablation: an experimental study

Purpose

The purpose of this study was to evaluate the accuracy of an active contour model for estimating the posterior ablative margin in images obtained by the fusion of real-time ultrasonography (US) and 3-dimensional (3D) US or magnetic resonance (MR) images of an experimental tumor model for radiofrequency ablation.

Methods

Chickpeas (n=12) and bovine rump meat (n=12) were used as an experimental tumor model. Grayscale 3D US and T1-weighted MR images were pre-acquired for use as reference datasets. US and MR/3D US fusion was performed for one group (n=4), and US and 3D US fusion only (n=8) was performed for the other group. Half of the models in each group were completely ablated, while the other half were incompletely ablated. Hyperechoic ablation areas were extracted using an active contour model from real-time US images, and the posterior margin of the ablation zone was estimated from the anterior margin. After the experiments, the ablated pieces of bovine rump meat were cut along the electrode path and the cut planes were photographed. The US images with the estimated posterior margin were compared with the photographs and post-ablation MR images. The extracted contours of the ablation zones from 12 US fusion videos and post-ablation MR images were also matched.

Results

In the four models fused under real-time US with MR/3D US, compression from the transducer and the insertion of an electrode resulted in misregistration between the real-time US and MR images, making the estimation of the ablation zones less accurate than was achieved through fusion between real-time US and 3D US. Eight of the 12 post-ablation 3D US images were graded as good when compared with the sectioned specimens, and 10 of the 12 were graded as good in a comparison with nicotinamide adenine dinucleotide staining and histopathologic results.

Conclusion

Estimating the posterior ablative margin using an active contour model is a feasible way of predicting the ablation area, and US/3D US fusion was more accurate than US/MR fusion.

The Place of Elastography in Evaluating the Efficacy of Radiofrequency Ablation of Thyroid Nodules

The usage of radiofrequency ablation (RFA) therapy and elastography to treat thyroid nodules has been increasing recently. Elastography specifically measures the stiffness of tissue using ultra-sonography (US). The aim of the present study was to evaluate the relationship between the elastography values of thyroid nodules and the efficacy of RFA therapy. Ultrasonography was performed on 49 patients who had a thyroid nodule with a diameter of 1 cm or greater before RFA therapy. The RFA was performed under local anesthesia, and elastography was used to measure the stiffness of the normal thyroid tissue, sternocleidomastoid muscle (SCM) and thyroid nodules three months after RFA. The nodule diameter significantly decreased three months after RFA (P < 0.05). According to a cross-evaluation of the mean elastography rates, the thyroid/SCM and nodule/thyroid elastography rates had an inverse relationship (P: 0.009). However, the thyroid/ SCM elastography rates and nodule/SCM elastography rates (P: 0.022) and the thyroid/SCM elastography rates and the rates of reduction (%) of the nodule diameter before and three months after RFA (P: 0.016) had positive relationships. In conclusion, RFA therapy is more effective in patients with thyroid nodules if there are high thyroid tissue/SCM rates in elastography.

Model-based optimal planning of hepatic radiofrequency ablation

This article presents a model-based pre-treatment optimal planning framework for hepatic tumour radiofrequency (RF) ablation. Conventional hepatic radiofrequency (RF) ablation methods rely on pre-specified input voltage and treatment length based on the tumour size. Using these experimentally obtained pre-specified treatment parameters in RF ablation is not optimal to achieve the expected level of cell death and usually results in more healthy tissue damage than desired. In this study we present a pre-treatment planning framework that provides tools to control the levels of both the healthy tissue preservation and tumour cell death. Over the geometry of tumour and surrounding tissue, we formulate the RF ablation planning as a constrained optimization problem. With specific constraints over the temperature profile (TP) in pre-determined areas of the target geometry, we consider two different cost functions based on the history of the TP and Arrhenius index (AI) of the target location, respectively. We optimally compute the input voltage variation to minimize the damage to the healthy tissue while ensuring a complete cell death in the tumour and immediate area covering the tumour. As an example, we use a simulation of a 1D symmetric target geometry mimicking the application of single electrode RF probe. Results demonstrate that compared to the conventional methods both cost functions improve the healthy tissue preservation.

Interventional radiology in breast cancer

Molecular profiling of metastatic disease may greatly influence the systemic therapy recommended by oncologists and chosen by patients, allowing treatment to be more targeted. Comprehensive care of patients with advanced breast cancer now includes percutaneous image-guided biopsy if this has the potential to influence systemic treatment [1]. Interventional radiologists can contribute significantly to the care of patients affected by breast cancer, in diagnostic and supportive procedures and importantly also in treatment. Interventional radiologists carry out image guided percutaneous biopsies not only of the primary tumour but also of metastases. They insert percutaneous ports and tunnelled central venous catheters. They ablate painful bone metastases, and can treat or prevent pathological fractures. Most importantly they can ablate liver metastases in patients with limited or oligometastatic disease. The inhomogeneity and variety of cell populations in metastatic tumours from breast cancer, which is an important consideration in systemic therapy, is not an important consideration in the treatment of metastatic tumours using percutaneous ablative techniques, which are the major focus of this article. The treatment of primary tumours in the breast is also being explored, but is considered in its infancy at this stage.

Percutaneous Radiofrequency Ablation of Unresectable Locally Advanced Pancreatic Cancer: Preliminary Results

AIM

The objective of this study was to evaluate the efficacy of percutaneous radiofrequency ablation of locally advanced pancreatic cancer located in the pancreatic body.

MATERIALS AND METHODS

Patients with biopsy-proven locally advanced pancreatic adenocarcinoma were considered for percutaneous radiofrequency ablation. Postprocedural computed tomography studies and Ca19.9 tumor marker evaluation were performed at 24 hours and 1 month. At computed tomography, treatment effect was evaluated by excluding the presence of complications. The technical success of the procedure is defined at computed tomography as the achievement of tumoral ablated area.

RESULTS

Twenty-three patients have been included in the study. Five of the 23 patients were excluded. At computed tomography, the mean size of the intralesional postablation necrotic area was 32 mm (range: 15-65 mm). Technical success of the procedure has been obtained in 16 (93%) of the 18 cases. None of the patients developed postprocedural complications. Mean Ca19.9 serum levels 1 day before, 1 day after, and 1 month after the procedure were 285.8 U/mL (range: 16.6-942.0 U/mL), 635.2 U/mL (range: 17.9-3368.0 U/mL), and 336.0 U/mL (range: 7.0-1400.0 U/mL), respectively. Follow-up duration was less than 6 months for 11 patients and more than 6 months for 7 patients. At the time of the draft of this article, the mean survival of the patients included in the study was 185 days (range: 62-398 days).

CONCLUSION

Percutaneous radiofrequency ablation of locally advanced adenocarcinoma has a high technical success rate and is effective in cytoreduction both at imaging and laboratory controls.

Early assessment of coagulation necrosis after hepatic microwave ablation: a comparison of non-enhanced and enhanced T1-weighted images

PURPOSE

To compare the technical success and accuracy of hepatic microwave ablation (MWA) using non-enhanced and enhanced T1-weighted imaging early after ablation. Patients were evaluated with regard to the ablation zone and local tumor progression (LTP).

METHODS

This retrospective study conducted between September 2014 and December 2015 which consisted of 56 patients with 56 hepatic malignant lesions who underwent percutaneous MWA. Non-enhanced and contrast-enhanced T1-weighted imagings were performed within 2 days after tumor ablation. The efficacy of ablation assessed according to the hyperintense middle zone on non-enhanced T1-weighted images and the non-enhanced area on contrast-enhanced T1-weighted images were compared. The development of LTP during ≥7 months of follow-up served as the end point.

RESULTS

On the non-enhanced T1-weighted images, the ablated region had a characteristic two-zone structure featuring a hyperintense middle zone and a surrounding hypointense band. Among the 56 patients, LTP developed in ten including seven lesions, in which both the non-enhanced T1-weighted and portal-phase images showed incomplete tumor ablation. In two of the remaining three patients, incomplete tumor ablation was detected on the non-enhanced T1-weighted images, whereas the corresponding portal-phase images showed complete ablation. In the remaining patient, no residual tumor was detected on either the non-enhanced T1-weighted or the portal-phase images. In the 46 patients without LTP, there was no evidence of residual tumor on the non-enhanced T1-weighted or portal-phase images obtained early after ablation.

CONCLUSIONS

Non-enhanced T1-weighted images are useful in assessing the therapeutic efficacy of MWA of liver tumors early after the procedure.

Switching Monopolar Radiofrequency Ablation Using a Separable Cluster Electrode in Patients with Hepatocellular Carcinoma: A Prospective Study

OBJECTIVE

This study was conducted to evaluate the outcomes of multi-channel switching RFA using a separable cluster electrode in patients with HCC.

METHODS

From November 2011 to July 2013, 79 patients with 98 HCCs < 5 cm were enrolled and treated with RFA using a multi-channel switching radiofrequency system and a separable cluster electrode under the guidance of a real-time fusion imaging system. The primary and secondary endpoints were the 3-year local tumor progression (LTP) rate and recurrence-free survival (RFS) rate, respectively. For post hoc analyses, LTP, RFS, and major complication rates were retrospectively compared with a historical control group treated with RFA using the same radiofrequency system but with multiple internally-cooled electrodes.

RESULTS

The technique success rate of the 98 tumors was 100%. Cumulative 1-year, 2-year, and 3-year LTP rates were 3.4%, 6.9%, and 12.4%, respectively. For patient-level data, cumulative 1-year, 2-year, and 3-year RFS rates were 83.9%, 68.6%, and 45.4%, respectively. On post hoc analyses, none of the baseline characteristics showed a significant difference between the separable cluster electrode and multiple internally-cooled electrodes group. Cumulative LTP and RFS rates of the two groups also showed no significant difference (p = 0.401 and p = 0.881, respectively). Finally, major complication rates of the separable cluster electrode group (5.0%, 4/79) and multiple internally-cooled electrodes group (5.9%, 4/74) were also comparable (p = 1.000).

CONCLUSION

Switching monopolar RFA using a separable cluster electrode is a feasible and efficient technique for the treatment of HCCs smaller than 5 cm, providing comparable local tumor control to multiple internally-cooled electrodes.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02745483.

Angled Cool-Tip Electrode for Radiofrequency Ablation of Small Superficial Subcapsular Tumors in the Liver: A Feasibility Study

Objective

To evaluate the feasibility of angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular liver tumors abutting abdominal wall, in order to traverse normal liver parenchyma, and thereby, obtain favorable configuration of ablation margin.

Materials and Methods

In this study, we retrospectively analyzed 15 small superficial subcapsular liver tumors abutting abdominal wall in 15 patients, treated with radiofrequency ablation from March 2013 to June 2015 using a cool-tip electrode manually modified to create 25–35° angle at the junction between exposed and insulated segments. The tumors were hepatocellular carcinoma (n = 13) and metastases (n = 2: cholangiocellular carcinoma and rectosigmoid cancer), with maximum diameter of 10–26 mm (mean, 15.68 ± 5.29 mm). Under ultrasonographic guidance, the electrode tip was advanced to the depth of the tumors' epicenter about 1 cm from the margin. The tip was re-directed to penetrate the tumor for radiofrequency ablation. Minimal ablation margin was measured at immediate post-treatment CT. Radiological images and medical records were evaluated for success rate, length of minimal ablation margin and complications.

Results

Technical success rate of obtaining complete necrosis of the tumors was 100%, with no procedure-related complication. Minimal ablation margin ranged from 3–12 mm (mean, 7.07 ± 2.23 mm). CT/MRI follow-up at 21–1022 days (mean, 519.47 ± 304.51 days) revealed no local recurrence, but distant recurrence in 9 patients.

Conclusion

Using an angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular tumors abutting abdominal wall may be a feasible technique for obtaining adequate ablation margin and lower complication rate.

Efficacy of additional radiofrequency ablation after transcatheter arterial chemoembolization for intermediate hepatocellular carcinoma

AIM

For intermediate hepatocellular carcinoma (HCC), transcatheter arterial chemoembolization (TACE) therapy is recommended in the guidelines as a monotherapy, although TACE is a non-curative therapy. The aims of the present study were to evaluate the efficacy of adding radiofrequency ablation (RFA) to TACE in patients with intermediate HCC, and to identify the factors that were associated with favorable survival in these patients.

METHODS

Fifty-nine patients with intermediate HCC were enrolled in this retrospective study. Thirty-nine patients were treated with TACE alone and 20 patients were treated with additional RFA after TACE.

RESULTS

The recurrence-free survival rates at 0.5, 1 and 2 years for the additional RFA group were 32%, 19% and 13%, respectively, and these were significantly higher than those of the TACE group (8%, 3% and 0%, respectively; log-rank test, P = 0.001). The cumulative survival rates of the additional RFA group were significantly higher than those of the TACE group (log-rank test, P = 0.002), although this significant difference was not found in the subgroup of treatment naive patients because of small sample size. Multivariate analysis indicated male sex, lower total bilirubin, lower α-fetoprotein, lower des-γ-carboxyprothrombin, newly recurrent HCC nodules within the last 12 months and additional RFA as independent factors that were significantly associated with favorable overall survival.

CONCLUSION

Additional RFA of nodules insufficiently treated by TACE is effective therapy for obtaining favorable disease-free survival in patients with intermediate HCC, and leads to better overall survival particularly in recurrent patients.

Single-session radiofrequency ablation on benign thyroid nodules: a prospective single center study : Radiofrequency ablation on thyroid

PURPOSE

The activity of the application of single-session ultrasonography (US)-guided percutaneous radio frequency ablation (RFA) in benign thyroid nodules was investigated in this prospective clinical study.

METHODS

RFA treatment was applied to 100 nodules in 100 patients (78 women, 22 men; average age 44.5 years old; age range 18-71) who had euthyroid condition, nodule size larger than 1 cm in the ultrasonography, proven to be benign by fine needle aspiration cytology. The nodules were separated into three groups according to the content: solid, cystic and mixed. In first 73 cases, the process performed under local anesthesia and the other 27 cases were performed under general anesthesia. RFA process was standardized to 70 W in all of the patients, and a moving shot technique was used. The results acquired in the third and sixth months of the controls were evaluated, and the volume of the nodules was screened.

RESULTS

No differences between the thyroid function tests performed before and after RFA were detected (p > 0.05). The mean volume of the nodules before the process, in the third month after the process, and in the sixth month were 16.8, 4.8, and 2.6 ml, respectively (p < 0.001). The decrease in cystic nodules was greater than solid and mixed structures. Temporary hoarseness occurred in one case and skin edema was detected in a patient at the isthmus.

CONCLUSIONS

RFA is an option for treatment, with minimal invasiveness and a low complication rate, and it is effective primarily in cases with benign nodules and nodular goiter. In cases with good compliance, the likelihood of success is greater. General anesthesia can be a good option for anxious cases to gather better results.

Radiofrequency Ablation with an Internally Cooled Electrode for Twin Reversed Arterial Perfusion Sequence

OBJECTIVE

The study aims to evaluate the efficacy of radiofrequency ablation (RFA) with an internally cooled electrode for twin reversed arterial perfusion (TRAP) sequence.

METHODS

From April 2008 through December 2014, we retrospectively reviewed all patients who underwent RFA with an internally cooled electrode for TRAP sequence at 3 tertiary referral centers in Japan.

RESULTS

Twenty-five monochorionic diamniotic twin pregnancies underwent RFA with an internally cooled electrode for TRAP sequence at 16-27 weeks of gestation. In all cases, umbilical cord blood flow cessation in the acardiac twin was confirmed by ultrasonography with color Doppler. There were 2 cases of procedure-related complications: 1 case of unintentional septostomy and 1 case of anemia in a pump twin. Fetal demise of the pump twin occurred in 3 (12%) cases. Twenty-two (88%) of 25 pump twins were delivered alive. The median gestational age at delivery was 36 + 3 weeks (range 25 + 2-40 + 5 weeks). There were 14 cases (64%) of premature deliveries before 37 weeks and 5 (23%) before 32 weeks.

CONCLUSION

RFA with an internally cooled electrode is a feasible and effective procedure for the treatment of TRAP sequence.

CT Appearance of Hepatocellular Carcinoma after Locoregional Treatments: A Comprehensive Review

Hepatocellular carcinoma (HCC) is a major health problem worldwide, affecting more than 600,000 new patients per year. Curative treatments are available in a small percentage of patients, while most of them present in stages requiring locoregional treatments such as thermoablation, transarterial chemoembolization, and/or radioembolization. These therapies result in specific imaging features that the general radiologist has to be aware of in order to assess the response to treatment and to correctly manage the follow-up of treated patients. Multiphasic helical computed tomography has become a popular imaging modality for detecting hypervascular tumors and characterizing liver lesions. On this basis, many staging and diagnostic systems have been proposed for evaluating response to all different existing strategies. Radiofrequencies and microwaves generate thermoablation of tumors, and transarterial chemoembolization exploits the double effect of the locoregional administration of drugs and embolizing particles. Eventually radioembolization uses a beta-emitting isotope to induce necrosis. Therefore, the aim of this comprehensive review is to analyze and compare CT imaging appearance of HCC after various locoregional treatments, with regard to specific indications for all possible procedures.

Cryoablation Versus Radiofrequency Ablation for Hepatic Malignancies: A Systematic Review and Literature-Based Analysis

The aim of this study is to summarize and quantify the current evidence on the therapeutic efficacy of cryoablation compared with radiofrequency ablation (RFA) in patients with hepatic malignancies in a meta-analysis.Data were collected by searching PubMed, Scopus, and Cochrane databases for reports published up to May 26, 2015. Studies that reported data on comparisons of therapeutic efficacy of cryoablation and RFA were included. The random effects model was used to estimate the pooled relative risks of events comparing cryoablation to RFA for therapy of hepatic malignancies.Seven articles met the inclusion criteria and were included in the meta-analysis. The meta-analysis showed that there was no statistically significant difference in mortality of at least 6 months (odds ratio [OR] = 1.00, 95% confidence interval [CI]: 0.68-1.49) and local tumor progression according to both patients (OR = 1.64, 95% CI: 0.57-4.74) and tumors (OR = 1.81, 95% CI: 0.74-4.38) between cryoablation group and RFA group. However, the risk of complications was significantly higher in the cryoablation group than that in the RFA group (OR = 2.93, 95% CI: 1.15-7.46). When considering the specific complications, only thrombocytopenia (OR = 51.13, 95% CI: 2.92-894.21) and renal impairment (OR = 4.19, 95% CI: 1.34-13.11) but not other complications were significantly higher in the cryoablation group.In conclusion, the 2 methods had almost equal mortality and nonsignificant difference in local tumor progression, with higher risk of complications in cryoablation. Further large-scale, well-designed randomized controlled trials are needed to identify the current findings and investigate the long-term effects of cryoablation compared with RFA for therapy of hepatic malignancies.

Hepatic radiofrequency ablation: in vivo and ex vivo comparisons of 15-gauge (G) and 17-G internally cooled electrodes

OBJECTIVE

To compare the performance of the 15-G internally cooled electrode with that of the conventional 17-G internally cooled electrode.

METHODS

A total of 40 (20 for each electrode) and 20 ablation zones (10 for each electrode) were made in extracted bovine livers and in in vivo porcine livers, respectively. Technical parameters, three dimensions [long-axis diameter (Dl), vertical-axis diameter (Dv) and short-axis diameter (Ds)], volume and the circularity (Ds/Dl) of the ablation zone were compared.

RESULTS

The total delivered energy was higher in the 15-G group than in the 17-G group in both ex vivo and in vivo studies (8.78 ± 1.06 vs 7.70 ± 0.98 kcal, p = 0.033; 11.20 ± 1.13 vs 8.49 ± 0.35 kcal, p = 0.001, respectively). The three dimensions of the ablation zone had a tendency to be larger in the 15-G group than in the 17-G group in both studies. The ablation volume was larger in the 15-G group than in the 17-G group in both ex vivo and in vivo studies (29.61 ± 7.10 vs 23.86 ± 3.82 cm(3), p = 0.015; 10.26 ± 2.28 vs 7.79 ± 1.68 cm(3), p = 0.028, respectively). The circularity of ablation zone was not significantly different in both the studies.

CONCLUSION

The size of ablation zone was larger in the 15-G internally cooled electrode than in the 17-G electrode in both ex vivo and in vivo studies.

ADVANCES IN KNOWLEDGE

Radiofrequency ablation of hepatic tumours using 15-G electrode is useful to create larger ablation zones.

Evaluation of a thermoprotective gel for hydrodissection during percutaneous microwave ablation: in vivo results

PURPOSE

To evaluate whether thermoreversible poloxamer 407 15.4 % in water (P407) can protect non-target tissues adjacent to microwave (MW) ablation zones in a porcine model.

MATERIALS AND METHODS

MW ablation antennas were placed percutaneously into peripheral liver, spleen, or kidney (target tissues) under US and CT guidance in five swine such that the expected ablation zones would extend into adjacent diaphragm, body wall, or bowel (non-target tissues). For experimental ablations, P407 (a hydrogel that transitions from liquid at room temperature to semi-solid at body temperature) was injected into the potential space between target and non-target tissues, and the presence of a gel barrier was verified on CT. No barrier was used for controls. MW ablation was performed at 65 W for 5 min. Thermal damage to target and non-target tissues was evaluated at dissection.

RESULTS

Antennas were placed 7 ± 3 mm from the organ surface for both control and gel-protected ablations (p = 0.95). The volume of gel deployed was 49 ± 27 mL, resulting in a barrier thickness of 0.8 ± 0.5 cm. Ablations extended into non-target tissues in 12/14 control ablations (mean surface area = 3.8 cm(2)) but only 4/14 gel-protected ablations (mean surface area = 0.2 cm(2); p = 0.0005). The gel barrier remained stable at the injection site throughout power delivery.

CONCLUSION

When used as a hydrodissection material, P407 protected non-targeted tissues and was successfully maintained at the injection site for the duration of power application. Continued investigations to aid clinical translation appear warranted.

Transcatheter arterial chemoembolization for hepatocellular carcinoma: Comparison of the therapeutic efficacies between miriplatin and epirubicin

AIM

The therapeutic efficacy of transcatheter arterial chemoembolization (TACE) using miriplatin was evaluated in comparison with that using epirubicin in patients with hepatocellular carcinoma (HCC).

METHODS

Two hundred and eight-nine HCC patients receiving TACE were retrospectively enrolled; none of the patients gave a previous TACE history. The short-term therapeutic efficacy was evaluated by computed tomography (CT) performed 1 month later. In patients showing TE-4, CT and/or magnetic resonance imaging examinations were performed repeatedly and the long-term therapeutic efficacy was assessed based on local tumor recurrence.

RESULTS

After exclusion of 68 patients (CT not performed at 1 month), 97 patients treated with epirubicin and 124 treated with miriplatin were analyzed. The percentage of patients showing TE-4 was 46.8% in the miriplatin-TACE group, being significantly higher than that in the epirubicin-TACE group (33.0%). The cumulative local recurrence rates at 18 months were 71.2% in the miriplatin-TACE group and 43.1% in the epirubicin-TACE group; multivariate analysis revealed higher local tumor recurrence rates in the miriplatin-TACE group than in the epirubicin-TACE group.

CONCLUSION

For HCC patients, although miriplatin-TACE was superior to epirubicin-TACE in the short term, it proved inferior to the latter in the long term. The merits of TACE using miriplatin should be further investigated, because adverse effects appear to be minimal after miriplatin administration.

Combining locoregional therapies in the treatment of hepatocellular carcinoma

In an effort to promote more durable local control of larger lesions, thermal ablation has been combined with chemical ablative techniques and with vaso-occlusive procedures such as chemoembolization and bland embolization in an effort to mitigate the limitations inherent in the use of any single treatment for hepatocellular carcinoma (HCC) >3 cm. The heat-sink effect is the underlying principle for combining vaso-occlusive therapies with ablative techniques. Combination therapies do present viable options for abrogating tumor progression and potentially downsizing tumors to facilitate transplant. We discuss the two most commonly used combination locoregional therapies by the interventionalist and the evidence defining the best techniques in practice.

Cancer-free survival and local tumor control after impendence-based radiofrequency ablation of biopsy-proven renal cell carcinomas with a minimum of 1-year follow-up

OBJECTIVES

There are numerous reports describing the use of radiofrequency ablation (RFA) to treat renal cell carcinoma. Many series, however, describe heterogeneous populations, lack histologic descriptions, use various RFA systems, and indicate tumor destruction by different ablation end points. This study examined the outcomes of computed tomography-guided, impedance-based RFA of biopsy-proven renal cell carcinoma clinically staged as T1a with a minimum of 1 year of postablation follow-up.

METHODS AND MATERIALS

This retrospective study identified all consecutive patients who had undergone renal RFA since May 2005 at our institution. Patients without biopsy-proven renal cell carcinoma (RCCa) were excluded. Of the patients who met these criteria, evaluation was limited to patients with a minimum of 12 months of follow-up. Data collected from the patients' electronic medical and radiologic records included demographic data, tumor-related data, procedural details, and clinical follow-up visits.

RESULTS

A total of 39 patients (46 lesions) met the inclusion criteria. The mean tumor diameter was 2.6 cm (range: 1.2-4.0 cm). The most common histologies were clear cell (n = 27) and papillary (n = 16) renal cancer. The lesion location was equally divided between upper pole (n = 16), middle pole (n = 16), and lower pole (n = 14). Overall, 83% of the tumors were exophytic. No residual or recurrent enhancing mass was identified in the ablation bed on post-RFA imaging during the mean follow-up period of 35.3 months (range: 12-83). All patients were treated in a single encounter and no lesion required a second ablation; technical success (absence of residual tumor) on the initial post-RFA imaging study was 46 of 46 (100%). Clinical success was achieved in 45 of 46 lesions (98%); residual, viable tumor was found in a pretransplant nephrectomy specimen on postprocedure day 127. The mean cancer-free survival was 36.2 months. Comparison of preablation and postablation renal function found no statistically significant change.

CONCLUSIONS

The consistent outcomes in our post-RFA imaging and clinical surveillance allow us to offer image-guided ablation to patients with T1a RCCa as a valid treatment option offering long-term cancer-free survival. Impedance-based RFA in a carefully selected patient population with T1a RCCa is a reliable treatment option, with disease-free survival rates that are comparable to partial nephrectomy.

Heat Sink Phenomenon of Bipolar and Monopolar Radiofrequency Ablation Observed Using Polypropylene Tubes for Vessel Simulation

Background. Radiofrequency ablation (RFA) is widely used for treating liver tumors; recurrence is common owing to proximity to blood vessels possibly due to the heat sink effect. We seek to investigate this phenomenon using unipolar and bipolar RFA on an egg white tumor tissue model and an animal liver model. Materials and methods. Temperature profiles during ablation (with and without vessel simulation) were studied, using both bipolar and unipolar RFA probes by 4 strategically placed temperature leads to monitor temperature profile during ablation. The volume of ablated tissue was also measured. Results. The volume ablated during vessel simulation confirmed the impact of the heat sink phenomenon. The heat sink effect of unipolar RFA was greater compared with bipolar RFA (ratio of volume affected 2:1) in both tissue and liver models. The volume ablated using unipolar RFA was less than the bipolar RFA (ratio of volume ablated = 1:4). Unipolar RFA achieved higher ablation temperatures (122°C vs 98°C). Unipolar RFA resulted in tissue damage beyond the vessel, which was not observed using bipolar RFA. Conclusion. Bipolar RFA ablates a larger tumor volume compared with unipolar RFA, with a single ablation. The impact of heat sink phenomenon in tumor ablation is less so with bipolar than unipolar RFA with sparing of adjacent vessel damage.

Multidisciplinary management of hepatocellular carcinoma in clinical practice

Background. Hepatocellular carcinoma (HCC) patients require different treatment strategies according to disease extension, liver function, and patient's fitness. We evaluated HCC multidisciplinary management in clinical practice. Methods. Consecutive patients were followed and treated with tailored medical, locoregional, and surgical treatments, according to disease stage and patient's fitness (age, Cumulative Illness Rating Scale (CIRS)). Activity, efficacy, and safety were evaluated. Results. Thirty-eight patients were evaluated: median age, 74; elderly 92%; CIRS secondary 28 (74%); Child-Pugh A 20 (53%), B 11 (29%); and Barcelona Clinic Liver Cancer (BCLC) 0 2 (5%), A 9 (24%), B 10 (26%), C 13 (34%), and D 4 (11%). Overall survival (OS) was 30 months. At 9 months median follow-up, among 25 unresectable HCC, OS was 10 months; BCLC B–D unfit for sorafenib showed OS 3 months. Ten patients (40%) received sorafenib: Child-Pugh A 5 (50%) and B 5 (50%) and disease control rate 89%, progression-free survival 7 months, and OS 9 months. G3-4 toxicities: anorexia, hypertransaminaemia, hyperbilirubinemia, and hypercreatininemia. Limiting toxicity syndromes were 40%, all multiple sites. Conclusion. HCC patients require multidisciplinary clinical management to properly select tailored treatments according to disease stage, fitness, and liver function. Patients suitable for sorafenib should be carefully selected, monitored for individual safety, and prevalently characterized by limiting toxicity syndromes multiple sites.

Evaluation of the current radiofrequency ablation systems using axiomatic design theory

This article evaluates current radiofrequency ablation systems using axiomatic design theory. Due to its minimally invasive procedure, short-time hospital stay, low cost, and tumour metastasis treatment, the radiofrequency ablation technique has been playing an important role in tumour treatment in recent decades. Although the radiofrequency ablation technique has many advantages, some issues still need to be addressed. Among these issues, the two most important are as follows: (1) the size of tumours to be removed (has to be larger than 3 cm in diameter) and (2) cleanness of the removal. Many device solutions have been proposed to address the two issues. However, there is a lack of knowledge regarding the systematic evaluation of these solutions. This article evaluates these systems in terms of their solution principles (or simply called conceptual design in general product design theory) using a design theory called axiomatic design theory. In addition, with the axiomatic design theory, a better conceptual design in terms of its feasibility to cope with incomplete target tissue necrosis from the large size of tumours has been found. The detailed analysis and simulation of the new conceptual design are conducted using finite element approach. The results in this article are proved by the information of animal experiments and clinical practices obtained from the literature. This study thus contributes to the current knowledge to further developments in radiofrequency ablation systems and procedure guidelines for physicians to perform the radiofrequency ablation operation more effectively.

The contemporary role of ablative treatment approaches in the management of renal cell carcinoma (RCC): focus on radiofrequency ablation (RFA), high-intensity focused ultrasound (HIFU), and cryoablation

INTRODUCTION

Currently, most of renal tumors are small, low grade, with a slow growth rate, a low metastatic potential, and with up to 30 % of these tumors being benign on the final pathology. Moreover, they are often diagnosed in elderly patients with preexisting medical comorbidities in whom the underlying medical conditions may pose a greater risk of death than the small renal mass. Concerns regarding overdiagnosis and overtreatment of patients with indolent small renal tumors have led to an increasing interest in minimally invasive, ablative as an alternative to extirpative interventions for selected patients.

OBJECTIVE

To provide an overview about the state of the art in radiofrequency ablation (RFA), high-intensity focused ultrasound, and cryoablation in the clinical management of renal cell carcinoma.

METHODS

A PubMed wide the literature search of was conducted.

RESULTS

International consensus panels recommend ablative techniques in patients who are unfit for surgery, who are not considered candidates for or elect against elective surveillance, and who have small renal masses. The most often used techniques are cryoablation and RFA. These ablative techniques offer potentially curative outcomes while conferring several advantages over extirpative surgery, including improved patient procedural tolerance, faster recovery, preservation of renal function, and reduction in the risk of intraoperative and postsurgical complications. While it is likely that outcomes associated with ablative modalities will improve with further advances in technology, their application will expand to more elective indications as longer-term efficacy data become available.

CONCLUSION

Ablative techniques pose a valid treatment option in selected patients.

Anti-viral therapy to reduce recurrence and improve survival in hepatitis B virus-related hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common malignancy and the third leading cause of cancer death worldwide. Chronic infection with hepatitis B virus (HBV) and hepatitis C virus accounts for approximately 75%-80% of HCC cases worldwide. In particular, chronic HBV infection is a predominant risk factor for HCC in Asia and Africa. Hepatic resection and radiofrequency ablation are increasingly used for the curative treatment of HCC, and good local control can be achieved. However, the high rate of recurrence is a major obstacle to improving prognosis. A high viral load of HBV DNA is the most important correctable risk factor for recurrence. Furthermore, interferon and/or nucleotide analogues may decrease HBV DNA. Therefore, these drugs may decrease recurrence. In this article, treatment strategies for HBV-related HCC are described in order to reduce recurrence and improve survival.

Radiofrequency (thermal) ablation versus no intervention or other interventions for hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma is the fifth most common cancer worldwide. Percutaneous interventional therapies, such as radiofrequency (thermal) ablation (RFA), have been developed for early hepatocellular carcinoma. RFA competes with other interventional techniques such as percutaneous ethanol injection, surgical resection, and liver transplantation. The potential benefits and harms of RFA compared with placebo, no intervention, chemotherapy, hepatic resection, liver transplantation, or other interventions are unclear.

OBJECTIVES

To assess the beneficial and harmful effects of RFA versus placebo, no intervention, or any other therapeutic approach in patients with hepatocellular carcinoma.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and ISI Web of Science to September 2012. We handsearched meeting abstracts from ASCO, ESMO, AASLD, EASL, APASL, and references of articles. We also contacted researchers in the field (last search September 2012).

SELECTION CRITERIA

We considered for inclusion randomised clinical trials investigating the effects of RFA versus placebo, no intervention, or any other therapeutic approach on hepatocellular carcinoma patients regardless of blinding, language, and publication status.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed the selection of trials, assessment of risk of bias, and data extraction. We contacted principal investigators for missing information. We analysed hazard ratios (HR) as relevant effect measures for overall survival, two-year survival, event-free survival, and local recurrences with 95% confidence intervals (CI). In addition, we analysed dichotomous survival outcomes using risk ratios (RR). We used trial sequential analysis to control the risk of random errors ('play of chance').

MAIN RESULTS

We identified no trials comparing RFA versus placebo, no intervention, or liver transplantation. We identified and included 11 randomised clinical trials with 1819 participants that included four comparisons: RFA versus hepatic resection (three trials, 578 participants); RFA versus percutaneous ethanol injection (six trials, 1088 participants) including one three-armed trial that also investigated RFA versus acetic acid injection; RFA versus microwave ablation (one trial, 72 participants); and RFA versus laser ablation (one trial, 81 participants). Ten of the eleven included trials reported on the primary outcome of this review, overall survival. Rates of major complications or procedure-related deaths were reported in 10 trials. The overall risk of bias was considered low in five trials and high in six trials. For a subgroup analysis, we included only low risk of bias trials. Regarding the comparison RFA versus hepatic resection, there was moderate-quality evidence from two low risk of bias trials that hepatic resection seems more effective than RFA regarding overall survival (HR 0.56; 95% CI 0.40 to 0.78) and two-year survival (HR 0.38; 95% CI 0.17 to 0.84). However, if we included a third trial with high risk of bias, the difference became insignificant (overall survival: HR 0.71; 95% CI 0.44 to 1.15). With regards to the outcomes event-free survival and local progression, hepatic resection also yielded better results than RFA. However, the number of complications was higher in surgically treated participants (odds ratio (OR) 8.24; 95% CI 2.12 to 31.95). RFA seemed superior to percutaneous ethanol or acetic acid injection regarding overall survival (HR 1.64; 95% CI 1.31 to 2.07). The RR for mortality was also in favour of RFA, but did not reach statistical significance (150/490 (30.6%) people in the percutaneous ethanol or acetic acid group versus 119/496 (24.0%) people in the RFA group; RR 1.76; 95% CI 0.97 to 3.22). The proportion of adverse events did not differ significantly between RFA and percutaneous ethanol or acetic acid injection (HR 0.70; 95% CI 0.33 to 1.48). Trial sequential analyses revealed that the number of participants in the included trials was insufficient and that more trials are needed to assess the effects of RFA versus other interventions.

AUTHORS' CONCLUSIONS

The effects of RFA versus no intervention, chemotherapeutic treatment, or liver transplantation are unknown. We found moderate-quality evidence that hepatic resection is superior to RFA regarding survival. However, RFA might be associated with fewer complications and a shorter hospital stay than hepatic resection. We found moderate-quality evidence showing that RFA seems superior to percutaneous ethanol injection regarding survival. There were too sparse data to recommend or refute ablation achieved by techniques other than RFA. More randomised clinical trials with low risk of bias and low risks of random errors assessing the effect of RFA are needed.

Citation classics in radiology journals: the 100 top-cited articles, 1945-2012

OBJECTIVE

The number of citations an article receives after its publication reflects its impact in the scientific community. The aim of this study was to identify and characterize the 100 top-cited articles published in radiology journals.

MATERIALS AND METHODS

The top-cited articles published in 12 radiology journals were identified using the database of Science Citation Index Expanded (1945-2012). The 100 top-cited articles were selected and analyzed with regard to the number of citations, year of publication, publishing journal, authorship, institution and country of origin, type of article, radiologic subspecialty, main topic, and radiologic technique.

RESULTS

The 100 top-cited articles were published in eight radiology journals, led by Radiology (n=67) and followed by the American Journal of Roentgenology (n=11). These articles were published between 1939 and 2006 with a mean of 664.3 citations per article (range, 371-6931). Seventy-eight articles were published after 1979, 57 originated from the United States, and 69 were original articles. The most common subspecialties of study were interventional radiology (n=19), neuroradiology (n=15), and breast imaging (n=11). The main topics of articles were radiofrequency ablation of hepatic tumors (n=9), followed by receiver operating characteristic curves (n=6).

CONCLUSION

Our study presents a detailed list and analysis of the 100 top-cited articles published in radiology journals, which provides insight into historical developments in the field of radiology.

Radiofrequency ablation technique in the treatment of liver tumours: review and future issues

Thermal ablation is increasingly being used for treatment of liver tumours. Among the techniques of thermal ablation, radiofrequency ablation (RF) is undoubtedly being used most frequently because of its advantages, such as morbidity and mortality rates, effective tumour ablation, as well as being less time-consuming. This paper presents the state of the art of RF ablation technique. This includes the theoretical development, experimental study and clinical application of the radiofrequency ablation technique. First, it introduces the principle of this technique. Second, it shows the development of this technique and valuable achievements. These achievements include the device, strategy of operation and extension to other diseases. Third, it concludes future issues to be addressed in order to further advance this technique.

Intraoperative ablation for small HCC not amenable for percutaneous radiofrequency ablation in Child A cirrhotic patients

BACKGROUND

Radiofrequency ablation (RFA) was initially started by radiologists as a percutaneous treatment, but surgeons started to use RFA by surgical approach for patients with tumors at locations difficult for the percutaneous procedure. The aim was to evaluate the results of intraoperative RFA for small hepatocellular carcinomas (HCCs) (<3 cm) in locations difficult for a percutaneous approach.

METHODS

Two hundred forty-seven patients with small solitary HCC (<3 cm) were treated; 196 via percutaneous RFA while 51 patients presented at sites not amenable for percutaneous route. Twenty-seven out of 51 patients underwent surgical resection, while 24/51 patients underwent intraoperative RFA.

RESULTS

The location and depth of the tumor from the liver capsule was the only significant factors in the choice of the surgeon between resection and RFA. RFA was successful in all tumors (complete ablation rate of 100 %). In the surgery group, all patients achieved R0 resection. Complication rate was comparable (p = 1.0). After a median follow-up of 37 months (range, 10-45 months), no tumors showed neither local progression nor local recurrence and no significant difference was observed between two groups as regards early recurrence and number of de novo lesions (p = 0.49). One-year and 3-year survival rates were 93 % and 81 %, respectively, in the resection group comparable to the corresponding rates of 92 % and 74 % in the RFA group (p = 0.9).

CONCLUSION

For small HCC in locations difficult for a percutaneous approach, intraoperative RFA can be an alternative option for deep-seated tumors necessitating more than one segmentectomy achieving similar tumor control, and overall and disease-free survival.

Evaluation of the in vivo efficiency and safety of hepatic radiofrequency ablation using a 15-G Octopus® in pig liver

OBJECTIVE

To determine in vivo efficacy of radiofrequency ablation (RFA) in porcine liver by using 15-gauge Octopus® (15-G Octopus®) electrodes to create a large coagulation.

MATERIALS AND METHODS

A total of 18 coagulations were created by using a 180-W generator and 15-G Octopus® electrodes during laparotomy, performed in 14 pigs. Coagulation necrosis was created in the pig livers by the use of one of three RFA protocols: 1) group A, monopolar RFA using a 15-G Octopus® electrode with a 5-mm inter-electrode distance (n = 4); 2) group B, monopolar RFA using a 15-G Octopus® electrode with a 10-mm inter-electrode distance (n = 6); and 3) group C, switching monopolar RFA using two 15-G Octopus® electrodes (n = 8). The energy efficiency, shape, maximum and minimum diameters (Dmx and Dmi), and the volume of the coagulation volume were measured in each group. The Summary statistics were obtained and Mann-Whitney test was were performed.

RESULTS

The mean ablated volume of each group was 49.23 cm(3) in A, 64.11 cm(3) in B, and 72.35 cm(3) in C. The mean Dmx and Dmi values were 5.68 cm and 4.58 cm in A and 5.97 cm and 4.97 cm in B, respectively. In group C, the mean diameters of Dmx and Dmi were 6.80 cm and 5.11 cm, respectively. The mean ratios of Dmi/Dmx were 1.25, 1.20, and 1.35 in groups A, B, and C, respectively. There was one animal death during the RFA procedure, the cause of which could not be subsequently determined. However, there were no other significant, procedure-related complications during the seven-hour-delayed CT scans.

CONCLUSION

RFA procedures using 15-G Octopus® electrodes are useful and safe for creating a large ablation in a single electrode model as well as in the multiple electrodes model.

Comparison of FDG-PET, MRI and CT for post radiofrequency ablation evaluation of hepatic tumors

PURPOSE

Treatment effect of radiofrequency ablation (RFA) is traditionally accomplished with MRI and/or CT. The aim of the study was to assess the role of FDG-PET in post RFA hepatic tumor evaluation, in comparison with MRI and CT.

MATERIALS AND METHODS

28 patients (33 hepatic RFA lesions) who had post RFA FDG-PET within 8 weeks of abdominopelvic MRI or CT were retrospectively reviewed. Accuracy of FDG-PET on post hepatic RFA evaluation was compared with MRI and/or CT based on clinical and imaging follow-up.

RESULTS

Among total of 33 RFA-treated lesions, 17 had residual or recurrent tumor (positive). PET identified 16 with a sensitivity of 94.1 %. Of these 17 lesions, 12 had concurrent MRI and 8 were positive with a sensitivity of 66.7 %. Similarly, 6 out of the 17 lesions had CT and 4 were positive with a sensitivity of 66.7 %. Sixteen lesions were successfully ablated (negative). Among them FDG-PET was negative in 13 with a specificity of 81.3 %; MRI was performed in 8 and 7 were negative with a specificity of 87.5 %; CT was performed in 8 and 5 were negative with a specificity of 62.5 %. The overall accuracy of PET, MRI and CT was 87.9, 75.0, and 64.3 %, respectively. The average scan numbers for PET, MRI and CT to achieve a final accurate diagnosis were 1.121, 1.316 and 1.250, with a corresponding cost of $1455.2, $1845.8, and $933.8, respectively.

CONCLUSIONS

The study suggests that FDG-PET is superior to MRI and/or CT and is more cost-effective in post RFA hepatic tumor assessment.

Endoscopic Ultrasound-Guided Radiofrequency Ablation (EUS-RFA) of the Pancreas in a Porcine Model

Backgrounds. Limited effective palliative treatments exist for pancreatic cancer which includes surgery or chemotherapy. Radiofrequency ablation (RFA) uses high frequency alternating current to ablate diseased tissue and has been used to treat various tumors. In this study, we evaluated a prototype probe adjusted to the EUS-needle to perform EUS-RFA to permit coagulative necrosis in the pancreas. Methods. Five Yucatan pigs underwent EUS-guided radiofrequency ablation of the head of their pancreas. Using an EUS-needle, RFA was applied with 6 mm and then 10 mm of the probe exposed at specific wattage for preset durations. Results. Only one pig showed moderate levels of pancreatitis (20% proximal pancreatitis). The other animals showed much lower areas of tissue damage. In 3 of the 5 pigs, the proximal pancreas showed greater levels of tissue injury than the distal pancreas, consistent with the proximity of the tissue to the procedure site. In 1 pig, both proximal and distal pancreas showed minimal pancreatitis (1%). There was minimal evidence of fat necrosis in intra-pancreatic and/or extra-pancreatic adipose tissue. Conclusion. EUS-guided RFA of the pancreatic head with the monopolar probe through a 19-gauge needle was well tolerated in 5 Yucatan pigs and with minimal amount of pancreatitis.

Long-term oncologic outcomes after radiofrequency ablation for T1 renal cell carcinoma

BACKGROUND

Radiofrequency ablation (RFA) of renal cell carcinoma (RCC) is used to obtain local control of small renal masses. However, available long-term oncologic outcomes for RFA of RCC are limited by small numbers, short follow-up, and lack of pathologic diagnoses.

OBJECTIVE

To assess the oncologic effectiveness of RFA for the treatment of biopsy-proven RCC.

DESIGN, SETTING, AND PARTICIPANTS

Exclusion criteria included prior RCC or metastatic RCC, familial syndromes, or T2 RCC. We retrospectively reviewed long-term oncologic outcomes for 185 patients with sporadic T1 RCC. Median follow-up was 6.43 yr (interquartile range [IQR]: 5.3-7.7).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The chi-square test and Wilcoxon rank-sum tests were used to compare proportions and medians, respectively. Disease-specific survival and overall survival (OS) were calculated using Kaplan-Meier analysis, then stratified by tumor stage, and comparisons were made using log-rank analysis. The 5-yr disease-free survival (DFS) and OS rates are reported. A p value <0.05 was considered statistically significant.

RESULTS AND LIMITATIONS

Median tumor size was 3 cm (IQR: 2.1-3.9 cm). Tumor stage was T1a: 143 (77.3%) or T1b: 42 (22.7%). Twenty-four patients (13%) were retreated for residual disease. There were 12 local recurrences (6.5%), 6 recurrences in T1a disease (4.2%) and 6 in T1b disease (14.3%) (p=0.0196). Median time to recurrence was 2.5 yr. Local salvage RFA was performed in six patients, of whom five remain disease free at 3.8-yr median follow-up. Tumor stage was the only significant predictor of DFS on multivariate analysis. At last follow-up, 164 patients (88.6%) were disease free (T1a: n=132 [92.3%]; T1b: n=32 [76.2%]; p=0.0038). OS was similar regardless of stage (p=0.06). Five patients developed metachronous renal tumors (2.7%). Four patients developed extrarenal metastases (2.2%), three of whom died of metastatic RCC (1.6%).

CONCLUSIONS

In poor surgical candidates, RFA results in durable local control and low risk of recurrence in T1a RCC. Higher stage correlates with a decreased disease-free survival. Long-term surveillance is necessary following RFA. Patient selection based on tumor characteristics, comorbid disease, and life expectancy is of paramount importance.