Radiofrequency Ablation for Viable Hepatocellular Carcinoma around Retained Iodized Oil after Transcatheter Arterial Chemoembolization: Usefulness of Biplane Fluoroscopy Plus Ultrasound Guidance

Objective

To assess the technical feasibility and local efficacy of biplane fluoroscopy plus US-guided percutaneous radiofrequency ablation (RFA) for viable hepatocellular carcinoma (HCC) around retained iodized oil after transcatheter arterial chemoembolization (TACE).

Materials and Methods

Our prospective study was approved by our institutional review board and informed consent was obtained from all participating patients. For patients with viable HCC around retained iodized oil after TACE, biplane fluoroscopy plus US-guided RFA was performed. We evaluated the rate of technical success and major complications on a post-RFA CT examination and local tumor progression with a follow-up CT.

Results

Among 40 consecutive patients, 19 were excluded due to one of the following reasons: poorly visible HCC on fluoroscopy (n = 13), high risk location (n = 2), RFA performed under monoplane fluoroscopy and US guidance (n = 2), and poorly identifiable new HCCs on US (n = 2). The remaining 21 patients with 21 viable HCCs were included. The size of total tumors ranged from 1.4 to 5.0 cm (mean: 3.2 cm) in the longest diameter. Technical success was achieved for all 21 HCCs, and major complications were observed in none of the patients. During the follow-up period (mean, 20.3 months; range, 6.5-29.9 months), local tumor progression was found in two patients (2/21, 9.5%). Distant intrahepatic metastasis developed in 76.2% (16/21) of patients.

Conclusion

When retained iodized oil around the tumor after TACE hampers the targeting of the viable tumor for RFA, biplane fluoroscopy plus US-guided RFA may be performed owing to its technical feasibility and effective treatment for viable HCCs.     

Pretreatment Evaluation with Contrast-Enhanced Ultrasonography for Percutaneous Radiofrequency Ablation of Hepatocellular Carcinomas with Poor Conspicuity on Conventional Ultrasonography

Objective

To determine whether pretreatment evaluation with contrast-enhanced ultrasonography (CEUS) is effective for percutaneous radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC) with poor conspicuity on conventional ultrasonography (US).

Materials and Methods

This retrospective study was approved by the institutional review board and informed consent was waived. From June 2008 to July 2011, 82 patients having HCCs (1.2 ± 0.4 cm) with poor conspicuity on planning US for RFA were evaluated with CEUS prior to percutaneous RFA. We analyzed our database, radiologic reports, and US images in order to determine whether the location of HCC candidates on planning US coincide with that on CEUS. To avoid incomplete ablation, percutaneous RFA was performed only when HCC nodules were identified on CEUS. The rate of technical success was assessed. The cumulative rate of local tumor progression was estimated with the use of the Kaplan-Meier method (mean follow-up: 24.0 ± 13.0 months).

Results

Among 82 patients, 73 (89%) HCCs were identified on CEUS, whereas 9 (11%) were not. Of 73 identifiable HCCs on CEUS, the location of HCC on planning US corresponded with that on CEUS in 64 (87.7%), whereas the location did not correspond in 9 (12.3%) HCCs. Technical success was achieved for all 73 identifiable HCCs on CEUS in a single (n = 72) or two (n = 1) RFA sessions. Cumulative rates of local tumor progression were estimated as 1.9% and 15.4% at 1 and 3 years, respectively.

Conclusion

Pretreatment evaluation with CEUS is effective for percutaneous RFA of HCCs with poor conspicuity on conventional US.     

Radiofrequency Ablation Combined with Chemoembolization for Intermediate-Sized (3-5 cm) Hepatocellular Carcinomas Under Dual Guidance of Biplane Fluoroscopy and Ultrasonography

Objective

To assess the technical feasibility and local efficacy of percutaneous radiofrequency ablation (RFA) combined with transcatheter arterial chemoembolization (TACE) for an intermediate-sized (3-5 cm in diameter) hepatocellular carcinoma (HCC) under the dual guidance of biplane fluoroscopy and ultrasonography (US).

Materials and Methods

Patients with intermediate-sized HCCs were treated with percutaneous RFA combined with TACE. RFA was performed under the dual guidance of biplane fluoroscopy and US within 14 days after TACE. We evaluated the rate of major complications on immediate post-RFA CT images. Primary technique effectiveness rate was determined on one month follow-up CT images. The cumulative rate of local tumor progression was estimated with the use of Kaplan-Meier method.

Results

Twenty-one consecutive patients with 21 HCCs (mean size: 3.6 cm; range: 3-4.5 cm) were included. After TACE (mean: 6.7 d; range: 1-14 d), 20 (95.2%) of 21 HCCs were visible on fluoroscopy and were ablated under dual guidance of biplane fluoroscopy and US. The other HCC that was poorly visible by fluoroscopy was ablated under US guidance alone. Major complications were observed in only one patient (pneumothorax). Primary technique effectiveness was achieved for all 21 HCCs in a single RFA session. Cumulative rates of local tumor progression were estimated as 9.5% and 19.0% at one and three years, respectively.

Conclusion

RFA combined with TACE under dual guidance of biplane fluoroscopy and US is technically feasible and effective for intermediate-sized HCC treatment.     

Radiofrequency Ablation of Renal Tumors: Four-Year Follow-Up Results in 47 Patients

Objective

To retrospectively evaluate the intermediate results of radiofrequency ablation (RFA) of small renal masses (SRMs).

Materials and Methods

Percutaneous or laparoscopic RFA was performed on 48 renal tumors in 47 patients. The follow-up studies included a physical examination, chest radiography, creatinine level, and contrast-enhanced CT or MRI. To confirm the pathologic criteria of complete ablation, 35 patients underwent a follow-up biopsy. Recurrence was defined as contrast enhancement on imaging studies after 3 months, lesion growth at subsequent imaging, or viable cancer cells on follow-up biopsy.

Results

Technical success was achieved in 43 (89.6%) of 48 renal tumors. The mean tumor size was 2.3 cm and the mean follow-up period was 49.6 months. Repeated RFA was necessary in 5 tumors due to incomplete ablation. The overall complication rate was 35.8%, of which 96.2% were mild complications. Serum creatinine levels at 12 months after RFA did not differ from those before RFA (1.28 vs. 1.36 mg/dL). Four patients were found to have recurrence at various follow-up intervals, and distant metastasis was not found in any cases.

Conclusion

RFA appears to be a useful treatment for selected patients with SRMs. Our 4-year follow-up results disclose an excellent therapeutic outcome with RFA, while achieving effective local tumor control.     

Radiofrequency Ablation for Treating Liver Metastases from a Non-Colorectal Origin

Objective

We wanted to assess the safety and efficacy of performing radiofrequency ablation (RFA) in patients with non-colorectal liver metastases.

Materials and Methods

In this retrospective study, 25 patients with 40 hepatic metastases (M:F = 17:8; mean age, 57 years; tumor size, 0.5-5.0 cm) from a non-colorectal origin (stomach, biliary, breast, pancreas, kidney and skin) were treated with RFA. The RFA procedures were performed using either an internally cooled electrode or a clustered electrode under ultrasound or CT guidance. Contrast-enhanced CT scans were obtained immediately after RFA and follow-up CT scans were performed within three months after ablation and subsequently at least every six months. The intrahepatic disease-free interval was estimated and the overall survival from the time of the initial RFA was analyzed using the Kaplan-Meier method.

Results

No intraprocedural deaths occurred, but four major complications developed, including abscesses (n = 3) and pneumothorax (n = 1). Technical effectiveness was determined on the initial follow-up images. During the follow-up period (range, 5.9-68.6 months; median time, 18.8 months) for 37 tumors in 22 patients where technical effectiveness was achieved, 12 lesions (32%, 12 of 37) showed local tumor progression and new intrahepatic metastases occurred in 13 patients (59%, 13 of 22). The median intrahepatic disease-free interval was 10.1 months. The 1-year, 3-year and 5-year overall survival rates after RFA were 86%, 39% and 19%, respectively.

Conclusion

RFA showed intermediate therapeutic effectiveness for the treatment of non-colorectal origin liver metastases.     

Percutaneous Radiofrequency Ablation with Multiple Electrodes for Medium-Sized Hepatocellular Carcinomas

Objective

To prospectively evaluate the safety and short-term therapeutic efficacy of switching monopolar radiofrequency ablation (RFA) with multiple electrodes to treat medium-sized (3.1-5.0 cm), hepatocellular carcinomas (HCC).

Materials and Methods

In this prospective study, 30 patients with single medium-sized HCCs (mean, 3.5 cm; range, 3.1-4.4 cm) were enrolled. The patients were treated under ultrasonographic guidance by percutaneous switching monopolar RFA with a multichannel RF generator and two or three internally cooled electrodes. Contrast-enhanced CT scans were obtained immediately after RFA, and the diameters and volume of the ablation zones were then measured. Follow-up CT scans were performed at the first month after ablation and every three months thereafter. Technical effectiveness, local progression and remote recurrence of HCCs were determined.

Results

There were no major immediate or periprocedural complications. However, there was one bile duct stricture during the follow-up period. Technical effectiveness was achieved in 29 of 30 patients (97%). The total ablation time of the procedures was 25.4 ± 8.9 minutes. The mean ablation volume was 73.8 ± 56.4 cm³ and the minimum diameter was 4.1 ± 7.3 cm. During the follow-up period (mean, 12.5 months), local tumor progression occurred in three of 29 patients (10%) with technical effectiveness, while new HCCs were detected in six of 29 patients (21%).

Conclusion

Switching monopolar RFA with multiple electrodes in order to achieve a sufficient ablation volume is safe and efficient. This method also showed relatively successful therapeutic effectiveness on short-term follow up for the treatment of medium-sized HCCs.     

Therapeutic Efficacy and Safety of Percutaneous Ethanol Injection with or without Combined Radiofrequency Ablation for Hepatocellular Carcinomas in High Risk Locations

Objective

To evaluate the therapeutic efficacy and safety of percutaneous ethanol injection (PEI) alone and combined with radiofrequency ablation (RFA) for hepatocellular carcinomas (HCCs) in high risk locations.

Materials and Methods

We performed PEI for HCCs in RFA-high risk locations, either alone or in combination with RFA. There were 20 HCCs (1.7 ± 0.9 cm) in 20 patients (PEI group: n = 12; PEI + RFA group: n = 8). We evaluated technical success, local tumor progression and complications in both groups.

Results

Technical success was achieved in all HCCs in both groups. During follow-up, local tumor progression was found in 41.7% (5/12) in the PEI group, whereas 12.5% (1/8) for the PEI + RFA group (p = 0.32). Bile duct dilatation was the most common complication, especially when the tumors were in periportal locations; 55% (5/9) in the PEI group and 50% (2/4) in the PEI + RFA group (p = 1.00). One patient in the PEI group developed severe biliary stricture and upstream dilatation that resulted in atrophy of the left hepatic lobe. One patient treated with PEI + RFA developed cholangitis and an abscess.

Conclusion

Combined PEI and RFA treatment has a tendency to be more effective than PEI alone for managing HCCs in high risk locations, although the difference is not statistically significant. Even though PEI is generally accepted as a safe procedure, it may cause major biliary complications for managing HCCs adjacent to the portal vein.     

Guidewire-catheter induced hydrodissection to assist radiofrequency ablation for subcapsular hepatocellular carcinoma with iodized oil retention in patients with failed artificial ascites due to perihepatic adhesion

PURPOSEWe aimed to evaluate the usefulness of guidewire-catheter induced hydrodissection (GIH) to assist radiofrequency ablation (RFA) for subcapsular hepatocellular carcinoma (HCC) with iodized oil retention in patients with failed artificial ascites due to perihepatic adhesion.METHODSThis retrospective study included 17 patients with small subcapsular HCC ineligible for ultrasonography-guided RFA who received RFA under guidance of fluoroscopy and cone-beam computed tomography immediately after iodized oil transarterial chemoembolization (TACE) between April 2011 and January 2016. In the study patients, creation of artificial ascites to protect the perihepatic structures failed due to perihepatic adhesion and GIH was attempted to separate the perihepatic structures from the ablation zone. The technical success rate of GIH, technique efficacy of RFA with GIH, local tumor progression (LTP), peritoneal seeding, and complications were evaluated.RESULTSThe technical success rate of GIH was 88.24% (15 of 17 patients). Technique efficacy was achieved in all 15 patients receiving RFA with GIH. During an average follow-up period of 48.1 months, LTP developed in three patients. Cumulative LTP rates at 1, 2, 3, and 5 years were 13.3%, 20.6%, 20.6%, and 20.6%, respectively. No patient had peritoneal seeding. Two of the 15 patients receiving RFA with GIH had a CIRSE grade 3 liver abscess, but none had complications associated with thermal injury to the diaphragm or abdominal wall near the ablation zone.CONCLUSIONGIH can be a useful method to assist RFA for subcapsular HCC with iodized oil retention in patients with failed artificial ascites due to perihepatic adhesion.

Radiofrequency ablation (RFA) is widely accepted as a curative treatment for patients with small (≤3 cm) hepatocellular carcinoma (HCC) not suitable for surgery (1, 2). However, when the tumor is located close to the liver surface, RFA carries a risk of unintended collateral thermal injury to the perihepatic structures (i.e., diaphragm and abdominal wall). To overcome this problem, adjunctive techniques such as introduction of artificial ascites or pleural effusion have been applied (3–8). Nonetheless, patients with perihepatic peritoneal adhesion may still be at risk of collateral thermal injury as adhesion prevents separation of the perihepatic structures by artificial ascites from the ablation zone (6, 9, 10). Some investigators have used an alternative technique making localized hydrodissection by using an 18–22 G needle at the contact point between the index tumor and perihepatic structure (9, 11). However, this also seems to be not applicable when the lung or bowel interposes on the access route.Prior iodized oil transarterial chemoembolization (TACE) enhances the feasibility of subsequent RFA for small tumors with poor conspicuity (12, 13). This is because intratumoral retention of radio-opaque iodized oil provides radiographic contrast to the index tumor. As the index tumor with iodized oil retention is clearly seen on fluoroscopy and the perihepatic peritoneal space is easily accessed by traditional methods of making artificial ascites (6, 9, 14), an angiographic catheter and guidewire system can reach the region near the tumor through the perihepatic space under fluoroscopic guidance. Therefore, in patients with perihepatic adhesion, if forceful advancement of the catheter and guidewire system could dissect the adhesion, introduction of fluid via the catheter tip at the region near the tumor may protect the perihepatic structures from thermal injury during RFA for subcapsular HCC.The aim of this study was to evaluate the usefulness of guidewire-catheter induced hydrodissection (GIH) to assist RFA for subcapsular HCC with iodized oil retention in patients with failed artificial ascites due to perihepatic adhesion.     

Transcatheter Arterial Embolization with a Mixture of Absolute Ethanol and Iodized Oil for Poorly Visualized Endophytic Renal Masses Prior to CT-Guided Percutaneous Cryoablation

Purpose

To retrospectively evaluate the feasibility of transcatheter arterial embolization (TAE) using a mixture of absolute ethanol and iodized oil to improve localization of endophytic renal masses on unenhanced computed tomography (CT) prior to CT-guided percutaneous cryoablation (PCA).

Materials and Methods

Our institutional review board approved this retrospective study. From September 2011 to June 2015, 17 patients (mean age, 66.8 years) with stage T1a endophytic renal masses (mean diameter, 26.5 mm) underwent TAE using a mixture of absolute ethanol and iodized oil to improve visualization of small and endophytic renal masses on unenhanced CT prior to CT-guided PCA. TAE was considered successful that accumulated iodized oil depicted whole of the tumor edge on CT. PCA was considered successful when the iceball covered the entire tumor with over a 5 mm margin. Oncological and renal functional outcomes and complications were also evaluated.

Results

TAE was successfully performed in 16 of 17 endophytic tumors. The 16 tumors were performed under CT-guided PCA with their distinct visualization of localization and safe ablated margin. During the mean follow-up period of 15.4 ± 5.1 months, one patient developed local recurrence. Estimated glomerular filtration rate declined by 8 % with statistical significance (P = 0.01). There was no procedure-related significant complication.

Conclusion

TAE using a mixture of absolute ethanol and iodized oil to improve visualization of endophytic renal masses facilitated tumor localization on unenhanced CT, permitting depiction of the tumor edge as well as a safe margin for ablation during CT-guided PCA, with an acceptable decline in renal function.

     

Hepatocellular carcinomas 2-3 cm in diameter: transarterial chemoembolization plus radiofrequency ablation vs. radiofrequency ablation alone

Objective

There is debate whether transarterial chemoembolization (TACE) plus radiofrequency ablation (RFA) is more effective than RFA alone in the treatment of patients with small hepatocellular carcinoma (HCC). We therefore retrospectively compared these treatments in patients with HCCs of diameter 2–3 cm.

Materials and methods

Outcomes, including tumor progression, survival rates, and major complications, were compared in 83 patients (83 tumors) treated with combined TACE and RFA and in 231 patients (231 tumors) treated with RFA alone.

Results

Median follow-up periods were similar in the TACE + RFA and RFA alone groups (37 vs. 38 months). During follow-up, local tumor progression was observed in 16% and 41% of tumors, respectively. The 1, 3, and 5 year local tumor progression-free survival rates were significantly higher in the TACE + RFA group (95%, 86%, and 83%, respectively) than in the RFA-alone group (78%, 61%, and 53%, respectively; P < 0.001). The 1, 3, and 5 year overall survival rates, however, were similar in the TACE + RFA (93%, 72%, and 63%, respectively) and RFA (93%, 73%, and 53%, respectively) groups (P = 0.545), as were the rates of major complications (1.2% vs. 0.4%).

Conclusions

Combined TACE and RFA was safe and provided better local tumor control than RFA alone in the treatment of 2- to 3-cm sized HCCs, although survival rates were similar.     

Local Recurrence of Hepatocellular Carcinoma after Segmental Transarterial Chemoembolization: Risk Estimates Based on Multiple Prognostic Factors

Objective

To determine the prognostic factors for local recurrence of nodular hepatocellular carcinoma after segmental transarterial chemoembolization.

Materials and Methods

Seventy-four nodular hepatocellular carcinoma tumors ≤ 5 cm were retrospectively analyzed for local recurrence after segmental transarterial chemoembolization using follow-up CT images (median follow-up of 17 months, 4-77 months in range). The tumors were divided into four groups (IA, IB, IIA, and IIB) according to whether the one-month follow-up CT imaging, after segmental transarterial chemoembolization, showed homogeneous (Group I) or inhomogeneous (Group II) iodized oil accumulation, or whether the tumors were located within the liver segment (Group A) or in a segmental border zone (Group B). Comparison of tumor characteristics between Group IA and the other three groups was performed using the chi-square test. Local recurrence rates were compared among the groups using the Kaplan-Meier estimation and log rank test.

Results

Local tumor recurrence occurred in 19 hepatocellular carcinoma tumors (25.7%). There were: 28, 18, 17, and 11 tumors in Group IA, IB, IIA, and IIB, respectively. One of 28 (3.6%) tumors in Group IA, and 18 of 46 (39.1%) tumors in the other three groups showed local recurrence. Comparisons between Group IA and the other three groups showed that the tumor characteristics were similar. One-, two-, and three-year estimated local recurrence rates in Group IA were 0%, 11.1%, and 11.1%, respectively. The difference between Group IA and the other three groups was statistically significant (p = 0.000).

Conclusion

An acceptably low rate of local recurrence was observed for small or intermediate nodular tumors located within the liver segment with homogeneous iodized oil accumulation.     

Image-guided radiofrequency ablation of hepatocellular carcinoma (HCC): Is MR guidance more effective than CT guidance?

Objectives

The purpose of the study was to retrospectively compare technique effectiveness of computed tomography (CT)-guided versus magnetic resonance (MR)-guided radiofrequency (RF) ablation of hepatocellular carcinoma (HCC).

Materials and methods

In 35 consecutive patients 53 CT-guided (n = 29) or MR-guided (n = 24) ablation procedures were performed in the treatment of 56 (CT: 29; MR: 27) HCC. The entire ablation procedure was performed at a multislice CT-scanner or an interventional 0.2-Tesla MR-scanner. Assessment of treatment response was based on dynamic MR imaging at 1.5 Tesla. The mean follow-up was 22.9 months. Primary technique effectiveness was assessed 4 months after ablation therapy. Secondary technique effectiveness was assessed 4 months after a facultative second ablation procedure. Primary and secondary technique effectiveness of CT-guided and MR-guided RF ablation was compared by using Chi-Square (likelihood ratio) test.

Results

Primary technique effectiveness after a single session was achieved in 26/27 (96.3%) HCC after MR-guided RF ablation and 23/29 (79.3%) HCC after CT-guided RF ablation (Chi-Square: p = 0.04). Secondary technique effectiveness was achieved in 26/27 (96.3%) HCC after MR-guided RF ablation and in 26/29 (89.7%) HCC after CT-guided RF ablation (Chi-Square: p = 0.32). A local tumor progression was detected in 8/52 (15.4%) tumors after initial technique effectiveness. Major complications were detected after 3/53 (5.7%) ablation procedures.

Conclusions

CT-guided and MR-guided RF ablations are locally effective therapies in the treatment of HCC. Due to a higher rate of primary technique effectiveness MR-guided RF ablation may reduce the number of required sessions for complete tumor treatment.     

Biplane fluoroscopy-guided radiofrequency ablation combined with chemoembolisation for hepatocellular carcinoma: initial experience

Objective

The purpose of this study was to assess the technical feasibility and local efficacy of biplane fluoroscopy-guided percutaneous radiofrequency (RF) ablation combined with transcatheter arterial chemoembolisation (TACE) for hepatocellular carcinoma (HCC).

Method

Our retrospective study was approved by the institutional review board and informed consent was waived. 18 patients with 19 HCCs (mean 2.5 cm diameter; range 2–4.2 cm) were treated with percutaneous RF ablation combined with TACE. After segmental TACE, 18 (95%) of 19 HCCs were visible on fluoroscopy. Shortly (median 2 days; range 1–4 days) after TACE, percutaneous RF ablation was performed under real-time biplane fluoroscopic guidance. We evaluated major complications, rate of technical success at immediate post-RF ablation CT images and local tumour progression at follow-up CT images.

Results

Major complication was not observed in any patients. Technical success was achieved for all 18 visible HCCs. During the follow-up period (median 20 months; range 5–30 months), no local tumour progression was found.

Conclusion

Biplane fluoroscopy-guided RF ablation combined with TACE is technically feasible and effective for treatment of HCC.Percutaneous radiofrequency (RF) ablation has been widely implemented in the management of hepatocellular carcinoma (HCC) with promising results. Although its local efficacy for small tumours (i.e. <2 cm) is similar to surgical outcomes [1], results for medium-sized and large tumours are less robust. Thus, multimodal treatments such as combined percutaneous RF ablation with transarterial chemoembolisation (TACE) have been explored for medium or large HCCs in order to enhance the therapeutic effect. In a recent study, RF ablation combined with TACE was similar to surgical resection in patients with early-stage disease [2].Percutaneous RF ablation shortly following TACE has been usually performed under guidance of either ultrasonography or CT/CT fluoroscopy. Since intratumoural retention of radio-opaque iodised oil induced by TACE conveniently provides radiographic contrast to the index lesion, biplane fluoroscopy (anterior posterior and lateral projections) can be used as an alternative guiding modality for RF ablation combined with TACE. Easier targeting of dome lesions, often difficult to visualise on ultrasound, through an oblique approach without pleural transgression is one potential advantage of biplane fluoroscopy guidance. Also unlike on ultrasound, microbubble formation during ablation would not obscure the index lesion on biplane fluoroscopy, allowing easier and more spatially accurate application of overlapping ablations that are often needed for larger tumours. However, to our knowledge, there have been no studies investigating the role of biplane fluoroscopy as a guidance modality in this clinical setting. The purpose of our study was to retrospectively assess the technical feasibility and local efficacy of biplane fluoroscopy-guided percutaneous RF ablation combined with TACE for HCC ≥2 cm.     

Saline-Enhanced Radiofrequency Thermal Ablation of the Lung: A Feasibility Study in Rabbits

Objective

To assess the feasibility and safety of CT-guided percutaneous transthoracic radiofrequency ablation (RFA) with saline infusion of pulmonary tissue in rabbits.

Materials and Methods

Twenty-eight New Zealand White rabbits were divided into two groups: an RFA group (n=10) and a saline-enhanced RFA (SRFA) group (n=18). In the RFA group, percutaneous RFA of the lung was performed under CT guidance and using a 17-gauge internally cooled electrode. In the SRFA group, 1.5 ml of 0.9% saline was infused slowly through a 21-gauge, polyteflon-coated Chiba needle prior to and during RFA. Lesion size and the healing process were studied in rabbits sacrificed at times from the day following treatment to three weeks after, and any complications were noted.

Results

In the SRFA group, the mean diameter (12.5 ± 1.6 mm) of acute RF lesions was greater than that of RFA lesions (8.5 ± 1.4 mm) (p < .05). The complications arising in 12 cases were pneumothorax (n=8), thermal injury to the chest wall (n=2), hemothorax (n=1), and lung abscess (n=1). Although procedure-related complications tended to occur more frequently in the SRFA group (55.6%) than in the RFA group (20%), the difference was not statistically significant (p = .11).

Conclusion

Saline-enhanced RFA of pulmonary tissue in rabbits produces more extensive coagulation necrosis than conventional RFA procedures, without adding substantial risk of serious complications.     

Radiofrequency ablation under 3D intraoperative Iso-C C-arm navigation for the treatment of osteoid osteomas

Objective:

To evaluate the efficacy of intraoperative three-dimensional (3D) Iso-C C-arm-navigated percutaneous radiofrequency ablation (RFA) of osteoid osteomas.

Methods:

35 patients (20 males and 15 females) with osteoid osteomas underwent treatment with intraoperative 3D Iso-C C-arm navigation-guided RFA. The tumour was first biopsied for pathological examination, the core needle was removed and the RFA needle was inserted into the nidus. Post-operative X-rays and CT scans were performed to evaluate the degree of ablation and to assess for recurrence at 3-month follow-up. Patients also completed a visual analogue scale (VAS) both pre-operatively and 3 days post-operatively to subjectively assess pain.

Results:

Pathological diagnosis confirmed osteoid osteoma in 19 cases. The other 16 cases were not pathologically diagnosed owing to inadequate biopsy specimens. In all cases, localized pain was immediately relieved following RFA. Patients reported significantly decreased pain, with mean pre-operative VAS scores of 3.4 reducing to 0.80 at 3 days post-operatively and further to 0.06 at 3-month follow-up (p < 0.05). The mean follow-up time was 15.5 months (range: 3–38 months).

Conclusion:

3D Iso-C C-arm navigation-guided RFA is a safe and effective option for the treatment of osteoid osteomas and may be considered in place of intraoperative CT-guided and open resection.

Advances in knowledge:

C-arm image-guided percutaneous RFA mitigates the need for pre-operative CT as well as intraoperative scintigraphy, provides real-time imaging of the anatomy, facilitates accurate resection of the tumour and enables immediate confirmation of excision.     

Comparison of therapeutic efficacy and safety of radiofrequency ablation of hepatocellular carcinomas between internally cooled 15-G and 17-G single electrodes

Objective:

To compare the ablation volume, local tumour progression rate and complication rate of radiofrequency ablation (RFA) for small hepatocellular carcinomas (HCCs) using 15-G and 17-G single electrodes.

Methods:

This retrospective study was approved by the institutional review board and informed consent was waived. We reviewed percutaneous RFA cases for HCCs using 15-G or 17-G electrodes without multiple overlapping ablations. A total of 36 pairs of HCCs matched according to tumour size and active tip length were included. We compared ablation volume and complication rate between the two electrode groups. Cumulative local tumour progression rates were estimated using the Kaplan–Meier method and compared using the log-rank test.

Results:

Tumour size and ablation time were not significantly different between the 15-G and 17-G groups (p = 0.661 and p = 0.793, respectively). However, ablation volume in the 15-G electrode group was larger than that in the 17-G group (14.4 ± 5.4 cm³ vs 8.7 ± 2.5 cm³; p < 0.001). No statistical difference in complication rates between the two electrode groups was found. The 10- and 20-month local tumour progression rates were not significantly different between the two groups (2.8% and 5.6% vs 11.1% and 19.3%; p = 0.166).

Conclusion:

Ablation volume by the 15-G electrode was larger than that by the 17-G electrode. However, local tumour progression rate and complication rate were not significantly different between the two electrode groups.

Advances in knowledge:

RFA of HCC using a 15-G electrode is useful to create larger ablation volumes than a 17-G electrode.Radiofrequency ablation (RFA) is now considered to be one of the curative treatment modalities for the management of small hepatocellular carcinomas (HCCs).^1–5 There are various types of electrodes for RFA, including internally cooled electrodes, multi-tined electrodes and perfusion electrodes.^6,7 Among them, an internally cooled electrode is frequently used because it is simple and easy to use. The ablation zone created by an internally cooled electrode is usually cylindrical in shape along the longitudinal axis of the electrode. Hence, the horizontal diameter of the ablation zone is relatively smaller than the longitudinal diameter. Therefore, an internally cooled electrode frequently requires overlapping ablations to achieve a sufficient ablative margin for large tumours (i.e. size >2.5 cm). However, it is sometimes technically difficult to achieve a sufficient ablative margin under ultrasonography guidance since both the boundary of the index tumour and the active tip of the electrode are obscured by the echogenic zone generated by the previous ablation cycle. Therefore, it is ideal to achieve a large ablation zone using a single electrode without multiple overlapping ablations.Electrodes with a larger diameter have a larger contact surface with the surrounding tissue than smaller ones and thereby have a higher active electric field.^8–10 This in turn delivers a larger amount of radiofrequency energy and thus produces a greater amount of heat around the active tip. Consequently, large electrodes create large ablation zones. However, to our knowledge, commercially available internally cooled electrodes are not large and are almost exclusively 17-G.^11,12Recently, larger sized 15-G electrodes have been introduced and used for RFA of liver tumours in our institution. We have found that the 15-G electrode created a larger ablation volume than did the 17-G electrode, while the complication rate differed little. However, to our knowledge, there are no comparative data in the literature regarding the therapeutic efficacy and complication rate after RFA between 15-G and 17-G single electrodes. Hence, the purpose of this study was to evaluate and compare the ablation volume, local tumour progression rate and complication rate after RFA of HCCs using 15-G and 17-G single electrodes.     

Percutaneous Radiofrequency Ablation of Hepatocellular Carcinomas Adjacent to the Gallbladder with Internally Cooled Electrodes: Assessment of Safety and Therapeutic Efficacy

Objective

The objective of this study was to evaluate the safety and therapeutic efficacy of percutaneous radiofrequency (RF) ablation for the treatment of hepatocellular carcinomas (HCCs) adjacent to the gallbladder with the use of internally cooled electrodes.

Materials and Methods

We retrospectively assessed 45 patients with 46 HCCs (mean size, 2.2 cm) adjacent to the gallbladder (≤1.0 cm) treated with RF ablation using an internally cooled electrode system. An electrode was inserted into the tumor either parallel (n = 38) or perpendicular (n = 8) to the gallbladder wall. The safety and therapeutic efficacy of the procedures were assessed with clinical and imaging follow-up examinations. Follow-up with the use of CT ranged from four to 45 months (mean, 19 months). The association between variables (electrode direction, electrode type, tumor size, tumor location, lobar location) and the presence of a residual tumor or local tumor progression was also analyzed.

Results

There were no major complications and minor complications were noted in three patients (7%) including one case of vasovagal syncope and two cases of bilomas. Wall thickening of the gallbladder adjacent to the RF ablation zone was noted in 14 patients (41%) as determined on immediate follow-up CT imaging. Wall thickening showed complete disappearance on subsequent follow-up CT imaging. The primary technique effectiveness rate was 96% (44/46) based on one-month follow-up CT imaging. Local tumor progression was noted in six (14%) of 44 completely ablated tumors during the follow-up period. The direction of electrode insertion (perpendicular), tumor size (≥3 cm) and tumor location (a tumor that abutted the gallbladder) were associated with an increased risk of early incomplete treatment. No variable was significantly associated with local tumor progression.

Conclusion

Percutaneous RF ablation of HCCs adjacent to the gallbladder using an internally cooled electrode is a safe and effective treatment. Significant risk factors that lead to early incomplete treatment include tumor size, tumor location and electrode direction.     

Radiofrequency ablation of subcapsular hepatocellular carcinoma: Single center experience

Purpose

To present a single center results, regarding radiofrequency ablation (RFA) of subcapsular hepatocellular carcinoma (HCC).

Materials and methods

Forty patients with subcapsular HCC were treated with RFA under CT guidance for fifty-two discrete lesions in our institution. Twenty-eight patients underwent ablation of a solitary tumor and twelve patients underwent RFA of two tumors. Six patients had a subcapsular HCC with an exofitic location. All lesions had a diameter of <4 cm. We used two types of generators and electrodes: spiral electrode and expandable electrode. Needle track ablation was performed in all cases. Follow-up consisted of an abdomen computed tomography (CT) scan after contrast administration immediately after each session and then after one, three, six, and twelve months.

Results

In forty-eight lesions complete tumor ablation was depicted at the one month CT scan. In four lesions with residual viable tumor, a second session was performed. After the second ablation no residual tumor was observed in any patient. No major complications occurred in any of our patients. Fever with a temperature up to 39 °C was documented during the first days as part of the post-ablation syndrome in thirteen patients (32.2%). Seeding along the needle track was observed in none of our patients. Local tumor progression, was observed in ten lesions (19.25%) and in all cases a second RFA session was performed with optimal results.

Conclusion

Subcapsular location should not be considered as a contraindication for liver RFA.     

Percutaneous Radiofrequency Ablation for the Hepatocellular Carcinoma Abutting the Diaphragm: Assessment of Safety and Therapeutic Efficacy

Objective

To assess the safety and therapeutic efficacy of a percutaneous radiofrequency (RF) ablation for the hepatocellular carcinoma (HCC) abutting the diaphragm.

Materials and Methods

We retrospectively assessed 80 patients who underwent a percutaneous RF ablation for a single nodular (< 4 cm) HCC over the last four years. Each patient underwent an ultrasound-guided RF ablation using internally cooled electrodes for the first-line treatment. We divided patients into two subgroups based on whether the index tumor was abutting (less than 5 mm) the diaphragm or not: group A (abutting; n = 31) versus group B (non-abutting; n = 49). We compared the two subgroups for complications and therapeutic efficacy using image and the review of medical records. The statistical assessment included an independent t-test, Fisher''s exact test, and chi-square test.

Results

The assessment of the diaphragmatic swelling at CT immediately following the procedure was more severe in group A than group B (mean thickness change:1.44 vs. 0.46 mm, p = 0.00). Further, right shoulder pain was more common in group A than B (p = 0.01). Although minor complications (hemothorax 1 case, pleural effusion 1 case) were noted only in group A, no major thoracic complication occurred in either group. The technical success rate was lower in group A than group B (84% vs. 98%, p = 0.03). As well, the primary and secondary technique effectiveness rates in group A and group B were 90% versus 98% (p = 0.29) and 79% versus 91% (p = 0.25), respectively. The local tumor progression rate was higher in group A than in group B (29% vs. 6%, p = 0.02).

Conclusion

We found that the percutaneous RF ablation for the HCC abutting the diaphragm is a safe procedure without major complications. However, it is less effective with regard to technical success and local tumor control.     

Comparative survival analysis in patients with pulmonary metastases from nasopharyngeal carcinoma treated with radiofrequency ablation

Purpose

The aim of this retrospective study was to evaluate technical efficacy and the impact of CT-guided pulmonary radiofrequency ablation (RFA) on survival in patients with pulmonary metastases from nasopharyngeal carcinoma (NPC).

Materials and methods

Between 2000 and 2009, 480 patients were pathologically or clinically confirmed pulmonary metastases from NPC. And ten included patients of them had a total of 23 pulmonary metastases treated with percutaneous RFA under the real-time CT fluoroscopy. Safety, local tumor progression, and survival were evaluated in our institutions. Matched-pair survival was compared using Kaplan–Meier analysis.

Results

A total of 25 ablations were performed to 23 pulmonary metastases in 13 RFA sessions. Pneumothorax requiring chest tube placement developed in 3 of 13 (23.1%) RFA sessions. The median metastatic overall survival was 36.1 months for all the 480 NPC patients with pulmonary metastases. Furthermore, matched-pair analysis demonstrated patients with RFA treatment had a greater metastatic overall survival than patients without RFA treatment (77.1 months vs 32.4 months, log-rank test, p = 0.009). There were no statistically significant differences in the survival probability of patients with RFA treatment (n = 10) and surgical resection of pulmonary metastases (n = 27) (log-rank test, p = 0.75).

Conclusion

CT-guided pulmonary RFA is safe and offers a treatment alternative for local tumor control, providing promising survival in selected patients with pulmonary metastases from NPC.