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Ultrasound-Guided Percutaneous Radiofrequency Ablation of Liver Tumors: How We Do It Safely and Completely.

Kim JW, Shin SS, Heo SH, Hong JH, Lim HS, Seon HJ, Hur YH, Park CH, Jeong YY, Kang HK - Korean J Radiol (2015)

Bottom Line: Although RF ablation is a safe and effective technique for the treatment of liver tumors, the outcome of treatment can be closely related to the location and shape of the tumors.Thus, a number of strategies have been developed to overcome these challenges, which include artificial ascites, needle track ablation, fusion imaging guidance, parallel targeting, bypass targeting, etc.This article offers technical strategies that can be used to effectively perform RF ablation as well as to minimize possible complications related to the procedure with representative cases and schematic illustrations.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Chonnam National University Medical School, Gwangju 61469, Korea.

ABSTRACT
Ultrasound-guided percutaneous radiofrequency (RF) ablation has become one of the most promising local cancer therapies for both resectable and nonresectable hepatic tumors. Although RF ablation is a safe and effective technique for the treatment of liver tumors, the outcome of treatment can be closely related to the location and shape of the tumors. There may be difficulties with RF ablation of tumors that are adjacent to large vessels or extrahepatic heat-vulnerable organs and tumors in the caudate lobe, possibly resulting in major complications or treatment failure. Thus, a number of strategies have been developed to overcome these challenges, which include artificial ascites, needle track ablation, fusion imaging guidance, parallel targeting, bypass targeting, etc. Operators need to use the right strategy in the right situation to avoid the possibility of complications and incomplete thermal tissue destruction; with the right strategy, RF ablation can be performed successfully, even for hepatic tumors in high-risk locations. This article offers technical strategies that can be used to effectively perform RF ablation as well as to minimize possible complications related to the procedure with representative cases and schematic illustrations.

No MeSH data available.


Related in: MedlinePlus

RF ablation using parallel targeting along large vessel in 50-year-old man.A. Gadoxetic acid-enhanced axial hepatobiliary-phase T1-weighted image shows metastasis (arrow) from rectal cancer in segment 7 abutting right hepatic vein (arrowhead). B. Intercostal US image depicts hypoechoic metastasis (arrowhead) abutting right hepatic vein (arrow), which can potentially cause heat-sink effect during RF ablation. C. Intercostal US image during procedure demonstrates needle (arrow) in parallel to right hepatic vein (arrowhead) in order to enlarge contact surface between ablation zone and vessel. D. Immediate follow-up contrast-enhanced CT image shows elongated low-attenuated RF ablation zone (asterisk) along right hepatic vein (arrowhead), which sufficiently covers index tumor, as well as intact right hepatic vein. RF = radiofrequency, US = ultrasound
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Figure 7: RF ablation using parallel targeting along large vessel in 50-year-old man.A. Gadoxetic acid-enhanced axial hepatobiliary-phase T1-weighted image shows metastasis (arrow) from rectal cancer in segment 7 abutting right hepatic vein (arrowhead). B. Intercostal US image depicts hypoechoic metastasis (arrowhead) abutting right hepatic vein (arrow), which can potentially cause heat-sink effect during RF ablation. C. Intercostal US image during procedure demonstrates needle (arrow) in parallel to right hepatic vein (arrowhead) in order to enlarge contact surface between ablation zone and vessel. D. Immediate follow-up contrast-enhanced CT image shows elongated low-attenuated RF ablation zone (asterisk) along right hepatic vein (arrowhead), which sufficiently covers index tumor, as well as intact right hepatic vein. RF = radiofrequency, US = ultrasound

Mentions: "Parallel" targeting is a method in which a needle electrode is inserted near a large vessel's lumen parallel to the vessel wall in order to enlarge the contact surface between the ablation zone and the vessel, which may lead to a wider ablation zone (Fig. 7) (6). Parallel targeting along the large vessel may reduce the heat-sink effect and, in turn, produce the confluent shape of the ablation zone. Indeed, in order to overcome the heat-sink effect, an electrode needs to be positioned as close as possible to the large vessels that are in contact with the tumor (33). However, it might be impractical in cases when the tumor encases a large vessel or is adjacent to multiple large vessels.


Ultrasound-Guided Percutaneous Radiofrequency Ablation of Liver Tumors: How We Do It Safely and Completely.

Kim JW, Shin SS, Heo SH, Hong JH, Lim HS, Seon HJ, Hur YH, Park CH, Jeong YY, Kang HK - Korean J Radiol (2015)

RF ablation using parallel targeting along large vessel in 50-year-old man.A. Gadoxetic acid-enhanced axial hepatobiliary-phase T1-weighted image shows metastasis (arrow) from rectal cancer in segment 7 abutting right hepatic vein (arrowhead). B. Intercostal US image depicts hypoechoic metastasis (arrowhead) abutting right hepatic vein (arrow), which can potentially cause heat-sink effect during RF ablation. C. Intercostal US image during procedure demonstrates needle (arrow) in parallel to right hepatic vein (arrowhead) in order to enlarge contact surface between ablation zone and vessel. D. Immediate follow-up contrast-enhanced CT image shows elongated low-attenuated RF ablation zone (asterisk) along right hepatic vein (arrowhead), which sufficiently covers index tumor, as well as intact right hepatic vein. RF = radiofrequency, US = ultrasound
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4644743&req=5

Figure 7: RF ablation using parallel targeting along large vessel in 50-year-old man.A. Gadoxetic acid-enhanced axial hepatobiliary-phase T1-weighted image shows metastasis (arrow) from rectal cancer in segment 7 abutting right hepatic vein (arrowhead). B. Intercostal US image depicts hypoechoic metastasis (arrowhead) abutting right hepatic vein (arrow), which can potentially cause heat-sink effect during RF ablation. C. Intercostal US image during procedure demonstrates needle (arrow) in parallel to right hepatic vein (arrowhead) in order to enlarge contact surface between ablation zone and vessel. D. Immediate follow-up contrast-enhanced CT image shows elongated low-attenuated RF ablation zone (asterisk) along right hepatic vein (arrowhead), which sufficiently covers index tumor, as well as intact right hepatic vein. RF = radiofrequency, US = ultrasound
Mentions: "Parallel" targeting is a method in which a needle electrode is inserted near a large vessel's lumen parallel to the vessel wall in order to enlarge the contact surface between the ablation zone and the vessel, which may lead to a wider ablation zone (Fig. 7) (6). Parallel targeting along the large vessel may reduce the heat-sink effect and, in turn, produce the confluent shape of the ablation zone. Indeed, in order to overcome the heat-sink effect, an electrode needs to be positioned as close as possible to the large vessels that are in contact with the tumor (33). However, it might be impractical in cases when the tumor encases a large vessel or is adjacent to multiple large vessels.

Bottom Line: Although RF ablation is a safe and effective technique for the treatment of liver tumors, the outcome of treatment can be closely related to the location and shape of the tumors.Thus, a number of strategies have been developed to overcome these challenges, which include artificial ascites, needle track ablation, fusion imaging guidance, parallel targeting, bypass targeting, etc.This article offers technical strategies that can be used to effectively perform RF ablation as well as to minimize possible complications related to the procedure with representative cases and schematic illustrations.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Chonnam National University Medical School, Gwangju 61469, Korea.

ABSTRACT
Ultrasound-guided percutaneous radiofrequency (RF) ablation has become one of the most promising local cancer therapies for both resectable and nonresectable hepatic tumors. Although RF ablation is a safe and effective technique for the treatment of liver tumors, the outcome of treatment can be closely related to the location and shape of the tumors. There may be difficulties with RF ablation of tumors that are adjacent to large vessels or extrahepatic heat-vulnerable organs and tumors in the caudate lobe, possibly resulting in major complications or treatment failure. Thus, a number of strategies have been developed to overcome these challenges, which include artificial ascites, needle track ablation, fusion imaging guidance, parallel targeting, bypass targeting, etc. Operators need to use the right strategy in the right situation to avoid the possibility of complications and incomplete thermal tissue destruction; with the right strategy, RF ablation can be performed successfully, even for hepatic tumors in high-risk locations. This article offers technical strategies that can be used to effectively perform RF ablation as well as to minimize possible complications related to the procedure with representative cases and schematic illustrations.

No MeSH data available.


Related in: MedlinePlus