Radiofrequency Ablation of the Liver
Current Status
John P. McGahan1 and
Gerald D. Dodd, III2
1
Department of Radiology, University of California, Davis Medical Center, 4860
Y St., Ste. 3100, Sacramento, CA 95817.
2
Department of Radiology, University of Texas Health Science Center at San
Antonio, 7703 Floyd Curl Dr., San Antonio, TX 78229-3900.
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Fig. 1A. —Original needle design. Photograph of original needle design
shows standard stock needle that is insulated (arrow) to distal tip.
Needle tip is not insulated.
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Fig. 1B. —Original needle design. Drawing shows theoretic lesion that
would be produced if noninsulated needle tip were used during monopolar
radiofrequency electrocautery. (Reprinted with permission from
[75])
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Fig. 2A. —In vivo sonographic and histologic correlation for
radiofrequency coagulation of swine liver. Sonogram of monopolar
radiofrequency lesion shows hyperechoic regions surrounded by hypoechoic rim
(arrow).
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Fig. 2B. —In vivo sonographic and histologic correlation for
radiofrequency coagulation of swine liver. Photograph of in vivo liver reveals
central area of charred tissue (1) surrounded by coagulative necrosis (2) and
hyperemic rim (arrow, 3). L = healthy liver. (Reprinted with
permission from [28])
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Fig. 3A. —Photographs of radiofrequency needle designs. Prongs protrude
in "Christmas tree" configuration from tip of needle manufactured
by RITA Medical Systems, Mountain View, CA.
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Fig. 3B. —Photographs of radiofrequency needle designs. Ten prongs
protrude in umbrella configuration from tip of needle manufactured by
Radiotherapeutics, Mountain View, CA.
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Fig. 3C. —Photographs of radiofrequency needle designs. Single
(solid arrow) and clustered (open arrow) cooled-tip needles
manufactured by Radionics, Burlington, MA.
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Fig. 4. —Photograph shows clustered cooled-tip needles placed
percutaneously into liver of patient using thimble guide (arrow) that
keeps needles in correct orientation during placement.
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Fig. 5A. —62-year-old man with metastases to liver from colon cancer.
Both preoperative CT scan (not shown) and sonogram show only a single large
metastasis in right lobe of liver (arrow) that was scheduled for
operative resection.
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Fig. 5B. —62-year-old man with metastases to liver from colon cancer.
At surgery, intraoperative sonography revealed several 4-mm metastases
scattered throughout liver (arrow). Resection was not performed.
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Fig. 6. —58-year-old woman with multiple metastases to liver from
colon cancer. Photograph shows intraoperative placement of radiofrequency
needle into liver (arrow).
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Fig. 7A. —76-year-old man with colon cancer and metastases to liver.
Sonogram shows guide for placement of needle into isolated hyperechoic colon
metastasis (arrow).
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Fig. 7B. —76-year-old man with colon cancer and metastases to liver. CT
scan shows deployed prongs (arrow) in lesion.
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Fig. 8. —Sonographic artifact seen in swine liver. Radiofrequency
ablation causes formation of microbubbles in liver. Margin near ablation
becomes echogenic (solid arrow) and produces distal acoustic
shadowing (open arrow). Echogenic response prevents visualization of
deeper anatomy.
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Fig. 9A. —64-year-old man with hepatitis C and hepatocellular carcinoma
(HCC). CT scan shows 1.5-cm enhancing lesion (arrow) that was
biopsy-proven HCC. Patient also had small amount of ascitic fluid surrounding
liver.
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Fig. 9B. —64-year-old man with hepatitis C and hepatocellular carcinoma
(HCC). Cooled-trip radiofrequency needle placed via freehand technique
directly into hypoechoic HCC lesion (arrow).
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Fig. 9C. —64-year-old man with hepatitis C and hepatocellular carcinoma
(HCC). Immediately after one radiofrequency treatment, echogenic microbubbles
are present in area of treatment (arrow).
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Fig. 9D. —64-year-old man with hepatitis C and hepatocellular carcinoma
(HCC). Echogenic response has diminished after approximately 10 min, and
well-demarcated lesion measuring 2.8 x 3.8 cm with hyperechoic rim is
identified in location of HCC.
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Fig. 10A. —Artist's rendition of ablation schemes. Solitary ablation
completely envelops small tumor and circumferential rim of healthy liver.
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Fig. 10B. —Artist's rendition of ablation schemes. Six optimally placed
overlapping spheres produce composite spherical thermal injury with diameter
equal to 1.25 times diameter of a single ablation sphere.
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Fig. 10C. —Artist's rendition of ablation schemes. Overlapping thermal
cylinders is effective way to treat large tumors. Each cylinder is created by
overlapping serial ablations by 50% along a single needle path. Adjacent
cylinders are overlapped by 50%.
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Fig. 11A. —58-year-old man with hepatocellular carcinoma. Arterial phase
CT scan of dome of right lobe of liver before ablation shows untreated
solitary hypervascular tumor.
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Fig. 11B. —58-year-old man with hepatocellular carcinoma. Arterial phase
CT scan immediately after ablation shows normal hyperemic rim
(arrows) around ablated tumor. Hyperemic rim may prevent accurate
assessment of completeness of ablation.
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Fig. 12A. —67-year-old man with two metastases from colon cancer. CT
scan shows two well-localized metastases (1, 2) in right lobe of liver.
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Fig. 12B. —67-year-old man with two metastases from colon cancer.
Three-month follow-up CT scan after radiofrequency ablation shows complete
ablation of tumors. Percutaneous radiofrequency approach was used for
treatment of the more lateral lesion. However, because of overlying bowel and
proximity to gallbladder, open radiofrequency ablation was used for the more
medial lesion.
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Fig. 13A. —46-year-old man with metastatic colon cancer. CT scan before
treatment shows 3-cm metastasis (arrow) in posterior right lobe of
liver.
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Fig. 13B. —46-year-old man with metastatic colon cancer. CT scan
immediately after ablation shows thermal injury (arrow) at site of
treated tumor and no definite evidence of residual tumor.
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Fig. 13C. —46-year-old man with metastatic colon cancer. Follow-up CT
scan at 3 months after ablation shows recurrent tumor (arrow) at
margin of ablated tumor.
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Fig. 13D. —46-year-old man with metastatic colon cancer. CT scan
immediately after reablation shows enlarged thermal injury (arrow) at
site of treated tumor recurrence and no definite evidence of residual
tumor.
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Copyright © 2001 by the American Roentgen Ray Society.
