HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Shock, S. A. Articles by Lee, F. T. Search for Related Content PubMed PubMed Citation Articles by Shock, S. A. Articles by Lee, F. T., Jr

Microwave Ablation with Loop Antenna: In Vivo Porcine Liver Model¹

¹ From the Departments of Radiology (S.A.S., L.A.S., T.C.W., F.T.L.), Surgery (K.M., A.S.W., D.M.M.), Pathology and Laboratory Medicine (T.F.W.), and Biostatistics (J.P.F.), University of Wisconsin Hospitals and Clinics, E3/311 Clinical Science Center, 600 Highland Ave, Madison, WI 53792. Received October 18, 2002; revision requested January 7, 2003; final revision received May 13; accepted August 14. Supported in part by Vivant Medical, Mountain View, Calif. Address correspondence to F.T.L. (e-mail: ftlee@wisc.edu).

View larger version (67K): [in a new window]   Figure 1a. (a) Prototype single-loop microwave antenna used in this study. Microwave probe (arrow) is placed in tissue, and loop (arrowhead) is deployed by using electrocautery energy to cut through tissue, which minimizes distortion of loop. (b) Prototype parallel microwave antennas. Probes are fixed 1.6 cm apart in a plastic handle in parallel configuration. Each probe is equivalent to the single probe in a. (c) Prototype orthogonal microwave antennas. Similar to the parallel configuration in b, the probes are fixed in a plastic handle, but in the orthogonal configuration, the loops are canted 45° toward each other. With this configuration, targeted tissue is encircled with both loops.

View larger version (69K): [in a new window]   Figure 1b. (a) Prototype single-loop microwave antenna used in this study. Microwave probe (arrow) is placed in tissue, and loop (arrowhead) is deployed by using electrocautery energy to cut through tissue, which minimizes distortion of loop. (b) Prototype parallel microwave antennas. Probes are fixed 1.6 cm apart in a plastic handle in parallel configuration. Each probe is equivalent to the single probe in a. (c) Prototype orthogonal microwave antennas. Similar to the parallel configuration in b, the probes are fixed in a plastic handle, but in the orthogonal configuration, the loops are canted 45° toward each other. With this configuration, targeted tissue is encircled with both loops.

View larger version (102K): [in a new window]   Figure 1c. (a) Prototype single-loop microwave antenna used in this study. Microwave probe (arrow) is placed in tissue, and loop (arrowhead) is deployed by using electrocautery energy to cut through tissue, which minimizes distortion of loop. (b) Prototype parallel microwave antennas. Probes are fixed 1.6 cm apart in a plastic handle in parallel configuration. Each probe is equivalent to the single probe in a. (c) Prototype orthogonal microwave antennas. Similar to the parallel configuration in b, the probes are fixed in a plastic handle, but in the orthogonal configuration, the loops are canted 45° toward each other. With this configuration, targeted tissue is encircled with both loops.

View larger version (98K): [in a new window]   Figure 2a. (a) Representative slice from single lesion demonstrates nonspherical crescent-shaped lesion treated with microwave ablation. (b) Representative slice from parallel lesion demonstrates slightly ovoid shape. Note that vessels (arrows) near the lesion edge create indentations in the treated lesion. (c) Representative slice from orthogonal lesion is more spherical than are single or parallel lesions. Note partially thrombosed vessel (arrow) near edge of lesion.

View larger version (148K): [in a new window]   Figure 2b. (a) Representative slice from single lesion demonstrates nonspherical crescent-shaped lesion treated with microwave ablation. (b) Representative slice from parallel lesion demonstrates slightly ovoid shape. Note that vessels (arrows) near the lesion edge create indentations in the treated lesion. (c) Representative slice from orthogonal lesion is more spherical than are single or parallel lesions. Note partially thrombosed vessel (arrow) near edge of lesion.

View larger version (158K): [in a new window]   Figure 2c. (a) Representative slice from single lesion demonstrates nonspherical crescent-shaped lesion treated with microwave ablation. (b) Representative slice from parallel lesion demonstrates slightly ovoid shape. Note that vessels (arrows) near the lesion edge create indentations in the treated lesion. (c) Representative slice from orthogonal lesion is more spherical than are single or parallel lesions. Note partially thrombosed vessel (arrow) near edge of lesion.

View larger version (138K): [in a new window]   Figure 3a. (a) Parallel lesion with central viable tissue () caused by formation of noncontiguous lesion. (b) Orthogonal lesion with tissue necrosis throughout. Note large vessel (arrow) that creates an indentation on lesion periphery.

View larger version (150K): [in a new window]   Figure 3b. (a) Parallel lesion with central viable tissue () caused by formation of noncontiguous lesion. (b) Orthogonal lesion with tissue necrosis throughout. Note large vessel (arrow) that creates an indentation on lesion periphery.

View larger version (72K): [in a new window]   Figure 4. Consecutive slices from parallel lesion. Left: Unstained. Right: TTC stained. Note 4-mm vessel (arrows) in center of lesion. TTC-stained slice demonstrates dark blue-purple viable perivascular tissue that was not apparent on unstained slice.

View larger version (126K): [in a new window]   Figure 5. Orthogonal TTC-stained lesion. Lighter area of tissue necrosis is outlined by viable tissue, which is stained dark blue purple. Note absence of stain in center of lesion, even in perivascular areas (arrows), which indicates complete necrosis throughout the lesion (compare with Fig 4).

View larger version (172K): [in a new window]   Figure 6a. (a) Photomicrograph from peripheral (zone 1) lesion treated with microwave ablation. Moderate amount of hepatic damage is present in this zone. Note intact liver cell plates, visible cell borders, and normal nuclear morphology. However, in contrast to normal pig liver, sinusoids are congested with intact erythrocytes (white arrow), and sinusoidal lining cells (Kupffer cells) are separated from hepatocytes (black arrow). (Hematoxylin-eosin stain; original magnification, x200.) (b) Photomicrograph from intermediate (zone 2) lesion treated with microwave ablation. No viable hepatocytes are present in this zone. Hepatocytes are swollen as a result of loss of cell walls. Sinusoids are filled with debris from destroyed red blood cells. (Hematoxylin-eosin stain; original magnification, x200.) (c) Photomicrograph from central (zone 3) lesion treated with microwave ablation. Very severe hepatic damage is present in this zone, and no viable hepatocytes are present. Liver cell plates are grossly distorted. Note adjacent zone 2 tissue (arrow) and a vein () filled with red cell ghosts. (Hematoxylin-eosin stain; original magnification, x20.)

View larger version (153K): [in a new window]   Figure 6b. (a) Photomicrograph from peripheral (zone 1) lesion treated with microwave ablation. Moderate amount of hepatic damage is present in this zone. Note intact liver cell plates, visible cell borders, and normal nuclear morphology. However, in contrast to normal pig liver, sinusoids are congested with intact erythrocytes (white arrow), and sinusoidal lining cells (Kupffer cells) are separated from hepatocytes (black arrow). (Hematoxylin-eosin stain; original magnification, x200.) (b) Photomicrograph from intermediate (zone 2) lesion treated with microwave ablation. No viable hepatocytes are present in this zone. Hepatocytes are swollen as a result of loss of cell walls. Sinusoids are filled with debris from destroyed red blood cells. (Hematoxylin-eosin stain; original magnification, x200.) (c) Photomicrograph from central (zone 3) lesion treated with microwave ablation. Very severe hepatic damage is present in this zone, and no viable hepatocytes are present. Liver cell plates are grossly distorted. Note adjacent zone 2 tissue (arrow) and a vein () filled with red cell ghosts. (Hematoxylin-eosin stain; original magnification, x20.)

View larger version (177K): [in a new window]   Figure 6c. (a) Photomicrograph from peripheral (zone 1) lesion treated with microwave ablation. Moderate amount of hepatic damage is present in this zone. Note intact liver cell plates, visible cell borders, and normal nuclear morphology. However, in contrast to normal pig liver, sinusoids are congested with intact erythrocytes (white arrow), and sinusoidal lining cells (Kupffer cells) are separated from hepatocytes (black arrow). (Hematoxylin-eosin stain; original magnification, x200.) (b) Photomicrograph from intermediate (zone 2) lesion treated with microwave ablation. No viable hepatocytes are present in this zone. Hepatocytes are swollen as a result of loss of cell walls. Sinusoids are filled with debris from destroyed red blood cells. (Hematoxylin-eosin stain; original magnification, x200.) (c) Photomicrograph from central (zone 3) lesion treated with microwave ablation. Very severe hepatic damage is present in this zone, and no viable hepatocytes are present. Liver cell plates are grossly distorted. Note adjacent zone 2 tissue (arrow) and a vein () filled with red cell ghosts. (Hematoxylin-eosin stain; original magnification, x20.)