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

This Article Figures Only Full Text Full Text (PDF) All Versions of this Article: jnumed.107.042846v1 48/11/1836    most recent Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Related articles in JNM 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 Google Scholar Google Scholar Articles by Vogt, F. M. Articles by Kuehl, H. Search for Related Content PubMed PubMed Citation Articles by Vogt, F. M. Articles by Kuehl, H.

Morphologic and Functional Changes in Nontumorous Liver Tissue After Radiofrequency Ablation in an In Vivo Model: Comparison of ¹⁸F-FDG PET/CT, MRI, Ultrasound, and CT

¹ Department of Diagnostic and Interventional Radiology and Neuroradiology, University Duisburg–Essen, Essen, Germany; ² Department of Nuclear Medicine, University Duisburg–Essen, Essen, Germany; and ³ Department of Pathology, University Cologne, Cologne, Germany

Correspondence: For correspondence or reprints contact: Florian M. Vogt, MD, Department of Diagnostic and Interventional Radiology and Neuroradiology, University of Duisburg–Essen, Hufelandstrasse 55, D-45122 Essen, Germany. E-mail: florian.vogt{at}uni-essen.de

Rimlike contrast enhancement on morphologic imaging and increased tracer uptake on ¹⁸F-FDG PET in the periphery of the necrosis can hamper differentiation of residual tumor from regenerative tissue after radiofrequency ablation of liver lesions. This study used MRI, CT, ultrasound, and ¹⁸F-FDG PET/CT to assess the typical appearance of lesions in nontumorous animal liver tissue after radiofrequency ablation. Methods: Lesions were created by radiofrequency ablation of normal liver parenchyma in 21 minipigs. Follow-up was performed by 3 contrast-enhanced morphologic modalities—MRI, CT, and ultrasound—and by ¹⁸F-FDG PET/CT immediately, 3 and 10 d, and 1, 2, 3, and 6 mo after radiofrequency ablation. Images were evaluated qualitatively for areas of increased enhancement and regions of elevated tracer uptake. Furthermore, all images were assessed quantitatively by determination of ratios comparing enhancement/tracer uptake in the periphery of the necrosis with enhancement/tracer uptake in normal liver parenchyma. Imaging findings were compared with histopathology findings. Results: Immediately after radiofrequency ablation, no increase in ¹⁸F-FDG uptake was visible, whereas elevated enhancement was noticed in the periphery of the necrosis on all morphologic imaging procedures. At further follow-up, an area of rimlike increase in ¹⁸F-FDG uptake surrounding the necrosis was detected on PET/CT. The rimlike pattern of increased enhancement in the arterial phase was present for all liver lesions on CT, MRI, and ultrasound, especially between day 3 and month 1 after the radiofrequency ablation. Both elevated glucose metabolism and enhancement persisted for 6 mo postinterventionally. Histologic examination showed a hemorrhagic border converting into a regeneration capsule. Conclusion: If performed immediately after radiofrequency ablation, ¹⁸F-FDG PET/CT probably has benefits over those of morphologic imaging procedures when assessing liver tissue for residual tumor. Later follow-up may be hampered by visualization of peripheral hyperperfusion and tissue regeneration. Further studies on a patient population are essential.

Key Words: minimally invasive technique • tissue necrosis • periablational region • peripheral enhancement • tissue response

COPYRIGHT © 2007 by the Society of Nuclear Medicine, Inc.

Related articles in JNM:

This Month in JNM

JNM 2007 48: 11A-12A. [Full Text]