Radiofrequency Ablated Lesion in the Normal Porcine Lung: Long-Term Follow-Up with MRI and Pathology

Journal Article · Fri Apr 15 04:00:00 EDT 2005 · Cardiovascular and Interventional Radiology

DOI:https://doi.org/10.1007/S00270-004-0156-8· OSTI ID:21088124

Oyama, Yoshimasa; Nakamura, Kenji; Matsuoka, Toshiyuki; Toyoshima, Masami; Yamamoto, Akira; Okuma, Tomohisa ^[1]; Ikura, Yoshihiro; Ueda, Makiko ^[2]; Inoue, Yuichi ^[1]

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1. Osaka City University Graduate School of Medicine, Department of Radiology (Japan)
2. Osaka City University Graduate School of Medicine, Department of Pathology (Japan)

Purpose. To evaluate the effectiveness of magnetic resonance imaging (MRI) in reflecting histopathologic changes after radiofrequency ablation (RFA) to the lung and to assess accurately the extent of tissue necrosis for evaluating untreated lesions. Methods. Percutaneous RFA was performed on 72 lung regions in 12 pigs under computed tomographic guidance. After performing MRI, the animals were divided into three experimental phases: in the acute phase, 4 pigs were killed immediately after the procedure; in the subacute phase, 4 pigs were killed at 1 week; and in the chronic phases, 2 pigs were killed at 4 and 8 weeks after the procedure, respectively. MRI-histopathologic correlation was performed. Results. In the acute phase, the inner zone showed hypointensity on T2-weighted images and isointensity on T1-weighted images, with a lack of enhancement on contrast-enhanced T1-weighted images, representing early changes in coagulative necrosis on histopathologic examination. The outer zone showed hyperintensity on T2-weighted images and isointensity on T1-weighted images, with ring-like enhancement on contrast-enhanced T1-weighted images. The histopathologic section showed alveolar fluid collections and congestion. In the subacute phase the MR zone pattern was essentially similar to that of the acute phase, but the ablated lesion showed extensive coagulative necrosis with a fibrovascular rim on histopathologic examination. In the chronic phase, there was no change in the zone pattern on MRI. The lesions showed gradual resorption of coagulative necrosis. The area of coagulative necrosis correlated closely with the histopathologic size (p < 0.05). Conclusions. MRI effectively visualized the histopathologic changes after RFA and accurately determined the extent of the necrotic lesion. MRI is potentially a useful modality for evaluating therapeutic efficacy after RFA to the lung.

• OSTI ID: 21088124
• Journal Information: Cardiovascular and Interventional Radiology, Journal Name: Cardiovascular and Interventional Radiology Journal Issue: 3 Vol. 28; ISSN 0174-1551; ISSN CAIRDG
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
ABLATION
IMAGES
LUNGS
NECROSIS
NMR IMAGING
PATHOLOGY
RADIOWAVE RADIATION
RESONANCE IONIZATION MASS SPECTROSCOPY
SWINE