PURPOSE: To use radiologic-histopathologic correlation in an animal model to distinguish normal postoperative findings from evidence of residual tumor after cryoablation of malignant hepatic tumors. MATERIALS AND METHODS: Hepatic cryoablation was performed in 12 rabbits with VX2 tumors and in two healthy rabbits. Nonenhanced and dynamic contrast material-enhanced computed tomography (CT) and magnetic resonance (MR) imaging and power and color Doppler flow ultrasonography (US) were performed 7-8 days after cryoablation. Histopathologic findings were correlated with imaging findings. RESULTS: Twenty tumors of 5-20 mm (mean, 10 mm) and seven areas of normal liver were treated with cryolesions of 11-21 mm (mean, 15 mm). All cryolesions exhibited arterial phase rim enhancement at CT and MR imaging, and 13 (57%) of 23 lesions demonstrated peripheral flow at US because of granulation tissue. There was macroscopic recurrence in 15 (75%) of 20 treated tumors; 14 (93%) appeared as peripheral nodularity with low-grade enhancement. Necrotic tissue did not enhance. Intact vessels extended up to 6 mm inside cryolesion margins and caused focal internal enhancement and Doppler flow. Areas of high signal intensity on T2-weighted MR images correlated with liquefaction necrosis, granulation tissue, and tumor. CONCLUSION: In this animal model, recurrent tumor typically appeared as focal nodules at the cryolesion periphery. Rim and central foci of enhancement, Doppler flow, and increased signal intensity on T2-weighted MR images can be normal findings after hepatic cryoablation.
PURPOSE: To use radiologic-histopathologic correlation in an animal model to distinguish normal postoperative findings from evidence of residual tumor after cryoablation of malignant hepatic tumors. MATERIALS AND METHODS: Hepatic cryoablation was performed in 12 rabbits with VX2 tumors and in two healthy rabbits. Nonenhanced and dynamic contrast material-enhanced computed tomography (CT) and magnetic resonance (MR) imaging and power and color Doppler flow ultrasonography (US) were performed 7-8 days after cryoablation. Histopathologic findings were correlated with imaging findings. RESULTS: Twenty tumors of 5-20 mm (mean, 10 mm) and seven areas of normal liver were treated with cryolesions of 11-21 mm (mean, 15 mm). All cryolesions exhibited arterial phase rim enhancement at CT and MR imaging, and 13 (57%) of 23 lesions demonstrated peripheral flow at US because of granulation tissue. There was macroscopic recurrence in 15 (75%) of 20 treated tumors; 14 (93%) appeared as peripheral nodularity with low-grade enhancement. Necrotic tissue did not enhance. Intact vessels extended up to 6 mm inside cryolesion margins and caused focal internal enhancement and Doppler flow. Areas of high signal intensity on T2-weighted MR images correlated with liquefaction necrosis, granulation tissue, and tumor. CONCLUSION: In this animal model, recurrent tumor typically appeared as focal nodules at the cryolesion periphery. Rim and central foci of enhancement, Doppler flow, and increased signal intensity on T2-weighted MR images can be normal findings after hepatic cryoablation.
Authors: Sumeet Virmani; Kathleen R Harris; Barbara Szolc-Kowalska; Tatjana Paunesku; Gayle E Woloschak; Fred T Lee; Robert J Lewandowski; Kent T Sato; Robert K Ryu; Riad Salem; Andrew C Larson; Reed A Omary Journal: J Vasc Interv Radiol Date: 2008-04-18 Impact factor: 3.464