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Abstract No. 335: CT Imaging of Ablation Zones after Radiofrequency Ablation (RFA) of Kidney Tumors
MRI, the lesions were best visualized in T1W-VIBE or post-contrast and GRE sequences. DWI/ADC showed restricted diffusion in the lesions. A size difference of 1.4 ⫾ 4.5 mm (p⫽0.335) was found between MR/CT and gross measurement. H&E and Von Kossa staining showed complete cell death with a sharply demarcated margin between the ablated and non-ablated zone. Bile ducts and vessels were completely preserved. Focal hepatocellular regeneration was found in as early as 7 days post-IE. Areas of complete cell death stained nearly 100% with apoptotic markers (TUNEL, BCL-2, Caspase-3). Complete preservation of vessels were seen on vWf and VEGFR. No complications were noted peri- or post-procedure. CONCLUSION: 1. With real-time monitoring and wellcontrolled focused cell death of the target tissue, irreversible electroporation can be a novel and effective ablative method in hepatic tumor. 2. MRI, CT or US can be efficiently used for monitoring and characterization of IE ablated area perior immediately post-procedure.
Abstract No. 334 Safety and Therapeutic Effect of RFA Combined with TAE in Rabbit VX2 Liver Tumors. S. Li, R. Ni, L. Chen; First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China PURPOSE: To investigate safety and efficacy of radiofrequency ablation (RFA) combined with transcatheter artery embolization (TAE) on treatment of VX2 liver tumor of rabbit model. MATERIALS AND METHODS: Thirty six rabbits with implanted VX2 liver tumors were divided into 4 groups randomly. Group 1 served as control and received RFA only (n⫽9). Group 2, 3, and 4 received TAE and RFA (n⫽9 in each group). RFA was performed in day 1, 4, 7 after TAE respectively in study groups. Hepatic artery was embolized with lipiodol alone. Liver (ALT) and kidney (UREA) function of rabbit model were tested before procedure, 1, 4, and 7days after procedure respectively. 2, 2, and 5 rabbits were sacrificed for tumor harvest 1, 4, 7 days after RFA or TAE⫹RFA respectively. Maximal diameter of coagulation necrosis were recorded 7 days after study. Macroscopic and microscopic studies were also performed 1, 4, and 7days after.
CONCLUSION: RFA of VX2 liver tumor combined with TAE could evidently enlarge necrotic zone and may produce complete necrosis. However, RFA combined with TAE may impair liver function significantly when RFA
Abstract No. 335 CT Imaging of Ablation Zones after Radiofrequency Ablation (RFA) of Kidney Tumors. P.P. Sarlieve, J.R. Kachura; Toronto General Hospital and Mount Sinai Hospital, Toronto, ON, Canada PURPOSE: To determine the imaging features of ablation zones on triphasic CT scanning following RFA of kidney tumors. MATERIALS AND METHODS: All patients with kidney tumors treated with RFA at Toronto General Hospital and Mount Sinai Hospital since 2004, whose imaging follow-up consisted of triphasic CT scanning, were analyzed. Tumor pathology and size were noted. Typical CT follow-up was performed one month post-ablation and every 4-6 months thereafter. CT features evaluated included ablation zone size, attenuation, enhancement, and ancillary findings such as halo sign in perinephric fat. RESULTS: The patient cohort consisted of 33 patients (27 M, 6 F) with mean age 61 years (range 45-82). 37 tumors were treated, all using multi-tined LeVeen electrodes: 29 patients had a solitary tumor, whereas 4 patients had two tumors ablated each. Mean maximum tumor diameter was 2.3 cm (range 1.1-4.2). Pathological confirmation was obtained for 27 tumors (73%): there were 24 renal cell carcinomas and 3 oncocytic neoplasms. Mean CT imaging follow-up was 13 months (range 0.3-43). Ablation zone diameter was 10% larger than tumor diameter, on average, on the first follow-up CT, and then decreased to 7% smaller than the original tumor at 10 months and 19% smaller at 27 months post-ablation. Excluding 3 tumors containing calcifications, mean ablation zone attenuation was 40 ⫾ 15 Hounsfield Units (HU) at initial follow-up, and 27 ⫾ 7 HU at 33 months. One patient had obvious enhancing residual tumor tissue at initial follow-up which was successfully ablated with a second procedure. Another patient developed an enhancing nodule at the edge of the ablation zone at 35 months which was found to be chronic inflammation and fat necrosis on pathology. The halo sign, consisting of curvilinear soft tissue attenuation in perinephric fat, was noted around 16 ablation zones (43%), first identifed at a mean of 11 months post-ablation (range 5-13).
POSTER SESSIONS
RESULTS: There were seven rabbits died: 2 in group 1, 3 in group 2, 2 in group 3. All deaths happened in 24 hours after procedures. Value of ALT was elevated with worst seen in group 2 (385.0 ⫾ 213.1IU/L), and mildest in group 1 (P ⬍ 0.05). ALT started to improve 4 days after. In group 1, ALT returned back close to baseline after 7 days, which was significantly better than that seen in study groups. ALT value worsening was significant between group 3 and group 1(p ⬍ 0.05), but it was not significant between group 4 and group 1(p ⬎ 0.05). There were no significant changes in UREA value in all groups (p ⬎ 0.05). Ablated zone was significantly larger in all therapeutic groups than that in group 1 (p ⬍ 0.01), but there were no differences among study groups (p ⬎ 0.05).
performed within 4 days after TAE. Liver function impairment becomes less significant if RFA done 7 days after TAE. There was no obvious impact on renal function of in all groups.
CONCLUSION: After RFA of kidney tumors, ablation zones are initially larger than the treated tumors and then gradually decrease in size. The halo sign is a common delayed finding in perinephric fat post-ablation. Enhancing tissue related to the ablation zone may correspond to a non-malignant phenomenon. Abstract No. 336 Injection Techniques for Thermochemical Ablation. B.C. Smith, L.A. Freeman, B. Anwer, T.L. Brix, E.N.K. Cressman; University of Minnesota Medical School, Minneapolis, MN PURPOSE: To evaluate injection techniques for thermochemical ablation in an ex-vivo pig liver model as a new method for tumor ablation. S123
Abstract No. 334 Safety and Therapeutic Effect of RFA Combined with TAE in Rabbit VX2 Liver Tumors. S. Li, R. Ni, L. Chen; First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China PURPOSE: To investigate safety and efficacy of radiofrequency ablation (RFA) combined with transcatheter artery embolization (TAE) on treatment of VX2 liver tumor of rabbit model. MATERIALS AND METHODS: Thirty six rabbits with implanted VX2 liver tumors were divided into 4 groups randomly. Group 1 served as control and received RFA only (n⫽9). Group 2, 3, and 4 received TAE and RFA (n⫽9 in each group). RFA was performed in day 1, 4, 7 after TAE respectively in study groups. Hepatic artery was embolized with lipiodol alone. Liver (ALT) and kidney (UREA) function of rabbit model were tested before procedure, 1, 4, and 7days after procedure respectively. 2, 2, and 5 rabbits were sacrificed for tumor harvest 1, 4, 7 days after RFA or TAE⫹RFA respectively. Maximal diameter of coagulation necrosis were recorded 7 days after study. Macroscopic and microscopic studies were also performed 1, 4, and 7days after.
CONCLUSION: RFA of VX2 liver tumor combined with TAE could evidently enlarge necrotic zone and may produce complete necrosis. However, RFA combined with TAE may impair liver function significantly when RFA
Abstract No. 335 CT Imaging of Ablation Zones after Radiofrequency Ablation (RFA) of Kidney Tumors. P.P. Sarlieve, J.R. Kachura; Toronto General Hospital and Mount Sinai Hospital, Toronto, ON, Canada PURPOSE: To determine the imaging features of ablation zones on triphasic CT scanning following RFA of kidney tumors. MATERIALS AND METHODS: All patients with kidney tumors treated with RFA at Toronto General Hospital and Mount Sinai Hospital since 2004, whose imaging follow-up consisted of triphasic CT scanning, were analyzed. Tumor pathology and size were noted. Typical CT follow-up was performed one month post-ablation and every 4-6 months thereafter. CT features evaluated included ablation zone size, attenuation, enhancement, and ancillary findings such as halo sign in perinephric fat. RESULTS: The patient cohort consisted of 33 patients (27 M, 6 F) with mean age 61 years (range 45-82). 37 tumors were treated, all using multi-tined LeVeen electrodes: 29 patients had a solitary tumor, whereas 4 patients had two tumors ablated each. Mean maximum tumor diameter was 2.3 cm (range 1.1-4.2). Pathological confirmation was obtained for 27 tumors (73%): there were 24 renal cell carcinomas and 3 oncocytic neoplasms. Mean CT imaging follow-up was 13 months (range 0.3-43). Ablation zone diameter was 10% larger than tumor diameter, on average, on the first follow-up CT, and then decreased to 7% smaller than the original tumor at 10 months and 19% smaller at 27 months post-ablation. Excluding 3 tumors containing calcifications, mean ablation zone attenuation was 40 ⫾ 15 Hounsfield Units (HU) at initial follow-up, and 27 ⫾ 7 HU at 33 months. One patient had obvious enhancing residual tumor tissue at initial follow-up which was successfully ablated with a second procedure. Another patient developed an enhancing nodule at the edge of the ablation zone at 35 months which was found to be chronic inflammation and fat necrosis on pathology. The halo sign, consisting of curvilinear soft tissue attenuation in perinephric fat, was noted around 16 ablation zones (43%), first identifed at a mean of 11 months post-ablation (range 5-13).
POSTER SESSIONS
RESULTS: There were seven rabbits died: 2 in group 1, 3 in group 2, 2 in group 3. All deaths happened in 24 hours after procedures. Value of ALT was elevated with worst seen in group 2 (385.0 ⫾ 213.1IU/L), and mildest in group 1 (P ⬍ 0.05). ALT started to improve 4 days after. In group 1, ALT returned back close to baseline after 7 days, which was significantly better than that seen in study groups. ALT value worsening was significant between group 3 and group 1(p ⬍ 0.05), but it was not significant between group 4 and group 1(p ⬎ 0.05). There were no significant changes in UREA value in all groups (p ⬎ 0.05). Ablated zone was significantly larger in all therapeutic groups than that in group 1 (p ⬍ 0.01), but there were no differences among study groups (p ⬎ 0.05).
performed within 4 days after TAE. Liver function impairment becomes less significant if RFA done 7 days after TAE. There was no obvious impact on renal function of in all groups.
CONCLUSION: After RFA of kidney tumors, ablation zones are initially larger than the treated tumors and then gradually decrease in size. The halo sign is a common delayed finding in perinephric fat post-ablation. Enhancing tissue related to the ablation zone may correspond to a non-malignant phenomenon. Abstract No. 336 Injection Techniques for Thermochemical Ablation. B.C. Smith, L.A. Freeman, B. Anwer, T.L. Brix, E.N.K. Cressman; University of Minnesota Medical School, Minneapolis, MN PURPOSE: To evaluate injection techniques for thermochemical ablation in an ex-vivo pig liver model as a new method for tumor ablation. S123