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Abstract No. 277: Interventional oncology: Overview of liver directed therapy
JVIR 䡲 Poster Sessions
S117
shown, demonstrating its ability to increase lesion conspicuity and guide probe placement. Enhancement patterns of primary and recurrent HCC and renal cell carcinomas will be presented. The importance of CEUS in detecting areas of recurrent disease in previous ablation zones and increasing operator confidence will be discussed. Conclusion and/or Teaching Points: CEUS can be used to provide real-time visualization of early stage HCC and small renal tumors in order to guide RFA. CEUS increases operator confidence during RFA, thereby reducing procedure time, and can be used to assess residual tumor at the time of ablation or at followup. It provides an alternative method of assessment to CECT and MRI, particularly in those patients with renal impairment.
Abstract No. 275 Prognositic factors after radiofrequency ablation for nonresectable colorectal cancer liver metastases A. Hamada, K. Yamakado, A. Nakatsuka, J. Uraki, M. Kashima, H. Takaki, T. Yamanaka, K. Takeda; Department of Radiology, Mie University School of Medicine, Tsu, Japan Purpose: To determine prognostic factors in patients with colorectal cancer liver metastases treated by radiofrequency (RF) ablation. Materials and Methods: Retrospective analysis was performed in 81 consecutive patients with nonresectable colorectal liver metastases. A total of 130 tumors were treated by 136 RF sessions. RF electrodes were placed under CT-fluoroscopic guidance under conscious sedation. Overall survivals were estimated using Kaplan-Meier method and prognostic factors were identified by multivariate analysis. Results: Thirty-five tumors (35/130, 27%) in 31 patients (31/ 81, 38%) developed local tumor progression at a mean period of 7.2 months after RF ablation during a median follow-up period of 24.7 months. The 1-, 3-, 5- and 7-year overall survival rates were 87%, 44%, 16% and 11%, respectively, with a median survival of 34.9 months. Extrahepatic disease (present/ absent), tumor size (⬍3cm/⬎3cm in diameter), and tumor number (single/multiple) were significantly independent prognostic factors. In 14 patients who had solitary tumor of 3cm or smaller in diameter without extrahepatic disease, the 1-, 3-, 5-year overall survival rates were 100%, 72%, and 41%, respectively, with a median survival of 59.2 months. Conclusion: RF ablation helps to prolong survival in selected patients with unresectable colorectal liver metastases.
Abstract No. 276
E.W. Lee1, D. Wong1, A. Perez1, S.V. Prikhodko2, C. Tran1, C.T. Loh1, S.T. Kee1; 1Div of Interventional Radiology, Department of Radiology, UCLA Medical Center, Los Angeles, CA; 2Department of Material Science and Engineering, UCLA, Los Angeles, CA Purpose: To demonstrate, evaluate and verify the existence of IRE ablation induced nanopores on the hepatocytes plasma membrane.
Educational Exhibit
Abstract No. 277
Interventional oncology: Overview of liver directed therapy C. Ahuja, M. Chadha, J.J. Critchfield, N. Malay; Radiology, Wayne State University/Detroit Medical Center, Detroit, MI Learning Objectives: Interventionally directed treatment of hepatic malignancy has been reviewed procedure-wise so as to ascertain patient selection for the most suitable treatment modality. Indications and contraindications of each procedure are clearly tabulated. Background: Update on various treatment modalities available for local liver directed treatment including local ablation and transarterial embolization. Clinical Findings/Procedure Details: Goal of Liver directed therapy. Methods of Liver directed treatment Local Ablation Alcohol ablation Radio frequency Ablation Microwave ablation Cryoablation Electroporation Transarterial embolization TACE (standard transarterial chemoembolization) Drug eluding beads Radioembolization Combined TACE and local ablation Techniques, advantages, limitations and complications of each treatment modality. Conclusion and/or Teaching Points: Interventional radiologists play a crucial role in management of liver malignancy. The
Poster Sessions
Electron microscopic (EM) demonstration and evaluation of irreversible electroporation (IRE)-induced nanopores on hepatocyte membranes: A preliminary data
Materials and Methods: Upon ARC approval, six New Zealand Rabbits underwent IRE ablation of liver and selected ablated liver tissues were harvested, fixed and air-dried according to the EM protocol. A scanning electron microscopy (SEM, Nova 230 NanoSEM with 80 pico amps and 10kV acceleration) was used to visualize and verify IRE created nanopores. A total of 15 ablated tissues (n⫽15) were evaluated using NIH image and ImageScope. Corresponding H&E evaluation was performed to verify IRE-induced cell death. Results: In all 15 IRE-ablated tissues, SEM was able to demonstrate numerous, well-circumscribed, round, and concave shaped pore defects disturbing the hepatocyte plasma membranes. These pores were not seen in normal liver. The size of the nanopores was from 80 to 430 nano meters (nm) with the greatest frequency of pores in the lower 300 nm range. This is notably different from the nanopores created by reversible electroporation (RE). Conclusion: 1) We have demonstrated that IRE induces irreversible nanopores on hepatocyte membranes using SEM. This study is the first scientific evaluation to demonstrate and validate IRE created nanopores which is the etiology of cell death caused by IRE ablation. 2) The pore diameters are significantly larger than nanopores created by RE suggesting larger pores prevent intrinsic lipidbilayer interactions from resealing the defects.
Poster Sessions 䡲 JVIR
S118
goal of these treatments vary from a bridge to transplantation, tumor shrinkage prior to surgical resection to palliative management. Based on the extent of tumor burden, various methods of liver directed treatment are available. Knowledge of techniques, limitations and complications of these treatment modalities is vital in treatment planning.
Educational Exhibit
Abstract No. 278
Transarterial radioembolization of liver tumors: Angiographic considerations C. Ahuja, J.J. Critchfield, M. Chadha, N. Malay; Radiology, Wayne State University/Detroit Medical Center, Detroit, MI Learning Objectives: Angiographic mapping of mesenteric arteries plays a pivotal role in therasphere treatment planning. 1. To understand the standard anatomy and normal variants of hepatic and mesenteric arterial system. 2. To identify non-hepatic branches arising from hepatic arteries. 3. To familiarize with different patterns of tumor perfusion. 4. To understand strategies used to prevent non-target embolization. Background: Importance of preprocedural planning for radioembolization based on angiographic findings. Standard anatomy and commonly seen variations of hepatic arterial anatomy. Clinical Findings/Procedure Details: 1) Identification of gastric arteries, cystic arteries, falciform arteries arising from hepatic arteries. 2) Gastroduodenal artery origin in relation to other hepatic arteries and its importance. 3) Phrenic artery as extrahepatic collateral blood suply to liver tumors. 4) Patterns of perfusion of hepatic lesions and principle of redistribution. Conclusion and/or Teaching Points: The mesenteric arterial arcade and hepatic arterial bed demonstrate a wide spectrum of variation. An understanding of arterial variants plays a key role in pre-procedural planning, catheterization and delivery of therapeutic agent. Altered regional hepatic perfusion mapping is required to optimize intervention; more so in the presence of hepatic malignancy. New liver directed therapies, such as radioembolization, mandate meticulous comprehension of normal and variant mesenteric arterial anatomy.
Abstract No. 279 Incidence and detection of dual blood supply to hepatocellular carcinoma located in watershed regions of segment IV and VIII during transarterial chemoembolization
Poster Sessions
M. Abdelmaksoud, G.L. Hwang, J.D. Louie, D.Y. Sze, N. Kothary; Interventional Radiology, Stanford University, Stanford, CA Purpose: Hepatocellular carcinoma (HCC) located in watershed regions of segments IV and VIII are known to have arterial supply from both the left and the right hepatic arteries. In this study we report the incidence and detection of dual hepatic supply in HCC during transarterial chemoembolization. Implication on management of these tumors is also reported. Materials and Methods: We retrospectively reviewed all angiographic images of patients undergoing transarterial chemoembolization for HCC from August 2008 to August 2009. Patients with tumors ⬍ 4 cm were selected for this data analysis. Digital subtraction angiography (DSA) and C-arm CT (CACT) images
were reviewed and we noted whether dual blood supply was recognized prospectively or on follow-up studies. Results: Of the 253 patients who underwent 352 chemoembolizations, 49 patients with 57 tumors located in watershed regions were included in the study (32 segment VIII, 25 segment IV). Of these, 13 tumors (22.8%) in 13 patients (26.5%) had dual blood supply. 9 (69.2%) were in segment IV and 4 (30.8%), in segment VIII (p⫽.036). Dual supply was identified prospectively in 7 (53.8%) tumors, while in 6 (46.2%) the presence of viable disease on follow-up resulted in additional treatment that identified dual supply. Conclusion: Tumors in watershed regions of the liver, especially in segment IV, have a high propensity for dual blood supply. Interrogation of both right and left hepatic arteries is essential to ensure complete treatment.
Abstract No. 280 Detection of small hepatocellular carcinoma during transarterial chemoembolization: Comparison between C-arm CT and digital subtraction angiography M. Abdelmaksoud, G.L. Hwang, J.D. Louie, L. Hofmann, D.Y. Sze, N. Kothary; Interventional Radiology, Stanford University, Stanford, CA Purpose: Small hepatocellular carcinomas (HCC) ⬍ 2 cm in diameter are often difficult to identify and localize by digital subtraction angiography (DSA) during transarterial chemoembolization. The purpose of our study was to compare C-arm CT (CACT) to DSA in its ability to identify small HCC, distinguish segmental localization and provide an anatomic roadmap for superselective transarterial chemoembolization. Materials and Methods: Two interventional radiologists retrospectively reviewed 262 transarterial chemoembolizations performed on 180 consecutive patients treated from January 2008 to August 2009. Patients with a maximum of 3 hypervascular tumors ⱕ 2 cm detected by preprocedural imaging (CT or MRI) were selected for the analysis. We examined 100 tumors in 65 patients who underwent 74 procedures. Proper or common hepatic arteriograms (DSA) in the antero-posterior and oblique projections, selective segmental hepatic arteriograms (DSA), and contrast medium enhanced CACT were reviewed for each patient. Diagnostic ability to identify and locate the tumors was compared between modalities. The number of acquisitions, radiation dose, and contrast medium used were also compared. Results: The sensitivities of non-selective DSA, selective DSA and CACT in identifying the tumors were 64%, 84% and 98%, respectively (P ⫽ 0.057). The mean number of DSA and CACT acquisitions in the study group was 6.6 and 1.5, respectively. Total volume of iodinated contrast used was 60.4 ml (30 –125ml), of which contrast enhanced CACT accounted for 20.7% (12.5 ml, range 3–30ml). Conclusion: CACT is more sensitive than DSA for identifying and localizing hypervascular HCC ⬍ 2 cm. An enhanced CACT may provide crucial or additional information not available by the corresponding DSA acquisitions in two projections. We propose CACT should be performed following catheterization of the common or proper hepatic artery in lieu of multiple DSA acquisitions. Although each CACT acquisition has the radiation exposure equivalent to two DSA acquisitions, the information provided by CACT would reduce the number of subsequent DSA acquisitions and subsequently the total radiation dose and volume of iodinated contrast used may all be decreased.
S117
shown, demonstrating its ability to increase lesion conspicuity and guide probe placement. Enhancement patterns of primary and recurrent HCC and renal cell carcinomas will be presented. The importance of CEUS in detecting areas of recurrent disease in previous ablation zones and increasing operator confidence will be discussed. Conclusion and/or Teaching Points: CEUS can be used to provide real-time visualization of early stage HCC and small renal tumors in order to guide RFA. CEUS increases operator confidence during RFA, thereby reducing procedure time, and can be used to assess residual tumor at the time of ablation or at followup. It provides an alternative method of assessment to CECT and MRI, particularly in those patients with renal impairment.
Abstract No. 275 Prognositic factors after radiofrequency ablation for nonresectable colorectal cancer liver metastases A. Hamada, K. Yamakado, A. Nakatsuka, J. Uraki, M. Kashima, H. Takaki, T. Yamanaka, K. Takeda; Department of Radiology, Mie University School of Medicine, Tsu, Japan Purpose: To determine prognostic factors in patients with colorectal cancer liver metastases treated by radiofrequency (RF) ablation. Materials and Methods: Retrospective analysis was performed in 81 consecutive patients with nonresectable colorectal liver metastases. A total of 130 tumors were treated by 136 RF sessions. RF electrodes were placed under CT-fluoroscopic guidance under conscious sedation. Overall survivals were estimated using Kaplan-Meier method and prognostic factors were identified by multivariate analysis. Results: Thirty-five tumors (35/130, 27%) in 31 patients (31/ 81, 38%) developed local tumor progression at a mean period of 7.2 months after RF ablation during a median follow-up period of 24.7 months. The 1-, 3-, 5- and 7-year overall survival rates were 87%, 44%, 16% and 11%, respectively, with a median survival of 34.9 months. Extrahepatic disease (present/ absent), tumor size (⬍3cm/⬎3cm in diameter), and tumor number (single/multiple) were significantly independent prognostic factors. In 14 patients who had solitary tumor of 3cm or smaller in diameter without extrahepatic disease, the 1-, 3-, 5-year overall survival rates were 100%, 72%, and 41%, respectively, with a median survival of 59.2 months. Conclusion: RF ablation helps to prolong survival in selected patients with unresectable colorectal liver metastases.
Abstract No. 276
E.W. Lee1, D. Wong1, A. Perez1, S.V. Prikhodko2, C. Tran1, C.T. Loh1, S.T. Kee1; 1Div of Interventional Radiology, Department of Radiology, UCLA Medical Center, Los Angeles, CA; 2Department of Material Science and Engineering, UCLA, Los Angeles, CA Purpose: To demonstrate, evaluate and verify the existence of IRE ablation induced nanopores on the hepatocytes plasma membrane.
Educational Exhibit
Abstract No. 277
Interventional oncology: Overview of liver directed therapy C. Ahuja, M. Chadha, J.J. Critchfield, N. Malay; Radiology, Wayne State University/Detroit Medical Center, Detroit, MI Learning Objectives: Interventionally directed treatment of hepatic malignancy has been reviewed procedure-wise so as to ascertain patient selection for the most suitable treatment modality. Indications and contraindications of each procedure are clearly tabulated. Background: Update on various treatment modalities available for local liver directed treatment including local ablation and transarterial embolization. Clinical Findings/Procedure Details: Goal of Liver directed therapy. Methods of Liver directed treatment Local Ablation Alcohol ablation Radio frequency Ablation Microwave ablation Cryoablation Electroporation Transarterial embolization TACE (standard transarterial chemoembolization) Drug eluding beads Radioembolization Combined TACE and local ablation Techniques, advantages, limitations and complications of each treatment modality. Conclusion and/or Teaching Points: Interventional radiologists play a crucial role in management of liver malignancy. The
Poster Sessions
Electron microscopic (EM) demonstration and evaluation of irreversible electroporation (IRE)-induced nanopores on hepatocyte membranes: A preliminary data
Materials and Methods: Upon ARC approval, six New Zealand Rabbits underwent IRE ablation of liver and selected ablated liver tissues were harvested, fixed and air-dried according to the EM protocol. A scanning electron microscopy (SEM, Nova 230 NanoSEM with 80 pico amps and 10kV acceleration) was used to visualize and verify IRE created nanopores. A total of 15 ablated tissues (n⫽15) were evaluated using NIH image and ImageScope. Corresponding H&E evaluation was performed to verify IRE-induced cell death. Results: In all 15 IRE-ablated tissues, SEM was able to demonstrate numerous, well-circumscribed, round, and concave shaped pore defects disturbing the hepatocyte plasma membranes. These pores were not seen in normal liver. The size of the nanopores was from 80 to 430 nano meters (nm) with the greatest frequency of pores in the lower 300 nm range. This is notably different from the nanopores created by reversible electroporation (RE). Conclusion: 1) We have demonstrated that IRE induces irreversible nanopores on hepatocyte membranes using SEM. This study is the first scientific evaluation to demonstrate and validate IRE created nanopores which is the etiology of cell death caused by IRE ablation. 2) The pore diameters are significantly larger than nanopores created by RE suggesting larger pores prevent intrinsic lipidbilayer interactions from resealing the defects.
Poster Sessions 䡲 JVIR
S118
goal of these treatments vary from a bridge to transplantation, tumor shrinkage prior to surgical resection to palliative management. Based on the extent of tumor burden, various methods of liver directed treatment are available. Knowledge of techniques, limitations and complications of these treatment modalities is vital in treatment planning.
Educational Exhibit
Abstract No. 278
Transarterial radioembolization of liver tumors: Angiographic considerations C. Ahuja, J.J. Critchfield, M. Chadha, N. Malay; Radiology, Wayne State University/Detroit Medical Center, Detroit, MI Learning Objectives: Angiographic mapping of mesenteric arteries plays a pivotal role in therasphere treatment planning. 1. To understand the standard anatomy and normal variants of hepatic and mesenteric arterial system. 2. To identify non-hepatic branches arising from hepatic arteries. 3. To familiarize with different patterns of tumor perfusion. 4. To understand strategies used to prevent non-target embolization. Background: Importance of preprocedural planning for radioembolization based on angiographic findings. Standard anatomy and commonly seen variations of hepatic arterial anatomy. Clinical Findings/Procedure Details: 1) Identification of gastric arteries, cystic arteries, falciform arteries arising from hepatic arteries. 2) Gastroduodenal artery origin in relation to other hepatic arteries and its importance. 3) Phrenic artery as extrahepatic collateral blood suply to liver tumors. 4) Patterns of perfusion of hepatic lesions and principle of redistribution. Conclusion and/or Teaching Points: The mesenteric arterial arcade and hepatic arterial bed demonstrate a wide spectrum of variation. An understanding of arterial variants plays a key role in pre-procedural planning, catheterization and delivery of therapeutic agent. Altered regional hepatic perfusion mapping is required to optimize intervention; more so in the presence of hepatic malignancy. New liver directed therapies, such as radioembolization, mandate meticulous comprehension of normal and variant mesenteric arterial anatomy.
Abstract No. 279 Incidence and detection of dual blood supply to hepatocellular carcinoma located in watershed regions of segment IV and VIII during transarterial chemoembolization
Poster Sessions
M. Abdelmaksoud, G.L. Hwang, J.D. Louie, D.Y. Sze, N. Kothary; Interventional Radiology, Stanford University, Stanford, CA Purpose: Hepatocellular carcinoma (HCC) located in watershed regions of segments IV and VIII are known to have arterial supply from both the left and the right hepatic arteries. In this study we report the incidence and detection of dual hepatic supply in HCC during transarterial chemoembolization. Implication on management of these tumors is also reported. Materials and Methods: We retrospectively reviewed all angiographic images of patients undergoing transarterial chemoembolization for HCC from August 2008 to August 2009. Patients with tumors ⬍ 4 cm were selected for this data analysis. Digital subtraction angiography (DSA) and C-arm CT (CACT) images
were reviewed and we noted whether dual blood supply was recognized prospectively or on follow-up studies. Results: Of the 253 patients who underwent 352 chemoembolizations, 49 patients with 57 tumors located in watershed regions were included in the study (32 segment VIII, 25 segment IV). Of these, 13 tumors (22.8%) in 13 patients (26.5%) had dual blood supply. 9 (69.2%) were in segment IV and 4 (30.8%), in segment VIII (p⫽.036). Dual supply was identified prospectively in 7 (53.8%) tumors, while in 6 (46.2%) the presence of viable disease on follow-up resulted in additional treatment that identified dual supply. Conclusion: Tumors in watershed regions of the liver, especially in segment IV, have a high propensity for dual blood supply. Interrogation of both right and left hepatic arteries is essential to ensure complete treatment.
Abstract No. 280 Detection of small hepatocellular carcinoma during transarterial chemoembolization: Comparison between C-arm CT and digital subtraction angiography M. Abdelmaksoud, G.L. Hwang, J.D. Louie, L. Hofmann, D.Y. Sze, N. Kothary; Interventional Radiology, Stanford University, Stanford, CA Purpose: Small hepatocellular carcinomas (HCC) ⬍ 2 cm in diameter are often difficult to identify and localize by digital subtraction angiography (DSA) during transarterial chemoembolization. The purpose of our study was to compare C-arm CT (CACT) to DSA in its ability to identify small HCC, distinguish segmental localization and provide an anatomic roadmap for superselective transarterial chemoembolization. Materials and Methods: Two interventional radiologists retrospectively reviewed 262 transarterial chemoembolizations performed on 180 consecutive patients treated from January 2008 to August 2009. Patients with a maximum of 3 hypervascular tumors ⱕ 2 cm detected by preprocedural imaging (CT or MRI) were selected for the analysis. We examined 100 tumors in 65 patients who underwent 74 procedures. Proper or common hepatic arteriograms (DSA) in the antero-posterior and oblique projections, selective segmental hepatic arteriograms (DSA), and contrast medium enhanced CACT were reviewed for each patient. Diagnostic ability to identify and locate the tumors was compared between modalities. The number of acquisitions, radiation dose, and contrast medium used were also compared. Results: The sensitivities of non-selective DSA, selective DSA and CACT in identifying the tumors were 64%, 84% and 98%, respectively (P ⫽ 0.057). The mean number of DSA and CACT acquisitions in the study group was 6.6 and 1.5, respectively. Total volume of iodinated contrast used was 60.4 ml (30 –125ml), of which contrast enhanced CACT accounted for 20.7% (12.5 ml, range 3–30ml). Conclusion: CACT is more sensitive than DSA for identifying and localizing hypervascular HCC ⬍ 2 cm. An enhanced CACT may provide crucial or additional information not available by the corresponding DSA acquisitions in two projections. We propose CACT should be performed following catheterization of the common or proper hepatic artery in lieu of multiple DSA acquisitions. Although each CACT acquisition has the radiation exposure equivalent to two DSA acquisitions, the information provided by CACT would reduce the number of subsequent DSA acquisitions and subsequently the total radiation dose and volume of iodinated contrast used may all be decreased.