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Singh S, Siriwardana PN, Johnston EW, Watkins J, Bandula S, Illing R, Davidson BR. Perivascular extension of microwave ablation zone: demonstrated using an ex vivo porcine perfusion liver model<sup/>. Int J Hyperthermia 2017; 34:1114-1120. [PMID: 29096566 DOI: 10.1080/02656736.2017.1400119] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Microwave ablation (MWA) has been proposed to suffer less from the heat sink effect compared to radiofrequency ablation but has been reported to cause extension of the ablation zone along intrahepatic vessels in clinical practice. To study this effect in detail, eight fresh porcine livers were perfused in an ex vivo organ perfusion system. Livers were perfused with oxygenated, O-positive human blood at 37 °C. Perfusion was discontinued immediately before ablation in the non-perfused group (n = 4) whilst in the perfused group (n = 4) perfusion was maintained during MWA (140 W X 2 min). Large intrahepatic vessels (> 6 mm) were avoided using ultrasound. MWA zones were bisected within 30 min of perfusion termination and sections were fixed in formalin and stained with H&E and NADH to assess cell viability. Magnetic resonance imaging (MRI) was performed on two livers (one perfused, one non-perfused) to provide imaging correlation before sectioning. Twenty-one out of a total of 30 MW ablation zones (70%) showed extension of the ablation zone along a vessel. There was no statistically significant difference (p = 1) in the incidence of ablation zone extension between perfused (9/13, 69%) and non-perfused organs (12/17, 71%). MRI also demonstrated ablation zone extension along blood vessels correlating with macroscopy in two livers. NADH staining also confirmed extension of the ablation zone. Liver MWA appears to be commonly associated with propagated thermal injury along adjacent vessels and occurs independent of active blood flow. In order to avoid possible complications through non-target tissue injury, this effect requires further investigation.
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Affiliation(s)
- Saurabh Singh
- a Interventional Oncology Service , University College Hospital , London , UK
| | - Pulathis Nilantha Siriwardana
- b Hepatopancreatobiliary and Liver Transplant Surgery Unit, University Department of Surgery , Royal Free London NHS Foundation Trust and University College London , London , UK
| | | | - Jennifer Watkins
- c Department of Cellular Pathology , Royal Free London NHS Foundation Trust , London , UK
| | - Steven Bandula
- a Interventional Oncology Service , University College Hospital , London , UK
| | - Rowland Illing
- a Interventional Oncology Service , University College Hospital , London , UK
| | - Brian Ritchie Davidson
- b Hepatopancreatobiliary and Liver Transplant Surgery Unit, University Department of Surgery , Royal Free London NHS Foundation Trust and University College London , London , UK
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Chiang J, Nickel K, Kimple RJ, Brace CL. Potential Mechanisms of Vascular Thrombosis after Microwave Ablation in an in Vivo Liver. J Vasc Interv Radiol 2017; 28:1053-1058. [PMID: 28456355 DOI: 10.1016/j.jvir.2017.03.034] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 02/24/2017] [Accepted: 03/25/2017] [Indexed: 12/21/2022] Open
Abstract
PURPOSE To evaluate potential biologic and thermal mechanisms of the observed differences in thrombosis rates between hepatic vessels during microwave (MW) ablation procedures. MATERIALS AND METHODS MW ablation antennae were placed in single liver lobes of 2 in vivo porcine liver models (n = 3 in each animal; N = 6 total) in the proximity of a large (> 5 mm) portal vein (PV) and hepatic veins (HVs). Each ablation was performed with 100 W for 5 minutes. Conventional ultrasound imaging and intravascular temperature probes were used to evaluate vessel patency and temperature changes during the ablation procedure. Vascular endothelium was harvested 1 hour after ablation and used to characterize genes and proteins associated with thrombosis in PVs and HVs. RESULTS Targeted PVs within the MW ablation zone exhibited thrombosis at a significantly higher rate than HVs (54.5% vs 0.0%; P = .0046). There was a negligible change in intravascular temperature in PVs and HVs during the ablation procedure (0.2°C ± 0.4 vs 0.6°C ± 0.9; P = .46). PVs exhibited significantly higher gene expression than HVs in terms of fold differences in thrombomodulin (2.9 ± 2.0; P = .0001), von Willebrand factor (vWF; 7.6 ± 1.5; P = .0001), endothelial protein C receptor (3.50 ± 0.49; P = .0011), and plasminogen activator inhibitor (1.46 ± 0.05; P = .0014). Western blot analysis showed significantly higher expression of vWF (2.32 ± 0.92; P = .031) in PVs compared with HVs. CONCLUSIONS Large PVs exhibit thrombosis more frequently than HVs during MW ablation procedures. Biologic differences in thrombogenicity, rather than heat transfer, between PVs and HVs may contribute to their different rates of thrombosis.
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Affiliation(s)
- Jason Chiang
- Department of Radiology, University of Wisconsin, 1111 Highland Ave., 1310-O, Madison, WI 53705.
| | - Kwang Nickel
- Department of Radiation Oncology, University of Wisconsin, 1111 Highland Ave., 1310-O, Madison, WI 53705
| | - Randall J Kimple
- Department of Radiation Oncology, University of Wisconsin, 1111 Highland Ave., 1310-O, Madison, WI 53705
| | - Christopher L Brace
- Department of Radiology, University of Wisconsin, 1111 Highland Ave., 1310-O, Madison, WI 53705
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Meloni MF, Chiang J, Laeseke PF, Dietrich CF, Sannino A, Solbiati M, Nocerino E, Brace CL, Lee FT. Microwave ablation in primary and secondary liver tumours: technical and clinical approaches. Int J Hyperthermia 2016; 33:15-24. [PMID: 27416729 DOI: 10.1080/02656736.2016.1209694] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Thermal ablation is increasingly being utilised in the treatment of primary and metastatic liver tumours, both as curative therapy and as a bridge to transplantation. Recent advances in high-powered microwave ablation systems have allowed physicians to realise the theoretical heating advantages of microwave energy compared to other ablation modalities. As a result there is a growing body of literature detailing the effects of microwave energy on tissue heating, as well as its effect on clinical outcomes. This article will discuss the relevant physics, review current clinical outcomes and then describe the current techniques used to optimise patient care when using microwave ablation systems.
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Affiliation(s)
- Maria Franca Meloni
- a Department of Radiology , Interventional Ultrasound, Institute of Care IGEA , Milan , Italy
| | - Jason Chiang
- b Department of Radiology , University of Wisconsin , Madison , Wisconsin , USA
| | - Paul F Laeseke
- b Department of Radiology , University of Wisconsin , Madison , Wisconsin , USA
| | - Christoph F Dietrich
- c Department of Internal Medicine , Caritas Krankenhas Bad Mergentheim , Bad Mergentheim , Germany
| | - Angela Sannino
- d Department of Clinical Medicine and Surgery , University of Naples Federico II , Naples , Italy
| | - Marco Solbiati
- e Department of Electronics, Information and Bioengineering , Politecnico Milano , Milan , Italy
| | - Elisabetta Nocerino
- f Department of Radiology , San Paolo Hospital, University of Milan , Milan , Italy
| | - Christopher L Brace
- b Department of Radiology , University of Wisconsin , Madison , Wisconsin , USA
| | - Fred T Lee
- b Department of Radiology , University of Wisconsin , Madison , Wisconsin , USA
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Chiang J, Cristescu M, Lee MH, Moreland A, Hinshaw JL, Lee FT, Brace CL. Effects of Microwave Ablation on Arterial and Venous Vasculature after Treatment of Hepatocellular Carcinoma. Radiology 2016; 281:617-624. [PMID: 27257951 DOI: 10.1148/radiol.2016152508] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Purpose To characterize vessel occlusion rates and their role in local tumor progression in patients with hepatocellular carcinoma (HCC) who underwent microwave tumor ablation. Materials and Methods This institutional review board approved, HIPAA-compliant retrospective review included 95 patients (75 men and 20 women) with 124 primary HCCs who were treated at a single center between January 2011 and March 2014. Complete occlusion of the portal veins, hepatic veins, and hepatic arteries within and directly abutting the ablation zone was identified with postprocedure contrast material-enhanced computed tomography. For each vessel identified in the ablation zone, its size and antenna spacing were recorded and correlated with vascular occlusion with logistic regression analysis. Local tumor progression rates were then compared between patent and occluded vessels for each vessel type with Fisher exact test. Results Occlusion was identified in 39.7% of portal veins (29 of 73), 15.0% of hepatic veins (six of 40), and 14.2% of hepatic arteries (10 of 70) encompassed within the ablation zone. Hepatic vein occlusion was significantly correlated with a smaller vessel size (P = .036) and vessel-antenna spacing (P = .006). Portal vein occlusion was only significantly correlated with a smaller vessel size (P = .001), particularly in vessels that were less than 3 mm in diameter. Local tumor progression rates were significantly correlated with patent hepatic arteries within the ablation zone (P = .02) but not with patent hepatic (P = .57) or portal (P = .14) veins. Conclusion During microwave ablation of HCC, hepatic veins and arteries were resistant to vessel occlusion compared with portal veins, and only arterial patency within an ablation zone was related to local tumor progression. © RSNA, 2016.
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Affiliation(s)
- Jason Chiang
- From the Departments of Radiology (J.C., M.C., M.H.L., A.M., J.L.H., F.T.L., C.L.B.) and Biomedical Engineering (J.C., F.T.L., C.L.B.), University of Wisconsin-Madison, 1111 Highland Ave, WIMR 1310-O, Madison, WI 53705
| | - Mircea Cristescu
- From the Departments of Radiology (J.C., M.C., M.H.L., A.M., J.L.H., F.T.L., C.L.B.) and Biomedical Engineering (J.C., F.T.L., C.L.B.), University of Wisconsin-Madison, 1111 Highland Ave, WIMR 1310-O, Madison, WI 53705
| | - Matthew H Lee
- From the Departments of Radiology (J.C., M.C., M.H.L., A.M., J.L.H., F.T.L., C.L.B.) and Biomedical Engineering (J.C., F.T.L., C.L.B.), University of Wisconsin-Madison, 1111 Highland Ave, WIMR 1310-O, Madison, WI 53705
| | - Anna Moreland
- From the Departments of Radiology (J.C., M.C., M.H.L., A.M., J.L.H., F.T.L., C.L.B.) and Biomedical Engineering (J.C., F.T.L., C.L.B.), University of Wisconsin-Madison, 1111 Highland Ave, WIMR 1310-O, Madison, WI 53705
| | - J Louis Hinshaw
- From the Departments of Radiology (J.C., M.C., M.H.L., A.M., J.L.H., F.T.L., C.L.B.) and Biomedical Engineering (J.C., F.T.L., C.L.B.), University of Wisconsin-Madison, 1111 Highland Ave, WIMR 1310-O, Madison, WI 53705
| | - Fred T Lee
- From the Departments of Radiology (J.C., M.C., M.H.L., A.M., J.L.H., F.T.L., C.L.B.) and Biomedical Engineering (J.C., F.T.L., C.L.B.), University of Wisconsin-Madison, 1111 Highland Ave, WIMR 1310-O, Madison, WI 53705
| | - Christopher L Brace
- From the Departments of Radiology (J.C., M.C., M.H.L., A.M., J.L.H., F.T.L., C.L.B.) and Biomedical Engineering (J.C., F.T.L., C.L.B.), University of Wisconsin-Madison, 1111 Highland Ave, WIMR 1310-O, Madison, WI 53705
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Chiang J, Willey BJ, Del Rio AM, Hinshaw JL, Lee FT, Brace CL. Predictors of thrombosis in hepatic vasculature during microwave tumor ablation of an in vivo porcine model. J Vasc Interv Radiol 2014; 25:1965-1971.e2. [PMID: 25255704 PMCID: PMC4253571 DOI: 10.1016/j.jvir.2014.07.022] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Revised: 07/18/2014] [Accepted: 07/22/2014] [Indexed: 02/06/2023] Open
Abstract
PURPOSE To evaluate and model the risk of in vivo thrombosis in each hepatic vessel type during hepatic microwave ablation as a function of vessel diameter, velocity, and vessel-antenna spacing. MATERIALS AND METHODS A single microwave ablation antenna was inserted into a single porcine lobe (n = 15 total) adjacent to a hepatic artery, hepatic vein, or portal vein branch. Conventional ultrasound and Doppler ultrasound were used to measure the vessel diameter, blood flow velocity, and vessel-antenna spacing. A microwave ablation zone was created at 100 W for 5 minutes. Thrombus formation was evaluated on ultrasound performed immediately after the procedure. Logistic regression was used to evaluate the predictive value of vessel diameter, blood flow velocity, and vessel-antenna spacing on vascular thrombosis. RESULTS Thrombosis was identified in 53% of portal veins, 13% of hepatic veins, and 0% of hepatic arteries. The average peak blood flow rate of the hepatic artery was significantly greater than the average peak blood flow rate of the hepatic vein and portal vein. Peak blood flow velocity < 12.45 cm/s, vessel diameter < 5.10 mm, and vessel-antenna spacing < 3.75 mm were strong predictors of hepatic vein thrombosis. However, these individual factors were not predictive of the more common portal vein thrombosis. CONCLUSIONS Hepatic arteries do not appear to be at risk for thrombosis during microwave ablation procedures. Portal vein thrombosis was more common than hepatic vein thrombosis during microwave ablation treatments but was not as predictable based on vessel diameter, flow velocity, or vessel-antenna spacing alone.
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Affiliation(s)
- Jason Chiang
- Department of Radiology, University of Wisconsin, 1111 Highland Avenue, WIMR 1310-O, Madison, WI 53705; Department of Biomedical Engineering, University of Wisconsin, 1111 Highland Avenue, WIMR 1310-O, Madison, WI 53705
| | - Bridgett J Willey
- Department of Radiology, University of Wisconsin, 1111 Highland Avenue, WIMR 1310-O, Madison, WI 53705
| | - Alejandro Muñoz Del Rio
- Department of Radiology, University of Wisconsin, 1111 Highland Avenue, WIMR 1310-O, Madison, WI 53705
| | - J Louis Hinshaw
- Department of Radiology, University of Wisconsin, 1111 Highland Avenue, WIMR 1310-O, Madison, WI 53705
| | - Fred T Lee
- Department of Radiology, University of Wisconsin, 1111 Highland Avenue, WIMR 1310-O, Madison, WI 53705
| | - Christopher L Brace
- Department of Radiology, University of Wisconsin, 1111 Highland Avenue, WIMR 1310-O, Madison, WI 53705; Department of Biomedical Engineering, University of Wisconsin, 1111 Highland Avenue, WIMR 1310-O, Madison, WI 53705.
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Abstract
Microwave tissue heating is being increasingly utilised in several medical applications, including focal tumour ablation, cardiac ablation, haemostasis and resection assistance. Computational modelling of microwave ablations is a precise and repeatable technique that can assist with microwave system design, treatment planning and procedural analysis. Advances in coupling temperature and water content to electrical and thermal properties, along with tissue contraction, have led to increasingly accurate computational models. Developments in experimental validation have led to broader acceptability and applicability of these newer models. This review will discuss the basic theory, current trends and future direction of computational modelling of microwave ablations.
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Affiliation(s)
- Jason Chiang
- Department of Radiology, University of Wisconsin – Madison, Madison WI
- Department of Biomedical Engineering, University of Wisconsin – Madison, Madison WI
| | - Peng Wang
- Department of Radiology, University of Wisconsin – Madison, Madison WI
| | - Christopher L. Brace
- Department of Radiology, University of Wisconsin – Madison, Madison WI
- Department of Biomedical Engineering, University of Wisconsin – Madison, Madison WI
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Acute Portal Venous Injury After Microwave Ablation in an In Vivo Porcine Model: A Rare Possible Complication. J Vasc Interv Radiol 2011; 22:947-51. [DOI: 10.1016/j.jvir.2011.03.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2010] [Revised: 02/27/2011] [Accepted: 03/14/2011] [Indexed: 01/20/2023] Open
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