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Liu X, Ellens N, Williams E, Burdette EC, Karmarkar P, Weiss CR, Kraitchman D, Bottomley PA. High-resolution intravascular MRI-guided perivascular ultrasound ablation. Magn Reson Med 2019; 83:240-253. [PMID: 31402512 DOI: 10.1002/mrm.27932] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 06/24/2019] [Accepted: 07/15/2019] [Indexed: 12/22/2022]
Abstract
PURPOSE To develop and test in animal studies ex vivo and in vivo, an intravascular (IV) MRI-guided high-intensity focused ultrasound (HIFU) ablation method for targeting perivascular pathology with minimal injury to the vessel wall. METHODS IV-MRI antennas were combined with 2- to 4-mm diameter water-cooled IV-ultrasound ablation catheters for IV-MRI on a 3T clinical MRI scanner. A software interface was developed for monitoring thermal dose with real-time MRI thermometry, and an MRI-guided ablation protocol developed by repeat testing on muscle and liver tissue ex vivo. MRI thermal dose was measured as cumulative equivalent minutes at 43°C (CEM43 ). The IV-MRI IV-HIFU protocol was then tested by targeting perivascular ablations from the inferior vena cava of 2 pigs in vivo. Thermal dose and lesions were compared by gross and histological examination. RESULTS Ex vivo experiments yielded a 6-min ablation protocol with the IV-ultrasound catheter coolant at 3-4°C, a 30 mL/min flow rate, and 7 W ablation power. In 8 experiments, 5- to 10-mm thick thermal lesions of area 0.5-2 cm2 were produced that spared 1- to 2-mm margins of tissue abutting the catheters. The radial depths, areas, and preserved margins of ablation lesions measured from gross histology were highly correlated (r ≥ 0.79) with those measured from the CEM43 = 340 necrosis threshold determined by MRI thermometry. The psoas muscle was successfully targeted in the 2 live pigs, with the resulting ablations controlled under IV-MRI guidance. CONCLUSION IV-MRI-guided, IV-HIFU has potential as a precision treatment option that could preserve critical blood vessel wall during ablation of nonresectable perivascular tumors or other pathologies.
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Affiliation(s)
- Xiaoyang Liu
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland.,Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland
| | - Nicholas Ellens
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland.,Acertara Acoustic Laboratories, Longmont, Colorado
| | | | | | - Parag Karmarkar
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland
| | - Clifford R Weiss
- Division of Interventional Radiology, Department of Radiology, Johns Hopkins University, Baltimore, Maryland
| | - Dara Kraitchman
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland
| | - Paul A Bottomley
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland.,Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland
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Can tumor coverage evaluated 24 h post-radiofrequency ablation predict local tumor progression of liver metastases? Int J Comput Assist Radiol Surg 2018; 13:1981-1989. [PMID: 29651715 PMCID: PMC6223751 DOI: 10.1007/s11548-018-1765-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 04/05/2018] [Indexed: 01/12/2023]
Abstract
Purpose To assess the predictive value for local tumor progression (LTP) of geometrical tumor coverage using the contrast-enhanced (ce-)CT images acquired before and within 24 h after radiofrequency (RF) ablation. Methods Twenty patients (6 male and 14 female, median age 62 years) with 45 focal hypovascular liver metastases (16 colorectal carcinoma, 3 melanoma and 1 breast carcinoma) underwent RF ablation under CT-guidance and received a ce-PET/CT scan within 24 h post-procedure. Pre- and post-ablation ce-CT-images were aligned using an interactive procedure and used to verify the tumor coverage of the RF ablation. Results were correlated to LTP as recorded during follow-up performed every 2–3 months after the intervention (mean follow-up of 110 weeks) and compared to standard reading performed by three readers of the ce-CT images. Results Eleven tumors (25%) showed LTP during the follow-up period. One lesion, which did not show LTP, was excluded from analysis due to the poor quality of the alignment. For the remaining, 29 (66%) tumors were completely covered by the ablation zone, 9 (20%) were not, and for 6 (14%) tumors the edges coincided with the edge of the ablation zone. The sensitivity, specificity, PPV and NPV for LTP of having incomplete tumor coverage or no apparent ablative margin versus standard reading of ce-CT were 100, 88, 73 and 100% versus 42, 88, 58 and 82%, respectively. Conclusions Verifying the tumor coverage of liver metastases by an ablation zone through alignment of pre- and early post-ablation ce-CT images has a high predictive value for LTP.
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Early assessment of coagulation necrosis after hepatic microwave ablation: a comparison of non-enhanced and enhanced T1-weighted images. Abdom Radiol (NY) 2017; 42:1781-1787. [PMID: 28180923 DOI: 10.1007/s00261-017-1064-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
PURPOSE To compare the technical success and accuracy of hepatic microwave ablation (MWA) using non-enhanced and enhanced T1-weighted imaging early after ablation. Patients were evaluated with regard to the ablation zone and local tumor progression (LTP). METHODS This retrospective study conducted between September 2014 and December 2015 which consisted of 56 patients with 56 hepatic malignant lesions who underwent percutaneous MWA. Non-enhanced and contrast-enhanced T1-weighted imagings were performed within 2 days after tumor ablation. The efficacy of ablation assessed according to the hyperintense middle zone on non-enhanced T1-weighted images and the non-enhanced area on contrast-enhanced T1-weighted images were compared. The development of LTP during ≥7 months of follow-up served as the end point. RESULTS On the non-enhanced T1-weighted images, the ablated region had a characteristic two-zone structure featuring a hyperintense middle zone and a surrounding hypointense band. Among the 56 patients, LTP developed in ten including seven lesions, in which both the non-enhanced T1-weighted and portal-phase images showed incomplete tumor ablation. In two of the remaining three patients, incomplete tumor ablation was detected on the non-enhanced T1-weighted images, whereas the corresponding portal-phase images showed complete ablation. In the remaining patient, no residual tumor was detected on either the non-enhanced T1-weighted or the portal-phase images. In the 46 patients without LTP, there was no evidence of residual tumor on the non-enhanced T1-weighted or portal-phase images obtained early after ablation. CONCLUSIONS Non-enhanced T1-weighted images are useful in assessing the therapeutic efficacy of MWA of liver tumors early after the procedure.
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Leshem E, Tschabrunn CM, Contreras-Valdes FM, Zilberman I, Anter E. Evaluation of ablation catheter technology: Comparison between thigh preparation model and an in vivo beating heart. Heart Rhythm 2017; 14:1234-1240. [PMID: 28455271 DOI: 10.1016/j.hrthm.2017.04.035] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Indexed: 12/14/2022]
Abstract
BACKGROUND An in vivo animal thigh model is the standard technique for evaluation of ablation catheter technologies, including efficacy and safety of ablation. However, the biophysics of ablation in a thigh model may not be similar to a beating heart. OBJECTIVE The purpose of this study was to compare efficacy and safety of ablation between a thigh preparation model and a beating heart. METHODS In 7 swine, radiofrequency ablation using a 3.5-mm open irrigated catheter (ThermoCool Smart Touch) was performed sequentially in a thigh muscle and in vivo beating ventricles. Ablation was performed at low (30 W for 40 s) and high (40 W for 60 s) energy settings and at similar contact force. Ablation lesions were scanned in high resolution and measured using electronic calipers. RESULTS A total of 152 radiofrequency ablation lesions were measured (86 thigh and 66 heart). At low energy, lesion width was greater in the thigh model (12.19 ± 1.8 mm vs 8.99 ± 2.1 mm; P <.001), whereas lesion depth was similar between the thigh and heart (5.71 ± 0.8 mm vs 5.95 ± 1.3 mm, respectively; P = .18). The planar cross-sectional lesion area was greater in the thigh model (thigh 54.8 ± 10.8 mm2 vs heart 43.1 ± 16.1 mm2; P <.001). At the high-energy setting, lesion depth, width, and area were all greater in the thigh model (thigh 91.5 ± 16.8 mm2 vs heart 56.0 ± 15.5 mm2; P <.001). The incidence of steam pop and char formation was similar between the models. CONCLUSION The thigh preparation model is a reasonable technique for evaluation of ablation catheter technology; however it often results in overestimation of lesion size, especially at higher energy settings.
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Affiliation(s)
- Eran Leshem
- Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - Cory M Tschabrunn
- Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - Fernando M Contreras-Valdes
- Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | | | - Elad Anter
- Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
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Hoffmann R, Rempp H, Schraml C, Schwenzer N, Grözinger G, Blumenstock G, Rothgang E, Pereira PL, Claussen CD, Clasen S. Diffusion-weighted imaging during MR-guided radiofrequency ablation of hepatic malignancies: analysis of immediate pre- and post-ablative diffusion characteristics. Acta Radiol 2015; 56:908-16. [PMID: 25182804 DOI: 10.1177/0284185114545148] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 06/28/2014] [Indexed: 01/26/2023]
Abstract
BACKGROUND Previous studies have shown a benefit of magnetic resonance (MR)-diffusion-weighted imaging (DWI) for follow-up after liver radiofrequency (RF) ablation. However, no data are available concerning acute changes of DWI characteristics immediately after RF ablation. PURPOSE To analyze and compare the MR-diffusion characteristics of pre-interventional hepatic malignancies and the ablation zone during successful MR-guided RF ablation. MATERIAL AND METHODS This retrospective study was conducted in accordance with the guidelines of the local institutional review board. Forty-seven patients with 29 HCC (24 patients) and 30 hepatic metastases (23 patients) underwent MR-guided radiofrequency ablation including DWI before and immediately after ablation (b = 0, 400, 800 s/mm(2)). Two reviewers (A and B) analyzed DWI with focus on detectability of the tumor before ablation and characteristics of the coagulative area after treatment. Mean apparent diffusion coefficient (ADC) was compared between liver, untreated tumor, and hyperintense areas in post-ablative DWI (b = 800 s/mm(2)) with the paired Student's t-test. RESULTS Pre-ablative: the reviewers classified 19/29 (A) and 23/29 (B) HCC and 25/30 (A and B) metastases as detectable in DWI. Post-ablative: a hyperintense rim surrounding the ablation zone was observed in 28/29 treated HCC and 30/30 treated metastases (A and B). A homogenous hypointense central ablation zone was found in 18/29 (A) and 20/29 (B) treated HCC and 17/30 (A & B) treated metastases in DWI. ADC of the rim was significantly lower than ADC of the liver (P < 0.001). CONCLUSION DWI enables visualization of the target tumor in MR-guided liver radiofrequency ablation in most cases. A common post-ablative DWI finding is a hyperintense rim with decreased ADC surrounding the ablation zone.
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Affiliation(s)
- Rüdiger Hoffmann
- Department of Diagnostic and Interventional Radiology, Eberhard Karls University, Tübingen, Germany
| | - Hansjörg Rempp
- Department of Diagnostic and Interventional Radiology, Eberhard Karls University, Tübingen, Germany
| | - Christina Schraml
- Department of Diagnostic and Interventional Radiology, Eberhard Karls University, Tübingen, Germany
| | - Nina Schwenzer
- Department of Diagnostic and Interventional Radiology, Eberhard Karls University, Tübingen, Germany
| | - Gerd Grözinger
- Department of Diagnostic and Interventional Radiology, Eberhard Karls University, Tübingen, Germany
| | - Gunnar Blumenstock
- Department of Clinical Epidemiology and Applied Biometry, Eberhard Karls University, Tübingen, Germany
| | - Eva Rothgang
- Center for Applied Medical Imaging, Siemens Corporate Research, Germany and Baltimore, MD, USA
| | - Philippe L Pereira
- Department of Radiology, Minimally Invasive Therapies and Nuclear Medicine, SLK-Kliniken Heilbronn GmbH, Heilbronn, Germany
| | - Claus D Claussen
- Department of Diagnostic and Interventional Radiology, Eberhard Karls University, Tübingen, Germany
| | - Stephan Clasen
- Department of Diagnostic and Interventional Radiology, Eberhard Karls University, Tübingen, Germany
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Ringe KI, Wacker F, Raatschen HJ. Is there a need for MRI within 24 hours after CT-guided percutaneous thermoablation of the liver? Acta Radiol 2015; 56:10-7. [PMID: 24445091 DOI: 10.1177/0284185114520858] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
BACKGROUND Radiofrequency (RFA) and microwave ablation (MWA) are established minimally invasive techniques for treatment of hepatic tumors. PURPOSE To compare technical success and accuracy of hepatic thermoablation using computed tomography (CT) and magnetic resonance imaging (MRI) acquired 24 h after ablation with regard to evaluation of the post-interventional ablation zone and local tumor recurrence (LTR), and to assess whether additional MRI within 24 h is beneficial. MATERIAL AND METHODS Thirty-two patients (23 men, 9 women; mean age, 60 years) with 48 lesions were included in this retrospective study. CT was performed immediately and MRI was performed 24 h after ablation. Diameter and volume calculations of the ablation zone were compared (T-Test). Technical success and ablation margin distinction, shape, and configuration were evaluated (κ-statistic). Local effectiveness was calculated based on follow-up imaging. Technical success and ablation margin features were correlated with LTR (log-rank test, Fisher's exact test). RESULTS Ablation zone volumes were significantly higher with MRI compared to CT (P < 0.05; mean volume, 55.19 and 45.97 mL). Agreement between CT and MRI for technical success was good (κ = 0.801) and for margin conspicuity fair (κ = 0.289). LTR was 26.1% (mean follow-up, 11.7 months). LTR showed no correlation with technical success or margin conspicuity. CONCLUSION CT and MRI are suited for early evaluation of technical success after thermoablation. Within 24 h a significant increase of the ablation volume is observed, which has to be taken into account when interpreting immediate postprocedural imaging and treating lesions near critical structures. Additional MRI 24 h after ablation seems of limited value regarding prognosis of LTR, especially with regards to evaluation of ablation margin shape and conspicuity.
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Affiliation(s)
- Kristina Imeen Ringe
- Hannover Medical School, Department of Diagnostic and Interventional Radiology, Hannover, Germany
| | - Frank Wacker
- Hannover Medical School, Department of Diagnostic and Interventional Radiology, Hannover, Germany
| | - Hans-Jürgen Raatschen
- Hannover Medical School, Department of Diagnostic and Interventional Radiology, Hannover, Germany
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Postinterventional MRI findings following MRI-guided laser ablation of osteoid osteoma. Eur J Radiol 2014; 83:696-702. [DOI: 10.1016/j.ejrad.2013.12.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Revised: 12/09/2013] [Accepted: 12/12/2013] [Indexed: 11/22/2022]
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8
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Perälä J, Klemola R, Kallio R, Li C, Vihriälä I, Salmela PI, Tervonen O, Sequeiros RB. MRI-guided laser ablation of neuroendocrine tumor hepatic metastases. Acta Radiol Short Rep 2014; 3:2047981613499753. [PMID: 24778794 PMCID: PMC4001425 DOI: 10.1177/2047981613499753] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 07/10/2013] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Neuroendocrine tumors (NET) represent a therapeutically challenging and heterogeneous group of malignancies occurring throughout the body, but mainly in the gastrointestinal system. PURPOSE To describe magnetic resonance imaging (MRI)-guided laser ablation of NET liver metastases and assess its role within the current treatment options and methods. MATERIAL AND METHODS Two patients with NET tumor hepatic metastases were treated with MRI-guided interstitial laser ablation (LITT). Three tumors were treated. Clinical follow-up time was 10 years. RESULTS Both patients were successfully treated. There were no local recurrences at the ablation site during the follow-up. Both patients had survived at 10-year follow-up. One patient is disease-free. CONCLUSION MRI-guided laser ablation can be used to treat NET tumor liver metastases but combination therapy and a rigorous follow-up schedule are recommended.
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Affiliation(s)
- Jukka Perälä
- Department of Radiology, Oulu University Hospital, Oulu, Finland
| | - Rauli Klemola
- Department of Radiology, Southern Ostrobothnia Hospital, Seinäjoki, Finland
| | - Raija Kallio
- Department of Oncology, Oulu University Hospital, Finland
| | - Chengli Li
- Shandong Provincial Medical Imaging Research Institute, Shandong University, Jinan, Shandong, PR China
| | - Ilkka Vihriälä
- Department of Medicine, Central Ostrobothnia Hospital, Kokkola, Finland
| | - Pasi I Salmela
- Department of Medicine, Division of Endocrinology, Oulu University Hospital, Oulu, Finland
| | - Osmo Tervonen
- Department of Radiology, Oulu University Hospital, Oulu, Finland
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Burns SK, Dodd GD, McManus LM, Cardan RA, Peng Q, Orsi MD, Head HW, Blakemore DL, Blume JD, Fullerton GD, Green TJ. 3T Magnetic Resonance Imaging Accurately Depicts Radiofrequency Ablation Zones in a Blood-perfused Bovine Liver Model. J Vasc Interv Radiol 2012; 23:801-8. [DOI: 10.1016/j.jvir.2012.01.076] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2011] [Revised: 01/25/2012] [Accepted: 01/26/2012] [Indexed: 10/28/2022] Open
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Yung JP, Shetty A, Elliott A, Weinberg JS, McNichols RJ, Gowda A, Hazle JD, Stafford RJ. Quantitative comparison of thermal dose models in normal canine brain. Med Phys 2010; 37:5313-21. [PMID: 21089766 DOI: 10.1118/1.3490085] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
PURPOSE Minimally invasive thermal ablative therapies as alternatives to conventional surgical management of solid tumors and other pathologies is increasing owing to the potential benefits of performing these procedures in an outpatient setting with reduced complications and comorbidity. Magnetic resonance temperature imaging (MRTI) measurement allows existing thermal dose models to use the spatiotemporal temperature history to estimate the thermal damage to tissue. However, the various thermal dose models presented in the literature employ different parameters and thresholds, affecting the reliability of thermal dosimetry. In this study, the authors quantitatively compared three thermal dose models (Arrhenius rate process, CEM43, and threshold temperature) using the dice similarity coefficient (DSC). METHODS The DSC was used to compare the spatial overlap between the region of thermal damage as predicted by the models for in vivo normal canine brain during thermal therapy to the region of thermal damage as revealed by contrast-enhanced T1-weighted images acquired immediately after therapy (< 20 min). The outer edge of the hyperintense rim of the ablation region was used as the surrogate marker for the limits of thermal coagulation. The DSC was also used to investigate the impact of varying the thresholds on each models' ability to predict the zone of thermal necrosis. RESULTS At previously reported thresholds, the authors found that all three models showed good agreement (defined as DSC > 0.7) with post-treatment imaging. All three models examined across the range of commonly applied thresholds consistently showed highly accurate spatial overlap, low variability, and little dependence on temperature uncertainty. DSC values corresponding to cited thresholds were not significantly different from peak DSC values. CONCLUSIONS Thus, the authors conclude that the all three thermal dose models can be used as a reliable surrogate for postcontrast tissue damage verification imaging in rapid ablation procedures and can also be used to enhance the capability of MRTI to control thermal therapy in real time.
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Affiliation(s)
- Joshua P Yung
- Department of Imaging Physics, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030, USA
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Bangard C, Stippel DL, Berg F, Kasper HU, Hellmich M, Fischer JH, Hölscher A, Lackner K, Gossmann A. Conspicuity of zones of ablation after radiofrequency ablation in porcine livers: Comparison of an extracellular and an SPIO contrast agent. J Magn Reson Imaging 2008; 28:263-70. [DOI: 10.1002/jmri.21423] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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Clasen S, Pereira PL. Magnetic resonance guidance for radiofrequency ablation of liver tumors. J Magn Reson Imaging 2008; 27:421-33. [PMID: 18219677 DOI: 10.1002/jmri.21264] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Image-guided thermal ablation of liver tumors is a minimally invasive treatment option. Techniques used for thermal ablation are radiofrequency (RF) ablation, laser interstitial thermotherapy (LITT), microwave (MW) ablation, high-intensity focused ultrasound (HIFU), and cryoablation. Among these techniques RF ablation attained widespread consideration. Image guidance should ensure a precise ablation therapy leading to a complete coagulation of tumor tissue without injury to critical structures. Therefore, the modality of image guidance has an important impact on the safety and efficacy of percutaneous RF ablation. The current literature regarding percutaneous RF ablation mainly describes the use of computed tomography (CT) and ultrasonography (US) guidance. In addition, interventional MR systems offer the possibility to utilize the advantages of MR imaging such as excellent soft-tissue contrast, multiplanar and interactive capabilities, and sensitivity to thermal effects during the entire RF ablation procedure. Monitoring of thermally induced coagulation by MR imaging is supportive to control the ablation procedure. MR imaging can be advantageously used to guide overlapping ablation if necessary as well as to define the endpoint of RF ablation after complete coverage of the target tissue is verified. Furthermore, monitoring of thermal effects is essential in order to prevent unintended thermal damage from critical structures surrounding the target region. Therefore, MR-guided RF ablation offers the possibility for a safe and effective therapy option in the treatment of primary and secondary hepatic malignancies. The article summarizes the role of MR guidance for RF ablation of liver tumors.
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Affiliation(s)
- Stephan Clasen
- Eberhard-Karls-University, Department of Diagnostic Radiology, Tübingen, Germany
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13
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Pauly KB, Diederich CJ, Rieke V, Bouley D, Chen J, Nau WH, Ross AB, Kinsey AM, Sommer G. Magnetic resonance-guided high-intensity ultrasound ablation of the prostate. Top Magn Reson Imaging 2007; 17:195-207. [PMID: 17414077 DOI: 10.1097/rmr.0b013e31803774dd] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVES This paper describes our work in developing techniques and devices for magnetic resonance (MR)-guided high-intensity ultrasound ablation of the prostate and includes review of relevant literature. METHODS Catheter-based high-intensity ultrasound applicators, in interstitial and transurethral configurations, were developed to be used under MR guidance. Magnetic resonance thermometry and the relevant characteristics and artifacts were evaluated during in vivo thermal ablation of the prostate in 10 animals. Contrast-enhanced MR imaging (MRI) and diffusion-weighted MRI were used to assess tissue damage and compared with histology. RESULTS During evaluation of these applicators, MR thermometry was used to monitor the temperature distributions in the prostate in real time. Magnetic resonance-derived maximum temperature thresholds of 52 degrees C and thermal dose thresholds of 240 minutes were used to control the extent of treatment and qualitatively correlated well with posttreatment imaging studies and histology. The directional transurethral devices are selective in their ability to target well-defined regions of the prostate gland and can be rotated in discrete steps to conform treatment to prescribed boundaries. The curvilinear applicator is the most precise of these directional techniques. Multisectored transurethral applicators, with dynamic angular control of heating and no rotation requirements, offer a fast and less complex means of treatment with less selective contouring. CONCLUSIONS The catheter-based ultrasound devices can produce spatially selective regions of thermal destruction in prostate. The MR thermal imaging and thermal dose maps, obtained in multiple slices through the target volume, are useful for controlling therapy delivery (rotation, power levels, duration). Contrast-enhanced T1-weighted MRI and diffusion-weighted imaging are useful tools for assessing treatment.
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Affiliation(s)
- Kim Butts Pauly
- Department of Radiology, Stanford University, Stanford, CA 94305-5488, USA.
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14
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Boss A, Martirosian P, Schraml C, Clasen S, Fenchel M, Anastasiadis A, Claussen CD, Pereira PL, Schick F. Morphological, contrast-enhanced and spin labeling perfusion imaging for monitoring of relapse after RF ablation of renal cell carcinomas. Eur Radiol 2006; 16:1226-36. [PMID: 16752153 DOI: 10.1007/s00330-005-0098-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2005] [Revised: 09/23/2005] [Accepted: 11/24/2005] [Indexed: 10/25/2022]
Abstract
MR perfusion imaging was applied for the assessment of completeness in the destruction of renal cell carcinomas by RF ablation (RFA) in a pilot study. An arterial spin labeling (ASL) approach was compared to conventional contrast-enhanced T1-weighted (CE-T1w) imaging. Ten patients suffering from renal cell carcinoma were treated by RFA. For the assessment of the extent of coagulation and for the detection of residual tumor, T1-weighted gradient-echo imaging, T2-weighted spin echo imaging and two different perfusion imaging techniques were performed before, 1 day and 6 weeks after RFA at 1.5 T. Perfusion imaging comprised CE-T1 weighted and FAIR-TrueFISP ASL imaging. Perfusion images recorded in the acute stage after RFA showed higher compliance to the definitive ablation volume reached after 6 weeks than T2-weighted images, which underestimated the true necrosis size. In the detection of residual tumor tissue, both modalities complimented each other. The exclusion of residual tumor tissue could more reliably be performed using perfusion-imaging methods. Both perfusion-imaging modalities showed sufficient imaging quality for post-interventional monitoring. Perfusion imaging provides a higher predictability of the completeness of tumor ablation and extent of coagulation than T2-weighted imaging alone. Since the results of the FAIR-TrueFISP sequence are promising, the administration of potentially nephrotoxic contrast media may be avoided in the respective patient cohort.
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Affiliation(s)
- Andreas Boss
- Section of Experimental Radiology, Eberhard Karls University of Tübingen, Hoppe Seyler Strasse 3, 72076 Tübingen, Germany.
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Gaffke G, Gebauer B, Knollmann FD, Helmberger T, Ricke J, Oettle H, Felix R, Stroszczynski C. Use of Semiflexible Applicators for Radiofrequency Ablation of Liver Tumors. Cardiovasc Intervent Radiol 2005; 29:270-5. [PMID: 16328685 DOI: 10.1007/s00270-005-0052-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
PURPOSE To evaluate the feasibility and potential advantages of the radiofrequency ablation of liver tumors using new MRI-compatible semiflexible applicators in a closed-bore high-field MRI scanner. METHODS We treated 8 patients with 12 malignant liver tumors of different origin (5 colorectal carcinoma, 2 cholangiocellular carcinoma, 1 breast cancer) under MRI guidance. Radiofrequency ablation (RFA) was performed using 5 cm Rita Starburst Semi-Flex applicators (Rita Medical Systems, Milwaukee, WI, USA) which are suitable for MR- and CT-guided interventions and a 150 W RF generator. All interventions were performed in a closed-bore 1.5 T high-field MRI scanner for MRI-guided RFA using fast T1-weighted gradient echo sequences and T2-weighted ultra-turbo spin echo sequences. Control and follow-up MRI examinations were performed on the next day, at 6 weeks, and every 3 months after RFA. Control MRI were performed as double-contrast MRI examinations (enhancement with iron oxide and gadopentetate dimeglumine). All interventions were performed with the patient under local anesthesia and analgo-sedation. RESULTS The mean diameter of the treated hepatic tumors was 2.4 cm (+/-0.6 cm, range 1.0-3.2 cm). The mean diameter of induced necrosis was 3.1 cm (+/-0.4 cm). We achieved complete ablation in all patients. Follow-up examinations over a duration of 7 months (+/-1.3 months, range 4-9 month) showed a local control rate of 100% in this group of patients. All interventions were performed without major complications; only 2 subcapsular hematomas were documented. CONCLUSION RFA of liver tumors using semiflexible applicators in closed-bore 1.5 T scanner systems is feasible. These applicators might simplify the RFA of liver tumors under MRI control. The stiff distal part of the applicator facilitates its repositioning.
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Affiliation(s)
- G Gaffke
- Klinik für Strahlenheilkunde und Poliklinik, Charite, Universitätsmedizin Berlin, Campus Virchow-Klinikum, Augustenburger Platz 1, 13353, Berlin, Germany.
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Breen MS, Lazebnik RS, Wilson DL. Three-Dimensional Registration of Magnetic Resonance Image Data to Histological Sections with Model-Based Evaluation. Ann Biomed Eng 2005; 33:1100-12. [PMID: 16133918 DOI: 10.1007/s10439-005-5778-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2003] [Accepted: 04/08/2005] [Indexed: 10/25/2022]
Abstract
We developed a three-dimensional (3D) registration method to align medical scanner data with histological sections. After acquiring 3D medical scanner images, we sliced and photographed the tissue using, a custom apparatus, to obtain a volume of tissue section images. Histological samples from the sections were digitized using a video microscopy system. We aligned the histology and medical images to the reference tissue images using our 3D registration method. We applied the method to correlate in vivo magnetic resonance (MR) and histological measurements for radio-frequency thermal ablation lesions in rabbit thighs. For registration evaluation, we used an ellipsoid model to describe the lesion surfaces. The model surface closely fit the inner (M1) and outer (M2) boundaries of the hyperintense region in MR lesion images, and the boundary of necrosis (H1) in registered histology images. We used the distance between the model surfaces to indicate the 3D registration error. For four experiments, we measured a registration accuracy of 0.96+/- 0.13 mm (mean+/-SD) from the absolute distance between the M2 and H1 model surfaces, which compares favorably to the 0.70 mm in-plane MR voxel dimension. This suggests that our registration method provides sufficient spatial correspondence to correlate 3D medical scanner and histology data.
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Affiliation(s)
- Michael S Breen
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
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Current awareness in NMR in biomedicine. NMR IN BIOMEDICINE 2003; 16:510-517. [PMID: 14719526 DOI: 10.1002/nbm.806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
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Lazebnik RS, Breen MS, Fitzmaurice M, Nour SG, Lewin JS, Wilson DL. Radio-frequency-induced thermal lesions: Subacute magnetic resonance appearance and histological correlation. J Magn Reson Imaging 2003; 18:487-95. [PMID: 14508786 DOI: 10.1002/jmri.10382] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To investigate the relationship between subacute magnetic resonance (MR) images of radio-frequency (RF) ablation lesions and tissue viability as determined from histological tissue samples. MATERIALS AND METHODS We generated lesions (N = 5) in a rabbit thigh model. Four days later, we obtained in vivo T(2)- and contrast-enhanced (CE) T(1)-weighted images and ex vivo histological samples approximately perpendicular to the electrode path. Using three-dimensional registration and warping, we spatially compared manually segmented boundaries apparent on MR images to boundaries separating distinct histological zones determined from hematoxylin and eosin (H&E) and Masson trichrome (MT) stains, as well as birefringence studies. RESULTS Lesions have a characteristic MR appearance: an outer hyperintense margin (M2) separating background tissue (M3) from an inner core (M1), in both T(2) and CE T(1) images. Histologically, there are two zones of damage: an outer zone of likely nonviable cells (H2) separating background tissue (H3) from an inner core of coagulated nonviable cells (H1). We measured distances between automatically computed correspondence points along histological and MR boundaries. For T(2) and CE T(1) images, respectively, M1 vs. H1 distances were 0.72 +/- 0.99 mm (mean +/- SD) and 0.10 +/- 0.95 mm, while outer M2 vs. H2 boundary distances were 0.26 +/- 1.16 mm and 0.05 +/- 1.08 mm. The discrepancy between histological and MR boundaries was larger than the variability in segmenting MR images, but probably within registration error. There were no significant differences between T(2) and CE T(1) boundaries. CONCLUSION Lesion boundaries apparent in both T(2)- and CE T(1)-weighted MR scans, performed several days postablation, similarly predict the histological response. That is, the lesion core (M1) corresponds to nonviable coagulated cells (H1), while the hyperintense margin (M2) corresponds to likely nonviable cells undergoing necrotic changes (H2).
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Affiliation(s)
- Roee S Lazebnik
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio 44106, USA
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