HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) All Versions of this Article: 2242011269v1 224/2/452    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Nour, S. G. Articles by Lewin, J. S. Search for Related Content PubMed PubMed Citation Articles by Nour, S. G. Articles by Lewin, J. S.

MR Imaging–guided Radio-frequency Thermal Ablation of the Lumbar Vertebrae in Porcine Models¹

¹ From the Depts of Radiology (S.G.N., A.J.A., I.C.S.M., J.L.D., J.S.L.), Pathology (S.N.E.), and Biomedical Engineering (J.L.D.), Univ Hospitals of Cleveland/Case Western Reserve Univ School of Medicine, 11100 Euclid Ave, Cleveland, OH 44106-5056. Received Jul 24, 2001; revision requested Sep 12; revision received Dec 21; accepted Feb 25, 2002. Univ Hospitals of Cleveland/Case Western Reserve Univ Interventional MR Program supported in part through research collaborations with Siemens Medical Systems and Radionics. Also supported by grants from Whitaker Foundation, American Cancer Society, and NIH 1R01 CA81431-01A1 and 1R01-CA84433-01. Address correspondence to J.S.L. (e-mail: lewin@uhrad.com).

PURPOSE: To test the hypotheses that (a) magnetic resonance (MR) imaging–guided radio-frequency (RF) thermal ablation of the vertebrae is feasible in porcine models, (b) procedure safety depends on the location of ablation within the vertebra, and (c) MR imaging allows accurate monitoring of induced thermal lesion size and shape.

MATERIALS AND METHODS: Ten percutaneous MR imaging–guided RF thermal ablations were randomized over various lumbar vertebral levels and locations in seven pigs. Animals were followed up for 2, 7, or 14 days before sacrifice. Thermal lesion size and shape as measured on MR images obtained immediately after ablation and at follow-up were compared with gross pathologic findings. Mean absolute differences between lesion diameters at pathologic examination and MR imaging were evaluated by using a paired t test, as were differences between lesion-to-vertebra contrast-to-noise ratios obtained for each sequence. Clinical and imaging data were correlated with histologic findings.

RESULTS: Successful RF electrode placement in the targeted part of the vertebra was achieved in all procedures. Ablations performed away from neural elements were safe to perform. Pedicular ablations resulted in radiculopathy, whereas ablations performed directly over the posterior cortex resulted in paraplegia. Lesion sizes measured on T2-weighted images were closest to those measured at gross pathologic examination (mean absolute difference, 0.72 mm ± 0.83 [SD]), followed by those measured on contrast material–enhanced T1-weighted (1.27 mm ± 0.83) and short inversion time inversion-recovery (STIR) (1.5 mm ± 1.84) images. Size measurements obtained on T2-weighted images were significantly closer to gross pathologic measurements than were those obtained on contrast-enhanced T1-weighted images (P = .013) but were not different from those obtained on STIR (P = .27) images. The contrast-to-noise ratio was significantly higher for contrast-enhanced T1-weighted images than for T2-weighted (P < .001) or STIR (P < .001) images.

CONCLUSION: MR imaging–guided RF thermal ablation of the vertebrae is feasible in porcine models, but the safety of the procedure depends on the location of ablation within the vertebra. MR imaging allows accurate monitoring of thermal lesion size and shape.

© RSNA, 2002

Index terms: Interventional procedures, experimental studies, 33.1269 • Magnetic resonance (MR), guidance, 33.121412 • Radiofrequency (RF) ablation, 33.1269 • Spine, interventional procedures, 33.1269

This article has been cited by other articles:

				A. Adachi, T. Kaminou, T. Ogawa, T. Kawai, Y. Takaki, K. Sugiura, Y. Ohuchi, and M. Hashimoto Heat Distribution in the Spinal Canal during Radiofrequency Ablation for Vertebral Lesions: Study in Swine Radiology, May 1, 2008; 247(2): 374 - 380. [Abstract] [Full Text] [PDF]

				C. P. Cantwell, J. Kerr, J. O'Byrne, and S. Eustace MRI Features After Radiofrequency Ablation of Osteoid Osteoma with Cooled Probes and Impedance-Control Energy Delivery. Am. J. Roentgenol., May 1, 2006; 186(5): 1220 - 1227. [Abstract] [Full Text] [PDF]

				C. P. Cantwell, J. O'Byrne, and S. Eustace Radiofrequency ablation of osteoid osteoma with cooled probes and impedance-control energy delivery. Am. J. Roentgenol., May 1, 2006; 186(5 Suppl): S244 - S248. [Abstract] [Full Text] [PDF]

				S. G. Nour, J. S. Lewin, M. Gutman, C. Hillenbrand, F. K. Wacker, J. W. Wong, I. C. Mitchell, C. B. Armstrong, M. M. Hashim, J. L. Duerk, et al. Percutaneous MR Imaging- guided Radiofrequency Interstitial Thermal Ablation of Tongue Base in Porcine Models: Implications for Obstructive Sleep Apnea Syndrome Radiology, February 1, 2004; 230(2): 359 - 368. [Abstract] [Full Text] [PDF]

				O. Schaefer, C. Lohrmann, M. Markmiller, P. Uhrmeister, and M. Langer Combined Treatment of a Spinal Metastasis with Radiofrequency Heat Ablation and Vertebroplasty Am. J. Roentgenol., April 1, 2003; 180(4): 1075 - 1077. [Full Text] [PDF]