Volume 8, Issue 4 pp. 933-943
Original Research
Full Access

Monitoring and visualization techniques for MR-guided laser ablations in an open MR system

Joachim Kettenbach MD

Corresponding Author

Joachim Kettenbach MD

Department of Radiology, Harvard Medical School and Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115

Department of Radiology, Harvard Medical School and Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115Search for more papers by this author
Stuart G. Silverman MD

Stuart G. Silverman MD

Department of Radiology, Harvard Medical School and Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115

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Nobuhiko Hata PhD

Nobuhiko Hata PhD

Department of Radiology, Harvard Medical School and Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115

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Kagayaki Kuroda PhD

Kagayaki Kuroda PhD

Department of Electrical Engineering, Faculty of Engineering, Osaka City University, Japan

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Pairash Saiviroonporn PhD

Pairash Saiviroonporn PhD

Department of Radiology, Harvard Medical School and Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115

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Gary P. Zientara PhD

Gary P. Zientara PhD

Department of Radiology, Harvard Medical School and Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115

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Paul R. Morrison MS

Paul R. Morrison MS

Department of Radiology, Harvard Medical School and Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115

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Stephen G. Hushek PhD

Stephen G. Hushek PhD

General Electric, Medical Systems, Milwaukee, WI

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Peter McL. Black MD, PhD

Peter McL. Black MD, PhD

Division of Neurosurgery, Department of Surgery, Harvard Medical School and Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115

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Ron Kikinis MD

Ron Kikinis MD

Department of Radiology, Harvard Medical School and Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115

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Ferenc A. Jolesz MD

Ferenc A. Jolesz MD

Department of Radiology, Harvard Medical School and Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115

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First published: 17 November 2005
Citations: 76

Abstract

Our purpose was to develop temperature-sensitive MR sequences and image-processing techniques to assess their potential of monitoring interstitial laser therapy (ILT) in brain tumors (n = 3) and liver tumors (n = 7). ILT lasted 2 to 26 minutes, whereas images from T1-weighted fast-spin-echo (FSE) or spoiled gradient-recalled (SPGR) sequences were acquired within 5 to 13 seconds. Pixel subtraction and visualization of T1-weighted images or optical flow computation was done within less than 110 msec. Alternating phase-mapping of real and imaginary components of SPGR sequences was performed within 220 msec. Pixel subtraction of T1-weighted images identified thermal changes in liver and brain tumors but could not evaluate the temperature values as chemical shift-based imaging, which was, however, more affected by susceptibility effects and motion. Optical flow computation displayed the predicted course of thermal changes and revealed that the rate of heat deposition can be anisotropic, which may be related to heterogeneous tumor structure and/or vascularization.

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