MR Imaging-guided Focused Ultrasound Surgery of Fibroadenomas in the Breast: A Feasibility Study1
Kullervo Hynynen, PhD,
Oliver Pomeroy, MD,
Darrell N. Smith, MD,
Peter E. Huber, MD, PhD,
Nathan J. McDannold, BS,
Joachim Kettenbach, MD,
Janet Baum, MD,
Samuel Singer, MD and
Ferenc A. Jolesz, MD
1 From the Departments of Radiology (K.H., O.P., D.N.S., P.E.H., N.J.M., J.K., F.A.J.) and Surgery (S.S.), Brigham and Women’s Hospital, Harvard Medical School, 75 Francis St, Boston, MA 02115; and the Department of Radiology, Beth Israel Deaconess Medical Center, Boston, Mass (J.B.). Received April 4, 2000; revision requested May 25; revision received June 23; accepted August 1. Supported in part by NCI program grant 67165, research grant CA 46627, contract 282-97-0080 from the U.S. PHS Office on Women’s Health, and a grant from GE Medical Systems. P.E.H. supported by German Research Council (DFG) grant HU 798/1-1. J.K. supported by the Austrian Science Foundation and the Research and Education Fund of the European Congress of Radiology. Address correspondence to K.H. (e-mail: kullervo@bwh.harvard.edu).
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Figure 1. Second-generation mechanical positioning system for MR imaging-guided FUS of breast tumors. The transducer was moved by three MR imaging-compatible ultrasonographic (US) motors that were mounted at the end of the patient table and attached to lead screws and telescoping arms inside the water bath. Three optic encoders tracked the position of the transducer. Rotary encoders (not shown) provided a secondary safety tracking mechanism.
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Figure 2. Fat-suppressed T2-weighted fast SE MR images (2,500/100) obtained for planning on the day of treatment of a fibroadenoma. The patient is lying in a prone position, with the breast positioned on the water pillow. The transducer is outlined at the bottom. Transverse sections (A, C) and the corresponding coronal sections (B, D) of the planning target volume outlined in two sequential planes are shown. The positions of the treatment foci are demonstrated in B and D.
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Figure 3. Temperature-sensitive fast spoiled gradient-echo phase-subtraction MR images (27.3/13.5) of a single 10-second therapeutic sonication in the tumor. Top: MR image shows the temperature elevation at the end of a sonication during therapy in the tumor in Figure 2, A, with proton resonance frequency imaging. The temperature focus appears as a small hyperintense spot in the breast. Bottom: MR images show the temperature time-course of the same sonication in the region of interest. The indicated temperature increase is above body temperature.
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Figure 4. Graph shows mean temperature elevation as a function of time of the hottest voxel of 63 sonications delivered to a breast fibroadenoma, as measured with MR imaging-derived thermometry. The temperature increase was 17.5°-45.2°C. A total of 71 sonications in three planes were delivered to this tumor. Temperature increase could not be reliably monitored in eight sonications because of noise on the images, which was induced by fatty tissue surrounding the tumor.
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Figure 5. MR images show complete response at long-term follow-up of a breast fibroadenoma (circled area) treated with MR imaging-guided FUS in A-D, T2-weighted fat-suppressed fast SE images (A-C: 2,500/100; D: 3,850/100) and E-H, T1-weighted fat-suppressed postcontrast images (E, F: 600/12; G: 400/12; H: 517/12) obtained 2 months before therapy and at 7 days, 6 months, and 3 years after therapy, respectively.
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Figure 6. T1-weighted fat-suppressed fast SE postcontrast MR images (600/12) show incomplete acute response in a fibroadenoma that was treated twice with MR imaging-guided FUS. Left: Image obtained 2 days after the first therapy with inadequate power. Right: Image obtained 2 days after a higher-power therapy demonstrates largely no contrast material uptake in the fibroadenoma, with a rim of enhancing tumor in the top section. Two tumor locations (top-bottom) are presented for both times.
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Copyright © 2001 by the Radiological Society of North America.
