Magnetic resonance imaging clinics of North America
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Magn Reson Imaging Clin N Am · Aug 2005
ReviewMR imaging-controlled focused ultrasound ablation: a noninvasive image-guided surgery.
The history of MR-guided FUS demonstrates the need for merging advanced therapy technology with advanced imaging. Without the ability of MR imaging to localize the tumor margins and without the temperature-sensitive imaging that provides the closed-loop control of energy deposition, this method is inadequate for most clinical applications. Given these limitations,high-intensity focused ultrasound initially appeared to have a narrow application area and was not able to compete with other surgical or ablation methods. ⋯ It is uniquely applicable for image-guided therapy using targeted drug delivery methods and gene therapy. Further advances in this technology will no doubt improve energy deposition and reduce treatment times. In the near future, FUS will offer a viable alternative to conventional surgery and radiation therapy; in the longer-term, it may also enable a host of targeted treatment methods aimed at eradicating or arresting heretofore intractable diseases such as certain brain malignancies and forms of epilepsy.
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Magn Reson Imaging Clin N Am · Aug 2005
ReviewRadiofrequency thermal ablation: the role of MR imaging in guiding and monitoring tumor therapy.
Performing RFA procedures under MR imaging involves two distinct processes: interactive guidance of the RF electrode into the targeted tumor and monitoring the effect of therapy. The justification for using MR imaging for electrode guidance is quite similar to its use to guide biopsy and aspiration procedures, where MR imaging offers advantages related to superior soft tissue contrast, multiplanar capabilities, and high vascular conspicuity that facilitate safe and accurate guidance in selected lesions. ⋯ As such, MR imaging guidance and monitoring enable treatment of the entire tumor on a single-visit basis while avoiding undue overtreatment and preserving often critically needed organ function. Although knowledge of interventional MR imaging concepts and familiarity with its technology and with the related safety issues are indispensable for interventional radiologists attempting thermal ablation procedures in the MR imaging environment, understanding the tissue basis of necrosis imaging is becoming an essential part of the knowledge base for the larger sector of general radiologists who are required to interpret the follow-up MR imaging scans of the increasing number of thermal ablation patients.
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With the rapid evolution of technologic advances in neurosurgery, it is no surprise that the use of MR imaging to guide the performance of safe and effective surgical procedures is at the forefront of development. This article highlights the current capabilities of intraoperative MR-guided surgery for a variety of neurosurgical procedures and traces the evolution of the field to its present level of technical sophistication. The costs of intraoperative MR imaging and its future directions are discussed.