Jolesz Ferenc A, Hynynen Kullervo, McDannold Nathan, Tempany Clare
Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA.
Magn Reson Imaging Clin N Am. 2005 Aug;13(3):545-60. doi: 10.1016/j.mric.2005.04.008.
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. Today, MR imaging-guided FUS has become a safe and effective means of performing probe-delivered thermal ablations and minimally invasive surgery. Moreover, it has the potential to replace treatments that use ionizing radiation such as radiosurgery and brachytherapy. Although the cost of integrating"big ticket" MR imaging systems with complex and expensive phased arrays is high, this expenditure will largely be offset by eliminating hospitalization and anesthesia and by reducing complications. In effect, an investment in this emerging technology will ultimately redound to the benefit of the health care delivery system and, most important, to the patient. The FUS system provides a safe, repeatable treatment approach for benign tumors (eg, uterine fibroid and breast fibroadenoma) that do not require an aggressive approach. MR-guided FUS can also be used for debulking cancerous tissue. It has already been tested as a breast cancer treatment; its application for other malignancies in the brain, liver, and prostate is under development. MR-guided FUS offers an attractive alternative to conventional surgery because it incorporates intraoperative MR imaging, which provides far more precise target definition than is possible with the surgeon's direct visualization of the lesion. MR-guided FUS is undeniably the most promising interventional MR imaging method in the field of image-guided therapy today. It is applicable not only in the thermal coagulative treatment of tumors but also in several other medical situations for which invasive surgery or radiation may not be treatment options. The use of FUS for treating vascular malformation or functional disorders of the brain is also exciting. 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.
磁共振引导聚焦超声（MR-guided FUS）的发展历程表明，将先进治疗技术与先进成像技术相结合是很有必要的。如果没有磁共振成像来定位肿瘤边缘，也没有能提供能量沉积闭环控制的温度敏感成像技术，这种方法对于大多数临床应用来说是不够的。鉴于这些局限性，高强度聚焦超声最初似乎应用领域狭窄，无法与其他手术或消融方法竞争。如今，磁共振成像引导的聚焦超声已成为一种安全有效的方法，可用于进行经探头的热消融和微创手术。此外，它有潜力取代使用电离辐射的治疗方法，如放射外科手术和近距离放射治疗。尽管将“昂贵的”磁共振成像系统与复杂且昂贵的相控阵集成的成本很高，但通过消除住院和麻醉以及减少并发症，这一支出将在很大程度上得到抵消。实际上，对这项新兴技术的投资最终将有利于医疗保健系统，最重要的是有利于患者。聚焦超声系统为不需要激进治疗方法的良性肿瘤（如子宫肌瘤和乳腺纤维瘤）提供了一种安全、可重复的治疗方法。磁共振引导的聚焦超声还可用于减少癌组织体积。它已被作为乳腺癌治疗方法进行了测试；其在脑、肝和前列腺等其他恶性肿瘤中的应用正在研发中。磁共振引导的聚焦超声为传统手术提供了一种有吸引力的替代方案，因为它结合了术中磁共振成像，与外科医生直接观察病变相比，能提供更精确的靶点定义。不可否认，磁共振引导的聚焦超声是当今图像引导治疗领域最有前景的介入性磁共振成像方法。它不仅适用于肿瘤的热凝固治疗，还适用于其他一些可能不适合采用侵入性手术或放射治疗的医疗情况。将聚焦超声用于治疗脑部血管畸形或功能障碍也令人兴奋。它特别适用于使用靶向药物递送方法和基因治疗的图像引导治疗。这项技术的进一步发展无疑将改善能量沉积并缩短治疗时间。在不久的将来，聚焦超声将为传统手术和放射治疗提供可行的替代方案；从长远来看，它还可能催生一系列旨在根除或控制某些脑部恶性肿瘤和癫痫等迄今难以治疗的疾病的靶向治疗方法。
