Blanco Roberto T, Ojala Risto, Kariniemi Juho, Perälä Jukka, Niinimäki Jaakko, Tervonen Osmo
Department of Radiology, Oulu University Hospital, P.O. Box 90029, Finland.
Eur J Radiol. 2005 Nov;56(2):130-42. doi: 10.1016/j.ejrad.2005.03.033.
Magnetic resonance imaging (MRI) is a cutting edge imaging modality in detecting diseases and pathologic tissue. The superior soft tissue contrast in MRI allows better definition of the pathology. MRI is increasingly used for guiding, monitoring and controlling percutaneous procedures and surgery. The rapid development of interventional techniques in radiology has led to integration of imaging with computers, new therapy devices and operating room like conditions. This has projected as faster and more accurate imaging and hence more demanding procedures have been applied to the repertoire of the interventional radiologist. In combining features of various other imaging modalities and adding some more into them, interventional MRI (IMRI) has potential to take further the interventional radiology techniques, minimally invasive therapies and surgery. The term "Interventional MRI" consists in short all those procedures, which are performed under MRI guidance. These procedures can be either percutaneous or open surgical of nature. One of the limiting factors in implementing MRI as guidance modality for interventional procedures has been the fact, that most widely used magnet design, a cylindrical magnet, is not ideal for guiding procedures as it does not allow direct access to the patient. Open, low field scanners usually operating around 0.2 T, offer this feature. Clumsy hardware, bad patient access, slow image update frequency and strong magnetic fields have been other limiting factors for interventional MRI. However, the advantages of MRI as an imaging modality have been so obvious that considerable development has taken place in the 20-year history of MRI. The image quality has become better, ever faster software, new innovative sequences, better MRI hardware and increased computing power have accelerated imaging speed and image quality to a totally new level. Perhaps the most important feature in the recent development has been the introduction of open configuration low field MRI devices in the early 1990s; this enabled direct patient access and utilization of the MRI as an interventional device. This article reviews the current status of interventional and intraoperative MRI with special emphasis in low field surrounding.
磁共振成像（MRI）是检测疾病和病理组织的前沿成像方式。MRI卓越的软组织对比度有助于更清晰地界定病变。MRI越来越多地用于引导、监测和控制经皮操作及手术。放射学介入技术的快速发展促使成像技术与计算机、新型治疗设备以及类似手术室的环境相结合。这带来了更快、更精确的成像，因此更具挑战性的操作也被纳入介入放射科医生的业务范围。通过结合各种其他成像方式的特点并增添更多功能，介入性MRI（IMRI）有潜力进一步推动介入放射学技术、微创治疗和手术的发展。“介入性MRI”一词简而言之涵盖了所有在MRI引导下进行的操作。这些操作可以是经皮的，也可以是开放性手术性质的。将MRI用作介入操作的引导方式的一个限制因素是，最广泛使用的磁体设计——圆柱形磁体，并不适合引导操作，因为它不便于直接接触患者。开放式低场扫描仪通常在0.2T左右运行，具备这一特性。笨拙的硬件、患者进出不便、图像更新频率慢以及强磁场一直是介入性MRI的其他限制因素。然而，MRI作为一种成像方式的优势非常明显，以至于在其20年的发展历程中取得了长足的进步。图像质量变得更好，软件更新更快，出现了新的创新序列，MRI硬件得到改进，计算能力增强，成像速度和图像质量提升到了一个全新的水平。也许近期发展中最重要的特点是在20世纪90年代初引入了开放式低场MRI设备；这使得能够直接接触患者，并将MRI用作介入设备。本文回顾了介入性和术中MRI的现状，特别强调了低场环境。
