Rausch Dana R, Hendrick R Edward
Department of Radiology, Mount Sinai Medical Center, Box 1234, 1 Gustave L. Levy Place, New York, NY 10029, USA.
Radiographics. 2006 Sep-Oct;26(5):1469-84. doi: 10.1148/rg.265055176.
Magnetic resonance (MR) imaging, when used in conjunction with mammography and ultrasonography, can be a powerful tool for breast imaging. There are various clinical scenarios in which MR imaging may provide key information that leads to an alteration in treatment plans (eg, by demonstrating features that were occult at physical examination or conventional imaging). Although many benign and malignant entities enhance at contrast material-enhanced breast MR imaging, the morphologic characteristics and kinetic profiles of lesions help narrow the differential diagnosis. To optimize the quality of the morphologic and kinetic information yielded by breast MR imaging, the radiologist must attend to various practical and technical prerequisites: A bilateral breast coil should be used with prone positioning of the patient. An MR imaging system with a high-field-strength magnet is needed, and the magnetic field must be homogeneous across the field of view, which should include both breasts. A T2-weighted sequence should be applied first to identify any cysts and should be followed by three-dimensional imaging with a T1-weighted spoiled gradient-echo sequence after the intravenous administration of a gadolinium chelate. To minimize artifacts, a direction other than the anterior-posterior direction should be selected for phase encoding. To suppress the signal from fat, a frequency-selective pulse should be applied during imaging, or the unenhanced MR imaging data should be subtracted from the contrast-enhanced MR imaging data during postprocessing. The imaging section thickness should be 3 mm or less, the pixel size should be less than 1 mm in each in-plane direction, and the total acquisition time should be less than 2 minutes.
磁共振(MR)成像与乳腺X线摄影和超声检查联合使用时,可成为乳腺成像的有力工具。在各种临床情况下,MR成像可能提供关键信息,从而导致治疗计划的改变(例如,通过显示体格检查或传统成像中隐匿的特征)。尽管许多良性和恶性病变在对比剂增强乳腺MR成像中会强化,但病变的形态特征和动力学曲线有助于缩小鉴别诊断范围。为了优化乳腺MR成像产生的形态学和动力学信息的质量,放射科医生必须注意各种实际和技术前提条件:应使用双侧乳腺线圈,患者采取俯卧位。需要一个具有高场强磁体的MR成像系统,并且磁场在视野范围内必须均匀,视野应包括双侧乳房。应首先应用T2加权序列来识别任何囊肿,然后在静脉注射钆螯合物后,使用T1加权扰相梯度回波序列进行三维成像。为了最小化伪影,应选择前后方向以外的方向进行相位编码。为了抑制脂肪信号,应在成像期间应用频率选择脉冲,或者在后期处理期间从对比增强MR成像数据中减去未增强的MR成像数据。成像层厚应小于或等于3mm,每个平面内方向的像素大小应小于1mm,总采集时间应小于2分钟。