Balakrishnan Asha, Kacher Daniel F, Gombos Eva, Smith Darrell N, Carretero Macarena, Leon Bill, Freyre Carlos V, Chavoustie Steven E
Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
J Magn Reson Imaging. 2009 Aug;30(2):430-6. doi: 10.1002/jmri.21796.
To investigate the effect of a negative pressure fixation device on misregistration artifacts in contrast-enhanced (CE) MR subtraction images.
Nine patients, two of which had been previously diagnosed with breast cancer, were examined with T2-weighted (T2-w) turbo spin-echo (TSE) and three-dimensional (3D) spoiled gradient-recalled echo (SPGR) CE dynamic MRI. Baselines images were subtracted from the dynamic images. A device consisting of two stiff plastic domes was placed on the breasts of each patient. Negative pressure of 27 to 37 mmHg within the domes was maintained. The patient was positioned prone in the coil without the device and imaged as a baseline. Subsequently, the patient was placed into the negative pressure domes and reimaged. One of the nine patients was also imaged supine to establish feasibility for this positioning.
With the use of the negative pressure fixation device, a reduction in misregistration artifact has been demonstrated in prone imaging. Patients reported improved comfort with the device and feasibility has been shown for supine imaging.
The device was shown to be MRI-compatible and successfully applied in this pilot study, opening other avenues of exploration. Supine positioning for breast imaging makes possible better access for biopsy and intervention. Further modifications to the device are in order for this purpose and to eliminate motion due to breathing in the prone position.
探讨负压固定装置对对比增强(CE)磁共振减影图像中配准错误伪影的影响。
对9例患者进行了检查,其中2例先前已被诊断为乳腺癌,采用T2加权(T2-w)快速自旋回波(TSE)和三维(3D)扰相梯度回波(SPGR)CE动态磁共振成像。从动态图像中减去基线图像。在每位患者的乳房上放置一个由两个硬质塑料穹顶组成的装置。在穹顶内维持27至37 mmHg的负压。患者在没有该装置的情况下俯卧于线圈中成像作为基线。随后,将患者置于负压穹顶中并再次成像。9例患者中的1例也进行了仰卧位成像以确定该体位的可行性。
使用负压固定装置后,俯卧位成像中配准错误伪影有所减少。患者报告使用该装置时舒适度有所提高,并且仰卧位成像的可行性也已得到证实。
该装置在本初步研究中显示与MRI兼容且成功应用,开辟了其他探索途径。乳房成像的仰卧位可使活检和干预更容易进行。为此目的以及消除俯卧位时因呼吸引起的运动,需要对该装置进行进一步改进。