Coolen Bram F, Poot Dirk H J, Liem Madieke I, Smits Loek P, Gao Shan, Kotek Gyula, Klein Stefan, Nederveen Aart J
Department of Radiology, Academic Medical Center, Amsterdam, the Netherlands.
Biomedical Imaging Group Rotterdam, Depts. of Radiology and Medical Informatics, Erasmus Medical Center, Rotterdam, the Netherlands.
Magn Reson Med. 2016 Mar;75(3):1008-17. doi: 10.1002/mrm.25634. Epub 2015 Apr 28.
A novel three-dimensional (3D) T1 and T2 mapping protocol for the carotid artery is presented.
A 3D black-blood imaging sequence was adapted allowing carotid T1 and T2 mapping using multiple flip angles and echo time (TE) preparation times. B1 mapping was performed to correct for spatially varying deviations from the nominal flip angle. The protocol was optimized using simulations and phantom experiments. In vivo scans were performed on six healthy volunteers in two sessions, and in a patient with advanced atherosclerosis. Compensation for patient motion was achieved by 3D registration of the inter/intrasession scans. Subsequently, T1 and T2 maps were obtained by maximum likelihood estimation.
Simulations and phantom experiments showed that the bias in T1 and T2 estimation was < 10% within the range of physiological values. In vivo T1 and T2 values for carotid vessel wall were 844 ± 96 and 39 ± 5 ms, with good repeatability across scans. Patient data revealed altered T1 and T2 values in regions of atherosclerotic plaque.
The 3D T1 and T2 mapping of the carotid artery is feasible using variable flip angle and variable TE preparation acquisitions. We foresee application of this technique for plaque characterization and monitoring plaque progression in atherosclerotic patients.
提出一种用于颈动脉的新型三维（3D）T1和T2映射协议。
采用一种3D黑血成像序列，通过多个翻转角和回波时间（TE）准备时间实现颈动脉T1和T2映射。进行B1映射以校正与标称翻转角的空间变化偏差。该协议通过模拟和体模实验进行了优化。对6名健康志愿者进行了两次体内扫描，并对一名患有晚期动脉粥样硬化的患者进行了扫描。通过对不同扫描间/扫描内的扫描进行3D配准来补偿患者运动。随后，通过最大似然估计获得T1和T2映射。
模拟和体模实验表明，在生理值范围内，T1和T2估计的偏差<10%。颈动脉血管壁的体内T1和T2值分别为844±96和39±5毫秒，扫描间具有良好的重复性。患者数据显示动脉粥样硬化斑块区域的T1和T2值发生了改变。
使用可变翻转角和可变TE准备采集对颈动脉进行3D T1和T2映射是可行的。我们预见该技术可用于动脉粥样硬化患者的斑块特征描述和监测斑块进展。
