Detreille R, Sauer B, Zabel J P, Batch T, Zhu X, Blum A
Service d'Imagerie Guilloz, CHU Nancy, Av de lattre de Tassigny, 54000 Nancy.
J Radiol. 2007 Jun;88(6):863-9. doi: 10.1016/s0221-0363(07)89887-8.
To determine the influence of 4 independent parameters on signal intensity and density measurements after injection of an arthrography-specific form of gadoterate meglumine and an iodinated contrast material for combined MR and CT arthrography. The parameters included: 1) variations of gadolinium and iodinated contrast agents within the mixture, 2) variations of concentration of the iodinated contrast agent, 3) variation of temperature of the mixture, 4) the type of MR pulse sequence acquired.
The study was performed on a CT using a phantom containing 47 different syringes. Ten separate mixtures of gadolinium and iodinated contrast agents were obtained, each with a 10% change in the respective proportion of each contrast agent. This was repeated 4 times for 4 iodinated contrast agents of different iodine concentration. Two control syringes, 4 mixtures containing 50% normal saline and 50% iodinated contrast material (one for each of the 4 concentrations of iodinated contrast material) and one with a mixture of 50% of normal saline and gadolinium contrast agent. For the MR acquisition, the syringes were separated into 4 groups for 4 phantoms. On a 1.5 T MR unit, SE T1W, FSE T2W, PD and 3D FIESTA sequences were acquired. All acquisitions were repeated 2 times, and a 3 different temperatures.
The progressive increase in the proportion of gadolinium contrast in the solution was associated with a non-linear increase of signal on T1W, 3D FIESTA, and PD images. The signal intensity reached a plateau at concentrations between 40-60%. Signal variations on the 3D FIESTA sequence were significant. On T2W images, there was an increase of measured signal intensity at low gadolinium concentrations. On CT, there was a linear relationship between density measurements and dilution of gadolinium. The progressive increase of the concentration of the iodinated contrast was associated with increased signal loss on MR and progressive increase of density values on CT. Temperature variations were associated with signal intensity changes on T2W and FIESTA images, but not on T1W images.
At 1.5 T, a mixture of 50% iodinated contrast and 50% gadolinium contrast corresponded to an acceptable compromise for combined acquisition of MR and CT arthrography.
确定在注射用于联合磁共振成像（MR）和计算机断层扫描（CT）关节造影的特定形式钆喷酸葡胺和碘化造影剂后，4个独立参数对信号强度和密度测量的影响。这些参数包括：1）混合物中钆和碘化造影剂的变化；2）碘化造影剂浓度的变化；3）混合物温度的变化；4）所采集的MR脉冲序列的类型。
使用含有47个不同注射器的体模在CT上进行研究。获得了钆和碘化造影剂的10种不同混合物，每种造影剂各自的比例有10%的变化。对4种不同碘浓度的碘化造影剂重复此操作4次。两个对照注射器，4种含有50%生理盐水和50%碘化造影剂的混合物（每种碘化造影剂浓度各一种），以及一种含有50%生理盐水和钆造影剂的混合物。对于MR采集，将注射器分为4组用于4个体模。在1.5T MR设备上，采集自旋回波T1加权（SE T1W）、快速自旋回波T2加权（FSE T2W）、质子密度加权（PD）和三维稳态进动快速成像（3D FIESTA）序列。所有采集均重复2次，并在3个不同温度下进行。
溶液中钆造影剂比例的逐渐增加与T1W、3D FIESTA和PD图像上信号的非线性增加相关。信号强度在40% - 60%的浓度之间达到平稳状态。3D FIESTA序列上的信号变化显著。在T2W图像上，低钆浓度时测量的信号强度增加。在CT上，密度测量与钆的稀释之间存在线性关系。碘化造影剂浓度的逐渐增加与MR上信号损失增加以及CT上密度值的逐渐增加相关。温度变化与T2W和FIESTA图像上的信号强度变化相关，但与T1W图像无关。
在1.5T时，50%碘化造影剂和50%钆造影剂的混合物对于联合进行MR和CT关节造影采集而言是一种可接受的折衷方案。
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