Boos M, Lentschig M, Scheffler K, Bongartz G M, Steinbrich W
Department of Radiology, University-Hospital, Switzerland.
Invest Radiol. 1998 Sep;33(9):538-46. doi: 10.1097/00004424-199809000-00009.
In this article the relation between contrast medium (CM) application and sequence parameters will be discussed with respect to clinical use of the contrast-enhanced magnetic resonance angiography (CE-MRA) in the peripheral vessel region. The adjustment of the sequence parameters, the CM application timing and the bolus geometry is necessary for an effective use of CE-MRA. Investigation protocols for several vascular regions differ mainly corresponding to varying fields of view and slab thickness. Restrictions of increasing the measurement time are expected in peripherally localized vessels if fast arteriovenous transit time occurs. The vessel contrast depends from (1) optimal CM bolus timing and (2) bolus geometry defined by the parameters of the intravenous bolus injection (flow rate, dose and NaCl flush volume). Our study results have shown that the bolus remains compact but also shorter if a higher flow rate is being applied at equal dose. The enlargement of the NaCl flush volume has evidently caused an increased intraarterial CM concentration and a slightly bolus lengthening. The exact timing regimen requires an automated mechanical CM injection pump. In most countries, a total dose of 0.3 mmol/kg Gd is allowed for application during one investigation. Therefore, obtaining an angiogram of the entire iliac and leg region this total dose must be separated. 0.1 mmol/kg for each of the three measurements can be recommended. Otherwise, using this lower CM dose results in less spatial resolution. At least a dosage of 0.2 mmol/kg Gd is necessary to achieve a higher spatial resolution. The calculation of CM dosage should be also related to the dedicated vessel region of interest than to the body weight only.
在本文中，将围绕外周血管区域对比增强磁共振血管造影（CE-MRA）的临床应用，探讨造影剂（CM）应用与序列参数之间的关系。为有效应用CE-MRA，调整序列参数、CM应用时机和团注形状很有必要。不同血管区域的检查方案主要因视野和层厚的不同而有所差异。如果出现快速动静脉 transit 时间，在外周局部血管中增加测量时间会受到限制。血管对比度取决于（1）最佳CM团注时机和（2）由静脉团注注射参数（流速、剂量和氯化钠冲洗量）定义的团注形状。我们的研究结果表明，在剂量相同的情况下，若应用较高流速，团注会保持紧凑但也会更短。氯化钠冲洗量的增加明显导致动脉内CM浓度升高和团注略有延长。精确的给药方案需要自动机械CM注射泵。在大多数国家，一次检查允许应用的钆总剂量为0.3 mmol/kg。因此，要获得整个髂骨和腿部区域的血管造影，必须将这一总剂量分开。建议每次测量使用0.1 mmol/kg。否则，使用较低的CM剂量会导致空间分辨率降低。至少需要0.2 mmol/kg钆的剂量才能实现更高的空间分辨率。CM剂量的计算也应与特定的感兴趣血管区域相关，而不仅仅与体重相关。
