Habibi Reza, Krishnam Mayil S, Lohan Derek G, Barkhordarian Fatemeh, Jalili Mehdi, Saleh Roya S, Ruehm Stefan G, Finn J Paul
Department of Radiological Sciences, David Geffen School of Medicine at UCLA, Peter V Ueberroth Bldg, Suite 3371, 10945 Le Conte Ave, Los Angeles, CA 90095, USA.
Radiology. 2008 Aug;248(2):680-92. doi: 10.1148/radiol.2482071505. Epub 2008 Jun 23.
To determine whether contrast material dose reduction at 3.0 T allows preserved image quality for high-spatial-resolution magnetic resonance (MR) angiography of the lower extremities.
Forty-five consecutive patients (27 men, 18 women; mean age, 64 years) underwent contrast material-enhanced MR angiography of the lower extremities at 3.0 T. A waiver of informed consent was granted by the institutional review board. Sixteen patients received high-dose (approximately 0.3 mmol/kg), 15 received intermediate-dose (approximately 0.2 mmol/kg), and 14 received low-dose (approximately 0.1 mmol/kg) gadopentetate dimeglumine during a three-station, dual-injection examination. For scoring purposes, the arterial system from the celiac trunk to the plantar arteries was divided into 34 segments. The images were retrospectively and independently evaluated by two specialized radiologists who were blinded to the patient dose groups. All studies were assessed for overall image quality and the degree of contaminating venous enhancement. Each arterial segment was scored for the quality of vessel definition, the severity of stenoses, and the presence of collateral vessels.
More than 99% of arterial segments were found to be of diagnostic image quality by both readers in all dose groups. Generalized estimating equation analysis showed a significant difference among the three groups with regard to vessel definition (P = .019). No significant difference was found between the high- and intermediate-dose groups; however, the low-dose group had significantly better vessel definition compared with the high-dose (P = .034) and intermediate-dose (P = .015) groups. There was no significant difference among the groups in visualization of collateral vessels. Venous contamination was seen less frequently in the low-dose group, but the difference did not achieve significance.
The study showed that, compared with widely used dose strategies at 1.5 T, the contrast agent dose for 3.0-T lower extremity MR angiography can be reduced multifold without compromising image quality.
确定在3.0 T条件下减少对比剂剂量是否能为下肢高空间分辨率磁共振（MR）血管造影保留图像质量。
45例连续患者（27例男性，18例女性；平均年龄64岁）在3.0 T条件下接受下肢对比剂增强MR血管造影检查。机构审查委员会批准豁免知情同意书。在一次三部位双注射检查中，16例患者接受高剂量（约0.3 mmol/kg），15例接受中等剂量（约0.2 mmol/kg），14例接受低剂量（约0.1 mmol/kg）钆喷酸葡胺。为了评分，将从腹腔干到足底动脉的动脉系统分为34段。由两名对患者剂量分组不知情的专业放射科医生对图像进行回顾性独立评估。对所有研究的整体图像质量和静脉强化污染程度进行评估。对每个动脉段的血管清晰度、狭窄严重程度和侧支血管的存在情况进行评分。
在所有剂量组中，两位阅片者均发现超过99%的动脉段具有诊断图像质量。广义估计方程分析显示，三组在血管清晰度方面存在显著差异（P = .019）。高剂量组和中等剂量组之间未发现显著差异；然而，低剂量组与高剂量组（P = .034）和中等剂量组（P = .015）相比，血管清晰度明显更好。各组在侧支血管显示方面无显著差异。低剂量组静脉污染的出现频率较低，但差异未达到显著水平。
该研究表明，与1.5 T广泛使用的剂量策略相比，3.0 T下肢MR血管造影的对比剂剂量可减少数倍而不影响图像质量。
