Chen Chien-Ming, Chu Sung-Yu, Hsu Ming-Yi, Liao Ying-Lan, Tsai Hui-Yu
Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital Linkou, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
Eur Radiol. 2014 Feb;24(2):460-8. doi: 10.1007/s00330-013-3027-3. Epub 2013 Oct 2.
To evaluate CT aortography at reduced tube voltage and contrast medium dose while maintaining image quality through iterative reconstruction (IR).
The Institutional Review Board approved a prospective study of 48 patients who underwent follow-up CT aortography. We performed intra-individual comparisons of arterial phase images using 120 kVp (standard tube voltage) and 80 kVp (low tube voltage). Low-tube-voltage imaging was performed on a 320-detector CT with IR following injection of 40 ml of contrast medium. We assessed aortic attenuation, aortic attenuation gradient, image noise, contrast-to-noise ratio (CNR), volume CT dose index (CTDIvol), and figure of merit (FOM) of image noise and CNR. Two readers assessed images for diagnostic quality, image noise, and artefacts.
The low-tube-voltage protocol showed 23-31% higher mean aortic attenuation and image noise (both P < 0.01) than the standard-tube-voltage protocol, but no significant difference in the CNR and aortic attenuation gradients. The low-tube-voltage protocol showed a 48% reduction in CTDIvol and an 80% increase in FOM of CNR. Subjective diagnostic quality was similar for both protocols, but low-tube-voltage images showed greater image noise (P = 0.01).
Application of IR to an 80-kVp CT aortography protocol allows radiation dose and contrast medium reduction without affecting image quality.
• CT aortography at 80 kVp allows a significant reduction in radiation dose. • Addition of iterative reconstruction reduces image noise and improves image quality. • The injected contrast medium dose can be substantially reduced at 80 kVp. • Aortic enhancement is uniform despite a reduced volume of contrast medium.
评估在降低管电压和造影剂剂量的情况下，通过迭代重建（IR）维持图像质量的CT主动脉造影。
机构审查委员会批准了一项对48例行随访CT主动脉造影患者的前瞻性研究。我们对使用120 kVp（标准管电压）和80 kVp（低管电压）获得的动脉期图像进行个体内比较。低管电压成像在320排CT上进行，注射40 ml造影剂后采用IR。我们评估了主动脉衰减、主动脉衰减梯度、图像噪声、对比噪声比（CNR）、容积CT剂量指数（CTDIvol）以及图像噪声和CNR的优值（FOM）。两名阅片者评估图像的诊断质量、图像噪声和伪影。
低管电压方案显示平均主动脉衰减和图像噪声比标准管电压方案高23% - 31%（均P < 0.01），但CNR和主动脉衰减梯度无显著差异。低管电压方案显示CTDIvol降低48%，CNR的FOM增加80%。两种方案的主观诊断质量相似，但低管电压图像的图像噪声更大（P = 0.01）。
将IR应用于80 kVp的CT主动脉造影方案可降低辐射剂量和造影剂用量，且不影响图像质量。
• 80 kVp下的CT主动脉造影可显著降低辐射剂量。• 添加迭代重建可降低图像噪声并提高图像质量。• 80 kVp时可大幅降低注射的造影剂剂量。• 尽管造影剂用量减少，但主动脉强化均匀。
