Department of Radiology, University of Washington, 1959 NE Pacific Street, Box 357115, Seattle, WA, 98195, USA.
Abdom Radiol (NY). 2017 Mar;42(3):759-765. doi: 10.1007/s00261-016-1041-z.
To compare dual-energy computed tomography (DECT) aortography using a 70% reduced iodine dose to single-energy CT (SECT) aortography using a standard iodine dose in the same patient.
Twenty-one patients with a prior SECT aortography using standard iodine dose had DECT aortography using 70% reduced iodine dose. Section 120 kVp images were compared to DECT images reconstructed at both 50 and 77 keV. Reviewers measured image noise and attenuation in the aorta at eight locations from proximal to distal and subjectively scored vascular enhancement on a four-point scale. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. The volume CT dose index (CTDI) for each exam was recorded.
Mean iodine dose was 50 g for SECT and 15 g for DECT (70% reduction). Mean aortic attenuation was similar for section 120 kVp (350 ± 67 HU) and DECT 50 keV (338 ± 57 HU, p = 0.547) but was lower at 77 keV (152 ± 23 HU). Measured image noise was greatest at 50 keV (12 ± 5 HU) and was lowest at 77 keV (7 ± 2 HU, p > 0.001). There was no difference in SNR or CNR between 120 kVp and 50 keV (p > 0.05). Mean subjective vascular enhancement scores for SECT were between good and excellent (3.33-3.69), and for DECT at 50 keV were between moderate and good (2.54-2.93, p < 0.0001). CTDI was 13.6 mGy for SECT and 13.1 mGy for DECT (p = 0.637).
70% Reduced iodine DECT aortography may result in similar aortic attenuation, CNR, SNR, and lower although acceptable subjective image scores when compared to standard iodine SECT aortography in the same patient.
比较同一患者中使用 70%碘剂量降低的双能 CT（DECT）主动脉造影与使用标准碘剂量的单能 CT（SECT）主动脉造影。
21 例先前接受过标准碘剂量 SECT 主动脉造影的患者进行了 70%碘剂量降低的 DECT 主动脉造影。比较了 120 kVp 层厚图像和 50 keV 和 77 keV 重建的 DECT 图像。评估者在从近端到远端的 8 个位置测量主动脉的图像噪声和衰减，并对血管增强进行了 4 分制主观评分。计算了信噪比（SNR）和对比噪声比（CNR）。记录了每次检查的容积 CT 剂量指数（CTDI）。
SECT 的平均碘剂量为 50g，DECT 为 15g（降低了 70%）。120 kVp 层厚的平均主动脉衰减与 DECT 50 keV 相似（350±67 HU），但在 77 keV 时较低（152±23 HU）。在 50 keV 时测量的图像噪声最大（12±5 HU），在 77 keV 时最低（7±2 HU，p>0.001）。120 kVp 与 50 keV 之间的 SNR 或 CNR 无差异（p>0.05）。SECT 的平均主观血管增强评分在良好和优秀之间（3.33-3.69），而 DECT 50 keV 的评分在中等和良好之间（2.54-2.93，p<0.0001）。SECT 的 CTDI 为 13.6 mGy，DECT 为 13.1 mGy（p=0.637）。
与同一患者中使用标准碘剂量 SECT 主动脉造影相比，使用 70%碘剂量降低的 DECT 主动脉造影可能会导致相似的主动脉衰减、CNR、SNR 和较低的（尽管可以接受）主观图像评分。
