Shuman William P, Chan Keith T, Busey Janet M, Mitsumori Lee M, Koprowicz Kent M
Department of Radiology, University of Washington School of Medicine, Box 357115, 1959 NE Pacific Street, Seattle, WA 98195.
Department of Radiology, University of Washington School of Medicine, Box 357115, 1959 NE Pacific Street, Seattle, WA 98195.
Acad Radiol. 2016 May;23(5):611-8. doi: 10.1016/j.acra.2015.12.019. Epub 2016 Feb 17.
Because many patients with aortic pathology also have compromised renal function, we wished to investigate dual-energy computed tomography (DECT) aortography with 50% reduced iodine dose compared to single-energy computed tomography (SECT) aortography with standard iodine dose.
Fifty patients had DECT aortography with 50% reduced iodine dose. Thirty-four of these patients had prior SECT aortography with standard iodine dose. DECT images were reconstructed at both 50 and 77 keV and were compared to SECT 120 kVp images. Reviewers measured aortic attenuation, image noise, and scored vascular enhancement. Signal-to-noise ratios (SNR) and contrast-to-noise ratios (CNR) were calculated. Volume CT dose index was recorded.
Mean iodine dose was 47 g for SECT and 24 g for DECT. Aortic attenuation was highest at reduced iodine dose DECT 50 keV (570 ± 105 Hounsfield units [HU]) compared to 77 keV (239 ± 40 HU) or to standard iodine dose SECT 120 kVp (356 ± 69 HU) (P < 0.05). Image noise was greatest at 50 keV compared to 77 keV and 120 kVp (P < 0.05) but was similar between 77 keV and 120 kVp (P > 0.05). SNR and CNR were the same at 50 keV and 120 kVp (P > 0.05). Mean vascular enhancement scores were all above 3.0 (good, typical enhancement). Volume CT dose index was 11.7 mGy for DECT and 11.8 mGy for SECT (P = 0.37).
DECT aortography with 50% reduced iodine reconstructed at 50 keV resulted in significantly greater aortic attenuation, good subjective vascular enhancement, and comparable SNR and CNR compared to standard iodine dose SECT. DECT image noise at 77 keV was similar to SECT at 120 kVp.
由于许多患有主动脉病变的患者肾功能也受损，我们希望研究与使用标准碘剂量的单能量计算机断层扫描（SECT）主动脉造影相比，碘剂量降低50%的双能量计算机断层扫描（DECT）主动脉造影。
50例患者接受了碘剂量降低50%的DECT主动脉造影。其中34例患者之前接受过标准碘剂量的SECT主动脉造影。DECT图像在50 keV和77 keV下重建，并与SECT 120 kVp图像进行比较。阅片者测量主动脉衰减、图像噪声，并对血管强化进行评分。计算信噪比（SNR）和对比噪声比（CNR）。记录容积CT剂量指数。
SECT的平均碘剂量为47 g，DECT为24 g。与77 keV（239±40亨氏单位[HU]）或标准碘剂量SECT 120 kVp（356±69 HU）相比，在碘剂量降低的DECT 50 keV下主动脉衰减最高（570±105 HU）（P<0.05）。与77 keV和120 kVp相比，50 keV时图像噪声最大（P<0.05），但77 keV和120 kVp之间相似（P>0.05）。50 keV和120 kVp时SNR和CNR相同（P>0.05）。平均血管强化评分均高于3.0（良好，典型强化）。DECT的容积CT剂量指数为11.7 mGy，SECT为11.8 mGy（P = 0.37）。
与标准碘剂量SECT相比，在50 keV下重建的碘剂量降低50%的DECT主动脉造影导致主动脉衰减显著增加，主观血管强化良好，SNR和CNR相当。77 keV时的DECT图像噪声与120 kVp时的SECT相似。
