Feasibility of Reduced Radiation Dose and Iodine Load in Lower Extremity Computed Tomography Angiography
JW Park, SS Kim, JH Lee, JH Park
Hong Kong J Radiol 2019;22:172-9
https://doi.org/10.12809/hkjr1916920
Objective: To evaluate the feasibility of reduced radiation dose and low-concentration contrast medium in lower extremity computed tomography angiography (CTA) compared with conventional automatic exposure control CTA.
Methods: A total of 64 subjects underwent dual-source CTA operating in dual-source, high-pitch mode, using both high-concentration contrast medium (group A, n = 31; iomeprol 400 mg I/mL) and low-concentration contrast medium (group B, n = 33; iodixanol 270 mg I/mL). Group A was scanned using a reference tube voltage of 120 kVp and reference 100 mAs under automatic exposure control with iterative reconstruction. Group B was scanned using low tube voltage (80 kVp or 100 kVp if body mass index ≥25 kg/m2) and fixed 120 mAs, along with iterative reconstruction. Images of the two groups were compared regarding attenuation, image noise, signal-to-noise ratio, contrast-to-noise ratio, iodine load, radiation dose, and visual quality assessment (general, enhancement, sharpness, and noise) in various locations of CTA.
Results: The averages of mean attenuation (765.29 ± 146.3 vs. 581.11 ± 163.99 HU), signal-to-noise ratio (42.93 ± 10.85 vs. 30.97 ± 9.54), and contrast-to-noise ratio (39.89 ± 10.53 vs. 27.82 ± 9.12) were significantly higher in group A than in group B (all p < 0.05). Visual quality comparisons in each location were not significantly different.
Conclusion: In lower extremity CTA, reduced radiation dose and iodine load in CTA scans with lowconcentration contrast medium and low tube voltage may not yet be a feasible replacement for conventional automatic exposure control CTA.
Author affiliation(s):
JW Park, SS Kim: Department of Radiology, Chungnam National University Hospital, Chungnam National University School of Medicine, Daejeon, Republic of Korea
JH Lee, JH Park: Division of Cardiology, Department of Internal Medicine, Chungnam National University Hospital, Chungnam National University School of Medicine, Daejeon, Republic of Korea
中文摘要
下肢電腦斷層掃描血管造影中降低輻射劑量和碘負荷的可行性
JW Park、SS Kim、JH Lee、JH Park
目的：評價與常規自動曝光控制電腦斷層掃描血管造影（CTA）相比，下肢CTA降低輻射劑量和低濃度造影劑的可行性。
方法：共64名受試者在雙源大螺距掃描模式下進行CTA，同時使用高濃度造影劑（A組，31例，碘美普爾400 mg I/mL）和低濃度造影劑（B組，33例，碘克沙醇270 mg I/mL）。掃描A組時使用標準管電壓120 kVp和標準管電流100 mAs，並以自動曝光控制結合迭代重建。掃描B組時使用低管電壓（80 kVp，或體重指數≥25 kg/m2時使用100 kVp）和固定管電流120 mAs，同時進行迭代重建。在CTA不同位置比較兩組圖像的衰減值、噪聲、信噪比、對比噪聲比、碘負荷，輻射劑量和視覺質量評估（整體、增強度、銳利度和噪聲）。
結果：A組的平均衰減值（765.29比581.11 HU）、信噪比（42.93比30.97）和對比噪聲比（39.89比27.82）均顯著高於B組（p < 0.05）。每個位置的視覺質量比較沒有顯著差異。
結論：在下肢CTA中使用低濃度造影劑和低管電壓的CTA掃描雖可降低輻射劑量和碘負荷，但仍不能成為傳統自動曝光控制CTA的可行替代方案。