Iyer Veena R, Ehman Eric C, Khandelwal Ashish, Wells Michael L, Lee Yong S, Weber Nikkole M, Johnson Matthew P, Yu Lifeng, McCollough Cynthia H, Fletcher Joel G
Department of Radiology, Mayo Clinic, Rochester, MN, USA.
Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN, USA.
Acta Radiol. 2020 Sep;61(9):1186-1195. doi: 10.1177/0284185119898655. Epub 2020 Jan 27.
Low tube potential-high tube current computed tomography (CT) imaging allows reduction in iodine-based contrast dose and may extend the benefit of routine contrast-enhanced CT exams to patients at risk of nephrotoxicity.
To determine the ability of an iodine contrast reduction algorithm to maintain diagnostic image quality for contrast-enhanced abdominal CT.
CT exams with iodine contrast reduction were prescribed for patients at risk for renal dysfunction. The iodine contrast reduction algorithm combines weight-based contrast volume reduction with patient width-based low tube potential selection and bolus-tracking. Control exams with routine iodine dose were selected based on weight, width, and scan protocol. Three radiologists evaluated image quality and diagnostic confidence using a 4-point scale (<2 acceptable). Another radiologist assessed contrast reduction indications and measured portal vein and liver contrast-to-noise ratios.
Forty-six contrast reduction algorithm and control exams were compared (mean creatinine 1.6 vs. 1.2 mg/dL, ≤0.0001). Thirty-nine contrast reduction patients had an eGFR <60 mL/min/1.73m and 15 had single or transplanted kidney. Mean iodine contrast dose was lower in the contrast reduction group (20.9 vs. 39.4 g/mL, <0.0001). Diagnostic confidence was rated as acceptable in 95% (131/138) of contrast reduction and 100% of control exams (1.18-1.28 vs. 1.02-1.13, respectively; >0.06). Liver attenuation and contrast-to-noise ratio (CNR) were similar (=0.08), but portal vein attenuation and CNR were lower with contrast-reduction (mean 176 vs. 198 HU, =0.02; 13 vs. 16, =0.0002).
This size-based contrast reduction algorithm using low kV and bolus tracking reduced iodine contrast dose by 50%, while achieving acceptable image quality in 95% of exams.
低管电压-高管电流计算机断层扫描（CT）成像可减少碘对比剂用量，并可能将常规对比增强CT检查的益处扩展至有肾毒性风险的患者。
确定碘对比剂减少算法在腹部对比增强CT中维持诊断图像质量的能力。
为有肾功能不全风险的患者开具采用碘对比剂减少的CT检查。碘对比剂减少算法将基于体重的对比剂用量减少与基于患者体宽的低管电压选择及团注追踪相结合。根据体重、体宽和扫描方案选择常规碘剂量的对照检查。三名放射科医生使用4分制（<2分为可接受）评估图像质量和诊断信心。另一名放射科医生评估对比剂减少指征，并测量门静脉和肝脏的对比噪声比。
比较了46例对比剂减少算法检查和对照检查（平均肌酐水平分别为1.6和1.2mg/dL，P<0.0001）。39例对比剂减少组患者的估算肾小球滤过率（eGFR）<60mL/min/1.73m²，15例患者为单肾或移植肾。对比剂减少组的平均碘对比剂用量较低（20.9 vs. 39.4g/mL，P<0.0001）。95%（131/138）的对比剂减少检查和100%的对照检查的诊断信心被评为可接受（分别为1.18 - 1.28 vs. 1.02 - 1.13，P>0.06）。肝脏衰减和对比噪声比（CNR）相似（P=0.08），但对比剂减少时门静脉衰减和CNR较低（平均176 vs. 198HU，P=0.02；13 vs. 16，P=0.0002）。
这种基于体型的采用低千伏和团注追踪的对比剂减少算法使碘对比剂用量减少了50%，同时在95%的检查中实现了可接受的图像质量。
