Yanaga Yumi, Awai Kazuo, Nakaura Takeshi, Oda Seitaro, Funama Yoshinori, Bae Kyongtae T, Yamashita Yasuyuki
Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan.
AJR Am J Roentgenol. 2009 Apr;192(4):1071-8. doi: 10.2214/AJR.08.1407.
The objective of our study was to investigate the effect on aortic enhancement of iodine doses adjusted for the patient estimated lean body weight (LBW) at CT angiography (CTA).
CTA for the whole aorta using a 64-MDCT scanner was performed in 97 patients (mean age, 67.4 years) with confirmed or suspected aortoiliac disease. The patients were divided into two groups: a total body weight (TBW) group (n = 49) and an estimated LBW group (n = 48). LBW was estimated from the patient weight (TBW) and height. The TBW and estimated LBW groups received 360 mg I/kg of TBW and 450 mg I/kg of estimated LBW of contrast medium, respectively. The relative dose ratio for the estimated LBW group versus the TBW group was based on the fact that the standard percentage of body fat in Japanese adults with an average TBW of 60 kg is 20% (360 = 0.8 x 450). Differences in the degree of aortic enhancement and interpatient variability in aortic enhancement between the estimated LBW and TBW group were evaluated.
Mean aortic enhancement was 308.9 HU for the estimated LBW group and 314.1 HU for the TBW group, indicating no significant difference in the degree of enhancement (Welch's t test, p = 0.61). The interquartile range was smaller for the LBW group than the TBW group (52.8 vs 79.1 HU, respectively); interpatient variability was lower in the estimated LBW group. The aortic attenuation gradient in the TBW group and estimated LBW group was 20.7 and 25.8 HU, respectively; the difference was not statistically significant.
The CTA protocol using an estimated LBW-tailored dose yielded more consistent aortic enhancement with reduced interpatient variability than the CTA protocol using a TBW-based dose.
我们研究的目的是探讨在CT血管造影（CTA）中，根据患者估计的瘦体重（LBW）调整碘剂量对主动脉强化的影响。
使用64排MDCT扫描仪对97例确诊或疑似主髂动脉疾病的患者（平均年龄67.4岁）进行全主动脉CTA检查。患者分为两组：总体重（TBW）组（n = 49）和估计LBW组（n = 48）。根据患者体重（TBW）和身高估算LBW。TBW组和估计LBW组分别接受360 mg I/kg TBW和450 mg I/kg估计LBW的造影剂。估计LBW组与TBW组的相对剂量比基于日本平均TBW为60 kg的成年人的标准体脂百分比为20%这一事实（360 = 0.8×450）。评估估计LBW组和TBW组之间主动脉强化程度的差异以及患者间主动脉强化的变异性。
估计LBW组的平均主动脉强化为308.9 HU，TBW组为314.1 HU，表明强化程度无显著差异（韦尔奇t检验，p = 0.61）。LBW组的四分位间距小于TBW组（分别为52.8与79.1 HU）；估计LBW组的患者间变异性较低。TBW组和估计LBW组的主动脉衰减梯度分别为20.7和25.8 HU；差异无统计学意义。
与使用基于TBW的剂量的CTA方案相比，使用根据估计LBW定制剂量的CTA方案可产生更一致的主动脉强化，且患者间变异性降低。
