Background

The contrast agent (CA) dose for abdominal computed tomography (CT) is typically based on patient total body weight (TBW), ignoring adipose tissue distribution. We report on our experience of dosing according to the lean body weight (LBW).

Methods

After Ethics Committee approval, we retrospectively screened 219 consecutive patients, 18 being excluded for not matching the inclusion criteria. Thus, 201 were analysed (106 males), all undergoing a contrast-enhanced abdominal CT with iopamidol (370 mgI/mL) or iomeprol (400 mgI/mL). LBW was estimated using validated formulas. Liver contrast-enhancement (CE_L) was measured. Data were reported as mean ± standard deviation. Pearson correlation coefficient, ANOVA, and the Levene test were used.

Results

Mean age was 66 ± 13 years, TBW 72 ± 15 kg, LBW 53 ± 11 kg, and LBW/TBW ratio 74 ± 8%; body mass index was 26 ± 5 kg/m², with 9 underweight patients (4%), 82 normal weight (41%), 76 overweight (38%), and 34 obese (17%). The administered CA dose was 0.46 ± 0.06 gI/kg of TBW, corresponding to 0.63 ± 0.09 gI/kg of LBW. A negative correlation was found between TBW and CA dose (r = -0.683, p < 0.001). CE_L (Hounsfield units) was 51 ± 18 in underweight patients, 44 ± 8 in normal weight, 42 ± 9 in overweight, and 40 ± 6 in obese, with a significant difference for both mean (p = 0.004) and variance (p < 0.001). A low but significant positive correlation was found between CE_L and CA dose in gI per TBW (r = 0.371, p < 0.001) or per LBW (r = 0.333, p < 0.001).

Conclusions

The injected CA dose was highly variable, with obese patients receiving a lower dose than underweight patients, as a radiologist-driven ‘compensation effect’. Diagnostic abdomen CT examinations may be obtained using 0.63 gI/kg of LBW.

中文翻译：

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腹部CT：放射线学家对碘化造影剂剂量的调整接近每瘦体重的计算值。

背景

用于腹部计算机断层扫描（CT）的造影剂（CA）剂量通常基于患者的总体重（TBW），而忽略了脂肪组织的分布。我们报告根据瘦体重（LBW）进行给药的经验。

方法

在伦理委员会批准之后，我们回顾性筛选了219位连续患者，其中18例因不符合纳入标准而被排除在外。因此，分析了201位患者（106位男性），所有患者均接受了造影剂增强的腹部CT与碘帕醇（370 mgI / mL）或碘美普尔（400 mgI / mL）的对比。LBW是使用经过验证的公式估算的。测量了肝脏的对比度增强（CE _L）。数据报告为平均值±标准偏差。使用皮尔逊相关系数，ANOVA和Levene检验。

结果

平均年龄为66±13岁，TBW 72±15公斤，LBW 53±11公斤，LBW / TBW比率74±8％; 体重指数为26±5 kg / m ²，其中9例体重不足患者（4％），82正常体重（41％），76体重超重（38％）和34肥胖（17％）。施用的CA剂量为0.46±0.06 gI / kg TBW，相当于0.63±0.09 gI / kg LBW。发现TBW和CA剂量之间呈负相关（r  = -0.683，p  <0.001）。体重不足患者的CE _L（Hounsfield单位）为51±18，正常体重为44±8，超重为42±9，肥胖为40±6，均值（p  = 0.004）和方差（p  <0.001）。CE _L之间发现低但显着的正相关和CA剂量，单位为TBW（r  = 0.371，p  <0.001）或每LBW（r  = 0.333，p  <0.001）。

结论

注射的CA剂量变化很大，肥胖的患者接受的剂量比体重不足的患者要低，这是放射科医生驱动的“补偿作用”。可以使用0.63 gI / kg的LBW获得腹部CT诊断检查。