Li Jianhai, Udayasankar Unni K, Tang Xiangyang, Carew John, Toth Thomas L, Small William C
Department of Radiology, Emory University School of Medicine, Atlanta, GA 30322, USA.
J Comput Assist Tomogr. 2010 Nov-Dec;34(6):874-8. doi: 10.1097/RCT.0b013e3181ed2f72.
To evaluate a patient attenuation indicator (PAI) as compared with traditional patient-related factors of total body weight and body mass index (BMI) as a predictor of hepatic enhancement in contrast-enhanced abdominal multidetector computed tomography (MDCT).
Institutional review board approval was obtained, and the study was Health Insurance Portability and Accountability Act compliant. A total of 77 patients (mean age, 53 years; male-female ratio, 32:45) underwent routine contrast-enhanced abdominal CT on a 16-slice multidetector CT (LightSpeed 16; GE Medical Systems, Milwaukee, Wis). Contrast enhancement was achieved by administering a 120-mL iodine contrast medium (350-mg iodine per milliliter) at an injection rate of 3 mL/s followed by an injection of 40-mL saline at 3 mL/s. Computed tomographic attenuation values (Hounsfield units [HU]) of liver parenchyma, main portal vein, and abdominal aorta were measured in each patient. Statistical analysis was performed with linear regression to determine the correlation of PAI, total body weight, and BMI with abdominal organ enhancement.
The mean of PAI, total body weight, and BMI were 28.0 (range, 22.1-34.2), 79.0 kg (range, 49.6-112.2 kg), and 27.5 kg/m (range, 16.8-43 kg/m), respectively. Mean hepatic enhancement was 128.2 HU (range, 73.6-175 HU), mean main portal vein enhancement was 214.2 HU (range, 118-327 HU), and mean abdominal aorta enhancement was 208.9 HU (range, 116-395 HU). Patient attenuation indicator, total body weight, and BMI showed a negative correlation with liver enhancement (r = -0.55, r = -0.4, and r = -0.3, respectively). Patient attenuation indicator exhibited a significantly higher correlation with hepatic enhancement than total body weight and BMI (P < 0.01, respectively).
Patient attenuation indicator exhibits a moderately inverse correlation with liver enhancement that is greater than those of total body weight and BMI. Patient attenuation indicator may be reliable in predicting the hepatic enhancement degree for a given dose of contrast material and has a potential use in customizing individual patient contrast medium dose during contrast-enhanced abdominal CT.
评估患者衰减指标（PAI）与传统的与患者相关的因素（总体重和体重指数[BMI]）相比，作为腹部多排螺旋计算机断层扫描（MDCT）增强扫描中肝脏强化的预测指标。
获得机构审查委员会批准，且该研究符合《健康保险流通与责任法案》。共有77例患者（平均年龄53岁；男女比例为32:45）在16排多排螺旋CT（LightSpeed 16；GE医疗系统公司，威斯康星州密尔沃基）上接受常规腹部增强CT检查。通过以3 mL/s的注射速率注入120 mL碘造影剂（每毫升含350 mg碘），随后以3 mL/s的速率注入40 mL生理盐水来实现增强扫描。测量每位患者肝实质、主门静脉和腹主动脉的计算机断层扫描衰减值（亨氏单位[HU]）。采用线性回归进行统计分析，以确定PAI、总体重和BMI与腹部器官强化之间的相关性。
PAI、总体重和BMI的平均值分别为28.0（范围22.1 - 34.2）、79.0 kg（范围49.6 - 112.2 kg）和27.5 kg/m²（范围16.8 - 43 kg/m²）。平均肝脏强化为128.2 HU（范围73.6 - 175 HU），平均主门静脉强化为214.2 HU（范围118 - 327 HU），平均腹主动脉强化为208.9 HU（范围116 - 395 HU）。患者衰减指标、总体重和BMI与肝脏强化呈负相关（r分别为 - 0.55、 - 0.4和 - 0.3）。患者衰减指标与肝脏强化的相关性显著高于总体重和BMI（P均<0.01）。
患者衰减指标与肝脏强化呈中度负相关，且大于总体重和BMI与肝脏强化的相关性。患者衰减指标在预测给定剂量造影剂下的肝脏强化程度方面可能是可靠的，并且在腹部增强CT中为个体患者定制造影剂剂量方面具有潜在用途。
