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An Optimal Contrast Dose Indicator for the Determination of Hepatic Enhancement in Abdominal Multidetector Computed Tomography: Comparison of Patient Attenuation Indicator With Total Body Weight and Body Mass Index

Li, Jianhai MD*; Udayasankar, Unni K. MD, FRCR*; Tang, Xiangyang PhD*; Carew, John PhD*; Toth, Thomas L. MS; Small, William C. MD, PhD*

Journal of Computer Assisted Tomography: November-December 2010 - Volume 34 - Issue 6 - p 874-878
doi: 10.1097/RCT.0b013e3181ed2f72
Abdominal Imaging

Purpose: 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).

Materials and Methods: 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.

Results: 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/m2 (range, 16.8-43 kg/m2), 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).

Conclusions: 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.

From the *Department of Radiology, Emory University School of Medicine, Atlanta, GA; and †General Electric Healthcare Technology, General Electric Company, Waukesha, WI.

Received for publication March 11, 2010; accepted May 27, 2010.

Reprints: William C. Small, MD, PhD, Department of Radiology, Emory University School of Medicine, 1364 Clifton Rd NE, Atlanta, GA 30322 (e-mail:

The authors have no funding to disclose.

© 2010 Lippincott Williams & Wilkins, Inc.