Reducing iodine load in hepatic CT for patients with chronic liver disease with a combination of low-tube-voltage and adaptive statistical iterative reconstruction

Yoshifumi Noda; Masayuki Kanematsu; Satoshi Goshima; Hiroshi Kondo; Haruo Watanabe; Hiroshi Kawada; Nobuyuki Kawai; Yukichi Tanahashi; Toshiharu R T Miyoshi; Kyongtae T Bae

doi:10.1016/j.ejrad.2014.10.008

Reducing iodine load in hepatic CT for patients with chronic liver disease with a combination of low-tube-voltage and adaptive statistical iterative reconstruction

Eur J Radiol. 2015 Jan;84(1):11-18. doi: 10.1016/j.ejrad.2014.10.008. Epub 2014 Oct 23.

Affiliations

¹ Department of Radiology and Services, Gifu University Hospital, 1-1 Yanagido, Gifu 501-1194, Japan.
² Department of Radiology and Services, Gifu University Hospital, 1-1 Yanagido, Gifu 501-1194, Japan; Department of Radiology Services, Gifu University Hospital, 1-1 Yanagido, Gifu 501-1194, Japan. Electronic address: masa_gif@yahoo.co.jp.
³ Department of Radiology Services, Gifu University Hospital, 1-1 Yanagido, Gifu 501-1194, Japan.
⁴ Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.

PMID: 25455414
DOI: 10.1016/j.ejrad.2014.10.008

Abstract

Purpose: To prospectively assess the effect of reduced iodine load to contrast enhancement, image quality, and detectability of hepatocellular carcinomas (HCCs) in hepatic CT with a combination of 80 kVp tube voltage setting and adaptive statistical iterative reconstruction (ASIR) technique in patients with chronic liver disease.

Materials and methods: This HIPAA-compliant study was approved by our institutional review board and written informed consent was obtained in all patients. During a recent 9-month period, 170 consecutive patients (114 men and 56 women; age range, 40-85 years; mean, 67.7 years) with suspected chronic liver diseases were randomized into three CT groups according to the following iodine-load and tube-voltage protocols: 600 milligram per kilogram body weight (mg/kg) iodine load and 120 peak kilovolt (kVp) tube voltage setting (600-120 group), 500 mg/kg and 80 kVp (500-80 group), and 400mg/kg and 80 kVp (400-80 group). Analysis of variance was conducted to evaluate differences in CT number, background noise, signal-to-noise ratio (SNR), effective dose, HCC-to-liver contrast-to-noise ratio (CNR), and figure of merit (FOM). Sensitivity, specificity, and area under the receiver-operating-characteristic curve (AUC) were compared to assess the detectability of HCCs.

Results: Vascular and hepatic enhancement in the 400-80 and 500-80 groups was comparable to or greater than that in the 600-120 group (P<.05). Subjective image quality was comparable among the three groups. Sensitivity, specificity, and AUC for detecting HCCs were comparable among the groups. The effective dose was kept low (3.3-4.1 mSv) in all three groups.

Conclusion: Iodine load can be reduced by 33% in CT of the liver with a combination of 80 kVp tube voltage setting and ASIR technique, without compromising the contrast enhancement, image quality, and detection of HCCs.

Keywords: Adaptive statistical iterative reconstruction technique; Computed tomography; Contrast material; Liver; Low-tube-voltage.

Publication types

Randomized Controlled Trial

MeSH terms

Adult
Aged
Aged, 80 and over
Carcinoma, Hepatocellular / diagnostic imaging*
Contrast Media*
End Stage Liver Disease / diagnostic imaging*
Female
Humans
Iodine*
Liver Neoplasms / diagnostic imaging*
Male
Middle Aged
Prospective Studies
Radiation Dosage
Radiographic Image Interpretation, Computer-Assisted* / methods
Signal-To-Noise Ratio
Tomography, X-Ray Computed* / methods

Substances

Contrast Media
Iodine