Optimization of window settings for virtual monoenergetic imaging in dual-energy CT of the liver: A multi-reader evaluation of standard monoenergetic and advanced imaged-based monoenergetic datasets

Carlo N De Cecco; Damiano Caruso; U Joseph Schoepf; Julian L Wichmann; Janet R Ter Louw; Jonathan D Perry; Melissa M Picard; Amanda R Schaefer; Leland W Parker; Andrew D Hardie

doi:10.1016/j.ejrad.2016.01.007

Optimization of window settings for virtual monoenergetic imaging in dual-energy CT of the liver: A multi-reader evaluation of standard monoenergetic and advanced imaged-based monoenergetic datasets

Eur J Radiol. 2016 Apr;85(4):695-9. doi: 10.1016/j.ejrad.2016.01.007. Epub 2016 Jan 21.

Authors

Affiliations

¹ Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC 29425, United States.
² Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC 29425, United States; Department of Radiological Sciences, Oncological and Pathological Sciences University of Rome "Sapienza", via Franco Faggiana 1668, 04100 Latina, Italy.
³ Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC 29425, United States; Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
⁴ Division of Abdominal Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC 29425, United States.
⁵ Division of Abdominal Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC 29425, United States. Electronic address: andrewdhardie@gmail.com.

PMID: 26971410
DOI: 10.1016/j.ejrad.2016.01.007

Abstract

Objectives: To evaluate optimal window settings for display of virtual monoenergetic reconstructions in third-generation dual-source, dual-energy computed tomography (DECT) of the liver.

Methods: Twenty-nine subjects were prospectively evaluated with DECT in arterial (AP) and portal venous (PVP) phases. Three reconstructed datasets were calculated: standard linearly-blended (LB120), 70-keV standard virtual monoenergetic (M70), and 50-keV advanced image-based virtual monoenergetic (M50+). Two readers assessed optimal window settings (width and level, W/L), establishing a mean for each reconstruction which was used for a blinded assessment of liver lesions.

Results: The optimal W/L for M50+ were significantly higher for both AP (W=429.3 ± 44.6 HU, L=129.4 ± 9.7 HU) and PVP (W=376.1 ± 14.2HU, L=146.6 ± 7.0 HU) than for LB120 (AP, W=215.9 ± 16.9 HU, L=82.3 ± 9.4 HU) (PVP, W=173.4 ± 8.9 HU, L=69.3 ± 6.0 HU) and M70 (AP, W=247.1 ± 22.2 HU, L=72.9 ± 6.8 HU) (PVP, W=232.0 ± 27.9 HU, L=91.6 ± 14.4 HU). Use of the optimal window setting for M50+ vs. LB120 resulted in higher sensitivity (AP, 100% vs. 86%; PVP, 96% vs. 63%).

Conclusions: Application of dedicated window settings results in improved liver lesion detection rates in advanced image-based virtual monoenergetic DECT when customized for arterial and portal venous phases.

Keywords: Dual Energy CT; Hepatocellular carcinoma; Liver; Monoenergetic; Window.

MeSH terms

Female
Humans
Image Processing, Computer-Assisted / methods*
Liver / diagnostic imaging*
Liver Neoplasms / diagnostic imaging*
Male
Middle Aged
Observer Variation
Prospective Studies
Reproducibility of Results
Sensitivity and Specificity
Tomography, X-Ray Computed / methods*