Korean J Radiol.  2012 Aug;13(4):434-442. 10.3348/kjr.2012.13.4.434.

Spectral CT: Preliminary Studies in the Liver Cirrhosis

• Lv P
• Lin X
• Gao J
• Chen K

• KMID: 1383855
• DOI: http://doi.org/10.3348/kjr.2012.13.4.434

Abstract

OBJECTIVE
To investigate the value of spectral CT imaging in the diagnosis and classification of liver cirrhosis during the arterial phase (AP) and portal venous phase (PVP).
MATERIALS AND METHODS
Thirty-eight patients with liver cirrhosis (Child-Pugh class A/B/C: n = 10/14/14), and 43 patients with healthy livers, participated in this study. The researchers used abdominal spectral CT imaging during AP and PVP. Iodine concentration, derived from the iodine-based material-decomposition image and the iodine concentration ratio (ICratio) between AP and PVP, were obtained. Statistical analyses {two-sample t test, One-factor analysis of variance, and area under the receiver operating characteristic curve (A [z])} were performed.
RESULTS
The mean normalized iodine concentration (NIC) (0.5 +/- 0.12) during PVP in the control group was significantly higher than that in the study group (0.4 +/- 0.10 on average, 0.4 +/- 0.08 for Class A, 0.4 +/- 0.15 for Class B, and 0.4 +/- 0.06 for Class C) (All p < 0.05). Within the cirrhotic liver group, the mean NIC for Class C during the AP (0.1 +/- 0.05) was significantly higher than NICs for Classes A (0.1 +/- 0.06) and B (0.1 +/- 0.03) (Both p < 0.05). The ICratio in the study group (0.4 +/- 0.15), especially for Class C (0.5 +/- 0.14), was higher than that in the control group (0.3 +/- 0.15) (p < 0.05).The combination of NIC and ICratio showed high sensitivity and specificity for differentiating healthy liver from cirrhotic liver, especially in Class C cirrhotic liver.
CONCLUSION
Spectral CT Provides a quantitative method with which to analyze the cirrhotic liver, and shows the potential value in the classification of liver cirrhosis.

Keyword

Spectral CT; Dual-energy CT; Liver cirrhosis; Iodine concentration; Material decomposition

MeSH Terms

Analysis of Variance
Case-Control Studies
Contrast Media/diagnostic use
Female
Humans
Liver/pathology
Liver Cirrhosis/pathology/*radiography
Male
Middle Aged
Prospective Studies
ROC Curve
Sensitivity and Specificity
Tomography, X-Ray Computed/*methods
Triiodobenzoic Acids/diagnostic use

Figure

• 

  Fig. 1 Distribution of 16 tubes with different concentrations of iodine solution.Arrangement of 16 tubes (A, B) containing iodine solutions with different concentrations (0 to 30.0 mg/mL) at transverse monochromatic CT image obtained at 65-keV energy level.

• 

  Fig. 2 Graph illustrates relationship between actual (x-axis) and measured (y-axis) iodine (I) concentrations in in vitro experiment. Test tubes filled with known iodine concentrations of 0.3-30.0 mg/mm3 were scanned with CT spectral imaging, and iodine concentrations were measured from iodine-based material-decomposition images. Mean and standard deviations for three separate measurements for same iodine concentration in each test tube (n = 13) are shown. Fitted line shows linear relationship between measured and actual concentrations.

• 

  Fig. 3 Monochromatic and material decomposition images of cirrhosis.Transverse (A, D) monochromatic CT image obtained at 70-keV energy level and (B, E) iodine-based and (C, F) water-based material-decomposition images obtained from single spectral CT acquisition (section thickness, 1.25 mm) in 63-year-old woman with cirrhosis B during AP and PVP respectively. AP = arterial phase, PVP = portal venous phase

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