Quantitative analysis of iodine enhancement

A 77 year-old male was examined and was found to have several liver lesions. Dual-energy CT was used to assess the level of iodine enhancement in each lesion.

Method

A contrast-enhanced DECT study was performed using a Philips iCT 256-slice CT scanner. The images were reconstructed using the iDose⁴ iterative reconstruction technique (Figure 1a and b), and were assessed using the Spectral Analysis application (extended Brilliance Workspace version 4.5, Philips Healthcare). Regions of interest (ROIs) were placed in two lesions and a visually homogenous region of liver parenchyma, and dual-energy analysis was performed.

 

• Axial scan mode
• iDose⁴ Level 4
• 80 / 140 kVp
• 460 / 90 mAs 
• 2.5 mm slice thickness
• 0.5 second rotation speed 
• 64 × 0.625 mm collimation
• 75.2 mGy × cm DLP
• (32cm) 9.4 x 2 mGy CTDI_vol
• 1.13 mSv effective dose

Quantitative analysis of iodine enhancement was performed on the dual-energy data in delayed phase images relative to liver parenchyma (Figure 2a and 2b). One lesion (ROI 2 in Figure 2a and 2b) demonstrated washout in the delayed enhancement phase, subsequent to early enhancement in the arterial phase. The other lesion (ROI 1 in Figure 2a and 2b) demonstrated central hypoenhancement in the delayed phase and other phases. The use of the iDose⁴ iterative reconstruction technique reduced image noise and allowed greater detail to be seen in the quantitative analysis (Figure 3).

Quantitative analysis of the iodine enhancement was demonstrated using a combination of dual-energy CT acquisition and an iterative reconstruction technique. The advanced technologies of the iCT, in combination with iDose⁴, allow imaging at low dose with high image quality.