Computed tomography with iodine-free contrast media

Area of Science:

• Radiology
• Medical Imaging
• Materials Science

Background:

• Contrast agents are crucial for enhancing visibility in medical imaging.
• Gadolinium (Gd), ytterbium (Yb), and iodine are commonly used elements in contrast media.
• Optimizing contrast agent performance is essential for diagnostic accuracy.

Purpose of the Study:

• To evaluate and compare the in vitro and in vivo enhancement properties of different concentrations of gadolinium (Gd), ytterbium (Yb), and iodine-based contrast agents.
• To assess the impact of varying concentrations and X-ray tube potentials (kVp) on contrast enhancement.
• To compare the performance of Gd and Yb with traditional iodine contrast agents in dynamic CT studies.

Main Methods:

• In vitro studies comparing enhancement (HU) of Gd, Yb, and iodine across concentrations from 0.1 to 30 mg/ml at 120 kVp and 137 kVp.
• In vivo dynamic CT studies in ten dogs using 0.5 M Gd, Yb, and iodine contrast agents.
• Acquisition of time-density curves in the aorta and liver to quantify contrast enhancement.

Main Results:

• In vitro enhancement order: Gd (120 kVp) > Gd (137 kVp) > Yb (120 kVp) > Yb (137 kVp) > iodine (120 kVp) > iodine (137 kVp).
• Specific in vitro enhancement: Gd (40.8 HU at 120 kVp), Yb (34.2 HU), iodine (29.6 HU).
• In vivo liver enhancement: Gd (21 HU) > Yb (19 HU) > iodine (12 HU). Aortal enhancement: Gd and Yb (190 HU) > iodine (157 HU).
• All contrast media were well tolerated.

Conclusions:

• Equimolar concentrations of Gd and Yb demonstrate superior in vitro contrast and enhancement compared to iodine.
• Gd and Yb contrast agents offer higher enhancement in both liver and aorta compared to iodine in dynamic CT studies.
• Gd and Yb represent promising alternatives to iodine-based contrast agents for CT imaging, potentially improving diagnostic capabilities.