Experimental assessment of diffusible iodine-based contrast-enhanced computed tomography (diceCT) protocols

Area of Science:

• Comparative anatomy
• Radiological imaging
• Digital morphology

Background:

• Diffusible iodine-based contrast-enhanced computed tomography (diceCT) enhances soft tissue contrast in CT imaging.
• Current diceCT protocols are primarily optimized for specimens under 1 kg.
• Standardized protocols for larger specimens (above 1 kg) are lacking.

Purpose of the Study:

• To experimentally assess diceCT protocol efficacy for whole-body specimens weighing 1-4.5 kg.
• To determine the impact of Lugol's iodine concentration, duration, and specimen preparation on imaging outcomes.
• To quantify soft tissue radiodensity and volumetric changes over time.

Main Methods:

• Sequential CT imaging of Australian brushtail possums (1-4.5 kg) over 8 weeks.
• Varied Lugol's iodine concentration, presence/absence of skin, solution volume, and agitation.
• Weekly monitoring of tissue radiodensities and quantification of volumetric changes.

Main Results:

• Significant soft tissue radiodensity and volume changes occurred within the first 28 days of Lugol's iodine treatment.
• Skinning larger specimens offered negligible benefit for solution diffusion.
• High Lugol's iodine concentrations (10%) and long exposure (beyond 5 weeks) caused significant soft tissue volumetric changes.

Conclusions:

• Established diceCT protocols are effective for larger specimens (1-4.5 kg).
• Optimized protocols should consider a treatment duration under 5 weeks to mitigate volumetric distortion.
• Findings guide diceCT protocol design for mammalian specimens over 1 kg.