Lung perfusion imaging in small animals using 4D micro-CT at heartbeat temporal resolution.

Area of Science:

• Medical Imaging
• Preclinical Research
• Radiology

Background:

• Quantitative in vivo imaging of lung perfusion in rodents is crucial for preclinical studies.
• Achieving high temporal and spatial resolution simultaneously has been a significant challenge in small animal imaging.
• Existing methods often struggle to provide detailed, real-time perfusion data in small animal models.

Purpose of the Study:

• To demonstrate the utility of 4D micro-CT for quantitative perfusion imaging in rodents.
• To achieve heartbeat temporal resolution and isotropic spatial resolution for enhanced imaging.
• To provide a novel imaging solution for preclinical perfusion studies.

Main Methods:

• Development of a dual tube/detector micro-CT scanner for capturing contrast agent kinetics.
• Utilized a multiple small-volume injection paradigm to reproduce time-density curves.
• Integrated imaging system with microinjector, ventilator, and monitoring applications, controlled by a biological pulse sequence.

Main Results:

• Successfully performed 4D micro-CT imaging of rat lung perfusion with ~150 ms temporal resolution and 88 µm isotropic spatial resolution.
• Demonstrated reproducibility of time-density curves across multiple small injections (50 µL each) with minimal total contrast volume (0.8 mL).
• Reported a radiation dose of 0.16 Gy, comparable to typical micro-CT procedures.

Conclusions:

• 4D micro-CT enables high-resolution, dynamic perfusion imaging in rodents, applicable to various preclinical studies (e.g., tumor perfusion, angiogenesis, renal function).
• The multiple injection paradigm can enhance temporal resolution in dynamic perfusion studies using micro-CT.
• This technique offers a valuable tool for advancing preclinical research requiring detailed perfusion assessment.