Quantifying lower extremity blood flow using low-dose CT perfusion: validation in a swine model

Area of Science:

• Medical Imaging
• Vascular Physiology
• Radiology

Background:

• Quantitative assessment of peripheral blood flow combined with CT angiography aids risk stratification in vascular disease.
• Accurate measurement of lower extremity blood flow is crucial for managing patients with diverse vascular conditions.

Purpose of the Study:

• To evaluate the reproducibility and accuracy of a low-dose, first-pass analysis CT perfusion technique for measuring lower extremity blood flow.
• To establish CT perfusion as a reliable tool for assessing peripheral vascular disease.

Main Methods:

• Prospective study involving 16 Yorkshire Swine with induced femoral stenosis.
• Lower extremity blood flow measured using CT perfusion and compared against ultrasound flow probes.
• Reproducibility assessed via 33 pairs of CT measurements; accuracy via 43 CT measurements.
• Data analyzed using first-pass analysis model, Mixed model regression, and Bland-Altman analysis.

Main Results:

• CT perfusion measurements closely correlated with ultrasound references (r² = 0.90).
• High reproducibility was observed between sequential CT perfusion measurements (r = 0.97).
• The average effective radiation dose was low, at 2.13 mSv.

Conclusions:

• Low-dose CT perfusion accurately quantifies lower extremity blood flow (mL/min/g) using two helical scans.
• CT angiography combined with perfusion measurements provides a comprehensive assessment of limb ischemia.
• This technique supports both morphological and physiological evaluation of peripheral vascular disease.