Strong Collision Approximation to Predict Iron Volume Fraction in Ex Vivo Atherosclerotic Rabbits Aorta

Raimo P. Joensuu¹, Louise M A Anderson, ¹², Anna E. Larsson¹, Li-Ming Gan¹, Malin E. Palmr¹, Paul D. Hockings¹

The purpose of this work was to evaluate the suitability of the strong collision approximation to predict the USPIO volume fraction in atherosclerotic rabbits vessel wall from the transverse relaxation time, T2*. There was an excellent agreement (R2 = 0.98) between the theory and the measurements for volume fractions larger than 15 ppm. For lower volume fractions the theory agrees with the measurements poorly. The strong collision model may predict correctly the volume fraction from the T2* map when every voxel contains a relatively high number of magnetic particles but fails if the region contains also voxels with few or no particles.