Multi-parametric imaging of atherosclerotic plaque by 50 MHz ultrasound and 3 Tesla magnetic resonance

This study compares quantitative characterization of plaque by high resolution estimates of ultrasonic attenuation, ultrasonic backscatter and magnetic resonance transverse relaxation time. A total of 54 regions of in vitro human arteries were studied. Backscattered radio frequency signals were acquired with a 50 MHz backscatter acoustic microscope. Ultrasonic parametric images were constructed from the integrated (30 to 50 MHz) backscatter and attenuation obtained using FFT methods with diffraction correction and a multinarrow-band attenuation algorithm. Magnetic resonance images were constructed from estimates of the transverse relaxation time determined by an 8 echo-monoslice sequence at 3 Tesla. Histological segments obtained at each measurement site were used to identify tissue composition. Results suggest that combined ultrasound and magnetic resonance techniques may offer complementary information for plaque characterization.