Simultaneous T₁ and T₂ mapping of the carotid plaque (SIMPLE) with T₂ and inversion recovery prepared 3D radial imaging

Purpose To propose a technique that can produce different T 1 and T 2 contrasts in a single scan for simultaneous T 1 and T 2 mapping of the carotid plaque (SIMPLE). Methods An interleaved 3D golden angle radial trajectory was used in conjunction with T 2 preparation with variable duration (TE prep ) and inversion recovery pulses. Sliding window reconstruction was adopted to reconstruct images at different inversion delay time and TE prep for joint T 1 and T 2 fitting. In the fitting procedure, a rapid B 1 correction method was presented. The accuracy of SIMPLE was investigated in phantom experiments. In vivo scans were performed on 5 healthy volunteers with 2 scans each, and on 5 patients with carotid atherosclerosis. Results The phantom T 1 and T 2 estimations of SIMPLE agreed well with the standard methods with the percentage difference smaller than 7.1%. In vivo T 1 and T 2 for normal carotid vessel wall were 1213 ± 48.3 ms and 51.1 ± 1.7 ms, with good interscan repeatability. Alternations of T 1 and T 2 in plaque regions were in agreement with the conventional multicontrast imaging findings. Conclusion The proposed SIMPLE allows simultaneous T 1 and T 2 mapping of the carotid artery in less than 10 minutes, serving as a quantitative tool with good accuracy and reproducibility for plaque characterization.