Proton relaxation times in arterial wall and atheromatous lesions in man

The proton relaxation times of autopsy samples of arterial intima-media were measured with an NMR spectrometer and results correlated to the microscopically estimated lipid content of the vascular wall. The normal arterial intima-media contained two T1 relaxation components. The short T1 component (T1s) was 90 +/- 13 ms and its relative weight was 11%. The long T1 component (T1l) was 523 +/- 89 ms and relative weight 88%, respectively. The average T2 was 99 +/- 18 ms. In diseased vessels, a positive correlation was found between the lipid content of the vessel wall and the relaxation rate of the fast component. T1s of the intima-media was significantly shorter (P less than .01) in severe atheromatosis compared with vessels without fat deposition. The results suggest that atheromatous lesions should be best highlighted in spin-echo images by using short TR and TE to suppress the influence of T1l and to avoid (noncontrast contributing) T2 decay of the signal intensity.