论文部分内容阅读
Introduction:Cardiac T2* becomes a standard method to assess iron accumulation in myocardium.The reliability of T2* during the course of a longitudinal study could be affected by the variation of magnetic field inhomogeneity.We propose a novel technique for the cardiac T2* correction when the magnetic inhomogeneity is entangled.Objective:This study aims to find a correction method for cardiacT2* when the main magnetic field inhomogeneity was involved during the course of treatment.Materials and method:A stable reference(SR)T2*phantom filled with 20 different MnCl2concentrations(equivalent to the range of T2* from 1.31 ms.to 44.90 ms.)was scanned prior to 2 volunteers' scan.The second set of reference(SSR)phantom including 3 levels of T2* 9.06,13.63,20.31 ms,were placed to cover anterior body of the sternum and were scanned with short-axis view of the mid left ventricle of the 2 volunteers.Images were acquired with 10 echo times using the multi-echo gradient echo pulse sequences.Four sets of images were acquired including one control and 3 sets of images at 3 different locationsofmagnetic field perturbations.All scans were performed on a 1.5 T Achieva,Philips MRI scanner.The changes of the T2* of the SSR phantom due to the field perturbation were used to correct for the cardiac T2* by a piecewise quadratic interpolation fromthe SR phantom data.Results:Average cardiac T2* of the 2 volunteers as a control were 13.08 ms and 17.80 ms.Average cardiac T2* of the 3 different locations of field perturbation changed to 12.31 ms and 16.99 ms.When applied the novel correction techniques,the T2* of the 2 volunteers were 13.04 ms.and 17.77 ms.Conclusion:This new technique promisingly reduced the effect of magnetic inhomogeneity for the cardiac T2* measurements and provided more accurate T2*.