Cardiac echo-planar imaging suffers invariably from regions of severe distortion and T2(*) decay in the myocardium. The purpose of this work was to perform local measurements of T2(*) and field inhomogeneities in the myocardium and to identify the sources of focal signal loss and distortion. Field inhomogeneity maps and T2(*) were measured in five normal volunteers in short-axis slices spanning from base to apex. It was found that T2(*) ranged from 26 ms (SD = 7 ms, n = 5) to 41 ms (SD = 11 ms, n = 5) over most of the heart, and peak-to-peak field inhomogeneity differences were 71 Hz (SD = 14 Hz, n = 5). In all hearts, regions of severe signal loss were consistently adjacent to the posterior vein of the left ventricle; T2(*) in these regions was 12 ms (SD = 2 ms, n = 5), and the difference in resonance frequency with the surrounding myocardium was 70-100 Hz. These effects may be caused by increased magnetic susceptibility from deoxygenated blood in these veins.
- Cardiac imaging
- Echo planar imaging
- Field inhomogeneities
- Relaxation parameters
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging
- Radiological and Ultrasound Technology