Mr digital subtraction angiography with asymmetric echo acquisition and complex subtraction: Improved lumen and stenosis visualization

The use of complex subtraction in dynamic thick slab 2D MR digital subtract ion angiography (MR-DSA) has been shown to eliminate partial volume effects , which are present if vessels cover a small fraction of the 2D slab. Howev er, spin dephasing still results in a poor visualization of areas with comp lex flow. In this paper, it is shown that this can be overcome by using asy mmetric echo (ASE) acquisition combined with complex subtraction. It is pro ven that an ASE acquisition does not destroy information necessary for comp lex subtraction if the subtraction is performed in k-space, As a consequenc e, the subtraction reconstruction is as reliable as the magnitude reconstru ction of a single ASE data set,Experiments with ASE and complex subtraction show that Bow voids near stenoses disappear, that the signal-to-noise rati o is improved and that temporal resolution is increased. (C) 1999 Elsevier Science Inc.