Undersampled projection-reconstruction imaging for time-resolved contrast-enhanced imaging

In time-resolved contrast-enhanced 3D MR angiography, spatial resolution is traded for high temporal resolution. A hybrid method is presented that att empts to reduce this tradeoff in two of the spatial dimensions. It combines an undersampled projection acquisition in two dimensions with variable rat e k-space sampling in the third. Spatial resolution in the projection plane is determined by readout resolution and is limited primarily by signal-to- noise ratio. Oversampling the center of k-space combined with temporal k-sp ace interpolation provides time frames with minimal venous contamination, R esults demonstrating improved resolution in phantoms and volunteers are pre sented using angular undersampling factors up to eight with acceptable proj ection reconstruction artifacts. (C) 2000 Wiley-Liss, Inc.