MR subtraction angiography with a matched filter.

The technique of matched filtering (MF) has been used in the past with X-ray digital subtraction angiography as a method of improving signal-to-noise ratio (SNR) in subtraction angiographic images. In this work we describe how MF can be applied to a series of images produced by cinematographic magnetic resonance (cine MR) to produce angiographic images. Likewise, a simple subtraction image can be formed by subtracting an image in which flow is not well visualized from an image at the same location but with flow visualization. Theory predicts that a subtraction image resulting from the MF technique will yield typical SNR improvements of 60% over results from simple subtraction. Twenty-one studies of the human popliteal, canine aorta, and canine carotid artery were undertaken in which MF was compared with simple subtraction. It was determined that cine MR can be used to produce subtraction angiographic images and that MF can produce a modest improvement in SNR over simple subtraction.