Some useful concepts of matched filtering in intravenous digital subtraction angiography.

Using computer calculations and assumed contrast bolus curves, several aspects of the application of temporal integration methods and matched filtering to intravenous digital subtraction angiography (IV-DSA) were studied. The topics included the improvement in signal-to-noise ratio (SNR) of the final image provided by simple integration, a comparison of the SNR performance of matched filtering and extensive integration, the degradation of SNR caused by the motion of noniodinated objects and the sensitivity of SNR to variations in DSA bolus dynamics from patient to patient. Additionally the dependence of matched filter SNR on exposure position and duration was both estimated and demonstrated with clinical DSA images. The results indicate that a substantial improvement in SNR can be obtained with only moderate integration increasing to a two X improvement for longer durations. Integration methods are able to withstand moderate durations (2 seconds) of motion and still provide image quality superior to more conventional DSA results.