Decorrelation characteristics of transverse blood flow along an intravascular array catheter: Effects of aggregation of red blood cells

A method to measure transverse blood Bow, based on the correlation between consecutive radiofrequency (RF) signals, has been introduced. This method w as validated for an intravascular (IVUS) rotating single element catheter, Currently, we are implementing the method for an IVUS array transducer cath eter, The decorrelation characteristics during transverse blood flow using the IVUS array catheter mere investigated using computer modeling. Before t his, blood was simulated as a collection of randomly located point scattere rs and, by moving this scattering medium transversely across the acoustical beam, blood Bow was simulated, This paper presents a more realistic scatte ring media by simulating aggregates of red blood cells (RBCs) as strings of point scatterers. Three configurations of aggregates of RBCs were simulate d, First, aggregates of RBCs were strings with different lengths and parall el to the catheter axis. Second, the strings were with a fixed length and a ngles of plus or minus 45 degrees with respect to the catheter axis. Third, the strings were with different lengths and random angles ranging from -45 degrees to + 45 degrees. The decorrelation characteristics for these confi gurations of aggregates of RBCs were investigated and compared with point s catterers, For the aggregates of RBCs parallel to the catheter axis, the de correlation rate became slower when the aggregate length was increased. RBC aggregations with fixed and random lengths and angles resulted in a decorr elation rate that approaches the decorrelation pattern from point scatterer s. Results suggests that the presence of aggregates of RBCs will probably n ot affect the measurements of transverse blood flow using a decorrelation-b ased method and an IVUS array catheter, (C) 2001 World Federation for Ultra sound in Medicine & Biology.